Cloning and Overexpression of Phytase Gene appA form Escherichia coli / 微生物学通报

A strain Escherichia coli with high production of phytase was screened from pig excreta. Phytase gene appA, with 1,299 bp coding region in full length, was cloned from its genome by polymerase chain reaction (PCR) . The gene appA was then cloned into the prokaryotic expression vector pET-28a ( + ) . In the host BL21, the phytase appA was overexpressed by shaker-cultivation (up to 692 U/mL) . The enzymatic analysis of the prokaryotic derived appA phytase revealed that its optimal pH and temperature was 4.5 and 60℃, respectively.