Production of an extracellular phytase from a thermophilic mould Humicola nigrescens in solid state fermentation and its application in dephytinization

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 of thermophilic moulds, Humicolu nigrescens was selected as a potent phytase producer on the basis of zone of hydrolysis. The mould produced phytase (4828 U/g DMB) optimally in SSF using wheat bran at 45 degrees 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 was optimally active at pH 5.0 and 50 degrees C. The partially purified enzyme resulted in dephytinization of wheat and gram flour at 50 degrees C with the concomitant liberation of inorganic phosphate. Based on its biochemical properties and ability to clephytinize flours, phytase off! nigrescens could be a potential candidate for food and feed industries. (C) 2014 Elsevier Ltd. All rights reserved.