• Fuel cells;
  • biofuel cells;
  • cyanobacterium;
  • electron transport mediator;
  • Synechococcus sp


The current output of the biofuel cells containing a marine alga, Synechococcus sp. and an electron transport mediator, 2-hydroxy-1, 4-naph-thoquinone (HNQ) was increased under illumination and in the presence of CO2. The inhibitory effects of carbonyl cyanide m-chlorophenylhydrazone (CCCP), 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 2,5-dibromomethylisopropyl-p-benzoquinone (DBMIB), phenylmercury acetate (PMA) and N,N′-dicyclohexyl-carbodiimide (DCCD) on the output current of fuel cells run in the light suggested that HNQ accepts electrons mainly at the site of ferredoxin-NADP+ reductase (FNR) in the electron transfer chain. The inhibition of light-induced generation of current output by CCCP indicates that the current is derived from photosynthetic oxidation of water. Endogenous glycogen in algae is required to sustain a steady current output from the fuel cells.