Phytase (myoinositol hexakisphosphate phosphohydro- lase, EC 3.1.3.8) catalyzes the hydrolysis of phytate to myo- inositol pentakisphosphate and orthophosphate. Improving the digestibility of proteins and increasing the availability of phosphorus and other minerals, which are usually chelated by phytic acid [6], diminishes the antinutritive properties
of phytate, and prevents environmental pollution. Thus, the ideal enzyme for the catalysis of such processes should have high catalytic specificity, resistance to proteolysis [7], and sta- bility at elevated temperatures and under acidic conditions [8].