Breeding high efficient hydrogen producing bacteria by mutagenesis

The fermentative hydrogen bacteria Ethanoligenens sp. ZGX4 was separated from a CSTR reactor, and as an original strain, the bacteria was mutated and bred by UV and nitrous acid combined treatment. A high efficient hydrogen-producing mutant YR-3 with better stability was obtained after continuous passages. When temperature, original pH and glucose concentration were 36±1°C, 6.0 and 12g/L, respectively, the hydrogen-producing capacity (Y_H2) of YR-3 was 3097.65 mL/L-culture, its hydrogen-producing ability increased 70.5% over that the parent strain; The maximal H₂ yield rate Q_H2 was estimated to be 36.6 mmol H₂/g·drycell·h, which was improved 55.1%, the main metabolic end product of mutant YR-3 was ethanol and acetic acid. In each case, YR-3 produced hydrogen at a faster rate and a stronger ability than the wild type, showing a possible potential for commercial hydrogen production and it would also provide useful data for exploring hydrogen-producing mechanism and metabolic pathway of hydrogen-producing bacteria.