Аннотация:Photosynthetic hydrogen is an attractive, green and potentially very effective way for the solar fuel production. Green alga Clamydomonas reinhardtii is known to produce H2 in the two stage process based on the S-, N-, or P-deprivation procedures. We have shown that under the S-deprived conditions the amount of Photosystem II, the main electron source for the H2 formation, left during deprivation depends on how quickly the anaerobiosois is created in the culture and directly related to the amount of H2 produced [1]. During the H2 production phase a complex redox reactions at the plastoquinone pool level in the thylakoid membrane are induced by light as was shown by the flash-induced fluorescence decay kinetics measurements (left Figure). It is observed as a fluorescence wave with temporary (within 1 sec) re-reduction of the QA in Photosystem II from the thylakoid membrane components.
We also show that Mg-deprivation, in addition to other known two stage protocols, also results in the prolonged (up to 7 days) H2 formation in C. reinhardtii which is more effective and sustained than the much studied S-deprivation procedure (right Figure). Moreover, Mg-deprivation of the immobilized on the alginate films cells of C. reinardtii show very long (more than 25 days) H2 photoproduction, the longest production reported in green algae so far. Changes in the photosynthetic activity and starch content during Mg-deprivation were similar to ones reported for other deprivation procedures. This indicates the common motif in the metabolic changes leading to H2 producing conditions.