+publisher:"Virginia Tech" +contributor:("Zhang, Chenming Mike")

Virginia Tech

1. Babahosseini, Hesam. Nanoparticle-Based Drug Delivery and the Impacts on Cancer Cell Biophysical Markers.

Degree: MS, Biological Systems Engineering, 2015, Virginia Tech

► Cancer progression and physiological changes within the cells are accompanied by alterations in the biophysical properties. Therefore, the cell biophysical properties can serve as promising… (more)

▼ Cancer progression and physiological changes within the cells are accompanied by alterations in the biophysical properties. Therefore, the cell biophysical properties can serve as promising markers for cancer detection and physiological activities. To aid in the investigation of the biophysical markers of cells, a microfluidic chip has been developed which consists of a constriction channel and embedded microelectrodes. Single-cell impedance magnitudes at four frequencies and entry and travel times are measured simultaneously during their transit through the constriction channel. This microchip provides a high-throughput, label-free, automated assay to define biophysical signatures of malignant cells and monitor the therapeutic efficacy of drugs. Here, we monitored the dynamic cellular biophysical markers in response to sphingosine kinase inhibitors (SphKIs), and compared the effectiveness of drug delivery using Poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with SphKIs versus conventional delivery. Cells treated with SphKIs showed significantly higher impedance magnitudes at all four frequencies. The bioelectrical parameters extracted using a model also revealed that the highly aggressive breast cells treated with SphKIs shifted electrically towards that of a less malignant phenotype; SphKI-treated cells exhibited an increase in cell-channel interface resistance and a significant decrease in specific membrane capacitance. Furthermore, SphKI-treated cells became slightly more deformable as measured by a decrease in their channel entry and travel times. We observed no significant difference in the bioelectrical changes produced by SphKI delivered conventionally or with NPs. However, NPs-packaged delivery of SphKI decreased the cell deformability. In summary, the results showed that while the bioelectrical properties of the cells were dominantly affected by SphKIs, the biomechanical properties were mainly changed by the NPs. Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Santos, Webster (committee member), Agah, Masoud (committeecochair).

Subjects/Keywords: MicroElectroMechanical Systems (MEMS); Microfluidics; Biosensor; Nanoparticles; Drug Delivery; Biomechanics; Bioelectronics; Breast Cancer; MDA-MB-231; Sphingosine Kinase Inhibitors

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APA (6^th Edition):

Babahosseini, H. (2015). Nanoparticle-Based Drug Delivery and the Impacts on Cancer Cell Biophysical Markers. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/79689

Chicago Manual of Style (16^th Edition):

Babahosseini, Hesam. “Nanoparticle-Based Drug Delivery and the Impacts on Cancer Cell Biophysical Markers.” 2015. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/79689.

MLA Handbook (7^th Edition):

Babahosseini, Hesam. “Nanoparticle-Based Drug Delivery and the Impacts on Cancer Cell Biophysical Markers.” 2015. Web. 18 Jan 2021.

Vancouver:

Babahosseini H. Nanoparticle-Based Drug Delivery and the Impacts on Cancer Cell Biophysical Markers. [Internet] [Masters thesis]. Virginia Tech; 2015. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/79689.

Council of Science Editors:

Babahosseini H. Nanoparticle-Based Drug Delivery and the Impacts on Cancer Cell Biophysical Markers. [Masters Thesis]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/79689

Virginia Tech

2. Venkatesh Murthy, Ambika Mosale. Virus-like particles as a vaccine against porcine reproductive and respiratory syndrome virus.

Degree: MS, Biological Systems Engineering, 2013, Virginia Tech

URL: http://hdl.handle.net/10919/50974

► Porcine reproductive and respiratory syndrome (PRRS) is the most significant infectious disease currently affecting the swine industry worldwide. Several inactivated and modified live vaccines (MLV)… (more)

Subjects/Keywords: Porcine reproductive and respiratory syndrome virus; PRRSV; vaccine; VLP; inclusion bodies

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APA (6^th Edition):

Venkatesh Murthy, A. M. (2013). Virus-like particles as a vaccine against porcine reproductive and respiratory syndrome virus. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/50974

Chicago Manual of Style (16^th Edition):

Venkatesh Murthy, Ambika Mosale. “Virus-like particles as a vaccine against porcine reproductive and respiratory syndrome virus.” 2013. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/50974.

MLA Handbook (7^th Edition):

Venkatesh Murthy, Ambika Mosale. “Virus-like particles as a vaccine against porcine reproductive and respiratory syndrome virus.” 2013. Web. 18 Jan 2021.

Vancouver:

Venkatesh Murthy AM. Virus-like particles as a vaccine against porcine reproductive and respiratory syndrome virus. [Internet] [Masters thesis]. Virginia Tech; 2013. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/50974.

Council of Science Editors:

Venkatesh Murthy AM. Virus-like particles as a vaccine against porcine reproductive and respiratory syndrome virus. [Masters Thesis]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/50974

Virginia Tech

3. Fulton, Andrew Dale. Monoclonal Antibody Expression and Novel Purification in Nicotiana benthamiana.

Degree: MS, Biological Systems Engineering, 2011, Virginia Tech

URL: http://hdl.handle.net/10919/43361

► Over the past few decades researchers and industrial professionals alike have realized the vast potential of monoclonal antibodies to treat diseases ranging from arthritis, immune… (more)

▼ Over the past few decades researchers and industrial professionals alike have realized the vast potential of monoclonal antibodies to treat diseases ranging from arthritis, immune and infectious diseases to cancer. There are a number of antibodies on the market that constitute a large portion of the biopharmaceutical niche in the drug industry. Blockbuster drugs (selling greater than $1 billion/year), include antibodies such as Avastin (bevacizumab), Herceptin (trastuzumab), Rituxan (rituximab), Humira (adalimumab) and Remicade (infliximab), which are cornerstones in this type of sector. With the cost of development to market approval rising astronomically for a new drug, new ways to produce and process these molecules becomes a paramount objective to ultimately help both patients and drug developers. Plants, such as Nicotiana benthamiana, offer a unique production platform due to their recently found ability to produce large amounts of therapeutic proteins in a quick manner. While production would be simple and cheap, purification would not be due to the presence of toxic compounds in ground plant tissue. The current methods to purify these molecules from plant extract include expensive affinity column steps (Protein A/G) that are difficult to scale-up to bed volumes that would be necessary for this technology. In the following paper, a method to purify a monoclonal antibody by non-Protein A/G resins is accomplished and compared to purification by Protein A. The modified process involved an UF/DF step, a precipitation of native impurities step using a charged polymer, hydrophobic interaction chromatography and hydrophobic charge induction chromatography. The yield of this modified process was 19.0%. This process compared favorably with Protein A due to the fact that even with washing steps including NaCl and Tween-20, the Protein A elution fraction still contained a large portion of host cell impurities. A chromatography step would need to be included before Protein A to both protect the column resin and provide a more purified immunoglobulin. Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Senger, Ryan S. (committee member), Whittington, Abby R. (committee member).

Subjects/Keywords: Ebola virus; monoclonal antibodies; MEP HyperCelTM; transgenic plants; antibody purification; Protein A

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APA (6^th Edition):

Fulton, A. D. (2011). Monoclonal Antibody Expression and Novel Purification in Nicotiana benthamiana. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/43361

Chicago Manual of Style (16^th Edition):

Fulton, Andrew Dale. “Monoclonal Antibody Expression and Novel Purification in Nicotiana benthamiana.” 2011. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/43361.

MLA Handbook (7^th Edition):

Fulton, Andrew Dale. “Monoclonal Antibody Expression and Novel Purification in Nicotiana benthamiana.” 2011. Web. 18 Jan 2021.

Vancouver:

Fulton AD. Monoclonal Antibody Expression and Novel Purification in Nicotiana benthamiana. [Internet] [Masters thesis]. Virginia Tech; 2011. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/43361.

Council of Science Editors:

Fulton AD. Monoclonal Antibody Expression and Novel Purification in Nicotiana benthamiana. [Masters Thesis]. Virginia Tech; 2011. Available from: http://hdl.handle.net/10919/43361

Virginia Tech

4. Colandro, Michelle Elizabeth. Baculovirus stability in serum-free lyophilized and wet storage conditions.

Degree: MS, Biological Systems Engineering, 2013, Virginia Tech

URL: http://hdl.handle.net/10919/51596

► The baculovirus expression vector system (BEVS) is an effective way to produce recombinant proteins for biopharmaceuticals. However baculovirus stocks are stored in subzero temperatures to… (more)

Subjects/Keywords: baculovirus protein expression system; stability; storage; lyophilization

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APA (6^th Edition):

Colandro, M. E. (2013). Baculovirus stability in serum-free lyophilized and wet storage conditions. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/51596

Chicago Manual of Style (16^th Edition):

Colandro, Michelle Elizabeth. “Baculovirus stability in serum-free lyophilized and wet storage conditions.” 2013. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/51596.

MLA Handbook (7^th Edition):

Colandro, Michelle Elizabeth. “Baculovirus stability in serum-free lyophilized and wet storage conditions.” 2013. Web. 18 Jan 2021.

Vancouver:

Colandro ME. Baculovirus stability in serum-free lyophilized and wet storage conditions. [Internet] [Masters thesis]. Virginia Tech; 2013. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/51596.

Council of Science Editors:

Colandro ME. Baculovirus stability in serum-free lyophilized and wet storage conditions. [Masters Thesis]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/51596

Virginia Tech

5. Sun, Fangfang. Development of Building Blocks - Thermostable Enzymes for Synthetic Pathway Biotransformation (SyPaB).

Degree: MS, Biological Systems Engineering, 2012, Virginia Tech

URL: http://hdl.handle.net/10919/77009

► Hydrogen production from abundant renewable biomass would decrease reliance on crude oils, achieve nearly zero net greenhouse gas emissions, create more jobs, and enhance national… (more)

▼ Hydrogen production from abundant renewable biomass would decrease reliance on crude oils, achieve nearly zero net greenhouse gas emissions, create more jobs, and enhance national energy security. Cell-free synthetic pathway biotransformation (SyPaB) is the implementation of complicated chemical reaction by the in vitro assembly of numerous enzymes and coenzymes that microbes cannot do. One of the largest challenges is the high cost and instability of enzymes and cofactors. To overcome this obstacle, strong motivations have driven intensive efforts in discovering, engineering, and producing thermostable enzymes. In this project, ribose-5-phosphate isomerase (RpiB), one of the most important enzymes in the pentose phosphate pathway, was cloned from a thermophile Thermotoga maritima, and heterologously expressed in Escherichia coli, purified and characterized. High-purity RpiB was obtained by heat pretreatment through its optimization in buffer choice, buffer pH, as well as temperature and duration of pretreatment. This enzyme had the maximum activity at 80°C and pH 6.5-8.0. It had a half lifetime of 71 h at 60°C, resulting in its turn-over number of more than 2 x108 mol of product per mol of enzyme. Another two thermostable enzymes glucose-6-phosphate dehydrogenase (G6PDH) and diaphorase (DI) and their fusion proteins G6PDH-DI and DI-G6PDH were cloned from Geobacillus stearothermophilus, heterologouely expressed in E. coli and purified through its His-tag. The individual proteins G6PDH and DI have good thermostability and reactivity. However, the presence of DI in fusion proteins drastically decreased G6DPH activity. However, a mixture of G6PDH and a fusion protein G6PDH-DI not only restored G6PDH activity through the formation of heteromultimeric network but also facilitated substrate channeling between DI and G6PDH, especially at low enzyme concentrations. My researches would provide important building blocks for the on-going projects: high-yield hydrogen production through cell-free enzymatic pathways and electrical energy production through enzymatic fuel cells. Advisors/Committee Members: Zhang, Y. H. Percival (committeechair), Zhang, Chenming Mike (committee member), Capelluto, Daniel G. S. (committee member).

Subjects/Keywords: substrate channeling; synthetic pathway biotranformation (SyPaB); diaphorase; glucose-6-phosphate dehydrogenase; RpiB; ribose-5-phosphate isomerase; thermostable enzymes; biofuel

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APA (6^th Edition):

Sun, F. (2012). Development of Building Blocks - Thermostable Enzymes for Synthetic Pathway Biotransformation (SyPaB). (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/77009

Chicago Manual of Style (16^th Edition):

Sun, Fangfang. “Development of Building Blocks - Thermostable Enzymes for Synthetic Pathway Biotransformation (SyPaB).” 2012. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/77009.

