In this study, the yeast strains were isolated from grapes by serial dilution technique to determine their alcohol-, sugar- and themnotolerance. 34 wild type yeast strains were isolated and alcohol-, sugar- and thermotolerance of these strains were determined. The maximum alcohol tolerance was found to be 9% (v/v) in yeast strain which is named Y2. Thennotolerance behavior of 6 strains were investigated. The strains were treated with UV light with intervals of 20, 30, 40 and 50 seconds.
Selected resistant colonies were investigated for alcohol tolerance. It was found that alcohol tolerance increased from 9% (v/v) to 12% (v/v) on Y2 strain
