GB742589A - Recovery of polymyxin - Google Patents

Abstract

Polymyxin is purified by contacting an aqueous solution of polymyxin with an ion-exchange material deriving its exchange capacity from carbonyl groups and eluting the polymyxin adsorbed on the material with an electrolyte solution. The ion-exchange material is either a synthetic resin or a non-resin such as cotton wool succinate. The resin may be (a) copolymer of acrylic or methacrylic acid with divinyl benzene, or (b) condensation product of aldehyde with a phenol, e.g. formaldehyde and resorcylic acid. The polymyxin solution may be a fermentation broth which has been subjected to preliminary purifications treatments such as hydrolysis, clarification by filtration, heating or chromatographic adsorption. Adsorption is at pH 3.5 to 9.0 and preferably pH 4.5 using an ion-exchange resin either as the free acid or partially converted to an easily replaceable salt form. Any solution of electrolyte may be used for elution; preferred are aqueous mineral acids such as hydrochloric and sulphuric and aqueous calcium chloride. Regeneration of the resin is by dilute mineral acid at pH 1 to 2 followed by water washing to pH 3.5 to 5 or treatment with a buffer solution. The purification process may be carried out by batch or column arrangements.