Bacterial community and quality characteristics of Pu-erh tea fermented by Weizmannia coagulans

In this study, the probiotics were isolated from ripened Pu-erh tea, and the screened strains were identified by morphological observations and molecular biology method. Probiotic fermented ripened Pu-erh tea (WF) was prepared by inoculation of 10⁶ CFU/g isolated strain in turn fermentation for 30 d and 36 d, respectively. With the fermented samples with no inoculation as control (CK), the differences of bacterial community and quality characteristics of fermented samples were compared. The results showed that a strain PETB0001 was isolated and identified as Weizmannia coagulans from ripened Pu-erh tea. The colony number of W. coagulans in the WF samples was (5.98±1.08)×10⁶ CFU/g, which was 11.59 times higher than that in CK. The linear discriminant analysis effect size (LEfSe) results showed that Bacillus and W. coagulans were biomarkers of WF samples. The fruit flavor, mellow and sweetness of WF samples were significantly increased compared with CK (P<0.05), while the astringency was decreased compared with CK. The contents of soluble sugar, thearubin, methionine, caffeine, catechin, epicatechin, epigallocatechin, epigallocatechin gallate, and taxifolin in WF samples were significantly higher than those in CK (P<0.05). The contents of tea polyphenols, catechin gallate, ellagic acid, myricetin, water extract, and some amino acids in WF samples were significantly lower than those in CK (P<0.05).