Phytic acid (myo-inositol hexakis phosphate) is the principal form of phosphate store in cereals and oil seeds. Monogastric animals such as fish, pig and poultry are unable to utilize this phosphate source as they lack the enzyme phytase in their guts. Hence, feed formulations for these animals require inorganic phosphate as a supplement. Apart from adding to the costs of feeds, inorganic phosphate is a fast depleting resource and there is a need to conserve it. Phytate present in feeds acts as an anti-nutritional factor because it complexes with proteins and metals, and hence reduces their bioavailability. Phytate excreted in faeces creates the problem of phosphate pollution in areas of intensive monogastric livestock production. Hence enzyme phytase solves the environmental pollution problems.