Abstract
A chemically defined medium was devised in order to study the requirements for fortimicin A production by Micromonospora olivoasterospora KY 11515. Soluble starch was the best carbon source; NH4Cl and NH4NO3 were suitable nitrogen sources both for the growth and fortimicin production. Amino acids such as L-arginine, L-asparagine, L-aspartic acid and L-glutamic acid showed some stimulatory effects on both growth and antibiotic production of M. olivoasterospora while L-serine stimulated only antibiotic production and L-citrulline only the growth. K2HPO4, MgSO4•7H2O and CaCO3 were essential especially for the antibiotic production. The most important finding was that vitamin B12, cobalt and nickel showed marked stimulatory effects on fortimicin A production.