MLA Handbook (7^th Edition):

Sun, Fangfang. “Development of Building Blocks - Thermostable Enzymes for Synthetic Pathway Biotransformation (SyPaB).” 2012. Web. 18 Jan 2021.

Vancouver:

Sun F. Development of Building Blocks - Thermostable Enzymes for Synthetic Pathway Biotransformation (SyPaB). [Internet] [Masters thesis]. Virginia Tech; 2012. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/77009.

Council of Science Editors:

Sun F. Development of Building Blocks - Thermostable Enzymes for Synthetic Pathway Biotransformation (SyPaB). [Masters Thesis]. Virginia Tech; 2012. Available from: http://hdl.handle.net/10919/77009

Virginia Tech

6. Hu, Jianzhong. Development of subunit vaccines against porcine reproductive and respiratory syndrome virus (PRRSV).

Degree: PhD, Biological Systems Engineering, 2012, Virginia Tech

URL: http://hdl.handle.net/10919/39129

► Since emerging in Europe and the US, PRRS has spread globally and become the most significant infectious disease currently devastating the swine industry. In the… (more)

▼ Since emerging in Europe and the US, PRRS has spread globally and become the most significant infectious disease currently devastating the swine industry. In the US alone, the economic losses caused by this disease amount to more than 560 million US dollars every year. Modified-live PRRSV vaccines (MLV) are the most effective option currently available for the control of the disease. MLVs can confer solid protection against homologous re-infection and have significant effects in reducing viral shedding. But the vaccine efficacy varies upon heterologous challenge. None of the current vaccines are able to completely prevent respiratory infection, transplacental transmission, as well as pig-to-pig transmission of the virus. More importantly, the intrinsic risk of MLV vaccine to revert to virulent virus under farm conditions poses a great safety concern. The unsatisfactory efficacy and safety of current PRRSV vaccines drives the continuous efforts of developing a new generation of vaccines. The strategy we focus on for novel PRRSV vaccine development is subunit vaccine. The reasons for choosing this strategy are: 1) subunit vaccines only contain the immunogenic fragments of a pathogen. Administration of such pathogen fragments eliminates the risk of pathogens reverting back to their virulent form as in the case of modified live vaccines. 2) Subunit vaccines have advantages in terms of vaccine production since a well-defined pathogen fragment can more easily be produced consistently. To achieve of our goal of developing safe and efficacious subunit vaccines against PRRSV, three projects were completed. First, a scalable process for purification of PRRSV particles from cell culture was developed. This process produced purified viral particles for ELISA and cell-based assays used in vaccine development. Second, a plant-made oral subunit vaccine against PRRSV was developed. Administration of the plant-made vaccine, the vaccinated animals produced virus-specific serum and intestine mucosal antibodies with neutralization activity, as well as cellular immune responses with a preference of virus-specific IFN-Î³ production. Since neutralization antibodies and virus-specific IFN-Î³ response are the crucial factors contributing to protection against PRRSV infection, the plant-made oral subunit vaccine strategy is an attractive strategy for developing a new generation of the vaccine to control PRRS disease. Third, a chimeric protein consisting of the ectodomains of viral M and GP5 proteins was expressed and purified. The protein product showed a single band on a silver-stained gel and contained an endotoxin level of less than 10 EU/mg protein. In addition, the purified protein showed expected bioactivities. It was antigenic, could bind to a cellular receptor for the virus (heparan sulfate), and could block virus infection of susceptible cells. Therefore, the chimeric protein is a promising subunit vaccine candidate against PRRSV. Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Meng, Xiang-Jin (committee member), Barone, Justin R. (committee member), LeRoith, Tanya (committee member).

Subjects/Keywords: protein purification; vaccine; PRRSV; PRRS; M protein; porcine reproductive and respiratory syndrome viru

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APA (6^th Edition):

Hu, J. (2012). Development of subunit vaccines against porcine reproductive and respiratory syndrome virus (PRRSV). (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/39129

Chicago Manual of Style (16^th Edition):

Hu, Jianzhong. “Development of subunit vaccines against porcine reproductive and respiratory syndrome virus (PRRSV).” 2012. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/39129.

MLA Handbook (7^th Edition):

Hu, Jianzhong. “Development of subunit vaccines against porcine reproductive and respiratory syndrome virus (PRRSV).” 2012. Web. 18 Jan 2021.

Vancouver:

Hu J. Development of subunit vaccines against porcine reproductive and respiratory syndrome virus (PRRSV). [Internet] [Doctoral dissertation]. Virginia Tech; 2012. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/39129.

Council of Science Editors:

Hu J. Development of subunit vaccines against porcine reproductive and respiratory syndrome virus (PRRSV). [Doctoral Dissertation]. Virginia Tech; 2012. Available from: http://hdl.handle.net/10919/39129

Virginia Tech

7. Badieyan, Somayesadat. Molecular Design and Mechanistic Characterization of Glycoside Hydrolases using Computational and Experimental Techniques.

Degree: PhD, Biological Systems Engineering, 2012, Virginia Tech

URL: http://hdl.handle.net/10919/77989

► Cellulase activity is due to the activity of multiple enzymes, including endoglucanases, cellobiohydrolases and glucosidases that work synergistically to solubilize crystalline cellulose efficiently. The dependence… (more)

▼ Cellulase activity is due to the activity of multiple enzymes, including endoglucanases, cellobiohydrolases and glucosidases that work synergistically to solubilize crystalline cellulose efficiently. The dependence of hydrolysis reaction rate on temperature predicts that large increases in performance and decreased enzyme cost would be achieved if the enzymatic degradation could be operated at elevated temperatures. However there is always a tradeoff between the activity and stability of enzymes. So obtaining cellulases with high thermostability and simultaneously enhanced activity is a great challenge in the field of bioethanol production. In the studies presented in this dissertation, different computational techniques, such as Molecular Dynamics (MD), Molecular Docking, Quantum Mechanics (QM) and hybrid Quantum Mechanics and Molecular Mechanics (QM/MM), along with several site-directed mutagenesis and in vitro assays have been applied to the study and design of the activity and stability of cellulases. Using molecular dynamics to investigate the thermal unfolding of endoglucanases of family 5 of glycoside hydrolases (GH5), a good correlation between the optimum activity temperatures of cellulases and their structural fluctuations was revealed. These data led us to hypothesize that cellulase stability could be enhanced by redesign of enzyme dynamics through altering the amino acid composition in the highly flexible regions of an endoglucanase that would increase its local or global rigidity. Cellulase C, a GH5 member, was stabilized thermally and chemically by cross linking its highly flexible subdomain. Family 1 of glycoside hydrolases were investigated by QM and hybrid QM/MM methods to analyze the role of non-catalytic polar residues at the active site of GH1 glucosidases that make hydrogen bonds to the glucose moiety at subsite -1. A tyrosine residue in simultaneous interaction with O5 of the glucose ring and the carboxylate group of the nucleophilic glutamate was found to play a significant role in the energy profile along the hydrolysis reaction coordinates. It was shown to reduce the energy barrier of the deglycosylation step by ~12 Kcal/mol. Exclusion of this tyrosine from QM calculation substantially influenced the preactivated structure of the glucose moiety in the enzyme-substrate complex and affected the structural distortion and charge distribution in transition states. Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Sobrado, Pablo (committee member), Bevan, David R. (committee member), Barone, Justin R. (committee member).

Subjects/Keywords: Glycoside Hydrolases; Protein design; Thermostability; Reaction mechanism; Molecular Dynamics; Quantum Mechanism

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APA (6^th Edition):

Badieyan, S. (2012). Molecular Design and Mechanistic Characterization of Glycoside Hydrolases using Computational and Experimental Techniques. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/77989

Chicago Manual of Style (16^th Edition):

Badieyan, Somayesadat. “Molecular Design and Mechanistic Characterization of Glycoside Hydrolases using Computational and Experimental Techniques.” 2012. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/77989.

MLA Handbook (7^th Edition):

Badieyan, Somayesadat. “Molecular Design and Mechanistic Characterization of Glycoside Hydrolases using Computational and Experimental Techniques.” 2012. Web. 18 Jan 2021.

Vancouver:

Badieyan S. Molecular Design and Mechanistic Characterization of Glycoside Hydrolases using Computational and Experimental Techniques. [Internet] [Doctoral dissertation]. Virginia Tech; 2012. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/77989.

Council of Science Editors:

Badieyan S. Molecular Design and Mechanistic Characterization of Glycoside Hydrolases using Computational and Experimental Techniques. [Doctoral Dissertation]. Virginia Tech; 2012. Available from: http://hdl.handle.net/10919/77989

Virginia Tech

8. Zhou, Rui. FITSelect: An Invention to Select Microbial Strains Maximizing Product Formation from a Single Culture Without High-Throughput Screening.

Degree: MS, Biological Systems Engineering, 2011, Virginia Tech

URL: http://hdl.handle.net/10919/76843

► In metabolic engineering of prokaryotes, combinatorial approaches have developed recently that induce random genetic perturbations to achieve a desired cell phenotype. A screening strategy follows… (more)

▼ In metabolic engineering of prokaryotes, combinatorial approaches have developed recently that induce random genetic perturbations to achieve a desired cell phenotype. A screening strategy follows the randomized genetic manipulations to select strain(s) with the more optimal phenotype of interest. This screening strategy is often divided into two categories: (i) a growth competition assay and (ii) selection by high-throughput screening. The growth competition assay involves culturing strains together. The strain with the highest growth rate will ultimately dominate the culture. This strategy is ideal for selecting strain with cellular fitness (e.g., solvent tolerance), but it does not work for selecting a strain that can over-produce a product (e.g., an amino acid). For the case of selecting highly productive phenotypes, high-throughput screening is used. This method analyzes strains individually and is costly and time-consuming. In this research, a synthetic genetic circuit was developed to select highly productive phenotypes using a growth competition assay rather than high-throughput screening. This novel system is called Feed-back Inhibition of Transcription for Growth Selection (FITSelect), and it uses a natural feedback inhibition mechanism in the L-arginine production pathway to select strains (transformed with a random genomic library) that can over-produce L-arginine in E. coli DH10B. With FITSelect, the cell can thrive in the growth competition assay when L-arginine is over-produced (i.e., growth is tied to L-arginine production). Cell death or reduced growth results if L-arginine is not over-produced by the cell. This system was created by including an L-arginine concentration responsive argF promoter to control a ccdB cell death gene in the FITSelect system. The effects of ccdB were modulated by the antidote ccdA gene under control of an L-tryptophan responsive trp promoter. Several insights and construction strategies were required to build a system that ties the growth rate of the cell to L-arginine concentrations. Advisors/Committee Members: Senger, Ryan S. (committeechair), Collakova, Eva (committee member), Zhang, Chenming Mike (committee member), Barone, Justin R. (committee member).

Subjects/Keywords: synthetic biology; growth competition assay; combinatorial methods; metabolic engineering

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APA (6^th Edition):

Zhou, R. (2011). FITSelect: An Invention to Select Microbial Strains Maximizing Product Formation from a Single Culture Without High-Throughput Screening. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/76843

Chicago Manual of Style (16^th Edition):

Zhou, Rui. “FITSelect: An Invention to Select Microbial Strains Maximizing Product Formation from a Single Culture Without High-Throughput Screening.” 2011. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/76843.

MLA Handbook (7^th Edition):

Zhou, Rui. “FITSelect: An Invention to Select Microbial Strains Maximizing Product Formation from a Single Culture Without High-Throughput Screening.” 2011. Web. 18 Jan 2021.

Vancouver:

Zhou R. FITSelect: An Invention to Select Microbial Strains Maximizing Product Formation from a Single Culture Without High-Throughput Screening. [Internet] [Masters thesis]. Virginia Tech; 2011. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/76843.

