LIPIDS OF SELECTED MOLDS GROWN FOR PRODUCTION OF N-3 AND N-6 POLYUNSATURATED FATTY-ACIDS

The lipid classes and component fatty acids of seven fungi were examined. Three marine fungi, Thraustochytrium aureum, Thraustochytrium roseum and Schizochytrium aggregatum (grown at 30, 25 and 25-degrees-C, respectively), produced less than 10% lipid but contained docosahexaenoic acid (DHA) up to 30% and eicosapentaenoic acid (EPA) up to 11% of the total fatty acids. Mortierella alpinapeyron produced 38% oil containing solely n-6 polyunsaturated fatty acids (PUFA) with arachidonic acid (AA) at 11% of the total fatty acids. Conidiobolus nanodes and Entomorphthora exitalis produced 25% oil and contained both n-3 and n-6 PUFA, with AA at 16% and 18%, respectively. Saprolegnia parasitica produced 10% oil and contained AA and EPA, respectively, at 19% and 18%. The triacylglycerol fraction always represented the major component at between 44% and 68% of the total lipid. Each fungus, except T. aureum, had the greatest degree of fatty acid unsaturation in the phospholipid fraction. The triacylglycerol fraction of T. aureum was the most unsaturated with DHA representing 29% (w/w) of all fatty acids present. The presence of the enzyme ATP:citrate lyase correlated with the ability of molds to accumulate more than 10% (w/w) lipid when the fungi were grown in nitrogen-limiting media. In those molds that failed to accumulate more than 10% lipid, the enzyme was absent.