Microbial Fuel Cell

A microbial fuel cell is a bioelectrochemical device that generates electric current from the electrons microorganisms produce as they break down organic matter without oxygen, channeling those electrons from bacteria on an anode through an external circuit to a cathode, where they reduce oxygen or another acceptor. Some designs, called mediated, use a chemical electron mediator to carry the charge, while unmediated designs rely on bacteria that transfer electrons directly through proteins on their own outer membrane, and a proton exchange membrane keeps the charge balanced between the two electrode compartments. The idea dates to 1911, when Michael Cresse Potter first generated current from the yeast Saccharomyces cerevisiae, and in 1931 Barnett Cohen connected microbial half cells in series to produce over 35 volts at a small current; a University of Queensland prototype completed in 2007 converted brewery wastewater into electricity at 10 liter scale, and the technology has since found commercial use treating wastewater as well as powering remote wireless sensors and biosensors that measure water contamination.