Abstract: In this study, Cabernet Sauvignon was inoculated with different strains of Saccharomyces cerevisiae, NXU17-26 (natural strain), UCD522 (sensitive strain) and UCD2610 (killer strain), or naturally fermented (control) in order to investigate the effects of these yeast strains on the fermentation performance and yeast diversity during the fermentation process. The results showed that the inoculated strains initiated fermentation more rapidly and exhibited a higher fermentation rate compared to spontaneous fermentation. A total of 480 yeast isolates were classified into 7 phenotypes by using Wallerstein Laboratory Nutrient (WLN) agar. In addition, 26S rDNA D1/D2 domain sequence analysis found that they belonged to 5 species in 4 genera: Hanseniaspora uvarum, Pichia kluyveri, Hyphopichia burtonii, S. cerevisiae and Pichia kudriavzevii. All of the yeast species were found in the spontaneous fermentation, while the yeasts isolated from the inoculated fermentations were H. uvarum and S. cerevisiae. Interdelta fingerprints showed that the inoculated yeasts were the dominant strains in the corresponding fermentations. The natural strain NXU17-26 accounted for 63.46% of the S. cerevisiae strains isolated from the fermentation inoculated with NXU17-26. In the fermentation inoculated with it, the sensitive strain UCD522 accounted for 44.68% of the S. cerevisiae strains isolated, while the indigenous S. cerevisiae NXU18-15 showed strong competitiveness with a percentage of 34.04%. The killer strain UCD2610 accounted for 62.74% of the S. cerevisiae strains during the corresponding fermentation. According to UPGMA cluster analysis, the genetic diversity among S. cerevisiae strains isolated from the same fermentation was small, while the genetic diversity between S. cerevisiae strains isolated from different fermentations was large.

Key words: wine, inoculated fermentation, Cabernet Sauvignon, Interdelta fingerprinting