Effects of several metals on spore, biomass, and geosmin production by Streptomyces tendae and Penicillium expansum

Cultures of Streptomyces tendae and Penicillium expansum grown on Actinomyces and Czapek's media, respectively, were exposed to 5 mg L(-1) of manganese, magnesium, iron, cobalt, nickel, copper and zinc, supplied as sulfate salts. Only copper markedly increased geosmin (1 alpha, 10 beta-dimethyl-9 alpha-decalol), biomass, and spore production. Inductively coupled plasma-atomic emission spectrometric analysis of S. tendae and P. expansum cells did not indicate an accumulation of copper. Both 1 and 5 mg L(-1) copper, as copper sulfate, increased total geosmin production in cultures of S. tendae on several media, but decreased production on others, suggesting that substrate composition affects responses to copper.