1. The effects of CO2-induced acidification on Tetraselmis biomass production, photophysiology and antioxidant activity: A comparison using batch and continuous culture
- Author
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Nicolas Lebouvier, Noémie Coulombier, Thierry Jauffrais, Paul Blanchier, Loic Le Dean, Vanille Barthelemy, and Lebouvier, Nicolas
- Subjects
0106 biological sciences ,0301 basic medicine ,Antioxidant ,Photosystem II ,medicine.medical_treatment ,Photobioreactor ,Bioengineering ,Photosynthesis ,7. Clean energy ,01 natural sciences ,Applied Microbiology and Biotechnology ,Lipid peroxidation ,03 medical and health sciences ,chemistry.chemical_compound ,010608 biotechnology ,[CHIM] Chemical Sciences ,Chlorophyll a fluorescence ,medicine ,Food science ,Tetraselmis ,Photosystem II efficiency ,biology ,Chemistry ,Non-photochemical quenching ,Non photochemical quenching ,General Medicine ,biology.organism_classification ,030104 developmental biology ,Phytoplankton ,TBARS assay ,Trolox ,Biotechnology - Abstract
A Tetraselmis sp. was selected for its antioxidant activity owing to its high lipid peroxidation inhibition capacity. With the aim to monitor culture conditions to improve antioxidant activity, effects of CO2-induced acidification on Tetraselmis growth, elemental composition, photosynthetic parameters and antioxidant activity were determined. Two pH values were tested (6.5 and 8.5) in batch and continuous cultures in photobioreactors. Acidification enhanced cell growth under both culture methods. However, the microalgae physiological state was healthier at pH 8.5 than at pH 6.5. Indeed, photosynthetic parameters measured with pulse amplitude modulated (PAM) fluorometry showed a decrease in the photosystem II (PSII) efficiency at pH 6.5 in batch culture. Yet, with the exception of the PSII recovering capacity, photosynthetic parameters were similar in continuous culture at both pH. These results suggest that lowering pH through CO2-induced acidification may induce a lower conversion of light to chemical energy especially when coupled with N-limitation and/or under un-balanced culture conditions. The highest antioxidant activity was measured in continuous culture at pH 6.5 with an IC50 of 3.44 ± 0.6 μg mL−1, which is close to the IC50 of reference compounds (trolox and α-tocopherol). In addition, the principal component analysis revealed a strong link between the antioxidant activity and the culture method, the photophysiological state and the nitrogen cell quota and C:N ratio of Tetraselmis sp.. These results highlight Tetraselmis sp. as a species of interest for natural antioxidant production and the potential of PAM fluorometry to monitor culture for production of biomass with a high antioxidant activity.
- Published
- 2021