A strategy for improving peroxidase stability via immobilization on surface modified multi-walled carbon nanotubes
authors Azevedo, RM; Costa, JB; Serp, P; Loureiro, JM; Faria, JL; Silva, CG; Tavares, APM
nationality International
author keywords peroxidase; carbon nanotubes; characterization; immobilization; stability
abstract BACKGROUNDDue to their exceptional mechanical, electrical and chemical properties, carbon nanotubes (CNT) have been used in the nanotechnology field to create new nanostructures. Consequently, there is an increasing interest in understanding and controlling the interactions of this nanomaterial with biological molecules, such as enzymes. In this context, peroxidases have been immobilized on CNT for various potential applications, such as sensing, drug delivery and biocatalysis. There are but a few studies about the influence of the nanoscale environment on the function of these enzymes. RESULTSOxygen functional groups are introduced by the oxidation of multi-walled carbon nanotubes (MWCNTs) in an initial step and then selectively removed by a thermal treatment at well defined temperatures. The immobilization efficiency and catalytic activity of peroxidase were analyzed as a function of the pH. Pristine MWCNTs show excellent immobilization capacity (100%) and high enzyme activity, but low thermal stability (at 40 degrees C) owing mostly to hydrophobic interaction between peroxidase and the support. MWCNTs oxidized with HNO3 and at posteriori heated at 400 degrees C, mostly presenting hydroxyl surface groups, provided the best compromise between peroxidase activity and thermal stability, which has been attributed to the formation of hydrogen bonds between the enzyme and the support. The storage stability of peroxidase immobilized on that support was 4.5 times higher than for the free peroxidase. CONCLUSIONMWCNTs present high affinity to adsorb peroxidase, which makes them excellent supports for the immobilization and stabilization of this enzyme, which constitutes a great advantage for industrial applications. (c) 2015 Society of Chemical Industry
issn 0268-2575
year published 2015
volume 90
issue 9
beginning page 1570
ending page 1578
digital object identifier (doi) 10.1002/jctb.4698
web of science category Biotechnology & Applied Microbiology; Chemistry, Multidisciplinary; Engineering, Environmental; Engineering, Chemical
subject category Biotechnology & Applied Microbiology; Chemistry; Engineering
unique article identifier WOS:000358611600005
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