Fermentatives Verfahren zur Herstellung von Antibiotika

摘要

Antifungal antibiotics N-329A and N-329B, having substantially the same physico-chemical properties as antibiotics nonactin and valinomycin respectively, are produced by cultivating streptomyces tsusimaensis n. sp. especially S. tsusimaensis ATCC 15141 or a mutant or variant thereof in an aqueous nutrient medium containing a carbon source, a nitrogen source and trace inorganic elements at 25 DEG to 32 DEG C. under aerobic, preferably submerged, conditions. A typical medium contains corn starch, soybean meal, glycerol, corn steep liquor, calcium carbonate and sodium chloride in aqueous solution of pH 7.0. Yields of antibiotic N-329A or N-329B vary with temperature, degree of aeration and duration of cultivation. The broth is clarified using a filter aid and the separated cake extracted with a solvent such as acetone. The acetone is removed, the residual crude re-extracted with petroleum ether and the extract concentrated to form crystals, which on recrystallization from acetone, give pure antibiotic N-329A. The mother liquid is further concentrated, chromatographed on alumina and eluted with petroleum ether. After evaporation of the solvent from the eluate, the residue is crystallized from acetone or methanol to give pure antibiotic N-329B. The antibiotics are active against bacteria, fungi and yeast and are particularly useful for controlling pathogenic fungus growth on plants (see Division A5). ALSO:Germicidal agricultural compositions particularly effective against phytopathogenic fungi comprise antibiotic N-329A (or the closely related antibiotic nonactin) and for antibiotic N-329 B (or the closely related antibiotic valinomycin) in admixture with a solid or liquid carrier. Optional ingredients are other germicides, fertilizers, soil conditioners or plant growth regulants. The compositions may take the form of dusts, aerosols, self-emulsifying concentrates, emulsions or wettable powders.