Comprehensive analysis of traditional ethnic starter “Dhaeli”: physicochemical, metagenomic, and metabolomic approaches

Abstract This study provides a comprehensive analysis of the traditional ethnic fermentation starter, Dhaeli , which is commonly used to make the conventional alcoholic beverage Sur by the tribal population in the Bharmour region of Himachal Pradesh, India. The physicochemical, metagenomic, and metabolomic methods were used in the study to characterize the biochemical composition, fungal diversity, and metabolic profile of Dhaeli and its fermented product ( Sur ). Dhaeli was found to contain significant amounts of carbohydrates (62.20%), proteins (13.78%), phenolics, and flavonoids, indicating their role as a preservative of microbial communities. The traditional culture-based methods indicated a higher population of fungal partners (10 5 CFU/g) and lower bacterial colonies (10 2 CFU/g) on non-selective agar, while no colonies of the targeted pathogenic bacterial groups were detected on selective agar. The metagenomic profiling reveals the dominance of Ascomycota, along with beneficial yeast and fungi such as Saccharomyces, Aureobasidium, and Aspergillus , which facilitate efficient carbohydrate breakdown and alcohol production. Apart from different strains of Saccharomyces , other non-Saccharomyces yeast strains were also identified. The metabolomic analysis of the Dhaeli fermented end product Sur , using a mass spectrometer, identified bioactive compounds, including organic acids, phenolic acids, peptides, and microbial secondary metabolites, that contribute to its sensory and nutraceutical properties. This study presents an ethno-microbiological analysis of this traditional starter and its product, necessitating the conservation of this community knowledge for further standardization and commercial applications, thereby enhancing understanding of ethnic biotechnological traditions in the Himalayas.