The effects of CO2-induced acidification on Tetraselmis biomass production, photophysiology and antioxidant activity: A comparison using batch and continuous culture

A Tetraselmis sp. was selected for its antioxidant activity owing to high lipid peroxidation inhibition capacity. With the aim monitor culture conditions improve activity, effects of CO2-induced acidification on growth, elemental composition, photosynthetic parameters and were determined. Two pH values tested (6.5 8.5) in batch continuous cultures photobioreactors. Acidification enhanced cell growth under both methods. However, microalgae physiological state healthier at 8.5 than 6.5. Indeed, measured with pulse amplitude modulated (PAM) fluorometry showed a decrease photosystem II (PSII) efficiency 6.5 culture. Yet, exception PSII recovering capacity, similar pH. These results suggest that lowering through may induce lower conversion light chemical energy especially when coupled N-limitation and/or un-balanced conditions. The highest an IC50 3.44 ± 0.6 ?g mL?1, which is close reference compounds (trolox ?-tocopherol). In addition, principal component analysis revealed strong link between method, photophysiological nitrogen quota C:N ratio sp.. highlight as species interest natural production potential PAM biomass activity.