Concentrates of DHA from fish oil by selective esterification of cholesterol by immobilized isoforms of lipase from Candida rugosa

Two lipases (Lip A and Lip B), were purified from a commercial lipase prepa ration produced by Candida rugosa and partially characterized. The purified lipases were immobilized on Duolite A 568 and used in the selective esteri fication of cholesterol with free fatty acids from sardine fish oil. The re sults showed that Lip A and Lip B preferentially esterified saturated and m onounsaturated fatty acids allowing a 3.4-fold (Lip B, 24 h) and 4-fold (Li p A, 10 h) enrichment of docosahexaenoic acid in the remaining free fatty a cid fraction. Selectivity towards cicosapentaenoic acid was less pronounced . By this selective esterification docosahexaenoic acid was concentrated fr om 7.4 to 32% with a recovery of 95% of its initial content in sardine fish oil. (C) 2000 Elsevier Science Inc. All rights reserved.