title: Nano-magnesium aided activity enhancement and biophysical characterization of a psychrophilic α-amylase immobilized on graphene oxide nanosupport.
abstract: In the current literature we have devised an immobilization technique for conferring psychrostability to a cold active α-amylase (amy) enzyme by the use of magnesium nanoparticle (MgNP) and graphene oxide (GO). The GO-MgNP-amy nanocomposite showed enhanced enzymatic activity and thermostability at both upper (90°C) and lower (8°C) temperature extremes. The GO-MgNP-amy showed increased affinity towards substrate, reflected in the decrease in its Kmby 2.35 and 14.9-fold at 8°C and 90°C, respectively, than the untreated enzyme. GO-MgNP-amy showed 2.34-fold and 4.29-fold increase in Vmaxat 8°C and 90°C, respectively, than the untreated enzyme. When compared to native enzyme at 90°C, GO-MgNP-amy had t1/2(half life) increased by 44-fold with simultaneous increase in Edby 1.9-fold. Again at 8°C, GO-MgNP-amy had t1/2increased by 6.48-fold with simultaneous increase in Edby 2.21-fold when compared to the native enzyme. The enzymatic activity of GO-MgNP-amy was retained even after 12 repeated uses and showed storage stability at 4°C for more than 120 days. The ability of GO-MgNP to sustain and aggravate enzyme activity and stability at temperatures beyond the optimal range can be utilized in bioprocessing industries which requires functioning at these extreme ranges of temperature.
authors.affiliation: National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme - XM, Beliaghata, Kolkata, 70001 West Bengal, India.
authors.forename: Nalok
authors.initials: N
authors.lastname: Dutta
authors.affiliation: National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme - XM, Beliaghata, Kolkata, 70001 West Bengal, India.
authors.forename: Subrata
authors.initials: S
authors.lastname: Biswas
authors.affiliation: National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme - XM, Beliaghata, Kolkata, 70001 West Bengal, India. Electronic address: sahamk@yahoo.com.
authors.forename: Malay Kumar
authors.initials: MK
authors.lastname: Saha
mesh_terms: D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D006108:Graphite / Q000737:chemistry*; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004800:Enzymes, Immobilized; D010087:Oxides; D006108:Graphite; D000516:alpha-Amylases; D008274:Magnesium
keywords: Biophysical studies; Glutaraldehyde; Graphene oxide; Kinetic parameters; Magnesium oxide nanoparticle; Psychrobacteria; Purification; Reusability; Storage stability; α-Amylase