Systems biology and adaptive evolution approaches to understanding and increasing power output of microbial fuel cells

FUEL 125

Derek R. Lovley, dlovley@microbio.umass.edu and Kelly P. Nevin, knevin@microbio.umass.edu. Microbiology Department, University of Massachusetts, Morrill Science Center IV, Amherst, MA 01003
Recent studies have demonstrated that the power output of Geobacter- based microbial fuel cells meets or exceeds that of undefined, mixed cultures. These fuel cells have the added advantage that they can be systematically investigated with genome-based technologies. Microarray analysis revealed significant upregulation in fuel cells of genes involved in the production of the electrically conductive pili, known as microbial nanowires, as well as several outer-membrane c-type cytochromes. Genetic studies demonstrated that nanowires and the outer-membrane cytochrome, omcZ, were absolutely required for high-density power production. G. sulfurreducens strains were adapted for faster extracellular electron transfer and to transfer electrons at significantly lower potentials than wild-type cells. Resequencing of the genomes of the adapted strains is providing insights into the mechanisms for this self-optimization for power production. These studies, coupled with genome-based in silico modeling, are aiding in optimizing microbial fuel cell output in a rational rather than an empirical manner.