Photostimulation of H2H2 production in the green alga Chlamydomonas reinhardtii upon photoinhibition of its O2O2-evolving system

A brief exposure (15–30 min) of green alga Chlamydomonas reinhardtii   cells to high-intensity light (2000μmolm-2s-1) was accompanied by rapid suppression of photosynthetic O2O2 evolution. The decline in the rate of O2O2 evolution was followed by stimulation of H2H2 production under light of 15μmolm-2s-1. The effect was dependent on light intensity and cell suspension density. It appears that photoinhibition of photosynthetic O2O2 evolution led to anaerobiosis that is favorable for H2H2 production.