Improvement of hydrogen yield of ethanol-producing Escherichia coli recombinants in acidic conditions

Insertion of either hycE or hydA can improve the hydrogen yield with an initial pH of 5.8. The recombinant E. coli with hydA could retain ethanol yield despite high hydrogen production, suggesting that clostridial hydA has an advantage over the hycE gene in hydrogen and ethanol coproduction under acidic conditions. This study could serve as a useful guidance for the future development of an effective strain coproducing hydrogen and ethanol.