GB821310A - Recovery of tetracycline from an acidified fermentation mash - Google Patents

Abstract

Tetracycline is recovered from an acidified fermentation mash, which may be clarified, by adjusting the calcium ion content to a level corresponding to that of calcium oxalate, e.g. by adding thereto oxalic acid or ammonium oxalate and removing the precipitated calcium oxalate, adding to the clarified solution one or more quaternary ammonium compounds selected from alkyltrimethyl-ammonium halides and dialkyldimethyl-ammonium halides, adjusting the pH to 8 to 12 and preferably 9-10, and extracting the tetracycline from the aqueous solution with a substantially water-immiscible organic solvent such as butanol, amyl alcohol, methyl isobutyl ketone or chloroform. The quaternary ammonium compounds have the formula <FORM:0821310/IV (a)/1> wherein R is a chain of at least 8 carbon atoms and R1 is a 2 to 20 carbon alkyl group. "Arquad 16" (Registered Trade Mark) which is a monoalkyltrimethylammonium chloride in which the alkyl group consists of 90% hexadecyl, 6% octadecyl and 4% octadecenyl is preferred. Half to 3 moles. of the quaternary compound per mol. tetracycline is preferred. The tetracycline is recovered from the solvent extract by (a) adding an alkanol or alkoxyalkanol such as butanol and 2-ethoxyethanol followed by acidification with hydrochloric acid to form the hydrochloride, (b) adding water and adjusting the pH to 3 to 7 to produce neutral tetracycline, (c) adding an aqueous solution of urea and adjusting to pH 2.5 to 6.0 by means of an acid in order to precipitate tetracycline urea which is dissociated in the manner disclosed in Specification 821,309. Specification 704,079 also is referred to.