[Role of cobalt in the biosynthesis of the components of the gentamicin complex].

It was shown that addition of cobalt ions or vitamin B12 to the fermentation medium resulted in an increase in the level of gentamicin accumulation, the relative content of the most methylated components C1 and C2 in the gentamicin complex being increased, while the content of the least methylated components CIa and "minors" decreased. Addition of sulphodimezine lowered the gentamicin biosynthesis rate and the relative content of gentamicins C1 and C2. It was supposed that cobalt stimulated the B12-dependent synthesis of methionine, being the source of the methyl groups for biosynthesis of the methylated components of gentamicin complex.