Effects of Temperature, Salinity, and pH on Production of Valuable Fatty Acids by Novel Strains of Aurantiochytrium sp.

Abstract

Aurantiochytrium spp. have attracted interest because of their high productivity of polyunsaturated fatty acids, particularly docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and odd-chain fatty acids (OCFAs) such as pentadecanoic acid (PDA) and heptadecanoic acid (HDA). In this study, three novel strains of Aurantiochytrium sp. (9LR, 10W, and 10LW) were cultured at temperatures, salinities, and pH values. All strains grew and produced DHA and EPA at temperatures (10–35°C), salinities (5–80 practical salinity units [PSU]), and initial pH (3–9). The highest biomass, DHA, and EPA production achieved at 25°C, salinity of 20–35 PSU and pH 5–8. The DHA/EPA ratio of strain 9LR was highest at 10°C, whereas pH (p＞0.05) and salinity (p＞0.05) did not significantly affect this ratio. PDA and HDA production by the three strains was optimal at 25°C, 30 PSU, pH 7, while the OCFAs were not produced at 10°C. Our findings emphasize the importance of cultural conditions for Aurantiochytrium sp. growth and fatty acid composition. Because of the tolerance of these strains to wider pH and salinity ranges, various liquid wastes may be used to culture the strains to produce valuable fatty acids, even under extreme conditions.