Improvement of enantioselectivity and stability of Klebsiella oxytoca hydrolase immobilized on Eupergit C 250L

Pei Yun Wang, Shau Wei Tsai*, Teh Liang Chen

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

14 Scopus citations


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 languageEnglish
Pages (from-to)1518-1525
Number of pages8
JournalJournal of Chemical Technology and Biotechnology
Issue number11
StatePublished - 2008


  • 2-hydroxycarboxylic acid ethyl esters
  • Covalent immobilization
  • Enantioselective hydrolysis
  • Eupergit C 250L
  • Klebsiella oxytoca hydrolase


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