Abstract Candida antarctica B lipase (CAL-B) was immobilized on purified and functionalized multiwalled carbon nanotubes (MWCNTs). Both immobilization routes, physical adsorption and covalent bonding, were investigated. MWCNT functionalization by a… Click to show full abstract
Abstract Candida antarctica B lipase (CAL-B) was immobilized on purified and functionalized multiwalled carbon nanotubes (MWCNTs). Both immobilization routes, physical adsorption and covalent bonding, were investigated. MWCNT functionalization by a non-aggressive oxidation by potassium permanganate led to an interesting balance between the hydrophilic and the hydrophobic areas of the MWCNT surface; the former being responsible of the good dispersion of MWCNTs in water and the latter having a favorable affinity with CAL-B. The enzyme loadings reached were significant: around 16 wt. % and 21 wt.% for non-covalent and covalent immobilization, respectively. The enzymatic activity was studied with the reaction of O-acylation of geraniol into geranyl acetate by CAL-B in supercritical CO2. Even if a decay in synthesis of geranyl acetate was observed over cycling for both CAL-B@MWCNT catalysts, it was demonstrated that the regioselectivity of CAL-B was unchanged through immobilization on the MWCNT surface for both routes. Interestingly, it was shown that a fully green enzymatic process can be achieved with these prepared CAL-B@MWCNT biocatalyst. Such approach could be transferred to other support/enzyme systems for developing new eco-friendly synthesis processes.
               
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