一株抗生素产生菌No.24菌株发酵液抗菌谱及稳定性测定研究

Studies of antagonistic spectrum and stability of fermentation of No. 24 strain producing one antibiotic

从12个省采集的200份土壤中分离得到一株放线菌No．24菌株，其产生菌经初步鉴定为链霉菌属(Streptomyces)。以17种病原真菌、8种病原细菌和酵母菌为供试菌，分别采用抑制菌丝生长速率法和管碟法测定了No．24菌株发酵液对病菌的抗菌活性。抑制菌丝生长速率法生测结果表明，No．24菌株发酵液对17种供试真菌的菌丝生长抑制率达80％以上的占76．5％；管碟法生测结果表明，No．24菌株发酵液对8种供试细菌和酵母菌的4种抑菌圈直径在15mm以上。对No．24菌株发酵液的稳定性测定结果表明，发酵液对热和酸的稳定性强，发酵液加热到80C未丧失活性，在pH2～3的1mol／LHcl溶液中活性几乎不丧失，但对碱的稳定性差。菌株传接5代时，活性稳定，从第6代开始其活性缓慢降低，第10代的抑菌圈直径比出发菌株仅减少了1．8mm。

The strain of No. 24 was isolated from the soil of 200 samples collected in 12 provinces of China. By identification, the strain was regarded as streptomyces, taking 17 epiphyte, 8 bacteria and mi crozyme as object, fungicidal activity of bioassey was studied. By means of mycelium growth rate, the results showed that the fermentation products of No. 24 had 80% control effects (76. 5% of the total). By means of agar diffusion method,the test exhibited that the antagonistic diameter reached more than 15mm to 4 bacteria of 8,. through the research of stability of the fermentation products of No. 24 to heat ,acid ,and alkali,the fermentation of No. 24 had a high activity to epiphyte, bacteria and microzyme at 80 C ,but it is less stable to alkali. When it was subcultured for 5 generations, its stability was steadiness. Subcultured from the 6th generation to the 10th generation,its stability was slowly failed,the inhibitory diameter of the 10th generation decreased only 1. 8mm compared with original strain.