[Dependence of erythromycin biosynthesis on the active acidity of the medium]

Dependence of erythromycin biosynthesis on the medium active acidity was studied by the following methods: by changing pH of the initial medium, by changing the concentration of the medium components determining the active acidity of the culture, by using buffer mixtures by automatic control of pH. It was found that pH of the initial medium within 5.7-8.1 had no effect on the culture growth. Biosynthesis of erythromycin markedly decreased at pH 6.3 or lower. The values of pH within 6.6-7.5 (optimal values 6.7-6.9) were favourable for the antibiotic biosynthesis. At pH 6.2-6.3 the antibiotic accumulation was equal to 5-10 per cent of the control.