Effect of metal ions on dark fermentative biohydrogen production using suspended and immobilized cells of mixed bacteria

Abstract

The effect of Fe2+, Mg2+, Ca2+, and Ni2+ ions on dark fermentative biohydrogen production was evaluated using suspended and immobilized cells of anaerobic mixed bacteria at different concentrations of 0, 50, 100, 300, 500, and 1,000 mg/L in batch operation. A maximum biohydrogen fraction of 45.21%, which corresponded to a biohydrogen yield of 292.8 mL H2/g total volatile solids, was obtained in batch process using Fe2+ (1,000 mg/L) and immobilized cells. Furthermore, a chemical oxygen demand removal efficiency of 52.30% was also achieved in this fermentation process.