## 1 Introduction  
Post-fermented Pu-erh tea (Pu-erh Shucha, PFPT) is a well-known traditional Chinese tea with special sensory characteristics including mellow taste, stable flavor, and brownish-red color [1]. Additional, in vivo, in vitro, and clinical studies have suggested that PFPT has multiple health benefits, such as hypolipidemic, antiobesity, antimutagenic, antioxidative, antitumor, free radical scavenging, and toxicity-suppressing activity [2]. As a healthy beverage, it is popular in Southeast Asia and has also been introduced to the Western marketplace in recent years.  
Unlike the raw material of black tea, fresh tea leaves [3; 4], the raw materials of PFPT are sun-dried green tea (a variety of green tea products) produced from _Camellia sinensis_ var. _assamica_ ([PERSON]) Kitamura [5]. In PFPT manufacturing, the post-fermentation process is crucial. In this process, the sun-dried tea leaves are stacked for a few weeks, leading to a series of oxidation, condensation, and degradation reactions in the chemical constituents of the tea [6]. From the microbiological view, the post-fermentation of PEPT is a solid-state fermentation (SSF). Unlike the chemical changes of black tea in fermentation, which are catalyzed by endogenous enzymes in tea leaves [3,4], the chemical changes in the SSF of PEPT are catalyzed by the microbial enzymes [1]. Presently, the SSF of PEPT is a natural fermentation without the use of starter cultures or the sterilization of raw materials. This gives rise to the growth of diverse microorganisms that may be primarily involved in the development of the different tastes, flavors, and health benefits of PEPT. Therefore an in-depth knowledge of the diversity and dynamics of the microbiota and changes in tea compounds in the SSF of PEPT is essential to understanding the formation of the characteristic properties of PEPT, and to develop industrial starters and control systems.  
The diversity of microbiota in SSF was investigated by culture methods and many microbial species belonging to a variety of families have been identified, such as Aspergillusaceae, Bacillaceae, Chaetomiaceae, etc. [7]. Additionally, a high level of microbiota diversity was gained using culture-independent approaches, such as denaturing gradient gel electrophoresis (PCR-DGGE) [8, 9, 10, 11], a _165 rRNA_ gene clonal library [7], and pyrosequencing analyses [12,13]. Recently, we investigated the microbial communities and enzymes of an SSF processing sample of PEPT (collected on day 21) using 454 pyrosequencing and LC-MS/MS approaches [13]. The microbiome and 25 toxic metabolites in fermented Pu-erh tea were investigated by Illumina MiSeq platform (Illumina, Inc., SanDiego, CA, USA) and a quantitative multiplex metabolite analysis [14]. However, the dynamics of the microbiota in SSF had only investigated by PCR-DGGE [8,10,11] and a _165 rRNA_ gene clonal library [7]. Thus, further studies using Next-Generation Sequencing were necessary. Additionally, several reports, such as those by [PERSON] [15], [PERSON] [16], and [PERSON] [17], evaluated the changes in the chemical compounds during the SSF of PEPT. None of these studies established the influence of the successive microbial populations on the changes in the tea's chemical components during the SSF of PEPT.  
In this work, the microbial succession and dynamics of the tea's characteristic chemical compounds in the SSF of PEPT were studied, and the relationship between microbiota and changes in tea compounds was surveyed. This research provides a foundation for further comprehensive studies on the formation of the special properties of PEPT and for the development of industrial starters.