[The effect of the acidity of the medium and of the temperature on the growth and polysaccharide excretion of Bacillus subtilis under submerged cultivation].

Growth of Bacillus subtilis strains and excretion of polysaccharides have been studied under different environmental condition. These strains were studied as active antagonists of pathogenic microflora and were used for development of the biopreparation (probiotic), being efficient in treatment and prophylaxis of a number of bacterial infections of farm animals; the drug soon will be put into series production. The indices of accumulation of biomass of viable cells and exopolysaccharides (EPS) were used to study productivity of the strains. A possibility to increase yield in the production process was shown using the temperature factor and optimal pH of the culture medium under batch cultivation. The processes of the biomass and EPS accumulation were noncompetitive, almost coincided in time and were independent of the initial level of the pH of medium.