Enhancement and cultural characteristics of leucomycin production by Streptomyces kitasatoensis in the presence of magnesium phosphate.

Abstract

Stimulation of leucomycin production with Streptomyces kitasatoensis by magnesium phosphate (MgP), and a concomitant decrease of ammonium ion concentration in the culture supernatant have been reported from this laboratory. Cultural characteristics of the MgP-supplemented culture were further examined in relation to the stimulation of leucomycin production. When the leucomycin titer increased 4- to 5-fold in the presence of MgP, mycelial growth level and assimilation rate of a major carbon source (glycerol) increased about 2-fold. MgP-grown mycelia were not appreciably different in shape or in carbon and nitrogen contents from the control mycelia. Magnesium and phosphate ions were released from MgP into the medium, while the addition of magnesium or phosphate salts to the control medium was rather inhibitory for leucomycin production. The pH values of MgP-supplemented cultures were lower than those of the control culture. When modifications of the basal media and culture conditions were done so as to perm...