You searched for subject:(Lignocellulose)
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Rhodes University
1.
Van Dyk, Jacoba Susanna.
Characterisation of the cellulolytic and hemicellulolytic system of Bacillus Licheniformis SVD1 and the isolation and characterisation of a multi-enzyme complex.
Degree: Faculty of Science, Biochemistry, Microbiology and Biotechnology, 2009, Rhodes University
URL: http://hdl.handle.net/10962/d1003995
► The biological degradation of lignocellulose into fermentable sugars for the production of liquid transportation fuels is feasible and sustainable, but equires a variety of enzymes…
(more)
▼ The biological degradation of lignocellulose into fermentable sugars for the production of liquid transportation fuels is feasible and sustainable, but equires a variety of enzymes working in synergy as lignocellulose is a complex and recalcitrant substrate. The cellulosome is a multi-enzyme complex (MEC) with a variety of cellulolytic and hemicellulolytic enzymes that appears to facilitate an enhanced synergy and efficiency, as compared to free enzymes, for the degradation of recalcitrant substrates such as lignocellulose and plant cell walls. Most of the studies on cellulosomes have focused on a few organisms; C. thermocellum, C. cellulovorans and C. cellulolyticum, and there is only limited knowledge vailable on similar complexes in other organisms. Some MECs have been identified in aerobic bacteria such as Bacillus circulans and Paenibacillus curdlanolyticus, but the nature of these MECs have not been fully elucidated. This study investigated the cellulolytic and emi-cellulolytic system of Bacillus licheniformis SVD1 with specific reference to the presence of a MEC, which has never been reported in the literature for B. licheniformis. A MEC of approximately 2,000 kDa in size, based on size exclusion chromatography using Sepharose 4B, was purified from a culture of B. licheniformis. When investigating the presence of enzyme activity in the total crude fraction as well as the MEC of a birchwood xylan culture, B. licheniformis was found to display a variety of enzyme activities on a range of substrates, although xylanases were by far the predominant enzyme activity present in both the crude and MEC fractions. Based on zymogram analysis there were three CMCases, seven xylanases, three mannanases and two pectinases in the crude fraction, while the MEC had two CMCases, seven xylanases, two mannanases and one pectinase. The pectinases in the crude could be identified as a pectin methyl esterase and a lyase, while the methyl esterase was absent in the MEC. Seventeen protein species could be detected in the MEC but only nine of these displayed activity on the substrates tested. The possible presence of a β-xylosidase in the crude fraction was deduced from thin layer chromatography (TLC) which demonstrated the production of xylose by the crude fraction. It was furthermore established that B. licheniformis SVD1 was able to regulate levels of enzyme expression based on the substrate the organism was cultured on. It was found that complexed xylanase activity had a pH optimum of between pH 6.0 and 7.0 and a temperature optimum of 55 °C. Complexed xylanase activity was found to be slightly inhibited by CaCl2 and inhibited to a greater extent by EDTA. Complexed xylanase activity was further shown to be activated in the presence of xylose and xylobiose, both compounds which are products of enzymatic degradation. Ethanol was found to inhibit complexed xylanase activity. The kinetic parameters for complexed xylanase activity were measured and the Km value was calculated as 2.84 mg/ml while the maximal velocity (Vmax) was calculated…
Subjects/Keywords: Lignocellulose; Lignocellulose – Biotechnology; Lignocellulose – Biodegradation; Plant biotechnology
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APA ·
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APA (6th Edition):
Van Dyk, J. S. (2009). Characterisation of the cellulolytic and hemicellulolytic system of Bacillus Licheniformis SVD1 and the isolation and characterisation of a multi-enzyme complex. (Thesis). Rhodes University. Retrieved from http://hdl.handle.net/10962/d1003995
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Van Dyk, Jacoba Susanna. “Characterisation of the cellulolytic and hemicellulolytic system of Bacillus Licheniformis SVD1 and the isolation and characterisation of a multi-enzyme complex.” 2009. Thesis, Rhodes University. Accessed April 13, 2021.
http://hdl.handle.net/10962/d1003995.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Van Dyk, Jacoba Susanna. “Characterisation of the cellulolytic and hemicellulolytic system of Bacillus Licheniformis SVD1 and the isolation and characterisation of a multi-enzyme complex.” 2009. Web. 13 Apr 2021.
Vancouver:
Van Dyk JS. Characterisation of the cellulolytic and hemicellulolytic system of Bacillus Licheniformis SVD1 and the isolation and characterisation of a multi-enzyme complex. [Internet] [Thesis]. Rhodes University; 2009. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/10962/d1003995.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Van Dyk JS. Characterisation of the cellulolytic and hemicellulolytic system of Bacillus Licheniformis SVD1 and the isolation and characterisation of a multi-enzyme complex. [Thesis]. Rhodes University; 2009. Available from: http://hdl.handle.net/10962/d1003995
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Oregon State University
2.
Fenske, John J.
Utilization of lignocellulosic polysaccharides.
Degree: PhD, Food Science and Technology, 1998, Oregon State University
URL: http://hdl.handle.net/1957/27269
► Lignocellulosic biomass represents a vast supply of fermentable carbohydrates and functional aromatic compounds. Conversion of lignocellulosics to ethanol and other useful products would be of…
(more)
▼ Lignocellulosic biomass represents a vast supply of fermentable carbohydrates
and functional aromatic compounds. Conversion of lignocellulosics to ethanol and other
useful products would be of widespread economical and environmental benefit. Better
understanding of the behavior of different lignicellulosic feedstocks in fermentation
protocols as well as catalytic activities involved in lignocellulosic depolymerization will
further enhance the commercial viability of biomass-to-ethanol conversion processes.
The relative toxicity of the combined non-xylose components in prehydrolysates
derived from three different lignocellulosic biomass feedstocks (poplar, corn stover and
switchgrass, or Panicum virgatum L.) was determined using a Pichia stipits fermentation
assay. The relative toxicity of the prehydrolysates, in decreasing order, was poplar-derived
prehydrolysates > switchgrass-derived prehydrolysates > corn stover-derived
prehydrolysates. Ethanol yields averaged 74%, 83% and 88% of control values for
poplar, switchgrass and corn stover prehydrolysates, respectively. Volumetric ethanol
productivities (g ethanol l⁻¹ h⁻¹) averaged 32%, 70% and 102% of control values for
poplar, switchgrass and corn stover prehydrolysates, respectively. Ethanol productivities
correlated closely with acetate concentrations in the prehydrolysates; however, regression lines correlating acetate concentrations and ethanol productivities were found to be
feedstock-dependent.
Differences in the relative toxicity of xylose-rich prehydrolysates derived from
woody and herbaceous feedstocks are likely due to the relative abundance of a variety of
inhibitory compounds, e.g. acetate and aromatic comounds. Fourteen aromatic monomers
present in prehydrolysates prepared from corn stover, switchgrass, and poplar were
tentatively identified by comparison with published mass spectra. The concentrations of
the aromatic monomers totaled 112, 141 and 247 mg(l)⁻¹ for corn stover, switchgrass and
poplar prehydrolysates, respectively. The woody and herbaceous feedstocks differed in
both amount and type of aromatic monomers.
The cellulases of Trichoderma reesei are the most widely studied for use in the
depolymerization of lignocellulosics. The Trichoderma cellobiohydrolases CBH1 and
CBH2 are traditionally categorized as exo-acting cellulases. A simple individual-based
model was created to explore the potential effects of native endo activity on substratevelocity
profiles. The model results indicate that an enzyme with a small amount of endo
activity will show an apparent substrate inhibition as substrate levels are increased.
Actual hydrolysis studies using affinity chromatography-purified CBH2 preparations
from three laboratories indicate that CBH2 has native endo activity, while CBH1 does
not.
Advisors/Committee Members: Penner, Michael H. (advisor), Bakalinsky, Alan Tagore (committee member).
Subjects/Keywords: Lignocellulose
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APA (6th Edition):
Fenske, J. J. (1998). Utilization of lignocellulosic polysaccharides. (Doctoral Dissertation). Oregon State University. Retrieved from http://hdl.handle.net/1957/27269
Chicago Manual of Style (16th Edition):
Fenske, John J. “Utilization of lignocellulosic polysaccharides.” 1998. Doctoral Dissertation, Oregon State University. Accessed April 13, 2021.
http://hdl.handle.net/1957/27269.
MLA Handbook (7th Edition):
Fenske, John J. “Utilization of lignocellulosic polysaccharides.” 1998. Web. 13 Apr 2021.
Vancouver:
Fenske JJ. Utilization of lignocellulosic polysaccharides. [Internet] [Doctoral dissertation]. Oregon State University; 1998. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1957/27269.
Council of Science Editors:
Fenske JJ. Utilization of lignocellulosic polysaccharides. [Doctoral Dissertation]. Oregon State University; 1998. Available from: http://hdl.handle.net/1957/27269

Oregon State University
3.
Meunier-Goddik, Lisbeth.
Conversion of lignocellulosic biomass : analysis of substrate characteristics.
Degree: PhD, Food Science and Technology, 1998, Oregon State University
URL: http://hdl.handle.net/1957/26187
► The objective of this research was to investigate the influence of physicochemical properties of lignocellulosic biomass on the rate and extent of cellulose conversion, i.e.…
(more)
▼ The objective of this research was to investigate the influence of physicochemical
properties of lignocellulosic biomass on the rate and extent of cellulose conversion, i.e.
the "hydrolyzability" of the substrate.
The initial two parts of this thesis investigated the interactions between various
components of pretreated biomass. The relevance of cellulase partitioning between the
cellulose and non-cellulose components of pretreated switchgrass was determined.
Furthermore, a method was developed to assess the changes in surface area of the non-cellulose
fraction during saccharification. The overall conclusion from these studies was
that for an optimally pretreated switchgrass sample the cellulose and non-cellulose
components are fully disassociated and the non-cellulose fraction does not appear to
interfere with cellulose conversion.
The third study determined the changes in physicochemical properties of native
and pretreated poplar during simultaneous saccharification and fermentation (SSF).
While this study gave an unprecedented insight into the dynamics of SSF, it was also
apparent that parameters measuring the complete feedstock are inadequate for explaining
cellulose reactivity/hydrolyzability during saccharification.
As a consequence of these conclusions, the final study focused on properties of
model celluloses and initial rates of hydrolysis by the major cellulase - CBHI. The
content of insoluble ends was measured by different modified soluble reducing sugar
assays and by tritium labeling through NaB³H₄ reduction reactions. The content of
insoluble reducing ends partially explained the relative initial rates of hydrolysis. However, comparisons between celluloses in their crystalline and corresponding
amorphous state revealed that crystallinity also accounts for some of the observed rate
differences. Furthermore, surface characteristics, such as the presence of pores, must be
considered to fully explain cellulose reactivity.
Advisors/Committee Members: Penner, Michael H. (advisor).
Subjects/Keywords: Lignocellulose
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Meunier-Goddik, L. (1998). Conversion of lignocellulosic biomass : analysis of substrate characteristics. (Doctoral Dissertation). Oregon State University. Retrieved from http://hdl.handle.net/1957/26187
Chicago Manual of Style (16th Edition):
Meunier-Goddik, Lisbeth. “Conversion of lignocellulosic biomass : analysis of substrate characteristics.” 1998. Doctoral Dissertation, Oregon State University. Accessed April 13, 2021.
http://hdl.handle.net/1957/26187.
MLA Handbook (7th Edition):
Meunier-Goddik, Lisbeth. “Conversion of lignocellulosic biomass : analysis of substrate characteristics.” 1998. Web. 13 Apr 2021.
Vancouver:
Meunier-Goddik L. Conversion of lignocellulosic biomass : analysis of substrate characteristics. [Internet] [Doctoral dissertation]. Oregon State University; 1998. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1957/26187.
Council of Science Editors:
Meunier-Goddik L. Conversion of lignocellulosic biomass : analysis of substrate characteristics. [Doctoral Dissertation]. Oregon State University; 1998. Available from: http://hdl.handle.net/1957/26187

Oregon State University
4.
Esteghlalian, Alireza.
Modeling and optimization of the dilute-sulfuric acid pretreatment of lignocellulosic.
Degree: PhD, Bioresource Engineering, 1996, Oregon State University
URL: http://hdl.handle.net/1957/34308
► Environmental concerns about urban air quality, global climate change, energy security and economic considerations motivate a growing interest in alternative fuels for the transportation sector.…
(more)
▼ Environmental concerns about urban air quality, global climate change, energy
security and economic considerations motivate a growing interest in alternative fuels for
the transportation sector. Ethanol, a fermentation-derived fuel, can be produced by
bioconversion of renewable materials, such as wood, grass, and waste. Combustion of
ethanol fuel, in both neat and blended form, can improve the engine efficiency, and lower
the emission of CO, NO[subscript x], and volatile organic compounds (VOC), hence reducing the
urban ozone level. Moreover, enhanced agricultural activities for production and
collection of lignocellulosic feedstocks and industrial developments for production of
ethanol will help the economic growth by creating new jobs and new income sources.
