• 제목/요약/키워드: styrene

검색결과 1,677건 처리시간 0.023초

Asymmetric resolution of racemic styrene oxide using recombinant Escherichia coli harboring epoxide hydrolase of Rhodotorula glutinis (Rhodotorula glutinis 유래의 고효율 재조합 Epoxide Hydrolase를 이용한 라세믹 Styrene Oxide의 비대칭 광학분할)

  • Park, Kyu-Deok;Choi, Sung-Hee;Kim, Hee-Sook;Lee, Eun-Yeol
    • KSBB Journal
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    • 제23권5호
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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.

Production of Chiral Styrene Oxide by Microbial Enantioselective Hydrolysis Reaction (미생물 입체선택성 가수분해 반응을 이용한 광학활성 Styrene Oxide 생산)

  • 윤성준;이은열
    • KSBB Journal
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    • 제15권6호
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    • pp.630-634
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    • 2000
  • Chiral epoxides are useful chiral synthons in organic synthesis, and various biological methods have been investigated for their production. In this work, the enantioselective resolution of racemic styrene oxide was investigated using Aspergillus niger sp. for the production of optically pure (S)-styrene oxide. The enantioselectivity and initial hydrolysis rates of the racemic substrate were highly dependent of the pH, temperature, and the volume ratio of cosolvent. Experimental sets of pH, temperature, and the volume ratio of cosolvent were investigated using a central composite experimental design, and reaction conditions were optimized by response surface analysis. The optimal conditions of pH, temperature, and the volume ratio of cosolvent were determined to be 7.78, $28.32^{\circ}C$, and 2.4%(v/v), respectively, and optically pure (S)-styrene oxide (>99% ee) was obtained at 35% yield using this microbial enantioselective hydrolysis reaction.

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Quantitative Determination of Styrene in Blood and Mandelic Acid in Urine of the Occupationally Styrene-exposed Workers

  • Yang, Jeong-Sun
    • Archives of Pharmacal Research
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    • 제17권2호
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    • pp.76-79
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    • 1994
  • The concentration of styrne in blood of the occupationally syrene-exposed workers was checked by gas chromatographic headspace analysis. Mandelic acd in urine, that is a major metabolite of styrene, and hippuric acid wre also analyzed by high performance liquid chromatography. For the biological monitoring of styrene-exposed workers, the routine method of the quantitative determination of styrene nad its metabolites in the biolgical samples were studied.

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Platinum(II) Complexes Containing Glycine and Styrene (글리신 및 스티렌의 백금(Ⅱ) 착물)

  • Jun Moo Jin;Peter P. Fu
    • Journal of the Korean Chemical Society
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    • 제21권3호
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    • pp.161-170
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    • 1977
  • Several Pt(II) complexes containing glycine (or glycino anion) and styrene have been prepared, and their structures have been confirmed by infrared spectroscopy. The results confirm the structure of chloro(glycino)(styrene)platinum(II) in which the nitrogen atom of the chelated glycino anion is coordinated to the platinum in the trans position to styrene (N-trans isomer).

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Mechanism of Wrinkle Formation on Styrene-Butadiene-Styrene Block Copolymer via Ion-Beam Irradiation (Styrene-Butadiene-Styrene Block Copolymer 위 이온빔 조사를 이용한 주름 구조 생성 메커니즘 연구)

  • Lee, Ju Hwan;Kim, Dai-Hyun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제34권2호
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    • pp.130-135
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    • 2021
  • Wrinkle patterns were fabricated on styrene-butadiene-styrene (SBS) block copolymer substrates using ion-beam (IB) irradiation with various intensities. The wavelength of the wrinkle pattern increased as the IB intensity was increased from 800 to 1,600 eV. IB irradiation-induced changes in the surface properties that were confirmed via physicochemical surface analyses. X-ray photoelectron spectroscopy analysis revealed chemical surface reformation due to the IB irradiation, resulting in C-O/C=O bonds after IB irradiation that were not reported before. These results indicate that the surface chemical modification caused by IB irradiation is strongly related to the surface modulus, which is important when fabricating wrinkle patterns. Furthermore, a strong IB irradiation induced a strong compressive strain; thus the size of the wrinkle pattern was increased.

