Effect of carbon limitation on photosynthetic electron transport in Nannochloropsis oculata

Journal of Photochemistry and Photobiology. B, Biology
Tomáš ZavřelPeter J Ralph

Abstract

This study describes the impacts of inorganic carbon limitation on the photosynthetic efficiency and operation of photosynthetic electron transport pathways in the biofuel-candidate microalga Nannochloropsis oculata. Using a combination of highly-controlled cultivation setup (photobioreactor), variable chlorophyll a fluorescence and transient spectroscopy methods (electrochromic shift (ECS) and P700redox kinetics), we showed that net photosynthesis and effective quantum yield of Photosystem II (PSII) decreased in N. oculata under carbon limitation. This was accompanied by a transient increase in total proton motive force and energy-dependent non-photochemical quenching as well as slightly elevated respiration. On the other hand, under carbon limitation the rapid increase in proton motive force (PMF, estimated from the total ECS signal) was also accompanied by reduced conductivity of ATP synthase to protons (estimated from the rate of ECS decay in dark after actinic illumination). This indicates that the slow operation of ATP synthase results in the transient build-up of PMF, which leads to the activation of fast energy dissipation mechanisms such as energy-dependent non-photochemical quenching. N. oculata also increased content...Continue Reading

Citations

Jun 4, 2020·Biotechnology for Biofuels·Jessica Varela VillarrealChristine Rösch
Aug 14, 2020·The Science of the Total Environment·Hao HuRaymond Jianxiong Zeng

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