GB691786A - Recovery of streptomycin from solutions thereof - Google Patents

Abstract

In the process of the parent Specification, the carboxylic type ion-exchange resin employed for adsorption of streptomycin is one formed by the copolymerization of a divinyl compound (e.g. divinyl benzene) and a polymerizable acid (e.g. acrylic or methacrylic acid). Advantageously a column of resin in the form of a salt (e.g. its sodium salt) is used, e.g. in a three-step cycle consisting of passing a clarified streptomycin-containing broth through the column, eluting the adsorbed streptomycin with a solution of acid, and regenerating the resin by passing a solution of a base (e.g. sodium hydroxide) through the column, followed by washing with water. It is also possible to use the resin otherwise than in a column, to use it in its hydrogen form, and to use calcium chloride solution as eluting material. The resin should preferably contain only 2.5-5.0 per cent of the divinylbenzene component in order that it may have a high porosity. The broth treated should desirably have a pH above 4.5 (preferably about neutral point) and be freed from calcium and other ions liable to interfere with the process. The streptomycin may be recovered from the eluate (which also contains metal salts) by evaporating (preferably under reduced pressure) to small volume or to dryness, taking up the residue in methanol or other solvent for streptomycin in which the salts are insoluble, filtering, precipitating streptomycin from the filtrate (e.g. with acetone), filtering and drying, and, if desired, converting the product to its crystalline calcium chloride complex salt by dissolving it in methanol and adding calcium chloride. In examples, a copolymer of 95 per cent of methacrylic acid and 5 per cent of divinylbenzene is used in the form of (1) its ammonium salt, and (2) its sodium salt, elution being effected with dilute hydrochloric acid. Example (3) gives comparative results with this resin, one containing 10 per cent of divinyl benzene and a carboxylic resin believed to be of the phenolformaldehyde type (all eluted with hydrochloric acid), a sulphonated phenol-formaldehyde resin and a sulphonated coal resin (both eluted with sodium chloride solution or aqueous sulphuric acid), a silicate exchange resin (eluted with sodium chloride solution), carbon (eluted with acidified aqueous methanol) and fuller's earth (eluted with an aqueous solution of pyridine hydrochloride). Specification 638,664 also is referred to.