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Inactivation of putative PKS genes can double geldanamycin yield in Streptomyces hygroscopicus 17997

Author(s): Y.H. Li, M. Li, W.Q. He, Y.G. Wang and R.G. Shao

The putative polyketide biosynthesis (PKS) genes cos10 and pg10 were inactivated by insertion of a kanamycin-resistance gene into the genome of the geldanamycin-producing strain, Streptomyces hygroscopicus 17997. The resultant inactivation were confirmed by PCR analysis. The abilities of the PKS gene inactivation strains to produce geldanamycin were compared with the natural geldanamycin- producing strain, S. hygroscopicus 17997. The cos10-inactivated strain exhibited an unchanged ability to produce geldanamycin, but the pg10- inactivated strain can produce twice the yield of the natural strain when grown under the same conditions. We propose that there is a sub-PKS pathway in the geldanamycin-producing strain, S. hygroscopicus 17997.