Four pre-selected indigenous yeast strains belonging to Candida guilliermondii (V-2 and V-5), Candida pulcherrima (V-6) and Kloeckera apiculata (V-9), were used as beta-glucosidase (beta GL) and beta-xylosidase (beta XL) sources. The optimization of yeast culture conditions was carried out and the effects of oenological parameters on beta-glycosidase activities were evaluated. C. guilliermondii V2 and C. pulcherrima V6 strains were selected. These strains showed intracellular (C pulcherrima V-6) and parietal (C guilliermondii V-2) Constitutive beta GL and beta XL. The enzymatic activities were active at pH, glucose, ethanol and SO2 concentrations usually found in winemaking and they were able to release monoterpenols and alcohols from grape juice glycoside extracts. Additionally, these yeast strains were not able to produce volatile acidity and off flavour. Regional ecological relevance of these species was also discussed. Our results evidence that the selected C. guilliermondii V2 and C. pulcherrima V6 strains have interesting oenological characteristics and allow us to think in their potential application in winemaking. (C) 2007 Elsevier Inc. All rights reserved.