Catalytic Properties of Immobilized Phytase of Silvania hatchlandensis FG 3.9.1

Abstract

A phytase preparation was obtained from the cells of haloalkalitolerant bacteria identified as Silvania hatchlandensis isolated from the soil of a soda sludge storage facility. When the enzyme was immobilized in barium alginate gel and cross-linked with activated chitosan, 97 and 95% of the native protein activity, respectively, was retained. It was shown that 70% of the phytase activity was retained when using the enzyme immobilized in alginate and bound to chitosan over six consecutive reaction cycles. Immobilization resulted in an insignificant decrease in the maximum reaction rate and a decrease in the Michaelis constant. Immobilized phytase was more thermally stable compared to the free form of the enzyme: the thermal inactivation constant of the immobilized enzyme at 70°C decreased by 1.1–1.2 times. The immobilized enzyme retained activity at pH 3–12; the pH optimum of the enzyme after immobilization did not change and was equal to 5.0. The specific activity of the enzyme covalently attached to activated chitosan is higher than that of the native enzyme in low and high pH media. Immobilized phytase of haloalkalitolerant Silvania hatchlandensis can be used in feed production and other areas of agriculture.