Factors affecting fermentative production of magnamycin by Streptomyces halsted II

Potassium nitrate, NH4Cl and NH4NO3 were the best inorganic nitrogen sources suitable for biosynthesis of magnamycin by Streptomyces halstedii in a medium with glucose as carbon source. The best concentrations of KNO3, NH4Cl and NH4NO3 were 3·0g litre−1, 2·0g· litre−1 and 5·0g litre−1, respectively. Sodium acetate, sodium tartrate, sodium citrate, maleic acid and sodium propionate added to the KNO3 medium increased biosynthesis of magnamycin. Addition of l-cystine, β-alanine, l-leucine or l-glutamic acid also increased the antibiotic yield. l-Proline, glycine, dl-serine, l-aspartic acid, l-tyrosine, l-tryptophan, dl-isoleucine, l-lysine and dl-alanine had no effects on the biosynthesis of magnamycin. l-Valine retarded the antibiotic biosynthesis, while l-arginine inhibited completely the biosynthesis of magnamycin. The vitamins tested had no effect on the antibiotic production. FeSO4.7H2O and Co(NO3)2. 6H2O increased the biosynthesis while ZnCl2 and MnCl2.4H2O retarded the antibiotic biosynthesis. CuCl2.2H2O completely inhibited the biosynthesis of magnamycin.