Liquid lipases for enzymatic concentration of n-3 polyunsaturated fatty acids in monoacylglycerols via ethanolysis: Catalytic specificity and parameterization

[Display omitted] •Five liquid lipases are examined for catalytic ethanolysis of fish oil to produce MAGs.•Lipase TL, Eversa Transform & NS afford faster reaction/higher MAGs yield (>30%).•CAL-A gives MAGs containing the highest n-3 PUFAs (88%), followed by lipase NS (81%).•13C NMR analysis indicates CAL-A/lipase Eversa Transform are non-regiospecific.•Higher activity/lower operation cost endows liquid lipases with competitive advantage. This work examined catalytic specificity and fatty acid selectivity of five liquid lipases C. antarctica lipase A and B (CAL-A/B), and lipase TL (T. lanuginosus), Eversa Transfrom and NS in ethanolysis of fish oil with the aim to concentrate n-3 PUFAs into monoacylglycerols (MAGs) products. Lipase TL, Eversa Transform & NS entail a much faster reaction and produce higher MAGs yield (>30%); whereas CAL-A obtains the highest concentration of n-3 PUFAs/DHA/EPA into MAGs products (88.30%); followed by lipase NS (81.02%). 13C NMR analysis indicates that CAL-B and lipase TL are sn-1,3 specific; but CAL-A and lipase Eversa Transform are non-regiospecific or weak sn-2 specific; which plausibly explains high enrichment effect of the latter two lipases. All liquid lipases are observed reusable for a certain times (lipase Eversa Transform up to 12 times), demonstrating their competitive advantage over immobilized form for industrial application because of their higher activity and cheaper operation cost.