后发酵茶中短短芽孢杆菌产酶能力及其在茶叶渥堆过程酶活性分析

Enzyme production capacity of Brevibacillus brevis in post-fermented tea and its enzyme activity in the process of pile-fermentation

中文关键词:  短短芽孢杆菌  后发酵茶  基因组测序  酶活性  理化成分

英文关键词:Brevibacillus brevis  post-fermented tea  genome sequencing  enzyme activity  physicochemical components

中文摘要:

      目的 全面了解源自后发酵茶中短短芽孢杆菌(Brevibacillus brevis, Br. brevis)的产酶特性, 揭示其对后发酵茶品质形成的作用。方法 对短短芽孢杆菌进行全基因组测序和关键酶预测, 结合预测结果对短短芽孢杆菌进行纯培养、接种茶叶渥堆, 分析其纯培养和参与茶叶渥堆过程的产酶能力、酶活性及渥堆茶叶主要品质成分的动态变化。结果 测序结果表明短短芽孢杆菌糖苷水解酶、糖基转移酶得到注释基因最多, 分别占比39.22%和33.33%。在短短芽孢杆菌的纯培养和参与茶叶渥堆过程中, 短短芽孢杆菌具有产生蛋白酶、淀粉酶、果胶酶、纤维素酶、过氧化物酶和多酚氧化酶的能力, 其中蛋白酶、淀粉酶和果胶酶活性较强, 纯培养条件下蛋白酶酶活力最高可达到550.91 U/mL; 相较于液体纯培养, 在茶叶基质上培养有助于短短芽孢杆菌纤维素酶酶活力的提高, 增幅达到691.02%; 在短短芽孢杆菌参与的茶叶渥堆过程中, 茶多酚、儿茶素、氨基酸和黄酮呈现下降趋势, 茶多酚最大降幅为80.61%, 咖啡碱检测含量显著增加, 增幅最大为56.15%; 相关性分析结果表明, 渥堆过程短短芽孢杆菌产生的纤维素酶等与茶叶品质成分的变化表现出显著的正相关。结论 短短芽孢杆菌在后发酵茶渥堆过程可以分泌多种胞外酶, 通过酶促作用影响后发酵茶理化成分的改变。

英文摘要:

      Objective To investigate the enzyme-producing characteristics of Brevibacillus brevis (Br. brevis) from post-fermented tea and reveal its effect on the quality formation of post-fermented tea. Methods The whole genome of Br. brevis was sequenced and the key enzymes were predicted. Combined with the predicted results, the ability to produce enzyme, enzymatic activities and the dynamic change of tea quality components were analyzed during pure culture and inoculation of tea. Results The sequencing results showed that the most annotated genes were glycoside hydrolase and glycosyltransferase, which accounted for 39.22% and 33.33% respectively. In the process of pure culture and participation in tea pile-fermentation. Br. brevis had the ability to produce protease, amylase, pectinase, cellulase, peroxidase and polyphenol oxidase. The activities of protease, amylase and pectinase were stronger, and the highest activity of protease was 550.91 U/mL under pure culture condition. The activity of Br. brevis cellulase was increased by 691.02% when cultured on tea substrate. In the process of tea pile-fermentation with the participation of Br. brevis, tea polyphenols, catechins, amino acids and flavonoids showed a decreasing trend, the maximum decrease of tea polyphenols was 80.61%, and the content of caffeine was significantly increase, with the maximum increase of 56.15%. The results of correlation analysis showed that the cellulase produced by Br. brevis during pile-fermentation process had a significant positive correlation with the changes of tea quality components. Conclusion During pile-fermentation process of the post-fermented tea, Br. brevis can secrete a variety of extracellular enzymes, which can affect the changes of physical and chemical components of post-fermented tea through enzymatic action.