Bundesamt für Weinbau

To evaluate the influence of the genomic properties of yeasts on the formation of wine flavour, genotypic diversity among natural Saccharomyces cerevisiae strains originating from grapes collected in four localities of three Austrian vine-growing areas (Thermenregion: locations Perchtoldsdorf and Pfaffstätten, Neusiedlersee-Hügelland: location Eisenstadt, Neusiedlersee: location Halbturn) was investigated and the aroma compounds produced during fermentation of the grape must of 'Grüner Veltliner' were identified. Amplified fragment length polymorphism analysis (AFLP) showed that the yeast strains cluster in four groups corresponding to their geographical origin. The genotypic analysis and sequencing of the D1/D2 domain of 26S rRNA encoding gene and ITS1/ITS2 regions indicated that the Perchtoldsdorf strains were putative interspecies hybrids between S. cerevisiae and Saccharomyces kudriavzevii. Analysis of the aroma compounds by GS/MS indicated a region-specific influence of the yeasts on the chemical composition of the wines. The aroma compound profiles generated by the Perchtoldsdorf strains were more related to those produced by the Pfaffstätten strains than by the Eisenstadt and Halbturn strains. Similar to the Pfaffstätten yeasts, the putative hybrid strains were good ester producers, suggesting that they may influence the wine quality favourably.