THE ANTIBIOTIC YA-56 COMPLEX: TAXONOMY AND PRODUCTION OF THE PRODUCING STRAIN

A new complex of phleomycin-bleomycin group antibiotics, YA-56, was isolated from the culture broth of a streptomycete designated as strain MCRL 0387 and identified as a new variety of Streptomyces humidus NAKAZAWA and SHIBATA in IMAMURA et al., 1956. Ultra-violet irradiation of strain MCRL 0387 gave a high-yielding mutant which formed blue aerial mycelium instead of the grayish aerial mycelium of the original strain. Fermentative production of the antibiotics YA-56 complex is described.