Title: A comparative study of the wine fermentation performance of Saccharomyces paradoxus under different nitrogen concentrations and glucose/fructose ratios Authors:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 Aims: The main goal of the present study is to determine the effects of different nitrogen concentrations and glucose/fructose ratios on the fermentation performance of Saccharomyces paradoxus, a non-conventional species for wine making. Methods and Results: Ethanol yield, residual sugar concentration, as well as glycerol and acetic acid production were determined for diverse wine fermentations conducted by S. paradoxus. Experiments were also carried out with a commercial S. cerevisiae wine strain used as control. The values obtained were compared to test significant differences by means of a factorial ANOVA analysis and the Scheffé test. Our results show that S. paradoxus strain was able to complete the fermentation even in the nonoptimal conditions of low nitrogen content and high fructose concentration. In addition, the S. paradoxus strain showed significant higher glycerol synthesis and lower acetic acid production than S. cerevisiae in media enriched with nitrogen, as well as a lower, but not significant, ethanol yield. Conclusions: The response of S. paradoxus was different with respect to the commercial S. cerevisiae strain, especially to glycerol and acetic acid synthesis. Significance and Impact of the Study: The presented study has an important implication for the implementation of S. paradoxus strains as new wine yeast starters exhibiting interesting enological properties.