Publisher Summary
The chapter discusses the various aspects of phytase enzyme. Importance of phytic acid and hydrolysis products in plant and nutrition are discussed in the chapter. The highest yields of phytase enzyme are produced by a wild-type strain A. niger NRRL 3135 in a mineral salt medium in which total phosphate is limiting for growth and cornstarch and glucose are the carbon sources. Synthesis of the enzyme is repressed by phosphate in the wild-type strain. Aspergillus niger NRRL 3135 produces two phytases one with pH optima at 2.5 and 5.5 (phyA) and one with an optimum at pH 2.0 (phyB). It also produces a pH 6.0 optimum phosphatase that has no phytase activity. The chapter discusses the biochemistry of phytase and acid phosphatases—that is, its purification and characterization, sequence studies, active site determinations, enzyme engineering studies, cloning of phytase and acid phosphatases and immobilization studies with phytase and acid phosphatase. Phytase is covalently immobilized on Fractogel TSK HW-75 F, glutaraldehyde-activated silicate, and agarose. The chapter also discusses Phytase (phyA) cloned into tobacco and canola. The efficacy of feeding phytase to monogastric animals (poultry and swine) is also established in the chapter. Economics and potential effect of phytase on pollution abatement are also discussed followed by the summarization of the aspect of its future studies.