Screen of O2-tolerate Phenotype of Klebsiella oxytoca HP1 Mutants with High H2-evolving Activity by Selection with MNZ Combination O2

Abstract:

Hydrogenases are key enzyme for bio-hydrogen production, most of them were rapidly inactivated by oxygen. It is important to bio-hydrogen production and hydrogen application that improve the O2-tolerance of hydrogenase. In this experiment, the hydrogen producing strain Klebsiella oxytoca HP1 was treated with 1% ethyl methanesulfonate(EMS) , the mutants with high O2-toleration ability were screened with 40mmol/L metronidazole (MNZ) and 21% oxygen. The H2-evolving activity of the first generation mutant HP1-A15 was increased 3.70 times than that of the wild-type (WT) under 15% oxygen. The H2-evolving activity of the second generation mutant HPA15-37 was enhanced 11 times than that of WT under the condition of 21% oxygen. The mutants HP1-A15 and HPA15-37 had steady heredity. These results suggest that MNZ and in addition oxygen is a good way to screen of O2-tolerate phenotype of facultativeanaerobe with high H2-evolving activity.