The relationship between microbial dynamics and dominant chemical components during Liupao tea processing

Abstract

Liupao tea is one kind of dark tea with a unique flavor that can be attributed to the microbiome. Howerver, the role of the microbiome is unknown in pile fermention of Liupao tea. Illumina MiSeq sequencing technology was used in this study to analyze microbial community composition during Liupao tea pile-fermentation. The relationship between microbial colonies and dominant chemical components was also evaluated using Pearson analysis. The result shown that contents of cafeine, gallic acid, free amino acids (Free AA), water-soluble pectins (WSP), tea polysaccharides (TPS), and water-soluble carbohydrate (WSC) all increased during fermentation while contents of epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), gallocatechin gallate (GCG), epicatechin (EC), catechins (+C), water extract (WE), tea polyphenols (TP) and flavonoids decreased. The dominant microbial community succession comprised Sphingomonas (23.68%), Methylobacterium (17.67%), Chryseobacterium (12.55), Aspergillus (16.70%), Cladosporium (8.36%), Penicillium (6.07%), and Blastobotrys (1.54%) in the early stage of fermentation, followed by Staphylococcus (59.05%), Brachybacterium (9.66%), Kocuria (9.81%), Blastobotrys (65.07%), Aspergillus (21.10%), and Rasamsonia (11.06%) at later stages. Amongst these, relative abundances of Lactobacillus in probiotics in middle and late fermentation remained relatively high. Genus of Aspergillus, Blastobotrys, Brachybacterium and Kocuria were signifcantly (P< 0.05) correlated with TP, WSP, WSC, FreeAAs, catechins, flavonoids, cafeine and gallic acid. Therefore, the dominant microbiome in pile fermention of Liupao tea were mainly characterized by Staphylococcus, Aspergillus and other genus, meanwhile Aspergillus, Blastobotrys, Brachybacterium and other genus played an important role in quality formation. This research provides new insights into the relationship between microorganisms and product quality and the development of functional Liupao tea.