Enzymatic synthesis of diacylglycerols enriched with conjugated linoleic acid by a novel lipase from Malassezia globosa.

摘要

Diacylglycerols (DAG) of conjugated linoleic acid (CLA) were prepared by esterification of glycerol with fatty acids enriched with CLA (FFA-CLA, >95%) in the presence of a novel lipase from Malassezia globosa (SMG1). Lipase SMG1 is strictly specific to mono- and diacylglycerols but not triacylglycerols, which is similar to the properties of lipase from Penicillium camembertii (lipase G 50), but lipase SMG1 showed preference on the production of DAG with the reaction proceeding. Low temperature was beneficial for the conversion of FFA-CLA into acylglycerols, the degree of esterification reached 93.0% when the temperature was 5 degrees C. The maximum DAG content (53.4%) was achieved at 25 degrees C. The rate of DAG synthesis increased as the enzyme loading increased. However, at lipase amounts above 240 U/g mixtures, no significant increases in DAG concentration were observed. The molar ratio of FFA-CLA to glycerol and initial water content were optimized to be 1:3 (mol/mol) and 3%. Lipase SMG1 showed no regioselectivity because the contents of 1,3-DAG and 1,2-DAG were 43.1% and 21.2% based on total content of acylglycerols. By calculating the ratio of 9c, 11t-CLA to 10t, 12c-CLA, it was indicated that lipase SMG1 showed a little preference to 10t, 12c-CLA at the sn-1(3) position of monoacylglycerols (MAG), while no selectivity for 9c, 11t-CLA at the sn-2 position of DAG was obviously found. copyright AOCS 2012.