A SIMPLE METHOD FOR PURIFYING GLYCOSIDASES - ALPHA-L-ARABINOFURANOSIDASE AND BETA-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 glycosi dases, alpha-L-arabinofuranosidase (EC 3.2.1.55) and beta-D-glucopyran osidase (EC 3.2.1.21), contained in a commercial preparation. The fina l purification procedure entailed precipitation in ethanol, ultrafiltr ation, adsorption on bentonite, salting with KCl, and ultrafiltration. The procedure is both simple and inexpensive to perform at an industr ial level. It allows the recovery of 70% of alpha-L-arabinofuranosidas e and 116% of beta-D-glucopyranosidase activities with purification va lues of 10.4 and 6.4, respectively. The amounts of brown compounds and polysaccharides are also considerably reduced by about 80%. The enzym es thus purified were subsequently characterized in terms of optimum p H and temperature, stability over time, kinetic parameters (K-m and V- max), and then employed for aromatizing a model wine solution containi ng aromatic precursors extracted from Moscato grape skin. (C) 1998 Els evier Science Inc.