Verfahren zur Herstellung von Oxytetracyclin

Oxytetracyline is produced by cultivating Streptomyces henetus (I.M.I. 109532; I.M. 3872) nor. spec. under aerobic conditions in a nutrient medium. A typical medium contains starch, corn steep liquor, calcium carbonate, casein, (NH4)2SO4, K2HPO4 and water. The pH of cultivation is 6.1 to 8.0 and temperature is 24 DEG to 37 DEG C. The broth is acidified to pH 2 to 2.5, clarified, treated with oxalic acid, clarified, adjusted to pH 8-8.5, extracted with a mixture of tricresol and CCl4, the organic phase separated, treated with aqueous HCl and acetone and oxytetracycline recovered from the aqueous phase at pH 7.0. The oxytetracycline may be converted into a salt with a mineral or organic acid, e.g. citric or tartaric acid. Other methods of isolation and purification are (a) solvent extraction with, e.g. butanol, (b) adsorption on, e.g. activated carbon, (c) precipitation with substances capable of forming insoluble derivatives, e.g. N,N1-malonylurea and sulphates.