LIPIDS AND ULTRASTRUCTURE OF THRAUSTOCHYTRIUM SP ATCC-26185

As a representative of a genus with species considered to be potential commercial producers of the nutritionally important polyunsaturated f atty acid docosahexaenoic acid (DHA), Thraustochytrium sp ATCC 26185 w as investigated to determine its potential for DHA production and lipi d composition. Cells from liquid shake cultures contained 32% (w/w) li pid, 18% of which was nonsaponifiable lipid. The major saturated fatty acids (14:0 and 16:0) comprised up to 59% of the total fatty acids, a nd DHA was up to 25% after 6 d incubation. Squalene represented 63% of the nonsaponifiable lipid, and cholesterol composed 41% of the total sterols. The phospholipids expected for eucaryotic microbes were detec ted with phosphatidylcholine as the major phospholipid at 76% of the t otal. The ultrastructure of this species was similar to other Thrausto chytrium species except that the cells did not have surface scales and they contained unusual membrane-like structures that appeared to be a ssociated with oil formation.