Biocatalyst and engineering optimization of anode to develop high power density microbial fuel cells

Microbial fuel cells (MFCs) are an upcoming green technology to convert waste and renewable materials into electricity. This paper reports development of high power density MFCs via biocatalyst and engineering optimization. Biocatalyst optimization was conducted by targeting enrichment of electrogenic biofilm-forming organisms capable of electron transfer in the absence of mediators. Microbial consortia were enriched using a various carbon sources including sugars, organic acids as well as other wastewater components. A single-chamber MFC with a flow-through anode and an air-only cathode was used to enrich the organisms. Engineering optimization parameters included electrode spacing, substrate delivery and flow pattern in the anode chamber. Power density was compared between a Pt-based cathode as well as an aqueous ferricyanide cathode. The potential of the anode biocatalyst to support power densities up to 300 W/m3 (3200 mW/m2) was demonstrated. Individual internal resistances below 5 ohms were obtained for the anode using electrochemical impedance spectroscopy. Long-term stability of the MFCs as well as application to various industries including the biofuels and bioproducts industry will be discussed.