A research team consisting of Akihiro Okamoto (Senior Researcher, Center for Green Research on Energy and Environmental Materials, NIMS), Yoshihide Tokunou (Ph.D. student, Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo; also a recipient of the JSPS Research Fellowship for Young Scientists (DC1)) and Professor Kazuhito Hashimoto (NIMS President, formerly affiliated with the Department of Applied Chemistry, Graduate School of Engineering, University of Tokyo) discovered that “electricity-generating bacteria” used in microbial fuel cells undergo fermentation while producing electricity, which is contrary to the conventional belief that the bacteria only carry out respiration when producing an electric current. The team also identified a mechanism whereby the fermentation process accelerates. Because the fermentation process has greater potential than the respiration process in terms of the bacteria’s contribution to the production of diverse materials, increasing the fermentation efficiency of the bacteria may lead to the development of a novel technology applicable to not only electricity generation but also material production.