Monitoring of yeastpopulation during fermantation of wine

Sensory quality and technical properties of vine is substantially dependent on yeast species involved in the fermentation processes. To completely understand the role of yeasts in vine production, it is important to determine the taxonomic identity of every yeast species. The task of this project is to characterise the yeast population dynamics during the spontaneous fermentation of grape must. Different geologic and climatic defined regions in Niederösterreich, Burgenland, Wien and Steiermark have been chosen to characterise the yeast flora during the fermentation of white vines ("Grüner Veltliner", "Welschriesling", "Sauvignon Blanc") and a red vine ("Zweigelt"). The Saccharomyces strains as well as non-Saccharomyces strains from fresh pressed grape juice should be isolated and genotypic characterised. A polyphasic methodology including the morphological and physiological examination, PCR-fingerprinting and sequencing of 26S rRNA encoding gene and ITS1/ ITS2 regions is applied to characterise and identify yeasts at species level. On the second hand, the AFLP analysis (amplified fragment length polymorphism) is used to characterise the Saccharomyces cerevisiae strains, which are responsible for the fermentation at a higher ethanol concentration. With these information the yeast flora specific for the selected locations should be characterised and the correlation between the yeast strains and vine type should be estimated. This study open the possibility for selection the autochthonous yeast strains, which could be applied as starter cultures in the vine production