GB684417A - A new antibiotic and a process for the production thereof - Google Patents

Abstract

An antibiotic terramycin is obtained by cultivating Streptomyces rimosus (the cultural characteristics of which are described) or a mutant thereof, in an aqueous nutrient-containing solution under aerobic conditions, preferably at a temperature of 24 DEG to 30 DEG C. for 2 to 7 days under submerged conditions. The nutrient medium consists of (a) a carbohydrate source such as a sugar, starch or glycerol, (b) a source of organic nitrogen, e.g. soybean meal, wheat gluten, cottonseed meal, lactalbumen, an enzymatic digest of casein and tryptone; (b) growth substances such as distillers solubles and yeast extract; (d) mineral salts such as sodium chloride, potassium phosphate, magnesium sulphate and sodium nitrate; (e) buffering agent, e.g. calcium carbonate and, if desired, an antifoaming agent such as an animal or vegetable oil. The fermentation broth is preferably acidified to a pH below 4, the mycelium filtered off and the antibiotic recovered from the filtrate by (a) absorption on activated carbon at a pH 7, elution therefrom with acidulated water of pH 1.5 saturated with butanol and subsequent evaporation in vacuo of the eluate previously adjusted to pH 6 to 9. Alternatively, the p eluate may be extracted with butanol, the butanol extracted with N/10 hydrochloric acid and the pH of the aqueous solution adjusted to 5 by means of a synthetic anion exchange resin; or (b) extraction by means of a water-immiscible or partially water-miscible organic solvent such as butanol, amyl alcohol and the mono-phenyl ether of ethylene glycol, either at a slightly basic pH, especially 9, or at a strongly acid pH, preferably below pH 3.5. The crystalline antibiotic may be obtained by (a) partially evaporating in vacuo an acidified aqueous solution of the antibiotic at a pH 2.8; (b) adding sodium chloride and butanol to an aqueous solution of the antibiotic at pH 2.5, redissolving in methanol the precipitate which forms and adding water; and (c) using water of pH 3 and butanol in the counter-current distribution process. The antibiotic may be purified from the fermentation broth by the formation of (a) picrate; (b) aryl azo sulphonate, e.g. Orange II at pH 2 and subsequent treatment with barium chloride and (c) b -naphthalene sulphonate. Salts of organic and inorganic acids may be prepared by adding the acid, e.g. hydrochloric, sulphuric, phosphoric, citric, tartaric, and gluconic, to an aqueous suspension of the antibiotic, generally at below pH 2.5. Salts of metals may be prepared, e.g. the alkali metal salts, by adding the alkali metal hydroxide to an aqueous suspension of the antibiotic to a pH 9.5. Examples are given at the preparation of the hydrochloride and sodium salts. Terramycin is effective against gram negative and gram positive bacteria; is amphoteric, forming acid and metal salts; sparingly soluble in methanol and substantially insoluble in water and ether; the dihydrate contains 53.05 per cent C, 5.91 per cent H. 5.64 per cent N and 35.4 per cent O (by difference), the refractive indices of six-sided plate crystals is a =1.634\sB0.004, b =1.646\sB0.004, g =greater than 1.700 and a suspension in mineral oil shows absorption in the infra-red of the spectrum at the following frequencies: 3580, 3470, 3350, 3060, 1652, 1625, 1592, 1318, 1280, 1242, 1122, 1090, 1076, 1054, 1033, 1007, 938, 863, 840, 775, 708 and 679.