催化学报 ›› 2016, Vol. 37 ›› Issue (8): 1396-1402.DOI: 10.1016/S1872-2067(16)62495-6

• 论文 • 上一篇    下一篇

一种新颖海洋微生物酯酶的功能鉴定及其在D-乳酸甲酯制备中的应用

王依龙a,b, 张云a,c, 孙爱君a,c, 胡云峰a,c,d   

  1. a. 中国科学院南海海洋研究所, 中国科学院热带海洋生物资源与生态重点实验室, 广东 广州 510301;
    b. 中国科学院大学, 北京 100049;
    c. 中国科学院南海海洋研究所, 广东省海洋药物重点实验室, 广东 广州 510301;
    d. 南海生物资源开发和利用协同创新中心, 广东 广州 510301
  • 收稿日期:2016-05-25 修回日期:2016-06-22 出版日期:2016-07-29 发布日期:2016-08-01
  • 通讯作者: Yunfeng Hu
  • 基金资助:

    中国科学院战略性先导科技专项(XDA11030404);国家自然科学基金(21302199);广州市科技计划项目(201510010012);中国科学院重点项目(KGZD-EW-606).

Characterization of a novel marine microbial esterase and its use to make D-methyl lactate

Yilong Wanga,b, Yun Zhanga,c, Aijun Suna,c, Yunfeng Hua,c,d   

  1. a. Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, Guangdong, China;
    b. University of Chinese Academy of Sciences, Beijing 100049, China;
    c. Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, Guangdong, China;
    d. South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Guangzhou 510275, Guangdong, China
  • Received:2016-05-25 Revised:2016-06-22 Online:2016-07-29 Published:2016-08-01
  • Contact: Yunfeng Hu
  • Supported by:

    This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA11030404), the National Natural Science Foundation of China (21302199), Guangzhou Science and Technology Plan Projects (201510010012) and Key Project from the Chinese Academy of Sciences (KGZD-EW-606).

摘要:

手性药物不同对映体往往表现出截然不同的生理活性和毒性,为了减少有毒副作用的对映体,并降低其生物活性,光学纯手性药物的合成一直是制药行业的研究热点.由于手性药物中间体是合成手性药物的重要构建模块,因此手性药物中间体的合成至关重要.手性乳酸及其酯是合成各类药物、农药和聚合物的重要中间体,在制药工业和材料工业中手性乳酸及其酯的制备非常重要.手性乳酸及其酯可以通过传统的有机化学合成和生物酶催化合成,通过有机化学合成法往往很难得到光学纯度较高的手性乳酸及其酯,而生物酶催化法可以得到光学纯的手性乳酸及其酯,同时避免了有机化学合成所导致的金属残留和环境污染等问题.生物酶法合成光学纯的乳酸及其酯可以通过脱氢酶不对称还原酮的前体得到,然而生物催化使用脱氢酶法需要价格昂贵的辅助因子,如NADH和NADPH.而另外一种生物催化方法是通过利用酯酶或者脂肪酶不对称水解外消旋的酯,从而得到光学纯度较高的手性中间体.目前市场上的L-乳酸甲酯价格不太昂贵,因为L-乳酸甲酯可以直接通过大发酵的方法取代有机化学法和酶法直接得到.然而D-乳酸甲酯不能使用廉价的发酵法直接得到,因而其价格昂贵.生物酶催化法可能会成为制备D-乳酸甲酯的主要方法,因为利用生物酶法可以得到光学纯度较高的D-乳酸甲酯.本文从西太平洋深海来源的微生物Pseudomonas oryzihabitans HUP022中克隆并异源表达了一种新颖酯酶PHE14.通过对酯酶PHE14的酶学性质鉴定表明,酯酶PHE14的最适反应底物为对硝基苯酚乙酸酯(C2),最适pH为9.0,最适温度为60℃.PHE14催化最适反应底物C2的活性达到293.07U/mg,Vmax和Km分别为200μM/(mg·min)和0.24mmol/L.酯酶PHE14对多种有机溶剂、表面活性剂和金属离子都具有非常好的耐受性.深海微生物酯酶PHE14对高浓度NaCl具有很好的耐受性,在4 mol/L NaCl存在下,相对酶活力为71.4%.同时,酯酶PHE14能够催化消旋乳酸甲酯的不对称水解反应制备重要的手性化工产品—D-乳酸甲酯.与先前的一些酯酶拆分的报道不同,有机溶剂和表面活性剂对酯酶PHE14催化的动力学水解反应没有促进作用.而且,本研究是首次通过酶动力学水解拆分反应制备光学纯的D-乳酸甲酯.经过实验优化,在pH 9.0和30℃的条件下,反应产物D-乳酸甲酯的对映体过量值和产率分别为99%和88.7%.深海微生物酯酶PHE14作为一种绿色生物催化剂,在多种工业的不对称合成中都具有非常好的应用潜力.

关键词: 酯酶, 海洋微生物, 生物催化, 动力学拆分, D-乳酸甲酯, 水解反应

Abstract:

A novel marine microbial esterase PHE14 was cloned from the genome of Pseudomonas oryzihabitans HUP022 isolated from the deep sea of the western Pacific Ocean. Esterase PHE14 exhibited very good tolerance to most organic solvents, surfactants and metal ions tested, thus making it a good esterase candidate for organic synthesis that requires an organic solvent, surfactants or metal ions. Esterase PHE14 was utilized as a biocatalyst in the asymmetric synthesis of D-methyl lactate by enzymatic kinetic resolution. D-methyl lactate is a key chiral chemical. Contrary to some previous reports, the addition of an organic solvent and surfactants in the enzymatic reaction did not have a beneficial effect on the kinetic resolution catalyzed by esterase PHE14. Our study is the first report on the preparation of the enantiomerically enriched product D-methyl lactate by enzymatic kinetic resolution. The desired enantiomerically enriched product D-methyl lactate was obtained with a high enantiomeric excess of 99% and yield of 88.7% after process optimization. The deep sea microbial esterase PHE14 is a green biocatalyst with very good potential in asymmetric synthesis in industry and can replace the traditional organic synthesis that causes pollution to the environment.

Key words: Esterase, Marine microorganism, Biocatalysis, Kinetic resolution, D-methyl lactate, Hydrolysis