Hydrogen and electrical energy co-generation by a cooperative fermentation system comprising Clostridium and...

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).