Encapsulation of Trigonopsis variabilis D-amino acid oxidase and fast comparison of the operational stabilities of free and immobilized preparations of the enzyme

✍ Scribed by Jozef Nahalka; Iskandar Dib; Bernd Nidetzky

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 212 KB
• Volume: 99
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.21579

✦ Synopsis

Abstract

A one‐step procedure of immobilizing soluble and aggregated preparations of D‐amino acid oxidase from Trigonopsis variabilis (__Tv__DAO) is reported where carrier‐free enzyme was entrapped in semipermeable microcapsules produced from the polycation poly(methylene‐co‐guanidine) in combination with CaCl~2~ and the polyanions alginate and cellulose sulfate. The yield of immobilization, expressed as the fraction of original activity present in microcapsules, was approximately 52 ± 5%. The effectiveness of the entrapped oxidase for O~2~‐dependent conversion of D‐methionine at 25°C was 85 ± 10% of the free enzyme preparation. Because continuous spectrophotometric assays are generally not well compatible with insoluble enzymes, we employed a dynamic method for the rapid in situ estimation of activity and relatedly, stability of free and encapsulated oxidases using on‐line measurements of the concentration of dissolved O~2~. Integral and differential modes of data acquisition were utilized to examine cases of fast and slow inactivation of the enzyme, respectively. With a half‐life of 60 h, encapsulated __Tv__DAO was ≈720‐fold more stable than the free enzyme under conditions of bubble aeration at 25°C. The soluble oxidase was stabilized by added FAD only at temperatures of 35°C or greater. Biotechnol. Bioeng. 2008;99: 251–260. © 2007 Wiley Periodicals, Inc.