Photobiotechnology: Algal hydrogen production and photoconductivity of metalized chloroplasts
Sustained hydrogen photoevolution from Chlamydomonas reinhardtii and C. moewusii was measured under an anoxic, CO{sub 2}-containing atmosphere. It has been discovered that light intensity and temperature influence the partitioning of reductant between the hydrogen photoevolution pathway and the Calvin cycle. Under low incident light intensity (1-3 W m{sup {minus}2}) or low temperature (approx. O{degrees}C), the flow of photosynthetic reductant to the Calvin cycle was reduced, and reductant was partitioned to the hydrogen pathway as evidenced by sustained H{sub 2} photoevolution. Under saturating light (25 W m{sup {minus}2}) and moderate temperature 20 {plus minus} 5{degrees}C, the Calvin cycle became the absolute sink for reductant with the exception of a burst of H{sub 2} occurring at light on. A novel photobiophysical phenomenon was observed in isolated spinach chloroplasts that were metalized by precipitating colloidal platinum onto the surface of the thylakoid membranes. A two-point irradiation and detection system was constructed in which a continuous beam helium-neon laser ({lambda} = 632.8 nm) was used to irradiate the platinized chloroplasts at varying perpendicular distances from a single linear platinum electrode in pressure contact with the platinized chloroplasts. No external voltage bias was applied to the system. The key objective of the experiments reported in this report was to measure the relative photoconductivity of the chloroplast-metal composite matrix. 46 refs., 1 tab.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- USDOD; USDOE; Department of Defense, Washington, DC (USA); USDOE, Washington, DC (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5783092
- Report Number(s):
- CONF-9106192-1; ON: DE91013232
- Resource Relation:
- Conference: International symposium on new biomaterials and global ecology, Tokyo (Japan), 25-27 Jun 1991
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
14 SOLAR ENERGY
59 BASIC BIOLOGICAL SCIENCES
BIOPHOTOLYSIS
TEMPERATURE DEPENDENCE
CHLAMYDOMONAS
HYDROGEN PRODUCTION
COMPOSITE MATERIALS
PHOTOCONDUCTIVITY
PLATINUM
COLLOIDS
CHLOROPLASTS
HYDROGENASES
PHOTOSYNTHETIC MEMBRANES
ALGAE
BIOCONVERSION
CELL CONSTITUENTS
CHEMICAL REACTIONS
CHLOROPHYCOTA
DECOMPOSITION
DISPERSIONS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
ENZYMES
MATERIALS
MEMBRANES
METALS
MICROORGANISMS
OXIDOREDUCTASES
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PHYSICAL PROPERTIES
PLANTS
PLATINUM METALS
TRANSITION ELEMENTS
UNICELLULAR ALGAE
080106* - Hydrogen- Production- Biosynthesis & Photochemical Processes
140505 - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
550700 - Microbiology