Biophysical characterization and activity analysis of nano-magnesium supplemented cellulase obtained from a...

Cellulase enzyme was purified from a psychrophilic strain of Bacillus subtilis obtained from east Himalayan mountains. The native enzyme showed optimum activity at 15°C and pH 8.0.The Magnesium oxide nanoparticle (MgN) supplemented enzyme when immobilized on graphene oxide nanosupport (GO), via glutaraldehyde as cross linker, showed 2.98 folds increase in enzymatic activity at 8°C and more than 3.5 folds activity increment at 90°C. The MgN-cel on graphene (GO-MgN-cel) showed a decrease in K_m by 6.7 folds at 8°C and 34 folds at 90°C. GO-MgN-cel showed 5 fold and 4.7 fold increase in V_max at 8°C and 90°C respectively than the untreated enzyme.When compared to native enzyme, GO-MgN-cel had t_1/2 (half life) and E_d increased by 72.5 fold and 2.48 fold respectively at 90°C; and 41.6 fold and 2.19 fold respectively at 8°C. Enzymatic activity of GO-MgN-cel was retained even after 12 repeated uses and showed storage stability at 4°C for more than 120days. This nanoparticle assisted immobilization technique can be utilized in bioprocessing industries which require functioning at these extreme ranges of temperature.