Effects of some heavy metals on growth, pigment and antibiotic production by Streptomyces galbus.

A chromogenic strain of Streptomyces galbus 5ME-13 producing an antifungal antibiotic was used to study the effects of some heavy metals on growth, melanoid pigment and antibiotic production in culture. Mercury and nickel were highly toxic followed by cadmium while cobalt and chromium appeared to be less toxic. All the metals inhibited growth, pigment and antibiotic production with widely variable IC50 values. Cadmium and chromium at lower concentrations unusually stimulated growth and enhanced pigment production in the strain.