A metagenomics analysis of microbial functional genes linked to vitamins metabolism in the pile fermentation of pu-erh tea

Abstract

The vitamins present in tea beverages are essential nutrients, but their metabolism in the microbial fermentation of pu-erh tea is not fully understood. In this study, 28 vitamins were measured, and microbial metabolic profiles were investigated using metagenomic sequencing in an industrial pile fermentation process of pu-erh tea. After pile fermentation, the contents of 19 vitamins, e.g., adenosine-5′-monophosphate, pantothenic acid, thiamine, and nicotinamide, significantly decreased ( p < 0.05) compared to the raw material. However, the contents of adenine, riboflavin, 5-formyltetrahydrofolate, and ergocalciferol increased significantly ( p < 0.05). The metagenomic sequencing revealed that 73.17% of the genes were bacterial and 26.33% were fungal. In addition, the microbial diversity, population composition, and functional genes of pu-erh tea changed significantly during pile fermentation. At the phylum level, Ascomycota and Proteobacteria had a high relative abundance, while at the genus level, Pantoea and Staphylococcus were dominant. Functional genes related to carbohydrate, amino acid, vitamin, and lipid metabolism were identified. Most importantly, 52 enzymes (4035 genes), mainly from Pantoea , Pseudomonas , Rasamsonia , and Bacillus , were found to be involved in vitamin metabolism. In summary, this study gives novel insights into the pile fermentation mechanism of ripened pu-erh tea by systematically uncovering microbial functional genes linked to changes in vitamins. • Twenty-eight vitamins in an industrial fermentation of pu-erh tea were measured. • Metagenomic sequencing obtained 73.17% bacterial and 26.33% fungal genes. • Functional genes associated with vitamin metabolism were identified. • Four thousand and thirty-five microbial genes encoding 52 enzymes were assigned to the metabolism of vitamins.

Topics & Concepts