title: Nickel-impregnated silica nanoparticle synthesis and their evaluation for biocatalyst immobilization.
abstract: In the present investigation, impact of nickel-impregnated silica paramagnetic particles (NSP) as biocatalyst immobilization matrices was investigated. These nanoparticles were synthesized by sol-gel route using a nonionic surfactant block co polymer [poly (ethylene glycol)-block-poly-(propylene glycol)-block-poly (ethylene glycol)]. Diastase enzyme was immobilized on these particles (enzyme-impregnated NSP) as model enzyme and characterized using Fourier-transform infrared spectroscopy and X-ray crystallography. Analysis of enzyme-binding nature with these nanoparticles at different physiological conditions revealed that binding pattern and activity profile varied with the pH of the reaction mixture. The immobilized enzyme was further characterized for its biocatalytic activity with respect to kinetic properties such as Km and Vmax and compared with free enzyme. Paramagnetic nanoparticle-immobilized enzyme showed more affinity for substrate compared to free one. The nature of silica and nickel varied from amorphous to crystalline nature and vice versa upon immobilization of enzyme. To the best of our knowledge, this is the first report of its kind for change of nature from one form to other under normal temperatures upon diastase interaction with NSP.
authors.affiliation: Bioengineering and Environmental Centre, Indian Institute of Chemical Technology, Hyderabad 500007, India. prakasam@iict.res.in
authors.forename: Reddy Shetty
authors.initials: RS
authors.lastname: Prakasham
authors.forename: G Sarala
authors.initials: GS
authors.lastname: Devi
authors.forename: Chaganti Subba
authors.initials: CS
authors.lastname: Rao
authors.forename: V S S
authors.initials: VS
authors.lastname: Sivakumar
authors.forename: T
authors.initials: T
authors.lastname: Sathish
authors.forename: P N
authors.initials: PN
authors.lastname: Sarma
mesh_terms: D000681:Amylases / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D055162:Biocatalysis; D018360:Crystallography, X-Ray; D004789:Enzyme Activation; D004800:Enzymes, Immobilized / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008320:Maltose / Q000138:chemical synthesis / Q000737:chemistry; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011409:Propylene Glycols / Q000737:chemistry; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry*; D013213:Starch / Q000737:chemistry; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D011409:Propylene Glycols; D013501:Surface-Active Agents; C528875:poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) copolymer; D011092:Polyethylene Glycols; D008320:Maltose; D012822:Silicon Dioxide; D009532:Nickel; D013213:Starch; D000681:Amylases