【摘要】 设计了几组不同的诱变条件对γ多聚谷氨酸生产菌BacilluslicheniformisATCC9945A进行诱变,诱变后将所有菌株混合,以此未经筛选的混合菌共同发酵,并以终产量为指标对发酵条件进行连续的定向调控,使发酵条件逐渐向高产正突变株倾斜,产量得以逐步提高.同时在混合菌状态下找到适合高产正突变株的发酵条件,以此发酵条件作为筛选平板,对混合菌分离纯化,选育到γPGA高产菌Zγ29,产量是出发菌株的4.14倍,筛选条件即为该突变株的最佳发酵条件.更多还原

【Abstract】 Mutation breeding is one of the effective methods to obtain mutant with better character. It’s ineffective and difficult to obtain the target mutant in traditional way. The author has proposed a novel technique which can improve the efficiency of breeding work, and designed several mutation conditions to treat Bacillus licheniformis ATCC 9945A, which can produce γ-PGA, and mixed all the mutant strains after treatment. As fermenting this unscreened mixture of mutant strains, and optimizing the fermentative process according to the yield of γ-PGA, the condition tend to fit for the positive strain, and the yield of γ-PGA increased. On the mix-strains situation, meanwhile, the best fermentative process for the positive strain which has the higher yield of γ-PGA was found, and then it was used as the selection plate to separate and purify the mix-strains. In this way a strain Zγ-29 had been quickly and effectively bred from only 40 individual strains, of which the yield has increased 4.14 times than the 4.582g/L of original strain. And the optimized fermentative process for that strain has also been found out. The result shows a novel idea can obtain mutant strain with good characters effectively, which may lay forth a new way for other microbe’s mutation breeding work.更多还原