Tryptone Yeast Extract Broth (ISP Medium No. 1) is recommended as a general purpose enrichment medium for not particularly fastidious microorganisms. This medium is formulated as per International Streptomyces Project. Tryptone and yeast extract provide nitrogenous compounds, carbon, sulphur, vitamin B complex and trace elements, necessary for bacterial metabolism. With added carbohydrate and a pH indicator, it can also be used for fermentation studies.