• Title/Summary/Keyword: enantiopure

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Characterization of Styrene Catabolic Genes of Pseudomonas putida SN1 and Construction of a Recombinant Escherichia coli Containing Styrene Monooxygenase Gene for the Production of (S)-Styrene Oxide

  • Park Mi-So;Bae Jong-Won;Han Ju-Hee;Lee Eun-Yeol;Lee Sun-Gu;Park Sung-Hoon
    • 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 $15^{\circ}C$.

Cloning and Characterization of Zebrafish Microsomal Epoxide Hydrolase Based on Bioinformatics (생물정보학을 이용한 Zebrafish Microsomal Epoxide Hydrolase 클로닝 및 특성연구)

  • Lee Eun-Yeol;Kim Hee-Sook
    • 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.

Optimization of Batch Production of Chiral Phenyl Oxirane by Response Surface Analysis (반응표면분석법을 이용한 광학활성 phenyl oxirane의 회분식생산 최적화)

  • 김희숙;박성훈;이은열
    • Journal of Life Science
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    • v.13 no.6
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    • pp.794-798
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    • 2003
  • Batch production of (S)-phenyl oxirane was investigated using epoxide hydrolase activity of Rhodosporidium toruloides SJ-4. Effect of reaction condition of asymmetric biohydrolysis of racemic phenyl oxirane was analyzed and optimized by response surface methodology. The optimal conditions of pH, temperature and DMSO cosolvent ratio were 7.4, $34^P\circ}C$, and 2.3%(v/v), respectively. The final yield was enhanced up to 67%, and reaction times required to reach 99% ee (enatiomeric excess) decreased down to 50% by response surface methodology Enantiopure (S)-phenyl oxirane with 100% enantiopurity and 24% yield (theoretical yield = 50%) was obtained from racemic substrate.