The natural variability of strain
Streptomyces galbus
(F) subsp. achromogenes 695 was examined. The changes of three characteristics: morphology of the colonies, formation of diffusible pigment and antibiotic activity, were studied on 21 agar media.
It was established that the polymorphism of the strain was the greatest on Gauze's No1 medium. Its population divided into four morphological types of colonies and one subtype of type I, which differed in the development stage of the aerial mycelium and in the colour intensity of the aerial and vegetative mycelium and of the soluble pigment.
A positive correlation between the antibiotic activity and the biosynthesis of diffusible pigment was observed.
The variants of the basic (I) morphological type had the highest antibiotic activity. Strain 695-3, which activity was with 20% higher than the one of the initial culture, was chosen for further selection.
