which transfer excess electrons produced by their central metabolism to the cell surface. “Most bacteria use organic compounds as nutrients, oxidizing the carbon source and generating electrons,” Qian says. “But most of these bacteria are insulators—they generate electrons but do not release them. They are needed in biosynthetic processes to produce biomass. Electrogenic bacteria have developed unique types of transmembrane proteins that deliver unused electrons to the outside, one by one.”
This characteristic makes electrogenic bacteria excellent candidates for use in electricity-generating devices. MFCs use a pair of battery-like terminals (anode and cathode electrodes) connected to an external circuit and an electrolyte solution to conduct electricity. When bacteria physically attach to the anode, electrons generated in the interior of the cell are transferred to an external electrode, producing electrical current