Expression and characteristics of phytase from Bacillus licheniformis

The gene phy,from a thermophilic bacteria strain Bacillus licheniformis SR01,was cloned into prokaryotic expression vector p GEX-4T-3 to construct the recombinant strain p GX1143,and it was successfully efficiently expressed. The optimal p H and temperature for this phytase activity were 5.0 and 55 ℃,respectively. The enzyme had a wide range of p H stability and good thermal stability. And it was activated by Co²⁺,Li⁺,Mg²⁺,Ba²⁺,and inhibited by Cu²⁺,Pb²⁺,Fe²⁺,Ag⁺,SDS. However,it almost lost activity when influenced by Pb²⁺,Fe²⁺ and SDS. In addition,it had strong ability to resist hydrolyzation by trypsin and partial ability to resist hydrolyzation by pepsin.