Microbial Diversity and Functional Potential of Keem: A Traditional Starter Culture for Alcoholic Beverage-Application of Next-Generation Amplicon and Shotgun Metagenome Sequences.

Abstract

"Pakhoi" is an ethnic drink of the Tons valley, Uttarakhand, India produced by fermenting jaggery and barley with the help of a starter culture called "keem". In the present study, we investigated the microbial diversity and associated functional potential of "keem" using shotgun metagenome sequencing and amplicon sequencing. We also compared the taxonomic data obtained using these two sequencing techniques. The results showed that shotgun sequencing revealed a higher resolution of taxonomic profiling as compared to the amplicon sequencing. Furthermore, it was found that the genera detected by shotgun sequencing were valuable for facilitating the fermentation process. Additionally, to understand the functional profiling of the genera, different databases were used for annotation, resulting in a total of 13 metabolic pathways. The five most abundant KEGG functions were genetic information processing, metabolism, translation, cofactor and vitamin metabolism and xenobiotic degradation. In contrast, the top five COG were in order of highest frequency sequences belonging to transcription, followed by general function prediction, carbohydrate transport metabolism, amino acid transport and metabolism and translation and biogenesis. Gene ontology revealed many pathways, biochemical processes and molecular functions associated with the organisms forming the starter culture. Overall, the present study can help to understand the microbial diversity and its role in fermentation of traditional alcoholic beverages using "Keem".