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| Diversity of the Bacillus-like Species in the Different Year-old Fermented Pu-erh Tea |
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Abstract Abtract Microbial activity plays very important roles in the formation of the characteristics and quality of Pu-erh tea. Among these microorganism, Bacillus-like species are the dominant group at the late fermentation stage of Pu-erh tea. The present paper reported the distribution and diversity of Bacillus-like species in the different year-old fermented Pu-erh tea. Sixteen Pu-erh tea samples, including Longma Tongqinghao tea, Dayouqing tea and Junyixiang tea, were collected for the investigation. These tea samples were produced by sun-dried green tea leaves of big-leaf species of tea trees (Camellia sinensis) in the certain regions of Yunnan province at different years. The Bacillus-like strains in the samples were isolated by dilution plate method and were preliminarily identified by 16S rRNA gene sequencing analysis. The results showed that 153 Bacillus-like strains were isolated and were classified into 8 genera, 36 species. Among these strains, Bacillus were the most dominate genera (with a number of 20 Bacillus-like species and 87 strains) and was followed by the genera Lysinibacillus (6 species, 20 strains) and Brevibacillus (4 species, 20 strains). The other 5 genus were Fictibacillus, Oceanobacillus, Ornithinibacillus, Paenibacillus and Virgibacillus. Fictibacillus and Ornithinibacillus were first reported and isolating from the fermented Pu-erh tea. Generally, Bacillus-like species and quantities were different in the different tea samples. The numbers of Bacillus-like strain and quantity isolated from the Zhongcha (Hongyin Lvzi) tea were maximum, which were 19 and 3.76×105 cfu/g, respectively. There were 12 Bacillus-like species colonizing in the Wenge Chazhuang (Hongqi Gongshe) tea, which was the most among these tea samples. The quantity of Bacillus-like isolated from the Jingchanghao tea was minimum, which was 7.62×103 cfu/g. The distributions of different Bacillus-like species in these 16 tea samples were different. Ba. cereus and Ba. shackletonii were isolated from 9 tea samples and were the most ubiquitous species. Ba. oleronius was secondly ubiquitous, which was isolated from 8 tea samples. The quantities of the same Bacillus-like species colonizing in different tea samples were different, and the quantities of different Bacillus-like species colonizing in the same tea sample were also different. In conclusion, the results indicated that the Bacillus-like community colonized in the different year-old fermented Pu-erh tea was abundant, but there were differences of Bacillus-like species and quantity among these Pu-erh tea samples. These results may provide material and theoretical reference for exploring the action mechanism of Bacillus-like species on the characteristics of Pu-erh tea, the correlation between Bacillus-like species and the health functions of Pu-erh tea.
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Received: 18 January 2017
Published: 20 July 2017
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