EXTRACELLULAR ORGANIC NITROGEN IN USTILAGO MAYDIS FERMENTATION BROTHS

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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.