H2 production by a large phototrophic bacterium isolated from the bacterial plate of Lake Kaiike.

A large-celled phototrophic bacterium, which densely populates the O2-H2S interface of Lake Kaiike (Kamikoshiki Island), vigorously produced H2 during the growth. The H2 production was intimately associated with photosynthesis. In situ H2 production and N2 fixation at the bacterial plate (November 1986) were quite low. But when the same sample was incubated after supply with neutralized Na2S 9H2O solution under the light, it showed elevated rates of both processes.