| 【Objective】Aspergillus and Eurotium are the dominant microorganisms in the pile fermentation of
Chinese dark tea, and play a key role in the formation of different flavors, qualities and physiological functions of dark tea.
However, the differences in these fungal hydrolases during tea fermentation are still unclear. 【Method】The difference
of extracellular hydrolase activity between different strains of Aspergillus and Eurotium in the synthetic medium and tea
fermentation conditions was analyzed by combining differential medium plate assay and enzyme activity assay. 【Result】
The results of differential medium plate assay showed that: Nine strains tested showed cellulose, xylanase and tannase
activities to different extent; seven strains showed amylase activity, two strains showed pectinase activity, and one strain
showed protease activity. The same strain could secrete a variety of extracellular hydrolases at the same time, and multiple
strains could also show the activity of the same hydrolase. The ability of different strains to produce extracellular hydrolase was significantly different. During the fermentation of tea , the enzymatic activity of Aspergillus niger strain PE-3 hydrolyzed
macromolecular carbohydrates was significantly higher than that of Eurotium cristatus strain PE-1,with the amylase activity
of strain PE-3 at 33.81 U/mL. While the tannase and protease activities of strain PE-1 were significantly higher than those of
strain PE-3,with the tannase activity at 132.09 U/mL. 【Conclusion】 During the fermentation of tea, the strains of Aspergillus
and Eurotium might have selectivity for different tea components, and the synergistic effect of hydrolases had an impact on the
utilization efficiency of the tea components. |
