Phytase of the unconventional yeast pichia anomala: Production and applications

Abstract

Most of cereal and legume seeds and their by-products contain 1-2% phytic acid (myo-inositol-1,2,3,4,5,6-hexakis dihydrogen phosphate) that represents >60% of total phosphorus content in plant products. A large portion of phytic acid in various plant seeds is in the form of salts called phytates. The phytate phosphorus is scarcely available to monogastrics (non-ruminants) because of insufficient levels of phytic acid hydrolysing gastric enzymes in them. Inorganic phosphorus (Pi) is supplemented in diets designed for such animals, which include swine, poultry, and fish to meet their Pi requirement. The unutilized phytate P is excreted that becomes an environmental pollutant in areas of intensive animal rearing. Excessive phytate P from soils flows to lakes and the sea that causes eutrophication, algal blooms and death of aquatic organisms. Furthermore, the negatively charged phosphate groups on phytic acid chelates positively charged metal ions of nutritional importance including Fe2+,Ca2+,Zn2+,Cu2+,Mg2+,Mn2+, causing poor absorption of the bound metals in gastrointestinal (GI) tract. This is one of the significant factors for causing wide-spread nutritional deficiencies of calcium, iron, and zinc in countries where plant based diets are predominantly consumed. Challenges in the areas of environmental sustainability, animal and human nutrition and health have prompted research on phytases. This review focuses on the production, properties and applications of native and recombinant phytases of Pichia anomala and scope of improving its potential through protein engineering.