Production of squalene and fatty acids byThraustochytrium sp. RT2316-16: Effects of dissolved oxygen and the medium composition

The psychrophilic marine microbe Thraustochytrium sp. RT2316-16 produced carotenoids, lipids containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and the triterpenoid squalene. The composition of the culture medium and the dissolved oxygen (DO) concentration affected both the squalene content of the biomass and the composition of the fatty acids. Accumulation of total lipids and squalene in the biomass was favored if a high mass ratio of glucose (or glycerol) relative to organic nitrogen was combined with a DO concentration of 20% of air saturation. The highest concentration of squalene in the medium containing glucose was 1485 ± 63 mg L ^–1 , whereas it was 906 ± 45 mg L ^–1 in the medium containing glycerol. Relatively high concentrations of EPA and DHA were obtained under conditions that promoted the growth of the lipid-free biomass in a medium with glucose. A fed-batch operation was found to be suitable for enhancing the concentrations of EPA and DHA.