Photosynthetic bioelectrochemical cell utilizing cyanobacteria and water-generating oxidase

A novel photosynthetic bioelectrochemical cell that utilizes biocatalysts i n both anode and cathode compartments was constructed for the first time, i n the anodic half-cell, some parts of the electrons produced by the oxidati on of water in the photosystem of cyanobacteria are transferred to the carb on felt anode through quinonoid electron transfer mediators. The electron i s passed to dioxygen to regenerate water in the cathodic half-cell reaction with an aid of bilirubin oxidase reaction via a mediator. The maximum elec tric power was about 0.3-0.4 W m(-2) for the projective electrode surface a rea at an apparent efficiency of the light energy conversion of 2-2.5%. The factors governing the cell output are discussed on the basis of the potent ial-current curves of each half-cell. (C) 2001 Elsevier Science Inc. All ri ghts reserved.