Council of Science Editors:

Zhou R. FITSelect: An Invention to Select Microbial Strains Maximizing Product Formation from a Single Culture Without High-Throughput Screening. [Masters Thesis]. Virginia Tech; 2011. Available from: http://hdl.handle.net/10919/76843

Virginia Tech

9. Ye, Xinhao. Enzymatic Production of Cellulosic Hydrogen by Cell-free Synthetic Pathway Biotransformation(SyPaB).

Degree: PhD, Biological Systems Engineering, 2011, Virginia Tech

URL: http://hdl.handle.net/10919/77141

► The goals of this research were 1) to produce hydrogen in high yields from cellulosic materials and water by synthetic pathway biotranformation (SyPaB), and 2)… (more)

▼ The goals of this research were 1) to produce hydrogen in high yields from cellulosic materials and water by synthetic pathway biotranformation (SyPaB), and 2) to increase the hydrogen production rate to a level comparable to microbe-based methods (~ 5 mmol H2/L/h). Cell-free SyPaB is a new biocatalysis technology that integrates a number of enzymatic reactions from four different metabolic pathways, e.g. glucan phosphorylation, pentose phosphate pathway, gluconeogenesis, and hydrogenase-catalyzed hydrogen production, so as to release 12 mol hydrogen per mol glucose equivalent. To ensure the artificial enzymatic pathway would work for hydrogen production, thermodynamic analysis was firstly conducted, suggesting that the artificial enzymatic pathway would spontaneously release hydrogen from cellulosic materials. A kinetic model was constructed to assess the rate-limited step(s) through metabolic control analysis. Three phosphorylases, i.e. α-glucan phosphorylase, cellobiose phosphorylase, and cellodextrin phosphorylase, were cloned from a thermophile Clostridium thermocellum, and heterologously expressed in Escherichia coli, purified and characterized in detail. Finally, up to 93% of hydrogen was produced from cellulosic materials (11.2 mol H2/mol glucose equivalent). A nearly 20-fold enhancement in hydrogen production rates has been achieved by increasing the rate-limiting hydrogenase concentration, increasing the substrate loading, and elevating the reaction temperature slightly from 30 to 32°C. The hydrogen production rates were higher than those of photobiological systems and comparable to the rates reported in dark fermentations. Now the hydrogen production is limited by the low stabilities and low activities of various phosphorylases. Therefore, non-biologically based methods have been applied to prolong the stability of α-glucan phosphorylases. The catalytic potential of cellodextrin phosphorylase has been improved to degrade insoluble cellulose by fusion of a carbohydrate-binding module (CBM) family 9 from Thermotoga maritima Xyn10A. The inactivation halftime of C. thermocellum cellobiose phosphorylase has been enhanced by three-fold at 70°C via a combination of rational design and directed evolution. The phosphorylases with improved properties would work as building blocks for SyPaB and enabled large-scale enzymatic production of cellulosic hydrogen. Advisors/Committee Members: Zhang, Yi Heng Percival (committeechair), Barone, Justin R. (committee member), Larson, Timothy J. (committee member), Zhang, Chenming Mike (committeecochair).

Subjects/Keywords: synthetic pathway biotranformation (SyPaB); rational design; protein engineering; phosphorylase; biofuel; directed evolution; hydrogen

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APA (6^th Edition):

Ye, X. (2011). Enzymatic Production of Cellulosic Hydrogen by Cell-free Synthetic Pathway Biotransformation(SyPaB). (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/77141

Chicago Manual of Style (16^th Edition):

Ye, Xinhao. “Enzymatic Production of Cellulosic Hydrogen by Cell-free Synthetic Pathway Biotransformation(SyPaB).” 2011. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/77141.

MLA Handbook (7^th Edition):

Ye, Xinhao. “Enzymatic Production of Cellulosic Hydrogen by Cell-free Synthetic Pathway Biotransformation(SyPaB).” 2011. Web. 18 Jan 2021.

Vancouver:

Ye X. Enzymatic Production of Cellulosic Hydrogen by Cell-free Synthetic Pathway Biotransformation(SyPaB). [Internet] [Doctoral dissertation]. Virginia Tech; 2011. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/77141.

Council of Science Editors:

Ye X. Enzymatic Production of Cellulosic Hydrogen by Cell-free Synthetic Pathway Biotransformation(SyPaB). [Doctoral Dissertation]. Virginia Tech; 2011. Available from: http://hdl.handle.net/10919/77141

Virginia Tech

10. Abdellaoui, Hamza. Investigation of Poultry Litter Bochar as a Potential Electrode for Direct Carbon Fuel Cells.

Degree: MS, Biological Systems Engineering, 2013, Virginia Tech

URL: http://hdl.handle.net/10919/49617

► Direct carbon fuel cell (DCFC) is a high temperature fuel cell (around 700 "C) that produces electrical energy from the direct conversion of the chemical… (more)

▼ Direct carbon fuel cell (DCFC) is a high temperature fuel cell (around 700 "C) that produces electrical energy from the direct conversion of the chemical energy of carbon. DCFC has a higher achievable efficiency of 80% compared to other fuel cells and the corresponding CO2 emission is very low compared to conventional coal-burning power plants. Moreover, a DCFC can use diversified fuel resources even waste material, which is advantageous compared to other types of fuel cells which are limited to specific fuels. DCFCs are still under development due to a number of fundamental and technological challenges such as the efficiency of carbon fuels and the effect of impurities on the performance and lifetime of the DCFC. These are key factors for the development and commercialization of these devices. In this study, three biochars obtained from the pyrolysis of poultry litters (PL) collected from Tunisian and US farmers, were characterized to see whether they can be potential anode fuels for DCFC or not. PL biochars have low fixed carbon contents (19-35 wt%) and high ash contents (32.5-63 wt%). These ashes contain around 40 wt% catalytic oxides for carbon oxidation reaction, however, these oxides have very low electrical conductivities, which resulted in the very low (negligible) electrical conductivity of the PL biochars (7.7x10-9-70.56x10-9 S/cm) at room temperature. Moreover, the high ash contents resulted in low surface areas (3.34-4.2 m"/g). These findings disqualified PL biochar from being a potential anode fuel for DCFCs. Chemical demineralization in the sequence HF/HCl followed by carbonization at 950" C of the PL biochars will result in higher fixed carbon content, higher surface area, and higher electrical conductivities. Moreover, the treated PL biochars would contain a potential catalyst (Calcium in the form of CaF2) for carbon oxidation. All these criteria would qualify the treated PL biochars to be potential fuels for DCFC. Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Agblevor, Foster Aryi (committeechair), Senger, Ryan S. (committee member), Halouani, Kamel (committee member).

Subjects/Keywords: Poultry litter biochar; Direct Carbon Fuel Cell; demineralization; carbonization; electrical conductivity

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APA (6^th Edition):

Abdellaoui, H. (2013). Investigation of Poultry Litter Bochar as a Potential Electrode for Direct Carbon Fuel Cells. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/49617

Chicago Manual of Style (16^th Edition):

Abdellaoui, Hamza. “Investigation of Poultry Litter Bochar as a Potential Electrode for Direct Carbon Fuel Cells.” 2013. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/49617.

MLA Handbook (7^th Edition):

Abdellaoui, Hamza. “Investigation of Poultry Litter Bochar as a Potential Electrode for Direct Carbon Fuel Cells.” 2013. Web. 18 Jan 2021.

Vancouver:

Abdellaoui H. Investigation of Poultry Litter Bochar as a Potential Electrode for Direct Carbon Fuel Cells. [Internet] [Masters thesis]. Virginia Tech; 2013. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/49617.

Council of Science Editors:

Abdellaoui H. Investigation of Poultry Litter Bochar as a Potential Electrode for Direct Carbon Fuel Cells. [Masters Thesis]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/49617

Virginia Tech

11. Khili, Mouna. Characterization of Value Added Proteins and Lipids form Microalgae.

Degree: MS, Biological Systems Engineering, 2013, Virginia Tech

URL: http://hdl.handle.net/10919/49673

► Microalgae have been so far identified as the major producers of organic matter through their photosynthetic activities. In the present work, Nannochloris sp. and Amphora… (more)

Subjects/Keywords: microalgae; enzyme assays; lipids analysis; transesterification.

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APA (6^th Edition):

Khili, M. (2013). Characterization of Value Added Proteins and Lipids form Microalgae. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/49673

Chicago Manual of Style (16^th Edition):

Khili, Mouna. “Characterization of Value Added Proteins and Lipids form Microalgae.” 2013. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/49673.

MLA Handbook (7^th Edition):

Khili, Mouna. “Characterization of Value Added Proteins and Lipids form Microalgae.” 2013. Web. 18 Jan 2021.

Vancouver:

Khili M. Characterization of Value Added Proteins and Lipids form Microalgae. [Internet] [Masters thesis]. Virginia Tech; 2013. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/49673.

Council of Science Editors:

Khili M. Characterization of Value Added Proteins and Lipids form Microalgae. [Masters Thesis]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/49673

Virginia Tech

12. Mante, Nii Ofei Daku. Fractional Catalytic Pyrolysis Technology for the Production of Upgraded Bio-oil using FCC Catalyst.

Degree: PhD, Biological Systems Engineering, 2011, Virginia Tech

URL: http://hdl.handle.net/10919/40436

► Catalytic pyrolysis technology is one of the thermochemical platforms used to produce high quality bio-oil and chemicals from biomass feedstocks. In the catalytic pyrolysis process,… (more)

▼ Catalytic pyrolysis technology is one of the thermochemical platforms used to produce high quality bio-oil and chemicals from biomass feedstocks. In the catalytic pyrolysis process, the biomass is rapidly heated under inert atmosphere in the presence of an acid catalyst or zeolite to promote deoxygenation and cracking of the primary vapors into hydrocarbons and small oxygenates. This dissertation examines the utilization of conventional fluid catalytic cracking (FCC) catalyst in the fractional catalytic pyrolysis of hybrid poplar wood. The influence of Y-zeolite content, steam treatment, addition of ZSM-5 additive, process conditions (temperature, weight hourly space velocity (WHSV) and vapor residence time) and recycling of the non-condensable gases (NCG) on the product distribution and the quality of the bio-oil were investigated. The first part of the study demonstrates the influence of catalytic property of FCC catalyst on the product distribution and quality of the bio-oil. It was found that FCC catalyst with higher Y-zeolite content produces higher coke yield and lower organic liquid fraction (OLF). Conversely, FCC catalyst with lower Y-zeolite content results in lower coke yield and higher OLF. The results showed that higher Y-zeolite content extensively cracks dehydrated products from cellulose decomposition and demethoxylates phenolic compounds from lignin degradation. The Y-zeolite promoted both deoxygenation and coke forming reactions due to its high catalytic activity and large pore size. Higher Y-zeolite content increased the quality of the bio-oil with respect to higher heating value (HHV), pH, density, and viscosity. The steam treatment at 732 °C and 788 °C decreased the total BET surface area of the FCC catalyst. The findings suggest that steam treatment reduces the coking tendency of the FCC catalyst and enhances the yield of the OLF. Analysis of the bio-oils showed that the steamed FCC catalyst produces bio-oil with lower viscosity and density. Gas chromatography and 13C-NMR spectrometry suggest that steam treatment affect the catalyst selectivity in the formation of CO, CO2, H2, CH4, C2-C5 hydrocarbons and aromatic hydrocarbons. The addition of ZSM-5 additive to the FCC catalyst was found to alter the characteristic/functionality of the catalytic medium. The product slate showed decrease in coke yield and increase in OLF with increase in ZSM-5 additive. The FCC/ZSM-5 additive hybrid catalysts produced bio-oils with relatively lower viscosity and higher pH value. The formation of CO2, CH4, and H2 decreased whilst C5 and aromatic hydrocarbons increased with increase in ZSM-5 additive level. The second part of the work assesses the effect of operating conditions on the catalytic pyrolysis process. The response surface methodology study showed reaction temperature to be the most influential statistically significant independent variable on char/coke yield, concentration of non-condensable gases, carbon content, oxygen content, pH and viscosity of the bio-oils. The WHSV was the most important… Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Jayaram, Sankar (committee member), Frazier, Charles E. (committee member), McClung, Ronald G. (committee member), Agblevor, Foster Aryi (committeecochair).

Subjects/Keywords: fractional catalytic pyrolysis; FCC catalyst; bio-oil; biomass; response surface methodology; recycling of non-condensable gases; Y-zeolite; ZSM-5

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APA (6^th Edition):

Mante, N. O. D. (2011). Fractional Catalytic Pyrolysis Technology for the Production of Upgraded Bio-oil using FCC Catalyst. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/40436

Chicago Manual of Style (16^th Edition):

Mante, Nii Ofei Daku. “Fractional Catalytic Pyrolysis Technology for the Production of Upgraded Bio-oil using FCC Catalyst.” 2011. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/40436.

MLA Handbook (7^th Edition):

Mante, Nii Ofei Daku. “Fractional Catalytic Pyrolysis Technology for the Production of Upgraded Bio-oil using FCC Catalyst.” 2011. Web. 18 Jan 2021.

