Division of Biotechnology, School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai, 50100, Thailand.
Division of Food Science and Technology, School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai, 50100, Thailand.
J Microbiol. 2017 Sep;55(9):720-729. doi: 10.1007/s12275-017-7195-8. Epub 2017 Sep 2.
The microbiota of lactic acid bacteria (LAB) in thirty-five samples of Miang, a traditional fermented tea leaf product, collected from twenty-two different regions of eight provinces in upper northern Thailand was revealed through the culture-dependent technique. A total of 311 presumptive LAB strains were isolated and subjected to clustering analysis based on repetitive genomic element-PCR (rep-PCR) fingerprinting profiles. The majority of the strains belonged to the Lactobacillus genera with an overwhelming predominance of the Lb. plantarum group. Further studies of species-specific PCR showed that 201 of 252 isolates in the Lb. plantarum group were Lb. plantarum which were thus considered as the predominant LAB in Miang, while the other 51 isolates belonged to Lb. pentosus. In contrast to Lb. plantarum, there is a lack of information on the tannase gene and the tea tannin-tolerant ability of Lb. pentosus. Of the 51 Lb. pentosus isolates, 33 were found to harbor the genes encoding tannase and shared 93-99% amino acid identity with tannase obtained from Lb. pentosus ATCC 8041. Among 33 tannase gene-positive isolates, 23 isolates exhibited high tannin- tolerant capabilities when cultivated on de Man Rogosa and Sharpe agar-containing bromocresol purple (0.02 g/L, MRS-BCP) supplemented with 20% (v/v) crude tea extract, which corresponded to 2.5% (w/v) tannins. These Lb. pentosus isolates with high tannin-tolerant capacity are expected to be the high potential strains for functional tannase production involved in Miang fermentation as they will bring about certain benefits and could be used to improve the fermentation of tea products.
采用传统培养技术，揭示了泰国北部上地区 8 省 22 个不同地区采集的 35 份米安（一种传统发酵茶叶产品）中乳酸菌（LAB）的微生物群。共分离出 311 株疑似 LAB 菌株，并根据重复基因组元件-PCR（rep-PCR）指纹图谱进行聚类分析。大多数菌株属于乳杆菌属，其中以 Lb. plantarum 组为主导。进一步的种特异性 PCR 研究表明，Lb. plantarum 组中的 252 个分离株中有 201 个为 Lb. plantarum，因此被认为是米安中的主要 LAB，而其他 51 个分离株属于 Lb. pentosus。与 Lb. plantarum 不同，关于 Lb. pentosus 的单宁酶基因和茶单宁耐受能力的信息较少。在 51 株 Lb. pentosus 分离株中，有 33 株携带编码单宁酶的基因，与从 Lb. pentosus ATCC 8041 获得的单宁酶共享 93-99%的氨基酸同一性。在 33 株单宁酶阳性分离株中，有 23 株在含有 0.02 g/L 溴甲酚紫（MRS-BCP）的改良 Man-Rogosa 和 Sharpe 琼脂上培养时表现出较高的单宁耐受能力，并用 20%（v/v）粗茶提取物补充，相当于 2.5%（w/v）的单宁。这些具有高单宁耐受能力的 Lb. pentosus 分离株有望成为米安发酵中功能性单宁酶生产的高潜力菌株，因为它们将带来一定的好处，并可用于改善茶产品的发酵。
