CONCENTRATION AND PURIFICATION OF STEARIDONIC, EICOSAPENTAENOIC, AND DOCOSAHEXAENOIC ACIDS FROM COD-LIVER OIL AND THE MARINE MICROALGA ISOCHRYSIS-GALBANA

n-3 Polyunsaturated fatty acids (n-3 PUFA) from the marine microalga Isochrysis galbana were concentrated and purified by a two-step process-formation of urea inclusion compounds followed by preparative high-performance liquid chromatography. These methods had been developed previously with fatty acids from cod liver oil. By the urea inclusion compounds method, a mixture that contained 94% (w/w) stearidonic (SA), eicosapentaenoic (EPA), plus docosahexaenoic (DHA) acids (4:1 urea/fatty acid ratio and 4 degrees C crystallization final temperature) was obtained from cod liver oil fatty acids. Further purification of SA, EPA, and DHA was achieved with reverse-phase C-18 columns. These isolations were scaled up to a semi-preparative column. A PUFA concentrate was isolated from I. galbana with methanol/water (80:20, w/w) or ethanol/water (70:30, w/w). With methanol/water, a 96% EPA fraction with 100% yield was obtained, as well as a 94% pure DHA fraction with a 94% yield. With ethanol/water as the mobile phase, EPA and DHA fractions obtained were 92% pure with yields of 84 and 88%, respectively.