Bioelectrochemical fuel‐cells operated by the cyanobacterium, Anabaena variabilis

Abstract Substantial electric output was delivered from the bioelectrochemical fuel‐cells operated under anaerobic conditions by Anabaena variabilis strain M‐2 and 2‐hydroxy‐1,4‐naphthoquinone. There was a linear relationship between the coulombic output of the fuel‐cells operated in the dark and the glycogen content of the organisms. The coulombic output was increased substantially in the light; the increase was observed even in the absence of CO 2 . Oxygen was evolved by Anabaena cells under the operating conditions of the fuel‐cells. The results demonstrated that the source of electricity obtained from the fuel‐cells is endogenous glycogen in the dark and both glycogen and electrons produced by photosynthetic oxidation of water in the light.