Bioelectrochemical systems that harvest electricity from wastes, soils, or sediments are designed to operate over long periods of time. However, little is known about the long-term adaptation of electroactive microbes to such non-natural environments. Geobacter sulfurreducens strain KN400 produces the highest current densities and columbic efficiencies of described pure culture electroactive microorganisms. To investigate long-term adaptation to current production, strain KN400 was grown continu