The article presents a study by Kato Marcus, C. I. Torres, and B. E. Rittmann on conduction-based modeling of the biofilm anode of a microbial fuel cell. It states that microbial fuel cells can produce an electric current by accumulating the electrons that are produced by the respiration of substrates. The modeling process used by Kato and his companions centered on the biofilm anode that forms an ecosystem and produces electricity.