Current generation from living microorganisms was first discovered by Potter over 90 years ago 1. This phenomenon is now attracting significant attention from the viewpoint of their potential application to the bacteria based fuel cell. In this fuel cell electricity are generated in the course of bacterial metabolisms using organic pollutants as well as varieties of renewable biomass as a energy resources. Besides the effective utilization of renewable energy, bacterial abilities of self-reproducing and self-renewing offers the long-term fuel cell operation, making this system distinct from the well-developed hydrogen- and methanol- driven fuel cell. Despite above mentioned the great potencies, MFC has not attracted much attention mostly due to its low current density. Furthermore, there are few reports on the mechanisms of interfacial-electron transfer between bacteria and electrodes. Here we report the electron transfer from metal reducing bacteria to the metal and also semiconductor electrodes (graphite, ITO, α-Fe₂O₃, and WO₃). It was confirmed that the metal reducing bacteria can inject the electrons into the conduction band of Fe₂O₃ and WO₃ in the course of metabolisms, but not for TiO₂. This is first observation of direct electron transfer from living bacteria to semiconductor electrodes.

Reference:
[1] M.C.Potter, Proc. Univ. Durham Phil. Soc., 1910,3, 245-249