Bioconversion of lignocellulosic feedstocks into ethanol requires a pretreatment process to
increase the digestibility of cellulose by cellulolytic enzymes. The dilute-sulfuric acid
pretreatment can hydrolyze hemicelluloses (xylan), disrupt lignin structure, and increase
the yield of ethanol production from fermentation of monomeric units of cellulose
(glucose). In this study, herbaceous (corn stover and switchgrass) and woody (poplar
chips) feedstocks were pretreated with dilute sulfuric acid (0.6, 0.9, and 1.2% w/w) in a
batch reactor at relatively high temperatures (140, 160 and 180°C). A unifying kinetic
model including reaction time, temperature and acid concentration was developed, and
pertinent kinetic parameters were determined. This model can predict the percentages of
xylan remaining in the pretreated solids, net xylose yield in the liquid prehydrolysate, and
xylose loss after pretreatment of a feedstock at a certain set of reaction conditions. Using
this model, four optimum reaction conditions for obtaining maximum net xylose yield in
the liquid prehydrolysate were identified. The yield and rate of ethanol production from
the optimum prehydrolysates by the pentose fermenting yeast, Pichia stipitis, were
determined. It was found that pretreating the selected feedstocks at 170-180°C with 1.0-1.2% sulfuric acid for 1-3 min resulted in the recovery of 80-85% of the original xylan in
the liquid prehyrolysate. It was also found that feedstocks with higher neutralizing
capacity (e.g., corn stover) produced lower sugar yields as a result of acid neutralization.
Pretreatment of feedstocks at conditions beyond the optimum reaction conditions would
increase the extent of xylose degradation, and lower the yield and rate of ethanol
production due to loss of fermentable sugars and formation of toxic byproducts. The
optimum prehydrolysates of corn stover produced the highest yields of ethanol (0.39-0.47
g ethanol/g xylose) followed by switchgrass (0.36-0.45) and poplar (0.26-0.44). The
inhibitory effects of byproducts (e.g., acetate) was more pronounced in poplar
prehydrolysates.
Advisors/Committee Members: Hashimoto, Andrew G. (advisor), Bothwell, Michelle (committee member).
Subjects/Keywords: Lignocellulose
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Esteghlalian, A. (1996). Modeling and optimization of the dilute-sulfuric acid pretreatment of lignocellulosic. (Doctoral Dissertation). Oregon State University. Retrieved from http://hdl.handle.net/1957/34308
Chicago Manual of Style (16th Edition):
Esteghlalian, Alireza. “Modeling and optimization of the dilute-sulfuric acid pretreatment of lignocellulosic.” 1996. Doctoral Dissertation, Oregon State University. Accessed April 13, 2021.
http://hdl.handle.net/1957/34308.
MLA Handbook (7th Edition):
Esteghlalian, Alireza. “Modeling and optimization of the dilute-sulfuric acid pretreatment of lignocellulosic.” 1996. Web. 13 Apr 2021.
Vancouver:
Esteghlalian A. Modeling and optimization of the dilute-sulfuric acid pretreatment of lignocellulosic. [Internet] [Doctoral dissertation]. Oregon State University; 1996. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1957/34308.
Council of Science Editors:
Esteghlalian A. Modeling and optimization of the dilute-sulfuric acid pretreatment of lignocellulosic. [Doctoral Dissertation]. Oregon State University; 1996. Available from: http://hdl.handle.net/1957/34308

Michigan State University
6.
MacLellan, James.
Anaerobic treatment of lignocellulosic material for energy generation.
Degree: 2012, Michigan State University
URL: http://etd.lib.msu.edu/islandora/object/etd:918
► Thesis M.S. Michigan State University. Biosystems Engineering 2012.
Lignocellulosic material is a renewable and sustainable feedstock for the conversion to energy products. The anaerobic treatment…
(more)
▼ Thesis M.S. Michigan State University. Biosystems Engineering 2012.
Lignocellulosic material is a renewable and sustainable feedstock for the conversion to energy products. The anaerobic treatment breaks down the lignocellulosic material by a community of various microorganisms to produce energy. This treatment, often referred to as anaerobic digestion, has long been adopted by countries, such as Germany and Denmark, because of desirable waste management and energy recovery practices. A novel approach with anaerobic digestion is to use it as a pretreatment method to generate a feedstock that is beneficial for a biofuel production. In this report, raw corn stover was digested with swine manure taken from Michigan State University in 0.5 L reactors. Digestion performance and solid fiber quality were measured and assessed on five different ratios of corn stover to swine manure. Biogas and solid fiber were collected over a period of 60 days. The remaining fiber after digestion was further pretreated using optimized dilute alkali conditions (2% sodium hydroxide, 130°C, and 2 hours), enzymatically hydrolyzed on a 5% dry basis. Ethanol concentration was calculated based upon the glucose production from the fiber of each ratio. Mass and energy balances were evaluated to determine which ratio would be most beneficial for adoption into a biorefinery. The stover-to-manure ratio of 40:60 generated the most energy at 3.4 MJ kg-1dry raw feed, which was at most a 30% increase in total net energy compared to the other reactor ratios. The ratio effectively produced ethanol and methane at 41 and 101g kg-1dry raw feed, respectively. Using anaerobic digestion as an energy producer and as a feedstock generator for biorefinery processing can contribute to solving energy problems that are prevalent in this country.
Description based on online resource; title from PDF t.p. (ProQuest, viewed)
Advisors/Committee Members: Liao, Wei, Hodge, David, Liu, Yan.
Subjects/Keywords: Lignocellulose; Engineering
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
MacLellan, J. (2012). Anaerobic treatment of lignocellulosic material for energy generation. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:918
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
MacLellan, James. “Anaerobic treatment of lignocellulosic material for energy generation.” 2012. Thesis, Michigan State University. Accessed April 13, 2021.
http://etd.lib.msu.edu/islandora/object/etd:918.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
MacLellan, James. “Anaerobic treatment of lignocellulosic material for energy generation.” 2012. Web. 13 Apr 2021.
Vancouver:
MacLellan J. Anaerobic treatment of lignocellulosic material for energy generation. [Internet] [Thesis]. Michigan State University; 2012. [cited 2021 Apr 13].
Available from: http://etd.lib.msu.edu/islandora/object/etd:918.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
MacLellan J. Anaerobic treatment of lignocellulosic material for energy generation. [Thesis]. Michigan State University; 2012. Available from: http://etd.lib.msu.edu/islandora/object/etd:918
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Ryerson University
7.
Amin, Zeid.
Evaluation Of Mechanical, Irradiation And Chemical Pretreatment Lignocelulosic Substrate For Enhanced Methane Production.
Degree: 2017, Ryerson University
URL: https://digital.library.ryerson.ca/islandora/object/RULA%3A7117
► Lignocellulosic substrate is a resource that contains a locked energy reserve that is normally lost during anaerobic digestion. Lignocellulosic substrate is one of the most…
(more)
▼ Lignocellulosic substrate is a resource that contains a locked energy reserve that is normally lost during anaerobic digestion. Lignocellulosic substrate is one of the most abundant sources of organic matter available and yet its energy recovery has much room for improvement. Lignocellulosic substrate has cellular properties that are deemed extremely difficult to degrade due to complexity which is why this energy reserve is never unlocked during anaerobic digestion. There are several successful pretreatment methods that are used to degrade this lignocellulosic substrate and unlock this energy reserve. This paper will focus on the methods that include mechanical, irradiation, chemical and combined pretreatment processes. Analysis is conducted on all the studies that are obtained to compare the successes of the different types of pretreatment processes used. Each of the different listed pretreatment processes have different energy requirements, treatment times, and solvent requirement and are acting to enhancing methane production. The improvement in methane production varies from process to process and study to study creating a need to compile all of this valuable data into this research report. This will help future researchers in navigating the available studies of pretreatment of lignocellulosic substrate for improving methane production.
Subjects/Keywords: Lignocellulose – Biotechnology; Biodegradation; Methane; Lignocellulose – Biodegradation
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Amin, Z. (2017). Evaluation Of Mechanical, Irradiation And Chemical Pretreatment Lignocelulosic Substrate For Enhanced Methane Production. (Thesis). Ryerson University. Retrieved from https://digital.library.ryerson.ca/islandora/object/RULA%3A7117
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Amin, Zeid. “Evaluation Of Mechanical, Irradiation And Chemical Pretreatment Lignocelulosic Substrate For Enhanced Methane Production.” 2017. Thesis, Ryerson University. Accessed April 13, 2021.
https://digital.library.ryerson.ca/islandora/object/RULA%3A7117.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Amin, Zeid. “Evaluation Of Mechanical, Irradiation And Chemical Pretreatment Lignocelulosic Substrate For Enhanced Methane Production.” 2017. Web. 13 Apr 2021.
Vancouver:
Amin Z. Evaluation Of Mechanical, Irradiation And Chemical Pretreatment Lignocelulosic Substrate For Enhanced Methane Production. [Internet] [Thesis]. Ryerson University; 2017. [cited 2021 Apr 13].
Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A7117.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Amin Z. Evaluation Of Mechanical, Irradiation And Chemical Pretreatment Lignocelulosic Substrate For Enhanced Methane Production. [Thesis]. Ryerson University; 2017. Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A7117
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

McMaster University
8.
Li, Jinlei.
Chemical thermoplasticization of lignocellulosic fibers by reactive extrusion.
Degree: PhD, 2020, McMaster University
URL: http://hdl.handle.net/11375/25934
► Cellulosic thermoplastics are anticipated as promising replacements to petroleum-based thermoplastics, but their high manufacturing costs have limited wide-spread application. The primary objectives of this thesis…
(more)
▼ Cellulosic thermoplastics are anticipated as promising replacements to petroleum-based thermoplastics, but their high manufacturing costs have limited wide-spread application. The primary objectives of this thesis were to use low-cost
lignocellulose, practically forestry waste, as the raw material rather than more expensive purified cellulose in the preparation of new plastics and, consequently, to develop an economical reactive process focused on diminishing the use of expensive solvents in the thermoplasticization of
lignocellulose.
The thermoplasticization of lignocellulosic fibers started by developing a high solids content (60 wt%) twin-screw extrusion technique to defibrillate the raw material for the subsequent chemical modification. By this approach, the received lignocellulosic fibers showed improving handling as a feedstock for extrusion as well as chemical accessibility. To effectively wet the lignocellulosic fibers for chemical modification and avoid using expensive and largely ineffective solvents, a low-cost additive was derived by mimicking aspects of an ionic liquid using benzethonium chloride (hyamine) and sulfuric acid. The effectiveness of the hyamine/sulfuric acid wetting agent was demonstrated initially in a bench-top method where the additive also became chemically bonded to the
lignocellulose and strongly contributed to its thermoplasticity. During acetylation, this new and low-cost wetting/functionalizing agent converted the lignocellulosic fibers into a compression-moldable thermoplastic. The molar ratio of benzethonium chloride to sulfuric acid was found to be the most significant variable to determine grafting behaviour as well as degradation of the polymer chains.
Subsequently, this new modification chemistry was translated over to the environment of a twin-screw extruder to devise a continuous, greener method of thermoplasticization for
lignocellulose. The new reactive extrusion process had a short reaction time of 45-90 s and yet showed a good tendency for producing a flowable thermoplastic suitable for melt molding without plasticizers. A notable benefit to the method was the moldable lignocellulosic bioplastic maintained the excellent stiffness inherent to cellulose. Moreover, by the reactive extrusion method, the properties of the lignocellulosic thermoplastics were found to be tunable with the selected esterifying agents (butyric anhydride versus acetyl anhydride) and the molar ratio of benzethonium chloride to sulfuric acid. A statistical analysis based on a Design of Experiment method revealed details on desirable extrusion conditions.
The project concluded with improvements to the high solids-content process was exploring the novel concept of a recycle stream for reactive extrusion. The excessive esterifying agent content used in the initial studies was necessary to lubricate the fibrous mass inside the extruder else it would jam the process. This meant that the extrudate left the extruder with an unnecessary amount of reactant and required costly cleaning. The idea of…
Advisors/Committee Members: Thompson, Michael, Chemical Engineering.
