fr901228 producing strain under an aerobic condition examples of the carbon source include glucose galactose starch fructose dextrin glycerin maltose arabinose mannose and the like examples of the nitrogen source include inorganic or organic nitrogen compounds such as bouillon yeast extract peptone gluten meal cottonseed flour soy flour corn steep liquor dried yeast ammonium salts e g ammonium nitrate ammonium sulfate and ammonium phosphate or urea and the like it is preferred to combine a single carbon source and a single nitrogen source both of high purity but those of low purity each containing a small amount of a growth factor and a considerable amount of an inorganic nutrient may be used these sources may properly be used depending on needs the above described medium may contain an inorganic salt such as an alkali metal carbonate e g sodium carbonate potassium carbonate and the like an alkali metal phosphate a magnesium salt e g magnesium sulfate and the like a copper salt e g cupric nitrate and a cobalt salt e g cobalt acetate and liquid paraffin fatty oil vegetable oil mineral oil as well as an antifoaming agent such as silicon and the like if required preferably the culture is conducted under deep.