Production of antibiotic SU-2 complex by a 2-deoxystreptamine idiotroph of Micromonospora sagamiensis

A 2-deoxystreptamine idiotrophic mutant of Micromonospora sagamiensis, KY 11509, was found to produce unknown antibacterial substances, which were named SU-2 complex. Each component, SU-1, SU-2 and SU-3 were isolated from a culture broth of KY 11509. Chromatographic data suggested that these components were new antibiotics. The antibiotics exhibited potent and broad spectrum of antibacterial activity. The amount of SU-1, SU-2 and SU-3 production reached their maximum level (197, 82 and 58 micrograms/liter, respectively) in 3 to 4 days. Addition of cobalt chloride markedly stimulated SU-1 production but suppressed SU-2 and SU-3 production. Isolation of a mutant possessing a higher productivity of SU-2 complex is also described.