Microbial Fuel Cells: Plug-in and Power-on Microbiology

I f scientists have their way, “green” beer won’t be limited to St. Patrick’s Day celebrations anymore. Breweries are taking their wastewater, which is rich in organic material, and turning it into electricity with bacteria in microbial fuel cells (MFCs). MFCs can generate valuable commodities from a variety of organic wastes that are abundant and essentially free—bacteria have generated electricity from industrial wastewaters, sewage, and even sediment. In MFCs, bacteria act as living catalysts to convert organic substrates into electricity. While this technology may sound like an answer to our energy crisis, MFCs are not yet viable for most applications. Ongoing research is dedicated to optimizing their performance, with only recent attention being given to the microbial details of waste-towattage conversion. MFCs may well have a place in the future energy paradigm, as well as in bioremediation and industrial-chemical and hydrogen production. For MFCs to be considered more than a lab novelty, standardization of data expression is necessary to allow reliable and accurate comparison of results. Advances in the hardware, operation, and microbial components are also needed. However, MFCs are valuable research tools for characterizing the physiology and ecology of extracellular electron transfer, modeling electron flow in complex microbial ecosystems, and framing and testing ecology theory.