Non-covalent and covalent immobilization of Candida antarctica lipase B on chemically modified multiwalled carbon nanotubes for a green acylation process in supercritical CO2

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.

Nanobiocatalysts for Biodiesel Synthesis through Transesterification—A Review

“…The advantages of this type of immobilization included high reusability potential of the NBCs owing to the extremely high stability because of the formation of covalent bonds. Thermal stability as well as the half-life period of the lipase was also found to be highly effective in case of this type of immobilization [75].…”

Lipase‐Catalyzed Synthesis of Anthrone Functionalized Benzylic Amines via a Multicomponent Reaction in Supercritical Carbon Dioxide

“…Vigolo et al. utilized Cal‐B immobilized on carbon nanotubes for efficient acylation in scCO 2 [26] . In 2019, our group documented a facile aza‐Michael addition reaction of amines with acrylates in scCO 2 , and only 1,4‐addition occurred without aminolysis [27] .…”

“…[25] Vigolo et al utilized Cal-B immobilized on carbon nanotubes for efficient acylation in scCO 2 . [26] In 2019, our group documented a facile aza-Michael addition reaction of amines with acrylates in scCO 2 , and only 1,4-addition occurred without aminolysis. [27] These reports encourage us to further expand the application of scCO 2 as a reaction medium in enzymatic promiscuous reactions, such as lipase-catalyzed MCRs.…”

Facile Cellulase Immobilisation on Bioinspired Silica

“…As far as the covalent bonding is concerned, bifunctional coupling agents are used to tether enzymes on supports [23,24]. Concerning the non-covalent bonding, electrostatic interactions, which depend on the charge of the support and the isoelectric point of the enzyme [25][26][27][28], give rise to weak bonds between the support and the enzyme.…”