GB712547A - Antibiotic and methods of obtaining same - Google Patents

Abstract

An antibiotic sistomycosin is produced by inoculating a nutrient medium with Streptomyces viridosporus NRRL 2414, which is described, incubating the inoculated medium under aerobic conditions at a temperature of 20-35 DEG C. for 1 to 8 days and isolating the antibiotic so produced from the culture mixture. The medium may be liquid or solid, the culture submerged or surface. It is preferred to use an aqueous nutrient containing a source of assimilable carbon, proteinaceous material and mineral salts, having initial pH 6-8.2, especially 7.3-7.7, and submerged culture with aeration by air, oxygen, or an oxygen-containing gas at 25-28 DEG C. for 1-4 days. Light should be excluded. The air may be injected into the medium, or the medium may be sprayed into the sterile air. Suitable carbon sources are arabinose, fructose, galactose, lactose, maltose, rhamnose, xylose, glycerol, mannitol and glucose, starch, dextrin, fermentation and distillers' slops, corn steep water solids, corn steep liquor and fermentation residues, e.g. of butanol-acetone. Suitable proteinaceous materials are beef extract, acid hydrolysed casein, beef peptone, soybean oil meal, dried fermentation residues; water-soluble, defatted and partially hydrolysed soybean meal, mixed amino acids, urea and purines. Minerals are sodium chloride, calcium carbonate, monopotassium hydrogen phosphate and di-potassium hydrogen phosphate. The antibiotic is obtained from (a) the liquid culture by first filtering off the mycelium, and from (b) the solid culture by first extracting with a solvent such as water or methanol. The liquids so obtained are extracted with a water-immiscible alcohol, e.g. n-butanol, the solvent removed and the solid extract treated with a fat solvent such as chloroform. The residue is extracted with chloroform containing 10 per cent methanol, and the solution so formed passed down a column of a silicate ion-exchanger. The column is washed with chloroform-methanol of increasing methanol content, and then eluted with methanol. The residue after the removal of the methanol is extracted with water, and the antibiotic recovered by freeze drying. Sistomycosin is a neutral substance, effective in inhibiting the growth of eumycetes and having no effect on the growth of most gram-negative and gram-positive bacteria, and containing only C, H, O and N. It is soluble in water and methanol, less soluble in wet acetone and aqueous alcohols containing more than one carbon atom per molecule; insoluble in chloroform, diethyl ether, ethyl acetate, benzene and petroleum ether. Decomposed by light, it reduces cold aqueous potassium permanganate solution and boiling Benedict's solution; gives a positive Molisch test, a negative ferric chloride test, imparts a deep cherry-red-to-chocolate colour to warm concentrated sulphuric acid, no colour with hydrochloric acid and thymol. In water, it exhibits characteristic maximum and minimum absorption bands in the ultra-violet region of the spectrum. In a hydrocarbon oil, it shows a characteristic infra-red absorption spectrum.