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Improvement on production of (R)-4-Chloro-3-hydroxybutyrate and (S)-3-hydroxy-γ-butyrolactone with recombinant Escherichia coli cells

Paper ID Volume ID Publish Year Pages File Format Full-Text
22370 43273 2006 7 PDF Available
Title
Improvement on production of (R)-4-Chloro-3-hydroxybutyrate and (S)-3-hydroxy-γ-butyrolactone with recombinant Escherichia coli cells
Abstract

(R)-4-Chloro-3-hydroxybutyrate (CHB) and (S)-3-hydroxy-γ-butyrolactone (HL) are used for the synthesis of biologically and pharmacologically important compounds. Enterobacter sp. DS-S-75 was found to have the unique activity to convert (S)-CHB in the racemate to (S)-HL through asymmetric dechlorination, hydrolysis, and lactonization. As a result, the remaining (R)-CHB and formed (S)-HL could be obtained in a one-pot reaction. We purified the CHB degrading enzyme which catalyzing these reactions and isolated the coding gene from the strain DS-S-75 in order to improve the productivity of these compounds using the transformant. Interestingly, the purified enzyme showed not only dechlorinating, but also hydrolyzing activities on CHB and the similar carboxylic esters, it was then designated CHB hydrolase, and appears to be a novel enzyme. The gene had 1101 bp encoding 367 amino acids including a signal peptide composed of 25 residues. The deduced amino acid sequence contained a conserved region generally found in esterases and lipases, but did not have significant similarity. When asymmetric degradation of racemic methyl CHB (CHBM) was performed using a culture broth of Escherichia coli DH5α transformed with the isolated gene, the reaction time was shortened 20-fold over that of the strain DS-S-75, and the maximum concentration of the substrate could be increased from 8% to 15% (w/v). Moreover, both of the obtained residual (R)-CHBM and the formed (S)-HL had high optical purities (>99% e.e.).

Keywords
(R)-4-chloro-3-hydroxybutyrate; (S)-3-hydroxy-γ-butyrolactone; C4 chiral synthon; recombinant Escherichia coli; asymmetric conversion
First Page Preview
Improvement on production of (R)-4-Chloro-3-hydroxybutyrate and (S)-3-hydroxy-γ-butyrolactone with recombinant Escherichia coli cells
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Bioscience and Bioengineering - Volume 101, Issue 2, February 2006, Pages 97–103
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering