Microbial Phytases and Phytate: Exploring Opportunities for Sustainable Phosphorus Management in Agriculture

Myo-inositol phosphates (phytates) are important biological molecules produced largely by plants to store phosphorus. Phytate is very abundant in many different soils making up a large portion of all soil phosphorus. This review assesses current phytase science from the perspective of its substrate, phytate, by examining the intricate relationship between the phytate-hydrolyzing enzymes and phytate as their substrate. Specifically, we examine available data on phytate’s structural features, distribution in nature and functional roles. The role of phytases and their localization in soil and plant tissues are evaluated. We provide a summary of the current biotechnological advances in using industrial or recombinant phytases to improve plant growth and animal nutrition. The prospects of future discovery of novel phytases with improved biochemical properties and bioengineering of existing enzymes are also discussed. Two alternative but complementary directions to increase phosphorus bioavailability through the more efficient utilization of soil phytate are currently being developed. These approaches take advantage of microbial phytases secreted into rhizosphere either by phytase-producing microbes (biofertilizers) or by genetically engineered plants. More research on phytate metabolism in soils and plants is needed to promote environmentally friendly, more productive and sustainable agriculture.