Immobilization of the glycosidases: alpha-L-arabinofuranosidase and beta-D-glucopyranosidase from Aspergillus niger on a chitosan derivative to increase the aroma of wine. Part II

摘要

The purpose of this paper was to study the immobilization of two glycosidases, alpha-L-arabinofuranosidase (EC 3.2.1.55) and beta-D-glucopyranasidase (EC 3.2.1.21), contained in a commercial preparation and purified as reported in Part I. The procedure which proved to be the best is simple and inexpensive to perform, employing the chitosan derivative glyceryl-chitosan, especially synthesized and characterized, as a support. The glycosidases were adsorbed on this support and cross-linked with glutaraldehyde to prevent them from being released into the wine. Subsequent reduction of the biocatalyst with sodium borohydride allowed for improved stability. Finally, the immobilized glycosidases were compared with free ones in terms of optimum pH and temperature, stability over time, and kinetics parameters (K-m and V-max) after which they were employed for aromatizing a model wine solution containing aromatic precursors. (C) 1998 Elsevier Science Inc. [References: 52]