Sustained photobiological hydrogen gas production upon reversible inactivation of oxygen evolution in the green alga Chlamydomonas reinhardtii
Sustained photobiological hydrogen gas production upon reversible inactivation of oxygen evolution in the green alga Chlamydomonas reinhardtii
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DOI：
10.1104/pp.122.1.127
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发表时间：
2000-01-01
期刊：
影响因子：
7.4
通讯作者：
Seibert, M
中科院分区：
文献类型：
--
作者：
Melis, A;Zhang, LP;Seibert, M
该工作描述了一种通过绿藻莱茵衣藻可逆氢化酶途径持续光生物生产H-2气体的新方法。这种单生物、两阶段的H-2生产方法通过暂时将光合作用的O-2进化和碳积累（阶段1）与细胞代谢物的消耗和伴随的H-2生产（阶段2）分离，避免了可逆氢化酶对O-2的严重敏感性。从第1阶段到第2阶段的过渡是由培养物的S剥夺影响的，这可逆地使光系统II （PSII）和O-2进化失活。在这些条件下，细胞在光照下的氧化呼吸使O-2耗竭，并在培养物中引起厌氧，这是诱导可逆氢化酶的必要和充分条件。随后，在光照下观察到持续的细胞H-2气体产生，而在黑暗中没有观察到。H-2产生的机制包括蛋白质消耗和电子从内源性底物传递到叶绿体类囊体中的细胞色素b(6)-f和PSI复合物。氢-2的进化需要PSI的光吸收，这表明铁氧还蛋白的光还原之后是向可逆氢化酶提供电子。后者在叶绿体基质中催化质子还原为H-2分子。
The work describes a novel approach for sustained photobiological production of H-2 gas via the reversible hydrogenase pathway in the green alga Chlamydomonas reinhardtii. This single-organism, two-stage H-2 production method circumvents the severe O-2 sensitivity of the reversible hydrogenase by temporally separating photosynthetic O-2 evolution and carbon accumulation(stage 1) from the consumption of cellular metabolites and concomitant H-2 production (stage 2). A transition from stage 1 to stage 2 was effected upon S deprivation of the culture, which reversibly inactivated photosystem II (PSII) and O-2 evolution. Under these conditions, oxidative respiration by the cells in the light depleted O-2 and caused anaerobiosis in the culture, which was necessary and sufficient for the induction of the reversible hydrogenase. Subsequently, sustained cellular H-2 gas production was observed in the light but not in the dark. The mechanism of H-2 production entailed protein consumption and electron transport from endogenous substrate to the cytochrome b(6)-f and PSI complexes in the chloroplast thylakoids. Light absorption by PSI was required for H-2 evolution, suggesting that photoreduction of ferredoxin is followed by electron donation to the reversible hydrogenase. The latter catalyzes the reduction of protons to molecular H-2 in the chloroplast stroma.