A simple method for purifying glycosidases:: α-L-arabinofuranosidase and β-D-glucopyranosidase from Aspergillus niger to increase the aroma of wine.: Part I

The purpose of this paper was to study the purification of two glycosidases, alpha-L-arabinofuranosidase (EC 3.2.1.55) and beta-D-glucopyranosidase (EC 3.2.1.21), contained in a commercial preparation. The final purification procedure entailed precipitation in ethanol, ultrafiltration, adsorption on bentonite, salting with KCl, and ultrafiltration. The procedure is both simple and inexpensive to perform at an industrial level. It allows the recovery of 70% of alpha-L-arabinofuranosidase and 116% of beta-D-glucopyranosidase activities with purification values of 10.4 and 6.4, respectively. The amounts of brown compounds and polysaccharides are also considerably reduced by about 80%. The enzymes thus purified were subsequently characterized in terms of optimum pH and temperature, stability over time, kinetic parameters (K-m and V-max), and then employed for aromatizing a model wine solution containing aromatic precursors extracted from Moscato grape skin. (C) 1998 Elsevier Science Inc.