The impact of Fe2+ and Na+ concentrations on hydrogen production with three different fermenter bacteria

Batch experiments were conducted to investigate the effects of Fe2+ and Na+ on the hydrogen (H2) production performance from three different metabolic type hydrogen-producing bacterial strains. The appropriate amount of Fe2+ significantly promoted the H2 production of all three hydrogen-producing bacteria. The combination of H2 production and liquid products showed that Fe2+ was more suitable for the H2 production and metabolism of E. harbinense ZGX4. When the Fe2+ concentration was 0.05 g/L, the H2 production and liquid products concentrations were 2170 mL/L-medium and 6530 mg/L, respectively. Na+ enhanced the H2 production of E. harbinense ZGX4 and C. butyricum 1.209 but inhibited the H2 production of E. cloacae 1.2022. Na+ made C. butyricum 1.209 exhibit the best H2 production and metabolic performance when the Na+ concentration was 2 g/L, while the H2 production, and liquid products concentration were 2460 mL/L-medium and 5350 mg/L, respectively. At the end of the experiment, it was found that the addition of Fe2+ could change the type of fermentation in C. butyricum 1.209. Therefore, further exploration of the effects of other metal ions on model hydrogen-producing strains has great potential for achieving high hydrogen production rates, among other things.