GB781843A - Pretreatment of aqueous nutrient-containing fermentation media to improve the yield of tetracycline therefrom - Google Patents

Abstract

An aqueous nutrient containing fermentation medium for the production of tetracycline using a tetracycline-producing-species of Streptomyces is contacted with an anion exchange resin to reduce the chloride ion content thereof and thereby improve the yield of tetracycline. The chloride ion content should be reduced to less than 50 parts per million and preferably less than 10 parts per million. Mixed beds of anionic resin and cationic exchange material are used where it is desired to remove cationic groups, e.g. metallic cations present in sufficient amounts to poison the nutrient medium. It is preferred to treat naturally-occurring materials such as corn steep liquor, animal stock liquor (crude mixture obtained from slaughter houses), starch and casein digests, and then to add the other ingredients of the fermentation medium, especially the mineral salts, to the de-chlorinated material. The fermentation medium contains a source of carbon, nitrogen and mineral salts. Viscous liquids are first diluted with water before passing through a bed of the ion exchanger. Insoluble materials may be washed with deionized water to remove chlorine ions. The anion exchange resins are any water-insoluble resins which will adsorb or otherwise remove chloride ions from aqueous solution, e.g. phenol-formaldehyde-polyamine condensates, melamine-guanidine-formaldehyde resins and polyalkylene polyamine resins. The resin may be operated in various forms such as the sulphate, nitrate, hydroxyl and phosphate cycles.