Effects of Environmental Factors on the Photosynthesis of Chlorella sp. XQ-20044

Chlorella sp. XQ-20044 is a lipid-rich strain with potential application in microalgal biodiesel. In this study, the effects of light intensity, temperature, pH and salinity on photosynthesis were studied by measuring net photosynthetic O₂ evolution. Suitable light intensities for this Chlorella species ranged from 500 to 1200 μmol·m^-2·s^-1, and saturation light intensity was around 600 μmol·m^-2·s^-1. The appropriate temperatures for photosynthesis were in the range of 30℃ to 42.5℃, with the optimal temperature of 40℃. Suitable pH values ranged from 7.0 to 10.0, and the optimum pH value was 8.0, and salinity concentrations ranged from 0.1-0.3 mol/L, with an optimal salinity of 0.2 mol/L for photosynthesis of this strain. Based on its photosynthetic features, Chlorella sp. XQ-20044 can adapt to strong light intensity, high temperature, high salinity, and slightly alkaline conditions. The adaptation to high salinity is helpful to prevent culture from predator contamination, and is propitious to mass culture of this alga, especially large-scale production with open photo bioreactors. Our results provide a technological basis for the optimization of culture conditions.