DEL MONACO silvana Maria
TOLERANCE TO WINEMAKING STRESS CONDITIONS OF PATAGONIAN STRAINS OF Saccharomyces eubayanus AND Saccharomyces uvarum
ORIGONE, A.; DEL MÓNACO, S. M.; AVILA, J.; GONZÁLES FLORES, M.; RODRIGUEZ, M. E.; LOPES, C. A.
JOURNAL OF APPLIED MICROBIOLOGY
WILEY-BLACKWELL PUBLISHING, INC
Lugar: Londres; Año: 2017 vol. 123 p. 450 - 463
High ethanol concentrations, temperature shock, SO2 exposure and osmotic stress are among the most common stress factors influencing yeast growth and performance during winemaking. In this work, the growth of 19 Saccharomyces uvarum and 13 Saccharomyces 27 eubayanus yeast strains isolated from natural and fermentative habitats from Patagonia was analysed under increasing ethanol concentrations. All strains were able to grow until ethanol concentration of 8% v/v. Strains demonstrating the highest ethanol tolerance were subsequently evaluated in their tolerance to stress factor typically found at initial grape must fermentations (different temperature and pH conditions as well as at SO2 and hexose concentrations) by means of a Central Composite Experimental Design. Only two S. uvarum (NPCC 1289 and 1321) were able to grow in most of the culture conditions. Kinetic parameters analysed (μmax and λ) were statistically affected by temperature, pH and SO2, but not influenced by sugar concentration. The obtained growth model was also used for predicting optimal growth conditions for both strains: 20oC, 0% w/v SO2 and pH 4.5. Our results also indicated that isolates from human-associated environments (S. uvarum38 from apple chichas) presented a higher diversity in the response to different stress factors typical from winemaking than those from natural habitats (for both S. uvarum and S. eubayanus). Data obtained in this work evidence the potential use of two S. uvarum yeast strains as starter cultures in wines fermented at relatively low temperatures (preferably 20oC) and containing low sugar and SO2 concentrations.