Laccase immobilization over multi-walled carbon nanotubes: Kinetic, thermodynamic and stability studies
authors Tavares, APM; Silva, CG; Drazic, G; Silva, AMT; Loureiro, JM; Faria, JL
nationality International
journal JOURNAL OF COLLOID AND INTERFACE SCIENCE
author keywords Multi-walled carbon nanotubes; Characterization; Laccase immobilization; Kinetics; Thermodynamics
keywords REACTIVE TEXTILE DYES; TRAMETES-VERSICOLOR LACCASE; GREEN COCONUT FIBER; PHENOLIC-COMPOUNDS; COVALENT IMMOBILIZATION; COMMERCIAL LACCASE; MEDIATOR SYSTEM; OXIDATION; ENZYME; STABILIZATION
abstract The biocatalytic performance of immobilized enzyme systems depends mostly on the intrinsic properties of both biomolecule and support, immobilization technique and immobilization conditions. Multi-walled carbon nanotubes (MWCNTs) possess unique features for enzyme immobilization by adsorption. Enhanced catalytic activity and stability can be achieved by optimization of the immobilization conditions and by investigating the effect of operational parameters. Laccase was immobilized over MWCNTs by adsorption. The hybrid material was characterized by Fourier transformed infrared (FTIR) spectroscopy, scanning and transmission electron microscopy (SEM and TEM, respectively). The effect of different operational conditions (contact time, enzyme concentration and pH) on laccase immobilization was investigated. Optimized conditions were used for thermal stability, kinetic, and storage and operational stability studies. The optimal immobilization conditions for a laccase concentration of 3.75 mu L/mL were a pH of 9.0 and a contact time of 30 min (522 U-lac/g(carrier)). A decrease in the thermal stability of laccase was observed after immobilization. Changes in Delta S and Delta H of deactivation were found for the immobilized enzyme. The Michaelis-Menten kinetic constant was higher for laccase/MWCNT system than for free laccase. Immobilized laccase maintained (or even increased) its catalytic performance up to nine cycles of utilization and revealed long-term storage stability. (C) 2015 Elsevier Inc. All rights reserved.
publisher ACADEMIC PRESS INC ELSEVIER SCIENCE
issn 0021-9797
year published 2015
volume 454
beginning page 52
ending page 60
digital object identifier (doi) 10.1016/j.jcis.2015.04.054
web of science category Chemistry, Physical
subject category Chemistry
unique article identifier WOS:000356996700008
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journal impact factor 5.091
5 year journal impact factor 4.281
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