Subjects/Keywords: Renewable; Thermoplastic; Lignocellulose
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Li, J. (2020). Chemical thermoplasticization of lignocellulosic fibers by reactive extrusion. (Doctoral Dissertation). McMaster University. Retrieved from http://hdl.handle.net/11375/25934
Chicago Manual of Style (16th Edition):
Li, Jinlei. “Chemical thermoplasticization of lignocellulosic fibers by reactive extrusion.” 2020. Doctoral Dissertation, McMaster University. Accessed April 13, 2021.
http://hdl.handle.net/11375/25934.
MLA Handbook (7th Edition):
Li, Jinlei. “Chemical thermoplasticization of lignocellulosic fibers by reactive extrusion.” 2020. Web. 13 Apr 2021.
Vancouver:
Li J. Chemical thermoplasticization of lignocellulosic fibers by reactive extrusion. [Internet] [Doctoral dissertation]. McMaster University; 2020. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/11375/25934.
Council of Science Editors:
Li J. Chemical thermoplasticization of lignocellulosic fibers by reactive extrusion. [Doctoral Dissertation]. McMaster University; 2020. Available from: http://hdl.handle.net/11375/25934

RMIT University
9.
McKenzie, B.
Heterologous expression of cellulase enzymes in transplastidic Nicotiana tabacum cv. Petit Havana.
Degree: 2008, RMIT University
URL: http://researchbank.rmit.edu.au/view/rmit:6741
► Extensive research into enzyme-induced bio-conversion of lignocellulose to soluble sugars has been conducted and research continues in this area. Several approaches have been taken to…
(more)
▼ Extensive research into enzyme-induced bio-conversion of lignocellulose to soluble sugars has been conducted and research continues in this area. Several approaches have been taken to attempt to alleviate the economic problems associated with utilisation of lignocellulose in fuel ethanol production. By expressing cellulase genes in planta, it is hoped that the cost of enzyme-mediated hydrolysis of cellulose to its soluble sugar monomers, will be reduced. Some accomplishments have been made in this area using nuclear genetic transformation (Abdeev et al., 2003; Abdeev et al., 2004; Austin-Phillips et al., 1999; Biswas et al., 2006; Dai et al., 2000a,b; Dai et al., 2005; Jin et al., 2003; Kawazu et al., 1999; Sakka et al., 2000; Ziegelhoffer et al., 1999; Ziegelhoffer et al., 2001; Ziegler et al., 2000), but more research is required to bring the levels of cellulase enzyme expression in plants to levels that will make the process economically competitive. Chloroplasts of N. tabacum were selected as a target for transformation for high level expression due to their extremely high rates of transcription and translation. These were transformed with two genes, the e1 gene from A. cellulolyticus, and the cbh1 gene from T. reesei. Further aims included the investigation of the effects of using different promoters, and the novel use of both nuclear and chloroplast-based expression in a single plant, on the level of protein production in the heterologous host. Heterologous expression of the cbh1 gene was not successful. This is thought to be due to toxicity of the protein in a prokaryotic environment. Future studies should focus on trying to avoid this toxicity by targeting of the chloroplast-expressed enzyme to specific tissues, such as the thylakoid membrane, for containment, creating a codon-optimised synthetic gene that better mimics the codon usage of the plant to be used for expression, or placing the expression under a reactive cascade that is only activated upon exposure to an external trigger. Heterologous expression of the full length gene for E1 from A. cellulolyticus was successful. Chloroplast homology vectors under the constitutive promoter Prrn, and the inducible promoter T7, were constructed and these were used to successfully transform N. tabacum cv. Petit Havana chloroplasts. Stable transgenic plants were produced and evaluated by a variety of means, with the heterologously expressed enzyme showing activity against the soluble substrate analogue MUC of up to 3122 ± 466 pmol 4-MU/mg TSP/min and an E1 accumulation level of up to 0.35% ± 0.06 of the total soluble protein. Lastly, chloroplast transformation was combined with nuclear transformation to create novel dual-transgenic plants simultaneously expressing E1 from both the nuclear and chloroplast genomes. The combination of these technologies was very successful, with the heterologously expressed enzyme showing activity against the soluble substrate analogue MUC of up to 35706 ± 955 pmol 4-MU/mg TSP/min and an E1 accumulation level of up to 4.78%…
Subjects/Keywords: Fields of Research; Lignocellulose Biotechnology
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APA (6th Edition):
McKenzie, B. (2008). Heterologous expression of cellulase enzymes in transplastidic Nicotiana tabacum cv. Petit Havana. (Thesis). RMIT University. Retrieved from http://researchbank.rmit.edu.au/view/rmit:6741
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
McKenzie, B. “Heterologous expression of cellulase enzymes in transplastidic Nicotiana tabacum cv. Petit Havana.” 2008. Thesis, RMIT University. Accessed April 13, 2021.
http://researchbank.rmit.edu.au/view/rmit:6741.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
McKenzie, B. “Heterologous expression of cellulase enzymes in transplastidic Nicotiana tabacum cv. Petit Havana.” 2008. Web. 13 Apr 2021.
Vancouver:
McKenzie B. Heterologous expression of cellulase enzymes in transplastidic Nicotiana tabacum cv. Petit Havana. [Internet] [Thesis]. RMIT University; 2008. [cited 2021 Apr 13].
Available from: http://researchbank.rmit.edu.au/view/rmit:6741.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
McKenzie B. Heterologous expression of cellulase enzymes in transplastidic Nicotiana tabacum cv. Petit Havana. [Thesis]. RMIT University; 2008. Available from: http://researchbank.rmit.edu.au/view/rmit:6741
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Nelson Mandela Metropolitan University
10.
Molaba, Tshepiso Princess.
Long term effects of temperature and humidity on lignocellulosic fibres and composites.
Degree: Faculty of Science, 2015, Nelson Mandela Metropolitan University
URL: http://hdl.handle.net/10948/10276
► The study deals with the chemical and flame retardant (FR) treatment of woven flax fabric and preparation and characterization of flax reinforced phenolic composites. Sheets…
(more)
▼ The study deals with the chemical and flame retardant (FR) treatment of woven flax fabric and preparation and characterization of flax reinforced phenolic composites. Sheets of flax fabric were subjected to chemical treatments using NaOH and silane coupling agents. A phosphate-based flame retardant (DAP) was applied to decrease the flammability of the flax fabric. The effect of the chemical treatments and FR treatments on the thermal and flammability properties of the fabric and composites was investigated using thermogravimetric analysis (TGA), vertical flame resistance test and cone calorimeter. The mechanical properties of the flax fabric and composites, before and after environmental ageing, were investigated. Ageing studies were carried out by exposing the samples in an environmental chamber at specified conditions for two weeks. TGA results showed that the treatment of the fabric with FR shifts the decomposition temperature to lower level and increases the char residue. Vertical flame resistance testing showed that FR treatment of the flax fabric improved the flammability properties. There was no after flame and afterglow observed for FR treated flax fabric due to self-extinguishment after removal of the flame. Flax Fabric without FR burned completely and there was no result for the char length due to the complete destruction of the fabric. The FR treatment, however, seemed to have had a negative effect on the tensile strength of the flax fabric. This was further intensified upon exposure of FR treated flax fabric to high temperatures during ageing studies which drastically reduced the tensile strength by more than 90%, and the flax fabric were found to be brittle and darker in visual appearance. TGA results of flax/phenolic composites showed that for composites containing chemically treated and FR treated flax fabric the decomposition temperatures shifted to lower temperatures; however there was no significant difference in the amount of char residue. Untreated flax/phenolic composites exhibited the lowest char residue. Cone calorimeter results showed that the peak heat release rate (PHRR), smoke production rate (SPR) and carbon dioxide (CO2) emission rate was reduced for the flax/phenolic composite produced using FR treated flax fabric. The tensile strength of these composites was reduced while there was an increase in modulus value. Exposure of the FR treated composites to high temperatures further reduced the tensile strength and increased the E-modulus. Both FR treated and untreated composites changed in colour and the FR treated composites were found to be brittle after exposure to high temperatures.
Subjects/Keywords: Lignocellulose; Fibrous composites; Textile fabrics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Molaba, T. P. (2015). Long term effects of temperature and humidity on lignocellulosic fibres and composites. (Thesis). Nelson Mandela Metropolitan University. Retrieved from http://hdl.handle.net/10948/10276
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Molaba, Tshepiso Princess. “Long term effects of temperature and humidity on lignocellulosic fibres and composites.” 2015. Thesis, Nelson Mandela Metropolitan University. Accessed April 13, 2021.
http://hdl.handle.net/10948/10276.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Molaba, Tshepiso Princess. “Long term effects of temperature and humidity on lignocellulosic fibres and composites.” 2015. Web. 13 Apr 2021.
Vancouver:
Molaba TP. Long term effects of temperature and humidity on lignocellulosic fibres and composites. [Internet] [Thesis]. Nelson Mandela Metropolitan University; 2015. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/10948/10276.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Molaba TP. Long term effects of temperature and humidity on lignocellulosic fibres and composites. [Thesis]. Nelson Mandela Metropolitan University; 2015. Available from: http://hdl.handle.net/10948/10276
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Ryerson University
11.
Kang, Jin.
Improving bio-butanol production from lignocellulosic feedstock by tailoring metabolic perturbations.
Degree: 2017, Ryerson University
URL: https://digital.library.ryerson.ca/islandora/object/RULA%3A7282
► The objective of this study is to enhance bio-butanol production using lignocellulosic feedstock via supplements of metabolism perturbation. Metabolic perturbations are non-substrate-based chemical additives that…
(more)
▼ The objective of this study is to enhance bio-butanol production using lignocellulosic feedstock via supplements of metabolism perturbation. Metabolic perturbations are non-substrate-based chemical additives that can reinforce metabolic flux towards butanol formation, or increase tolerance to microbial inhibitors in the feedstock. Typical metabolic perturbations include CaCO3, ZnSO4, methyl red, and furan derivatives such as furfural and hydroxymethylfurfural (HMF). In this study, we stepwise tailored metabolic perturbations to maximize butanol production from pure sugar and lignocellulosic feedstock. Under optimized conditions of 4 g/L CaCO3, 2 mg/L ZnSO4, butanol production exceeded 10g/L in wheat straw hydrolysate, which was significantly higher than that obtained in the absent of ZnSO4 and CaCO3. As compared to traditional lignocellulosic feedstock post-treatment method, metabolic perturbations method shows advantages in terms of productivity and economics. Improved bio-butanol production is related to the overexpression of NAD(P)H dependent genes.
Subjects/Keywords: Lignocellulose – Biotechnology; Butanol; Biomass energy
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kang, J. (2017). Improving bio-butanol production from lignocellulosic feedstock by tailoring metabolic perturbations. (Thesis). Ryerson University. Retrieved from https://digital.library.ryerson.ca/islandora/object/RULA%3A7282
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Kang, Jin. “Improving bio-butanol production from lignocellulosic feedstock by tailoring metabolic perturbations.” 2017. Thesis, Ryerson University. Accessed April 13, 2021.
https://digital.library.ryerson.ca/islandora/object/RULA%3A7282.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Kang, Jin. “Improving bio-butanol production from lignocellulosic feedstock by tailoring metabolic perturbations.” 2017. Web. 13 Apr 2021.
Vancouver:
Kang J. Improving bio-butanol production from lignocellulosic feedstock by tailoring metabolic perturbations. [Internet] [Thesis]. Ryerson University; 2017. [cited 2021 Apr 13].
Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A7282.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Kang J. Improving bio-butanol production from lignocellulosic feedstock by tailoring metabolic perturbations. [Thesis]. Ryerson University; 2017. Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A7282
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Oregon State University
12.
Tantasucharit, Usicha.
Porosity, surface area and enzymatic saccharification of microcrystalline cellulose.
Degree: MS, Food Science and Technology, 1995, Oregon State University
URL: http://hdl.handle.net/1957/25991
► The research described in this thesis was aimed at understanding how particle size, porosity, and enzyme accessible surface area influence the rate of saccharification of…
(more)
▼ The research described in this thesis was aimed at understanding how particle
size, porosity, and enzyme accessible surface area influence the rate of saccharification
of microcrystalline cellulose. Microcrystalline cellulose (MCC) is a commonly used
substrate for the study of cellulolytic enzymes. MCC preparations of different particle
size are commercially available. In this study, MCC preparations having average particle
sizes of 20, 50, and 90 μm were analyzed with respect to their enzyme accessible surface
area, chemical and physical properties and rates of enzymatic saccharification.
