A photochemical fuel cell system using Anabaena N-7363

A blue-green algae, Anabaena N-7363, was immobilized in 2% agar gel. The hydrogen productivity of the immobilized algae was three times higher than that of free algae. The maximum hydrogen production rate by the immobilized blue-green algae was 0.52 μ moles h^-1 g^-1 (of wet gel) in the medium without nitrogen sources under illumination (10,000 lux). The oxygen evolved was then removed by a reactor containing aerobic bacteria. A photo-current of 15-20 mA was continuously produced for 7 days by the photochemical fuel cell system consisting of the immobilized Anabaena reactor, the oxygen-removing reactor and the hydrogen-oxygen fuel cell. The conversion ratio of hydrogen to current was from 80% to 100%.