[Development of the system for protoplast generation in Streptomyces aureofaciens strains--chlortetracycline producers].

Conditions for preparation and regeneration of protoplasts in a commercial strain of the culture producing chlortetracycline and its derivatives were determined. The protoplasting level depended on the conditions of the mycelium cultivation and composition of a regeneration medium. Under the optimal conditions it amounted up to 10(6) protoplasts/ml. A mutant able to form regenerating protoplasts at a rate of 10(9) protoplasts/ml was isolated. An autoinhibition effect in regenerating protoplasts was observed. As a result ofprotoplast generationing, the morphological variation increased and the protoplast antibiotic activity changed within wide ranges. Variants with higher productivity in comparison to that of the initial strain were isolated. Stability of the inherited property of antibiotic production in the variants is being studied.