Prevention of loss of Streptomycin production on repeated transfer of Streptomyces griseus.

The streptomycin-producing capacity of submerged cultures of Streptomyces griseus 107 was nearly lost during repeated transfers on synthetic nutrient medium. This effect did not occur on the same nutrient medium from which Fe(++) was omitted. The physiological reason for this effect was discussed from the point of the relationship of iron-containing porphyrin enzymes to the process of streptomycin biosynthesis.