Electromicrobiology: An Emerging Reality—A Review

Electromicrobiology is the study of the interactions between the novel electrical properties of microorganisms and electronic devices. A diversity of microorganisms such as Geobacter and Shewanella species is capable of interacting electrically with the environment. Many recent advances in Electromicrobiology stem from studying Microbial Fuel Cells (MFCs) which are a device designed for the harvesting of electric current from organic compounds. Three types of Microbial Fuel Cells are known which are heterotrophic microbial fuel cells, photosynthetic microbial fuel cells (bio-solar cells) designed to harness the most abundant and promising energy source (solar irradiation) of earth and the hybrid microbial fuel cell. Electric microorganisms especially Sporomusa ovata can use electron derived from electrodes to reduce carbondioxide to multicarbon extracellular organic compounds in a process known as Microbial Electrosynthesis. The mechanism of electron transfer to electrodes by electric microbes is either by the use of electron shuttling molecules, redox-active proteins or via conductive pili. Conductive microorganisms and/or their nanowires have a number of potential practical applications but additional basic research will be necessary for rational applications. This review looks at the Microbial Fuel Cells, the associated mechanisms and applications.