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https://hdl.handle.net/2142/121380
Description
Title
Synthetic biology for food applications
Author(s)
Wang, Yirong
Issue Date
2023-07-20
Director of Research (if dissertation) or Advisor (if thesis)
Jin, Yong-Su
Miller, Michael
Committee Member(s)
Cadwallader, Keith
Department of Study
Food Science & Human Nutrition
Discipline
Food Science & Human Nutrition
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Keyword(s)
Heme Overproduction
Xylose
MLF
Abstract
Nowadays, synthetic biology and metabolic engineering have been applied in many industries to produce important bioproducts, such as insulin, artemisinin, and organic acids. However, the application of synthetic biology in the food industry has not been extensively explored. Over the years, despite that the use of synthetic biology for the production of food has led to products like the Impossible Burger and Perfect Day dairy-free ice cream, food companies remain hesitant to utilize synthetic biology technology due to concerns with consumer acceptance to genetically modified foods (GM foods). With the emergence of accurate and precise genome editing techniques, such as CRISPR-Cas, both consumers and manufacturers can benefit from synthetic biology with minimal risks. Therefore, we believe that now is the time for a new revolution in food industry where novel genome editing technology replaces traditional genetic engineering in food production to produce food and food ingredients with higher quality, better flavor, improved safety, and lower environment impacts.
The overall goal of this thesis study is to explore the potential of synthetic biology for food applications, especially using yeast Saccharomyces cerevisiae. Firstly, we reviewed current literature discussing synthetic biology for food applications. Then, we demonstrated the feasibility to improve red wine flavor through integrating a malolactic pathway in the genome of wine yeast using scarless Cas9-based genome editing. Subsequently, we overproduced the heme molecule in S. cerevisiae using xylose as a carbon source, whose biomass can be used to produce yeast extract with high heme content. The heme-enriched yeast extract can be added to meat alternatives as a flavoring agent.
In conclusion, our engineered wine yeast strains demonstrated the capability of L-malate conversion into lactic acid, while the malate consumption was not sufficient to complete malolactic fermentation in wine. The catalytic activity of malolactic enzyme MLEA might be limiting and to be further improved. Our heme-overproducing strains indicated that our rational design to hyperaccumulate heme in engineered yeast was working as expected but we observed growth defects in highly engineered yeast strains. YW5, containing rox1 deletion, vps10 deletion, HEM3 overexpression, and LegH expression, performed best but exhibited severe growth defect under xylose condition. One possible approach to further improve the titer of heme in YW5 is to employ adaptive laboratory evolution under xylose conditions.
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