Abstract
Escherichia coli AFP111 was previously engineered for succinate production by eliminating byproducts of synthesis pathways. Still, the succinate yield is limited due to the insufficient NADH supplement, when fed with glucose. Microbial electrolysis cell (MEC) allows microorganisms to perform unbalanced fermentation by establishing polarized cathode interaction. In this study, a cathode electrode was used as an additional electron donor to improve succinate synthesis by E. coli AFP111. In MEC with -0.65V (vs. Ag/AgCl) poised on cathode electrode, 95.72% electrons were transferred into cells via neutral red (NR), and the ratio of NADH/NAD+ increased by 2.5-fold. Meanwhile, compared with the control experiment, the value of oxidation-reduction potential (ORP) changed from -240 to -265mV in MEC, which was beneficial for NADH generation. During two-stage fermentation (no potential growth stage followed by electric stimulation) in MEC, succinate yield was increased by 29.09% (the final yield was 0.71g g-1 ), and glucose consumption rate was enhanced by 36.22%. In addition, the carbon flux was pumped to succinate and pyruvate metabolism was enhanced. Staged representation of electrochemical stimulated strategy is effective for succinate producing in engineered E. coli by regulating intracellular reducing power, which provides a new concept for producing reduced metabolite in unbalanced fermentation.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call