## 3 Results and Discussion
### Specific Footpinting of Strains
The van Krevelen diagrams were based on their O/C and H/C ratios (Figure 1). The wide range \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Strains**} & **Number of** & **Number of** & **Unique** & **Tentative** & **Biomarkers** & **Validated** \\  & **Extracted** & **Biomarkers** & **Molecular** & **Structure** & **(Putative** & **Identification** \\  & **Masses** & **(Level 4)** & **Formulas** & **(Level 3)** & **Identification** & **(Level 2)** \\ \hline S1 & 1513 & 133 & 0 & 6 & 1 & 0 \\ \hline S2 & 1588 & 208 & 0 & 16 & 5 & 1 \\ \hline S3 & 1507 & 127 & 0 & 8 & 4 & 2 \\ \hline S4 & 1669 & 289 & 0 & 15 & 3 & 0 \\ \hline S5 & 1508 & 128 & 0 & 5 & 0 & 0 \\ \hline S6 & 1545 & 165 & 0 & 7 & 5 & 0 \\ \hline S7 & 1510 & 130 & 0 & 7 & 1 & 0 \\ \hline S8 & 2576 & 1162 & 34 & 37 & 10 & 4 \\ \hline S9 & 1602 & 222 & 0 & 17 & 3 & 1 \\ \hline S10 & 1782 & 402 & 0 & 21 & 2 & 0 \\ \hline S11 & 1689 & 309 & 0 & 15 & 0 & 0 \\ \hline S12 & 2051 & 668 & 3 & 32 & 0 & 0 \\ \hline \end{tabular}
\end{table} 
Table 1: Table of extracted, annotated, and identified metabolites according to wine fermented by each strain of _Saccharomyces cerevisiae_ (S1 to S12). of biomarkers of each strain and its composition highlighted the diversity of metabolisms among these strains. Differences in both quantitative and chemical composition could be observed. This metabolic diversity was also illustrated by associated histograms of proportion-marker composition for each strain (Figure 1, Supplementary Figure S3). Thus, S3 was predominantly associated with CHO markers in the area of the van Krevelen diagram where carbohydrate- and polyphenol-derivative compounds were expected. On the contrary, the S4 profile appeared distinctly different from the other strains, with markers mainly composed of CHON and CHONS. The latter were located in the area associated with peptides on the van Krevelen diagram and whose composition is in agreement with [PERSON] et al., 2018 [PERSON] et al. (2018). S5 and S7 were characterized by a large number of CHO, closely followed by CHON, and finally, CHONS. Furthermore, to determine the impact of each strain on their biomarkers, we extracted biomarkers that were significantly more intense (Figure 2A) and less intense (Figure 2B) for each strain. The histogram proportions show the differences in qualitative elemental composition, and the pie charts support the prediction of the families of compounds that can be attributed to each feature. A diagram representing the H/C ratio as a function of the m/z ratio combined with the intensity of each of the features according to their m/z was used. This alternative representation provided additional information on the molecular weight of the biomarkers. All the features were in the mass range of 150 to 650 m/z. We found that the features extracted showed a large variability in composition between those that were less and more intense (Figure 2 and Supplementary Figure S4). For example, we observed that for strain S1, the significantly more intense markers were mainly composed of nitrogen-containing compounds (potential peptides and polyphen-derivative compounds), while the less intense ones were mostly associated with CHO markers in the area of the van Krevelen diagrams where carbohydrate compounds were expected. Biomarkers of S2, whether they were more or less intense, presented peaks with lower intensity in comparison with the other strains. Once the markers were extracted and their nature assumed, it was possible to assign a hypothetical annotation (Level 3) to each of them using databases (KEGG, YMDB, Metlin, Lipidmap, Oligonet). In our case, only 10 to 15% of the specific markers could be annotated in the databases, confirming previous conclusions that evoked the complexity of wine composition and the lack of knowledge on it in the current databases [3; 17; 43]. This step also allowed for the determination of the metabolic pathways associated with the metabolic modifications expressed by the specificity of the markers of each strain (Supplementary Figure S5).