Biological hydrogen production from probiotic wastewater as substrate by selectively enriched anaerobic mixed microflora

Biohydrogen production from probiotic wastewater using mixed anaerobic consortia is reported in this paper. Batch tests are carried out in a 5.0 L batch reactor under constant mesophillic temperature (37 °C). The maximum hydrogen yield 1.8 mol-hydrogen/mol-carbohydrate is obtained at an optimum pH of 5.5 and substrate concentration 5 g/L. The maximum hydrogen production rate is 168 ml/h. The hydrogen content in the biogas is more than 65% and no significant methane is observed throughout the study. In addition to hydrogen, acetate, propionate, butyrate and ethanol are found to be the main by-products in the metabolism of hydrogen fermentation.