Saccharification studies were done using a commercially available cellulase preparation
from Trichoderma reesei. Pore volume distributions were determined from solute
exclusion experiments. Internal surface areas were calculated based on the application of
the lamellae model to the pore volume distribution data. External surface areas were
calculated based on the average particle size of each MCC preparation assuming that the
particles could be represented as solid spheres. The different MCC preparations were
found to have nearly equivalent enzyme accessible surface areas per unit weight. Greater
than 99 % of the total enzyme accessible surface area for each MCC preparations was
found to be within the porous structure of the particles. Enzymatic saccharification
experiments demonstrated that the smaller particle size MCCs were more readily
digested than those of larger particle size. The similarity of the three MCC preparations
with respect to chemical and physical properties (other than particle size), pore volume
distribution, and total enzyme accessible surface area suggests that a rate limiting factor
in the enzymatic digestion of MCC is a resistance attributable to diffusion within the
capillary network of these insoluble substrates.
Advisors/Committee Members: Penner, Michael H. (advisor), Gamble, W. (committee member).
Subjects/Keywords: Lignocellulose – Biodegradation
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
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APA (6th Edition):
Tantasucharit, U. (1995). Porosity, surface area and enzymatic saccharification of microcrystalline cellulose. (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/25991
Chicago Manual of Style (16th Edition):
Tantasucharit, Usicha. “Porosity, surface area and enzymatic saccharification of microcrystalline cellulose.” 1995. Masters Thesis, Oregon State University. Accessed April 13, 2021.
http://hdl.handle.net/1957/25991.
MLA Handbook (7th Edition):
Tantasucharit, Usicha. “Porosity, surface area and enzymatic saccharification of microcrystalline cellulose.” 1995. Web. 13 Apr 2021.
Vancouver:
Tantasucharit U. Porosity, surface area and enzymatic saccharification of microcrystalline cellulose. [Internet] [Masters thesis]. Oregon State University; 1995. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1957/25991.
Council of Science Editors:
Tantasucharit U. Porosity, surface area and enzymatic saccharification of microcrystalline cellulose. [Masters Thesis]. Oregon State University; 1995. Available from: http://hdl.handle.net/1957/25991

Oregon State University
13.
Fenske, John J.
Quantitative polysaccharide analysis of lignocellulosic biomass.
Degree: MS, Food Science and Technology, 1994, Oregon State University
URL: http://hdl.handle.net/1957/27278
► Lignocellulosic biomass is a potential source of fermentable sugars such as glucose. Enzymatic hydrolysis of cellulose is a viable method of solubilizing the glucose from…
(more)
▼ Lignocellulosic biomass is a potential source of fermentable sugars such as
glucose. Enzymatic hydrolysis of cellulose is a viable method of solubilizing the
glucose from biomass, but the cellulose fraction of native lignocellulosic material
is shielded from enzymatic attack by the lignin-hemicellulose matrix
surrounding it. Pretreating lignocellulosic biomass with dilute sulfuric acid at
high temperatures solubilizes hemicellulose, rendering the cellulose fraction
more susceptible to enzymatic hydrolysis. Evaluation of dilute-acid, high-temperature
pretreatments depends on polysaccharide analysis of the two
fractions resulting from a pretreatment, prehydrolyzed solids(PHS) and
prehydrolyzate liquid(PH). The polysaccharide analysis is based on a method
described by the National Renewable Energy Laboratory and involves a two-stage
sulfuric acid hydrolysis followed by HPLC quantification using ion-moderated
partition chromatography and refractive index detection. The
subject
of this thesis is identifying and quantifying the sources of error associated with
the polysaccharide analysis and the error associated with the evaluation of the
effects of pretreatment on the polysaccharide fractions of switchgrass and poplar.
This was addressed by conducting replicate polysaccharide analyses on single
samples of native biomass, PHS, and PH. The variability associated with these
measurements was compared to the variability associated with replicate analyses
of identically pretreated biomass. It was found that the use of sugar standards to correct for sugar destroyed during the analysis adds error and most likely
overestimates the amount of sugar from biomass actually destroyed. It is evident
that assuming a volume after neutralization of the hydrolyzed biomass sample is
more reproducible than measuring the volume. When using a batch-type reactor
and the temperature and acid parameters used in this study,140°C-180°C/ 0.6-1.2
% sulfuric acid (w/w), it is evident that the major source of error in evaluating
pretreatment conditions is the pretreatment itself, not the analysis.
Advisors/Committee Members: Penner, Michael H. (advisor).
Subjects/Keywords: Lignocellulose – Biodegradation
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MLA ·
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APA (6th Edition):
Fenske, J. J. (1994). Quantitative polysaccharide analysis of lignocellulosic biomass. (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/27278
Chicago Manual of Style (16th Edition):
Fenske, John J. “Quantitative polysaccharide analysis of lignocellulosic biomass.” 1994. Masters Thesis, Oregon State University. Accessed April 13, 2021.
http://hdl.handle.net/1957/27278.
MLA Handbook (7th Edition):
Fenske, John J. “Quantitative polysaccharide analysis of lignocellulosic biomass.” 1994. Web. 13 Apr 2021.
Vancouver:
Fenske JJ. Quantitative polysaccharide analysis of lignocellulosic biomass. [Internet] [Masters thesis]. Oregon State University; 1994. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1957/27278.
Council of Science Editors:
Fenske JJ. Quantitative polysaccharide analysis of lignocellulosic biomass. [Masters Thesis]. Oregon State University; 1994. Available from: http://hdl.handle.net/1957/27278

Oregon State University
14.
Chung, Yun-Chin.
Saccharification and fermentation of lignocellulosic biomass using Trichoderma reesei cellulases and Saccharomyces cerevisiae.
Degree: PhD, Food Science and Technology, 1996, Oregon State University
URL: http://hdl.handle.net/1957/27186
► The efficiency of cellulose hydrolysis under straight saccharification and simultaneous saccharification and fermentation (SSF) conditions was evaluated using three lignocellulosic materials (switchgrass, cornstover, and poplar),…
(more)
▼ The efficiency of cellulose hydrolysis under straight saccharification and
simultaneous saccharification and fermentation (SSF) conditions was evaluated using three
lignocellulosic materials (switchgrass, cornstover, and poplar), which had been pretreated
with dilute sulfuric acid under conditions which optimized xylose concentrations in the
prehydrolysate liquid. Yields of glucose, cellobiose and ethanol obtained from the
pretreated feedstocks were measured over 168 hrs. The final theoretical conversions of
cellulose from pretreated switchgrass, cornstover, and poplar in straight saccharification
were 85-100% (average 94%), 84-100% (average 96%), and 75-100% (average 87%),
respectively, while in SSF the conversions were 84-90% (average 87%), 91-96% (average
90%), 72%-82% (average 76%), respectively. The conversion rates of poplar in straight
saccharification and SSF were significantly lower than those of switchgrass and
cornstover. The effects of reaction parameters such as enzyme activity, cellulose
availability, and yeast cell viability on the extent of hydrolysis in straight saccharification and SSF were also studied. Results indicate that the lower glucose or ethanol yields
associated with some of the poplar were due to the recalcitrant nature of its cellulose.
To compare accurately the efficiencies between straight saccharification and SSF,
a direct method for determining the cellulose content of the feedstocks residues resulting
from SSF experiments has been developed and evaluated. The method improves on
classical cellulose assays by incorporating a yeast lysing enzyme to remove yeast glucans
from the feedstocks residue prior to acid hydrolysis and subsequent quantification of
cellulose derived glucose. A freeze-drying step was identified as necessary to render the
SSF yeast cells susceptible to enzyme lysis. The method was applied to the analysis of the
cellulose and yeast-glucan content of SSF residues from the three pretreated feedstocks.
Cellulose assays employing the lysing enzyme preparation demonstrated relative errors up
to 7.2% when yeast-associated glucan were not removed prior to analysis of SSF residues.
Enzymatic lysis of SSF yeast cells may be viewed as a general preparatory procedure to be
used prior to the subsequent chemical and physical analysis of SSF residues.
Advisors/Committee Members: Penner, Michael H. (advisor), Hashimoto, Andrew (committee member).
Subjects/Keywords: Lignocellulose – Biodegradation
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Chung, Y. (1996). Saccharification and fermentation of lignocellulosic biomass using Trichoderma reesei cellulases and Saccharomyces cerevisiae. (Doctoral Dissertation). Oregon State University. Retrieved from http://hdl.handle.net/1957/27186
Chicago Manual of Style (16th Edition):
Chung, Yun-Chin. “Saccharification and fermentation of lignocellulosic biomass using Trichoderma reesei cellulases and Saccharomyces cerevisiae.” 1996. Doctoral Dissertation, Oregon State University. Accessed April 13, 2021.
http://hdl.handle.net/1957/27186.
MLA Handbook (7th Edition):
Chung, Yun-Chin. “Saccharification and fermentation of lignocellulosic biomass using Trichoderma reesei cellulases and Saccharomyces cerevisiae.” 1996. Web. 13 Apr 2021.
Vancouver:
Chung Y. Saccharification and fermentation of lignocellulosic biomass using Trichoderma reesei cellulases and Saccharomyces cerevisiae. [Internet] [Doctoral dissertation]. Oregon State University; 1996. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1957/27186.
Council of Science Editors:
Chung Y. Saccharification and fermentation of lignocellulosic biomass using Trichoderma reesei cellulases and Saccharomyces cerevisiae. [Doctoral Dissertation]. Oregon State University; 1996. Available from: http://hdl.handle.net/1957/27186

University of Waikato
15.
Williams, Thomas Carl.
The Microflora of the Huhu Grub
.
Degree: 2011, University of Waikato
URL: http://hdl.handle.net/10289/5336
► New Zealand's endemic longhorned beetle larvae, the Huhu grub (Prionoplus reticularis) feeds on dead coniferous wood. No studies have been conducted on its gut microflora.…
(more)
▼ New Zealand's endemic longhorned beetle larvae, the Huhu grub (Prionoplus reticularis) feeds on dead coniferous wood. No studies have been conducted on its gut microflora. Given that the Huhu grub feeds solely on lignocelluloses, it is likely that there are microorganisms present in its gut which are capable of degrading lignocelluloses to release energy rich sugars. This process of lignocelluloses release is the rate limiting step in the utilisation of woody material for bioprocesses such as bioethanol production. Microbial communities from wild grubs were compared with those raised on laboratory diets of either:
lignocellulose, cellulose, or complex nutrients. Bacterial gut communities were surveyed using 454 pyrosequencing of the variable 5 and 6 regions (400nt reads) of bacterial 16S rRNA genes as well as clone library analysis of the full length gene (1500bp). Fungal gut communities were analysed using cloning and Sanger sequencing of amplified fungal intergenic spacer (ITS) regions. The wild type gut bacterial population was highly diverse, with no known cellulose or lignin degraders detected in any abundance, although a strain of Burkholderia thought to be capable of nitrogen fixation was detected. No methanogenic archaea or acetogenic bacteria were detected. Fungal ITS sequences had high similarity with those of known lignin, hemicellulose and cellulose degraders in the public databases, and an uncultured Basidiomycete made up 51% of the wild type community, while species of the Penicillium genus dominated the grubs reared on laboratory diets of
lignocellulose. When grubs were reared on a diet of only cellulose the fungal community was dominated by a single species identified as Candida shehatae, a hemicellulose degrader known to associate with other longhorned beetle larvae. These fungi may be of interest for the biological conversion of lignocelluloses.
Advisors/Committee Members: Morgan, Hugh W (advisor).
Subjects/Keywords: Huhu;
Basidiomycete;
Burkholderia;
Penicillium;
Lignocellulose
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Williams, T. C. (2011). The Microflora of the Huhu Grub
. (Masters Thesis). University of Waikato. Retrieved from http://hdl.handle.net/10289/5336
Chicago Manual of Style (16th Edition):
Williams, Thomas Carl. “The Microflora of the Huhu Grub
.” 2011. Masters Thesis, University of Waikato. Accessed April 13, 2021.
http://hdl.handle.net/10289/5336.
MLA Handbook (7th Edition):
Williams, Thomas Carl. “The Microflora of the Huhu Grub
.” 2011. Web. 13 Apr 2021.
Vancouver:
Williams TC. The Microflora of the Huhu Grub
. [Internet] [Masters thesis]. University of Waikato; 2011. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/10289/5336.
Council of Science Editors:
Williams TC. The Microflora of the Huhu Grub
. [Masters Thesis]. University of Waikato; 2011. Available from: http://hdl.handle.net/10289/5336

Michigan State University
16.
Bradshaw, Tamika Calicia.
Enzymatic hydrolysis of ammonia fiber explosion (AFEX) pretreated reed canarygrass and switchgrass.
