Photoconversion of Organic Substrates into Hydrogen Using Photosynthetic Bacteria
Under nitrogen-limited conditions, photosynthetic bacteria photoconvert a wide variety of organic substrates nearly totally into H/sub 2/ and CO/sub 2/. More than 98% of the chemical energy of defined organic compounds even from dilute solutions can be recovered as combustible energy of the H/sub 2/ produced. Not calculating the chemical energy input, radiant (solar) energy recoveries are approximately 5% over a wide range of incident light intensities. Batch cultures can photoproduce H/sub 2/ at rates of 175 ml per gram dry weight of cells per hour (equal to a volume of H/sub 2/ per equivalent volume of liquid medium every 4 to 6 hours) when incubated in saturating light. With periodic refeeding, rates remain constant for several weeks. In closed containers H/sub 2/ pressures of 735 psig can be generated. In principle, this pressure can be used to decrease storage volume of the gas, to move it through pipelines or to provide required process pressures. Alcohol stillage and food processing wastes are excellent photoconvertible substances. When non-photosynthetic bacteria synthesizing appropriate polysaccharases are included in co-culture with photosynthetic bacteria, cellulose and other polysaccharides can be converted to H/sub 2/ and CO/sub 2/, albeit at low rates. Prospects for enhancing the photoconversion reactions of photosynthetic bacteria by environmental and genetic manipulations are discussed.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 6552072
- Report Number(s):
- SERI/TP-623-1073
- Resource Relation:
- Conference: 5. annual IGT meeting on energy from biomass and wastes, Lake Buena Vista, FL, USA, 26 Jan 1981
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
09 BIOMASS FUELS
HYDROGEN PRODUCTION
BIOPHOTOLYSIS
ORGANIC WASTES
BIOCONVERSION
ALCOHOLS
BATCH CULTURE
CARBON DIOXIDE
CELLULOSE
LACTIC ACID
ORGANIC ACIDS
PHOTOSYNTHETIC BACTERIA
POLYSACCHARIDES
STOICHIOMETRY
CARBOHYDRATES
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
HYDROXY ACIDS
HYDROXY COMPOUNDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
SACCHARIDES
WASTES
biomass fuels
hydrogen
hydrogen production
biophotolysis
organic wastes
bioconversion
alcohols
batch culture
carbon dioxide
cellulose
lactic acid
organic acids
photosynthetic bacteria
polysaccharides
stoichiometry
carbohydrates
140504* - Solar Energy Conversion- Biomass Production & Conversion- (-1989)
080106 - Hydrogen- Production- Biosynthesis & Photochemical Processes