Analysis of the Microbial Diversity and Population Dynamics during the Pulque Fermentation Process

Pulque is the most-studied traditional Mexican alcoholic beverage prepared by fermentation of the fresh sap (aguamiel, AM) extracted from different Agave species (maguey) cultivated for pulque production. This beverage has been produced mainly in the Central Mexico Plateau since pre-Columbian times. In this contribution, we report the analysis of the bacterial and fungal diversity through 16S rRNA gene V3-V4 fragment amplicon and ITSR1 sequencing associated with the tissue of the walls (metzal) of the cavity or cajete, where the sap accumulates in producing plants for its daily extraction, in AM, and during four fermentation stages for pulque production. The results led to determining which microorganisms detected in the plant tissue are present in AM and maintained during the fermentation process. The results showed that eight bacterial OTUs (Lactobacillus, Leuconostoc, Weisella, Lactococcus, Acetobacter, Gluconobacter, Zymomonas, and Obesumbacterium) and five fungal OTUs (Kazachstania, Kluyveromyces, Saccharomyces, Hanseniaspora, and the OTU O_Saccharomycetales) were present from metzal to AM and during all the stages of the fermentation analyzed. The detected diversity was considered the microbial core for pulque fermentation, comprising up to similar to 84% of the total bacterial diversity and up to similar to 99.6% of the fungal diversity detected in the pulque produced from three plants of A. salmiana from the locality of Huitzilac, Morelos, Mexico. This study provides relevant information on the potential microorganisms responsible for pulque fermentation, demonstrating that the core of microorganisms is preserved throughout the elaboration process and their association with the AM and fermented beverage physiochemical profile.