## 3 Results and Discussion
### Microbial Identification
In the process of alcoholic beverages, _Saccharomyces cerevisiae_ is the yeast species of globally recognized application for the transformation of sugary substrates to beverages of unique flavor and aroma characteristics. In fermentations for the production of wine, beer, whiskey, requila, mezcal, and other distilled spirits, _S. cerevisiae_ converts the sugary substrates into ethanol, carbon dioxide, and various secondary metabolites, which convene to give a particular flavor in the final spirit. In our work, it was observed that the yeast species _S. cerevisiae_ was present in low strain numbers in the fermented sotol must (Figure 2 and Table S1); however, its contribution to the sensory quality of sotol is of great importance. It is reported that, in spontaneous fermentations, _S. cerevisiae_ is the dominant species as ethanol concentration increases. Nevertheless, this yeast is absent or present in low numbers at the start of the process, leading to the foundation that the fermentation production site is the primary source for this yeast [31]. Additionally, the presence of the dominant _S. cerevisiae_ species  
Figure 2: Relative abundance at the phylum level and counts of filamentous fungi and yeasts in fermented sotol (_Dasyliron_ sp.) must. (**A**) Microbial groups with relative prevalence. (**B**) Filamentous fungi and yeast diversity: number of strains. is attributed to their adaptation capability to stressful environmental conditions, such as increasing ethanol concentrations and temperature changes during the fermentation [41]. Another group of microorganisms identified in the fermentation samples of sotol must was the filamentous fungi shown in Figure 2 and Table S1, of which the _Aspergillus_ genus stands out due to its reported presence in artisanal fermented processes. The employment of _Aspergillus_ species is common in the production of alcoholic beverages formulated with cellulose-containing substrates. These cultures hold cellulose-degrading enzymes that improve the breakdown of polysaccharides and increase the ethanol yield of _Saccharomyces cerevisiae_ strains [42]. Moreover, fermentation with fungal strains (individually and consortium) of _Aspergillus_ has been employed in the degradation of lignocellulosic substrates such as raw sugarcane bagasse and wheat bran. These fermentations show the production of exoglucanase, B-xylosidase, endoglucanase, and manganese peroxidase [43]. The hydrolytic capacity of filamentous fungi enzymes to enhance sensory characteristics has been studied, showing significant levels of enzymes (xylanase, cellulose, amylase, and pectinase) produced by _Aspergillus_ versicolor strains [44], whereas _Aspergillus flavus_ strains are important inulinase production microorganisms [45]. Furthermore, these strains exhibit the ability to produce ascorbic acid, a metabolite that can improve the growth of other cultures during consortium fermentations [46]. The genus _Fusarium_ is a fungi that has the biosynthetic pathways to contribute to the flavor attributes of fermented beverages, as this produces short-chain fatty acids of important flavor attributes such as 4-decanolide [47], which exhibits fruity and peach-like aroma attributes [48]. The fungal genus of _Bionetria_ produces, rather than flavor characteristics, metabolites exhibiting a broad range of antibacterial, antifungal, and anti-dermatophytic activity [49]. For instance, the species _Bionetria_ _achroleuca_ has been reported to produce bioactive polyketide glycosides that inhibit _Candidad albicans_ biofilm formation [50]. Furthermore, this species reports showing fibrinolytic enzyme activity [51]. During the spontaneous fermentation of sotol must, a complex microbial consortium interacts to give the physicochemical and the sensory attributes that distinguish the alcoholic spirit sotol. As a result, filamentous fungi, yeasts, and bacteria play significant roles in producing significant flavor attributes.