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Abstract
Acetoin is a versatile chemical used in the cosmetic, food, and fuel industries. High yields and productivities are needed in microbial production to rival chemical synthesis from crude oil. To produce acetoin using Escherichia coli, two enzymes must be introduced from native acetoin producers: acetolactate synthase (alsS gene) and acetolactate decarboxylase (budA gene). Previous studies have demonstrated these two genes and the butanediol dehydrogenase gene from Enterobacter cloacae ssp. dissolvens are effective to produce the reduced form of acetoin, 2,3-butanediol, in E. coli. The first overall objective of this work is to determine genetic modifications that lead to the highest yield of acetoin from glucose by improving the metabolic flux of carbon towards target products. The second overall objective of this work is to utilize nutrient limitation to increase the yield of acetoin from glucose.