Purification and kinetics of a protease-resistant, neutral, and thermostable phytase from Bacillus subtilis subsp. subtilis JJBS250 ameliorating food nutrition

摘要

A novel protease-resistant and thermostable phytase from Bacillus subtilis subsp. subtilis JJBS250 was purified 36-fold to homogeneity with a combination of ammonium sulfate precipitation followed by Q-Sepharose and Sephadex G-50 chromatographic techniques. The estimated molecular mass of the purified phytase was 46kDa by electrophoresis with optimal activity at pH 7.0 and 70 degrees C. About 19% of original activity was maintained at 80 degrees C for 10min. Phytase activity was stimulated in presence of surfactants like Tween-20, Tween-80, and Triton X-100 and metal ions like Ca+2, K+, and Co+2 and it was inhibited by SDS and Mg+2, Al+2, and Fe+2. Purified enzyme showed specificity to different salts of phytic acid and values of K-m and V-max were 0.293mM and 11.49 nmoless(-1), respectively for sodium phytate. The purified enzyme was resistant to proteases (trypsin and pepsin) that resulted in amelioration of food nutrition with simultaneous release of inorganic phosphate, reducing sugars, and soluble protein.