Indigenous yeast communities in the environment of "Rovello bianco" grape variety and their use in commercial white wine fermentation

The indigenous yeast communities associated with several vineyard habitats were analysed. Wild yeasts were isolated, differentiated at strain level and identified. A phylogenetic tree based on partial 26S rRNA genes was constructed. The strains were characterized and the indigenous Saccharomyces cerevisiae GR1 was then used to carry out a vinification process and compared with a commercial yeast. Wines obtained were subjected to chemical and sensory analysis. The comparison between the two products highlighted differences due to the fermenting strains employed. The vineyard environment was found to strongly influence the composition of yeast communities, thus, confirming the theory of 'terroir' on the expression of wines. Moreover, vineyard inhabiting birds were in part responsible for the dissemination of fermentative yeasts during their feeding activities.