title: Preparative-scale kinetic resolution of racemic styrene oxide by immobilized epoxide hydrolase.
abstract: Epoxide hydrolase from Aspergillus niger was immobilized onto the modified Eupergit C 250 L through a Schiff base formation. Eupergit C 250 L was treated with ethylenediamine to introduce primary amine groups which were subsequently activated with glutaraldehyde. The amount of introduced primary amine groups was 220 μmol/g of the support after ethylenediamine treatment, and 90% of these groups were activated with glutaraldehyde. Maximum immobilization of 80% was obtained with modified Eupergit C 250 L under the optimized conditions. The optimum pH was 7.0 for the free epoxide hydrolase and 6.5 for the immobilized epoxide hydrolase. The optimum temperature for both free and immobilized epoxide hydrolase was 40 °C. The free epoxide hydrolase retained 52 and 33% of its maximum activity at 40 and 60 °C, respectively after 24h preincubation time whereas the retained activities of immobilized epoxide hydrolase at the same conditions were 90 and 75%, respectively. Immobilized epoxide hydrolase showed about 2.5-fold higher enantioselectivity than that of free epoxide hydrolase. A preparative-scale (120 g/L) kinetic resolution of racemic styrene oxide using immobilized preparation was performed in a batch reactor and (S)-styrene oxide and (R)-1-phenyl-1,2-ethanediol were both obtained with about 50% yield and 99% enantiomeric excess. The immobilized epoxide hydrolase was retained 90% of its initial activity after 5 reuses.
authors.affiliation: Department of Chemistry, Faculty of Arts & Sciences, University of Cukurova, 01330 Adana, Turkey. dozyildirim@gmail.com
authors.forename: Deniz
authors.initials: D
authors.lastname: Yildirim
authors.forename: S Seyhan
authors.initials: SS
authors.lastname: Tükel
authors.forename: Dilek
authors.initials: D
authors.lastname: Alagöz
authors.forename: Ozlem
authors.initials: O
authors.lastname: Alptekin
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000378:metabolism*; D004851:Epoxide Hydrolases / Q000378:metabolism*; D004852:Epoxy Compounds / Q000737:chemistry / Q000302:isolation & purification*; D007700:Kinetics; D011108:Polymers; D013237:Stereoisomerism
chemical_list: D004800:Enzymes, Immobilized; D004852:Epoxy Compounds; D011108:Polymers; C065843:Eupergit C; C013690:styrene oxide; D004851:Epoxide Hydrolases