A-21978 Antibiotics and process for their production

Abstract

Antibiotic A-21978 complexes, in particular the A-21978C complex, comprising microbiologically active, related factors C 0 , C 1 , C 2 , C 3 , C 4 , and C 5 . A-21978 complex and A-21978C complex are produced by submerged aerobic fermentation of Streptomyces roseosporus NRRL 11379. The individual A-29178C factors are separated and isolated by chromatography. The A-21978 and A-21978C complexes; the A-21978C factors; and pharmaceutically acceptable salts thereof are antibacterial agents and improve growth promotion in poultry.

We claim: 1. The A-21978 antibiotic complex which is produced by submerged aerobic cultivation of Streptomyces roseosporus NRRL 11379 or an A-12978-producing mutant thereof. 2. The method of producing A-21978 complex which comprises cultvating Streptomyces roseosporus NRRL 11379 or an A-21978-producing mutant thereof in a culture medium containing assimilable sources of carbohydrate, nitrogen, and inorganic salts under submerged aerobic fermentation conditions until a substantial amount of antibiotic activity is produced. 3. The method of claim 2 which includes the additional step of separating A-21978 complex from the culture medium. 4. The method of claim 3 which includes the additional step of isolating the A-21978C complex from the separated A-21978 complex. 5. The method of claim 4 which includes the additional step of isolating A-21978C factor C 0  from the separated A-21978C complex. 6. The method of claim 4 which includes the additional step of isolating A-21978C factor C 1   
     
        from the separated A-21978C complex. 7. The method of claim 4 which includes the additional step of isolating A-21978C factor C 2  from the separated A-21978C complex. 8. The method of claim 4 which includes the additional step of isolating A-21978C factor C 3  from the separated A-21978C complex. 9. The method of claim 4 which includes the additional step of isolating A-21978C factor C 4  from the separated A-21978C complex. 10. The method of claim 4 which includes the additional step of isolating A-21978C factor C 5  from the separated A-21978C complex. 11. The A-21978C antibiotic complex, which is produced by submerged aerobic cultivation of Streptomyces roseosporus NRRL 11379 or an A-21978C-producing mutant thereof; and which comprises factors C 0 , C 1 , C 2 , C 3 , C 4  and C 5 , which have the following structural formula: ##STR4## wherein 3MG represents L-threo-3-methylglutamic acid, and R represents a specific fatty acid moiety as follows: 8-methyldecanoyl (C 1 ), C 10  -methylundecanoyl (C 2 ), 10-methyldodecanoyl (C 3 ), C 10  -alkanoyl (C 0 ), C 12  -alkanoyl (C 4 ), and .[.C 13  -alkanoyl.]. .Iadd.C 12  -alkanoyl C 5 ).Iaddend..