Genetic and phenotypic diversity of autochthonous Saccharomyces spp. strains associated to natural fermentation of 'Malvasia delle Lipari'

Characterize from both genetic and phenotypic standpoints the indigenous strains of Saccharomyces spp. associated with natural fermentation of 'Malvasia delle Lipari'. A total of 192 yeast isolates were obtained from completed fermentation of a mix of 'Malvasia delle Lipari' (92%) and 'Corinto nero' (8%) grapes in two wineries in Salina Island (Sicily, Italy). Fifty-one Saccharomyces spp. isolates were characterized using ITS-PCR, random amplified polymorphic DNA-PCR and mitochondrial DNA restriction fragment length polymorphism and 12 biotypes were identified. Representative strains of each biotype, tested for their physiological traits, exhibit different killer activity, fermentation vigour, production of hydrogen sulphide and show similar beta-glucosidase and proteolytic activity. It is possible to cluster in different groups naturally occurring indigenous biotypes of Saccharomyces cerevisiae from 'Malvasia delle Lipari' on the basis of molecular profiles. Deeper insight on indigenous wine yeast of a conserved environment. The knowledge gained might offer a contribution to the selection of autochthonous wine yeast as starters for controlled fermentations.