[Obtaining mutants that yield tobramycin in a culture of the producer of a complex of aminoglycoside antibiotics, Streptomyces cremeus var. tobramycini var. nov. 2242].

The organism producing an aminoglycoside antibiotic complex was subjected to selection with a purpose of obtaining a strain producing tobramycin. Spontaneous and gamma-radiation-induced variation of the strains obtained as a result of a step-wise selection of the tobramycin-producing organism was studied. Correlation between the antibiotic activity levels and morphological features of these strains was shown. 8 physiological groups of mutants were differentiated and characterized as dependent on the ratio of the components in the aminoglycoside antibiotic complex produced by them. A highly productive strain 3406 was selected. The level of tobramycin synthesis by this strain is 10 times higher than that of the initial culture.