## 3 Results and Discussion  
### Impact on the Growth and Fermentation Kinetics  
Both thiamine and biotin were evaluated for their ability to support the growth of \(S\). _cerevisiae_ in MS300 synthetic must. Significant differences in growth kinetics were observed due to the initial concentration of biotin present in the cultivation medium. Three growth parameters were assessed during the experiment: the maximal specific growth rate (\(\mu_{\rm max}\)) attained during the exponential phase, the generation time (G), the maximal population reached during cultivation (\(y_{\rm max}\)), the duration of the alcoholic fermentation process (\(t_{\rm AF}\)), and the maximal production rate of CO\({}_{2}\) during fermentation (\(r_{\rm CO2 max}\)). The ability of yeasts to complete the fermentation processes, with complete consumption of sugars in the medium, was also evaluated. A strong dose-related effect of biotin on growth appeared throughout yeast monitoring, with significant increases (\(p<0.05\)) arising for all growth parameters (Table 2, Figure 1, Supplementary Table S1). Notable rises in the \(\mu_{\rm max}\) and \(y_{\rm max}\) values, as well as a significant drop in the generation time G values, can be found for initial biotin concentrations as little as 0.5 \(\mu\)g/L in the growth medium, suggesting that low doses of biotin might be sufficient in ensuring the coverage of the yeast requirements in the vitamin. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{3}{c}{**Initial Biotin Concentration (ug/L)**} \\ \cline{2-4}  & **0** & **0.5** & **3** \\ \hline \(\mu_{\rm max}\) (h\({}^{-1}\)) 1 ** & 0.12 \(\pm\) 0.00 2  & 0.15 \(\pm\) 0.01 2  & 0.16 \(\pm\) 0.00 2  \\ G (h) 2  & 5.7 \(\pm\) 0.2 2  & 4.7 \(\pm\) 0.2 2  & 4.6 \(\pm\) 0.2 2  \\ Y\({}_{\rm max}\) (cells/mL) 3 [FOOTNOTE:3]Footnote 3: \(\rm{8.0\times 10^{5}\pm 1.7\times 10^{7}\pm 10^{7}\pm 10^{7}\pm 10^{8}\pm 4.6 \times 10^{7}\pm 10^{7}\pm 10^{8}\pm 6.5\times 10^{7}\pm 10^{8}\pm 10^{8}\pm 6.5\times 10^{7}\pm 10^{7}\pm 10^{ 8}\pm 10^{8}\pm 10^{8}\pm 10^{7}\pm 10^{7}\pm 10^{8}\pm 10^{8}\pm 10^{8}\pm 10^{7}\pm 10^{Such an influence stands as both in regard to the growth celerity, as well as its intensity, allowing for the achievement of higher yeast populations when biotin is sufficiently provided in the growth medium. A saturation effect appeared here, since no further significant increase (\(p>0.05\)) in the yeast maximal population can be found between cells grown in 0.5 \(\mathrm{\SIUnitSymbolMicro g}\)/L or 3 \(\mathrm{\SIUnitSymbolMicro g}\)/L of biotin (Table 2, Figure 1, Supplementary Table S1). However, no significant effect of biotin on the fermentation rates could be found (Table 2, Figure 1), suggesting that the vitamin solely affects growth, and that its deficiencies do not impair the fermentative capacity of the yeast, although in higher populations. While concurrent conclusions of this matter were drawn on anaerobically grown _S. cerevisiae_ yeasts in previous investigations [30], other works rather concluded in, opposingly, a significant influence held by the vitamin on fermentation rates [13; 31]. Although the yeasts used in the assays led by [PERSON] and colleagues were pre-starved in a biotin-deficient medium before inoculation, which might have contributed to inducing the notable differences in behaviors observed here [31], those used by [PERSON] and [PERSON] were rehydrated active dried yeasts, in a similar fashion to the yeasts used in the present work [13]. The essential character of biotin appears to be, however, a strain-dependent character in _S. cerevisiae_, since all strains do not possess the capacity for biotin de novo biosynthesis [32]. It is not impossible, as such, that the difference in fermentative behaviors that appears here might rather reflect  
Figure 1: Growth and fermentation profiles of _S. cerevisiae_ under different biotin and thiamine concentrations.