Physiological characterization of Saccharomyces uvarum and Saccharomyces eubayanus from Patagonia and their potential for cidermaking.

A diversity of yeast strains belonging to the cryotolerant fermentative species S. uvarum and S. eubayanus have been recovered from natural habitats and traditional fermentations in North Patagonia. The aim of this work was to evaluate the most relevant physiological features in a set of Patagonian strains belonging to S. uvarum and S. eubayanus, in order to analyze their potentiality to be used as starter cultures for cidermaking elaborated at low temperature. We evidenced that S. uvarum strains isolated from natural habitats (Araucaria araucana bark) showed similar physiological features to S. eubayanus strains obtained from the same habitat, and different from S. uvarum strains from fermentative environments (apple chichas). We also confirm the capacity of S. uvarum to produce high glycerol levels, low acetic acid and elevated production of the higher alcohol 2-phenylethanol and 2-phenylethyl acetate and demonstrated similar properties in S. eubayanus. Finally, we evidenced for the first time the antagonistic activity of S. eubayanus and selected three strains (two S. uvarum and one S. eubayanus) bearing the best combination of features to be used as a starter culture in cidermaking.