Hydrogen and electrical energy co-generation by a cooperative fermentation system comprising Clostridium and microbial fuel cell inoculated with port drainage sediment

•Glucose fermentation by Clostridium beijerinckii gives mainly H2 and butyrate.•Native port drainage sediment can be an excellent biocatalyst for a MFC.•Acetate is the preferred substrate for energy generation in the MFC.•Maximum power density lies in the upper values of other reported – 1.25 W/m2.•The system is robust – power density remains constant for a long period. This research work has succeeded in recovering energy from glucose by generating H2 with the aid of a Clostridium beijerinckii strain and obtaining electrical energy from compounds present in the H2 fermentation effluent in a microbial fuel cell (MFC) seeded with native port drainage sediment. In the fermentation step, 49.5% of the initial glucose concentration (56 mmol/L) was used to produce 104 mmol/L H2; 5, 33, 3, and 1 mmol/L acetate, butyrate, lactate, and ethanol also emerged, respectively. MFC tests by feeding the anodic compartment with acetate, butyrate, lactate (individually or as a mixture), or the H2 fermentation effluent provided power density values ranging between 0.6 and 1.2 W/m2. Acetate furnished the highest power density with a nanowire-rich biofilm despite the lowest anode bacterial concentration (1012 16S gene copies/g of sediment). Non-conventional exoelectrogenic microbial communities were observed in the acetate-fed MFC; e.g., Pseudomonadaceae (Pseudomonas) and Clostridia (Acidaminobacter, Fusibacter).