Study On The Breeding Of Production Strains And Fermentation Of Avermectins Bjbm0006

The gene replacement strain Bjbm0006, which no longer produce the avermectin A.A stable mutated strain was obtained from the spores of avermectin producer streptomyces avermitilis Bjbm0006 by purification. The spores of f-218 were mutated by Streptomycin resistant rational screening, Erythromycin resistant rational screening, LiCl-UV, ~60Co-γ irradiation, electroporation, shuffling. The results showed that, ~60Co-γ irradiation, electroporation, shuffling could enhance the fermentation ability of strains. Subculture test indicated that z-27 had relatively stable hereditary characteristics than others. The chemical titer of the z-27 were increased by 167.19% compared with its parent strains.On shaking flask level, the fermentation media was examined with Z-27. Based on primary media, the effect of carbon, nitron, bean oil to fermentation were investigated. We also screened the optional level of every component of the fermentation media by orthogonal experiments. And an optimum fermentation medium was found.Experiment determining the sample contents, pH before sterilized and temperature of z-27 fermentation showed that the optional conditions were the volume 20ml/150ml,pH7.6 before sterilized, temperature 28℃.