<p>The subject of this invention is a method for isolating tetracyclines from the broth after the biosynthesis or from the mother liquor after isolating crude bases by means of ion-exchange and sorption resins. The broth or the acid mother liquor are passed through a bed of slightly alkaline anion-exchange resin with the functional groups blocked by a mineral acid anion. The antibiotic containing eluate is adsorbed on the bed of macroporous resin and then desorbed by washing with a 15-60% aqueous acidified solution af acetone or of methanol. The pure compound is isolated from the eluate by a well-known method. The beds of anion-exchange and sorption resins are regenerated with an aqueous solution of acetone or of methanol containing to 80% by volume of the organic solvent with addition of 0,4-6% by weight of sodium or potassium hydroxide or of ammonia.</p>
