title: Scalable biocatalytic synthesis of optically pure ethyl (R)-2-hydroxy-4-phenylbutyrate using a recombinant E. coli with high catalyst yield.
abstract: Ethyl (R)-2-hydroxy-4-phenylbutanoate [(R)-HPBE] is a versatile and important chiral intermediate for the synthesis of angiotensin-converting enzyme (ACE) inhibitors. Recombinant E. coli strain coexpressing a novel NADPH-dependent carbonyl reductase gene iolS and glucose dehydrogenase gene gdh from Bacillus subtilis showed excellent catalytic activity in (R)-HPBE production by asymmetric reduction. IolS exhibited high stereoselectivity (>98.5% ee) toward α-ketoesters substrates, whereas fluctuant ee values (53.2-99.5%) for β-ketoesters with different halogen substitution groups. Strategies including aqueous/organic biphasic system and substrate fed-batch were adopted to improve the biocatalytic process. In a 1-L aqueous/octanol biphasic reaction system, (R)-HPBE was produced in 99.5% ee with an exceptional catalyst yield (g product/g catalyst) of 31.7 via bioreduction of ethyl 2-oxo-4-phenylbutyrate (OPBE) at 330 g/L.
authors.affiliation: The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China. Electronic address: yni@jiangnan.edu.cn.
authors.forename: Ye
authors.initials: Y
authors.lastname: Ni
authors.forename: Yuning
authors.initials: Y
authors.lastname: Su
authors.forename: Haidong
authors.initials: H
authors.lastname: Li
authors.forename: Jieyu
authors.initials: J
authors.lastname: Zhou
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Sun
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry / Q000235:genetics; D001412:Bacillus subtilis / Q000201:enzymology; D055162:Biocatalysis; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D004952:Esters / Q000737:chemistry / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D042843:Glucose 1-Dehydrogenase / Q000235:genetics / Q000378:metabolism; D060847:Metabolic Engineering; D010654:Phenylbutyrates / Q000138:chemical synthesis / Q000378:metabolism*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D004952:Esters; D010654:Phenylbutyrates; C572920:ethyl (R)-2-hydroxy-4-phenylbutyrate; D000429:Alcohol Oxidoreductases; C019642:alcohol dehydrogenase (NADP+); D042843:Glucose 1-Dehydrogenase
keywords: (R)-2-hydroxy-4-phenylbutanoate; Asymmetric reduction; Biocatalysis; Carbonyl reductase; Coexpression