subject:(Acetic acid tolerance)

Georgia Tech

1. Wang, Yun. Development of acetic-acid tolerant Zymomonas mobilis strains through adaptation.

Degree: MS, Chemical Engineering, 2008, Georgia Tech

► Zymomonas mobilis is one of the most promising microorganisms for bioethanol production. However, its practical use on industrial scale is impeded by its high sensitivity… (more)

Subjects/Keywords: Adaptive mutation; Zymomonas; Acetic acid tolerance; Acetic acid; Microorganisms; Alcohol; Fermentation

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

APA (6^th Edition):

Wang, Y. (2008). Development of acetic-acid tolerant Zymomonas mobilis strains through adaptation. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/29747

Chicago Manual of Style (16^th Edition):

Wang, Yun. “Development of acetic-acid tolerant Zymomonas mobilis strains through adaptation.” 2008. Masters Thesis, Georgia Tech. Accessed January 19, 2021. http://hdl.handle.net/1853/29747.

MLA Handbook (7^th Edition):

Wang, Yun. “Development of acetic-acid tolerant Zymomonas mobilis strains through adaptation.” 2008. Web. 19 Jan 2021.

Vancouver:

Wang Y. Development of acetic-acid tolerant Zymomonas mobilis strains through adaptation. [Internet] [Masters thesis]. Georgia Tech; 2008. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/1853/29747.

Council of Science Editors:

Wang Y. Development of acetic-acid tolerant Zymomonas mobilis strains through adaptation. [Masters Thesis]. Georgia Tech; 2008. Available from: http://hdl.handle.net/1853/29747

University of Illinois – Urbana-Champaign

2. Si, Tong. An RNA-interference-based platform for genome analysis and engineering in Saccharomyces cerevisiae.

Degree: MS, 0300, 2013, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/44817

► Efficient microbial production of fuels and chemicals from lignocellulosic feedstock requires intensive reprogramming of cellular machinery. Given our limited knowledge of the complex biological systems,… (more)

▼ Efficient microbial production of fuels and chemicals from lignocellulosic feedstock requires intensive reprogramming of cellular machinery. Given our limited knowledge of the complex biological systems, such tasks prove to be better fulfilled with directed evolution than with rational design, by performing iterative cycles of mutagenesis and selection. However, the success of directed evolution is mostly confined to individual proteins, due to the lack of efficient tools to introduce mutations globally and iteratively on a genome scale. Thanks to its simplicity and effectiveness, the pooled RNA interference (RNAi) screening should satisfy the requirement of directed genome evolution. The RNAi pathway is absent in Saccharomyces cerevisiae, also known as the baker’s yeast. Recently, functional RNAi machinery has been reconstituted in this eukaryotic model, upon the introduction of Dicer and Argonaute proteins from a related species Saccharomyces castellii. We first explored the possibility of applying RNAi screening in S. cerevisiae. The design of convergent promoters was adapted to drive the in vivo synthesis of double strand RNAs (dsRNA), which were further processed as small interference RNAs (siRNA) to mediate the knockdown of homologous genes. A plasmid-based dsRNA library was constructed from enzymatically digested genomic DNA based on convergent-promoter design. The library was confirmed to achieve a nearly complete (>99.75%) coverage of yeast genome, and was employed to perform a suppressor analysis of the yku70 knockout. A colony-size based screening method was used to identify two known and three novel knockdown modifications that can alleviate the growth arrest of the Δyku70 strain at higher temperature. Further analysis confirmed that these genes are indeed the modulators of the Δyku70 phenotype. Encouraged by these results, we further developed an efficient, genome-scale and generally applicable method for eukaryotic reprogramming, RNAi-Assisted Genome Evolution (RAGE). In each round of RAGE, one knockdown modification conferring desired trait was identified by RNAi screening. The best knockdown cassette was integrated into the chromosome to create a new strain, serving as the parent strain for the next round of RAGE. Repeated cycles of RAGE accumulated the beneficial genetic modifications in the host genome, and thus continuously improve the target properties. As proof-of-concept, RAGE was applied to improve acetic acid (HAc) tolerance of S. cerevisiae. After three rounds, the 100% growth inhibition concentration of HAc was elevated from 0.7% to 0.9% (v/v). The best engineered strain exhibited a significantly improved fermentation performance than the wild type strain under HAc stress. By combining the powerful toolboxes of RNAi and directed evolution, RAGE may greatly accelerate the design and evolution of organisms with desired traits and provide new insights on genome structure, function, and evolution. Advisors/Committee Members: Zhao, Huimin (advisor).

