Fermentation approach for enhancing 1-butanol productionusing engineered butanologenic Escherichia coli

Abstract

In this study, engineered butanologenic Escherichia coli T5 constructed by the OGAB method was used for1-butanol production. The results showed the feasibility of the artificial butanologenic operon, (PromoterPr)-thil-crt-bcd-etfB-etfA-hbd-adhe1-adhe, where the 1-butanol titer, specific BuOH yield, and BuOH yieldwere 4.50 mg/L, 4.50 mg-BuOH/g cell, and 0.35 mg-BuOH/g-glucose, respectively. Fermentation conditionsof anaerobic, low initial concentrations of carbon sources, low oxidation state of carbon source,pH of 6, addition of glutathione and citrate, had been shown for efficiently improving the 1-butanol production.The premise behind these fermentation approaches can be categorized into two lines of reasoning,either elevated the availability of acetyl-CoA or lowered the intracellular redox state. By comparingthe fermentation conditions tested in this study, pH has been shown to be the most efficiency strategiesfor 1-butanol production while the replacement of glucose with glycerol provides the highest improvementin butanol yield