Stereoselective acylation of Dl‐menthol in organic solvents by an immobilized lipase from Pseudomonas cepacia with vinyl propionate

Abstract

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. JAOCS 74, 435-439 (1997).

Efficient kinetic resolution of (±)‐menthol by a lipase from Thermomyces lanuginosus

“…The ee p decreased from 99.4% (25 • C) to 98.5% (50 • C). And it decreased significantly and lower than 99% when the temperature was more than 40 • C. The result was similar to Applied Biochemistry that with an immobilized lipase from Pseudomonas cepacia in stereoselective acylation of (±)-menthol with vinyl propionate, where the mole percentage yield of (−)-menthyl propionate increased but the stereoselectivity decreased as the reaction temperature increased [17]. Thus, considering the optical purity of the product and the point of view on green economy, a reaction temperature of 30 • C was selected for the next reactions.…”

“…Wu et al. reported that the lipase from P. cepacia gave a yield of 53.4% for (−)‐menthyl ester with an ee p of 99.1% at the substrate concentration of 0.5 M after 24 H of reaction ( Q = 11.1 mmol/L H). Persichetti et al.…”

“…For example, Xu et al [14] reported that the lipase from C. cylindracea gave a conversion of 39.4% with an ee p of 99.3% at the substrate concentration of 0.1 M after 24 H of reaction (Q = 1.64 mmol/L H). Wu et al [17] reported that the lipase from P. cepacia gave a yield of 53.4% for (−)-menthyl ester with an ee p of 99.1% at the substrate concentration of 0.5 M after 24 H of reaction (Q = 11.1 mmol/L H). Persichetti et al [7] reported that the CRL gave a conversion of 47%-49% with an ee p of more than 99.5% at the substrate concentration of 0.2 M in a reaction time of 0.5-1 H. The last excellent performance was achieved by using the cross-linked enzyme crystals of CRL, which were involved in the preparation of the pure crystal lipase.…”

“…Nowadays, biocatalysis is more and more widely used in optical resolution of racemic compounds to obtain optically pure enantiomers, because of its low energy consumption, high enantioselectivity, high catalytic efficiency, and less byproducts. In enantiomeric kinetic resolution of (±)-menthol, lipases from Candida rugosa (CRL) [5][6][7][8][9][10][11], C. cylindracea [12][13][14][15], Pseudomonas cepacia [2,16,17], and P. fluorescens [3] were investigated extensively and demonstrated high enantioselectivity and catalytic efficiency. But to date, no studies have focused on the lipase from Thermomyces lanuginosus (Lipozyme TL IM).…”

Enzymatic esterification of (−)‐menthol with fatty acids in solvent by a commercial lipase from Candida rugosa

“…The split was 25:1. For identification and quantification of unreacted fatty acids, unreacted menthol and menthyl esters, at first mixtures of these components in different concentrations were prepared using standard fatty acids, standard menthol, and standard menthyl esters prepared according to the method of Wu et al (7). Later these mixtures were analyzed directly without derivatizing the fatty acids by capillary gas chromatography under the same working conditions mentioned above in order to get response factors of reactants and products and to establish calibration curves for them.…”