Production of Lipids and Phospholipids Containing Eicosapentaenoic Acid and Docosahexaenoic Acid by Thraustochytrium sp.

Thraustochytrids attract biotechnological interest because of their ability to synthesize carotenoids and lipids rich in long-chain omega-3 poly-unsaturated fatty acids: specifically, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These fatty acids can be found among the different lipid classes. In this work, the effects of initial glucose concentration on the growth and the content of lipids and carotenoids in Thraustochytrium sp. RT2316-16 were determined. The fatty acid composition of the neutral and phospholipid fractions was compared. Results obtained in shake flasks showed that increasing the initial glucose concentration from 5 to 20 g L−1 did not affect the growth rate during the first 24 h but increased the maximum biomass concentration 1.4-fold (from 6.3 to 8.6 g L−1) and the carotenoid concentration 1.9-fold while reducing the percentages of EPA and DHA in total fatty acids. DHA was one of the major fatty acids in the phospholipids (37–42% of total fatty acids). The extraction of total lipids from the dry biomass with supercritical CO2 (SCC) had a low yield (59 mg (g DW)−1; 34% of the extraction yield attained with the Bligh and Dyer method). However, when ethanol was used as the co-solvent (SCC-E), the extraction of phospholipids (343 ± 17 mg (g extract)−1) and carotenoids was improved. The composition of the fatty acids in the lipid extracts depended on the lipid extraction method (SCC, SCC-E, Soxhlet with hexane, or the Bligh and Dyer method).