Vancouver:

Mante NOD. Fractional Catalytic Pyrolysis Technology for the Production of Upgraded Bio-oil using FCC Catalyst. [Internet] [Doctoral dissertation]. Virginia Tech; 2011. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/40436.

Council of Science Editors:

Mante NOD. Fractional Catalytic Pyrolysis Technology for the Production of Upgraded Bio-oil using FCC Catalyst. [Doctoral Dissertation]. Virginia Tech; 2011. Available from: http://hdl.handle.net/10919/40436

Virginia Tech

13. McAnulty, Michael Justin. Total proton flux and balancing in genome-scale models: The case for the updated model of Clostridium acetobutylicum ATCC 824.

Degree: MS, Biological Systems Engineering, 2011, Virginia Tech

URL: http://hdl.handle.net/10919/44199

► Genome-scale modeling and new strategies for constraining these models were applied in this research to find new insights into cellular metabolism and identify potential metabolic… (more)

▼ Genome-scale modeling and new strategies for constraining these models were applied in this research to find new insights into cellular metabolism and identify potential metabolic engineering strategies. A newly updated genome-scale model for Clostridium acetobutylicum, iMM864, was constructed, largely based on the previously published iRS552 model. The new model was built using a newly developed genome-scale model database, and updates were derived from new insights into clostridial metabolism. Novel methods of proton-balancing and setting flux (defined as reaction rate (mmol/g biomass/hr)) ratio constraints were applied to create simulations made with the iMM864 model approximate observed experimental results. It was determined that the following constraints must be applied to properly model C. acetobutylicum metabolism: (1) proton-balancing, (2) constraining the specific proton flux (SPF), and (3) installing proper flux ratio constraints. Simulations indicate that the metabolic shift into solventogenesis is not due to optimizing growth at different pH conditions. However, they provide evidence that C. acetobutylicum has developed strictly genetically regulated solventogenic metabolic pathways for the purpose of increasing its surrounding pH to decrease the toxic effects of high proton concentrations. Applying a ratio constraint for the P/O ratio (a measure of aerobic respiratory efficiency) to the iAF1260 genome-scale model of E. coli K12 MG1655 was explored. Relationships were found between: (1) the P/O ratio, (2) the SPF, (3) the growth rate, and (4) the production of acetate. As was expected, higher acetate production correlates with lower P/O ratios, while higher growth correlates with higher P/O ratios. For the first time, a genome-scale model was able to quantify this relationship and targeting both the P/O ratio and the SFP is required to produce an E. coli K12 strain with either (i) maximized growth rate (and minimized acetate production) or (ii) maximized acetate production (at the expense of cell growth). A gene knockout mutant, Î ndh, was created with E. coli BL-21 to study the effects of forcibly higher P/O ratios on growth. The results suggest that a metabolic bottleneck lies with the NADH-1 complex, the NADH dehydrogenase that contributes to the generation of a proton motive force. Advisors/Committee Members: Senger, Ryan S. (committeechair), Collakova, Eva (committee member), Zhang, Chenming Mike (committee member), Ogejo, Jactone Arogo (committee member).

Subjects/Keywords: genome-scale modeling; proton balancing; Clostridium acetobutylicum; biofuels; acidogenesis; solventogenesis; P/O ratio

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APA (6^th Edition):

McAnulty, M. J. (2011). Total proton flux and balancing in genome-scale models: The case for the updated model of Clostridium acetobutylicum ATCC 824. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/44199

Chicago Manual of Style (16^th Edition):

McAnulty, Michael Justin. “Total proton flux and balancing in genome-scale models: The case for the updated model of Clostridium acetobutylicum ATCC 824.” 2011. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/44199.

MLA Handbook (7^th Edition):

McAnulty, Michael Justin. “Total proton flux and balancing in genome-scale models: The case for the updated model of Clostridium acetobutylicum ATCC 824.” 2011. Web. 18 Jan 2021.

Vancouver:

McAnulty MJ. Total proton flux and balancing in genome-scale models: The case for the updated model of Clostridium acetobutylicum ATCC 824. [Internet] [Masters thesis]. Virginia Tech; 2011. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/44199.

Council of Science Editors:

McAnulty MJ. Total proton flux and balancing in genome-scale models: The case for the updated model of Clostridium acetobutylicum ATCC 824. [Masters Thesis]. Virginia Tech; 2011. Available from: http://hdl.handle.net/10919/44199

Virginia Tech

14. Hu, Yun. Development of nanoparticle based nicotine vaccines for smoking cessation.

Degree: PhD, Biological Systems Engineering, 2015, Virginia Tech

URL: http://hdl.handle.net/10919/73574

► Cigarette smoking is prevalent worldwide and has consistently been the top preventable cause of many serious diseases., which result in huge mortality, morbidity, and economic… (more)

▼ Cigarette smoking is prevalent worldwide and has consistently been the top preventable cause of many serious diseases., which result in huge mortality, morbidity, and economic loss, in recent decades. In recent years, nicotine vaccines that can induce production of nicotine specific antibodies in human have emerged as a promising medicine to treat tobacco addiction. In the past decade, there have been numerous nicotine vaccine candidates evaluated in human clinical trials, including NicVaxNicVAX®, TA-NICTA-NIC®, Nic002NIC002®, NiccineNiccine®, and SEL-068SEL-068®. . However, traditional nicotine vaccine designs haves many disadvantages, including low immunogenicity, low specificity, difficulty in integration of molecular adjuvants, and short immune response persistence. To overcome the above limitations, in this study, various nanoparticle-based vaccine delivery systemsvaccine componentss have been developed and evaluated as potential delivery vehicles for vaccines against nicotine addiction. Firstly, a nicotine vaccine was synthesized by conjugating bovine serum albumin (BSA)-nicotine complex to the surface of nano-sized cationic liposome. Significantly higher anti-nicotine antibody titer was achieved in mice by liposome delivered nicotine vaccine compared with nicotine-BSA vaccine. Secondly, a novel nanoparticle (NP)-based delivery platform was constructed by incorporating a negatively charged nanohorn into cationic liposome to improve the stability of liposome and reduce nanoparticle flocculation. Subsequently, nicotine vaccine was constructed by conjugating nicotine-BSA complex to the surface of the nanohorn supported liposome (NsL). Marked improvement in stability in vitro and significant increase in titer of anti-nicotine antibodies were detected in nanohorn supported liposome ( NsL) delivered vaccine than liposome delivered vaccine. In addition, NsL nicotine vaccine exhibited good safety in mice after multiple injections. Thirdly, lipid- poly(lactic-co-glycolic acid) (PLGA) hybrid NPs were constructed as vaccine delivery system. due to the fact that nanohorn is not currently approved for clinical use, we substituted the nanohorn with poly(lactic-co-glycolic acid) (PLGA) nanoparticles and constructed PLGA-lipid hybrid nanoparticles. Preliminary results showed that PLGA-lipid hybrid NPs nanoparticles exhibited improved stability, better controlled release of antigens, as well as enhanced uptake by dendritic cell (DC). A lipid-PLGA hybrid NPnanoparticle was also developed that was structurally responsive to low pH challenge. The lipid shell of the hybrid nanoparticle was rapidly disintegrated under a low pH challenge, which resembles the acidic environment of endosomes in DCsdendritic cells. The hybrid NPs exhibited minimal antigen release in human serum at physiological pH, but a faster release of antigen from this NP compared to non-pH sensitive NPs was observed in DC. In the final study, hybrid NPnanoparticles with various cholesterol concentrations were constructed. Slower and more controlled release… Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Ehrich, Marion F. (committee member), Meng, Xiang-Jin (committee member), Senger, Ryan S. (committee member).

Subjects/Keywords: nicotine vaccine; nanoparticle; smoking cessation; liposome; humoral response

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hu, Y. (2015). Development of nanoparticle based nicotine vaccines for smoking cessation. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/73574

Chicago Manual of Style (16^th Edition):

Hu, Yun. “Development of nanoparticle based nicotine vaccines for smoking cessation.” 2015. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/73574.

MLA Handbook (7^th Edition):

Hu, Yun. “Development of nanoparticle based nicotine vaccines for smoking cessation.” 2015. Web. 18 Jan 2021.

Vancouver:

Hu Y. Development of nanoparticle based nicotine vaccines for smoking cessation. [Internet] [Doctoral dissertation]. Virginia Tech; 2015. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/73574.

Council of Science Editors:

Hu Y. Development of nanoparticle based nicotine vaccines for smoking cessation. [Doctoral Dissertation]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/73574

Virginia Tech

15. Huang, Wei. Assembly, characterization and evaluation of a 3rd generation nanoparticle based drug carrier for metastatic breast cancer treatment.

Degree: PhD, Biological Systems Engineering, 2013, Virginia Tech

URL: http://hdl.handle.net/10919/50932

► Cancer is one of the leading causes of death in the world. For women in the U.S. and the European countries, breast cancer is the… (more)

▼ Cancer is one of the leading causes of death in the world. For women in the U.S. and the European countries, breast cancer is the most common type and it continuously threatens the lives of the patients and causes huge economic losses. Chemotherapy and endocrine therapy are the common treatments for recurrence prevention and metastatic cancer symptom palliation. However, the uses of these therapies are meanwhile largely limited because their toxic side effects and non-specificity usually lead to low quality lives of the patients. Low aqueous solubility, multi-drug resistance, degradation of drug, limited intra-tumor diffusion and etc. are other limitations of conventional chemotherapies and endocrine therapies. Nanoparticle based drug carriers were extensively studied for therapeutic drug delivery. Many carriers could be loaded with high dose of hydrophobic and hydrophilic drugs, protect the drug from the surrounding in vivo environment during the transportation, specifically target and enter the tumor cells and slowly release the drug thereafter. Advanced nanoparticle drug carriers are studied driven by the need of a more efficient drug delivery. The 3rd generation of nanoparticle based drug carriers are recently developed. They usually consist of more than one type of nanoparticles. Different part of the particle has more specialized functions. Therefore, by carefully selecting from the conventional nanoparticle carriers, a 3rd generation particle could have the properties such as high loading capacity of multiple drugs, prolonged half-life in circulation, higher tendency of accumulating at the tumor site, improved specificity to the tumor cells, higher cell uptake rate and accurately triggered controlled release, and combination of the above-mentioned properties. In our study, a paclitaxel loaded nanoparticle supported immunoliposome was assembled for metastatic breast cancer drug delivery. Functionalized single walled carbon nanohorn or poly(lactic-co-glycolic acid) was encapsulated in the polyethylene glycol (PEG) coated liposome for high drug loading and controlled release. Anti-Her2 antibody or Herceptin® was grafted onto the surface of the liposome for a higher affinity to the Her2 overexpressing breast cancer cells. Firstly, the conjugation of protein to the surface of liposome and PEGylated liposomes were investigated. Proteins with or without membrane binding domain were conjugated to liposome and PEGylated liposomes through covalent and non-covalent binding for comparison. A modified enzyme-linked immune sorbent assay was developed for surface grafted protein quantification. Secondly, the encapsulation of solid nanoparticle into PEGylated immunoliposome was investigated. Results showed a new structure of solid nanoparticle in PEGylated immunoliposome at a 1:1 ratio was formed during the repeated freeze-thawing process. Supported immunoliposomes with high homogeneity in size and structure were purified by sucrose density gradient centrifugation. Thirdly, the drug loading,… Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Lazar, Maria Iuliana (committee member), Senger, Ryan S. (committee member), Dorn, Harry C. (committee member), Meng, Xiang-Jin (committee member).

Subjects/Keywords: metastatic breast cancer; nanohorn; immunoliposome; nanoparticle based drug carrier; double controlled release

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Huang, W. (2013). Assembly, characterization and evaluation of a 3rd generation nanoparticle based drug carrier for metastatic breast cancer treatment. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/50932

Chicago Manual of Style (16^th Edition):

Huang, Wei. “Assembly, characterization and evaluation of a 3rd generation nanoparticle based drug carrier for metastatic breast cancer treatment.” 2013. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/50932.

MLA Handbook (7^th Edition):

Huang, Wei. “Assembly, characterization and evaluation of a 3rd generation nanoparticle based drug carrier for metastatic breast cancer treatment.” 2013. Web. 18 Jan 2021.

