Based on a genome-scale metabolic model of Escherichia coli, we identified five different genetic strategies for producing pyruvate, a precursor to different biofuels and chemicals, at high yield. The knockout targets affect acetyl-CoA production, fermentation products (acetate and lactate) and NADH or NADPH formation. A number of mutant strains have been constructed and six of them achieved yields of more than 0.88 g pyruvate per g of glucose (90% theoretical yield) in aerobic condition. Pyruvate is a precursor for synthesizing ethanol. Using an expression cassette containing pyruvate decarboxylase (Pdc) and alcohol dehydrogenase II (AdhB) from Zymomonas mobilis, we were able to alter the engineered pyruvate strains to produce ethanol. Since pyruvate is a starting compound for synthesizing various valuable metabolites we developed a computational algorithm to identify what non-native metabolites could be made from pyruvate and which enzymes need to be added into E. coli to enable their production. The developed high yield pyruvate producing strains can subsequently serve as a starting platform for developing strains to produce other important chemicals.

Metabolic engineering of<i> Escherichia coli</i> for production of ethanol based on in silico-designed pyruvate producing strains

247th National Meeting (2014)

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Metabolic engineering of Escherichia coli for production of ethanol based on in silico-designed pyruvate producing strains