## 3 Results  
### Yeast Growth and Ooenological Parameters during Fermentation  
The alcoholic fermentations of the Sauvignon blanc clarified must were conducted at a laboratory scale under different inoculation schemes by using _Saccharomyces_ strains in pure and mixed cultures. The monocultures consisted of a _S. pastorianus_ strain (Sp2) and two _S. cerevisiae_ strains, Sc1 and Sc2. The co-inoculation of the _Saccharomyces_ strains took place in different inoculation ratios (70%-30%, 80%-20%, 90%-10%, 95%-5% and 99%-1% \(w/w\)) of Sp2:Sc1 and Sp2:Sc2 (Table 1). The fermentation kinetics were followed by sugar consumption, while the yeast population dynamics were assessed by plate counting combined with molecular methods, which were performed in order to discriminate the inoculated from the indigenous yeast strains.  
All fermentation trials lead to complete sugar consumption. The inoculation mode affected the growth kinetics of the inoculated strains as well as of the indigenous yeast microbiota (Figure 1). _Saccharomyces pastorisariumus_ reached 6.3 \(\times\) 10\({}^{7}\) CFU/mL after seven days of fermentation, when it was used as a monoculture; while the _S. cerevisiae_ strains reached the same population levels after four days.  
Figure 1: Fermentation kinetics and yeast population dynamics of Sauvignon blanc must which was inoculated with pure **(A–C)** and mixed **(D–H)** cultures of _Saccharomyces_ species. The _S. cerevisiae_ inoculated strains (Sc1 and Sc2) are indicated with grey lines, and the _S. pastorianus_-inoculated strains (Sp2) are indicated with white circles, while the indigenous wild yeast is indicated with black lines. The fermentation follow-up through sugar consumption is indicated with a dashed line. Values are means of two independent experiments.  
Additionally, the indigenous yeast population was close to 10\({}^{4}\) CFU/mL when the strain Sc2 was inoculated, and it was close to 10\({}^{3}\) CFU/mL in the case of Sp2 and Sc1 pure cultures (Figure 1A-C). In the mixed cultures, in terms of the population level, the _S. pastorianus_ strain was always below (approximately 1 log CFU/mL) that of the _S. cerevisiae_ co-inoculated strain, except in the case of Sp2 99%-Sc2 1% (Figure 1 H2), in which both Sp2 and the Sc2 followed comparable growth pattern during the entire fermentation period. The indigenous non-_Saccharomyces_ yeasts exhibited a different growth profile according to the inoculated _Saccharomyces_ strains. When the _S. cerevisiae_ strain 1 was present, the population of the non-_Saccharomyces_ yeast was close to 10\({}^{3}\) CFU/mL, while the presence of the Sc2 strain increased (CFU/mL) the indigenous yeast population by 1 log.  
The oenological parameters were evaluated according to the OIV protocols at the end of the fermentation trials for all produced wines (Supplementary Table S1). The fermentation duration lasted between 10 and 13 days according to the inoculation mode. Statistically significant, but technologically slight differences were observed for the level of the pH and acidity values among the trials. The pure culture of _S. pastorianus_ presented a significantly lower volatile acidity production (0.06 \(\pm\) 0.03 g/L), which was increased in all cases with the presence of the _S. cerevisiae_ strains. As far as the glycerol production was concerned, the presence of the _S. pastorianus_ strain in the mixed inoculation cultures increased (\(p\) < 0.05) the produced levels in comparison to pure cultures of _S. cerevisiae_ for both tested strains. On the contrary, the presence of Sp2 in the mixed cultures significantly decreased (\(p\) < 0.05) the degradation of the L-malic acid compared to the pure cultures of Sc1 and Sc2.