[Phosphate regulation of the processes of growth and biosynthesis of gentamicin in Micromonospora purpurea var. violaceae].

The influence of orthophosphate on isogenic strains of the gentamicin-producing organism with various levels of the antibiotic production was studied. An increase in the content of inorganic phosphate in the medium led to inhibition of the growth and gentamicin biosynthesis in all the strains: the low-active strains were more stable to the effect of the phosphate as compared to the highly active strains. Heterogeneity of the population of the strains was shown in respect of decreasing the growth rate and the level of the antibiotic biosynthesis inhibition in the presence of orthophosphate. Among the phosphate low-controllable forms there was a high number of low-active variants while among the clones with retarded growth and decreased production of the antibiotic there was a high number of productive variants. Inverse relationship between the antibiotic production level and the level of lability to the effect of inorganic phosphate was observed in the mutants of the gentamicin-producing organism.