Proteomic analysis of serum proteins responsive to styrene exposure (Styrene 노출에 반응을 보이는 혈청 단백질에 대한 프로테오믹스 분석)

  • Kim, Ki-Woong;Heo, Kyung-Hwa;Won, Yong Lim;Jeong, Jin Wook;Kim, Tae Gyun;Park, Injeong
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • 제17권3호
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    • pp.235-244
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    • 2007
  • By comparing the proteins from the workers exposed to styrene with the ones from controls, it may be possible to identify proteins that play a role in the occurrence and progress of occupational disease and thus to study the molecular mechanisms of occupational disease. In order to find the biomarkers for assessing the styrene effects early, before clinical symptoms develop and to understand the mechanisms of adverse health effects, we surveyed 134 employees, among whom 52 workers(30 male and 22 female) were chronically exposed to styrene in 10 glass-reinforced plastic boat manufacturing factories in Korea and 82 controls had never been occupationally exposed to hazardous chemicals including styrene. The age and drinking habits and serum biochemistry such as total protein, BUN and serum creatinine in both groups were significantly different. Exposed workers were divided into three groups according to exposure levels of styrene(G1, below 1/2 TLV; G2, 1/2 TLV to TLV; G3, above TLV). The mean concentration of airborne styrene in G1 group was $10.93{\pm}11.33ppm$, and those of urinary mandelic acid(MA) and phenylglyoxylic acid(PGA) were $0.17{\pm}0.21$ and $0.13{\pm}0.11g/g$ creatinine, respectively. The mean concentration of airborne styrene in G2 and G3 groups were $47.54{\pm}22.43$ and $65.33{\pm}33.47ppm$, respectively, and levels of urinary metabolites such as MA and PGA increased considerably as expected with the increase in exposure level of styrene. The airborne styrene concentration were significantly correlated to the urinary concentration of MA(r=0.784, p=0.000) and PGA(r=0.626, p<0.001). In the 2D electrophoresis, the concentration of five proteins including complement C3 precursor, alpha-1-antitrypsin(AAT), vitamin D binding protein precursor(DBP), alpha-1-B-glycoprotein(A1BG) and inter alpha trypsin inhibitor(ITI) heavy chain-related protein were significantly altered in workers exposed to styrene compared with controls. While expression of complement C3 precursor and AAT increased by exposure to styrene, expression of DBP, A1BG and ITI heavy chain-related protein decreased. These results suggest that the exposure of styrene might affects levels of plasma proteinase, carriers of endogenous substances and immune system. In particular, increasing of AAT with the increase in exposure level of styrene can explain the tissue damage and inflammation by the imbalance of proteinase/antiproteinase and decrease of DBP, A1BG and ITI heavy chain-related protein in workers exposed to styrene is associated with dysfunction and/or declination in immune system and signal transduction

Synthesis of Sulfonated Hollow PP-g-Styrene Fibrous Ion-exchange Membrane and Separation of BSA Protein (술폰화 PP-g-Styrene 중공사 이온교환막의 합성과 BSA 단백질 분리에 관한 연구)

  • 황택성;이진혁
    • Polymer(Korea)
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    • 제26권4호
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    • pp.415-421
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    • 2002
  • A sulfonated PP-g-styrene ion-exchange hollow fiber membrane was prepared by pre-irradiation method with E-beam followed by sulfonation reaction. Degree of grafting increased with the increase of styrene monomer concentration and showed the maximum value of 128% at 80% of styrene monomer composition. Sulfonation yield increased with the degree of grafting. At 100% degree of grafting, sulfonation yield showed the maximum value of 13.4%. Ion exchange capacity of sulfonated HPP-g-styrene of 3.42 meq/g was attained, resulting in the remarkable increase of adsorption ability BET analysis proved that the surface area of sulfonated HPP-g-styrene was 62.54 $m^2/g$ and the mean pore size was 25 $\AA$. From the BSA adsorption experiments, the adsorption amount of BSA was increased with sulfonation. At 13.4% sulfonation yield the adsorption amount of BSA was maximum as 3.8 mg/g. Sulfonated HPP-g-styrene was synthesized successfully and suitable for the adsorption and separation of BSA.

