Characterization of a novel deep-sea microbial esterase EstC11 for enantioselective resolution of (±)-1-phenylethl acetate

Abstract:

[Background] Chiral phenylethl acetate is a crucial chiral flavor compound and possesses important applications in the fields of food and fine chemicals. The enzymatic synthesis of chiral phenylethl acetate is of great industrial application prospect. [Objective] To characterize a novel microbial esterase EstC11 for enantioselective resolution of (±)-1-phenylethl acetate. [Methods] A microbial esterase EstC11 identified from the deep sea of Western Pacific Ocean was cloned, expressed, and characterized. The optical purity of chiral product (R)-1-phenylethl acetate generated through enzymatic kinetic resolution was increased by optimizing the conditions of enzymatic reactions, such as pH, temperature and organic solvents. [Results] The optimum pH and temperature of EstC11 were 8.5 and 25 °C, respectively. Some metal ions and organic solvents could inhibit the hydrolytic activity of EstC11. Under the optimum reaction conditions (pH 9.0, 50 mmol/L Tris-HCl, 20 °C, 50 mmol/L substrate concentration), the optical purity of (R)-1-phenylethl acetate reached 98% with the yield of 39% after 3 h. [Conclusion] The optical purity and yield of (R)-1-phenylethl acetate were dramatically improved after the optimization of enzymatic reaction conditions. Thus, our study laid the foundation for the application of esterase EstC11 in industry.

Key words:Deep-sea microorganism, esterase, kinetic resolution, (R)-1-phenylethl acetate