Hydrogen production in batch culture of mixed bacteria with sucrose under different iron concentrations

The effect of the iron concentration on hydrogen yield was investigated in batch tests by heat-shocked mixed cultures growing on a sucrose mineral medium at 35 °C. The hydrogen production yield increased obviously with increasing iron concentration from 0 to 1600 mg FeSO 4 l - 1 , and then slightly decreased when the iron concentration increased from 1600 to 5000 mg FeSO 4 l - 1 . The maximum amount of hydrogen production (2.73 mol/mol sucrose) was obtained at the iron concentration of 1600 mg FeSO 4 l - 1 . The hydrogen production yield and the butyric acid/acetic acid ratio followed a similar trend, suggesting that the formation of butyrate seems to favor hydrogen production.