Natural-based chemicals from microalgae such as lipids and pigments are the interests in industries and the bioeconomy. Cold-adapted Ankistrodesmus sp. OR119838, an isolated strain from Cheshmeh-Sabz Lake in northeastern Iran, was cultivated using a two-stage culture strategy under different environmental conditions. With doubling the nitrate concentration at the vegetative stage (170 mg/L) and increasing the light intensity (180 µmol photons/m2/s) the highest specific growth rate (0.61±0.02 per day) and biomass productivity (121.1±7.2 mg/L/day) were observed at 25 ºC. In the optimal growth condition Chl a and Chl b contents of Ankistrodesmus sp. OR119838 reached the highest amount (11.07±0.14 and 11.23±0.29 µg/mL, respectively) at 25 °C. While carotenoid content correlated negatively with optimum biomass productivity (-0.708) and had the best value (12.23±0.29 µg/mL) in nitrogen deficiency (42 mg/L) and intense light conditions (180 µmol photons/m2/s) at 15 °C. Lipid content was increased with declined nitrate concentration (42 mg/L), high light intensity, and 180 µmol photons/m2/s at 25 ºC. The highest percentage of polyunsaturated fatty acids (71.94%) and α-linolenic acid (57.73±6.63%) was observed in conditions with 170 mg/L nitrate concentration and low light intensity (40 µmol photons/m2/ s) at the low temperature (15 ºC). While saturated fatty acids content (43.27%) and palmitic acid reached the highest amount under 40 µmol photons/m2/s, 42 mg/L nitrate at 25 ºC (35.02±5.33 %). Biomass productivity of Ankistrodesmus sp. OR119838, as a cold-adapted strain, decreased by only 8.2% with a 10-degree decline in temperature. Therefore, this strain has good potential to grow in open ponds by tolerating the daily temperature fluctuations.

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