Novel Long-Term Phytase from Serratia odorifera: Cloning, Expression, and Characterization.

Abstract

The appA-So gene, encoding a phytase from Serratia odorifera, was cloned and heterologously expressed in Komagataella phaffii. The open reading frame of appA-So comprised 1281 bp that encoded a 426-amino acid protein, including a 27-amino acid signal peptide. The encoded phytase, AppA-So, showed 52% homology with other histidine acid phosphatases. The purified recombinant phytase showed optimal activity at 55 °C and pH 4.5, exhibiting enzymatic activity between pH 3.7 and 5.8, with a specific activity of 1123 U/mg at pH 4.5 and 37 °C. The AppA-So protein retained more than 85% of its initial activity after incubation in different pH conditions (pH 2.5-6.5) at 37 °C for 3 h. AppA-So activity was maintained over time and displayed a low Michaelis-Menten constant (Km) of 0.093 g/L. To the best of our knowledge, this is the first report of the cloning and characterization of the phytase from S. odorifera. Comparison of AppA-So with other well-known phytases suggests that the S. odorifera phytase has the lowest Km and highest stable activity over time, making it very suitable for use in the animal feed industry.