Author(s)

Edward Mullaney, Kandan Sethumadhavan, Stephanie Boone, Xin Gen Lei, Abul H. J. Ullah

Department of Animal Science, Cornell University, New York, USA.
Southern Regional Research Center, ARS, USDA, New Orleans, USA.

In this study, the optimum temperature was lowered while the residual phytase activity after heating to 70℃ was raised in a widely utilized phytase, Aspergillus niger NRRL 3135 PhyA. This was accomplished by site-directed mutagenesis of the cysteines that are involved in the formation of a single disulfide bridge (DB). When compared to wild type (WT), three of the four mutant phytases displayed a lower optimum temperature, 42℃, and up to a four-fold increase in activity after heating. These findings have a potentially broad application to be incorporated along with other desirable features to engineer a phytase with superior physical and chem-ical attributes for animal feed applications.

Phytase; Disulfide Bridge; Aspergillus niger; Site-Directed Mutagenesis

Mullaney, E. , Sethumadhavan, K. , Boone, S. , Lei, X. and Ullah, A. (2012) Elimination of a disulfide bridge in Aspergillus niger NRRL 3135 Phytase (PhyA) enhances heat tolerance and optimizes its temperature versus activity profile. Advances in Biological Chemistry, 2, 372-378. doi: 10.4236/abc.2012.24046.