Degree: MS, Department of Chemical Engineering and Materials Science, 2005, Michigan State University
URL: http://etd.lib.msu.edu/islandora/object/etd:33860
Subjects/Keywords: Hydrolysis; Lignocellulose
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Bradshaw, T. C. (2005). Enzymatic hydrolysis of ammonia fiber explosion (AFEX) pretreated reed canarygrass and switchgrass. (Masters Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:33860
Chicago Manual of Style (16th Edition):
Bradshaw, Tamika Calicia. “Enzymatic hydrolysis of ammonia fiber explosion (AFEX) pretreated reed canarygrass and switchgrass.” 2005. Masters Thesis, Michigan State University. Accessed April 13, 2021.
http://etd.lib.msu.edu/islandora/object/etd:33860.
MLA Handbook (7th Edition):
Bradshaw, Tamika Calicia. “Enzymatic hydrolysis of ammonia fiber explosion (AFEX) pretreated reed canarygrass and switchgrass.” 2005. Web. 13 Apr 2021.
Vancouver:
Bradshaw TC. Enzymatic hydrolysis of ammonia fiber explosion (AFEX) pretreated reed canarygrass and switchgrass. [Internet] [Masters thesis]. Michigan State University; 2005. [cited 2021 Apr 13].
Available from: http://etd.lib.msu.edu/islandora/object/etd:33860.
Council of Science Editors:
Bradshaw TC. Enzymatic hydrolysis of ammonia fiber explosion (AFEX) pretreated reed canarygrass and switchgrass. [Masters Thesis]. Michigan State University; 2005. Available from: http://etd.lib.msu.edu/islandora/object/etd:33860
17.
Schulz, Roland.
Development of High Performance Molecular Dynamics with Application to Multimillion-Atom Biomass Simulations.
Degree: 2015, University of Tennessee – Knoxville
URL: https://trace.tennessee.edu/utk_graddiss/3468
► An understanding of the recalcitrance of plant biomass is important for efficient economic production of biofuel. Lignins are hydrophobic, branched polymers and form a residual…
(more)
▼ An understanding of the recalcitrance of plant biomass is important for efficient economic production of biofuel. Lignins are hydrophobic, branched polymers and form a residual barrier to effective hydrolysis of lignocellulosic biomass. Understanding lignin's structure, dynamics and its interaction and binding to cellulose will help with finding more efficient ways to reduce its contribution to the recalcitrance. Molecular dynamics (MD) using the GROMACS software is employed to study these properties in atomic detail. Studying complex, realistic models of pretreated plant cell walls, requires simulations significantly larger than was possible before. The most challenging part of such large simulations is the computation of the electrostatic interaction. As a solution, the reaction-field (RF) method has been shown to give accurate results for lignocellulose systems, as well as good computational efficiency on leadership class supercomputers. The particle-mesh Ewald method has been improved by implementing 2D decomposition and thread level parallelization for molecules not accurately modeled by RF. Other scaling limiting computational components, such as the load balancing and memory requirements, were identified and addressed to allow such large scale simulations for the first time. This work was done with the help of modern software engineering principles, including code-review, continuous integration, and integrated development environments. These methods were adapted to the special requirements for scientific codes. Multiple simulations of lignocellulose were performed. The simulation presented primarily, explains the temperature-dependent structure and dynamics of individual softwood lignin polymers in aqueous solution. With decreasing temperature, the lignins are found to transition from mobile, extended to glassy, compact states. The low-temperature collapse is thermodynamically driven by the increase of the translational entropy and density fluctuations of water molecules removed from the hydration shell.
Subjects/Keywords: Lignocellulose; Molecular Dynamics; Supercomputer; Biophysics
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APA (6th Edition):
Schulz, R. (2015). Development of High Performance Molecular Dynamics with Application to Multimillion-Atom Biomass Simulations. (Doctoral Dissertation). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_graddiss/3468
Chicago Manual of Style (16th Edition):
Schulz, Roland. “Development of High Performance Molecular Dynamics with Application to Multimillion-Atom Biomass Simulations.” 2015. Doctoral Dissertation, University of Tennessee – Knoxville. Accessed April 13, 2021.
https://trace.tennessee.edu/utk_graddiss/3468.
MLA Handbook (7th Edition):
Schulz, Roland. “Development of High Performance Molecular Dynamics with Application to Multimillion-Atom Biomass Simulations.” 2015. Web. 13 Apr 2021.
Vancouver:
Schulz R. Development of High Performance Molecular Dynamics with Application to Multimillion-Atom Biomass Simulations. [Internet] [Doctoral dissertation]. University of Tennessee – Knoxville; 2015. [cited 2021 Apr 13].
Available from: https://trace.tennessee.edu/utk_graddiss/3468.
Council of Science Editors:
Schulz R. Development of High Performance Molecular Dynamics with Application to Multimillion-Atom Biomass Simulations. [Doctoral Dissertation]. University of Tennessee – Knoxville; 2015. Available from: https://trace.tennessee.edu/utk_graddiss/3468

University of Edinburgh
18.
Munns, Craig Christopher Robert.
Development of physio-chemical pretreatments and mixed microbial cultures for the conversion of lignocellulosic biomass to useful products.
Degree: PhD, 2017, University of Edinburgh
URL: http://hdl.handle.net/1842/28768
► There is increasing interest in producing biofuels; biofuels are preferable to fossil fuels as the biomass from which they are derived is seen as a…
(more)
▼ There is increasing interest in producing biofuels; biofuels are preferable to fossil fuels as the biomass from which they are derived is seen as a renewable source, as opposed to fossil fuels which are a finite resource. “First Generation” biofuels are derived from food crops such as grains and sugar cane. The use of food crops is not sustainable in this age of increasing food insecurity. A promising alternative appears to be what is termed “Second Generation” feedstocks, such as energy crops like Miscanthus spp., and agricultural by-products. The problem with the use of second generation feedstocks is firstly that the sugars are locked up in the cell wall polymers (CWP), which need to be released by physio-chemical pre-treatments, that are costly and time consuming. The second problem is that not all the sugars that are released from CWP are able to be utilised by wild type product-forming organisms. However, model chassis organisms can be genetically modified to utilise these sugars and /or produce enzymes to degrade biomass which reduces the time and costs involved in the process. While engineering these organisms to utilise a range of monosaccharides has already been successful, engineering them to produce degradation enzymes is proving to be problematic. A potentially more effective system is to use co-cultures of both cellulose-degrading and product-forming organisms. Since this is a novel approach it is not known whether the two organisms are able to live together without any adverse effects. The aims of this study were firstly to determine whether mixed cultures of both cellulose-degrading and potential product-forming organisms could survive in the presence of one another, secondly whether the cellulose-degrading organisms could degrade potential feedstock down into their monosaccharide building blocks and thirdly whether the potential product-forming organisms could survive and utilise these monosaccharides for growth and potential fermentation. It was discovered that C. hutchinsonii can degrade both paper and Triticum aestivum straw polymers into their monosaccharide components and that B. subtilis can survive on the sugars released by C. hutchinsonii. It was also discovered that C. hutchinsonii and B. subtilis 168 can only tolerate an ethanol concentration of up to 2% (v/v) and that this is below the baseline for a biofuel system to be economically viable. Likewise, C. hutchinsonii and B. subtilis 168 have an even poorer tolerance for butanol; growth is inhibited by < 1% butanol in its growth media. A series of physio-chemical pre-treatments were developed in order to make the monosaccharides present in the cell wall polymers more accessible to microbial saccharification. Sequential pre-treatments, both physical milling and chemical hydrolysis in tandem, had the greatest effect on the bio chemistry of the biomass, but that these physio-chemical pre-treatments produced inhibitory compounds in the medium that retarded microbial growth. Attempts were made to genetically modified Bacillus subtilis 168 to…
Subjects/Keywords: Lignocellulose; Bacillus subtilis 168
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Munns, C. C. R. (2017). Development of physio-chemical pretreatments and mixed microbial cultures for the conversion of lignocellulosic biomass to useful products. (Doctoral Dissertation). University of Edinburgh. Retrieved from http://hdl.handle.net/1842/28768
Chicago Manual of Style (16th Edition):
Munns, Craig Christopher Robert. “Development of physio-chemical pretreatments and mixed microbial cultures for the conversion of lignocellulosic biomass to useful products.” 2017. Doctoral Dissertation, University of Edinburgh. Accessed April 13, 2021.
http://hdl.handle.net/1842/28768.
MLA Handbook (7th Edition):
Munns, Craig Christopher Robert. “Development of physio-chemical pretreatments and mixed microbial cultures for the conversion of lignocellulosic biomass to useful products.” 2017. Web. 13 Apr 2021.
Vancouver:
Munns CCR. Development of physio-chemical pretreatments and mixed microbial cultures for the conversion of lignocellulosic biomass to useful products. [Internet] [Doctoral dissertation]. University of Edinburgh; 2017. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1842/28768.
Council of Science Editors:
Munns CCR. Development of physio-chemical pretreatments and mixed microbial cultures for the conversion of lignocellulosic biomass to useful products. [Doctoral Dissertation]. University of Edinburgh; 2017. Available from: http://hdl.handle.net/1842/28768

University of Georgia
19.
Hawkins, Gary Matthew.
Development and characterization of a robust industrial yeast for high solids softwood fermentation using adaptation, directed evolution, and transcriptome profiling.
Degree: 2014, University of Georgia
URL: http://hdl.handle.net/10724/30466
► Currently almost all the fuel ethanol produced in the United States is generated from processes using corn as the feedstock. To increase production of ethanol,…
(more)
▼ Currently almost all the fuel ethanol produced in the United States is generated from processes using corn as the feedstock. To increase production of ethanol, other feedstocks must be developed as viable substrates for fermentation
processes. Efficient ethanol fermentation from softwood biomass, which is produced in large quantities globally, at titers suitable for an industrial process is challenging for a variety of reasons. One challenge is the generation of inhibitory compounds
from the biomass as it is pretreated prior to enzymatic digestion. These compounds are then present in the fermentation medium where they inhibit the activity of the fermenting organism. To overcome this bottleneck in softwood fermentation, we have
developed a Saccharomyces cerevisiae yeast strain that is capable of producing ethanol from greater than 17.5% dry weight per volume of pretreated softwood at ethanol yields over 90% of the theoretical maximum. This strain was developed from an
industrial corn ethanol yeast by adaptation and directed evolution in increasing concentrations of pretreated softwood. Isolates from the directed evolution experiments were screened for the inhibitor resistant phenotype and for the ability to ferment
pretreated softwood at high solids concentrations. Use of a model inhibitor medium for inoculum preparation enhanced fermentation performance with high solids concentrations of pretreated pine. When the inoculum was prepared for fermentation without the
inhibitors present in the medium, divergent phenotypes were observed. One set of isolates retained the ability to ferment high solids of pretreated pine regardless of the method used to prepare the inoculum, whereas another set of isolates displayed
reduced performance when the inhibitors were removed during inoculum preparation. Transcriptome profiling was used to characterize the gene expression patterns of a robust strain capable of fermentation of high softwood solids after preparation in either
media to a strain showing the divergent phenotype. Many expression differences were observed; including multiple changes not previously known to be related to inhibitor tolerance or high solids fermentation. Potential mechanisms by which the observed
expression differences aid in the robust strains’ performance in high softwood solids fermentations are presented.
Subjects/Keywords: Bioethanol; lignocellulose; Saccharomyces; transcriptomics; inhibitors
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
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APA (6th Edition):
Hawkins, G. M. (2014). Development and characterization of a robust industrial yeast for high solids softwood fermentation using adaptation, directed evolution, and transcriptome profiling. (Thesis). University of Georgia. Retrieved from http://hdl.handle.net/10724/30466
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Hawkins, Gary Matthew. “Development and characterization of a robust industrial yeast for high solids softwood fermentation using adaptation, directed evolution, and transcriptome profiling.” 2014. Thesis, University of Georgia. Accessed April 13, 2021.
http://hdl.handle.net/10724/30466.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Hawkins, Gary Matthew. “Development and characterization of a robust industrial yeast for high solids softwood fermentation using adaptation, directed evolution, and transcriptome profiling.” 2014. Web. 13 Apr 2021.
Vancouver:
Hawkins GM. Development and characterization of a robust industrial yeast for high solids softwood fermentation using adaptation, directed evolution, and transcriptome profiling. [Internet] [Thesis]. University of Georgia; 2014. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/10724/30466.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Hawkins GM. Development and characterization of a robust industrial yeast for high solids softwood fermentation using adaptation, directed evolution, and transcriptome profiling. [Thesis]. University of Georgia; 2014. Available from: http://hdl.handle.net/10724/30466
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Georgia
20.
Xia, Tian.
