Outdoor photoacclimation of two Chlorella strains characterized by normal and reduced light-harvesting antennas: photosynthetic activity and chlorophyll-protein organization

0561863 - MBÚ 2023 RIV US eng J - Journal Article
Masojídek, Jiří - Ranglová, Karolína - Bečková, Martina - Torzillo, G. - Knoppová, Jana - Silva Benavides, A. M. - Charvát, Filip - Komenda, Josef
Outdoor photoacclimation of two Chlorella strains characterized by normal and reduced light-harvesting antennas: photosynthetic activity and chlorophyll-protein organization.
Journal of Applied Phycology. Roč. 34, č. 5 (2022), s. 2339-2353. ISSN 0921-8971. E-ISSN 1573-5176
R&D Projects: GA TA ČR(CZ) TN01000048
EU Projects: European Commission(XE) 727874 - SABANA
Institutional support: RVO:61388971
Keywords : Chlorophyll-protein * Chlorophyll fluorescence * Light-harvesting antenna size * Microalgae * Oxygen-production * Photosynthesis
OECD category: Microbiology
Impact factor: 3.3, year: 2022
Method of publishing: Limited access
https://link.springer.com/article/10.1007/s10811-022-02803-1

Photoacclimation of two Chlorella cultures strain g-120 characterised by a reduced size of light-harvesting antenna complex (LHC) and strain R-117 with full antenna size was studied during 5-day outdoor trials. The aim was to correlate the functional and structural changes in the photosynthetic apparatus to culture growth, photochemical activity and thylakoid composition of chlorophyll (Chl)-protein complexes and corresponding polypeptides. Chlorella g-120 was characterized by a low Chl/biomass ratio (< 0.5% of dry weight), about four times lower compared to Chlorella R-117. The important observation was that the high molecular mass Chl-binding protein supercomplexes, i.e. Photosystem II (PSII) and Photosystem I (PSI) cores associated with LHCs were physically missing or negligible in Chlorella g-120. However, there were no visible changes in Chl-protein composition in the g-120 strain during its acclimation to phototrophic conditions. Measurement of the effective absorption cross-section of PSII centres confirmed a markedly reduced functional antenna size in Chlorella g-120 as compared to R-117 which coincided with the absence of the PSII-LHC supercomplexes. We demonstrated that Chlorella g-120 represents a typical reduced antenna-size strain due to its Chl-protein composition. As compared to the full-antenna Chlorella R-117 strain, the outdoor cultures of Chlorella g-120 showed significantly lower oxygen production and electron transport rate measured in-situ. On the contrary, Chlorella g-120 revealed increased futile energy dissipation via non-photochemical quenching and higher respiration compared to Chlorella R-117. Consequently, the potential use of microalgae strains with reduced LHCII for outdoor mass cultivation may not be as straightforward as anticipated from laboratory experiments.
Permanent Link: https://hdl.handle.net/11104/0334388