초록
<P><B>Abstract</B></P> <P>Renewable H<SUB>2</SUB> photoproduction by <I>Chlamydomonas reinhardtii</I> offers a desirable bio-system for solar fuels. However, its large-scale application is hindered mainly due to lack of ideal strains. We previously isolated a mutant <I>hpm91</I> which lacks PGR5 and sustains H<SUB>2</SUB> photoproduction for 25 days. To understand the photosynthetic basis for this remarkable phenotype, we hereby investigated its photochemical characteristics during sulfur-deprived H<SUB>2</SUB> photoproduction using <I>in vivo</I> chlorophyll fluorescence spectroscopy. Compared to wild type, effective quantum yield of PSII and PSI of <I>hpm91</I> increased upto 78.9% and 147.6%, respectively. Electron transport rate of each photosystem is closely correlated with the increase of quantum yield, suggesting overall enhanced photochemistry of <I>hpm91</I> under such condition. Moreover, ATP synthase activity decays slower and remains higher in this mutant. These are <I>in vivo</I> evidence demonstrating increased photosynthetic efficiency of <I>hpm91</I> promotes its H<SUB>2</SUB> photoproduction. Together with its competent photoheterotrophic growth in a larger photobioreactor, we propose that <I>hpm91</I> is a valuable strain for re-engineering <I>Chlamydomonas</I> towards improving light energy efficiency in a large-scale system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We evaluate potential of <I>Chlamydomonas</I> mutant <I>hpm91</I> for sustained H<SUB>2</SUB> photoproduction. </LI> <LI> H<SUB>2</SUB>-evolution kinetics, photochemical and ATP synthase activity of <I>hpm91</I> was examined. </LI> <LI> Increased PSI and PSII activity of <I>hpm91</I> promotes its sustained H<SUB>2</SUB> evolution. </LI> </UL> </P>