Subjects/Keywords: RNA interference; high-throughput screening; directed evolution; Genome Engineering; Saccharomyces cerevisiae; suppressor analysis; telomere; acetic acid tolerance

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

APA (6^th Edition):

Si, T. (2013). An RNA-interference-based platform for genome analysis and engineering in Saccharomyces cerevisiae. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/44817

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Si, Tong. “An RNA-interference-based platform for genome analysis and engineering in Saccharomyces cerevisiae.” 2013. Thesis, University of Illinois – Urbana-Champaign. Accessed January 19, 2021. http://hdl.handle.net/2142/44817.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Si, Tong. “An RNA-interference-based platform for genome analysis and engineering in Saccharomyces cerevisiae.” 2013. Web. 19 Jan 2021.

Vancouver:

Si T. An RNA-interference-based platform for genome analysis and engineering in Saccharomyces cerevisiae. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2013. [cited 2021 Jan 19]. Available from: http://hdl.handle.net/2142/44817.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Si T. An RNA-interference-based platform for genome analysis and engineering in Saccharomyces cerevisiae. [Thesis]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/44817

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Guelph

3. Harner, Nicole. Genetic Improvement of the Pentose-Fermenting Yeast Pachysolen tannophilus for Fermentation of Lignocellulosic Substrates.

Degree: PhD, School of Environmental Sciences, 2015, University of Guelph

URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9153

► An efficient lignocellulosic bioconversion process requires robust inhibitor-tolerant yeast strains capable of fermenting all sugars in non-detoxified lignocellulosic hydrolysates to desired product(s). Pentose-fermenting yeasts such… (more)

▼ An efficient lignocellulosic bioconversion process requires robust inhibitor-tolerant yeast strains capable of fermenting all sugars in non-detoxified lignocellulosic hydrolysates to desired product(s). Pentose-fermenting yeasts such as Pachysolen tannophilus can ferment both glucose and xylose to ethanol, but performs poorly in the presence of hydrolysate inhibitors. We initiated a strain development program to improve the properties of P. tannophilus by non-recombinant means. A blend of random mutagenesis coupled with genome shuffling was used to obtain improved strains of P. tannophilus with enhanced ethanol production and tolerance to inhibitors in hardwood spent sulfite liquor (HW SSL). Genome shuffled strains (GHW301, GHW302 and GHW303) grew at higher concentrations of HW SSL (80 % v/v) compared to HW SSL-tolerant (UHW301, UHW303 and UHW303) UV mutants (60 and 70 % v/v) and the wild-type (WT) strain (50 % v/v). In defined media containing acetic acid (0.70–0.90 % w/v), GHW301, GHW302 and GHW303 exhibited a shorter lag compared to acetic acid-tolerant (UAA301, UAA302 and UAA303) UV mutants, while the WT did not grow. Genome shuffled strains produced more ethanol than the WT at higher concentrations of HW SSL and an aspen hydrolysate. To identify the genetic basis of inhibitor tolerance, whole genome sequencing was carried out on GHW301, GHW302 and GHW303 and compared to the WT strain. Sixty single nucleotide variations were identified that were common to all three genome shuffled strains. Of these, 40 were in gene sequences and 20 were within 5 bp–1 kb either up or downstream of protein encoding genes. Based on the mutated gene products, mutations were grouped into functional categories and affected a variety of cellular functions, demonstrating the complexity of inhibitor tolerance in yeast. Sequence analysis of UV mutants (UAA302 and UHW303) from which GHW301, GHW302 and GHW303 were derived, confirmed the success of our cross-mating based genome shuffling strategy. Whole-genome sequencing analysis allowed identification of potential gene targets for tolerance to inhibitors in lignocellulosic hydrolysates, and this information can guide engineering strategies aimed at developing strains for efficient bioethanol production. Advisors/Committee Members: Hung, Lee (advisor), Trevors, Jack (advisor).

