Photosynthetic hydrogen production

Among various technologies for hydrogen production, the use of oxygenic natural photosynthesis has a great potential as can use clean and cheap sources water and solar energy. In oxygenic photosynthetic microorganisms electrons and protons produced from water and redirected by the photosynthetic electron-transport chain via ferredoxin to the hydrogen-producing enzymes hydrogenase or nitrogenase. By these enzymes, e(-) and H+ recombine and form molecular hydrogen. Hydrogenase activity can be very high but is extremely sensitive to the photosynthetically evolved O-2 that leads to reduced and unstable H-2 production. However, presently, several approaches are developed to improve the energetic efficiency to generate H-2. This review examines the main available pathways to improve the photosynthetic H-2 production. (C) 2010 Elsevier B.V. All rights reserved.