HYDROLYSIS AND ESTERIFICATION OF ACYLGLYCEROLS AND ANALOGS IN AQUEOUS-MEDIUM CATALYZED BY MICROBIAL LIPASES

The stereoselectivity of microbial lipases from Chromobacterium viscos um (CVL) and Rhizopus arrhizus (RAL) towards monoacylglycerols (rac-1( 3)-oleoylglycerol and 2-oleoylglycerol), diacylglycerols (1,3-dioleoyl glycerol and rac-1,2(2,3)-dioleoylglycerol) and 2-O-ether analogs (rac -1(3)-oleoyl-2-O-hexadecylglycerol and rac-1(3)-octanoyl-2-O-hexadecyl glycerol) was determined. The results of the hydrolysis of 2-O-ether a nalogs confirmed the importance of the substituent at C-2 of acylglyce rols in the stereoselective recognition by microbial lipases and also showed that acylation of mono- and diradylglycerols with oleic acid ov erlaps the hydrolysis reaction in aqueous medium. With the short-chain , water-soluble octanoic acid no significant esterification occurred. Using rac-1,2(2,3)-dioleoylglycerol as a substrate for the hydrolysis with RAL and CVL, the appearance of 1,3-dioleoylglycerol and of 1(3)-m onooleoylglycerol was demonstrated. The possibility of chemical vs. en zyme-catalyzed isomerization of 1,2-dioleoylglycerol and of 2-oleoylgl ycerol is discussed.