Dynamics of microbial community during the process of Fu brick tea

Fu brick tea is one kind of fermented dark tea produced in Anhua, Hunan province and characterized the "golden flower" fungus in matured tea. However, dynamics of microbial community during the process and how the “golden flower” formed were remained unclear. This study, totaled 115 tea samples collected from different process stages in 4 factories in Hunan and 1 in Guizhou. Microbes including 305 fungi, 651 yeasts, 288 Streptomyces, 135 bacteria were isolated using series dilution counting method. Details of microbe dynamics during Fu brick tea fermentation process are the highest numbers of microbes were isolated from fresh leaves stage to black rough tea phase. Pleosporales sp., Cladosporium sp., Staphylococcus, Bacillus, Klebsiella, Candida parapsilosis, Debaryomyces sp. and Streptomyces sp. are frequently encountered. However, species of Penicillium, Aspergillus, Bacillus, and Cyberlindnera rhodanensis become more abundant before the compressed bricks. While “golden flower” fungi Eurotium amsterdam and Eurotium cristatum developed were extremely dominant fungi during the fermentation of bricks and the species of Penicillium, Aspergillus, yeast, bacteria, actinomycetes were almost not detected. Detection of the “golden flower” fungus by real-time quantitative PCR indicated that it occurs in all fermentation stages but is quite few in the early stages and sharply increases during brick fermentation. Observation with scan electron microscope showed that conidia of golden flower fungus occurred in the early stage of Brick fermentation and quite large numbers of cleistothecia formed in the late stages. The dynamics of microbial community also investigated by pyrosequencing and the data is undergoing annotation and analysis.