Stereoselective acylation of DL-Menthol in organic solvents by an immobilized lipase from Pseudomonas cepacia with vinyl propionate

An effective lipase-catalyzed stereoselective transesterification of (+/-)-menthol in organic solvent with vinyl propionate as acylating agent is described. Immobilization by adsorption and the presence of molecular sieves Improved the formation of (+/-)-menthyl propionate by lipase (PS-30) from Pseudomonas cepacia. The reaction time course, mole ratio of substrates, temperature, amount of enzyme, as well as the effect of various organic solvents, were examined for their influence on the enzymatic stereoselective formation of (-)-menthyl propionate. Among the parameters studied, the stereospecificity toward (-)-menthol decreased significantly as temperature increased but the yields of both enantiomers increased. Organic solvents with log P (partition coefficient) values above 3.5 gave higher yield and stereoselectivity than solvents with lower log P values.