• Fuel cells;
  • bioelectrochemical fuel cells;
  • cyanobacteria;
  • photosynthetic bacteria


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 CO2. 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.