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http://arks.princeton.edu/ark:/88435/dsp011r66j451j
Title: | NON-CONVENTIONAL YEAST BIOTECHNOLOGY FOR THE SUSTAINABLE PRODUCTION OF CHEMICALS AND PROTEINS |
Authors: | Hoffman, Shannon Marie |
Advisors: | Avalos, Jose |
Contributors: | Chemical and Biological Engineering Department |
Keywords: | Biofuel Cellulose Dynamic control Optogenetics Pichia pastoris Recombinant protein |
Subjects: | Bioengineering Chemical engineering Molecular biology |
Issue Date: | 2024 |
Publisher: | Princeton, NJ : Princeton University |
Abstract: | To meet targets set by the Paris Agreement, decarbonizing high-emitting industries through sustainable manufacturing is imperative. Engineered microbes offer an attractive option to reduce emissions by producing fuels, chemicals, and proteins more sustainably than from traditional sources like petroleum and livestock. However, despite successes like bioethanol and meat substitutes, economic obstacles hinder wider adoption of these bioprocesses. Overcoming these obstacles requires advancements in both substrate assimilation and strain engineering. While corn starch has been an effective substrate for high-volume products like bioethanol, transitioning to alternatives that do not compete with food supply and pose minimal ecological impacts are needed to expand production. Lignocellulosic biomass is a more sustainable alternative, but slow processing inhibits industrial use. A recently developed emulsions-based pretreatment enhances cellulose breakdown; however, evaluation in yeast fermentations is needed to determine its viability for sustainable manufacturing. In parallel to substrate improvements, expanding the engineering toolbox for species beyond the traditional host Saccharomyces cerevisiae is essential, as the unique strengths of non-conventional yeasts make them naturally superior for many types of products. Of particular interest are the thermotolerant yeasts Ogataea polymorpha and Kluyveromyces marxianus for cellulosic biofuel production, as well as Pichia pastoris, which is a preferred host for protein production due in part to its exceptionally strong methanol-induced PAOX1 promoter. This dissertation describes new substrate and strain technologies to enhance production of diverse products like biofuels, animal proteins, and therapeutics. I first introduce an emulsified simultaneous saccharification and fermentation (eSSF) process that enhances cellulosic biofuel production from conventional and thermotolerant yeasts (Chapter 2). Next, I describe the methodology to dynamically control microbial production of chemicals and proteins with light, which is more versatile and cost-effective than traditional chemical methods (Chapter 3). Building from this foundation, I finally present a light-activated system to control protein production in P. pastoris, which achieves higher yields than PAOX1 without the hazardous and unsustainable need for methanol induction (Chapter 4). Collectively, these advancements contribute new tools that broaden the applications and reduce the practical barriers of sustainable bioprocessing. |
URI: | http://arks.princeton.edu/ark:/88435/dsp011r66j451j |
Type of Material: | Academic dissertations (Ph.D.) |
Language: | en |
Appears in Collections: | Chemical and Biological Engineering |
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