The Studies On The Nosiheptide-producing Strain Of Streptomyces Actuosus

In order to improve the productivity of nosiheptide for the industrial need, the methods of strain improving of Streptomyces actuosus 4-1 and the fermentation media were studied in this paper..First, the strain N-26 ,which was a high-yield and stable strain with a high productivity, was obtained by a procedure of natural screening. Investigation of different mutagen and different dosage of each kind of mutagen lead to the confirmation of a suitable mutagenesis condition-HNO_2,45min. which is suitiable for obtaining mutants with a higher productivity.Secondly, the screening models of tolerance to streptomycin, kanamycin and nosiheptide were established. Results showed that the probability of obtaining high-yield strain increased obviously: the high-yield strain K-35-65 with a fermentation titer of 2566μg/ml and strain S-92 with a fermentation titer of 2780μg/ml were obtained.The fermentation media were also inspected in this paper . The optimal nitrogen source is soybean and peanut meal through the study . Fermentation medium of nosiheptide was optimized through orthogonal design . The inspecting test of inorganic salt and trace element had shown that suitable amount of MgSO₄-7H₂O, Na₂S₂O₃, Co²⁺ and Fe²⁺ were able to increase the production of nosiheptide.