Improved hydrogen photoproduction from photosynthetic bacteria and green algae
Photosynthetic bacteria evolve hydrogen at much higher rates than do other classes of photosynthetic microorganisms. In addition, they tolerate harsh environments, grow rapidly, and utilize both visible and near infrared light in photosynthesis. They do not split water, but this does not necessarily eliminate their potential use in future applied systems. They are easily manipulated genetically, and thus might be modified to metabolize common biomass waste materials in place of expensive defined organic substrates. Furthermore, the potential for increasing hydrogen photoproduction via genetic techniques is promising. Strains that partially degrade cellulose, have high photoproduction rates, or contain very large amounts of the enzymes associated with hydrogen metabolism have been isolated. Green algae also produce hydrogen but are capable of using water as a substrate. For example, C. reinhardi can evolve hydrogen and oxygen at a molar ratio approaching 2:1. Based upon effect of dichlorophenyl dimethylurea (a specific inhibitor of photosystem II, PSII) on hydrogen photoproduction in the wild type strain and upon results obtained with PSII mutants, one can demonstrate that water is the major source of electrons for hydrogen production. The potential efficiency of in vivo coupling between hydrogenase and the photosynthetic electron transport system is high. Up to 76% of the reductants generated by the electron transport system can be channeled directly to the enzyme for in vivo hydrogen production. Rates exceeding 170 ..mu..moles of H/sub 2/ mg Chl/sup -1/ hr/sup -1/ have been observed.
- Research Organization:
- Solar Energy Research Inst., Golden, CO (USA)
- DOE Contract Number:
- EG-77-C-01-4042
- OSTI ID:
- 5818816
- Report Number(s):
- SERI/TP-33-409
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
080106* -- Hydrogen-- Production-- Biosynthesis & Photochemical Processes
14 SOLAR ENERGY
140505 -- Solar Energy Conversion-- Photochemical
Photobiological
& Thermochemical Conversion-- (1980-)
ALGAE
AQUATIC SPECIES PROGRAM
BACTERIA
BIOCONVERSION
BIOPHOTOLYSIS
CHEMICAL REACTIONS
CHLAMYDOMONAS
CONVERSION
DECOMPOSITION
ENERGY CONVERSION
ENZYMES
GREEN ALGAE
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN PRODUCTION
HYDROGENASE
MICROORGANISMS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PHOTOSYNTHETIC BACTERIA
PLANTS
RHODOPSEUDOMONAS
SOLAR ENERGY CONVERSION
UNICELLULAR ALGAE
WATER