BACKGROUNDFood waste is a valuable source of hydrogen by dark fermentation. Dark fermentation effluent contains volatile fatty acids that can be further converted into more hydrogen using microbial electrolysis cells (MECs). In this process, the anodic potential (E-an) has a significant influence on the MEC performance as well as the effluent composition. The objective of this study was to evaluate the effects of variation of the anode potential and substrate composition (food waste fermentation effluent) on the performance of hydrogen production using two-chamber MECs. RESULTSColonization was conducted using an E-an of 0.5V vs Ag/AgCl. After 38days, the E-an had decreased to 0.3V, resulting in an increase in the hydrogen production rate (from 287 to 482mL H-2 L-cat(-1) d(-1)). A maximum hydrogen production rate of 685mL H-2 L-cat(-1) d(-1) was observed when effluent that contained the highest acetate concentration was utilized. Cathodic hydrogen recovery was higher than 93%, and hydrogen yield was greater than 873mL H-2 g(-1) COD. CONCLUSIONThe start-up strategy in which E-an is decreased after the formation of an electroactive biofilm resulted in increased hydrogen production. The composition of the food waste fermented effluent influences the hydrogen production rate. (c) 2017 Society of Chemical Industry