Effects of organic and inorganic salts on docosahexaenoic acid (DHA) production by a locally isolated strain of Thraustochytrium sp. T01

Abstract

The traditional source for docosahexaenoic acid (DHA) i.e. fish oil is currently being replaced by microbial sources due to the unpleasant odor and the risk of chemical contamination of fish. Thraustochytrium sp., marine microalgae-like protist is a known source of DHA. In our previous study, we reported a high yielding strain, T01, of Thraustochytrium sp. for DHA production isolated from the mangroves of South India. This strain shows promising yields of biomass and DHA. Shake flask study of T01 yielded 6.17 ± 0.04 gL−1 of DHA. In the present work, we report the effects of organic and inorganic salts on DHA production. Addition of organic salts such as sodium acetate, pyruvate, citrate and malate led to increase in the DHA content in T01 strain. The DHA content increased by 40–46% on addition of sodium salts of organic acids, while inorganic phosphates increased DHA by 33%. The total lipid content also increased (28–33%) with salts of organic acids and 28% with phosphate, but not as much as the increase in DHA. Addition of all the salts together did not show a significant increase in lipid and DHA contents as compared to the addition of individual salts.