Mutation Breeding Of Nosiheptide Strain And Studis On Its Fermentation And Metabolism

Some research have been done on the properties of Streptomyces actuous which produces nosiheptide, and its isolation and slant media were determined. S.actuosus S-19, isolated from Streptomyces actuous was mutated by various mutagens, and the results indicated that UV and NTG were effective for mutagenesis. After mutating S.actuosus S.actuosus S-19 with UV and NTG alternatively, a stable mutant S.actuosus 9-3-17 was screened out, and the total titer was three times of that the original strain.According to the properties of the mutant S.actuosus 9-3-17,the carbon and nitrogen sources and their contents in the seed and fermentation media were established. The optimum fermentation conditions were determined in the present paper.Some substances related to the biosynthesis of Nosiheptide were investigated on the basis of former researches, NaCl, soybean oil, Mg²⁺, Zn²⁺, Met and Ser can greatly increase the product of Nosiheptide. The results indicated that NaCl was essential for the maintaining osmotic pressure of the cells and enhancing activity of amylase. Soybean oil was involved in the primary metabolism, and could increase PCV, thus it acted as a factor for increasing productivity. Mg²⁺ was activator of many enzymes,Met could promote secondary metabolism and was probably a precursor of Nosiheptide, Ser promotes primary and secondary metabolism simultaneously, all these factors contributed to the increase of the productivity. With the application of TLC, HPLC and mass spectrum, the product was identified to be Nosiheptide.