GB850325A - Production of a new antibiotic flavensomycin - Google Patents

Abstract

<PICT:0850325/IV(b)/1> An antibiotic flavensomycin having fungistatic, fungicidal and insecticidal properties is obtained by cultivating a flavensomycin producing stain of streptomyces cavourensis especially NCIB 8918 in an aqueous nutrient medium containing a source of carbon, nitrogen and mineral salts under surface or submerged, and preferably aerobic, conditions. The pH is preferably maintained at 7,8 8, the temperature is 24 DEG C. to 32C DEG . and preferably 27 DEG to 28 DEG C., the duration of fermentation is 3 to 7 days. The preferred medium contains meat peptone, corn steep liquor, maltose and water. For certain uses, e.g. insecticide, the broth may be used as such or after clarification. Flavensomycin may be isolated from the clarified broth by extraction with a water-immiscible solvent at pH 7,5 to 8,5 and especially 7,5 to 7,8. Specified solvents are benzene (preferred), ether, chloroform, butanol, ethyl acetate and gasoline. The extract is concentrated in vacuo and then purified by adsorption on alumina preferably after a preliminary purification by adding petroleum ether to precipitate the antibiotic which is then dissolved in acetone and re-precipitated by the addition of petroleum ether. The second precipitate is dissolved in benzene and treated with alumina preferably saturated with benzene (or other solvent X used in the preparation of the antibiotic solution), the alumina is washed first with benzene (or other solvent X) and then with ethyl acetate, the flavensomycin being eluted with methanol and recovered from the eluate by removing the solvent. Flavensomycin is an odourless lemon yellow crystalline powder, colour stable in acid and alkali; unstable in aqueous solution, stable as a dry powder; soluble in water, methanol, ethanol, propylene glycol, pyridine, n-propanol, n-butanol, amyl alcohol, glacial acetic acid, ethyl acetate, acetone, chloroform, dioxane and benzene; insoluble in glycerol, carbon tetrachloride, carbon disulphide, diethyl ether, hexane, gasoline and heavy hydrocarbons; having the elemental analysis C=63,73% H=8,04% N=2,27% and O= 25,96% having an ultra-violet adsorption spectrum showing a maximum at 251 Angstom units and infra-red absorption spectrum with absorption maxima as shown in the Figure.