BACKGROUNDCrude glycerol (CG), the major by-product of the biodiesel production process, could be used for biohydrogen production. However, fermentative hydrogen production is limited by the cost of buffer and additional nutrients required for the process. Thus, the purpose of the present study was to determine maximum H-2 production potential of CG in the absence of any additional expensive supplement. Another objective was sustainable utilization of the waste from the H-2 production process. RESULTSA maximum production of 2022.5 mL H-2 L-1 media was achieved by CG bioconversion (without any additional nutrient) and 10 g L-1 CG was found to be optimum. Further, the addition of spent biomass (50 mg L-1) from the process into a subsequent process was found to improve production by 32.5% with a maximum rate of 1040 mL L-1 day(-1). Similarly, nearly 75% of total H-2 was produced at a pH as low as 3.8, indicating high acid tolerance of the strain (Enterobacter aerogenesNRRL B407) used. CONCLUSIONMeat processing and restaurant waste based CG has been characterized and evaluated for maximum H-2 production potential. Utilization of spent biomass from the CG bioconversion process (as supplement) was found to improve process performance. (c) 2013 Society of Chemical Industry