[Obtaining of mutants of Streptomyces fradiae producing tylosin by action of nitrosomethylurea on synchronously germinating spores].

The method of localized mutagenesis was applied to obtain mutants of Streptomyces fradiae producing higher amounts of tylosin. The populations of the germinating spores were subjected to a short-term treatment with nitrosomethylurea during different periods of the first DNA replication cycle. The method reveals defines periods sensitive to mutation induction and isolates a mutant producing a 60% increase in the yield of tylosin as compared to that provided by the stock strain.