一款10年陈熟普洱茶中可培养微生物的分离鉴定

在贮存过程中微生物的种类和数量对普洱茶的品质有很大影响。本实验用4种不同的选择性培养基对一款10年陈熟普洱茶中的微生物进行选择性培养和计数；不同的微生物菌落被分离，并用显微镜进行形态观察和初步鉴定，根据细菌的16S rRNA进行分类。结果表明：该款普洱茶的细菌总数为4.3×103CFU/g；霉菌数约为20CFU/g，未发现该普洱茶中存在酵母和放线菌；根据菌落形态分离到的7株细菌都是革兰氏阳性菌，分别属于5个种，即枯草芽孢杆菌(Bacillus subtilis) 2株、解淀粉芽孢杆菌(B. amyloliquefaciens) 1株、地衣芽孢杆菌(B. Licheniformis) 2株、嗜热芽孢杆菌(B. sporothermodurans) 1株和 B. shackletonii 1株；用显微镜进行的形态观察鉴定只分离到两种霉菌，即黑曲霉(Aspergillus niger)和产黄青霉(Penicillium chrysogenum)。

Isolation and Identification of Culturable Microorganisms in a 10-Year-Old Fermented Pu-erh Tea

It has been known that microbial species and quantity have a great influence on the quality of Pu-erh tea during its storage. In this study, four types of selective media were used to culture microorganisms in a 10-year-old fermented Pu-erh tea. The colonies of microorganisms than can grow in each medium were counted. Then, microbial isolation and morphological identification under a microscope were performed. 16S rRNA sequence analysis was used for further identification. The results showed that the total bacterial count in the 10-year-old fermented Puer tea was approximately 4.3 × 103 CFU/g and the mold count was roughly20 CFU/g. Neither yeast nor actinomycete was observed. Seven bacterial strains were isolated and identified as gram-positive bacteria belonging to five species, namely Bacillus subtilis (2 strains), B. amyloliquefaciens (1 strain), B. licheniformis (2 strains), B. sporothermodurans (1 strain) and B. shackletonii (1 strain). Only two mold species such as Aspergillus niger and Penicillium chrysogenum were isolated and identified through microscopic observations.