Microbial phytases in skirmishing and management of environmental phosphorus pollution

Abstract

Phytases are acid phosphatases which catalyze the hydrolysis of phytic acid (myo-inositol hexakis(dihydrogen phosphate)) to inorganic phosphate and myo-inositol through a series of myo-inositol phosphate intermediates and making insoluble and unavailable phytic acid available for animal assimilation. Phytic acid is a major stored form of organic phosphorus in plants such as cereal grains, legumes and oilseeds. The accumulation of phosphorus at intensive livestock production area has raised serious con- cerns of environmental pollution. Phytases are of significant value in effectively combating environmental phosphorus pollution. The microbial sources of phytases include bacteria, moulds and yeasts. The supplementation of animal feeds with microbial phytases increases the bioavailability of phosphorus and minerals, besides reducing the aquatic phosphorus pollution in the areas of intensive livestock production. Microbial phytases are produced by solid state and submerged fermentations. The molecular masses of microbial phytases are in the range of 35-500 kDa depending upon the source, and they are active within a pH and temperature ranges of 4.5-7.5 and 45-70°C. Phytases not only degrade phytic acid but also ameliorate the nutritional status of the foods by making minerals such as iron, magnesium, zinc, phosphorus and proteins available for monogastric animals. This chapter describes the sources, production, characterization and applications of microbial phytases in phosphorus pollution management.