Indigenous wine killer yeasts and their application as a starter culture in wine fermentation

Wine yeast strains were isolated from seven fermentations of the red wines 'Refosk and 'Teran, produced in the southwestern part of Slovenia. Among 61 3 isolated yeast strains, 22 expressed killer activity against the supersen sitive strain Saccharomyces cerevisiae. Killer strains were isolated at dif ferent stages of wine fermentation but did not dominate in any of them. Spe cies identification was based on the combination of RFLP analysis of an amp lified rDNA region and biochemical-physiological tests. Killer isolates wer e identified as S. cerevisiae, Pichia anomala, Pichia kluyveri, Pichia pijp eri, Hanseniaspora uvarum and Candida rugosa. Electrophoretic karyotyping w as used to differentiate strains of the same species. Fermentation properti es of four S. cerevisiae strains that possessed stable killer activity were characterized in fermentations of Malvasia must by studying their populati on dynamics and chemical composition and by sensory analysis of the wines p roduced In order to compare the results, spontaneous fermentations and ferm entations induced by commercial yeast starters were performed concomitantly . The local killer strain S(S)12/10 showed the best fermentation properties and produced wine with favourable characteristics. (C) 2001 Academic Press .