[Effect of preservation conditions on the viability and activity of Streptomyces griseus--producer of the antibiotic grizin].

Strain AURIGenetics- 1552 of Str. griseus producing grisin used as a feed additive was obtained in the course of stepped selection. It is deposited at the Central Collection of Industrial Microorganisms of the USSR and designated as strain S-248. The strain was stored under varying conditions and their effect on its viability, morphological variation and antibiotic potency was studied. Investigation of the strain variation with respect to the cultural and morphological properties and the antibiotic production revealed definite correlation between the morphological properties of the culture and its capacity for the synthesis of the antibiotic. The medium G-1 containing KNO3 as the only source of nitrogen was found to be advantageous for maintaining the strain potency on storage with the method of subcultures or under a layer of mineral oil. It was shown that the strain can be successfully stored by lyophilization. This method in combination with selection of active variants from populations of lyophilized cells provided not only maintenance of the culture potency at the required level but also its increase.