Metabolic Engineering Transform S.Ambofaciens To Optimize The Fermentation Component Of Spiramycin

Streptomyces ambofaciens synthesizes the macrolide antibiotic spiramycin. Most of the spiramycin biosynthetic gene sequence has been sequenced. By the gene sequence comparison, we found two genes orf1and orf31that may code epoxidation modifying enzymes; two genes orf1*c and orf9c that may code N-dimethy1transferase.In this study, We identified the resistance Streptomyces ambofaciens has, We constructed and optimized the Escherichia coli-Streptomyces ambofaciens inter-species conjugation system. Screening and get spiramycin biosynthesis gene library. We get gene duplication mutants:S.pSET-orfl, S.pSET-orf1*c and S.pSET-orf31, S.pSET-orf1*c and S.pSET-orf31weakened the ability that produce Impurities which m/z is875. S.pSET-orf1reducing the capacity of producte spiramycin. we get the knockout mutants:L-D1, L-D1*c, L-D9c and L-D31.L-D9c produce Intermediate metabolites which m/z is815. The other three knockout mutation is basically lost the capacity of producing spiramycin and related intermediate metabolites.