Factors affecting the production of amphotericin A.
Factors affecting amphotericin A synthesis of Streptomyces nodosus, NDMC-034 were studied. Iron, magnesium and manganese were found to stimulate amphotericin A synthesis at concentrations ranging from 10-100 microM. The optimum inoculum size, and the pH of production medium before sterilization for producing amphotericin A, were found to be near 10% (v/v) and pH 7.8, respectively. Carrying out fermentation in a complex medium using pharmamedia as nitrogen source resulted in an amphotericin A yield of up to 3.4 g/liter. A novel isolation and purification process for amphotericin A from the fermentation broth was developed, using an extracting isopropyl alcohol and methanolic solution containing 2% CaCl2. Amphotericin A exhibits a much lower acute toxicity in mice than amphotericin B.