RODRIGUEZ maria eugenia
congresos y reuniones científicas
Characterization of glycosidase activities of indigenous wine yeast from Comahue region
Villa Carlos Paz, Cordoba
Congreso; XXXVIII Reunión Nacional de la S.A.I.B.; 2002
The aims of this work was to characterized glycosidase activities of indigenous wine yeasts in order to use yeasts themselves or their enzymes to increase the varietal character of wine. Twelve indigenous yeast strains belonging to Candida guilliermondii, Candida pulcherrima and Kloeckera apiculata species taxonomically characterized by ITS region PCR/RFLP analysis, were monitored for b-glucosidase (bGL), b-xylosidase (bXL),a-arabinofuranosidase (aAR) and a-rhamnosidase (aRH) activities on agar plate containing different carbon sources and the appropriate 4- methylumbelliferyl glycoside as substrate. Cells grown in liquid YNB containing 0,5% cellobiose, glucose or.rhamnose were used to evaluate glycosidase biosynthesis and location as well as to characterize the enzymatic activities. The glycoside precursors hydrolysis was determined by CGL. The yeast strains showed constitutive bGL and glucose inhibits their synthesis and activity. None of 12 yeast strains produced aAF, constitutive bXL was observed in some strains and only one –C. guilliermondii strain exhibited an inductive aRH. Enzymatic preparations of bound cell wall bGL and aRH (C. guilliermondii) and intracellular bGL (C pulcherrima) were active at pH and ethanol and SO2 concentrations usually found in wine and they released monoterpenoles and other a1cohols and esters from grape juice glycoside extracts. Zymogram and SDS-PAGE of C. guilliermondii and C. pulcherrima revealed the occurrence of the two bands (Mr 95 and 27 kD) exhibiting bGL activity. The results evidence the potential of these yeast glycosidases for enhancing flavors in wine.