[Effect of bio-electrochemical system on the metabolic changes of Zymomonas mobilis]

A bio-electrochemical system can promote the interaction between microorganism and electrode and consequently change cellular metabolism. To investigate the metabolic performance of Zymomonas mobilis in the bio-electrochemical system, we applied an H-type bio-electrochemical reactor to control Z. mobilis fermentation under 3 V. Compared with the control group without applied voltage, the glycerol in the anode chamber increased by 24%, while the glucose consumption in the cathode chamber increased by 16%, and the ethanol and succinic acid concentration increased by 13% and 8%, respectively. Transcriptomic analysis revealed that the pathways related to organic acid metabolism, redox balance, and electron transfer played roles in metabolic changes. Three significantly differentially expressed genes, ZMO1060 (superoxide dismutase), ZMO0401 (diguanylate cyclase), and ZMO1819 (nitrogen fixation protein), were selected to verify their functions in the bio-electrochemical system. Overexpression of ZMO1060 and ZMO1819 improved the electrochemical activity of Z. mobilis. This study provides insights into the microbial metabolism regulated by the bio-electrochemical system.