Entrapment of commercially important invertase in silica particles at physiological pH and the effect of pH and temperature on enzyme activity

We report a simple and economic method to entrap invertase inside silica particles using a biosilicification process at physiological conditions. Larger silica particles (invertase-Si hybrid particles) were formed in the presence of invertase while smaller silica particles were observed in the absence of invertase. The invertase-Si hybrid particles were highly stable and active above the optimum conditions of pH (5) and temperature (50 °C) of the free invertase. The enhanced stability could be attributed to the protective nature and rigidity of silica particles that reduce the freedom of conformational changes of enzymes at higher pH and temperatures. The invertase-Si hybrid particles have an excellent reusability with a significant activity (76%) after 9 cycles of repeated use. This simple route to prepare invertase-Si hybrid particles with enhanced stability might have potential applications in food, beverage and confectionary industries.