Covalent immobilization of peanut β-amylase for producing industrial nano-biocatalysts: A comparative study of kinetics, stability and reusability of the immobilized enzyme

Stability of enzymes is an important parameter for their industrial applicability. Here, we report successful immobilization of beta-amylase (bamyl) from peanut (Arachis hypogaea) onto Graphene oxide-carbon nanotube composite (GO-CNT), Graphene oxide nanosheets (GO) and Iron oxide nanoparticles (Fe3O4). The Box-Behnken Design of Response Surface Methodology (RSM) was used which optimized parameters affecting immobilization and gave 90%, 88% and 71% immobilization efficiency, respectively, for the above matrices. beta-Amylase immobilization onto GO-CNT (bamyl@GO-CNT) and Fe3O4 (bamyl@Fe3O4), resulted into approximately 70% retention of activity at 65 degrees C after 100 min of exposure. We used atomic force microscopy (AFM), scanning and transmission electron microscopy (SEM and TEM), Fourier transformed infrared (FT-IR) spectroscopy and fluorescence microscopy for characterization of free and enzyme bound nanostructures (NS). Due to the nontoxic nature of immobilization matrices and simple but elegant immobilization procedure, these may have potential utility as industrial biocatalysts for production of maltose.