Cold Tea Fermentation Bacteria, Mutation Breeding And Fermentation Conditions Optimization Study

The strain SW3 was screened which could produce cellulase, and the tea could make by the cold water that was fermented by SW3 and was manufactured by a certain processing technology. But the activity of cellulase of SW3 was lower, and the effect of making tea of the tea of fermented by SW3 was worse by the cold water than by the hot water. The purpose of the present study was to mutagenesis the strain SW3, and to screen the strain that the activity of cellulase was higher, and the optimal fermentation conditions of a mutant strain were studied and the tea was fermented by the mutant strain and a trichoderma green which was conserved in the food microorganism laboratory of our food college, to improve the ability of the tea of making tea in the cold water.This paper included: (1) the strain SW3 was treated by UV ,NaNO₂ and UV+ NaNO₂ for the mutants with high cellulase activity; (2) culture medium optimization for producing cellulase by SW355 ;(3) The research of character of the cold-making tea. The main results were as follows:1 Based on the SW3, the mutant strain SW302 was obtained through treatments of UV .The strain isolation was divided into two phases. First isolation was according to the method of distinct zone of clearing in Cellulose-Congo red agar medium. Second isolation was according to the test of filter paper enzyme activity through liquid fermentation. The filter paper enzyme activity of the mutant strain SW302 was 37.3% higher than the original strain SW3.2 Based on the SW3, no mutant strain that the filter paper enzyme activity of the mutant strain was 30% higher than the original strain SW3 was obtained through treatments of NaNO₂ .The strain isolation was divided into two phases. First isolation was according to the method of distinct zone of clearing in Cellulose-Congo red agar medium. Second isolation was according to the test of filter paper enzyme activity through liquid fermentation.3 Based on the SW3, two mutant strains of SW350 and SW355 that the filter paper enzyme activity of the mutant strain was 30% higher than the original strain SW3 were obtained through treatments of UV+ NaNO₂ .The strain isolation was divided into two phases. First isolation was according to the method of distinct zone of clearing in Cellulose-Congo red agar medium. Second isolation was according to the test of filter paper enzyme activity through liquid fermentation. The filter paper enzyme activity of the mutant strain SW350 and SW355 was 36.4% and 62.9% higher than the original strain SW3.4 Through the experiment of genetic stability, it was found that the mutant strain SW302 and SW355 had both stably passed on five generations and the mutant strain SW350 had not. Considering the filter paper enzyme activity of the mutant strain SW355, the mutant SW355 was selected for the next experiments.5 Compared the original strain SW3 with the mutant SW355 in Cellulose-Congo red agar medium, the mutant SW355 was smaller and grew slower, and the spores of the mutant SW355 had fewer than the original strain SW3, and the color of spore of the mutant SW355 was light green, but the color of spore of the original strain SW3 was green, and the ratio of the hydrolysis circle...