Exoelectrogenic bacteria that power microbial fuel cells

The use of microbial fuel cells to generate electrical current is increasingly being seen as a viable source of renewable energy production. In this Progress article, Bruce Logan highlights recent advances in our understanding of the mechanisms used by exoelectrogenic bacteria to generate electrical current and the important factors to consider in microbial fuel cell design. There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells. Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities. Enriched anodic biofilms have generated power densities as high as 6.9 W per m2 (projected anode area), and therefore are approaching theoretical limits. To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell–cell communication.