Waste biomass is a cheap and relatively abundant source of electrons for microbes capable of producing electrical current outside the cell. Rapidly developing microbial electrochemical technologies, such as microbial fuel cells, are part of a diverse platform of future sustainable energy and chemical production technologies. We review the key advances that will enable the use of exoelectrogenic microorganisms to generate biofuels, hydrogen gas, methane, and other valuable inorganic and organic chemicals. Moreover, we examine the key challenges for implementing these systems and compare them to similar renewable energy technologies. Although commercial development is already underway in several different applications, ranging from wastewater treatment to industrial chemical production, further research is needed regarding efficiency, scalability, system lifetimes, and reliability.
This research was supported by award KUS-I1-003-13 from the King Abdullah University of Science and Technology (B.E.L.) and the Multidisciplinary Research Partnership Ghent Bio-Economy and the European Union Framework Programme 7 project “ProEthanol” (K.R.). The authors also wish to thank T. Lacoere and J. Desloover for assistance in preparing the draft figures and funding from the Commonwealth Scientific and Industrial Research Organization Flagship cluster “Biotechnological solutions to Australia's transport energy and greenhouse gas challenges.”