Sulfate-reducing bacteria (SRB) have an extremely high hydrogenase activity and in natural habitats where sulfate is limited, produce hydrogen fermentatively. However, the production of hydrogen by these microorganisms has been poorly explored. In this study we investigated the potential of SRB for H-2 production using the model organism Desulfovibrio vulgaris Hildenborough. Among the three substrates tested (lactate, formate and ethanol), the highest H-2 production was observed from formate, with 320 mL L-medium(-1) of H-2 being produced, while 21 and 5 mL L-medium(-1) were produced from lactate and ethanol, respectively. By optimizing reaction conditions such as initial pH, metal cofactors, substrate concentration and cell load, a production of 560 mL L-medium(-1) of H-2 was obtained in an anaerobic stirred tank reactor (ASTR). In addition, a high specific hydrogen production rate (4.2 L g(dcw)(-1) d(-1); 7 mmol g(dcw)(-1) h(-1)) and 100% efficiency of substrate conversion were achieved. These results demonstrate for the first time the potential of sulfate reducing bacteria for H2 production from formate. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.