scholarly journals Purification and cDNA Cloning of NADPH-Dependent Aldoketoreductase, Involved in Asymmetric Reduction of Methyl 4-Bromo-3-Oxobutyrate, from Penicillium citrinum IFO4631

2005 ◽  
Vol 71 (2) ◽  
pp. 1101-1104 ◽  
Author(s):  
Hiroyuki Asako ◽  
Ryuhei Wakita ◽  
Kenji Matsumura ◽  
Masatoshi Shimizu ◽  
Jun Sakai ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cdna Cloning ◽  
Cdna Clone ◽  
Asymmetric Reduction ◽  
Optical Purity ◽  
Penicillium Citrinum ◽  
Regeneration System ◽  
Nadph Regeneration ◽  
High Optical Purity

ABSTRACT Penicillium citrinum was found to catalyze the reduction of methyl 4-bromo-3-oxobutyrate to methyl (S)-4-bromo-3-hydroxybutyrate [(S)-BHBM] with high optical purity. From the strain, a cDNA clone encoding a novel NADPH-dependent alkyl 4-halo-3-oxobutyrate reductase (KER) was isolated. Escherichia coli cells overexpressing KER produced (S)-BHBM in the presence of an NADPH-regeneration system.

scholarly journals Tuning a bi-enzymatic cascade reaction in Escherichia coli to facilitate NADPH regeneration for ε-caprolactone production

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jinghui Xiong ◽  
Hefeng Chen ◽  
Ran Liu ◽  
Hao Yu ◽  
Min Zhuo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Binding Sites ◽  
Regeneration System ◽  
Nadph Regeneration ◽  
Whole Cell ◽  
Cyclohexanone Monooxygenase ◽  
Ribosome Binding ◽  
Ribosome Binding Sites ◽  
Whole Cell Biocatalyst ◽  
Substrate Tolerance

Abstractε-Caprolactone is a monomer of poly(ε-caprolactone) which has been widely used in tissue engineering due to its biodegradability and biocompatibility. To meet the massive demand for this monomer, an efficient whole-cell biocatalytic approach was constructed to boost the ε-caprolactone production using cyclohexanol as substrate. Combining an alcohol dehydrogenase (ADH) with a cyclohexanone monooxygenase (CHMO) in Escherichia coli, a self-sufficient NADPH-cofactor regeneration system was obtained. Furthermore, some improved variants with the better substrate tolerance and higher catalytic ability to ε-caprolactone production were designed by regulating the ribosome binding sites. The best mutant strain exhibited an ε-caprolactone yield of 0.80 mol/mol using 60 mM cyclohexanol as substrate, while the starting strain only got a conversion of 0.38 mol/mol when 20 mM cyclohexanol was supplemented. The engineered whole-cell biocatalyst was used in four sequential batches to achieve a production of 126 mM ε-caprolactone with a high molar yield of 0.78 mol/mol.

Synthesis of (S)-Tert-Butyl 3-Hydroxybutyrate by Asymmetric Reduction of Tert-Butyl Acetoacetate with Saccharomyces cerevisiae B5

2013 ◽  
Vol 704 ◽  
pp. 12-17
Author(s):  
Zhi Min Ou ◽  
Wen Fei Feng ◽  
Li Xu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Substrate Concentration ◽  
Asymmetric Reduction ◽  
Optical Purity ◽  
Lower Amount ◽  
High Optical Purity ◽  
Initial Substrate ◽  
Initial Ph ◽  
H 30 ◽  
Initial Substrate Concentration

S)-tert-butyl 3-hydroxybutyrate was synthesized by asymmetric reduction of tert-butyl acetoacetate with Saccharomyces cerevisiae B5 as catalyst. The enantiometric excess of (S)-tert-butyl 3-hydroxybutyrate increased with addition of more amount of substrate. High optical purity of product can be obtained when 6 g/L chloroform was used as inhibitor. The optimum reduction time, temperature, and initial pH of reaction mixture were 60 h, 30 °C, and 6.2. Addition of more biomass and lower amount of substrate helped to get high conversion. Conversion and enantiometric excess of product reached 100% when initial substrate concentration and biomass were 2.0 g/L and 140 g/L with 6 g/L chloroform as inhibitor.

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