Fermentation of sugar mixtures found in lignocellulosic hydrolysate using substrate-selective Escherichia coli.
Degree: 2014, University of Georgia
URL: http://hdl.handle.net/10724/27359
► Substrate-selective uptake is a novel approach for the simultaneous consumption of sugars found in biomass hydrolysates. Of the five strains studied, E. coli W showed…
(more)
▼ Substrate-selective uptake is a novel approach for the simultaneous consumption of sugars found in biomass hydrolysates. Of the five strains studied, E. coli W showed generally the fastest growth on carbohydrates. The triple-knockout strain
W glk, ptsG manZ (KD777) consumed 7 g/L L-arabinose or D-xylose within 5.5 h, and subsequently consumed glucose only slowly. The presence of glucose did affect the utilization of D-galactose by KD777. Similar results were obtained with W glk, ptsG manZ
crr (KD915). Two-sugar carbon-limited chemostats with KD777 at a growth rate of 0.25 h-1 showed that including glucose in the feed slowed xylose, arabinose, galactose consumption by 8%, 20%, and 45% respectively. However, glucose was not consumed in the
presence of xylose.
Subjects/Keywords: Fermentation; Lignocellulose; Substrate-selective; Glucose
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Xia, T. (2014). Fermentation of sugar mixtures found in lignocellulosic hydrolysate using substrate-selective Escherichia coli. (Thesis). University of Georgia. Retrieved from http://hdl.handle.net/10724/27359
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Xia, Tian. “Fermentation of sugar mixtures found in lignocellulosic hydrolysate using substrate-selective Escherichia coli.” 2014. Thesis, University of Georgia. Accessed April 13, 2021.
http://hdl.handle.net/10724/27359.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Xia, Tian. “Fermentation of sugar mixtures found in lignocellulosic hydrolysate using substrate-selective Escherichia coli.” 2014. Web. 13 Apr 2021.
Vancouver:
Xia T. Fermentation of sugar mixtures found in lignocellulosic hydrolysate using substrate-selective Escherichia coli. [Internet] [Thesis]. University of Georgia; 2014. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/10724/27359.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Xia T. Fermentation of sugar mixtures found in lignocellulosic hydrolysate using substrate-selective Escherichia coli. [Thesis]. University of Georgia; 2014. Available from: http://hdl.handle.net/10724/27359
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Michigan State University
21.
McPherson, Nikolas Robin.
Novel insights into sugar and succinate metabolism of Actinobacillus succinogenes from strains evolved for improved growth on lignocellulose hydrolysate sugars.
Degree: 2017, Michigan State University
URL: http://etd.lib.msu.edu/islandora/object/etd:4688
► Thesis Ph. D. Michigan State University. Genetics 2017
A wide variety of industrially vital chemicals are currently produced from petroleum, using very well-refined processes and…
(more)
▼ Thesis Ph. D. Michigan State University. Genetics 2017
A wide variety of industrially vital chemicals are currently produced from petroleum, using very well-refined processes and a large industrial infrastructure. However, petroleum processing has a number of hazardous and otherwise negative impacts on the environment, as well as on human health. The supply and price of oil into the future are uncertain as well, and supplementing oil with feedstocks from renewable sources can help extend the current supply of oil and eventually replace it. Succinate is a specialty chemical currently produced from maleic anhydride from petroleum processing. If bio-based succinate could compete with the cost of maleic anhydride, it could replace maleic anhydride in a $15 billion commodity chemical market, taking advantage of the existing chemical production infrastructure. A major potential feedstock source for conversion to succinate is lignocellulose from agricultural waste or from bioenergy crops. The bacterium Actinobacillus succinogenes is one of the best natural succinate producers and it grows on a wide variety of carbohydrates, including the major sugars in lignocellulose. A. succinogenes grows well on glucose, the most common sugar in lignocellulose, but does not grow as quickly on other lignocellulosic sugars.I have evolved strains of A. succinogenes to grow faster on xylose, the second most common lignocellulosic sugar, as well as on arabinose, galactose, and lignocellulose hydrolysates. Many of the evolved strains produce more succinate than the parental strain as well, even though the evolution process did not specifically select for succinate production. The evolved strains were resequenced to identify the mutations accumulated during evolution. RNA sequencing of the xylose-evolved strains helped identify changes in transcript levels and was used to refine our conclusions about the xylose-evolved (X) strains. I discovered that the genes that encode many glycolytic enzymes were upregulated in at least one X strain, several genes encoding succinate production enzymes were upregulated, while genes that encode enzymes that redirect fluxes from the succinate pathway to other fermentation products were downregulated. During the directed evolution process, I obtained a strain of A. succinogenes that can grow on galactose, a sugar that the base strain cannot use. The final evolved strain grew faster than the wild-type strain on xylose, arabinose, and lignocellulose hydrolysate, and could grow on galactose. I determined that A. succinogenes will co-consume glucose and xylose, but that xylose represses arabinose consumption. After directed evolution, though, arabinose represses xylose consumption. Finally, I used multiplex transformation to introduce mutations from the evolved strains into the wild-type strain. The first strain produced, using the xylose symporter mutation from a xylose-evolved strain, produced 40% more succinate than wild-type A. succinogenes, even though it grew at less than half the speed. In summary, I have…
Advisors/Committee Members: Vieille, Claire, Reguera, Gemma, Shachar-Hill, Yair, Walton, Jonathan.
Subjects/Keywords: Actinobacillus – Genetics; Lignocellulose; Biocatalysis; Genetics
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
McPherson, N. R. (2017). Novel insights into sugar and succinate metabolism of Actinobacillus succinogenes from strains evolved for improved growth on lignocellulose hydrolysate sugars. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:4688
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
McPherson, Nikolas Robin. “Novel insights into sugar and succinate metabolism of Actinobacillus succinogenes from strains evolved for improved growth on lignocellulose hydrolysate sugars.” 2017. Thesis, Michigan State University. Accessed April 13, 2021.
http://etd.lib.msu.edu/islandora/object/etd:4688.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
McPherson, Nikolas Robin. “Novel insights into sugar and succinate metabolism of Actinobacillus succinogenes from strains evolved for improved growth on lignocellulose hydrolysate sugars.” 2017. Web. 13 Apr 2021.
Vancouver:
McPherson NR. Novel insights into sugar and succinate metabolism of Actinobacillus succinogenes from strains evolved for improved growth on lignocellulose hydrolysate sugars. [Internet] [Thesis]. Michigan State University; 2017. [cited 2021 Apr 13].
Available from: http://etd.lib.msu.edu/islandora/object/etd:4688.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
McPherson NR. Novel insights into sugar and succinate metabolism of Actinobacillus succinogenes from strains evolved for improved growth on lignocellulose hydrolysate sugars. [Thesis]. Michigan State University; 2017. Available from: http://etd.lib.msu.edu/islandora/object/etd:4688
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Aberdeen
22.
Zahedifar, Mojtaba.
Novel uses of lignin and hemicellulosic sugars from acid-hydrolysed lignocellulosic materials.
Degree: PhD, 1996, University of Aberdeen
URL: https://abdn.alma.exlibrisgroup.com/view/delivery/44ABE_INST/12153277370005941
;
https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342205
► Lignocellulosic materials (LM) are an ever present renewable and available energy source. The energy stored by photosynthesis in the form of vegetation is about ten…
(more)
▼ Lignocellulosic materials (LM) are an ever present renewable and available energy source. The energy stored by photosynthesis in the form of vegetation is about ten times more than world's annual energy consumption (Zsuffa, 1982). This source is the only alternative for chemical production after fossil fuels. Formation of organic acids (mainly acetic acid) from hemicellulose during steam treatment of LM leads to acid hydrolysis of cell wall components. Solubilization of hemicellulose and depolymerization of lignin are the most important changes that occur during the process. During hydrolysis of LM appreciable amounts of sugar degradation products, organic acids and phenolics are produced. Inhibitory effects of the compounds on yeast during alcoholic fermentation have been reported and several methods have been proposed to overcome the problem. Among the new compounds phenolics derived from lignin depolymerization have received most attention. Another problem during enzymic saccharification of cellulose is partial inactivation of cell free enzymes. The above mentioned constraints were investigated in this study.
Subjects/Keywords: 572.8; Lignocellulose
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
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Manager
APA (6th Edition):
Zahedifar, M. (1996). Novel uses of lignin and hemicellulosic sugars from acid-hydrolysed lignocellulosic materials. (Doctoral Dissertation). University of Aberdeen. Retrieved from https://abdn.alma.exlibrisgroup.com/view/delivery/44ABE_INST/12153277370005941 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342205
Chicago Manual of Style (16th Edition):
Zahedifar, Mojtaba. “Novel uses of lignin and hemicellulosic sugars from acid-hydrolysed lignocellulosic materials.” 1996. Doctoral Dissertation, University of Aberdeen. Accessed April 13, 2021.
https://abdn.alma.exlibrisgroup.com/view/delivery/44ABE_INST/12153277370005941 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342205.
MLA Handbook (7th Edition):
Zahedifar, Mojtaba. “Novel uses of lignin and hemicellulosic sugars from acid-hydrolysed lignocellulosic materials.” 1996. Web. 13 Apr 2021.
Vancouver:
Zahedifar M. Novel uses of lignin and hemicellulosic sugars from acid-hydrolysed lignocellulosic materials. [Internet] [Doctoral dissertation]. University of Aberdeen; 1996. [cited 2021 Apr 13].
Available from: https://abdn.alma.exlibrisgroup.com/view/delivery/44ABE_INST/12153277370005941 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342205.
Council of Science Editors:
Zahedifar M. Novel uses of lignin and hemicellulosic sugars from acid-hydrolysed lignocellulosic materials. [Doctoral Dissertation]. University of Aberdeen; 1996. Available from: https://abdn.alma.exlibrisgroup.com/view/delivery/44ABE_INST/12153277370005941 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342205

Ryerson University
23.
Al Jibouri, Ali Kamel H.
Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw.
Degree: 2012, Ryerson University
URL: https://digital.library.ryerson.ca/islandora/object/RULA%3A1185
► Wheat straw was pretreated with ozone to increase the enzymatic hydrolysis yield. Ozonolysis pretreatment was performed in two stages with an intermediate washing step with…
(more)
▼ Wheat straw was pretreated with ozone to increase the enzymatic hydrolysis yield. Ozonolysis pretreatment was performed in two stages with an intermediate washing step with water in between. Part of the delignification products (lignin fragments) were removed by a washing step so ozone was used to oxidize more lignin rather than oxidizing lignin fragments.Three parameters, i.e. Initial Water Content (IWC) in wheat straw, Washing Starting Time (WST), and Washing Contact Time (WCT), were optimized to minimize Acid Insoluble Lignin (AIL) content of ozonated wheat straw. Performing an experiment using optimal parameters' values, i.e. IWC equal to 45 wt. %, WST equal to 20 minutes and WCT equal to 80 seconds, showed a drop in AIL content to 9.35 % with an increase in enzymatic hydrolysis yield to 80 % of the theoretical. Readjusting water content of wheat straw to 45 % before performing the 2nd ozonolysis stage further reduced AIL content to 7.36 % and increased the hydrolysis yield to 90 %. Increasing wheat straw fiber size from < 2 mm to < 6 mm decreased the hydrolysis yield to 72 %. All results were considered significant improvements when compared to untreated wheat straw with AIL content of 20.5 % and hydrolysis yield of 23 %.
Advisors/Committee Members: Turcotte, Ginette (Thesis advisor), Wu, Jiangning (Thesis advisor), Cheng, Chil-Hung (Thesis advisor), Ryerson University (Degree grantor), Ryerson University (Degree grantor).
Subjects/Keywords: Ozonolysis; Straw as fuel; Hydrolysis; Lignocellulose
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Al Jibouri, A. K. H. (2012). Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw. (Thesis). Ryerson University. Retrieved from https://digital.library.ryerson.ca/islandora/object/RULA%3A1185
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Al Jibouri, Ali Kamel H. “Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw.” 2012. Thesis, Ryerson University. Accessed April 13, 2021.
https://digital.library.ryerson.ca/islandora/object/RULA%3A1185.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Al Jibouri, Ali Kamel H. “Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw.” 2012. Web. 13 Apr 2021.
Vancouver:
Al Jibouri AKH. Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw. [Internet] [Thesis]. Ryerson University; 2012. [cited 2021 Apr 13].
Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A1185.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Al Jibouri AKH. Effect of Intermediate Washing on Ozonolysis Delignification and Enzymatic Hydrolysis of Wheat Straw. [Thesis]. Ryerson University; 2012. Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A1185
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Ryerson University
24.
Dahahda, Samer.
