A new streptothricin family antibiotic producing streptomyces spp. SNUS 8810-111; characterization of the producing organisms, fermentation, isolation, and structure elucidation of antibioitics

A new streptothricin family antibiotic producing Streptomyces spp. SNUS 8810-111 was isolated from a soil sample. Study of its morphological and physiological characters indicated that the antibiotic producing organism was a Streptomyces spp. Taxonomical studies suggested that the organism might belong to the genus Streptomyces gougeroti. The organism produced antibiotics most in calcium carbonate-tryptic soy broth. The active principles were recovered from the broth with a cation exchange resin and eluted from the resin with HCl. Cellulose column chromatography gave two active principles. ¹H-¹H Homo-COSY study on the first compound revealed four structural components. Total hydrolysis of the antibiotic with HCl allowed isolation of β-lysine. From these data the antibiotic was found to be streptothricin D. The other compound showed one additional signal in the ¹H NMR and the ¹³C NMR spectra. The signal was from a methyl group attached to a nitrogen atom. Comparison of the NMR signals with those of streptothricin D suggested that the compound was N-methylstreptothricin D which was a new compound in the family of streptothricin antibiotics.