: Kefir beverage is a probiotic food associated with health benefits, containing probiotic
microorganisms and biomolecules produced during fermentation. The microbial composition
of these beverages varies among countries, geographical regions, and the substrates, therefore,
the characterization of kefir beverages is of great relevance in understanding their potential healthpromoting and biotechnological applications. Therefore, this study presents the metagenomic and
functional characterization of two Chilean kefir beverages, K02 and K03, through shotgun and
amplicon-based metagenomic, microbiological, chemical, and biochemical studies. Results show
that both beverages’ microbiota were mainly formed by Bacteria (>98%), while Eukarya represented
less than 2%. Regarding Bacteria, the most abundant genera were Acetobacter (93.43% in K02 and
80.99% in K03) and Lactobacillus (5.72% in K02 and 16.75% in K03), while Kazachstania was the most
abundant genus from Eukarya (42.55% and 36.08% in K02 and K03). Metagenomic analyses revealed metabolic pathways for lactose and casein assimilation, biosynthesis of health-promoting
biomolecules, and clusters for antibiotic resistance, quorum sensing communication, and biofilm
formation. Enzymatic activities, microbial β-amyloids, and short-chain fatty acids (acetic acid and
propionic acid) were also detected in these beverages. Likewise, both kefir beverages inhibited
biofilm formation of the opportunistic pathogen Pseudomonas aeruginosa. CLICK TO REVIEW
Keywords: kefir; probiotic; curli; β-amyloids; biofilm inhibitor; short-chain fatty acids