Influence of iron on sulfide inhibition in dark biohydrogen fermentation

Sulfide impact on biohydrogen production using dark fermentation of glucose at 37 degrees C was investigated. Dissolved sulfide (S2-) at a low concentration (25 mg/L) increased biohydrogen production by 54% relative to the control (without iron addition). Whereas on initial dissolved S2- concentration of 500 mg/L significantly inhibited the biohydrogen production with total cumulative biohydrogen decreasing by 90% compared to the control (without iron addition). At sulfide concentrations of 500 mg S2-/L, addition of Fe2+ at 3-4 times the theoretical requirement to precipitate 100% of the dissolved S2- entirely eliminated the inhibitory effect of sulfide. (C) 2012 Elsevier Ltd. All rights reserved.