earticle

영어

Biologically, H2 can be produced through dark fermentation and photo-fermentation. Dark fermentation is fast in H2 production rate and simple in its production process, thus considered to be most promising for commercial application in the near future. However, the yield with most mesophilic bacteria including Escherichia coli is low as >2 mol/mol glucose. The energy recovery for this conversion is only 17.3 %. Also, H2 production activity of most microorganisms is not high enough to meet industrial need. In the present presentation, we report development of various recombinant E. coli to achieve a high H2 production activity and yield on glucose. We also propose that the co-production of ethanol with H2 can be an alternative solution to the low H2 production yield and low energy recovery. The strategy is to re-direct carbon flux to ethanol production at acetyl-CoA node by blocking acetate pathway with improved NADH regeneration rate.We have calculated the theoretical maximum yield for co-production of H2 and ethanol with glucose as substrate. Then, a series of genes in central carbon metabolism have been disrupted to re-direct carbon metabolism and NAD(P)H production in E. coli. A significant improvement in co-production yield has been resulted, although the theoretical maximum has not been reached.