Influence Of pH, Ammonium and Iron On The Hydrogen Production By Microbial Consortium

Biological hydrogen production processes are known to be friendly and consume less energy compared to hydrogen production through the conventional route, such as thermochemical and electrochemical methods. The aim of this study was to investigate the influence of pH (4 to 7), ammonium sulfate (0.3 to 2 g/L) and iron sulfate (0.1 to 0.5 g/L) concentrations in the dark fermentation for hydrogen production by microbial consortium, using a composite design (2³), on the substrate conversion (mol hydrogen per mol consumed substrate) and hydrogen productivity. Lactose (20 g/L), from milk whey permeate, was used as the carbon source. The fermentation medium was complemented with the following nutrients (g/L): 3 KH₂PO4, 7 K₂HPO₄, 1 MgSO₄, 3 yeast extract and 0.5 meat extract. The findings showed that the culture condition that resulted in higher conversion (6.73 mol H₂/ mol consumed substrate) was obtained to pH of 7, iron sulfate (0.5g/L) and ammonium sulfate (2g/L). In addition, a high level of the hydrogen productivity (73.7 mmolH₂/L.d) was obtained in the same condition.

Acknowledgments: FAPEMIG, CNPq, CAPES and Vale S.A. by financial support.