本文探讨微波诱变对新一代必特螺旋霉素基因工程菌的育种效果.以经紫外诱变筛选的新一代必特螺旋霉素产生菌Streptomyces spiramyceticus NBT-U149为出发菌株进行微波诱变筛选.辐射分四种方式:培养皿加盖冷却;加盖不冷却;不加盖冷却;不加盖不冷却,辐射时间分别为10、20、30、40、50、60、80、100和120s.每次辐射5s后,冰上快速冷却20s再照射,并将照射时间累计.以不同的辐射时间设定为不同的微波处理剂量,计算致死率.结果 表明,必特菌株对微波敏感,微波辐射60s时致死率达到92.55%.微波诱变在以脉冲频率为2450MHz的800W家用微波炉条件下,其最佳作用方式为培养皿不加盖、冰上快速冷却,最佳辐射时间为50s.初筛摇瓶正突变率达到57.14%,复筛摇瓶发酵效价是出发菌株1.6倍以上的有10株,占初筛菌株的2%.最终筛选得到突变株Streptomyces spiramyceticus NBT-UM22,其必特螺旋霉素发酵产量是出发菌株的1.87倍,且组分比例无明显变化.%The microwave radiation effect on breeding of new genetically engineered strain of bitespiramycin was explored. Radiation was carried in four ways: covered with or without cooling;uncovered with or without cooling. Radiation time was setting at 10,20,30,40,50,60,80,100 and 120s interval. The rapid cooling was applied for 20s on ice after each 5s radiation and the radiation time was accumulated. Different radiation time was considered as the difference in radiation dose of microwave treatment and mortality rates were calculated . Experimental results indicated that the newly generated bitespiramycin producing strain NBT-U149 was sensitive to microwave radiation, the mortality of the spores was reached to 92.55% after 60s radiation. At 2450MHz frequency 800W microwave spore suspention was placed in uncovered dish plate and quick-cooling after radiation was applied as the optimal radiation mode for microwave radiation, and 50s was considered as the optimal radiation time of microwave treatment, Under this circumstances, the positive mutation rate was 57.14% in the prelimenary screening. Ten strains of producing bitespiramycin in a yield of 1.6 times higher than that of the parent strain were obtained, which consisted of 2% in the prelimenary screening. A stable high producing Streptomyces strain NBT-UM22 was isolated. Its bitespiramycin fermentation titer in the shaking flask increased by 1.87 times higher than the parent strain without significant changes in the constituent proportion of the components.
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