A new review in Discover Electrochemistry examines how bacteria like Geobacter and Shewanella transfer electrons to electrodes, the core process behind microbial fuel cells (MFCs). These systems clean wastewater while generating small amounts of bioelectricity, with minimal chemical additives and low greenhouse gas emissions. The review covers direct electron transfer, mediated electron transfer, microbial nanowires, and the role of biofilm-forming bacteria on anode surfaces. Recent lab work shows promising power density improvements using carbon nanomaterials, iron oxide nanofibers, and engineered microbial consortia. Constructed wetland MFCs have removed nearly 99.8 percent of chemical oxygen demand from tannery wastewater. Still, commercialization faces serious hurdles: high electrode costs, corrosive wastewater, lack of certification standards, and power output too low to compete with conventional generation. The path forward depends on cheaper biomass-derived electrodes, 3D-printed structures, and better separators, not just higher lab-scale power numbers.