Development of Recombinant Pseudomonas putida Containing Homologous Styrene Monooxygenase Genes for the Production of (S)-Styrene Oxide

  • Bae, Jong-Wan;Han, Ju-Hee;Park, Mi-So;Lee, Sun-Gu;Lee, Eun-Yeol;Jeong, Yong-Joo;Park, Sung-Hoon
    • Biotechnology and Bioprocess Engineering:BBE
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    • 제11권6호
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    • pp.530-537
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    • 2006
  • Recently isolated, Pseudomonas putida SN1 grows on styrene as its sole carbon and energy source through successive oxidation of styrene by styrene monooxygenase (SMO), styrene oxide isomerase (SOI), and phenylacetaldehyde dehydrogenase. For the production of (S)-styrene oxide, two knockout mutants of SN1 were constructed, one lacking SOI and another lacking both SMO and SOI. These mutants were developed into whole-cell biocatalysts by transformation with a multicopy plasmid vector containing SMO genes (styAB) of the SN1. Neither of these self-cloned recombinants could grow on styrene, but both converted styrene into an enantiopure (S)-styrene oxide (e.e. > 99%). Whole-cell SMO activity was higher in the recombinant constructed from the SOI-deleted mutant (130 U/g cdw) than in the other one (35 U/g cdw). However, the SMO activity of the former was about the same as that of the SOI-deleted SN1 possessing a single copy of the styAB gene that was used as host. This indicates that the copy number of styAB genes is not rate-limiting on SMO catalysis by whole-cell SN1.

Styrene Degradation in a Polyurethane Biofilter Inoculated with Pseudomonas sp. IS-3

  • KIM JAISOO;RYU HEE WOOK;JUNG DONG JIN;LEE TAE HO;CHO KYUNG-SUK
    • Journal of Microbiology and Biotechnology
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    • 제15권6호
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    • pp.1207-1213
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    • 2005
  • In a search for bacteria capable of degrading styrene better than previously isolated strains, bacterium IS-3 was isolated from activated sludge and found to be most closely related to Pseudomonas sp. Styrene degradation by this strain was tested in liquid cultures and polyurethane-packed biofilters. In liquid cultures, the rate of styrene degradation by this bacterium increased from 24.93 to $76.53\;{\mu}mol\;g^{-1}\;DCW\;H^{-1}$ for an initial mass range from 8.7 to $34.8{\mu}mol$. The maximum styrene elimination capacity was 580-635 $g/m^{3}\cdot$h at a space velocity (SV) of 50-200/h. The critical elimination capacities guaranteeing $95\%$ removal of the input styrene were determined to be 635, 170, and 38 $g/m^{3}\cdot$h, respectively, at SVs of 50, 100, and 200/h. Kinetic analysis revealed that the maximum styrene elimination velocity ($V_{m}$) for this biofilter was 1,000 g/m$\cdot$h, and the saturation constant ($K_{m}$) was 454 ppmv. Together, these results suggest that a polyurethane biofilter containing Pseudomonas sp. IS-3 could have potential practical applications for the effective removal of styrene gas.

Development of Asymmetric Resolution System for the Production of Chiral Styrene Oxide by Microbial Epoxide Hydrolase (미생물 유래의 Epoxide Hydrolase를 이용한 Chiral Styrene Oxide 생산용 비대칭 광학분할시스템개발)

  • 이지원;윤여준;이은열
    • Journal of Life Science
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    • 제12권5호
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    • pp.584-588
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    • 2002
  • Asymmetric enantioselective resolution system using epoxide hydrolase activity of Aspergillus niger LK was developed and operated for the production of optically pure styrene oxide. Two-phase hollow-fiber reactor system was employed for the enhanced solubility of racemic styrene oxide in organic phase and protection of epoxide hydrolase activity in aqueous phase. For the removal of phenyl-1,2-ethandiol, the inhibitor of epoxide hydrolase, cascade hollow-fiber reactor system was also developed. Chiral (S)-styrene oxide (39 mM in dodecane) could be asymmetrically resolved with high enantiopurity (> 99% ee) using these reactor system.