EXTRACELLULAR ORGANIC NITROGEN IN USTILAGO MAYDIS FERMENTATION BROTHS

Abstract

Free amino acids and small peptides make up most of the extracellular organic nitrogen in media from shaken and aerated Ustilago maydis fermentations. Of the 3.5 mgm./ml. ammonia nitrogen added, 2.9 mgm./ml. remained in the extracellular broth. This extracellular nitrogen contained 1.17 mgm./ml. of organic nitrogen and 1.74 mgm./ml. of residual ammonia nitrogen. At least 53% of extracellular organic nitrogen is in the form of free amino acids. Fifteen amino acids were estimated quantitatively in acid-hydrolyzed broth and a particularly high level of arginine (1.14 mgm./ml.) was found. The amounts of methionine and tryptophan in the broth were quite low but the lysine concentration 0.400 mgm./ml. was relatively high.