Journal of Tea Science Research, 2024, Vol.14, No.2, 92-101 http://hortherbpublisher.com/index.php/jtsr 96 closely linked to the development of unique flavors. For instance, the presence of Aspergillus in the early stages and other genera like Bacillus and Rasamsoniain later stages contribute to the formation of key flavor compounds. Similarly, in kombucha tea, the interaction between bacteria such as Komagataeibacter rhaeticus and yeast like Brettanomyces bruxellensis is crucial for biofilm production and flavor development. The metabolic activities of these microbes, including the fermentation of sucrose and production of key metabolites, shape the sensory characteristics of kombucha (Landis et al., 2022). These findings underscore the importance of microbial diversity in determining the flavor attributes of fermented teas (Zhao et al., 2019). 4.3 Case study: Health implications of microbial interactions The health benefits of fermented teas are closely linked to the interactions within their microbial communities. For example, Pu'er tea has been shown to alter the gut microbiota composition and function in diet-induced obese rats, promoting microbial diversity and beneficial metabolic processes. The administration of Pu'er tea extracts increased the relative abundances of Firmicutes and decreased Bacteroidetes, enhancing community metabolic processes such as sucrose metabolism and glycolysis (Xia et al., 2019). These changes are associated with the prebiotic effects of Pu'er tea, potentially promoting the growth of beneficial bacteria like Akkermansia muciniphila. Additionally, the microbial interactions in kombucha tea, particularly between bacteria and yeast, contribute to the production of bioactive compounds that may have health-promoting properties. These studies highlight the potential health benefits of microbial interactions in fermented teas. 5 Functional Analysis of Microbial Communities 5.1 Functional roles of dominant microbes The functional roles of dominant microbes in tea fermentation are diverse and critical for the development of the unique flavors and qualities of fermented teas. In Pu-erh tea fermentation, Aspergillus species are identified as the primary flavor-producing microorganisms during the early stages of solid-state fermentation (SSF), contributing to the formation of key flavor compounds such as theabrownin and methoxy-phenolic compounds (Li et al., 2018). Similarly, in the SSF of Pu-erh tea, Aspergillus is the dominant fungus and a major host of identified proteins, including enzymes involved in the degradation of plant cell walls and the oxidation of catechins (Zhao et al., 2015). In Fuzhuan brick tea, bacterial communities, particularly Lactococcus and Bacillus, play significant roles in the metabolic processes, correlating with the production of various metabolites (Xia et al., 2021). Additionally, in kombucha tea, the bacterium Komagataeibacter rhaeticus and the yeast Brettanomyces bruxellensis are the most common microbes, with B. bruxellensis enhancing biofilm formation and fermentation qualities (Landis et al., 2022). 5.2 Metabolic pathways involved in tea fermentation The metabolic pathways involved in tea fermentation are complex and involve various microbial interactions. In Pu-erh tea, the formation pathways of dominant flavors such as theabrownin, methoxy-phenolic compounds, alcohol, and carvone have been proposed, highlighting the intricate metabolic processes driven by microbial communities (Hu et al., 2020). The integration of metagenomics and metaproteomics in Pu-erh tea fermentation has revealed enzymes associated with the degradation of plant cell walls and the oxidation of catechins, further elucidating the metabolic pathways involved. In Fuzhuan brick tea, predictive metabolic functions indicate pathways related to cellular growth, environmental information processing, genetics, and material metabolism, with significant correlations between bacterial populations and metabolites. Additionally, in kombucha tea, the enhanced ability of B. bruxellensis to ferment and produce key metabolites in sucrose-sweetened tea is linked to its role in stimulating biofilm formation (Landis et al., 2022). 5.3 Bioinformatics tools for functional prediction Bioinformatics tools play a crucial role in predicting the functional properties of microbial communities in tea fermentation. Shotgun metagenomic sequencing and metabolomic analysis are employed to reveal the composition and functional genes of microbiota in Pu-erh tea fermentation, providing insights into the association between microbiota and tea quality. Metaproteomics analysis, combined with metagenomics, is used to identify
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