초록
<P><B>Abstract</B></P> <P>Hydrogen (H<SUB>2</SUB>) is considered as the most attractive alternative fuel and photosynthetic-H<SUB>2</SUB> production by green microalgae is regarded as the most promising biofuel. However, incompatibility in the simultaneous O<SUB>2</SUB> and H<SUB>2</SUB> evolution from microalgae prevented the H<SUB>2</SUB> production industry, and the inconvenience of culture medium change for sulfur deprivation treatment also makes it not cost-effective. In this study, a new strategy on regulation of H<SUB>2</SUB> production by a model microalga <I>Chlamydomonas reinhardtii</I> was investigated by using artificial miRNA (amiRNA) technology. A heat-inducible expression vector containing the amiRNA targeting <I>OEE2</I> gene (a photosystem II related protein, oxygen evolving enhancer (OEE2)) was constructed and transformed into <I>C. reinhardtii</I>. With a more rapidly O<SUB>2</SUB> consumption, the transgenic alga showed that <I>OEE</I>2 gene knock down was correlated with the higher H<SUB>2</SUB> production. The highest H<SUB>2</SUB> yield was observed after the second heat shock made to the same transgenic algal culture, about 2-fold more than the control under the same condition. With no need to change medium, our results suggested a prospective way for continuous H<SUB>2</SUB> production by green algae for industry applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>OEE2</I> expression in <I>C. reinhardtii</I> was tightly correlated with sulfur deprivation. </LI> <LI> A heat-inducible expression vector containing amiRNA-OEE2 was constructed. </LI> <LI> Expression of <I>OEE2</I> was conditionally regulated by the amiRNA-OEE2. </LI> <LI> The knock-down effect of amiRNA-OEE2 improved photosynthetic-H<SUB>2</SUB> yield. </LI> <LI> A new strategy on regulation of photo-H<SUB>2</SUB> production was successfully demonstrated. </LI> </UL> </P>