AUTHOR=Alonso-del-Real Javier , Lairón-Peris María , Barrio Eladio , Querol Amparo 

TITLE=Effect of Temperature on the Prevalence of Saccharomyces Non cerevisiae Species against a S. cerevisiae Wine Strain in Wine Fermentation: Competition, Physiological Fitness, and Influence in Final Wine Composition

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00150

DOI=10.3389/fmicb.2017.00150

ISSN=1664-302X

ABSTRACT=<p><italic>Saccharomyces cerevisiae</italic> is the main microorganism responsible for the fermentation of wine. Nevertheless, in the last years wineries are facing new challenges due to current market demands and climate change effects on the wine quality. New yeast starters formed by non-conventional <italic>Saccharomyces</italic> species (such as <italic>S. uvarum</italic> or <italic>S. kudriavzevii</italic>) or their hybrids (<italic>S. cerevisiae</italic> x <italic>S. uvarum</italic> and <italic>S. cerevisiae</italic> x <italic>S. kudriavzevii</italic>) can contribute to solve some of these challenges. They exhibit good fermentative capabilities at low temperatures, producing wines with lower alcohol and higher glycerol amounts. However, <italic>S</italic>. <italic>cerevisiae</italic> can competitively displace other yeast species from wine fermentations, therefore the use of these new starters requires an analysis of their behavior during competition with <italic>S. cerevisiae</italic> during wine fermentation. In the present study we analyzed the survival capacity of non-<italic>cerevisiae</italic> strains in competition with <italic>S. cerevisiae</italic> during fermentation of synthetic wine must at different temperatures. First, we developed a new method, based on QPCR, to quantify the proportion of different <italic>Saccharomyces</italic> yeasts in mixed cultures. This method was used to assess the effect of competition on the growth fitness. In addition, fermentation kinetics parameters and final wine compositions were also analyzed. We observed that some cryotolerant <italic>Saccharomyces</italic> yeasts, particularly <italic>S. uvarum</italic>, seriously compromised <italic>S. cerevisiae</italic> fitness during competences at lower temperatures, which explains why <italic>S. uvarum</italic> can replace <italic>S. cerevisiae</italic> during wine fermentations in European regions with oceanic and continental climates. From an enological point of view, mixed co-cultures between <italic>S. cerevisiae</italic> and <italic>S. paradoxus</italic> or <italic>S. eubayanus</italic>, deteriorated fermentation parameters and the final product composition compared to single <italic>S. cerevisiae</italic> inoculation. However, in co-inoculated synthetic must in which <italic>S. kudriavzevii</italic> or <italic>S. uvarum</italic> coexisted with <italic>S. cerevisiae</italic>, there were fermentation performance improvements and the final wines contained less ethanol and higher amounts of glycerol. Finally, it is interesting to note that in co-inoculated fermentations, wine strains of <italic>S. cerevisiae</italic> and <italic>S. uvarum</italic> performed better than non-wine strains of the same species.</p>