Abstract:

Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to separate the
bacterial 16S rRNA and fungal 18S rRNA PCR products, and DGGE profiles were applied to analyze the bacterial and
fungal community structures and their changes during the fermentation of Pu-erh tea. Dominant DNA bands on the DGGE
gels were recovered and cloned into E. coli, and the targeted clones were sequenced. Based on the blasted nucleotide
sequences, bacterial 16S rRNA and fungal 18S rRNA Neighbor-Joining phylogenetic trees were constructed. The results
suggested the difference in microbial community structure between tea pile surface and inner was not obvious. Bacterial
and fungal populations revealed a rapid increase after the second fermentation stage, and the structures of bacterial and
fungal communities exhibited a significant change as fermentation time was prolonged. At the last stage of the fermentation
process, the microbial communities were steady; and Aspergillus niger was the dominant species at the early stage and
Bacillus and Arxula adeninivorans were the dominant ones at the late stage.

Key words: Pu-erh tea, 16S rRNA, 18S rRNA, PCR-DGGE, community structure