Functionalized Multi‐Wall Carbon Nanotubes for Lipase Immobilization

Abstract

We examine the immobilization of lipase B from Candida antarctica on functionalized multi‐wall carbon nanotubes (MWCNTs) through physical adsorption. MWCNTs functionalized with carboxyl‐, amine‐ and ester‐ terminal groups on their surface are used as immobilization carriers. Dispersion of the nanotubes and the immobilization procedure take place in aqueous and low‐water media. High enzyme loadings are attained, up to 25% of the weight of the carbon nanotubes. These novel biomaterials are characterized though FT‐IR and Raman spectroscopy. The MWCNT–lipase bioconjugates exhibit high catalytic activity and increased storage and operational stability. The biomaterials retain more than 55% of their initial activity after 6 months at 4 °C, while they retain approximately 25% of their initial activity after 30 d of incubation in hexane at 60 °C. The catalytic behaviour of the immobilized enzyme depends on the terminal group of the carbon nanotubes, the concentration of the enzyme and the immobilization method employed.

Development of effective nanobiocatalytic systems through the immobilization of hydrolases on functionalized carbon-based nanomaterials

“…This enzyme loading value is particularly high compared to the published values for other types of carbon-based nanomaterials (Asuri et al, 2007;Cang-Rong and Pastorin, 2009;Karajanagi et al, 2004). In previous work, we have shown that the immobilization yield could be improved by using a lower enzyme to nanomaterial weight ratio, albeit at the expense of the enzyme loading (Pavlidis et al, 2010a). The high immobilization yield observed for both immobilization procedures may also result from the adsorption of enzyme molecules on top of those previously immobilized (covalently or non-covalently) on the support, in a similar manner as described for other type of nanomaterials (Tzialla et al, 2010).…”

“…The nanomaterials used in our study were functionalized with hexamethylenediamine, according to the procedure described in previous works (Bourlinos et al, 2003;Pavlidis et al, 2010a).…”

“…Hydrolases were non-covalently immobilized on carbon-based nanomaterials by physical adsorption, using a similar procedure as proposed in a previous work (Pavlidis et al, 2010a). In a typical procedure, 5 mg of nanomaterials in 10 mL of phosphate buffer (50 mM, pH 7.5) were sonicated approximately for 30 min.…”

“…activity of the immobilized enzymes (Pavlidis et al, 2010a). For instance, graphene oxide (GO), a graphite derivative decorated with abundantly with epoxide, carboxylic and hydroxyl groups, was recently used as an efficient immobilization matrix, due to its unique chemical and structural properties (Zhang et al, 2010).…”

Magnetic Microreactors with Immobilized Enzymes—From Assemblage to Contemporary Applications

“…For example, different nanoscale supports have been found to reduce diffusion limitations, enhance biocatalytic efficiency, and increasing the enzyme loading given the superior surface area per mass unit. Nanomaterials are wisely designed to enable long-term storage and recycling stability of the immobilized biocatalyst, while their unique physical and chemical properties create a favorable microenvironment for optimal enzymatic efficiencies [16,17].…”