Maximizing photosynthetic productivity and solar conversion efficiency in microalgae by minimizing the light-harvesting chlorophyll antenna size of the photosystems

Technical Report · Sat Aug 01 04:00:00 EDT 1998

DOI:https://doi.org/10.2172/305596· OSTI ID:305596

Melis, A.; Neidhardt, J.; Benemann, J. R. ^[1]

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1. Univ. of California, Berkeley, CA (United States). Dept. of Plant and Microbial Biology

The solar conversion efficiency and productivity of photosynthesis in light-acclimated Dunaliella salina (green algae) were analyzed. Cells were grown under continuous low-light (LL; 100 {micro}mol photons/m{sup 2} s) or high-light (HL; 2,000 {micro}mol photons/m{sup 2} s) conditions. HL-grown cells exhibited signs of chronic photoinhibition, i.e., a lower pigment content, a highly truncated chlorophyll (Chl) antenna size for the photosystems, and accumulation of photodamaged photosystem-II (PSII) reaction centers in the chloroplast thylakoids. In spite of these deficiencies, high-light-grown cells showed photosynthetic productivity (300 mmol O{sub 2}/(mol Chl) s) that was {approximately} 3 times greater than that of the normally pigmented LL-grown cells ({approximately} 100 mmol O{sub 2}/(mol Chl) s). Recovery from photoinhibition in the HL-grown cells, induced in the absence of a light-harvesting Chl antenna size enlargement, increased photosynthetic productivity further to {approximately} 650 mmol O{sub 2}/(mol Chl) s. It is shown that, under moderate to high light conditions, D. salina with a highly truncated Chl antenna size will display superior photosynthetic productivity, solar conversion efficiency and H{sub 2} production when compared to the normally pigmented control cells. Estimates of H{sub 2} production in mass culture suggest an average of 200 L H{sub 2}/m{sup 2} d for the cells with the truncated Chl antenna, and less than 50 L H{sub 2}/m{sup 2} d for the normally pigmented cells.

• Research Organization: National Renewable Energy Lab., Golden, CO (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FC36-98GO10278
• OSTI ID: 305596
• Report Number(s): NREL/CP--570-25315-Vol.1; CONF-980440--Vol.1; ON: DE98007507
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
14 SOLAR ENERGY
BIOPHOTOLYSIS
CHLOROPHYLL
EXPERIMENTAL DATA
HYDROGEN PRODUCTION
PHOTOSYNTHESIS
PRODUCTIVITY
UNICELLULAR ALGAE