Search

Previously, we found that marine Chlorella pyrenoidosa strain IOAC707S could generate hydrogen (H 2 ) under nitrogen deprivation in seawater medium, without dark incubation, N 2 flushing or addition of protonophore. In this work, the H 2 yield of C. pyrenoidosa was enhanced, and the mechanism of H 2 photoproduction was investigated. It was found that C. pyrenoidosa could produce H 2 under hypoxic conditions, which indicated the hydrogenase of C.pyrenoidosa could tolerate a low concentration of O 2 . Nitrogen deprivation could lower the efficiency of photosyntem (PS) II photochemical activity and PSII oxygenic activities, which were favorable for rapid establishment of anoxia and efficient H 2 photoproduction, and thus significantly enhance H 2 photoproduction of C. pyrenoidosa . Pre-culture in nitrogen-deprived medium could further increase the H 2 yield of C. pyrenoidosa , for its more severe inhibition of the oxygen-evolving complex, electron transport and photochemical efficiency of PSII, and PSII oxygenic activities, which facilitated the establishment of anaerobiosis and activation of hydrogenase. [ABSTRACT FROM AUTHOR]