Saccharomyces cerevisiae biodiversity in biodynamics oriented wine farming

In biodynamic oriented wine farming microbial biodiversity is favoured and it is reasonable to expect a major presence of microbes with interesting traits due to the absence o very scarce use of invasive techniques in the vineyard and in the cellar. The aim of the work was the identification and characterization of Saccharomyces cerevisiae wine strains from biodynamic oriented wine farms in different vintages. Yeasts from Syrah fermentations were isolated from different steps of winemaking in 2009, 2010 and 2013 harvests. S. cerevisiae biotypes were molecularly characterized using ITS-PCR and multiplex PCR amplification of microsatellite loci (SC8132X, YOR267C and SCPTSY7). Micro-fermentations of genetically diverse S. cerevisiae were set up to study fermentative traits. Sulphur dioxide, ethanol resistance and production of hydrogen sulphide were chosen as main parameters for technological characterization of isolates. During the harvest of 2009 and 2010, several S. cerevisiae biotypes were individuated during spontaneous fermentation in a biodynamic oriented wine farm located in Tuscany. Some biotypes highlighted good oenological aptitudes allowing their use in guided fermentation. The harvest of 2013 confirmed the presence of several biotypes previously identified in 2009 and 2010. There is a debate about the persistence of “autochthonous” wine yeast strains in the cellar and during winemaking process in the years. The results indicate the presence of the same S. cerevisiae strain in the examed 3 of 5 vinification processes, attesting its presence in the same terroir in different years and overcoming a possible vintage effect.