[Mathematical model of the effect of inorganic phosphorus on the tetracycline biosynthesis process]. / Matematicheskaia model' vliianiia neorganicheskogo fosfora na protsess biosinteza tetratsiklina

A special apparatus with continuous dosing of substrates to flasks was used for experiments on the effect of inorganic phosphorus concentrations on the growth process of Act. aureofaciens and tetracycline biosynthesis. The experimental data showed that the character of the orthophosphorus effect on the mycellium growth and antibiotic biosynthesis was different. The relations were described with macrokinetic equations of Mono and Andrus type.

[Regulation of tetracycline biosynthesis by controlling the growth of the producer]. / Reguliatsiia biosinteza tetratsiklina putem upravleniia rostom produtsenta

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.

[Study of the growth patterns of Act. antibioticus and the biosynthesis of oleandomycin]. / Izuchenie zakonomernostei rosta Act. antibioticus i biosintez oleandomitsina

The study of some regularities of the oleandomycin-producing organism growth during the first stage of cultivation showed that an increase in the ammount of starch in the medium from 2 to 10 per cent promoted the growth and its specific rate. When the organism was cultivated on media with 2--6 per cent of starch, addition of ammonium sulfate in a concentration of 0.25--0.5 per cent was favourable for its growth. When the amount of starch was 8--10 per cent, ammonium sulfate in a concentration of 0.25--1.5 per cent had almost no effect on the growth and its specific rate. It was found that an increase in the amount of starch in the medium without ammonium sulfate promoted the mycelium growth and oleandomycin biosynthesis by 20 per cent, the time of cultivation being prolongated. Ammonium sulfate significantly stimulated the mycelium growth and decreased biosynthesis of oleandomycin. Additional introduction of starch solution in a concentration of 1 or 2 per cent during the first hours of the culture growth (24 hours) on the medium with 2 per cent of starch stimulated the growth, its specific rate and biosynthesis of oleandomycin by 20--30 per cent and the cultivation time increased. Simulataneous addition of starch and ammonium sulfate to the culture during the first hours of the growth (24 hours) decreased the biosynthesis of oleandomycin. The maximum respiration rate of the culture in flasks was registered in 24 hours, then it was followed by a decrease. Addition of starch and ammonium sulfate during the cultivation process, i.e. in 24, 48 and 72 hours increased every time the rate of the organism respiration.