Patent GB-779570-A (GB)
Title: A new antibiotic streptolydigin
Filed: 1955-09-19
Abstract: A new antibiotic striptolydigin is produced by cultivating a streptolydigin-producing strain of Streptomyces lydicus especially S. lydicus NRRL-2433 under aerobic conditions in a culture medium containing assimilable sources of carbon, nitrogen and inorganic salts.  The pH of the medium is initially adjusted to 6.0 to 7.5 preferably 7.0, buffers such as calcium carbonate being present to maintain the pH, the temperature of cultivation is 20 DEG  to 32 DEG C. and especially 24 DEG  to 28 DEG  C. and the duration 2 to 5 days for submerged culture and 4 to 12 days for surface culture. Specified sources of carbon are glucose, sucrose, glycerol, starch, lactose and dextrin.  Nitrogen sources are nitrates, ammonium salts, soybean meal, brewers' yeast, distillers' solubles, corn steep liquor, casein, amino acid mixtures and pep <FORM:0779570/IV(b)/1> <FORM:0779570/IV(b)/2> tones.  Inorganic salts are such as yield ions of sodium, potassium, calcium, phosphate, chloride and sulphate. Trace elements may also be present.  Streptolydigin is recovered from the fermentation broth by (a) solvent extraction with a water-immiscible polar organic solvent or (b) adsorption. Specified solvents are chlorinated hydrocarbons, e.g. methylene chloride, ethylene dichloride and chloroform; alcohols such as 1-butanol, 2-butanol and amyl alcohol; ketones such as methyl isobutyl ketone and methyl amyl ketone; and alkyl esters of fatty acids such as ethyl acetate, propyl acetate, butyl acetate and amyl acetate.  Extraction of the filtered broth at pH 2.0 to 5.0 results in the recovery of the free acid form of streptolydigin, and at pH 6.0 to 12.0 the salt form of the antibiotic is recovered.  Recovery is obtained by removing the solvent or adding a non-solvent such as hexane, heptane or a petroleum fraction.  Adsorption is on a cationic, anionic or amphoteric ion exchange resin such as "Amberlite 1RC-50" (Registered Trade Mark), Dowen 1 (anionic quaternary ammonium resin) and "Permutit DR."  (Registered Trade Mark), activated alumina, activated carbon, silica gel or magnesium aluminium silicate.  Elution is by a water-immisicible polar solvent for the antibiotic.  Elution from carbon is facilitated by first treating the carbon with acetic acid. Streptolydigin forms salts with bases.  Salts specified are those of sodium, potassium, calcium, aluminium, barium, magnesium, 1-ethyl piperidine and tetramethyl ammonium hydroxide.  The salts are prepared by adding the base to a solution of the antibiotic in an organic solvent.  Examples illustrate the preparation of the sodium, potassium and calcium salts.  Streptolydigin (acid) is soluble in ethyl acetate, amyl acetate, diethyl ether, acetone, ethanol, dimethyl formamide, methylene chloride, chloroform, butanol and ethylene dichloride; substantially insoluble in water and hydrochloric acid; its crystals melt at 147 DEG  to 148 DEG  C.; optical rotation [a ]25D= minus 64 to minus 67 degrees (C, 2 per cent in 0.005NKOH in ethanol) minus 93 degrees (C, 1.6 per cent in chloroform) and minus 76 degrees (C, 1.78 per cent in dioxan); contains carbon, hydrogen, nitrogen and oxygen in the proportions of C=64.29 per cent, H=7.68 per cent, N=4.70 per cent, C-CH3=9.5 per cent; ultra-violet absorption spectrum in 0.01N ethanolic potassium hydroxide solution is detailed in Fig. 2 and in 0.01 alcoholic sulphuric acid in Fig. 1 (not shown); characteristic absorption in infra-red, when suspended in mineral oil, at following frequencies expressed in reciprocal centimetres 3550, 3400, 3280, 3070, 2500, 1700, 1643, 1615, 1550, 1223, 1204, 1069, 1035 and 976. Streptolydigin has a broad antibacterial spectrum and is useful in the treatment of humans (especially streptococcal infections and pneumonia) and animals (especially those caused by Pasteurella multocida).