A novel extracellular beta-glucosidase from Issatchenkia terricola: Isolation, immobilization and application for aroma enhancement of white Muscat wine

Since most Saccharomyces strains show no beta-glucosidase activity, the importance of non-Saccharomyces beta-glucosidases in the development of wine aroma has been highlighted. However, only a few enzymes from yeasts isolated from grape-must and enological ecosystems are active in the stringent conditions of wine and the wine-making process (low pH, high concentrations of ethanol or glucose). A purified extract of extracellular beta-glucosidase from Issatchenkia terricola, proved to be very active in the presence of glucose (100 g/L), ethanol (18%) and metabisulfite (60 mg/L). It is also active and relatively stable at acidic pH over 3.0. Immobilization onto Eupergit C greatly improved its stability, allowing the aromatization of white Muscat wine over a 16-day experiment. The released aroma compounds of control and treated wine were analyzed by GC-MS. The enzymatic treatment significantly increased the amount of monoterpenes and norisoprenoids, showing the potential of the immobilized enzyme for aroma development in wines. (C) 2010 Elsevier Ltd. All rights reserved.