Characterization of sannamycin A-nonproducing mutants of Streptomyces sannanensis.

Gene cloning in Streptomyces has permitted the identification of a number of antibiotic-biosynthesis genes1 }. Complementation ofnonproducing mutants is commonly used to identify specific antibioticbiosynthesis genes. A serious difficulty is that many antibiotic-producing actinomycetes cannot be transformed efficiently by the conventional methods, e.g., those developed for Streptomyces lividans2). Streptomyces sannanensis IFO 14239 is a case in point. We have examined conditions for protoplasting, regeneration and transformation, to establish a self-cloning system for S. sannanensis3). In the present study, we report the isolation of sannamycin A-nonproducing mutants of S. sannanensis and their classification on the basis of their ability to convert fortimicin A-biosyn-