Relationship between oxygen-evolution and hydrogen-evolution in a Chlorococcum strain with high CO2-tolerance

✍ Scribed by J. Schnackenberg; H. Ikemoto; S. Miyachi

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 349 KB
• Volume: 28
• Category: Article
• ISSN: 1011-1344
• DOI: 10.1016/1011-1344(95)07108-e

✦ Synopsis

The relationship between photosynthesis and photohydrogen evolution was investigated in a highly CO2-tolerant strain of Chlorococcum littorale. Concentrations of 0.03% to 40% CO2 were applied during growth of the cells. A concentraction of 5% CO2 is. the most favourable condition for growth, pigment formation and carbohydrate formation, all of which tail off towards a concentration of 40% CO2. The same pattern was observed for oxygen evolution and photohydrogen evolution. The reason for the decline at high CO2 concentrations was found in the partial inhibition of photosystem II (PS II). The initial rates of photohydrogen evolution were at least double those of O2 evolution, demonstrating the higher affinity of the hydrogenase than the NADP-reductase to the electrons provided by the photosynthetic electron transport chain. CO2 concentration had no influence on the in vitro activity of the hydrogenase.