• KSBB Journal
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• v.24 no.3
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• pp.239-245
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• 2009

Enantiopure styrene oxide derivatives are versatile building blocks for the synthesis of enantiopure pharmaceuticals. Styrene monooxygenase (SMO) catalyzes an asymmetric addition of an oxygen atom into a double bond of vinylaromatic compounds. SMO is a commercially potential biocatalyst to synthesize a variety of enantiopure epoxides with high enantiopurity and recovery yield. In this paper development of SMO biocatalyst and commercial feasibility of SMO-catalyzed asymmetric synthesis of enantiopure stylers oxide derivatives are reviewed.

• KSBB Journal
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• v.23 no.5
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• pp.369-374
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• 2008

The effects of reaction temperature and the addition of various detergents on the enantioselective hyrolysis activity of the recombinant Escherichia coli containing the epoxide hydrolase (EH) gene of Rhodotorula glutinis were investigated for the production of enantiopure styrene oxide. The recombinant E. coli harboring the EH gene from R. glutinis exhibited the enantiopreference toward (R)-styrene oxide with the maximum hydrolytic activity of $165.04{\mu}mol/min/mg$ of dry cell weight (dcw). The addition of 0.5% (w/v) Tween 20 at $10^{\circ}C$ increased the initial hydrolysis rate and enantioselectivity by 1.45-fold and 2.0-fold, respectively. Enantiopure (S)-styrene oxide was prepared with 99% ee enantiopurity and 46.0% yield (theoretical yield=50%) from 20 mM racemic styrene oxide.

• Journal of Life Science
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• v.18 no.1
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• pp.136-142
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• 2008

A recombinant Pichia pastoris carrying double expression cassette of Rhodotorula glutinis epoxide hydrolase(RgEH) gene was developed and used for preparing enantiopure (S)-styrene oxide from racemic mixture of styrene oxide. BglII restriction site of original RgEH gene (pPICZ B/RgEH #2) of previous report was mutated using PCR technique for the construction of double expression cassette containing promoter ($P_{AOX1}$), EH gene and transcription terminator ($TT_{AOX1}$) in pPICZ C vector. Double expression cassette with RgEH was inserted into the chromosomal DNA of P. pastoris. $V_{max}$ ($2.2{\mu}mol\;min^{-1}mg\;dcw^{-1}$) on (R)-styrene oxide of P. pastoris with double expression cassette was about 6-fold higher than that ($0.4{\mu}mol\;min^{-1}mg\;dcw^{-1}$) of P. pastoris with single expression cassette. For the determination of the optimal condition, the effects of detergent and temperature on the enantioselective hydrolytic activity and yield of the enantiomer were investigated. When the reaction was performed at $10^{\circ}C$ for 10 min in the presence of 0.5% Tween 20, enantiopure (S)-styrene oxide with 99.9% ee was obtained as the yield 43.4 % from 20 mM racemic sustrate.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1032-1040
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• 2006

Some Pseudomonas species can grow on styrene as a sole carbon and energy source. From the new isolate Pseudomonas putida SN1, the genes for styrene catabolism were cloned and sequenced. They were composed of four structural genes for styrene monooxygenase (styA and styB), styrene oxide isomerase (styC), and phenylacetaldehyde dehydrogenase (styD), along with two genes for the regulatory system (styS and styR). All the genes showed high DNA sequence (91% to 99%) and amino acid sequence (94% to 100%) similarities with the corresponding genes of the previously reported styrene-degrading Pseudomonas strains. A recombinant Escherichia coli to contain the styrene monooxygenase from the SN1 was constructed under the control of the T7 promoter for the production of enantiopure (S)-styrene oxide, which is an important chiral building block in organic synthesis. The recombinant E. coli could convert styrene into an enantiopure (S)-styrene oxide (ee >99%) when induced by IPTG The maximum activity was observed as 140 U/g cell, when induced with 1 mM IPTG at $15^{\circ}C$.

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.65.2-65.2
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• 2007

See Full Text

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.129-135
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• 2006

A gene encoding for a putative microsomal epoxide hydrolase (mEH) of a zebrafish, Danio rerio, was cloned and characterized. The putative mEH protein of D. rerio exhibited sequence similarity with mammalian mEH and some other bacterial EHs. A structural model for the putative mEH was constructed using homology modeling based on the crystallographic templates, 1 qo7 and 1 ehy. The catalytic triad consisting of $Asp^{233}$, $Glu^{413}$, and $His^{440}$ was identified, and the characteristic features such as two tyrosine residues and oxyanion hole were found to be highly conserved. Based on bioinformatic analysis together with EH activity assay, the putative protein was annotated as mEH of D. rerio. Enantiopure styrene oxide with enantiopurity of 99%ee and yield of 33.5% was obtained from racemic styrene oxide by the enantioselective hydrolysis activity of recombinant mEH of D. rerio for 45 min.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.625-625
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• 2005

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.494-494
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• 2005

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.435-438
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• 2003

Epoxide hydrolase(EH) catalyze the enantioselective hydrolysis of racemic epoxides to corresponding diols. A recombinant Pichia pastoris with EH from Rhodotorula glutinis has been constructed by reverse transcriptase-polymerase chain reaction(RT-PCR). The recombinant biocatalyst enantioselectively hydrolyze (R)-styrene oxide faster than (S)-enantiomer. The catalytic activity of recombinant biocatalyst was 7-fold higher than that of wild-type strain. The recombinant EH biocatalyst can be used for kinetic resolution for the production of enantiopure styrene oxide.

• Applied Chemistry for Engineering
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• v.17 no.5
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• pp.557-560
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• 2006

The epoxide hydrolase (EH) of Aspergillus niger LK was expressed to high levels in Escherichia coli based on codon usage. E. coli, Rosetta (DE3)PLysS, containing a large number of tRNAs for rare-codons was employed as a host strain. The recombinant E. coli expressing A. niger EH showed an enhanced enantioselective hydrolysis activity toward racemic styrene oxide. Enantiopure (S)-styrene oxide with a high enantiopurity of 99% ee was obtained from racemic substrates.