YM (Yeast Malt) Agar is prepared according to the formulation by Wickerham and used for the cultivation of yeasts, molds and other aciduric microorganisms. Peptone provides amino acids, peptides, and other nitrogenous compounds. Yeast Extract is a source of B-complex vitamins and minerals. Dextrose is the fermentable carbohydrate. Malt Extract is a source of carbohydrates, proteins, and nutrients. Agar is the gelifying agent.