Currently, around 90% of the world's energy is obtained from non-renewable fossil fuels. Microbial fuel cells (MFCs) are a promising new technology that can produce electricity from renewable organic compounds, such as glucose, acetate, and municipal wastewater. MFCs rely on bacteria that extract electrons from organic compounds and use the MFC anode as an electron acceptor, either via direct contact or via biogenic electron shuttles. We studied several potential factors that may affect the MFC dual-chamber performance, including the cathode material and oxidant, the type of microbial growth in the anode compartment, and the type of proton exchange membrane (PEM). For each condition, we measured the MFC performance for a range of resistances from 10 - 10^6 Ohms. We also measured the oxygen diffusion capacity of two types of PEM. We found that biofilms growing on the anode played a greater role in power generation than suspended bacteria, and that Pt-coated cathodes and ferricyanide in the cathode chamber greatly enhanced power generation. The Ultrex PEM allowed less O2 to pass from the cathode to the anode chamber than the Nafion PEM, but Nafion allowed greater power production. Resistors greater than 10,000 Ohms produced unstable conditions. The optimal power production conditions for the MFC were with attached microbial growth in the anode chamber, Pt-coated cathodes, ferricyanide as an oxidant in the cathode chamber, a Nafion PEM, and a 1000-Ohm load.

Keywords: Microbial fuel cell (MFC); Sustainable and renewable fossil fuels; Characterization study