Renewable hydrogen production for fossil fuel processing [electronic resource].
- Oak Ridge, Tenn. : Oak Ridge National Laboratory, 1995.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- pages 187-197 : digital, PDF file
- Additional Creators:
- Oak Ridge National Laboratory
United States. Department of Energy. Office of Scientific and Technical Information
- In the fundamental biological process of photosynthesis, atmospheric carbon dioxide is reduced to carbohydrate using water as the source of electrons with simultaneous evolution of molecular oxygen: H₂O + CO₂ + light → O₂ + (CH₂O). It is well established that two light reactions, Photosystems I and II (PSI and PSII) working in series, are required to perform oxygenic photosynthesis. Experimental data supporting the two-light reaction model are based on the quantum requirement for complete photosynthesis, spectroscopy, and direct biochemical analysis. Some algae also have the capability to evolve molecular hydrogen in a reaction energized by the light reactions of photosynthesis. This process, now known as biophotolysis, can use water as the electron donor and lead to simultaneous evolution of molecular hydrogen and oxygen. In green algae, hydrogen evolution requires prior incubation under anaerobic conditions. Atmospheric oxygen inhibits hydrogen evolution and also represses the synthesis of hydrogenase enzyme. CO₂ fixation competes with proton reduction for electrons relased from the photosystems. Interest in biophotolysis arises from both the questions that it raises concerning photosynthesis and its potential practical application as a process for converting solar energy to a non-carbon-based fuel. Prior data supported the requirement for both Photosystem I and Photosystem II in spanning the energy gap necessary for biophotolysis of water to oxygen and hydrogen. In this paper we report the at PSII alone is capable of driving sustained simultaneous photoevolution of molecular hydrogen and oxygen in an anaerobically adapted PSI-deficient strain of Chlamydomonas reinhardtii, mutant B4, and that CO₂ competes as an electron acceptor.
- Published through SciTech Connect.
Lee, J.W.; Greenbaum, E.; Tevault, C.V.
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