Light acclimation and pH perturbations affect photosynthetic performance in Chlorella mass culture

Aquatic Biology

Irene Malpartida¹  Celia Gil Jerez¹  Rosa M. Rico¹  Cintia Gómez Serrano¹  Moacir A. Torres¹  John Beardall¹  Félix Lopez Figueroa¹  Jacco C. Kromkamp¹  Enrique Navarro¹  Eduardo Peralta¹  João P. Ferreira Ezequil¹  Jose R. Malapascua¹  Robert Abdala¹  Jiří Masojídek¹  Sven Ihnken¹ 

关键词: Chlorella;    Mass culture;    pH perturbance;    Chlorophyll fluorescence;    Oxygen production;    pH drift;    Photosynthesis;    Photoprotection;   

DOI  :  10.3354/ab00586

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Chlorella spp. are robust chlorophyte microalgal species frequently used in mass culture. The pH optimum for growth is close to neutrality; at this pH, theoretically little energy is required to maintain homeostasis. In the present study, we grew Chlorella fusca cells in an open, outdoor, thin-layer cascade photobioreactor (TLC), under ambient photon flux at the theoretically preferred pH (7.2), and let the culture pass the exponential growth phase. Using pH drift experiments, we show that an alkalization to pH 9 supported photosynthesis in the TLC. The increased photosynthetic activity under alkaline conditions was a pH-dependent effect, and not a dissolved inorganic carbon (DIC) concentration- or light intensity-dependent effect. Re-acidification (in one step or in increments) lowered gross oxygen production and increased non-photochemical quenching in short-term experiments. Gross oxygen production and electron transport rates in PSII were uncoupled during the pH perturbation experiments. Electron transport rates were only marginally affected by pH, whereas oxygen production rates decreased with acidification. Alternative electron pathways, electron donation at the plastid terminal oxidase and state-transitions are discussed as a potential explanation. Because cell material from the TLC was not operating at maximal capacity, we propose that alkalization can support photosynthesis in challenged TLC systems.

【 授权许可】

Unknown