Yeast Nitrogen Base without Amino acids and without Ammonium sulphateYeast Nitrogen Base without Amino Acids and without Ammonium Sulfate has the same formulation as Yeast Nitrogen Base without Amino Acids except that Ammonium Sulfate as a source of Nitrogen has been omitted to test the ability of yeast cells to assimilate different nitrogen sources for example Potassium Nitrate. Suspend 1. 9 gram powdered medium in 1 litre distilled water Store dry at room temperature