BIOCHEMISTRY OF THE USTILAGINALES: V. FACTORS AFFECTING THE FORMATION OF USTILAGIC ACID BY USTILAGO ZEAE

Abstract

In a study of factors affecting the formation of ustilagic acid by Ustilago zeae (PRL 119) in submerged culture, yields of the acid ranging from 5 to 23 mgm. per ml. were obtained in three to five days, depending upon the concentration of medium constituents and the rate of aeration. The media employed contained cerelose, urea, corn steep liquor, and inorganic salts. Yields of ustilagic acid were usually between 8 and 15 mgm. per ml., corresponding to 12 to 23% conversion of the available glucose, on a carbon basis. Yields of the acid increased with increasing rates of aeration. Urea gave slightly higher yields than did the ammonium salts tested. Corn steep liquor concentration was optimal at 0.06%. Yields of ustilagic acid increased with increasing cerelose concentration, but the rate of conversion of carbohydrate into the acid decreased. About the same yields of ustilagic acid were obtained in shaken 500-ml. flasks, in nine-liter, and 30-liter fermentors.