[Effect of cobalt on the growth of a Micromonospora purpurea var. violacea 1935 culture and on the biosynthesis of gentamincin].

The effect of cobalt on growth of Micromonospora purpurea var. violacea 1935 and biosynthess of gentamicin in complex soy-bean meal or "synthetic" gelatin medium was studied. In optimal concentrations cobalt increased the activity level of the culture fluid almost 6 times in both media having practically no effect on the amount of the mycelium formed. Addition of cobalt to the medium resulted in retardation of the organism growth and consumption of the nutrients. Stimulation of gentamicin biosynthesis by cobalt was inversely proportional to the time of the trace element addition. The cobalt effect depended on the aeration conditions, inorganic phosphorus level in the medium and physiological condition of the mycelium.