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

A one-step procedure of immobilizing soluble and aggregated preparations of D-amino acid oxidase from Trigonopsis variabilis (TvDAO) is reported where carrier-free enzyme was entrapped in semipermeable microcapsules produced from the polycation poly(methylene-co-guanidine) in combination with CaCl₂...

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Published in:	Biotechnology and bioengineering 2008-02, Vol.99 (2), p.251-260
Main Authors:	Nahalka, Jozef, Dib, Iskandar, Nidetzky, Bernd
Format:	Article
Language:	eng
Subjects:	Biological and medical sciences Biotechnology Capsules - chemistry D-Amino-Acid Oxidase - isolation & purification D-Amino-Acid Oxidase - metabolism dioxygen encapsulation Enzyme Stability Enzymes, Immobilized - metabolism Fundamental and applied biological sciences. Psychology Half-Life Immobilization of enzymes and other molecules Immobilization techniques immobilized biocatalyst Methods. Procedures. Technologies operational stability poly(methylene-co-guanidine) Saccharomycetales - enzymology stabilization Trigonopsis variabilis
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Summary:	A one-step procedure of immobilizing soluble and aggregated preparations of D-amino acid oxidase from Trigonopsis variabilis (TvDAO) is reported where carrier-free enzyme was entrapped in semipermeable microcapsules produced from the polycation poly(methylene-co-guanidine) in combination with CaCl₂ 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 O₂-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 O₂. 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 TvDAO was [almost equal to]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.
ISSN:	0006-3592 1097-0290