Survival of commercial yeasts in the winery environment and their prevalence during spontaneous fermentations

Abstract

Inoculation of active dry yeasts during the wine-making process has become a common practice in most wine-producing regions; this practice may affect the diversity of the indigenous population of Saccharomyces cerevisiae in the winery. The aim of this work was to study the incidence of commercial yeasts in the experimental winery of Estación de Viticultura e Enoloxía de Galicia (EVEGA) and their ability to lead spontaneous fermentations. To do this, 64 spontaneous fermentations were carried out in the experimental cellar of EVEGA over a period of 7 years. Samples were taken from must and at the beginning, vigorous and final stages of fermentation. A representative number of yeast colonies was isolated from each sample. S. cerevisiae strains were characterised by analysis of mitochondrial DNA restriction patterns. The results showed that although more than 40 different strains of S. cerevisiae were identified, only 10 were found as the dominant strain or in codominance with other strains in spontaneous fermentations. The genetic profiles (mtDNA-RFLPs) of eight of these strains were similar to those of different commercial yeasts that had been previously used in the EVEGA cellar. The remaining two strains were autochthonous ones that were able to reach implantation frequencies as high of those of commercial yeasts. These results clearly indicated that commercial wine yeasts were perfectly adapted to survive in EVEGA cellar conditions, and they successfully competed with the indigenous strains of S. cerevisiae, even during spontaneous fermentations. On the other hand, autochthonous dominant strains that presented desirable oenological traits could be of interest to preserve wine typicity.

Monitoring Seasonal Changes in Winery-Resident Microbiota

“…Hanseniaspora has also been previously reported to colonize winery surfaces [3] and plays an important role in the early stages of wine fermentation [13]. While this yeast is typically present on grapes [17], winery surface establishment may ensure that the same strains are introduced to successive batches and vintages of wine as previously shown for Saccharomyces [19], [20], [21], possibly supporting the reproducibility, as well as regionality, of wine sensory characteristics produced at a given facility. Another yeast detected at lower levels on winery surfaces prior to harvest was Candida zemplinina (Fig.…”

“…Bathed with the nutritious medium of grape juice on a seasonal basis, these surfaces become very promising sites for microbial adsorption and biofilm production, potentially leading to continuous shedding of microbes into successive batches of wine. Specific Saccharomyces strains can become established on winery surfaces, resulting in repeatable detection over multiple years in uninoculated wines [19], [20], [21], [22]. The distribution of non- Saccharomyces fungi on specific winery surfaces has been studied to a limited extent at isolated timepoints using culture-based techniques [2], [3], [23].…”

Geographic delineations of yeast communities and populations associated with vines and wines in New Zealand

“…This may occur by any number of vectors, but humans, insects and birds seem likely candidates, and the two former have been previously implicated (Goddard et al, 2010). The observation that a diverse natural population of S. cerevisiae contributed to these spontaneous ferments is another piece of evidence again showing that spontaneous ferments are not driven by 'escaped' commercial isolates (Blanco et al, 2011), even in large commercial wineries that also run parallel inoculated ferments (as was the case here), but driven by a diversity of natural isolates.…”

The microbial dynamics of wine fermentation

“…Analyses of the yeast populations found on winery surfaces, equipment, and in winery air have also been conducted (Blanco, Orriois, & Losada, 2011;Ciani, Mannazzu, Maringeli, Clemente, & Martini, 2004;Garijo et al, 2008;Garijo et al, 2009;González-Arenzana, Santamaria, López, Tenorio, & López-Alfaro, 2012;Haas et al, 2010;Martini, 2003;Mercado et al, 2004;Ocón, Gutiérrez, Garijo, López, & Santamaria, 2010;Ocón et al, 2013;Renouf et al, 2007;Santamaria, López, López, Garijo, & Gutiérrez, 2008). These studies have demonstrated the role that the winery microbiota are a significant source of pre-fermentation microbial activity in juice and must (Fleet & Heard, 1993;Renouf et al, 2007).…”