INVESTIGADORES
COMBINA Mariana
capítulos de libros
Título:
Exploring the biodiversity of a wine region: Saccharomyces yeasts associated with wineries and vineyards
Autor/es:
MERCADO L.; COMBINA M.
Libro:
Current Research, Technology and Education Topics in Applied Microbiology and Microbial Biotechnology -Volume 2
Editorial:
Formatex
Referencias:
Año: 2010; p. 1042 - 1053
Resumen:
Saccharomyces yeasts have been used in the fermentation of food and drink products for thousands of years. Wine production is a complex microbiological process involving different S. cerevisiae populations during fermentation. Argentina is the fifth largest wine producer in the world and most of its grape and wine production is located in the west side of the country on the eastern side of the Andes Mountains (between 22º and 42º S). In characterizing a wine region, it is necessary to not only define its microclimate and soil characteristics, but also the yeast populations that are present in the vineyards, grapes and wineries. The objective of the present study was to determine the native strains of Saccharomyces cerevisiae present in the grapes, wineries and wines of the Zona Alta del Río Mendoza (ZARM) region. This region is known worldwide for producing high quality Malbec wines. Two different, but related, aspects were evaluated using a molecular approach for Saccharomyces strain differentiation. First, we tried to elucidate the origin of S. cerevisiae yeasts involved in the spontaneous fermentation of grape musts by evaluating the distribution of these yeasts on winery equipment and determining their contribution to the fermentation process. Their genetic relationships with commercial yeasts were also evaluated. Secondly, we explored S. cerevisiae strain diversity in the ZARM vineyards. The contribution of vineyard Saccharomyces strains to the population responsible for industrial spontaneous fermentations and the level of genetic relationships between these populations were also evaluated. The results showed S. cerevisiae biota resident in both wineries and vineyards. A wide diversity and dynamic behaviour were also found within and between seasons, as was a variable contribution to the fermentation process as well as complex interactions with the commercial yeasts used in the wineries. There was no evidence of a representative strain distributed throughout the viticultural region evaluated. Complex genetic relationships at the molecular level between isolated yeasts which shared the same ecological environment were found. Although a wide diversity was observed, these yeasts shared many characteristics, as evidenced by molecular markers, which suggests that the strong selection pressure exerted by the fermentation process could have generated variability at different levels. Knowledge about the biodiversity of native Saccharomyces strains is essential for the preservation and exploitation of the oenological potential of wine grape growing regions. Although microorganism biodiversity has hardly been considered before, it could be used alongside other tools to help face the effects of climate change on viticulture and the winemaking process