Abstract
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 (VSVR-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.
Original language | English |
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Pages (from-to) | 1518-1525 |
Number of pages | 8 |
Journal | Journal of Chemical Technology and Biotechnology |
Volume | 83 |
Issue number | 11 |
DOIs | |
State | Published - 2008 |
Keywords
- 2-hydroxycarboxylic acid ethyl esters
- Covalent immobilization
- Enantioselective hydrolysis
- Eupergit C 250L
- Klebsiella oxytoca hydrolase