Investigating the effect of lipase from Candida rugosa on the production of EPA and DHA concentrates from Kilka fish (Clupeonella cultiventris caspia)

Candida rugosa lipase (CRL) was used to concentrate n-3 polyunsaturated fatty acids (PUFA) by removing non n-3 PUFA from glycerol backbone of triacylglycerol (TAG) in Kilka fish oil. The acidity value of the reaction mixture was inversely proportional to the concentrated glyceride yield, with a correlation coefficient (R2) ranging from 0.82 to 0.98. Releasing the fatty acids from TAGs was significantly (P < 0.05) increased by decrease in water-to-oil ratio from 3 to 1, or by increasing the amount of enzyme (0.50-2%) over 3 h of reaction time. The lipase preference for the constituent fatty acids was in the decreasing order: palmitoleic acid > oleic acid ≥ palmitic acid > stearic acid > EPA > DHA. The discrimination of CRL against eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) was significantly reduced throughout the reaction time (0-180 min). According to full factorial optimization results, the maximum recovery levels of DHA (72.10%) and EPA (33.60%), as well as minimum recovery levels of SFA (22.49%) and MUFA (18.62%) in the glyceride product were obtained through a condition comprising water-to-oil ratio of 1, 2% enzyme and 1 h, which were considered as optimum conditions.