## 3 Results and Discussion
On the other hand, given the fact that at the increasing Glc\({}_{0}\) concentrations, the initial concentration of glucose imposed on the medium is rather high (\(\approx\)200 g/L), besides potential application of nitrogen-limited conditions, other parameters such as oxidative stress and osmotic stress, that are both linked with high Glc\({}_{0}\) concentration media [46], may have negative impact upon the decrease in the \(Y_{\text{EOH/Glc}}\) values with a glucose concentration increment in the medium. In fact, as far as the ethanol fermentation under high Glc\({}_{0}\) concentrations by _Saccharomyces cerevisiae_ strains is concerned, to alleviate the various environmental stresses imposed by the increased initial \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**(a).** & & & & & & \\ \hline \hline
**Strain** & **Time (h)** & **Glc\({}_{\text{cons}}\) (g/L)** & **X (g/L)** & **EOH (g/L)** & **Glyc (g/L)** & \(Y_{\text{EOH/Glc}}\) **(g/g)** \\ \hline \hline _S. cerevisiae_ LMBF \(\Upsilon\)-35 & 72.0 & 66.9 & 2.5 & 30.1 & 1.4 & 0.45 \\ \hline _S. cerevisiae_ LMBF \(\Upsilon\)-25 & 51.0 & 57.0 & 2.9 & 26.7 & 2.7 & 0.47 \\ \hline _S. cerevisiae_ LMBF \(\Upsilon\)-54 & 52.0 & 112.2 & 7.1 & 41.0 & 1.0 & 0.37 \\ \hline _S. cerevisiae_ LMBF \(\Upsilon\)-10 & 48.0 & 78.0 & 3.2 & 30.4 & 0.9 & 0.39 \\ \hline _S. cerevisiae_ Symphony & 36.0 & 93.0 & 5.9 & 32.6 & 0.5 & 0.35 \\ \hline _S. cerevisiae_ Cross X & 34.0 & 89.1 & 4.0 & 40.0 & 1.9 & 0.45 \\ \hline _S. cerevisiae_ Passion Fruit & 24.0 & 92.9 & 5.1 & 43.1 & 1.6 & 0.46 \\ \hline \hline
**(b).** & & & & & & \\ \hline \hline
**Strain** & **Time (h)** & **Glc\({}_{\text{cons}}\) (g/L)** & **X (g/L)** & **EOH (g/L)** & **Glyc (g/L)** & \(Y_{\text{EOH/Glc}}\) **(g/g)** \\ \hline _S. cerevisiae_ LMBF \(\Upsilon\)-35 & 95.0 & 166.8 & 2.7 & 40.9 & 6.4 & 0.25 \\ \hline _S. cerevisiae_ LMBF \(\Upsilon\)-25 & 68.0 & 165.5 & 2.6 & 47.4 & 5.2 & 0.29 \\ \hline _S. cerevisiae_ LMBF \(\Upsilon\)-54 & 168.0 & 179.3 & 6.1 & 68.0 & 6.3 & 0.38 \\ \hline _S. cerevisiae_ LMBF \(\Upsilon\)-10 & 72.0 & 117.1 & 3.9 & 40.0 & 3.1 & 0.34 \\ \hline _S. cerevisiae_ Symphony & 48.0 & 214.6 & 8.1 & 60.9 & 1.4 & 0.28 \\ \hline _S. cerevisiae_ Cross X & 72.0 & 178.6 & 6.3 & 82.2 & 4.4 & 0.46 \\ \hline _S. cerevisiae_ Passion Fruit & 76.0 & 200.5 & 6.4 & 91.1 & 3.8 & 0.45 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Experimental results originated from kinetics of _S. cerevisiae_ wild strains (LMBF Y-10, Y-25, Y-35 Y-54) and commercial strains (Symphony, Passion Fruit, Cross X) growing in shake-flask glucose-based synthetic media at initial glucose concentration \(\approx\) 100 g/L (a) and \(\approx\)200 g/L (b) when the maximum concentration of ethanol (EtOH\({}_{\text{max}}\)) was achieved. Representations of dry biomass (X, g/L), glucose consumed (Glc\({}_{\text{cons}}\), g/L), ethanol produced (EtOH, g/L) and ethanol conversion yield per sugar consumed (\(Y_{\text{EOH/Glc}}\), g/g). Each experimental point is the mean value of 2 independent measurements (SE for most experimental points \(\leq\) 17%). concentrations of sugar, trials in media rich in Mg\({}^{2+}\) and organic nitrogen (i.e., peptone) seem of importance in order to achieve high ethanol concentrations and yields [47]. In all cases and in all fermentations performed, the intra-cellular polysaccharides were quantified, and \(Y_{\text{IPS/X}}\) values ranging between 4.2-11.0% \(w/w\) were recorded for all strains, all fermentation periods and all culture conditions. The quantity of IPS per DCW (%, \(w/w\)) did not increase as the Glc\({}_{0}\) concentration in the medium increased, suggesting that under the present culture conditions and for the given strains tested, there was not any shift towards the synthesis of endopolysaccharides due to the increase in carbon excess in the medium [29; 42].