Hydrogen Production by Photosynthetic Microorganisms

Abstract

Hydrogen is a clean energy alternative to fossil fuels. We have developed a stable system for the conversion of solar energy into hydrogen using photosynthetic microorganisms. Our system consists of the following three stages: (1) photosynthetic starch accumulation in green algae (400 L × 2); (2) dark anaerobic fermentation of the algal starch biomass to produce hydrogen and organic compounds; and (3) further conversion of the organic compounds to produce hydrogen using photosynthetic bacteria.

We constructed a test plant for this process at Kansai Electric Power Company’s Nankoh power plant in Osaka, and conducted a series of tests using CO₂ obtained from a chemical absorption pilot plant. The photobiological hydrogen production process used a combination of a marine alga, Chlamydomonas sp., and the marine photosynthetic bacterium Rhodovulum sulfidophilum sp. WIS. The dark anaerobic fermentation of algal starch biomass was also investigated.