Subjects/Keywords: Acetic acid tolerance; Alcohol; Bioconversion; Bioethanol production; Biofuels; Biomass; Ethanol production; Fermentation; Genome shuffling; Genome sequencing; Inhibitors; Lignocellulose; Pachysolen tannophilus; Pentose-fermenting; Random mutagenesis; Spent sulfite liquor; Strain improvement; Tolerance; Xylose; Yeast

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

APA (6^th Edition):

Harner, N. (2015). Genetic Improvement of the Pentose-Fermenting Yeast Pachysolen tannophilus for Fermentation of Lignocellulosic Substrates. (Doctoral Dissertation). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9153

Chicago Manual of Style (16^th Edition):

Harner, Nicole. “Genetic Improvement of the Pentose-Fermenting Yeast Pachysolen tannophilus for Fermentation of Lignocellulosic Substrates.” 2015. Doctoral Dissertation, University of Guelph. Accessed January 19, 2021. https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9153.

MLA Handbook (7^th Edition):

Harner, Nicole. “Genetic Improvement of the Pentose-Fermenting Yeast Pachysolen tannophilus for Fermentation of Lignocellulosic Substrates.” 2015. Web. 19 Jan 2021.

Vancouver:

Harner N. Genetic Improvement of the Pentose-Fermenting Yeast Pachysolen tannophilus for Fermentation of Lignocellulosic Substrates. [Internet] [Doctoral dissertation]. University of Guelph; 2015. [cited 2021 Jan 19]. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9153.

Council of Science Editors:

Harner N. Genetic Improvement of the Pentose-Fermenting Yeast Pachysolen tannophilus for Fermentation of Lignocellulosic Substrates. [Doctoral Dissertation]. University of Guelph; 2015. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/9153

4. Chagas Junior, Aloísio Freitas. Características agronômicas e ecológicas de rizóbios isolados de solos ácidos e de baixa fertilidade da Amazônia.

Degree: 2007, Universidade Federal do Amazonas

URL: http://tede.ufam.edu.br/handle/tede/3094

►

Para aumentar a contribuição de rizóbia na nutrição e desenvolvimento de plantas é necessário desenvolver pesquisas de seleção de estirpes mais eficientes quanto à fixação… (more)

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Para aumentar a contribuição de rizóbia na nutrição e desenvolvimento de plantas é necessário desenvolver pesquisas de seleção de estirpes mais eficientes quanto à fixação do N2. Este trabalho teve como objetivos, realizar a caracterização morfológica de isolados de rizóbio oriundos de solos amazônicos; avaliar em laboratório, a tolerância à acidez e Al tóxico, a capacidade de solubilização de fosfato de cálcio (P-Ca) e alumínio (P-Al), a produção de acido indol-acético (AIA); a capacidade de isolados em induzirem nodulação e fixarem nitrogênio sob as condições de acidez e baixa fertilidade dos solos regionais em casa-de-vegetação; caracterizar geneticamente os isolados selecionados usando a técnica de PCR-RFLP. Os testes de infectividade mostraram que houve aumento significativo na biomassa de caupi. Quanto à caracterização fenotípica, os 200 isolados mostraram uma grande diversidade. Dentre estes, 165 e 127 isolados apresentaram elevada tolerância nos meios de cultura com pH 4,5 e pH 4,5 + Al, respectivamente. Dos 200 isolados testados, 68 solubilizaram P-Ca e 47 P-Al, sendo que 32 solubilizaram tanto o P Ca quanto o P Al. A produção de AIA aumentou significativamente com as doses de triptofano adicionadas ao meio (p<0,01) para 19 dos 92 isolados testados no experimento. Observou-se produção de matéria seca, número e massa seca dos nódulos e acúmulo de nitrogênio superiores ao tratamento testemunha e similares ao tratamento adubado para vários isolados de rizóbia. Os 20 isolados selecionados e avaliados apresentaram alta diversidade genotípica, onde o dendrograma derivado de perfis de PCR-RFLP mostrou que podem ser divididos dentro de dois gêneros principais, Rhizobium e Bradyrhizobium. Associando-se os resultados de eficiência simbiótica e nodulação, observou-se que os isolados de rizóbio de solos da Amazônia apresentaram bom desempenho e podem ser recomendados para testes de eficiência agronômica em feijão caupi.

