ISP Medium No. 4 (Inorganic Salt Starch Agar) is recommended for cultivation and characterization of Streptomyces species as per International Streptomyces Project.The medium is used for characterization of Streptomyces species. Starch provides the energy source. Dipotassium phosphate acts as buffering system while sodium chloride maintains the osmotic equilibrium of the medium. The salts provide essential electrolytes and minerals.