Caratterizzazione molecolare di ceppi di Saccharomyces cerevisiae isolati da fermentazioni spontanee di Nebbiolo.

The purpose of this study is to characterize, using molecular methods, yeast strains resistant, type S. cerevisiae, isolated from spontaneous fermentation of Nebbiolo grapes, to allow to study the biodiversity and select test strains for the development of autochthonous starter cultures. Sampling come from the 2009 vintage in the cellar of Fontanafredda, located in Serralunga d'Alba. In particular, were taken into consideration one natural fermentation and one triggered by pied de cuve and during microbiological sampling were isolated colonies with morphology typical of S. cerevisiae type beginning of alcoholic fermentation until the drawing on specific days. Yeasts identified as S. cerevisiae, DNA was extracted, subjected to endonuclease restriction with Sau-3A, Sau-PCR amplification and made to run with gel electrophoresis to obtain fingerprints that allow their characterization. In sum up, by dendrograms results, it was possible to include in the two fermentations sampled that there are never more than three strains that perform properly the alcoholic fermentation, and among them there is always a dominant, prevailing over all. Besides, the different strains in the must seem to be in constant competition each others. Finally, the dominant strain always meet competition from others who try to gain their place in the must, and you can't find it over the drawing.