Combining biocatalyzed electrolysis with anaerobic digestion.

Biocatalyzed electrolysis is a microbial fuel cell based technology for the generation of hydrogen gas and other reduced products out of electron donors. Examples of electron donors are acetate and wastewater. An external power supply can support the process and therefore circumvent thermodynamical constraints that normally render the generation of compounds such as hydrogen unlikely. We have investigated the possibility of biocatalyzed electrolysis for the generation of methane. The cathodically produced hydrogen could be converted into methane at a ratio of 0.41 mole methane mole(-1) acetate, at temperatures of 22+/-2 degrees C. The anodic oxidation of acetate was not hampered by ammonium concentrations up to 5 g N L(-1). An overview is given of potential applications for biocatalyzed electrolysis.