Studies of a Yeast Exacting towards p-Aminobenzoic Acid

SUMMARY: Certain single-cell strains of brewer’s top fermentation yeasts require p-aminobenzoic acid as an essential nutrient. Relatively large quantities of adenine, together with certain amino-acids, of which methionine and histidine were of prime importance, could substitute for the p-aminobenzoic acid. In the presence of adenine, histidine, and suboptimal amounts of methionine, the addition of any one of seven other amino-acids caused a marked stimulation of growth. These amino-acids were leucine, isoleucine, norleucine, valine, norvaline, tyrosine and phenylalanine.