Biological And Thermal Pretreatment Of Lignocellulosic Materials For Enhanced Biogas Production.
Degree: 2017, Ryerson University
URL: https://digital.library.ryerson.ca/islandora/object/RULA%3A7118
► The rapid depletion of natural resources and the environmental concerns associated with the use of fossil fuels as the main source of global energy is…
(more)
▼ The rapid depletion of natural resources and the environmental concerns associated with the use of fossil fuels as the main source of global energy is leading to an increased interest in alternative and renewable energy sources. Lignocellulosic biomass is the most abundant source of organic materials that can be utilized as an energy source. Anaerobic digestion has been proven to be an effective technology for converting organic material into energy products such as biogas. However, the nature of lignocellulosic materials hinders the ability of microorganisms in an anaerobic digestion process to degrade and convert organic material to biogas. Therefore, a pretreatment step is necessary to improve the degradability of lignocellulosic materials and achieve higher biogas yield. Several pretreatment methods have been studied over the past few years including physical, thermal, chemical and biological pretreatment. This paper reviews biological and thermal pretreatment as two main promising methods used to improve biogas production from lignocelluloses. A greater focus is given on enzymatic pretreatment which is one of the promising yet under-researched biological pretreatment method. The paper addresses challenges in degrading lignocellulosic materials and the current status of research to improve biogas yield from lignocelluloses through biological and thermal pretreatment.
Subjects/Keywords: Biogas; Biodegradation; Renewable energy sources; Lignocellulose – Biodegradation
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APA ·
Chicago ·
MLA ·
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CSE |
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APA (6th Edition):
Dahahda, S. (2017). Biological And Thermal Pretreatment Of Lignocellulosic Materials For Enhanced Biogas Production. (Thesis). Ryerson University. Retrieved from https://digital.library.ryerson.ca/islandora/object/RULA%3A7118
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Dahahda, Samer. “Biological And Thermal Pretreatment Of Lignocellulosic Materials For Enhanced Biogas Production.” 2017. Thesis, Ryerson University. Accessed April 13, 2021.
https://digital.library.ryerson.ca/islandora/object/RULA%3A7118.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Dahahda, Samer. “Biological And Thermal Pretreatment Of Lignocellulosic Materials For Enhanced Biogas Production.” 2017. Web. 13 Apr 2021.
Vancouver:
Dahahda S. Biological And Thermal Pretreatment Of Lignocellulosic Materials For Enhanced Biogas Production. [Internet] [Thesis]. Ryerson University; 2017. [cited 2021 Apr 13].
Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A7118.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Dahahda S. Biological And Thermal Pretreatment Of Lignocellulosic Materials For Enhanced Biogas Production. [Thesis]. Ryerson University; 2017. Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A7118
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Ryerson University
25.
Dumitrache, Alexandru.
Description Of Associative Behaviour During Microbial Cellulose Utilization By Clostridium Thermocellum For Application In Advanced Biomass Conversion Process Development.
Degree: 2009, Ryerson University
URL: https://digital.library.ryerson.ca/islandora/object/RULA%3A1706
► Recent findings support the concept that Clostridium thermocellum is a cellulose-utilizing specialist having growth benefits with increasing substrate chain length. We developed a continuous-flow system…
(more)
▼ Recent findings support the concept that Clostridium thermocellum is a cellulose-utilizing specialist having growth benefits with increasing substrate chain length. We developed a continuous-flow system for in-situ detection of cellulose colonization and qualitatively assayed metabolic activities and behaviour of cellulolytic cultures. This study demonstrates the existence of strongly adherent celluloytic cells arranged in monolayers with invariably end-on attached spores. The substrate-cell distance was recorded to be lower than 0.44 pm and a typical EPS matrix was absent. Measurements on carbon dioxide released in continuous-flow cultures was successfully employed to monitor biofilm activity and total carbohydrate assays do not reveal loss of cellulolysis end-products in the effluent. These findings demonstrate the bacteria have optimized access to the cellulosic substrates and suggest that they have an ability to sequester products of substrate hydrolysis which confers benefits over non-adherent cellulolytic or non-cellulolytic organisms.
Advisors/Committee Members: Wolfaardt, Gideon M. (Thesis advisor), Lynd, Lee R. (Thesis advisor), Ryerson University (Degree grantor).
Subjects/Keywords: Biomass energy; Biomass conversion; Lignocellulose – Biotechnology
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APA ·
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MLA ·
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APA (6th Edition):
Dumitrache, A. (2009). Description Of Associative Behaviour During Microbial Cellulose Utilization By Clostridium Thermocellum For Application In Advanced Biomass Conversion Process Development. (Thesis). Ryerson University. Retrieved from https://digital.library.ryerson.ca/islandora/object/RULA%3A1706
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Dumitrache, Alexandru. “Description Of Associative Behaviour During Microbial Cellulose Utilization By Clostridium Thermocellum For Application In Advanced Biomass Conversion Process Development.” 2009. Thesis, Ryerson University. Accessed April 13, 2021.
https://digital.library.ryerson.ca/islandora/object/RULA%3A1706.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Dumitrache, Alexandru. “Description Of Associative Behaviour During Microbial Cellulose Utilization By Clostridium Thermocellum For Application In Advanced Biomass Conversion Process Development.” 2009. Web. 13 Apr 2021.
Vancouver:
Dumitrache A. Description Of Associative Behaviour During Microbial Cellulose Utilization By Clostridium Thermocellum For Application In Advanced Biomass Conversion Process Development. [Internet] [Thesis]. Ryerson University; 2009. [cited 2021 Apr 13].
Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A1706.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Dumitrache A. Description Of Associative Behaviour During Microbial Cellulose Utilization By Clostridium Thermocellum For Application In Advanced Biomass Conversion Process Development. [Thesis]. Ryerson University; 2009. Available from: https://digital.library.ryerson.ca/islandora/object/RULA%3A1706
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University
26.
Zuroff, Trevor Roman.
Engineering a microbial consortium for lignocellulosic biofuel production.
Degree: 2014, Penn State University
URL: https://submit-etda.libraries.psu.edu/catalog/22540
► Lignocellulose represents an abundant, renewable resource for the production of liquid transportation fuels to fulfill the energy demand of a growing, developing global population. However,…
(more)
▼ Lignocellulose represents an abundant, renewable resource for the production of liquid transportation fuels to fulfill the energy demand of a growing, developing global population. However, the recalcitrant nature of the biomaterial has perplexed scientists for decades; lignocellulosic fuels still cost two to five times more to produce than their petroleum-derived counterparts. A novel class of bioprocess designs are necessary to overcome the costs associated with conversion of this obstinate feedstock. An intensified processing scheme, termed consolidated bioprocessing, was touted as an economically feasible bioprocessing strategy where consolidation of processing steps was thought to enhance both process and economic efficiencies. Yet no single organism has been discovered or engineered that is capable of efficient consolidated bioprocessing. On the other hand, nature executes what may be the ultimate consolidated bioprocess through conversion of plant material to carbon dioxide and methane as part of the global carbon cycle. The concerted action of numerous naturally-occurring microorganisms overcomes many of the issues encountered in industrial, single-organism
lignocellulose bioprocessing. In this dissertation, based on a nature-inspired design, a two-member microbial consortium was developed for the conversion of cellulose to fuel. Cooperation is induced between the cellulolytic, anaerobic bacterium Clostridium phytofermentans and Saccharomyces cerevisiae via oxygen diffusion, controlling consortium populations and promoting fuel production. S. cerevisiae consumes oxygen to protect C. phytofermentans which in return degrades cellulose providing soluble carbon for the yeast. This symbiotic design improves ethanol and/or hydrocarbon production from purified cellulose over two-fold. Detailed analyses of C. phytofermentans biofilm formation and fermentation characteristics revealed that glucose and ethanol are robust inhibitors of C. phytofermentans surface attachment and growth, respectively. Ethanol tolerance was improved via strain evolution and metabolic engineering was applied to overcome an adaptive reduction in ethanol yield. Finally, a comprehensive mathematical framework was developed to model the consortium and provide insight into the intricate cooperation toward improving system productivity. In summary, inspired by naturally occurring microbial ecosystems, this dissertation describes the application of scientific and engineering principles to improve the viability of microbial consortia for industrial-scale conversion of lignocellulosic biomass to fuel.
Advisors/Committee Members: Wayne Roger Curtis, Dissertation Advisor/Co-Advisor, Howard M Salis, Committee Member, Thomas Keith Wood, Committee Member, Katriona Shea, Committee Member, Manish Kumar, Committee Member.
Subjects/Keywords: Lignocellulose; biofuels; Clostridium phytofermentans; cellulose; microbial consortia
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zuroff, T. R. (2014). Engineering a microbial consortium for lignocellulosic biofuel production. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/22540
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Zuroff, Trevor Roman. “Engineering a microbial consortium for lignocellulosic biofuel production.” 2014. Thesis, Penn State University. Accessed April 13, 2021.
https://submit-etda.libraries.psu.edu/catalog/22540.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Zuroff, Trevor Roman. “Engineering a microbial consortium for lignocellulosic biofuel production.” 2014. Web. 13 Apr 2021.
Vancouver:
Zuroff TR. Engineering a microbial consortium for lignocellulosic biofuel production. [Internet] [Thesis]. Penn State University; 2014. [cited 2021 Apr 13].
Available from: https://submit-etda.libraries.psu.edu/catalog/22540.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Zuroff TR. Engineering a microbial consortium for lignocellulosic biofuel production. [Thesis]. Penn State University; 2014. Available from: https://submit-etda.libraries.psu.edu/catalog/22540
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
27.
Brzonova, Ivana.
Biodegradation And Biomodification Of Lignocellulose With A Main Focus On Lignin.
Degree: PhD, Chemical Engineering, 2017, University of North Dakota
URL: https://commons.und.edu/theses/2180
► Lignin is the second most abundant biopolymer, and the first most abundant source of phenolic structures, on Earth. Recent research has focused on lignin…
(more)
▼ Lignin is the second most abundant biopolymer, and the first most abundant source of phenolic structures, on Earth. Recent research has focused on lignin monomers as replacements for phenolic monomers derived from nonrenewable resources. Biological decomposition and conversion may be one way to accomplish this objective. In this study, the effects of two basidiomycetous fungi (Coriolus versicolor and Trametes gallica) and two actinobacteria strains (Microbacterium sp. and Streptomyces sp.) and their combination on
lignocellulose (kenaf) decomposition was evaluated.
The results showed that after 8 weeks of incubation up to 34 wt. % of the kenaf biomass was degraded, and the combination of fungi and bacteria was the most efficient. Lignin decomposition accounted for ~ 20 wt. % of the observed biomass reduction, regardless of the culture used. Most of this lignin was present as solubilized oligomers rather than monomers. Only after the monosaccharides were utilized by the microorganisms was the production of laccase, manganese-dependent peroxidase and lignin peroxidase enzymes induced, allowing lignin degradation to commence. The presence of carbohydrates was found to be detrimental for lignin degradation.
In a subsequent series of experiments, we targeted the degradation/modification of isolated industrial-kraft lignin while trying to reduce the process time by solubilizing lignin with DMSO to increase lignin availability for enzymes. The addition of 2 vol% DMSO to nutrient free aqueous media increased the lignin solubility up to 70% while the quasi-immobilized fungi (pre-grown on agar) maintained their ability to produce lignolytic enzymes. While biological treatment was done for 6 days, significant modification was already observed in less than 24 hours. The resulting product showed the removal of phenolic monomers and/or their immediate precursors and a significant intramolecular cross-linking among the reaction products. Thus a new path for lignin biotreatment and further utilization was observed leading to the formation of polymers rather than monomers.
Our interest therefore shifted to lignin utilization as a biochemically modified macromolecule. The biologically modified lignin was isolated via two different paths: 1) precipitation by acidification followed by washing with water or alcohols, or 2) vacuum evaporation followed by drying. The results of novel detailed chemical analysis of the modified lignin polymers showed that each of the washing steps can be used as a modification process, since each of them produced a slightly different polymer, with varied thermal stability, swelling and buffer capacities.
The resulting lignin based polymers turned out to be insoluble in either organic solvents such as DMSO, DMF, NMP, dioxane etc., or in water. However, under alkaline conditions (1M NaOH) all of these new polymers were converted into pH sensitive anionic-hydrogels showing remarkable thermal stability and varied sulfur content, which,…
Advisors/Committee Members: Yun Ji.
