HYDROGEN-PRODUCTION BY PHOTOSYNTHETIC MICROORGANISMS

Hydrogen is a clean energy alternative to the fossil fuels, the main s ource of greenhouse gas emissions. We developed a stable system for th e conversion of solar energy into hydrogen using photosynthetic microo rganisms. Our system consists of the following three stages: 1. Photos ynthetic starch accumulation in green microalgae (400 L x2); 2. Dark a naerobic fermentation of the algal starch biomass to produce hydrogen and organic compounds (155 L x2); and 3. Further conversion of the org anic compounds to produce hydrogen using photosynthetic bacteria (thre e types of reactors, parallel plate, raceway, and tubular). We constru cted a test plant of this process at Nankoh power plant of Kansai Elec tric Power Company in Osaka, Japan, and carried out a series of tests using CO2 obtained from a chemical. absorption pilot-plant. The photob iological hydrogen production process used a combination of a marine a lga, Chlamydomonas sp. MGA 161 and marine photosynthetic bacterium, Rh odopseudomonas sp. W-1S. The dark anaerobic fermentation of algal star ch biomass was also investigated. Sustained and stable starch accumula tion, starch degradation in the algal cell, and hydrogen production fr om algal fermentation and photosynthetic bacteria in the light were de monstrated during several experiments.