One pot synthesis of α-amylase metal organic framework (MOF)-sponge via dip-coating technique.

Enzyme embedded metal-organic frameworks (MOFs) are blooming in the field of enzyme immobilization on account of their superior catalytic efficiency, thermal and chemical stability as compared to native enzyme. However, the separation and recovery of enzyme embedded MOF composite is quite challenging due to its nanometer size, high dispersity and low density which limits the reusability. In this work, α-amylase embedded zeolite imidazole framework (ZIF)-67 was fabricated onto melamine sponge using surfactant assisted dip coating technique. This was achieved in single pot making the method facile and rapid. α-Amylase MOF-sponge was analysed and characterized by FT-IR, XRD, SEM and TGA. We demonstrated that the encapsulation could maintain the active conformational structure of α-amylase after immobilization procedure with excellent bioactivity. Further, apart from merits of framework shielding, it offers mass transfer limitation for macromolecular substrate (like starch) which was determined and expressed as effectiveness factor (η) by using Michaelis-Menten enzyme kinetics. At the end, recycling studies were carried out for α-amylase MOF-sponge which showed 32% residual activity after six consecutive cycles. It is believed that this strategy has great potential in the field of continuous biotransformation (catalysis), biosensing and biomedicine application.