Vancouver:

Huang W. Assembly, characterization and evaluation of a 3rd generation nanoparticle based drug carrier for metastatic breast cancer treatment. [Internet] [Doctoral dissertation]. Virginia Tech; 2013. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/50932.

Council of Science Editors:

Huang W. Assembly, characterization and evaluation of a 3rd generation nanoparticle based drug carrier for metastatic breast cancer treatment. [Doctoral Dissertation]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/50932

Virginia Tech

16. Teye, Frederick David. Continuous flash extraction of alcohols from fermentation broth.

Degree: MS, Biological Systems Engineering, 2009, Virginia Tech

URL: http://hdl.handle.net/10919/31418

► A new method of in situ extraction of alcohols from fermentation broth was investigated. The extraction method exploited the latent advantages of the non-equilibrium phase… (more)

▼ A new method of in situ extraction of alcohols from fermentation broth was investigated. The extraction method exploited the latent advantages of the non-equilibrium phase interaction of the fluid system in the flash tank to effectively recover the alcohol. Carbon dioxide gas ranging from 4.2L/min to 12.6L/min was used to continuously strip 2 and 12% (v/v) ethanol solution in a fermentor with a recycle. Ethanol and water in the stripped gas was recovered by compressing and then flashing into a flash tank that was maintained at 5 to 70bar and 5 to 55 °C where two immiscible phases comprising CO2-rich phase (top layer) and H2O-rich phase (bottom layer) were formed. The H2O-rich bottom layer was collected as the Bottoms. The CO2-rich phase was continuously throttled producing a condensate (Tops) as a result of the Joule-Thompson cooling effect. The total ethanol recovered from the extraction scheme was 46.0 to 80% for the fermentor containing 2% (v/v) ethanol and 57 to 89% for the fermentor containing 12% (v/v) ethanol. The concentration of ethanol in the Bottoms ranged from 8.0 to 14.9 %(v/v) for the extraction from the 2 %(v/v) ethanol solution and 40.0 to 53.8 %(v/v) for the 12% (v/v) fermentor ethanol extraction. The Bottoms concentration showed a fourfold increase compared to the feed. The ethanol concentration of the Tops were much higher with the highest at approx. 90% (v/v) ethanol, however the yields were extremely low. Compression work required ranged from 6.4 to 20.1 MJ/kg ethanol recovered from the gas stream in the case of 12% (v/v) ethanol in fermentor. The energy requirement for the 2% (v/v) extraction was 84MJ/kg recovered ethanol. The measured Joule-Thompson cooling effect for the extraction scheme was in the range of 10 to 20% the work of compressing the gas. The lowest measured throttle valve temperature was -47 °C at the flash tank conditions of 70bar and 25 °C. Optimization of the extraction scheme showed that increasing the temperature of the flash tank reduced the amount of ethanol recovered. Increasing the pressure of the flash tank increased the total ethanol recovered but beyond 45bar it appeared to reduce the yield. The 12.6L/min carbon dioxide flow rate favored the high pressure(70bar) extraction whiles 4.2L/min appeared to favor the low pressure(40bar) extraction. The studies showed that the extraction method could potentially be used to recover ethanol and other fermentation products. Advisors/Committee Members: Agblevor, Foster Aryi (committeechair), Zhang, Chenming Mike (committee member), Achenie, Luke E. K. (committee member).

Subjects/Keywords: saturation temperature; equilibrium; Flashing; Bottoms; Tops; critical pressure; gas partition; Joule-Thompson coefficient; critical temperature; isothermal flash tank; throttling; saturation pressure

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APA (6^th Edition):

Teye, F. D. (2009). Continuous flash extraction of alcohols from fermentation broth. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/31418

Chicago Manual of Style (16^th Edition):

Teye, Frederick David. “Continuous flash extraction of alcohols from fermentation broth.” 2009. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/31418.

MLA Handbook (7^th Edition):

Teye, Frederick David. “Continuous flash extraction of alcohols from fermentation broth.” 2009. Web. 18 Jan 2021.

Vancouver:

Teye FD. Continuous flash extraction of alcohols from fermentation broth. [Internet] [Masters thesis]. Virginia Tech; 2009. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/31418.

Council of Science Editors:

Teye FD. Continuous flash extraction of alcohols from fermentation broth. [Masters Thesis]. Virginia Tech; 2009. Available from: http://hdl.handle.net/10919/31418

Virginia Tech

17. Hey, Carolyn McKenzie. Antibody Purification from Tobacco by Protein A Affinity Chromatography.

Degree: MS, Biological Systems Engineering, 2010, Virginia Tech

URL: http://hdl.handle.net/10919/42645

► Antibodies represent the largest group of biopharmaceuticals. Due to the nature of their clinical applications, they often need to be produced in large quantities. Plants… (more)

▼ Antibodies represent the largest group of biopharmaceuticals. Due to the nature of their clinical applications, they often need to be produced in large quantities. Plants have distinct advantages of producing large quantities of recombinant proteins, and tobacco is arguably the most promising plant for plant-made-pharmaceuticals (PMP) due to its high biomass yields and robust transformation technology. However, to produce proteins using transgenic tobacco for human applications, purification of the proteins is challenging. On the other hand, Protein A, a bacterial cell wall protein isolated from Staphylococcus aureus that binds to the Fc regions of immunoglobulins, is useful to the isolation and purification of antibodies. An affinity chromatography purification step utilizing Protein A resin introduced early in the purification process can reduce successive unit operations, thereby reducing the overall process cost. However, directly applying tobacco extract to Protein A chromatography columns may be problematic due to the non-specific binding of native tobacco proteins (NTP). In this project, three different Protein A resins, ProSepvA High Capacity, ProSep-vA Ultra, and ProSep Ultra Plus, marketed by Millipore, were studied to provide valuable information for future downstream processes for antibody purification from transgenic tobacco. The efficiency of the post load wash buffer to reduce non-specific binding of NTP to the ProSep A resins were evaluated by altering the ionic strength and pH. Lower salt concentrations of sodium chloride (NaCl) in the post load wash preformed best at reducing the non-specific binding of NTP to the ProSep A resins, while higher salt concentrations were more effective at reducing the amount of NTP contaminants present during elution of the columns. Using a post load wash buffer with an intermediate pH between the binding buffer and the elution buffer was more efficient at eluting our model antibody, human IgG. However, lowering the ionic strength and the pH of the post load wash buffer resulted in a greater presence of IgG prematurely eluting from the ProSep A resins. The non-specific binding of NTP to the resins reduced the dynamic binding capacity (DBC) of the resins after repeated cycles of tobacco extract samples were loaded onto the column. Nevertheless, cleaning the columns with denaturing solutions, such as urea or guanidine hydrochloride, every 8-10 cycles was effective in regenerating the DBC of the resins and prolonging the life cycle of the resins. This is important to evaluating the economic feasibility of directly using Protein A chromatography to recover antibodies from tobacco extract. Of the three Protein A resins studied, ProSep Ultra Plus performed best for antibody purification from tobacco using a PBS wash buffer with a lower ionic strength of 140mM NaCl and an intermediate pH of 5. Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Barone, Justin R. (committee member), Vinatzer, Boris A. (committee member).

Subjects/Keywords: Tobacco; Protein A; Affinity Chromatography; Antibody

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APA (6^th Edition):

Hey, C. M. (2010). Antibody Purification from Tobacco by Protein A Affinity Chromatography. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/42645

Chicago Manual of Style (16^th Edition):

Hey, Carolyn McKenzie. “Antibody Purification from Tobacco by Protein A Affinity Chromatography.” 2010. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/42645.

MLA Handbook (7^th Edition):

Hey, Carolyn McKenzie. “Antibody Purification from Tobacco by Protein A Affinity Chromatography.” 2010. Web. 18 Jan 2021.

Vancouver:

Hey CM. Antibody Purification from Tobacco by Protein A Affinity Chromatography. [Internet] [Masters thesis]. Virginia Tech; 2010. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/42645.

Council of Science Editors:

Hey CM. Antibody Purification from Tobacco by Protein A Affinity Chromatography. [Masters Thesis]. Virginia Tech; 2010. Available from: http://hdl.handle.net/10919/42645

Virginia Tech

18. Zhang, Wei. Microbubble fermentation of recombinant Pichia pastoris for human serum albumin production.

Degree: MS, Biological Systems Engineering, 2003, Virginia Tech

URL: http://hdl.handle.net/10919/33395

► The high cell density fermentation of recombinant Pichia pastoris for human serum albumin (HSA) production is a high oxygen demand process. The oxygen demand is… (more)

▼ The high cell density fermentation of recombinant Pichia pastoris for human serum albumin (HSA) production is a high oxygen demand process. The oxygen demand is usually met by increased agitation rate and use of oxygen-enriched air. Microbubble fermentation however can supply adequate oxygen to the microorganisms at relatively low agitation rates because of improved mass transfer of the microbubbles used for the sparging. Conventionally sparged fermentations were conducted for the production of HSA using P. pastoris at agitation rates of 350, 500, and 750 rpm, and were compared to MBD sparged fermentation at 150, 350, and 500 rpm agitation rates. The MBD improved the volumetric oxygen transfer coefficient (kLa) and subsequently increased the cell mass and protein production compared to conventional fermentation. Cell production in MBD fermentation at 350 rpm was 4.6 times higher than that in conventional fermentation at 350 rpm, but similar to that in the conventional 750 rpm. Maximum cell mass productivity in the conventional 350 rpm was only 0.37 g / (Lâ ¢h), while the maximum value in MBD 350 rpm was 2.0 g / (Lâ ¢h), which was similar to 2.2 g / (Lâ ¢h) in the conventional 750 rpm. Biomass yield on glycerol Ys (g cell/ g glycerol) was 0.334 g / g in the conventional 350 rpm, 0.431 g / g in MBD 350 rpm and 0.438 g / g in the conventional 750 rpm. Protein production in MBD 350 rpm was 7.3 times higher than that in the conventional 350 rpm, but similar to the conventional 750 rpm. Maximum protein productivity in the conventional 350 rpm was 0.37 mg / (Lâ ¢h), 2.8 mg / (Lâ ¢h) in MBD 350 rpm, and 3.3 mg / (Lâ ¢h) in the conventional 750 rpm. Protein yield on methanol Yp (mg protein / g methanol) was 1.57 mg /g in the conventional 350 rpm, 5.02 in MBD 350 rpm, and 5.21 in the conventional 750 rpm. The volumetric oxygen transfer coefficient kLa was 1011.9 h-1 in MBD 350 rpm, which was 6.1 times higher than that in the conventional 350 rpm (164.9 h-1) but was similar to the conventional 750 rpm (1098 h-1). Therefore, MBD fermentation results at low agitation of 350 rpm were similar to those in the conventional fermentation at high agitation of 750 rpm. There was considerable improvement in oxygen transfer to the microorganism using MBD sparging relative to the conventional sparging. Conventional fermentations were conducted both in a Biostat Q fermenter (small) at 500 rpm, 750 rpm, and 1000 rpm, and in a Bioflo III fermenter (large) at 350 rpm, 500 rpm, and 750 rpm. At the same agitation rate of 500 rpm, cell production in the large reactor was 3.8 times higher than that in the small one, and no detectable protein was produced in the small reactor at 500 rpm. At the same agitation rate of 750 rpm, both cell production and protein production in the large reactor were 4.6 times higher than the small reactor. Thus, the Bioflo III fermenter showed higher oxygen transfer efficiency than the Biostat Q fermenter, because of the more efficient aeration design of the Bioflo III fermenter. Advisors/Committee Members: Agblevor, Foster Aryi (committeechair), Cundiff, John S. (committee member), Zhang, Chenming Mike (committee member).

Subjects/Keywords: Pichia pastoris fermentation; oxygen transfer; human serum albumin; microbubble dispersion

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APA (6^th Edition):

Zhang, W. (2003). Microbubble fermentation of recombinant Pichia pastoris for human serum albumin production. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/33395

Chicago Manual of Style (16^th Edition):

Zhang, Wei. “Microbubble fermentation of recombinant Pichia pastoris for human serum albumin production.” 2003. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/33395.

MLA Handbook (7^th Edition):

Zhang, Wei. “Microbubble fermentation of recombinant Pichia pastoris for human serum albumin production.” 2003. Web. 18 Jan 2021.

Vancouver:

Zhang W. Microbubble fermentation of recombinant Pichia pastoris for human serum albumin production. [Internet] [Masters thesis]. Virginia Tech; 2003. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/33395.

