engleski

Screening for the production of extracellular hydrolytic enzymes by Saccharomyces wine yeasts isolated from Croatian wineyards

Winemaking is one of the most ancient of mans technologies and is now one of the most commercially prosperous biotechnological process. Various enzyme activities can improve the process of winemaking and enhance wine quality. Enzymatic activity in yeasts is of interest in connection with the use of the yeasts or the enzymes produced by them to enhance the varietal character of the wine. Among the desirable enzymes in a wine yeasts are the polygalacturonase and _-glucosidase. The aim of this paper were to determine the ability of wine yeasts to produce extracellular pectinases, _-glucosidases and H2S. The 133 Saccharomyces strains used in this study were isolated from different wine growing region in Croatia. Pectinase, _-glucosidases and H2S synthesis were determined on specific agar medium. Three of the tested yeast strains (form Vis Island) showed week _-glucosidase activity. Thirty eight of 133 analyzed isolates showed pectinase enzymatic activity and they were characterized as strong (19 isolates) or moderate (19 isolates) according to discoloration of the halo around the tested strains. Among these producer isolates, 19 were isolated from Drnis region, 14 from Istra, four form Vis Island and one from Ilok. Yeast strains differ widely in their ability to produce H2S. Although most strains produce higher amounts of H2S, there were a few that did not produce or produced low concentration of H2S. Future research should focus on the activity of these enzymes in wine fermentations.

Saccharomyces; extracellular hydrolytic enzymes

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