(744g) Novel High Surface-Area -Magnetoresponsive-Nano-Biocarriers for Efficient Saccharification of Biomass

Immobilization of enzymes on supports helps to improve the overall operational stability of enzymes by increasing their resilience towards changes in external factors like temperature and pH. Immobilization also facilitates easy separation, providing a facile route to recycle and reuse the enzyme, thus reducing the overall cost. The technique of alternate deposition of anionic and cationic polyelectrolytes has been used in the past, especially in the field of biosensors, to entrap metal nanoparticles and enzymes within the multilayer assembly. In our present work, we extend the application of the above technique to immobilization of cellulase on novel high surface area magnetic nanoparticle-modified-exfoliated graphite nanoplatelets. This work comprises of two phases. In the first phase, maghemite-magnetite decorated exfoliated graphite nanoplatelets (xGnP-MNP) were developed using polyelectrolyte based layer-by-layer assembly. In the next phase, we attach Accellerase-1000, a mixture of endoglucanase and β-glucosidase, on xGnP-MNP using a combination of weak polyacid brushes and spacer molecules. Weak polyacid brushes tend to show swelling behavior when the pH is increased beyond the pKa value. The degree of polyacid swelling can be easily tweaked by controlling the pH, thus providing us an effective handle to control the activity of immobilized enzymes. The effect of temperature variation on the activity of immobilized enzymes will also be shown. Facile separation of cellulase immobilized on maghemite-magnetite doped xGnP is possible by using small bar magnets. The activity of immobilized enzymes after repeated use would be shown. Cellulase activity is evaluated by using both soluble as well as insoluble substrates like 2% w/v carboxymethylcellulose (CMC) and avicel respectively.