Council of Science Editors:

Zhang W. Microbubble fermentation of recombinant Pichia pastoris for human serum albumin production. [Masters Thesis]. Virginia Tech; 2003. Available from: http://hdl.handle.net/10919/33395

Virginia Tech

19. Holler, Christopher J. Purification of an acidic recombinant protein from transgenic tobacco.

Degree: MS, Biological Systems Engineering, 2007, Virginia Tech

URL: http://hdl.handle.net/10919/32379

► Tobacco has been studied as a host for producing recombinant therapeutic proteins on a large-scale, commercial basis. However, the proteins expressed in tobacco usually need… (more)

▼ Tobacco has been studied as a host for producing recombinant therapeutic proteins on a large-scale, commercial basis. However, the proteins expressed in tobacco usually need to be purified to high yield and purity from large amounts of biomass in order for their production to be commercially viable. The methods needed to purify proteins from tobacco are very challenging and not well studied. The objective of this research was to develop a process for the purification of the acidic model protein, recombinant Î²-glucuronidase (rGUS), from transgenic tobacco leaf tissue to high yield and purity. Polyelectrolyte precipitation with polyethyleneimine (PEI) was identified as an initial purification step for purifying acidic recombinant proteins from tobacco. Polyethyleneimine precipitation allowed for high recovery and concentration of the target protein while removing large amounts of impurities from the initial extract. At dosages of 700-800 mg PEI/g total protein, nearly 100% of the rGUS activity was precipitated with generally more than 90% recovered from the pellet. In addition, more than 60% of the native tobacco proteins were removed in the process, resulting in a purification factor near 4. Recombinant GUS was further purified by a step of hydrophobic interaction chromatography (HIC) followed by a step of hydroxyapatite chromatography (HAC). The HIC step served to remove PEI and other contaminants such as nucleic acids that were accumulated during the precipitation step, while the HAC step served to separate rGUS from the remaining native tobacco proteins, most notably ribulose 1,5-bisphosphate carboxylase-oxygenase (Rubisco). Nearly 40% of the initial rGUS activity was recovered as a near homogeneous fraction based on SDS-PAGE analysis after the three step process. The main steps used in this process are anticipated to be scalable and do not rely on affinity separations, making the process potentially applicable to a wide variety of acidic recombinant proteins expressed in tobacco as well as other leafy crops. Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Helm, Richard Frederick (committee member), Agblevor, Foster Aryi (committee member).

Subjects/Keywords: liquid chromatography; protein purification; transgenic tobacco; Î²-glucuronidase; polyelectrolyte precipitation

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APA (6^th Edition):

Holler, C. J. (2007). Purification of an acidic recombinant protein from transgenic tobacco. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/32379

Chicago Manual of Style (16^th Edition):

Holler, Christopher J. “Purification of an acidic recombinant protein from transgenic tobacco.” 2007. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/32379.

MLA Handbook (7^th Edition):

Holler, Christopher J. “Purification of an acidic recombinant protein from transgenic tobacco.” 2007. Web. 18 Jan 2021.

Vancouver:

Holler CJ. Purification of an acidic recombinant protein from transgenic tobacco. [Internet] [Masters thesis]. Virginia Tech; 2007. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/32379.

Council of Science Editors:

Holler CJ. Purification of an acidic recombinant protein from transgenic tobacco. [Masters Thesis]. Virginia Tech; 2007. Available from: http://hdl.handle.net/10919/32379

Virginia Tech

20. Matanin, Brad Matthew. Purification of the major envelope protein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) from native virions.

Degree: MS, Biological Systems Engineering, 2007, Virginia Tech

URL: http://hdl.handle.net/10919/33194

► Porcine reproductive and respiratory syndrome virus (PRRSV) is the cause of a pandemic that has been devastating the U.S. and global swine industry for more… (more)

Subjects/Keywords: detergent solubilization; protein purification; GP5; chromatography; PRRSV; virus culture

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APA (6^th Edition):

Matanin, B. M. (2007). Purification of the major envelope protein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) from native virions. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/33194

Chicago Manual of Style (16^th Edition):

Matanin, Brad Matthew. “Purification of the major envelope protein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) from native virions.” 2007. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/33194.

MLA Handbook (7^th Edition):

Matanin, Brad Matthew. “Purification of the major envelope protein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) from native virions.” 2007. Web. 18 Jan 2021.

Vancouver:

Matanin BM. Purification of the major envelope protein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) from native virions. [Internet] [Masters thesis]. Virginia Tech; 2007. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/33194.

Council of Science Editors:

Matanin BM. Purification of the major envelope protein GP5 of porcine reproductive and respiratory syndrome virus (PRRSV) from native virions. [Masters Thesis]. Virginia Tech; 2007. Available from: http://hdl.handle.net/10919/33194

Virginia Tech

21. Ross, Kristin Coby. Separation of Recombinant β-Glucuronidase from Transgenic Tobacco by Aqueous Two-Phase Extraction.

Degree: MS, Biological Systems Engineering, 2008, Virginia Tech

URL: http://hdl.handle.net/10919/43471

► Biopharmaceutical manufacturing is a rigorous and expensive process. Due to the medicinal nature of the product, a high purity level is required and several expensive… (more)

Subjects/Keywords: transgenic tobacco; recombinant β-glucuronidase; aqueous two-phase extraction; protein purification

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APA (6^th Edition):

Ross, K. C. (2008). Separation of Recombinant β-Glucuronidase from Transgenic Tobacco by Aqueous Two-Phase Extraction. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/43471

Chicago Manual of Style (16^th Edition):

Ross, Kristin Coby. “Separation of Recombinant β-Glucuronidase from Transgenic Tobacco by Aqueous Two-Phase Extraction.” 2008. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/43471.

MLA Handbook (7^th Edition):

Ross, Kristin Coby. “Separation of Recombinant β-Glucuronidase from Transgenic Tobacco by Aqueous Two-Phase Extraction.” 2008. Web. 18 Jan 2021.

Vancouver:

Ross KC. Separation of Recombinant β-Glucuronidase from Transgenic Tobacco by Aqueous Two-Phase Extraction. [Internet] [Masters thesis]. Virginia Tech; 2008. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/43471.

Council of Science Editors:

Ross KC. Separation of Recombinant β-Glucuronidase from Transgenic Tobacco by Aqueous Two-Phase Extraction. [Masters Thesis]. Virginia Tech; 2008. Available from: http://hdl.handle.net/10919/43471

Virginia Tech

22. Buswell, Walter Scott. Expression of recombinant porcine preprorelaxin in Nicotiana tabacum.

Degree: MS, Biological Systems Engineering, 2006, Virginia Tech

URL: http://hdl.handle.net/10919/32803

► Relaxin is a small peptide hormone that has demonstrated potential therapeutic actions for cardiovascular disease and fibrosis. Additionally, relaxin has demonstrated the ability to protect… (more)

Subjects/Keywords: recombinant protein; transgenic tobacco; relaxin

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APA (6^th Edition):

Buswell, W. S. (2006). Expression of recombinant porcine preprorelaxin in Nicotiana tabacum. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/32803

Chicago Manual of Style (16^th Edition):

Buswell, Walter Scott. “Expression of recombinant porcine preprorelaxin in Nicotiana tabacum.” 2006. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/32803.

MLA Handbook (7^th Edition):

Buswell, Walter Scott. “Expression of recombinant porcine preprorelaxin in Nicotiana tabacum.” 2006. Web. 18 Jan 2021.

Vancouver:

Buswell WS. Expression of recombinant porcine preprorelaxin in Nicotiana tabacum. [Internet] [Masters thesis]. Virginia Tech; 2006. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/32803.

Council of Science Editors:

Buswell WS. Expression of recombinant porcine preprorelaxin in Nicotiana tabacum. [Masters Thesis]. Virginia Tech; 2006. Available from: http://hdl.handle.net/10919/32803

Virginia Tech

23. Shi, Wenjuan. Examination of the Effects of a Sphingolipid-Enriched Lipid Fraction from Wheat Gluten on the Incidence of Diabetes in BBdp Rats.

Degree: MS, Human Nutrition, Foods, and Exercise, 2004, Virginia Tech

URL: http://hdl.handle.net/10919/30927

► This study was designed to examine if a sphingolipid-enriched lipid fraction from wheat gluten could affect the incidence of type I diabetes in BioBreeding diabetes… (more)

▼ This study was designed to examine if a sphingolipid-enriched lipid fraction from wheat gluten could affect the incidence of type I diabetes in BioBreeding diabetes prone (BBdp) rats. Wheat gluten was extracted with a chloroform-methanol (CM) mixture to isolate most of the lipids. Isolated lipids were subjected to silica gel column chromatography and saponification to remove most of neutral lipids and phospholipids, leaving behind a lipid fraction enriched in sphingolipids. This sphingolipid-enriched lipid fraction was used in a BBdp rat feeding study. BBdp rats were fed with one of five diets from weaning at 23 days of age until 125 days of age: a hydrolyzed casein based diet (HC), a NTP-2000 standard rodent diet (NTP-2000), a wheat gluten based diet (WG), a sphingolipid-free wheat gluten based diet (WGSLF), and a hydrolyzed casein plus sphingolipid-enriched lipid fraction diet (HC+SL). The yield of sphingolipid-enriched lipid fraction was about 0.62% of wheat gluten. The content of glycosylceramide in sphingolipid-enriched lipid fraction was increased more than five fold compared to that in total isolated lipids. Rats fed the NTP-2000 diet had the highest incidence of diabetes; while rats on the HC diet had the lowest diabetes incidence. There was no significant difference with regard to the onset age of diabetes among rats in the five diet groups. The addition of sphingolipid-enriched fraction to the HC diet caused a significant increase in the incidence of diabetes in BBdp rats in the first 80 days of the study. However, the ultimate diabetes incidence at day 125 was not changed. The removal of lipids from wheat gluten did not change the diabetes incidence in BBdp rats at any stages of the feeding study. These findings suggest that the sphingolipid-enriched fraction from wheat gluten acted as a possible promoter but not as a trigger of the development of type I diabetes in BBdp rats. There must be something that remains in wheat gluten after chloroform-methanol extraction that serves as a trigger for type I diabetes in these rodents. Type I diabetes in this animal model for the human disease seems to be caused by multiple factors, most likely, by the interaction of sphingolipids and some other unknown substances in wheat gluten. Advisors/Committee Members: Barbeau, William E. (committeechair), Zhang, Chenming Mike (committee member), Nickols-Richardson, Sharon M. (committee member).

Subjects/Keywords: Sphingolipids; BBdp rats; Type I diabetes; Wheat gluten

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APA (6^th Edition):

Shi, W. (2004). Examination of the Effects of a Sphingolipid-Enriched Lipid Fraction from Wheat Gluten on the Incidence of Diabetes in BBdp Rats. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/30927

Chicago Manual of Style (16^th Edition):

Shi, Wenjuan. “Examination of the Effects of a Sphingolipid-Enriched Lipid Fraction from Wheat Gluten on the Incidence of Diabetes in BBdp Rats.” 2004. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/30927.

MLA Handbook (7^th Edition):

Shi, Wenjuan. “Examination of the Effects of a Sphingolipid-Enriched Lipid Fraction from Wheat Gluten on the Incidence of Diabetes in BBdp Rats.” 2004. Web. 18 Jan 2021.

Vancouver:

Shi W. Examination of the Effects of a Sphingolipid-Enriched Lipid Fraction from Wheat Gluten on the Incidence of Diabetes in BBdp Rats. [Internet] [Masters thesis]. Virginia Tech; 2004. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/30927.

