Biological metal organic framework (bio-MOF) of glucoamylase with enhanced stability.

The handling of conventional enzyme- metal organic framework (MOF) composites is big challenge due to their nano-sized and lightweight structure with low density. Also, conventional MOFs are derived from non-renewable petroleum feedstock which makes them inherent toxic and non-biodegradable. To overcome these difficulties, recently, green, renewable framework material composite, biological metal-organic frameworks (bio-MOFs) have intrigued as a novel class of porous materials. Here, glucoamylase was encapsulated within ZIF-8 in presence of functionalized carboxymethylcellulose (CMC) at mild aqueous conditions. The successful formation of glucoamylase bio-MOF was confirmed by Fourier transform infrared (FT-IR), X-Ray Diffraction (XRD) and scanning electron microscopy (SEM). In thermal stability, glucoamylase bio-MOF exhibited 187 % enhanced thermal stability in the temperature range of 55-75 °C as compared to native form. Further, glucoamylase bio-MOF was recycled for 5 cycles and compared their activity with traditional glucoamylase MOF. Glucoamylase bio-MOF showed significantly improved recyclability which was attributed by adhesive nature of CMC. Finally, the conformational change occurred in enzyme after immobilization was determined by FT-IR data tools.