固定化脂肪酶催化制备L-薄荷醇

Production of L-menthol by immobilized enzyme-catalyzed diastereoselective transesterification

用大孔树脂NKA固定高选择性的脂肪酶,催化有机相中转酯化反应,从而拆分八异构体消旋薄荷醇来制备L-薄荷醇。研究pH、载体与酶比例对固定化酶制备的影响及固定化酶的反应稳定性;考察温度、转酯化过程醇酯比例、及底物醇异构组成变化对拆分效果的影响。结果表明:固定化酶的最适pH为8,载体与酶的比例为5∶1时,所得固定化酶的反应稳定性比游离酶的反应稳定性提高了约50%;转酯化反应的最优温度为40℃,醇酯比例为1.5∶1时最佳,改进八异构体消旋薄荷醇组分比例后,非对映体选择率dep达到了95.1%。

The resolution of eight sereoisomers of menthol to produce L-menthol by enzyme catalyzed transesterification was investigated.The immobilized lipase by macroporous resin NKA was used as the catalyst.The influences of pH,ratio of resin carrier to enzyme on the preparation of immobilized enzyme,the stability of immobilized enzyme were studied.Effects of different temprature,ratio of menthol to ester,change of stereoisomers of menthol on the resolution were investigated as well.The optimum pH,ratio of carrier to enzyme were 8 and 5∶1,respectively.The stability of the immobilized enzyme was improved about 50% compared with the free enzyme.The optimum temperature of transesterification was 40 ℃,while the ratio of menthol to ester was 1.5∶1,the final dep reached 95.1% with the improved substrate.