Synergistic Effect of Light and Temperature on Growth and Biochemical Composition of Chlorella sorokiniana Cultures

This study investigated the combined effects of light intensity and temperature on the growth and biochemical composition of Chlorella sorokiniana (Chlorophyceae) under controlled laboratory conditions. The cultures were exposed to two continuous photon flux densities (100 and 200 µmol m−2 s−1) and six different temperatures (20, 25, 30, 35, 40, 45 °C). At a light intensity of 100 µmol m−2 s−1, the highest attained volumetric productivity was 16.92 mg DW L−1 h−1 at 25 °C, resulting in a mean final biomass density of 3.25 g DW L−1 after 8 days of cultivation. In contrast, at 200 µmol m−2 s−1, there were notable differences in growth performance, with maximum biomass volumetric productivity reaching 31.4 mg DW L−1 h−1 at 30 °C and a final biomass density of 6.08 g DW L−1. The optimal temperature for growth depended strongly on light intensity. Cultures at 20 °C thrived at 100 µmol m−2 s−1 but showed negligible growth at 200 µmol m−2 s−1. No growth occurred at 45 °C under either light intensity. Furthermore, temperature significantly affected biomass composition, affecting both fatty acid and amino acid profiles. These findings provide valuable insights for optimizing the cultivation of C. sorokiniana outdoors.