IN VITRO COMPARISON OF PHYTASES FROM TWO MICROBIAL SOURCES

Abstract

The chemical properties of two different commercial microbial phytases (Natuphos and Ronoxyme P)        were compared. Natuphus production was based on the use of   a recombinant of Aspergillus niger        strain while the Ronoxyme P was from Peniophora lycii. The enzymes were studied for their optimum        pH, optimum temperature and enzyme stability, resistance to protease and stability in digesta super-        natants. The phytases were found to exhibit different properties depending on source of the phytase        gene and production organism. An optimum pH of 5.5 was recorded for the enzyme from Peniophora                                                                                                       0        lycii while pH of 5.0 was recorded for the enzyme from Aspergillus niger. Both phytases had 50 C as        their optimum temperature. The result of the enzyme - stability in aqueous solution indicated that the        Peniophora lycii phytase was more thermo-stable than the Aspergillus niger phytase. Incubation of the        phytases preparations with porcine proteases revealed that Aspergillus niger was more resistant to        pepsin and trypsin than Peniophora. Incubation of the phytases in digesta supernatants from various        segments of the digestive tract of hens revealed that digesta from the small intestine (SI) inactivated        the enzymes most efficiently. Nevertheless, the enzyme from Peniophora lycii retained more activity        than the enzyme from Aspergillus niger in all of the gastrointestinal tract (GIT). In conclusion, phyta-        ses of various microbial origins behave differently with respect to their in vitro properties, which could        be of importance for future developments of phytase preparation.