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Improvement of enantioselectivity and stability of Klebsiella oxytoca hydrolase immobilized on Eupergit C 250L
Author(s) -
Wang PeiYun,
Tsai ShauWei,
Chen TehLiang
Publication year - 2008
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.1925
Subject(s) - klebsiella oxytoca , biocatalysis , hydrolysis , chemistry , immobilized enzyme , hydrolase , chromatography , covalent bond , kinetic resolution , organic chemistry , enzyme , enantioselective synthesis , catalysis , biochemistry , reaction mechanism , escherichia coli , enterobacteriaceae , gene
BACKGROUND: A simple procedure was employed to covalently immobilize a Klebsiella oxytoca hydrolase (SNSM‐87) onto epoxy‐activated supports of Eupergit C 250L via multipoint covalent attachment. The resultant biocatalyst was explored for the hydrolytic resolution of a variety of ( R , S )‐2‐hydroxycarboxylic acid ethyl esters. RESULTS: With the hydrolytic resolution of ( R , S )‐ethyl mandelate in biphasic media as the model system, optimal conditions of 55 °C, pH 6 buffer and isooctane as the organic phase were selected for improving the enzyme stability (activity retained from 10% to 50% at 96 h) and enantioselectivity ( V S V R −1 value enhanced from 44 to 319) in comparison to the performance of free enzyme. Moreover, the immobilized enzyme retained its activity and enantioselectivity after eight cycles of hydrolysis at 55 °C. When applying the resolution process to other ( R , S )‐2‐hydroxycarboxylic acid ethyl esters, 2.4‐ to 4.0‐fold enhancements of the enantioselectivity in general were obtainable. CONCLUSIONS: The enantioselectivity enhancement, good reusability and easy recovery after reaction indicate that the immobilized SNSM‐87 may have the potential as an industrial biocatalyst for the preparation of optically pure 2‐hydroxycarboxylic acids. Copyright © 2008 Society of Chemical Industry