原生质体诱变选育去甲基金霉素高产菌

采用紫外线、同平板梯度浓度亚硝基肌，纯铜蒸气激光诱变去甲基金霉素生产菌金霉素链霉菌的原生质体，结果表明原生质体对各种诱变剂的敏感性较高.正变幅度较大.原生质体经紫外线、同平板梯度浓度亚硝墓肌复合诱变后，筛选到一菌株，重新制备原生体，经激光诱变，选育出高产菌株S. A. HU02，去甲基金霉素效价从2831u/ml提高到4337u/ml，提高了53. 2，经多次传代产量性状非常稳定.

Selection of High-Yielding Demethylchlorotetracycline Mutant Strain Using Protoplast Mutagenesis

Protoplasts of the demethylchlorotetracycline producing strain Slrrptoncyces uurrufucirns weretreated by ultraviolet,NTG in gradient plate and single-copper-vapour laser. The results showed that af-ter the treatments the protoplasts were susceptible to various mutagenic agents,and had a larger rangein positive mutation. After combine using of the UV and NTG in gradient plate treatment，a mutantstrain was selected. The protoplasts,were isolated.recovered from the resulting strain,and were mutat-ed by laser of S. A. HU402. The titer of demethylchlorotetracycline into a high-yielding strain was in-creased from 2831 a/ml upto 4337 a/ml. The incereasing rate was 53. 200. The yield was very stablethrough many generations.