深海来源微生物乙酰酯酶的酶学性质鉴定及拆分制备D-乳酸甲酯

摘要

D-乳酸及其酯是重要的手性药物中间体和手性化工产品.从南海深海芽孢杆菌Bacillus sp. SCSIO15029克隆到一个乙酰酯酶基因bae02030, 表达并鉴定该酶Bae02030的酶学性质.该酯酶的最适pH和最适温度分别为8.5和35℃, 其对多种有机溶剂和表面活性剂具有较好的耐受性.乙酰酯酶Bae02030能够通过水解拆分消旋乳酸甲酯来制备光学纯的D-乳酸甲酯.通过对拆分反应进行优化, 添加体积分数为60%的正庚烷能够改善乙酰酯酶Bae02030的光学选择性, 所制备的D-乳酸甲酯的对映体过量值(e.e.s)超过99%, 转化率(c)为56%.深海微生物来源的乙酰酯酶Bae02030作为生物催化剂在工业上制备手性药物中间体具有较好的应用潜力.%D-lactic acid and its esters are important chiral drug intermediates and chemicals. An acetyl esterase, Bae02030, from Bacillus sp. SCSIO15029 isolated from the deep sea of the South China Sea was cloned, expressed and functionally characterized. The optimum pH and temperature of acetyl esterase Bae02030 were 8.5 and 35°C, respectively. Bae02030 exhibited excellent resistance to most organic solvents and surfactants tested. Bae02030 could generate optically pure D-methyl lactate through resolution of racemic methyl lactate. After process optimization of the enzymatic resolution reactions, the addition of 60% heptane improved the enantio-selectivity of Bae02030. The enantiomeric excess of prepared D-methyl lactate was over 99% and conversion rate reached 56%. Acetyl esterase Bae02030 identified from deep-sea microorganism, as a biocatalyst, possesses great potential in the production of chiral drug intermediates in industry.