[Leukaemomycin-blocked mutants of Streptomyces griseus and their pigments].

In a continued search for leukaemomycin-blocked mutants of three leukaemomycin-producing strains IMET JA 3933, IMET JA 5142 and IMET JA 5570 of Streptomyces griseus, 32 mutants producing aerial mycelium and spores were detected. Furthermore, in all mutants cosynthetic capability has been observed. This report describes characterization of leukaemomycin-blocked mutants obtained by mutagenic treatment experiments using NTG and combined UV-/X-rays. According to the biosynthetic capability for anthracyclinones or other pigments the mutants could be divided into six classes. The first class contains 14 leukaemomycin-blocked mutants unable to synthesize anthracyclinones. Besides two classes of mutants (12)synthesizing well-known anthracyclinones as epsilon-rhodomycinone, 7-deoxy-epsilon-rhodomycinone, 11-deoxy-derivatives of daunomycinone, three new classes of mutants (6) synthesizing reddish-brown, brown and blue-violet pigments on solid media with structures not elucidated as yet, will be described.