Journal article
Assessment of photosynthesis regulation in mixotrophically cultured microalga Chlorella sorokiniana
Algal research (Amsterdam), Vol.19, pp.30-38
11/2016
Handle:
https://hdl.handle.net/2376/117585
Abstract
Mixotrophic growth of microalgae offers great potential as an efficient strategy for biofuel production. In this study, photosynthetic regulation of mixotrophically cultured Chlorella sorokiniana cells was systematically evaluated. Mixotrophic cells in the exponential growth phase showed the highest photosynthetic activity, where maximum photosynthetic O2 evolution was approximately 3- and 4-fold higher than cells in the same phase grown photoautotrophically in 1% CO2 (in air) and air, respectively. Additionally, characteristic chlorophyll fluorescence parameters demonstrated that no limitation in electron transport downstream of PSII was detected in mixotrophic cells. Up-regulation of photosynthetic activity was associated with high total ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylase activity and expression level of phosphoribulokinase (PRK). After 3days, photosynthetic O2 evolution of mixotrophic cells that went to the stationary phase, was strongly reduced, with reduced photochemical efficiency and reorganization of the PSII complex. Simultaneously, enzymatic activity for Rubisco carboxylase and mRNA levels of Rubisco and PRK diminished. Importantly, there was almost no non-photochemical quenching for mixotrophic cells, whether grown in log or stationary phase. A decline in the quantum efficiency of PSII and an oxidized plastoquinone pool (PQ pool) was observed under N-depleted conditions during mixotrophic growth. These results demonstrate that photosynthesis is regulated differently in mixotrophically cultured C. sorokiniana cells than in cells grown under photoautotrophic conditions, with a particularly strong impact by nitrogen levels in the cells.
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Details
- Title
- Assessment of photosynthesis regulation in mixotrophically cultured microalga Chlorella sorokiniana
- Creators
- Tingting Li - Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164-6120, USAHelmut Kirchhoff - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6120, USAMahmoud Gargouri - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6120, USAJie Feng - Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USAAsaph B Cousins - School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USAPhilip T Pienkos - National Renewable Energy Laboratory, Golden, CO 80401, USADavid R Gang - Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6120, USAShulin Chen - Department of Biological Systems Engineering, Washington State University, Pullman, WA 99164-6120, USANational Renewable Energy Lab. (NREL), Golden, CO (United States)
- Publication Details
- Algal research (Amsterdam), Vol.19, pp.30-38
- Publisher
- Elsevier B.V
- Identifiers
- 99900582332201842
- Language
- English
- Resource Type
- Journal article