Survey of selected seaweeds for simultaneous photoproduction of hydrogen and oxygen

Journal Article · Mon Feb 28 23:00:00 EST 1983 · J. Phycol.; (United States)

DOI:https://doi.org/10.1111/j.0022-3646.1983.00053.x· OSTI ID:6000015

Greenbaum, E; Ramus, J

Then seaweed species were surveyed for simultaneous photoevolution of hydrogen and oxygen. In an attempt to induce hydrogenase activity (as measured by hydrogen photoproduction) the seaweeds were maintained under anaerobiosis in CO/sub 2/-free seawater for varying lengths of time. Although oxygen evolution was observed in every alga studied, hydrogen evolution was not observed. One conclusion of this research is that, in contrast to the microscopic algae, there is not a single example of a macroscopic alga for which the photoevolution of hydrogen has been observed, in spite of the fact that there are now at least nine macroscopic algal species known for which hydrogenase activity has been reported (either by dark hydrogen evolution or light-activated hydrogen uptake). These results are in conflict with the conventional view that algal hydrogenase can catalyze a multiplicity of reactions, one of which is the photoproduction of molecular hydrogen. Two possible explanations for the lack of hydrogen photoproduction in macroscopic algae are presented. It is postulated that electron acceptors other than carbon dioxide can take up reducing equivalents from Photosystem I to the measurable exclusion of hydrogen photoproduction. Alternatively, the hydrogenase system in macroscopic algae may be primarily a hydrogen-uptake system with respect to light-activated reactions. A simple kinetic argument based on recent measurements of the photosynthetic turnover times of simultaneous light-activated hydrogen and oxygen production is presented that supports the second explanation. 25 references, 3 figures, 1 table.

• Research Organization: Oak Ridge National Lab., TN
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6000015
• Journal Information: J. Phycol.; (United States), Journal Name: J. Phycol.; (United States) Vol. 19:1; ISSN JPYLA
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140505 -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
AQUATIC ORGANISMS
CHEMICAL REACTIONS
ELEMENTS
ENZYME ACTIVITY
ENZYMES
HYDROGEN
HYDROGENASES
NONMETALS
OXIDOREDUCTASES
OXYGEN
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PHOTOSYNTHETIC REACTION CENTERS
PLANTS
SEAWEEDS
SURVEYS
SYNTHESIS