Abstract
The growth factor requirements of the experimental strain of E. ashbyi were found to be closely associated with variations in the pH of the medium. Only certain amino acids were required at certain pH levels and there was a pH range where no additional factors were required. Methionine, histidine, and tyrosine were the amino acids required at the different pH ranges. Histidine plays a very important role in the biosynthesis of riboflavin by this fungus.