[Regulation of tetracycline biosynthesis by controlling the growth of the producer].

Regulation of the rate growth of Act. aureofaciens in batch fermentation by maintaining the concentrations of phosphorus, ammonium nitrogen, glucose and pH values at the levels favourable for intensive growth at the beginning of the process and after accumulation of the biomass at the levels optimal for retarded growth of the organism resulted in significant prolongation of the period of intensive antibiotic production, i.e. intensification of the fermentation process. Microscopic investigation of the organism development under conditions of regulated fermentation revealed the presence of significant amounts of free peripheral highly basophilic hyphae for a prolonged period of time. The hyphae possessed a capacity for growth and intensive metabolism unlike the control culture which was liable to early autolysis.