초록
Hydrogenase is one of the vital rate-limiting enzymes in biohydrogen production metabolism. The activity of hydrogenase impacts the speed of hydrogen production. In the present study, the novel high efficient H<SUB>2</SUB>-producing bacterium Ethanoligenens harbinense YUAN-3 was selected for characterization of the relationship between hydrogenase activity and its hydrogen production performance. The effects of the ecological factors of temperature, pH, C/N ratio Mg<SUP>2+</SUP>, and Fe<SUP>2+</SUP> concentration on hydrogen production and the activity of hydrogenase were investigated. The activity of hydrogenase decreased quickly after reaching a maximum rate of 2.18 molH<SUB>2</SUB> molGlucose<SUP>-1</SUP> (H<SUB>2</SUB> yield of 1942.5 mL L<SUP>-1</SUP>) along with the fermentation process. The highest hydrogenase activity of strain E. harbinense YUAN-3 was optimized under conditions of 35 <SUP>o</SUP>C, pH 4.5, and the optimal C/N ratio of 22.4. It was also found that the optimal concentration of 300 mg L<SUP>-1</SUP> MgCl<SUB>2</SUB>.6H<SUB>2</SUB>O and 300 mg L<SUP>-1</SUP> FeSO<SUB>4</SUB>.7H<SUB>2</SUB>O were playing key roles in hydrogen production. The highest hydrogen production was improved to 2.62 molH<SUB>2</SUB> molGlucose<SUP>-1</SUP> (H<SUB>2</SUB> yield of 2138.5 mL L<SUP>-1</SUP>) with the maximum activity of the hydrogenase 0.352 U mg<SUP>-1</SUP> protein.