International Journal of Applied Microbiology and Biotechnology Research
ISSN: 2053-1818
Vol. 4(6), pp. 75-89, October 2016
doi.org/10.33500/ijambr.2016.04.010



Whole-cell biotransformation with recombinant nitrilase for enantioselective production of (R)-o-Chloromandelic acid

Rui Han, Chen Chen, Fei Wang, Yang Liu, Xuan Y. J. Gong and Lixin Ma

Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, People’s Republic of China.

*To whom correspondence should be addressed. E-mail: malixing@hubu.edu.cn.

Received 02 September, 2016; Received in revised form 26 September, 2016; Accepted 29 September, 2016.

Abstract


Keywords:
Bio-transformation, Nitrilase, (R)-o-Chloromandelic acid, Clopidogrel, Chiral synthesis.


(R)-o-Chloromandelic acid [(R)-o-Cl-MA] is widely used in pharmaceutical production, fine chemical products, asymmetric synthesis, optical resolution and other fields. (R)-o-Cl-MA can be employed to synthesize the (S)-clopidogrel, a thienopyridine-class antiplatelet agent used to inhibit blood clots. Chiral synthesis of (R)-o-Cl-MA proved to be a crucial step since (R)-o-Cl-MA is a direct impact on optical purity of (S)-clopidogrel during the synthetic procedure. In this research, whole cells of Escherichia coli expressing the Alcaligenes faecalis ZJUTB10 nitrilase (AFZN) were explored as catalyst to resolve racemic o-Chloromandelonitrile [(R, S)-o-Cl-MN] into (R)-o-Cl-MA. The optimum temperature of recombinant E. coli expressing AFZN was 45°C and the optimum pH was pH 7.5. The conversion rate of racemic o-Cl-MN reached 99%, and the enantiomer excess against (R)-o-Cl-MA was > 98% within 60 min. The apparent substrate (o-Cl-MN) concentration in reaction system has reached 540 mM (based on the total volume of reaction). Finally, the yield and enantiomer excess against (R)-o-Cl-MA were 96.1 and 99.2% after recrystallization in toluene, and the space-time yield against (R)-o-Cl-MA reached 6.81 g•L-1•h-1.

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