Council of Science Editors:

Shi W. Examination of the Effects of a Sphingolipid-Enriched Lipid Fraction from Wheat Gluten on the Incidence of Diabetes in BBdp Rats. [Masters Thesis]. Virginia Tech; 2004. Available from: http://hdl.handle.net/10919/30927

Virginia Tech

24. Ballard, Tameshia Shaunt'a. Optimizing the Extraction of Phenolic Antioxidant Compounds from Peanut Skins.

Degree: PhD, Biological Systems Engineering, 2008, Virginia Tech

URL: http://hdl.handle.net/10919/28349

► Peanut skins are a low-value byproduct of peanut blanching operations. They have been shown to contain significant levels of phenolic compounds with demonstrated antioxidant properties.… (more)

▼ Peanut skins are a low-value byproduct of peanut blanching operations. They have been shown to contain significant levels of phenolic compounds with demonstrated antioxidant properties. The effects of two types of extraction methods: solid-liquid extraction (SLE) and microwave-assisted extraction (MAE) on the recovery of phenolic compounds from peanut skins were investigated. Response surface methodology was used to optimize extraction conditions based on total phenolic content (TPC), ORAC (oxygen radical absorbance capacity) activity and <i>trans</i>-resveratrol content. The protective effect of peanut skin extracts (PSE) against hydrogen peroxide (H₂O₂)-induced oxidative stress in human brain microvascular endothelial cells (HBMEC) and the effect of PSE on lipid oxidation in commercial peanut butter were also evaluated. In the SLE method, EtOH was found to be the most efficient extraction solvent followed by MeOH, water and EA. Despite EtOH extracts having a higher TPC, samples extracted with MeOH demonstrated slightly higher ORAC activity. Resveratrol was identified in MeOH extracts but was not found in EtOH, water or EA extracts. In the MAE procedure, the maximum predicted TPC under the optimized conditions was 144 mg phenols/g skins compared to 118 mg/g with SLE. The maximum predicted ORAC activity was 2789 μmol TE/g as opposed to 2149 μmol TE/g with the SLE method. MAE was able to extract more phenolic compounds (with higher antioxidant activity) in a faster time than the SLE procedure. In addition, resveratrol was identified in PSE derived from MAE although at relatively low levels. PSE were found to have some protective effects against oxidative stress in HBMEC. Higher doses of PSE appeared to have a slightly cytotoxic effect. However, the data were highly variable which made it difficult to arrive at any definitive conclusions regarding the potential benefits of PSE in preventing oxidative damage to cells. In the PB experiment, hexanal levels over the storage period were not high enough for the samples to be considered oxidized. However, hexanal values of PB samples treated with PSE were lower than the control throughout storage, which suggests that PSE may provide some protection against oxidation of PB. Advisors/Committee Members: Mallikarjunan, Parameswarakumar (committeechair), Thatcher, Craig (committee member), Zhang, Chenming Mike (committee member), O'Keefe, Sean F. (committeecochair).

Subjects/Keywords: microwave-assisted extraction; response surface methodology; peanut skins; antioxidants; polyphenols; resveratrol; solid-liquid extraction; human brain microvascular endothelial cells; peanut butter

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APA (6^th Edition):

Ballard, T. S. (2008). Optimizing the Extraction of Phenolic Antioxidant Compounds from Peanut Skins. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/28349

Chicago Manual of Style (16^th Edition):

Ballard, Tameshia Shaunt'a. “Optimizing the Extraction of Phenolic Antioxidant Compounds from Peanut Skins.” 2008. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/28349.

MLA Handbook (7^th Edition):

Ballard, Tameshia Shaunt'a. “Optimizing the Extraction of Phenolic Antioxidant Compounds from Peanut Skins.” 2008. Web. 18 Jan 2021.

Vancouver:

Ballard TS. Optimizing the Extraction of Phenolic Antioxidant Compounds from Peanut Skins. [Internet] [Doctoral dissertation]. Virginia Tech; 2008. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/28349.

Council of Science Editors:

Ballard TS. Optimizing the Extraction of Phenolic Antioxidant Compounds from Peanut Skins. [Doctoral Dissertation]. Virginia Tech; 2008. Available from: http://hdl.handle.net/10919/28349

Virginia Tech

25. Athamneh, Ahmad Ibrahim. Peptide Self-Assembly from the Molecular to the Macroscopic Scale at Standard Conditions.

Degree: PhD, Biological Systems Engineering, 2010, Virginia Tech

URL: http://hdl.handle.net/10919/29789

► This dissertation attempts to address the problem of how to prepare protein-based materials with the same level of order and precision at the molecular level… (more)

▼ This dissertation attempts to address the problem of how to prepare protein-based materials with the same level of order and precision at the molecular level similar to the structures we find in nature. It is divided into two parts focusing on feedstock and processing. Part one is devoted to discussing the use of agricultural proteins as a feedstock for material production. Particularly, it focuses on the effect of hydrogen bonding, or lack thereof, between proteins as mediated by hydration or plasticization. The effect of varying plasticizer (glycerol) levels on mechanical properties of a series of proteins is discussed in the context of primary and secondary structure of these proteins. We have found that the extent to which a protein can be plasticized is dependent on its molecular and higher order structure and not simply molecular weight, as it was often assumed in previous studies. The second part of the dissertation focuses on the study of self-assembly as a way to make useful peptide-based materials. There are major efforts underway to study protein self-assembly for various medical and industrial reasons. Despite huge progress, most studies have focused on nanoscale self-assembly but the crossover to the macroscopic scale remains a challenge. We show that peptide self-assembly into macroscopic fibers is possible in vitro under physiological conditions. We characterize the fibers and propose a mechanism by which they form. The macroscopic fibers self-assemble from a combination of β- and α-peptides and are similar to other naturally-occurring systems in which templated self-assembly is used to create functional peptide materials. Finally, the ability to control macroscopic properties of the fiber by varying the ratio of constituent peptides is demonstrated. Owing to the richness of the amino acid building blocks, peptides are highly versatile structural and functional building blocks. The ability to extend and control peptide self-assembly over multiple length scales is a significant leap toward incorporating peptide materials into dynamic systems of higher complexity and functionality. Advisors/Committee Members: Barone, Justin R. (committeechair), Zhang, Chenming Mike (committee member), Senger, Ryan S. (committee member), Morgan, Abby W. (committee member).

Subjects/Keywords: plasticized biopolymers; nanomaterials; multiscale self-assembly; peptide materials

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APA (6^th Edition):

Athamneh, A. I. (2010). Peptide Self-Assembly from the Molecular to the Macroscopic Scale at Standard Conditions. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/29789

Chicago Manual of Style (16^th Edition):

Athamneh, Ahmad Ibrahim. “Peptide Self-Assembly from the Molecular to the Macroscopic Scale at Standard Conditions.” 2010. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/29789.

MLA Handbook (7^th Edition):

Athamneh, Ahmad Ibrahim. “Peptide Self-Assembly from the Molecular to the Macroscopic Scale at Standard Conditions.” 2010. Web. 18 Jan 2021.

Vancouver:

Athamneh AI. Peptide Self-Assembly from the Molecular to the Macroscopic Scale at Standard Conditions. [Internet] [Doctoral dissertation]. Virginia Tech; 2010. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/29789.

Council of Science Editors:

Athamneh AI. Peptide Self-Assembly from the Molecular to the Macroscopic Scale at Standard Conditions. [Doctoral Dissertation]. Virginia Tech; 2010. Available from: http://hdl.handle.net/10919/29789

Virginia Tech

26. Budhavaram, Naresh Kumar. Facile protein and amino acid substitution reactions and their characterization using thermal, mechanical and optical techniques.

Degree: PhD, Biological Systems Engineering, 2010, Virginia Tech

URL: http://hdl.handle.net/10919/40340

► The work focused on addressing four main objectives. The first objective was to quantify protein and amino acid substitution reactions. Michael addition reactions were used… (more)

▼ The work focused on addressing four main objectives. The first objective was to quantify protein and amino acid substitution reactions. Michael addition reactions were used to modify the amino acids and protein. Amino acids alanine, cysteine, and lysine, and protein ovalbumin (OA) were substituted with different concentrations of ethyl vinyl sulfone (EVS). The substituted products were analyzed using Raman spectroscopy and UV-spectroscopy based ninhydrin assay. In case of alanine, Raman and UV results correlated with each other. With cysteine at lower EVS substitutions amine on the main chain was the preferred site while the substitution shifted to thiols at higher substitutions. This could only be discerned using Raman spectroscopy. Lysine has amines on the main chain and side chain while main chain amine was the most reactive site at lower concentrations of EVS while at higher concentrations side chain amines were also substituted. This information could be discerned using Raman spectroscopy only and not UV spectroscopy. In case of protein as observed by Raman and UV spectroscopy the reaction continued at higher concentrations of EVS indicating the participation of glutamine and asparagines at higher substitutions. However, the reaction considerably slowed down at higher EVS substitutions. The second objective of the study was to decrease the glass transition temperature (Tg) of OA through internal plasticization and also study the effects of the substituents on the thermal stability of OA. The hypothesis was by covalently attaching substituents to OA, number of hydrogen bonds can be reduced while increasing the free volume and this would reduce Tg. EVS, acrylic acid (AA), butadiene sulfone (BS) and maleimide (MA) were the four groups used. EVS was the most efficient plasticizer of all the four substituents. The Tg decreased with the increasing concentration of EVS until all of the reactive of groups on OA were used up. Tg decreased slightly with AA and BS while no change was observed with MA. However, the substituents showed exact opposite trend in thermal stability as measured using thermogravimetric analysis (TGA). The thermal stability of MA substituted OA was the highest and that of EVS substituted OA was least. FT-IR spectroscopy results indicated that all four substituents caused structural changes in OA. This implied that there were intermolecular interactions between substituted protein chains in case of AA, BS, and MA. This caused an increase in the thermal stability. EVS on the other hand is a linear chain monomer with a hydrophobic end group and hence could not participate in the intermolecular interactions and hence caused a decrease in Tg. As mentioned above the limitation to this technique is the number of available reactive groups on the protein. However, we successfully demonstrated the feasibility of this method in decreasing Tg of protein. The third objective was to create hydrogels by crosslinking OA with divinyl sulfone (DVS). Protein hydrogels due to their biocompatible nature find… Advisors/Committee Members: Barone, Justin R. (committeechair), Madsen, Louis A. (committee member), Wen, Zhiyou (committee member), Zhang, Chenming Mike (committee member).

Subjects/Keywords: Glass Transition Temperature; Hydrogels; Michael Addition Reactions; Raman Spectroscopy; Fibers; Microtubes.; Cysteine; Alanine; Lysine; Ovalbumin

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APA (6^th Edition):

Budhavaram, N. K. (2010). Facile protein and amino acid substitution reactions and their characterization using thermal, mechanical and optical techniques. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/40340

Chicago Manual of Style (16^th Edition):

Budhavaram, Naresh Kumar. “Facile protein and amino acid substitution reactions and their characterization using thermal, mechanical and optical techniques.” 2010. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/40340.

MLA Handbook (7^th Edition):

Budhavaram, Naresh Kumar. “Facile protein and amino acid substitution reactions and their characterization using thermal, mechanical and optical techniques.” 2010. Web. 18 Jan 2021.

Vancouver:

Budhavaram NK. Facile protein and amino acid substitution reactions and their characterization using thermal, mechanical and optical techniques. [Internet] [Doctoral dissertation]. Virginia Tech; 2010. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/40340.

Council of Science Editors:

Budhavaram NK. Facile protein and amino acid substitution reactions and their characterization using thermal, mechanical and optical techniques. [Doctoral Dissertation]. Virginia Tech; 2010. Available from: http://hdl.handle.net/10919/40340

Virginia Tech

27. Shah, Kinjalkumar K. Design, Synthesis and Characterization of Heme-proteins: Developing Potential Catalysts for Bio-remediation.

Degree: MS, Biological Systems Engineering, 2004, Virginia Tech

URL: http://hdl.handle.net/10919/31187

► The next generation of toxic chemicals and hazardous wastes from sophisticated chemical industries will demand the environmental agencies to employ biological methods over the conventional… (more)

Subjects/Keywords: Peroxidase activity; Cytochrome b562; Protein design; Hemeprotein; Solid phase peptide synthesis; Four-helix bundle protein

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APA (6^th Edition):

Shah, K. K. (2004). Design, Synthesis and Characterization of Heme-proteins: Developing Potential Catalysts for Bio-remediation. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/31187

Chicago Manual of Style (16^th Edition):

Shah, Kinjalkumar K. “Design, Synthesis and Characterization of Heme-proteins: Developing Potential Catalysts for Bio-remediation.” 2004. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/31187.

MLA Handbook (7^th Edition):

Shah, Kinjalkumar K. “Design, Synthesis and Characterization of Heme-proteins: Developing Potential Catalysts for Bio-remediation.” 2004. Web. 18 Jan 2021.

Vancouver:

Shah KK. Design, Synthesis and Characterization of Heme-proteins: Developing Potential Catalysts for Bio-remediation. [Internet] [Masters thesis]. Virginia Tech; 2004. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/31187.

