Published in the journal PNAS, the findings reveal that traditional caprine milk fermentation practices in the Central Asian valley preserve a complex microbial ecosystem that explains the digestive and immunological benefits of the drink, gazzetta.it reported.
The study provides the first genetic mapping of ancestral kefir yeasts, contrasting them against more than one thousand other strains of Saccharomyces cerevisiae. Cavalieri explained that the traditional preparation methods in the Yaghnob Valley have been passed down through generations.
Microbial Ecosystem and Galactose Digestion Mechanisms
Kefir functions as a biological ecosystem comprising milk bacteria and yeasts spanning at least twenty distinct species. This combination of bacteria and yeasts digests lactose naturally, generating an acidic environment with an alcohol content below 0.2 percent that prevents pathogenic agents from multiplying, according to Cavalieri.
By mapping the entire DNA of the Yaghnob yeasts, the Italian researchers placed these strains at the root of the genealogical tree for S. cerevisiae strains derived from other fermented milk products. These ancestral yeasts exhibit unique enzymatic activities, specifically demonstrating high efficiency in digesting galactose, one of the primary sugars found in milk.
This metabolic capability allows the yeasts to compete effectively with lactobacilli for galactose. The process enables a microorganism-rich kefir to restore balance to the human intestinal microbiota, remain tolerable for individuals with lactose intolerance, and reduce inflammation.
Co-Evolution of Yeasts and Human Communities
Beyond immediate digestive metrics, the findings highlight a deep evolutionary relationship between humans and microorganisms. The Yaghnob yeasts appear to have co-evolved alongside human communities that produced fermented milk, adapting across centuries to a specific nutritional environment.
These evolutionary adaptations produced enzymatic characteristics absent in strains cultivated in other contexts. Cavalieri noted that the results expand scientific understanding of yeast ecology and evolution in parallel with human societies, pointing to natural remedies that extend beyond baking and brewing applications.
Frequently Asked Questions
Where is the Yaghnob Valley located?
The Yaghnob Valley is a remote region situated in Tajikistan where traditional goat’s milk fermentation methods have been preserved across generations.
What unique enzymatic ability do the ancestral Yaghnob yeasts possess?
The yeasts demonstrated high efficiency in digesting galactose, allowing them to compete with lactobacilli and help restore balance to the human intestinal microbiota.