农抗120生产菌高能电子流诱变育种与发酵性能研究

Studies on Mutagenic Breeding of Agricultural Antibiotic 120 Producing Strain by High Energy Electron Beam and Its Fermentation Characteristics

通过诱变育种提高农抗120生产菌株的发酵效价。采用不同剂量高能电子流辐射孢子芽管悬液、琼脂移块 法初筛、摇瓶管碟法复筛得到高产菌株,然后在发酵罐中放大培养。选育得到一株高产突变株D3226,其摇瓶效价达 9260 μg·mL-1,比出发菌株O11提高了100．4％,并且传代稳定;在100 L和10 t发酵罐中的分批培养实验表明:pH值 下降到最低点5．7时为抗生素累积高峰,pH值可以作为一种新的有效的放罐指标。得到的高产菌株及发酵规律可以应 用于工业生产。

To improve the ferment output of agricultural antibiotics 120 through mutagenic breeding. Spore bud-tube suspension was radiated by high energy electron beam at various dosages. High-yielding mutants were screened by agar block method and shake flask culture. Then the high-yielding mutant was cultured in fed-batch ferment tanks. A high-yielding mutant D3226 with high genetic stability was obtained, and it＇s antibiotic concentration reached 9260μg·mL^-1 on shaker, which was 100. 4% higher than that of original strain Oll. Fermentation test in 100 L and 10-ton tanks showed that the antibiotic level rose to the highest point when the pH value fell to its bottom. Therefore, pH value could be employed as a novel and simple criterion of ferment termination. The stable high-yielding strain and its fermentation traits could be applied to bulk-production.