Identificación de levaduras indígenas mediante AFLP y estudio de su influencia en fermentaciones dirigidas para la obtención de vinos de autor.

Abstract

Wine production is one of the oldest and most ingrained biotechnological process in human history worth more than 4 billion euros in 2016. In the last years, this ancient industry started a new era to adapt production to the interests of consumers, who demand high quality natural and organic wines. The employment of clear-cut methods of cultivation, harvesting and fermentation, as stated within the framework of the “EU No 203/2012 of 8 March 2012” and the use of indigenous yeasts from their cultivars and wineries, guarantee the production of wines with unique flavor and aroma qualified by the region's “terroir”. The focus of this work has been the study of the indigenous yeasts isolated from the wineries Aster and Diaz Bayo from Ribera del Duero (P.D.O). One thousand two hundred indigenous yeasts from the cellar and grapes of the wineries were isolated and characterized using molecular standardized methods (ITS-RFLP and sequencing of D1/D2 regions). Then, 43 wild yeasts were characterized using AFLP (Amplified Fragment Length Polymorphism) molecular markers obtained with seven primer pairs fluorescent labelled (FAM or HEX). Using the species and strain specific AFLP alleles amplified with two primer sets (S and J) a database was created for the identification of wine yeasts in must samples, without the use of microbial cultures. In addition, fermentation experiments using Tempranillo´s commercial wort were carried out with selected wild strains in order to observe their influence in the production of organic compounds determining the wine aroma. Three yeast strains, Lt1, Mp3 and Hu1, standed out since they produced ethyl hexanoate, ethyl octanoate and 2-phenylethanol, which contribute to the fruity (banana, peach notes) and floral (rose notes) aromas in Tempranillo wine.