The microbiology of microbial electrolysis cells

Electromicrobiology is a new discipline that investigates the ability of microbial species to interact with insoluble external electron acceptors and donors. This ability has most commonly been studied through microbial communities found in association with electrodes as part of a microbial electrolysis cell (MEC). MECs are devices that employ bacteria capable of utilising either an anode as an electron acceptor or a cathode as an electron donor to carry out biologically driven processes. In effect, these devices make use of microbes that are eating and breathing electricity. Potential applications for MECs are ever expanding and currently include bioremediation, biosensing, biofuel production and power generation. MECs that produce overall net power are referred to as microbial fuel cells (MFCs) and have helped to generate much of our initial knowledge regarding electroactive bacteria. Energy consuming MECs have more recently expanded our knowledge on microbial electrosynthesis pathways, whereby microbes reduce CO2 using electrons provided by an electrode. Furthering of our knowledge on electrode-associated microbes has in turn led us to an increased understanding of how microbes in the environment have been developing, powering and utilising their own electricity grids all along. These electrical interactions, between microbes and components of their living and non-living environment, are potentially very important but have been overlooked until very recently.