A process for obtaining high yields of oxytetracycline by means of which, oxytetracycline streptomycetes

摘要

Oxytetracycline is produced by cultivating an oxytetracycline-producing strain of Streptomyces capuensis n.sp., especially strain C.B.S. 113.63, under submerged aerobic conditions in an aqueous nutrient medium containing assimilable sources of carbohydrate, nitrogen and inorganic salts including ammonium sulphate. Preferably, the inoculant is an 8 to 10-hour subculture of the micro-organism. A typical nutrient medium contains starch, corn steep, ammoium sulphate, calcium carbonate, ammonium chloride, cobalt chloride, lard oil and water. Maximum yields are obtained by initially using two-thirds of the total quantity of ammonium sulphate to be used in the culture medium and adding the remaining one-third after 40 to 80 hours of fermentation. The fermented broth is acidified to pH 2.0 and filtered. An alkaline solution such as aqueous sodium hydroxide or ammonia is added to pH 6 to 9 and the precipitated oxytetracycline is separated and may be further purified.