Yeast Nitrogen Base (YNB) media have been prepared according the formulae of Wickerham (1943-51) and Burkholder (1943). YNB is a well defined composition of salts, vitamins, amino acids and a nitrogen source for a vigorous growth of Sacharomyces cerevisiae.
Yeast Nitrogen Base without amino acids (YNB w/o AA), Y2025, is used for selecting yeasts based on amino acid and carbohydrate requirements. In Y2025, Ammonium Sulfate is included as a readily available nitrogen source for nitrogen assimilation. The medium includes all other vitamins, mineral salts and trace elements required for a vigorous growth of yeast cells. Compared to full YNB medium, Y2025 lacks Histidine, Methionine and Trypthophan. In combination with