STUDIES ON ACTINOMYCETALES PRODUCING ANTIBIOTICS ONLY ON AGAR CULTURE .1. SCREENING, TAXONOMY AND MORPHOLOGY-PRODUCTIVITY RELATIONSHIP OF STREPTOMYCES-HALSTEDII, STRAIN SF-1993

Soil Actinomycetales that produce antibiotics during growth on agar but not in submerged culture were searched for and about 25 strains were obtained. One of these, Streptomyces halstedii, strain SF-1993, which produces an antibiotic designated SF-1993 was studied taxonomically and morphologically. The antibiotic-productivity of strain SF-1993 was correlated with mycelial morphology. The vegetative mycelium was filamentous in antibiotic-producing agar cultures, but fragmented in non-producing submerged cultures. By maintain-ing submerged cells filamentous, production of antibiotic in the submerged fermentations was accomplished. Filamentation was maintained by the use of diluted media or non-frag-mented mutant substrains. © 1979, JAPAN ANTIBIOTICS RESEARCH ASSOCIATION. All rights reserved.