Unban Kridsada, Khatthongngam Nuttapong, Pattananandecha Thanawat, Saenjum Chalermpong, Shetty Kalidas, Khanongnuch Chartchai
Division of Biotechnology, School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, Chiang Mai, Thailand.
Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, Thailand.
Front Microbiol. 2020 Jul 14;11:1515. doi: 10.3389/fmicb.2020.01515. eCollection 2020.
, a traditional fermented tea leaf ( var. ) consumed in northern Thailand, was simulated in laboratory conditions using non-filamentous fungi process (NFP) and microbial community was periodically investigated for over 6 months of fermentation by both culture-dependent and -independent techniques. The viable cell numbers of lactic acid bacteria (LAB), yeast, and enumerated by the culture-dependent technique markedly surged over 3 days of initial fermentation and then smoothly declined by the end of fermentation. LAB were found as the main microbial population throughout the fermentation period followed by yeast and . High-throughput sequencing of microbial community during fermentation revealed that (86.9-96.0%) and (4.0-12.4%) were the dominant bacterial phyla, whereas was found to be the main fungal phylum with an abundance of over 99% in the fungal community. The dominant bacterial family was (39.7-79.5%) followed by , , , , , , , , , and . Meanwhile, the main fungal family was (75.6-90.5%) followed by , , , , , and . In addition, (29.2-77.2%) and (3.8-22.8%), and the unicellular fungi, (72.5-89.0%) and (8.1-14.9%), were the predominant genera during the fermentation process. The profiles of physical and chemical properties such as texture, pH, organic acids, polysaccharide-degrading enzyme activities, and bioactive compounds have rationally indicated the microbial fermentation involvement. β-Mannanase and pectinase were assumed to be the key microbial enzymes involved in the fermentation process. Total tannin and total polyphenol contents were relatively proportional to the antioxidant activity. Lactic acid and butyric acid reached maximum of 50.9 and 48.9 mg/g dry weight (dw) at 9 and 63 days of fermentation, respectively. This study provided essential information for deeper understanding of the fermentation process based on the chemical and biological changes during production.
泰国北部消费的一种传统发酵茶叶（ 变种 ），在实验室条件下使用非丝状真菌工艺（NFP）进行模拟，并通过依赖培养和不依赖培养的技术，对长达6个多月的发酵过程中的微生物群落进行定期研究。通过依赖培养的技术计数的乳酸菌（LAB）、酵母和 的活菌数在初始发酵的3天内显著激增，然后在发酵结束时平稳下降。在整个发酵期间，LAB被发现是主要的微生物种群，其次是酵母和 。发酵过程中微生物群落的高通量测序显示， （86.9 - 96.0%）和 （4.0 - 12.4%）是主要的细菌门，而 被发现是主要的真菌门，在真菌群落中的丰度超过99%。主要的细菌科是 （39.7 - 79.5%），其次是 、 、 、 、 、 、 、 、 、 。同时，主要的真菌科是 （75.6 - 90.5%），其次是 、 、 、 、 。此外， （29.2 - 77.2%）和 （3.8 - 22.8%），以及单细胞真菌 （72.5 - 89.0%）和 （8.1 - 14.9%）是发酵过程中的主要属。诸如 质地、pH、有机酸、多糖降解酶活性和生物活性化合物等物理和化学性质的概况合理地表明了微生物发酵的参与。β-甘露聚糖酶和果胶酶被认为是参与 发酵过程的关键微生物酶。总单宁和总多酚含量与抗氧化活性相对成比例。乳酸和丁酸分别在发酵的第9天和第63天达到最大值，分别为50.9和48.9 mg/g干重（dw）。这项研究基于生产过程中的化学和生物学变化，为更深入了解 发酵过程提供了重要信息。
