In view of increasing demand of phytase, it is essential to produce and characterise cost-effective phytase from a new microbial source. Solid state fermentation (SSF) is the promising technology for commercial enzyme production with lower production cost. Among six isolates o f thermophilic moulds, Humicola nigrescens wa s selected as a potent phytase producer o n the basis of zone of hydrolysis. The mould produced phytase (4 8.28 U/g DMB) optimally in SSF using wheat bran at 451 C, pH 5.0 after 2 days with substrate to moisture ratio of 1:2.5. Supplementation of wheat bran with sucrose and ammonium sulphate further enhanced phytase production. Phytase of H. nigrescens was partially purified 3.3-fold using ammonium sulphate precipitation. The partially purified enzyme wasoptimally active a t p H 5.0 and 50 1 C. The partially purified enzyme resulted in dephytinization of wheat and gram fl our at 50 1 C with the concomitant liberation of inorganic phosphate. Based on its biochemical properties and ability to dephytinize flours, phytase of H. nigrescens could be a potential candidate for food and feed industries.
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