Effect of Phytohormone Kinetin on Cell Density, Photosynthetic Pigments, Antioxidant Enzymes, and Fatty Acid Composition of the Microalgae Tetraselmis suecica

Abstract

The effects of phytohormone Kinetin on cell density, photosynthetic pigments, antioxidant enzymes, and fatty acids composition of the microalgae Tetraselmis suecica were investigated. T. suecica was treated with different concentrations (0, 5, 10, 15, 20, and 25 mg/L) of Kinetin at optimal growth conditions (salinity 28 g/L, temperature 25°C, and 24 hr photoperiod). Results indicated an increase in cell density in all treatments compared to the control; however, it was not significant, except for the treatment, 15 mg/L ( $p<0.05$ ). The content of photosynthetic pigments and the activities of catalase and superoxide dismutase, measured after 10 days, significantly increased in the presence of Kinetin ( $p<0.05$ ). Total n-3 fatty acid was significantly higher at 25 mg/L of Kinetin. At 15 mg/L, arachidonic acid (ARA) and eicosapentaenoic acid (EPA) were significantly higher compared to the control ( $p<0.05$ ). Therefore, Kinetin could be useful for the production of the microalgae Tetraselmis suecica to increase growth, chemical composition, and antioxidant enzyme activity.