**Abstract**

The structure of the bacterial community involved in the production of oriental traditional post-fermented tea (Chungtaejeon) was investigated using 16S rRNA gene analysis. The main microorganisms in fermentation process of Chungtaejeon are identified as *Pantoea sp*. and *Klebsiella oxytoca*. Phylogenetic analysis suggested that the taxonomic affiliation of the dominant species in the Chungtaejeon was γ-proteobacteria. The bacterial community size was higher about 100 times in Chungtaejeon compared with other Korean tea and puer-tea. Also, the fungal community size was higher about seven times in the Chungtaejeon than in the other post-fermented teas. However, the archaeal community size was highest about six times in the Chungtaejeon. Therefore, the bacteria, fungal and archaeal community sizes were highest for Chungtaejeon than in the seven post-fermented teas. As a result, the microbial communities of Chungtaejeon were the largest compared with other teas. The catechin content decreased from 12.10 to 3.80 mg/g, and epicatechin (EC) and gallic acid contents were increased to 28.50 and 8.02 mg/g, respectively, during manufacturing. The *Pantoea sp.* may perform an important role for manufacturing and fermentation to gallic acid from catechins of Chungtaejeon.

**Keywords:** EGCG (epigallocatechin gallate), dominant bacteria, gallic acid, γ-proteobacteria
