Production of oxytetracycline using Streptomyces alboflavus (ATCC 15388)
Oxytetracycline is produced by cultivating a mutant of Streptomyces alboflavus under aerobic conditions at 22-30.degree.. Thus, sterile medium contg. corn steep liquor 10, sugar 10, CaCO3 1, (NH4)2HPO4 2, KH2PO4 2, and MgSO4.7H2O 0.25 g with tap H2O 1 l. was inoculated with 1 ml of a spore suspension of S. alboflavus mutant M-108-OX (ATCC 15388) and incubated in a rotary shaker at 25.degree. for 36 hr. One l. of the above culture was used to inoculate medium contg. tap H2O 120 l.; starch 6, corn steep liquor (50%) 2.7, CaCO3 0.72, (NH4)2SO4 0.8, NH4Cl 0.2, and sunflower oil 0.2 kg; CoCl2 0.18, CuSO4.5H2O 0.6, ZnSO4.7H2O 6, and FeSO4 0.18 g. Submerged fermentation was carried on at 26.degree. with stirring and sterile aeration. The pH dropped from 7.2 to 6.35 and the concn. of oxytetracycline was 6.6 g/l. after 150 hr of fermentation. Repeating the above but adding 8.4 g of N,.nu.'-dibenzylethylenediamine diacetate (NBED) before inoculation, after 50 and 120 hr increased the yield of oxytetracycline to 8.1 g/l. after 140 hr of fermentation. The broth from the 150 hr of fermentation was acidified to pH 1.5 with 25% H2SO4, filtered, and the mycelium was washed with H2O. To the 240 l. of combined filtrate and washings was added 2 g/l. of EDTA Na. The pH was adjusted to 6 with 12% NH4OH; 150 g of NBED was added and the pH was increased to 9.5 with 12% NH4OH. After stirring 3 hr the formed ppt. was filtered off and washed until the pH of the washings reached 7. The ppt. was dried at 50.degree. under vacuum. The dry ppt. was ground and then suspended in twice its wt. of MeOH. After stirring 0.5 hr it was acidified to pH 2 with gaseous HCl and then to pH 1.5 with 36% HCl. The mass was filtered, washed with MeOH, and dried for 6 hr under vacuum. Yield of oxytetracycline.HCl was 81%.