Phytase is a natural enzyme used to improve the nutritional quality of phytic acid rich feed components (mainly wheat bran for pigs). The supplementation with phytase decreases the need for calcium phosphate addition and has a positive effect on environment (less manure to be spread in fields).

Phytase is used as an animal feed supplement to enhance the nutritive value of plant material by liberation of inorganic phosphate from phytic acid (myo-inositol hexakisphosphate) and, thereby, to reduce environmental phosphorus pollution. For feed application a thermostable phytase is of general interest to circumvent problems that may occur during the formulation and feed pelleting process where temporarily high temperatures (80-100 °C) and shear stress may affect protein structure and lead to activity loss.

Phytase can be purified from transgenic microbes. Phytase has also been produced recently in transgenic canola, alfalfa and rice plants. Use of these plants as feeds provides the same benefits as adding the purified enzyme to conventional crop diets. Initial studies demonstrated no adverse effects of these phytase-enhanced feeds on animal health. This transgenic approach may be able to avoid yield penalties because phytic acid production throughout these plants is normal and phytase enzyme production can be targeted specifically to the grain. The ability to take up plant phosphorus reduces the need for supplemental phosphorus in livestock feed. The use of phytase thereby reduces the amount of phosphorus excreted. This has led to increased pressure to allow phytase to be used in commercial feeds. Producers should check with their certifying body to determine if the form of phytase they want to use is permitted.