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研究了在有机溶剂中固定化Alcaligenessp.脂肪酶催化α-氰基-3-苯氧基苄醇乙酯的对映体选择性转酯化反应,考察了不同性质的溶剂和酰基受体对酶的催化活性和选择性以及对产物稳定性的影响.结果发现在弱极性溶剂如正己烷中酶具有较高的催化活性但产物e.e.%值低,而且容易分解;在四氢呋喃等溶剂中酶催化活性相对低,但产物e.e.%值高,也较为稳定;但反应时间太长,会导致产物分解及纯度下降;不同酰基受体对酶反应无显著影响,甲醇为最佳酰基受体,太多醇会导致反应速率下降;溶剂水含量大于2.0%时对酶活性和产物稳定性产生明显不利影响.在优化条件下,酶反应可得到(S)-α-氰基-3-苯氧基苄醇产率>48%,纯度>99%e.e.
Enantioselective transesterification of α-cyano-3-phenoxybenzyl alcohol ethyl ester catalyzed by immobilized Alcaligenessp lipase in organic solvents was investigated. The effect of different solvents and acyl receptors on the activity of enzyme The results showed that the enzyme has high catalytic activity in the presence of weak polar solvent such as n-hexane, but the product has low ee% and is easily decomposed. The enzyme is catalyzed by a solvent such as tetrahydrofuran The activity is relatively low, but the product ee% value is also relatively stable; but the reaction time is too long, will lead to product decomposition and purity decreased; different acyl receptor no significant effect on the enzyme reaction, methanol is the best acyl acceptor, too much Alcohol can cause the reaction rate to decline; when the water content of the solvent is more than 2.0%, the enzyme activity and product stability are obviously adversely affected. Under the optimized conditions, the enzyme reaction can obtain (S) -α-cyano-3-phenoxybenzyl Alcohol yield> 48%, purity> 99% ee