Effects of metallic ions on hydrogen fermentation in mixed anaerobic culture system

An L27(313) orthogonal test was performed in order to investigate the individual and interactive effects of Fe2+, Zn2+, Ni2+, K+, Mg2+, Mn2+, Fe3+ seven different metallic ions on biohydrogen production in a mixed anaerobic cultures system. The results showed that hydrogen had prominent direct ratio relationship with carbon dioxide and total gas yield while without glucose utilization ratio. By statistics method, the promoting component to hydrogen production was obtained, which consisted of Fe2+ 20 mg/L, Zn2+ 0 mg/L, Ni2+ 1 mg/L, Mg2+ 10 mg/L, K+ 100 mg/L, Fe3+ 100 mg/L, Mn2+ 1 mg/L, whereas it was demonstrated that with the promoting component the hydrogen yield and the total gas yield from PDB medium were raised 42.10% and 8.06%, respectively. It was suggested that FeSO4 prominently enhanced the production of hydrogen contrary to ZnSO4 and the couple of Ni2+-Fe3+ metallic ions was able to activate hydrogenase in the direction of hydrogen production, though optimizing the condition of hydrogen production. Finally, the possible mechanisms underlying the interactive effects of these metallic ions were discussed.