SCREENING AND PRODUCTION OF PHYTASE FROM SOME BACTERIAL GENERA

The objectives of the present study were to screen for production of phytases by some bacterial genera. Phytases were produced by E. coli, Bacillus amyloliquefaciens strain DSM 7 and Klebsiella sp. Strain ASR1 which were compared to a commercial Aspergillus phytase. The E. coli phytase was recovered from the fermentation medium with total phytase activity of 2000 units per gram lyophilized supernatant. The Bacillus amyloliquefaciens phytase was had an average activity of 0.4 units per milliliter and 24 phytase units per gram after it was lyophilized. The Klebsiella sp. Strain ASR1 phytase average yield was 7.0 units per milliliter and 88.0 FTU/g after lyophilization, while Aspergillus phytase had 5000 units of activity per gram. pH profile, temperature optima, thermostability as well as enzyme kinetics and molecular weight were investigated in the different phytases in vitro. Aspergillus, E. coli and Klebsiella phytases displayed optimal activity in acidic pH range while Bacillus phytase in neutral pH. Bacillus phytase was more resistant to heat treatment. The Km and Vmax values for E. coli phytase were higher compared to other phytases.