Genome-resolved metagenomics of traditional fermented beverages reveals biosynthetic diversity and informs the rational in silico design of probiotic synthetic communities

Fermentation of foods and beverages represents one of humanitys oldest biotechnologies, generating compounds with demonstrated benefits for gut microbiota modulation, immune regulation, and metabolic health. The global rise of non-communicable chronic diseases, including obesity, type 2 diabetes, and chronic inflammation, has intensified the search for microbiome-based interventions, positioning fermented beverages as promising sources of next-generation probiotics and functional microbial consortia. Beverages such as kefir and kombucha, together with traditional Mexican fermented beverages including pozol and pulque, have been subjected to high-depth shotgun metagenomic studies generating high quality genomic resources. Systematic genomic mining efforts aimed at the functional characterization and biotechnological exploitation of these microbial communities, however, remain scarce. Here, we used a bioprospecting pipeline applied to milk-based kefir, kombucha, pozol, and pulque, integrating targeted genomic mining of genes associated with the biosynthesis of B-group vitamins, short-chain fatty acids, natural products, and CAZymes with potential to enhance starch and dietary fiber utilization upon intestinal colonization. Through genome-scale metabolic modeling of metagenome-assembled genomes, we identified microbial candidates predicted as central producers of secondary metabolites involved in pathogen control. We then used these results for the in silico synthetic assembly of a six-member synthetic microbial community predicted to exhibit stable cooperative growth and high metabolic functionality. Cross-feeding analysis revealed iron as one of the most widely shared elements among community members, with Priestia flexa from pozol, serving as a major donor of compounds involved in iron transport and as a stabilizing element within the synthetic community. This approach allows us to design a theoretical highly functional probiotic community, opening new avenues for the systematic exploitation of microbial diversity for biomedical purposes.