Purification and biochemical characterization of phytase from Bacillus cereus isolated from gastrointestinal tract of African giant snail (Achatina fulica).

Abstract

Phytases are specialized enzymes meant for phytic acid degradation. They possess ability to prevent phytic acid indigestion, including its attendant environmental pollution. This study was aimed at investigating biochemical properties of purified phytase of B. cereus isolated from Achatina fulica. Phytase produced from Bacillus cereus that exhibited optimal phytate degrading-ability of all the bacteria isolated was purified in a three-step purification. The biochemical properties of the purified enzyme were also determined. The phytase homogeny of approximately 45kDa exhibited 12.8-purification fold and 1.6% yield with optima phytate degrading efficiency and maximum stability at pH 7 and 50°C. Remaining activity of 52 and 47% obtained between 60 and 70°C after 2h further established thermostability of the purified phytase. Mg2+ and Zn2+ enhanced phytate hydrolysis by the enzyme, while Na+ showed mild inhibition but Hg2+ severely inhibited the enzymatic activity. Km and Vmax were estimated to be 0.11mM and 55.6μmol/min/mL, displaying enzyme-high substrate affinity and catalytic efficiency, respectively. Phytase purified from Bacillus cereus, isolated from African giant snails, has shown excellent characteristics suitable for phytic acid hydrolysis and could be employed in industrial and biotechnological applications.