Expression of recombinantPichia pastoris X33 phytase for dephosphorylation of rice bran fermented liquid
- 79 Downloads
TheAspergillus ficuum phytase genephyA was overexpressed inPichia pastoris X33 after replacing Buffered glycerol-complex medium (BMGY medium) using 1% (v/v) glycerol with fresh Buffered methanol-complex medium (BMMY medium) using 1% (v/v) methanol (on daily basis) as carbon sources. The phytase activity increased evidently with the induction time, and reached 200 U mL−1 after 9 days of induction. We examined the possibility of employing thus obtained phytase to recover phosphorus from the fermented liquid of rice bran. When the 0.1 M sodium acetate buffer was replaced with de-ionised water (pH 5.5±0.1) as an enzyme reaction solution, there was an increase in the phosphorus recovery with respect to time and reached 1.31% after 24 h incubation contributing to 81% release of inorganic P from the rice bran phytate. Studies on hydrolysis of rice bran phytate by the addition of different concentrations of phytase ranging from 0–200 U mL−1 produced through the recombinant yeast shows no significant effect in the rate of phytate hydrolysis at enzyme activities of 200, 100, 50 U mL−1. However, rate of hydrolysis varied significantly at 20, 5, 0 U mL−1 enzyme concentrations.
Key wordsphytase Pichia pastoris X33 phosphorus rice bran SDS-PAGE
Unable to display preview. Download preview PDF.
- Mayer A.F., Hellmuth K., Schlieker H., Lopez-Ulibarri Oertel R.S., Dahlems U., Strasser A. W. M., van Loon A. P. G. M. (1999). An expression system matures: a highly efficient and cost-effective process for phytase production by recombinant strains ofHansenula polymorpha. Biotech. Bioeng., 63:373–381.CrossRefGoogle Scholar
- Rimbach G.H., Ingelmann J., Pallauf J. (1994). The role of phytase in the dietary bioavailability of minerals and trace elements. Ernahrungsforschung. 39:1–10.Google Scholar
- Van Hartingsveldt W., van Zeijl C.M.J.G.M., Harteveld M., Gouka R.J., Guykerbuyk Luiten M.E.G., van Paridon R.G.M.M., Selten G.C., Veenstra A.E., van Gorcom R.F.M., van den Hondel C.A.M.J.J. (1993). Cloning, characterization and expression of the phytase-encoding genephyA ofAspergillus niger. Gene. 127; 87–94.CrossRefPubMedGoogle Scholar