GB871221A - Recovery of antibiotics by means of ion-exchange resins - Google Patents

Abstract

Increased yields and facilitated recovery are obtained by adding to the fermentation broth during the fermentation a particulate ion exchange resin capable of adsorbing the antibiotic, allowing the fermentation to proceed in the presence of the resin, separating the spent fermentation broth and mycelium from the ion exchange resin and eluting from the ion exchange resin the antibiotic adsorbed on it. The resin is added to the broth at a period of time from the beginning of the fermentation or preferably after 48 hours to 1 hour but preferably 24 hours before the harvest of the broth. 1 to 5% by volume of resin is used. The resin is preferably sterilised prior to addition to the broth. If heat cannot be used, the resin may be sterilised by treatment with an antiseptic such as aqueous alcohol. In general, 10-200 mesh and preferably 35 to 100 mesh size resin is used. In recovering the antibiotic, it is preferred to dilute the broth with water and to separate the resin particles from the mycelium and spent broth by means of a suitable screen especially a vibrating screen. The antibiotic is eluted from the resin by means of an aqueous eluting agent containing an electrolyte. For acidic antibiotics such as novobiocin and penicillin, there is used a basic, highly porous, anion exchange resin. For basic antibiotics such as streptomycin, neomycin and eulicin, there is used an acidic, highly porous, cation exchange resin. In one example, Dowex 1-X2 resin (quaternary ammonium groups attached to a styrene divinylbenzene matrix) on the chloride cycle, previously sterilised by treatment with anhydrous ethanol, is added to a novobiocin fermentation broth at various stages in the fermentation, the resin is removed by a 70 mesh screen and the novobiocin eluted therefrom by means of 16% aqueous hydrochloric acid in methanol. In another example, Duolite C25 resin (sulphonated polystyrene divinylbenzene cation exchange resin) on sodium cycle, previously sterilised with 70% aqueous ethanol, is added to a neomycin fermentation broth 48 hours after the inoculation, the resin separated on a 28 mesh screen and the neomycin eluted with aqueous ammonia.