Council of Science Editors:

Shah KK. Design, Synthesis and Characterization of Heme-proteins: Developing Potential Catalysts for Bio-remediation. [Masters Thesis]. Virginia Tech; 2004. Available from: http://hdl.handle.net/10919/31187

Virginia Tech

28. Balasubramaniam, Deepa. Lysozyme Separation from Tobacco Extract by Aqueous Two-Phase Extraction.

Degree: MS, Biological Systems Engineering, 2003, Virginia Tech

URL: http://hdl.handle.net/10919/31272

► Tobacco has long been considered as a host to produce large quantities of high-valued recombinant proteins. However, dealing with large quantities of biomass with a… (more)

▼ Tobacco has long been considered as a host to produce large quantities of high-valued recombinant proteins. However, dealing with large quantities of biomass with a dilute concentration of product is a challenge for down-stream processing. Aqueous two-phase extraction (ATPE) has been used in purifying proteins from various sources. It is a protein-friendly process and can be scaled up easily. ATPE was studied for its applicability to recombinant protein purification from tobacco using egg white lysozyme as the model protein. Separate experiments with polyethyleneglycol(PEG)/salt/tobacco extract, and PEG/salt/lysozyme were carried out to determine the partition behavior of tobacco protein and lysozyme, respectively. Two level fractional factorial designs were used to study the effects of factors such as PEG molecular weight, PEG concentration, the concentration of phase forming salt, sodium chloride concentration, and pH on protein partitioning. The results showed that PEG/sodium sulfate system was most suitable for lysozyme purification. Detailed experiments were conducted by spiking lysozyme into the tobacco extract. The conditions with highest selectivity of lysozyme over native tobacco protein were determined using a response surface design. The purification factor was further improved by decreasing the phase ratio along the tie line corresponding to the phase compositions with the highest selectivity. Under selected conditions the lysozyme yield was predicted to be 87% with a purification factor of 4 and concentration factor of 14. The binodial curve and tie line corresponding to the optimal condition for lysozyme recovery for the PEG 3400/sodium sulfate system were developed. The selectivity at the optimal condition was experimentally determined to be 47 with a lysozyme yield of 79.6 % with a purification factor of 10 and a concentration factor of 20. From this study, ATPE was shown to be suitable for initial protein recovery and partial purification from transgenic tobacco. Advisors/Committee Members: Zhang, Chenming Mike (committeechair), Agblevor, Foster Aryi (committee member), Van Cott, Kevin E. (committee member), Cundiff, John S. (committee member).

Subjects/Keywords: Lysozyme; Tobacco; Protein Purification; Aqueous Two-phase extraction

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Balasubramaniam, D. (2003). Lysozyme Separation from Tobacco Extract by Aqueous Two-Phase Extraction. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/31272

Chicago Manual of Style (16^th Edition):

Balasubramaniam, Deepa. “Lysozyme Separation from Tobacco Extract by Aqueous Two-Phase Extraction.” 2003. Masters Thesis, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/31272.

MLA Handbook (7^th Edition):

Balasubramaniam, Deepa. “Lysozyme Separation from Tobacco Extract by Aqueous Two-Phase Extraction.” 2003. Web. 18 Jan 2021.

Vancouver:

Balasubramaniam D. Lysozyme Separation from Tobacco Extract by Aqueous Two-Phase Extraction. [Internet] [Masters thesis]. Virginia Tech; 2003. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/31272.

Council of Science Editors:

Balasubramaniam D. Lysozyme Separation from Tobacco Extract by Aqueous Two-Phase Extraction. [Masters Thesis]. Virginia Tech; 2003. Available from: http://hdl.handle.net/10919/31272

Virginia Tech

29. Jin, Ying. Microwave-based Pretreatment, Pathogen Fate and Microbial Population in a Dairy Manure Treatment System.

Degree: PhD, Biological Systems Engineering, 2010, Virginia Tech

URL: http://hdl.handle.net/10919/77287

► Anaerobic digestion and struvite precipitation are two effective ways of treating dairy manure for recovering biogas and phosphorus. Anaerobic digestion of dairy manure is commonly… (more)

▼ Anaerobic digestion and struvite precipitation are two effective ways of treating dairy manure for recovering biogas and phosphorus. Anaerobic digestion of dairy manure is commonly limited by slow fiber degradation, while one of the limitations to struvite precipitation is the availability of orthophosphate. The aim of this work was to study the use of microwave-based thermochemical pretreatment to simultaneously enhance manure anaerobic digestibility (through fiber degradation) and struvite precipitation (through phosphorus solubilization). Microwave heating combined with different chemicals (NaOH, CaO, H₂SO₄, or HCl) enhanced solubilization of manure and degradation of glucan/xylan in dairy manure. However, sulfuric acid-based pretreatment resulted in a low anaerobic digestibility, probably due to the sulfur inhibition and side reactions. The pretreatments released 20-40% soluble phosphorus and 9-14% ammonium. However, CaO-based pretreatment resulted in lower orthophosphate releases and struvite precipitation efficiency as calcium reacts with phosphate to form calcium phosphate. Collectively, microwave heating combined with NaOH or HCl led to a high anaerobic digestibility and phosphorus recovery. Using these two chemicals, the performance of microwave- and conventional-heating in thermochemical pretreatment was further compared. The microwave heating resulted in a better performance in terms of COD solubilization, glucan/xylan reduction, phosphorus solubilization and anaerobic digestibility. Lastly, temperature and heating time used in microwave treatment were optimized. The optimal values of temperature and heating time were 147°C and 25.3 min for methane production, and 135°C and 26 min for orthophosphate release, respectively. Applying manure or slurry directly to the land can contribute to pathogen contamination of land, freshwater and groundwater. Thus it is important to study the fate of pathogens in diary manure anaerobic digestion systems. The goal of the project was to establish a molecular based quantitative method for pathogen identification and quantification, compare the molecular based method with culture based method and study pathogen fate in dairy manure and different anaerobic digesters. Result showed that molecular based method detected more E.coli than the culture based method with less variability. Thermophilic anaerobic digestion can achieve more than 95% pathogen removal rate while mesophilic anaerobic digester had increased E.coli number than fresh manure, indicating temperature is a key factor for pathogen removal. In general, the overall goal of the study is to develop an integrated dairy manure treatment system. The microwave based pretreatment enhanced the subsequent biogas production and struvite precipitation, and the molecular tool based method provided a more precise and faster way to study the pathogen fate in various anaerobic digestions. Advisors/Committee Members: Wen, Zhiyou (committeechair), Zhang, Chenming Mike (committee member), Ogejo, Jactone Arogo (committee member), Knowlton, Katharine F. (committee member).

Subjects/Keywords: dairy manure; microwave; pre-treatment; pathogen; q-PCR; anaerobic digestion

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Jin, Y. (2010). Microwave-based Pretreatment, Pathogen Fate and Microbial Population in a Dairy Manure Treatment System. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/77287

Chicago Manual of Style (16^th Edition):

Jin, Ying. “Microwave-based Pretreatment, Pathogen Fate and Microbial Population in a Dairy Manure Treatment System.” 2010. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/77287.

MLA Handbook (7^th Edition):

Jin, Ying. “Microwave-based Pretreatment, Pathogen Fate and Microbial Population in a Dairy Manure Treatment System.” 2010. Web. 18 Jan 2021.

Vancouver:

Jin Y. Microwave-based Pretreatment, Pathogen Fate and Microbial Population in a Dairy Manure Treatment System. [Internet] [Doctoral dissertation]. Virginia Tech; 2010. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/77287.

Council of Science Editors:

Jin Y. Microwave-based Pretreatment, Pathogen Fate and Microbial Population in a Dairy Manure Treatment System. [Doctoral Dissertation]. Virginia Tech; 2010. Available from: http://hdl.handle.net/10919/77287

Virginia Tech

30. Shen, Jiacheng. Modeling and Production of Bioethanol from Mixtures of Cotton Gin Waste and Recycled Paper Sludge.

Degree: PhD, Biological Systems Engineering, 2008, Virginia Tech

URL: http://hdl.handle.net/10919/30264

► In this study, the hydrolytic kinetics of mixtures of cotton gin waste (CGW) and recycled paper sludge (RPS) at various initial enzyme concentrations of Spezyme… (more)

▼ In this study, the hydrolytic kinetics of mixtures of cotton gin waste (CGW) and recycled paper sludge (RPS) at various initial enzyme concentrations of Spezyme AO3117 and Novozymes NS50052 was investigated. The experiments showed that the concentrations of reducing sugars and the conversions of the mixtures increased with increasing initial enzyme concentration. The reducing sugar concentration and conversion of the mixture of 75% CGW and 25% RPS were higher than those of the mixture of 80% CGW and 20% RPS. The conversion of the former could reach 73.8% after a 72-hour hydrolysis at the initial enzyme loading of 17.4 Filter Paper Unit (FPU)/g substrate. A three-parameter kinetic model with convergent property based on enzyme deactivation and its analytical expression were derived. Using nonlinear regression, the parameters of the model were determined from the experimental data of hydrolytic kinetics of the mixtures. Based on this kinetic model of hydrolysis, two profit rate models, representing two kinds of operating modes with and without substrate recycling, were developed. Using the profit rate models, the optimal enzyme loading and hydrolytic time could be predicted for the maximum profit rate in ethanol production according to the costs of enzyme and operation, enzyme loading, and ethanol market price. Simulated results from the models based on the experimental data of hydrolysis of the mixture of 75% CGW and 25% RPS showed that use of a high substrate concentration and an operating mode with feedstock recycle could greatly increase the profit rate of ethanol production. The results also demonstrated that the hydrolysis at a low enzyme loading was economically required for systematic optimization of ethanol production. The development of profit rate model points out a way to optimize a monotonic function with variables, such as enzyme loading and hydrolytic time for the maximum profit rate. The study also investigated the ethanol production from the steam-exploded mixture of 75 wt% cotton gin waste and 25 wt% recycled paper sludge at various influencing factors, such as enzyme concentration, substrate concentration, and severity factor, by a novel operating mode: semi-simultaneous saccharification and fermentation (SSSF) consisting of a pre-hydrolysis and a simultaneous saccharification and fermentation (SSF). Four cases were studied: 24-hour pre-hydrolysis + 48-hour SSF (SSSF 24), 12-hour pre-hydrolysis + 60-hour SSF (SSSF 12), 72-hour SSF, and 48-hour hydrolysis + 12-hour fermentation (SHF). SSSF 24 produced higher ethanol concentration, yield, and productivity than the other operating modes. The higher temperature of steam explosion favored of ethanol production, but the higher initial enzyme concentration could not increase the final ethanol concentration though the hydrolytic rate of the substrate was increased. A mathematical model of SSSF, which consisted of an enzymatic hydrolysis model and a SSF model including four ordinary differential equations that describe the changes of cellobiose, glucose,… Advisors/Committee Members: Agblevor, Foster Aryi (committeechair), Wen, Zhiyou (committee member), Zhang, Chenming Mike (committee member), Barbeau, William E. (committee member), Helm, Richard Frederick (committee member).

Subjects/Keywords: Profit rate; Diffusivity.; Kinetic model; Simultaneous saccharification and fermentation; Enzymatic hydrolysis; Ethanol; Cellulose; Deactivation; Operating mode; Recycled paper sludge; Cotton gin waste

Record Details Similar Records Cite « Share

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Shen, J. (2008). Modeling and Production of Bioethanol from Mixtures of Cotton Gin Waste and Recycled Paper Sludge. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/30264

Chicago Manual of Style (16^th Edition):

Shen, Jiacheng. “Modeling and Production of Bioethanol from Mixtures of Cotton Gin Waste and Recycled Paper Sludge.” 2008. Doctoral Dissertation, Virginia Tech. Accessed January 18, 2021. http://hdl.handle.net/10919/30264.

MLA Handbook (7^th Edition):

Shen, Jiacheng. “Modeling and Production of Bioethanol from Mixtures of Cotton Gin Waste and Recycled Paper Sludge.” 2008. Web. 18 Jan 2021.

Vancouver:

Shen J. Modeling and Production of Bioethanol from Mixtures of Cotton Gin Waste and Recycled Paper Sludge. [Internet] [Doctoral dissertation]. Virginia Tech; 2008. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10919/30264.

Council of Science Editors:

Shen J. Modeling and Production of Bioethanol from Mixtures of Cotton Gin Waste and Recycled Paper Sludge. [Doctoral Dissertation]. Virginia Tech; 2008. Available from: http://hdl.handle.net/10919/30264

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