title: Biophysical characterization and activity analysis of nano-magnesium supplemented cellulase obtained from a psychrobacterium following graphene oxide immobilization.
abstract: 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 Kmby 6.7 folds at 8°C and 34 folds at 90°C. GO-MgN-cel showed 5 fold and 4.7 fold increase in Vmaxat 8°C and 90°C respectively than the untreated enzyme.When compared to native enzyme, GO-MgN-cel had t1/2(half life) and Edincreased 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.
authors.affiliation: National Institute of Cholera and Enteric Diseases, West Bengal, India.
authors.forename: N
authors.initials: N
authors.lastname: Dutta
authors.affiliation: National Institute of Cholera and Enteric Diseases, West Bengal, India.
authors.forename: S
authors.initials: S
authors.lastname: Biswas
authors.affiliation: National Institute of Cholera and Enteric Diseases, West Bengal, India. Electronic address: sahamk@yahoo.com.
authors.forename: M K
authors.initials: MK
authors.lastname: Saha
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism*; D055592:Biophysical Phenomena; D001709:Biotechnology; D002480:Cellulase / Q000302:isolation & purification / Q000378:metabolism*; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000378:metabolism; D006108:Graphite; D055772:Green Chemistry Technology; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008277:Magnesium Oxide / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology; D000072757:Protein Conformation, beta-Strand; D013696:Temperature; D013816:Thermodynamics
chemical_list: D001426:Bacterial Proteins; D004800:Enzymes, Immobilized; D008277:Magnesium Oxide; D006108:Graphite; D002480:Cellulase
keywords: Biophysical studies; Cellulase; Glutaraldehyde; Graphene oxide; Kinetic parameters; Magnesium oxide nanoparticle; Psychrobacteria; Purification; Storage stability