To increase the rhizobia contribution to plants nutrition and development is necessary to develop researches for selecting more efficient nitrogen fixation strains. This research work had as objectives, to accomplish morphologic characterization of rhizobia isolated from Amazonian soils; laboratory evaluations about the tolerance to acidity and toxic Al, the capacity to solubilize calcium (P-Ca) and aluminum (P-Al) phosphates, the indole-acetic acid production (AIA); the ability of the isolates to induce nodulation and to fix nitrogen under the acidity and low fertility conditions of the regional soils in greenhouse experiment; to genetically characterize the isolated ones selected using the PCR-RFLP technique. The infectivity test showed that there was significant increase in the cowpea biomass. With relationship to the phenotypic characterization, the 200 isolates showed a great diversity. Among these, 165 and 127 presented high tolerance within the media with pH 4,5 and pH 4,5 + Al, respectively. From the 200 isolates, 68 solubilized P-Ca and 47 P-Al, and 32 isolates solubilized both P-Ca and…

Advisors/Committee Members: Oliveira, Luiz Antonio de, CPF:86260693834, http://lattes.cnpq.br/9931395111001102.

Subjects/Keywords: Tolerância à acidez e Al; Solubilização de fosfato; Ácido indol-acético; Nodulação; Caracterização genética; Ecologia microbiana; Tolerância à acidez e Al; Solubilização de fosfato; Ácido indol-acético; Nodulação; Acidity and Al tolerance; Phosphate solubilization; Indole-acetic acid; Nodulation; Genetic characterization; Microbial ecology; CIÊNCIAS BIOLÓGICAS

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

APA (6^th Edition):

Chagas Junior, A. F. (2007). Características agronômicas e ecológicas de rizóbios isolados de solos ácidos e de baixa fertilidade da Amazônia. (Doctoral Dissertation). Universidade Federal do Amazonas. Retrieved from http://tede.ufam.edu.br/handle/tede/3094

Chicago Manual of Style (16^th Edition):

Chagas Junior, Aloísio Freitas. “Características agronômicas e ecológicas de rizóbios isolados de solos ácidos e de baixa fertilidade da Amazônia.” 2007. Doctoral Dissertation, Universidade Federal do Amazonas. Accessed January 19, 2021. http://tede.ufam.edu.br/handle/tede/3094.

MLA Handbook (7^th Edition):

Chagas Junior, Aloísio Freitas. “Características agronômicas e ecológicas de rizóbios isolados de solos ácidos e de baixa fertilidade da Amazônia.” 2007. Web. 19 Jan 2021.

Vancouver:

Chagas Junior AF. Características agronômicas e ecológicas de rizóbios isolados de solos ácidos e de baixa fertilidade da Amazônia. [Internet] [Doctoral dissertation]. Universidade Federal do Amazonas; 2007. [cited 2021 Jan 19]. Available from: http://tede.ufam.edu.br/handle/tede/3094.

Council of Science Editors:

Chagas Junior AF. Características agronômicas e ecológicas de rizóbios isolados de solos ácidos e de baixa fertilidade da Amazônia. [Doctoral Dissertation]. Universidade Federal do Amazonas; 2007. Available from: http://tede.ufam.edu.br/handle/tede/3094

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