Subjects/Keywords: basidiomycetes; bioconversion; biomodification; hydrogels; lignin; lignocellulose
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Brzonova, I. (2017). Biodegradation And Biomodification Of Lignocellulose With A Main Focus On Lignin. (Doctoral Dissertation). University of North Dakota. Retrieved from https://commons.und.edu/theses/2180
Chicago Manual of Style (16th Edition):
Brzonova, Ivana. “Biodegradation And Biomodification Of Lignocellulose With A Main Focus On Lignin.” 2017. Doctoral Dissertation, University of North Dakota. Accessed April 13, 2021.
https://commons.und.edu/theses/2180.
MLA Handbook (7th Edition):
Brzonova, Ivana. “Biodegradation And Biomodification Of Lignocellulose With A Main Focus On Lignin.” 2017. Web. 13 Apr 2021.
Vancouver:
Brzonova I. Biodegradation And Biomodification Of Lignocellulose With A Main Focus On Lignin. [Internet] [Doctoral dissertation]. University of North Dakota; 2017. [cited 2021 Apr 13].
Available from: https://commons.und.edu/theses/2180.
Council of Science Editors:
Brzonova I. Biodegradation And Biomodification Of Lignocellulose With A Main Focus On Lignin. [Doctoral Dissertation]. University of North Dakota; 2017. Available from: https://commons.und.edu/theses/2180

Rhodes University
28.
Clarke, Matthew David.
Biochemical characterization of the β-mannanase activity of Bacillus paralicheniformis SVD1.
Degree: Faculty of Science, Biochemistry and Microbiology, 2019, Rhodes University
URL: http://hdl.handle.net/10962/67570
► Products produced via the enzymatic hydrolysis of lignocellulosic biomass, the most abundant renewable terrestrial source of carbon, can potentially replace a lot of the fuels…
(more)
▼ Products produced via the enzymatic hydrolysis of lignocellulosic biomass, the most abundant renewable terrestrial source of carbon, can potentially replace a lot of the fuels and chemicals currently produced using non-renewable hydrocarbons. Mannan is a polysaccharide component of lignocellulose that is abundant in softwoods and legume seeds. Enzymatic hydrolysis of mannan by β-mannanases has various industrial applications, including use in biofuel and prebiotic mannooligosaccharide (MOS) production for the improvement of human and animal health. The industrial use of β-mannanases depends on their biochemical characteristics, such as their activity, stability and substrate specificity. Knowledge of their synergistic interactions with other enzymes is also useful for effective hydrolysis. Bacillus paralicheniformis SVD1 was used as a source for β-mannanases. The two mannanases of B. paralicheniformis SVD1 have not been biochemically characterized apart from minor characterization of crude β-mannanase activity. The protein sequences of the two β-mannanases, of glycosyl hydrolase family 5 and 26, have a 95% - 96% identity to the β-mannanases of B. licheniformis DSM13T (=ATCC14580T). These small protein sequence differences could lead to quite different biochemical characteristics. These mannanases were characterized as these enzymes may have industrially useful characteristics. To induce mannanase production, B. paralicheniformis SVD1 was cultured in broth containing the mannan substrate locust bean gum. Various growth curve parameters were measured over 72 h. Mannanase activity was the highest after 48 h of growth - this was the time at which mannanase activity was concentrated, using 3 kDa centrifugal filtration devices, for biochemical characterization of the crude activity. Zymography revealed that the crude concentrated mannanase fraction consisted of at least two mannanases with relative molecular weights (MWs) of 29.6 kDa and 33 kDa. This was smaller than expected – based on their theoretical molecular masses. Protease activity, which was detected in the broth, was probably the reason. There were two pH optima, pH 5.0 and pH 7.0, which also indicated the presence of two mannanases. The concentrated mannanase displayed characteristics that were expected of a B. paralicheniformis β-mannanase. The temperature optimum was 50°C and the activity loss was less than 7% at 50°C after 24 h. Substrate specificity assays revealed that there was predominantly mannanase activity present. Thin layer chromatography (TLC) analysis of mannan and MOS hydrolysis showed that mainly M2 and M3 MOS were produced; only MOS with a degree of polymerization of 4 or higher were hydrolyzed. Hydrolysis was minimal on mannoligosaccharides with galactose substituents. Activity and MOS production was the highest on soluble, low branched mannan substrates. The highest activity observed was on konjac glucomannan. Purification of the mannanase activity was then attempted using various methods. Ammonium sulfate precipitation, acetone precipitation,…
Subjects/Keywords: Mycobacterium avium paratuberculosis; Enzymes – Biotechnology; Lignocellulose – Biotechnology
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Clarke, M. D. (2019). Biochemical characterization of the β-mannanase activity of Bacillus paralicheniformis SVD1. (Thesis). Rhodes University. Retrieved from http://hdl.handle.net/10962/67570
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Clarke, Matthew David. “Biochemical characterization of the β-mannanase activity of Bacillus paralicheniformis SVD1.” 2019. Thesis, Rhodes University. Accessed April 13, 2021.
http://hdl.handle.net/10962/67570.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Clarke, Matthew David. “Biochemical characterization of the β-mannanase activity of Bacillus paralicheniformis SVD1.” 2019. Web. 13 Apr 2021.
Vancouver:
Clarke MD. Biochemical characterization of the β-mannanase activity of Bacillus paralicheniformis SVD1. [Internet] [Thesis]. Rhodes University; 2019. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/10962/67570.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Clarke MD. Biochemical characterization of the β-mannanase activity of Bacillus paralicheniformis SVD1. [Thesis]. Rhodes University; 2019. Available from: http://hdl.handle.net/10962/67570
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Oregon State University
29.
Zauscher, Stefan.
Orienting lignocellulosic fibers by means of a magnetic field.
Degree: MS, Materials Science, 1992, Oregon State University
URL: http://hdl.handle.net/1957/36066
► Controlling the orientation and spatial distribution of discontinuous fibers in composite materials enables product properties to be tailored to anticipated use. Electric fields are already…
(more)
▼ Controlling the orientation and spatial distribution of
discontinuous fibers in composite materials enables product
properties to be tailored to anticipated use. Electric
fields are already (albeit rarely) used to affect alignment
in lignocellulosic (LC) fiber composites. The use of
magnetic fields has not, however, been suggested or
explored; this is apparently because LC fibers are
essentially non-magnetic. The approach may offer, however,
some considerable advantages, as long as ferromagnetism may
be imparted to the fibers.
In the present research several fiber modification
processes were considered and two, electroless nickel
plating and spray application of a coating containing nickel
in suspension, were investigated in more depth. The latter
was chosen to render highly engineered, elongated wood
particles responsive to magnetic fields. Individual treated
particles were suspended in viscous, newtonian silicone
fluids and their rotation under the influence of a
controlled magnetic field was video recorded.
The magnetic torque on the particle was, under the
above conditions, directly proportional to the fluid
viscosity, to the particle's angular velocity and to a
characteristic shape constant. The maximum of the specific
magnetic torque (magnetic torque divided by the shape
constant) was found to reflect the influence of field
strength and particle Ni-treatment on rotation. Results
were scaled to an arbitrarily chosen viscosity for
comparison.
The dependencies of the magnetic torque found in the
present research compare with those theoretically predicted
for ellipsoidal and cylindrical bodies. For field strengths
ranging from 0.07T to 0.15T (below magnetic saturation) the
magnetic torque increased almost linearly with increasing
field strength. Magnetic torque was also found to increase
nearly linearly with increasing bulk Ni-concentration (5g/kg
- 50g/kg).
Rotational motion was sometimes impeded at low field
strengths and this was attributed to a permanent magnetic
moment obtained by the particle. A coercive field strength
of 7600A/m supported this hypothesis. Judiciously switched
field polarity increased magnetic torque at small alignment
angles.
The present research indicates that orienting LC fibers
with magnetic fields is possible and promising. To study
dynamics of fiber motion in low viscosity fluids, such as
air, a different experimental method is necessary; however,
dependencies of the magnetic torque found in the present
study still hold true.
Advisors/Committee Members: Humphrey, Philip E. (advisor).
Subjects/Keywords: Lignocellulose – Magnetic properties
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zauscher, S. (1992). Orienting lignocellulosic fibers by means of a magnetic field. (Masters Thesis). Oregon State University. Retrieved from http://hdl.handle.net/1957/36066
Chicago Manual of Style (16th Edition):
Zauscher, Stefan. “Orienting lignocellulosic fibers by means of a magnetic field.” 1992. Masters Thesis, Oregon State University. Accessed April 13, 2021.
http://hdl.handle.net/1957/36066.
MLA Handbook (7th Edition):
Zauscher, Stefan. “Orienting lignocellulosic fibers by means of a magnetic field.” 1992. Web. 13 Apr 2021.
Vancouver:
Zauscher S. Orienting lignocellulosic fibers by means of a magnetic field. [Internet] [Masters thesis]. Oregon State University; 1992. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1957/36066.
Council of Science Editors:
Zauscher S. Orienting lignocellulosic fibers by means of a magnetic field. [Masters Thesis]. Oregon State University; 1992. Available from: http://hdl.handle.net/1957/36066

Swedish University of Agricultural Sciences
30.
Liu, Bing.
Dissecting function and catalytic mechanism of fungal lytic polysaccharide monooxygenases.
Degree: 2019, Swedish University of Agricultural Sciences
URL: https://pub.epsilon.slu.se/16247/
► Fungi use a complex and well-orchestrated enzyme machinery to degrade lignocellulose biomass, in which both hydrolytic and redox enzymes are involved. Lytic polysaccharide monoxygenases (LPMOs)…
(more)
▼ Fungi use a complex and well-orchestrated enzyme machinery to degrade lignocellulose biomass, in which both hydrolytic and redox enzymes are involved. Lytic polysaccharide monoxygenases (LPMOs) are copper-dependent enzymes that cleave bonds in polysaccharides using oxidative mechanisms. LPMOs belonging to auxiliary activity family 9 (AA9) are widely distributed in the fungal kingdom. The aim of this study is to develop a better understanding of the roles of AA9 LPMOs in lignocellulose degradation with the focus on a white-rot softwood-decaying fungus Heterobasidion irregulare as well as to gain more insights into their catalytic mechanism by investigating the interaction of C1-specific AA9 LPMOs with substrate/co-substrate at molecular level. Two LPMOs from H. irregulare (HiLPMO9H and HiLPMO9I) were shown to have different substrate specificity against cellulose and glucomannan, indicating that AA9 LPMOs may be involved in degradation of different plant cell wall components during the decay of softwood by the H. irregulare (Paper I). Another H. irregulare LPMO (HiLPMO9B) was found to increase the substrate accessibility for a homologous cellobiohydrolase (HiCel7A) and the cooperation between these two enzymes were shown during crystalline cellulose degradation, indicating that AA9 LPMO may act in synergy with cellulases as importance members in the cellulose degradation system of H. irregulare (Paper II). Molecular dynamics showed that the C1-specific HiLPMO9B uses acidic residues to bind onto the cellulose surface in addition to hydrophobic residues (Paper III). Furthermore, it was shown that cyanide inhibits the activity of the C1-specific PcLPMO9D by competing with O2 binding to the enzyme. Cyanide was shown to bind to the axial position of copper coordinating sites, reflecting a possible scenario of the proposed Cu-superoxyl intermediate (Paper IV). The present study has increased our understanding of the functionalization of LPMO in basidiomycete fungi and has expanded the current view on possible substrate/co-substrate interaction at molecular level.
Subjects/Keywords: lignocellulose; fungi; LPMO; biological role; catalytic mechanism
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Liu, B. (2019). Dissecting function and catalytic mechanism of fungal lytic polysaccharide monooxygenases. (Doctoral Dissertation). Swedish University of Agricultural Sciences. Retrieved from https://pub.epsilon.slu.se/16247/
Chicago Manual of Style (16th Edition):
Liu, Bing. “Dissecting function and catalytic mechanism of fungal lytic polysaccharide monooxygenases.” 2019. Doctoral Dissertation, Swedish University of Agricultural Sciences. Accessed April 13, 2021.
https://pub.epsilon.slu.se/16247/.
MLA Handbook (7th Edition):
Liu, Bing. “Dissecting function and catalytic mechanism of fungal lytic polysaccharide monooxygenases.” 2019. Web. 13 Apr 2021.
Vancouver:
Liu B. Dissecting function and catalytic mechanism of fungal lytic polysaccharide monooxygenases. [Internet] [Doctoral dissertation]. Swedish University of Agricultural Sciences; 2019. [cited 2021 Apr 13].
Available from: https://pub.epsilon.slu.se/16247/.
Council of Science Editors:
Liu B. Dissecting function and catalytic mechanism of fungal lytic polysaccharide monooxygenases. [Doctoral Dissertation]. Swedish University of Agricultural Sciences; 2019. Available from: https://pub.epsilon.slu.se/16247/
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