FA selectivity of lipases in acyl‐transfer reactions with acetate esters of polyols in organic media

FA reaction selectivity of Burkholderia cepacia, Rhizomucor miehei, and Candida antarctica fraction B lipases was compared between acyl‐transfer and esterification reactions. Multicompetitive reaction mixtures containing a series of n‐chain FA (a C4–C18 series; and a C18∶x series, where X=0‐3 double bonds) and a single acetate ester co‐substrate [triacetin, 1,2‐propanediol (1,2‐PD)diacetate, and 1,3‐PD diacetate] were studied in tert‐butyl methyl ether at an aw of 0.69. For B. cepacia lipase, FA optima for C8, C16, and C18∶2 were observed in all reactions with 1.0‐ to 5.9‐fold differences in FA selectivity. For R. miehei lipase, an optimum for C8 FA was observed in all reactions with 1.2‐ to 6.7‐fold differences in FA selectivity. For C. antarctica lipase, FA optima for C8/C10 were observed in all reactions with 1.0‐ to 2.8‐fold differences in FA selectivity. FA selectivities were broadly modulated upon changing from free polyol to acetate ester co‐substrates for B. cepacia and R miehei lipases, whereas FA selectivity modulations were more specific upon this change in reaction configuration for C. antarctica B lipase. For all lipases, reactivity toward unsaturated C18∶x FA was enhanced in acyl‐transfer relative to esterification reactions with these polyol co‐substrates.