Effect of polymer support functionalization on enzyme immobilization and catalytic activity

Abstract

Two enzymes, laccase and peroxidase, were immobilized on chloromethylated styrene-divinylbenzene copolymers supports functionalized with phosphonates ((RO) 2 PO) or mixed ammonium and phosphonium groups (N + R 3 Cl -, P + Ph 3 Cl -). Phosphonates groups and quaternary ammonium salts were grafted on the "gel-type" copolymer by Michaelis-Becker polymer analogue reaction. Mixed polymer-supported ammonium and phosphonium salts were obtained by transquaternization of the ammonium groups to phosphonium group. The degrees of functionalization for obtained polymers were relatively high ensuring a sufficient concentration of active centers per unit mass of the copolymer. The obtained materials were characterized by thermal analysis, FTIR spectroscopy and SEM microscopy. The effects of OR1 and R2 radicals from phosphonate and respectively ammonium groups, as well as those of glutaraldehyde utilization on the immobilization yield and the catalytic properties of the supported enzymes were indicated. The activity of enzymes increased after immobilization and high immobilization yield was obtained for all the samples. The higher interaction of enzymes with support was indicated for mixed ammonium and phosphonium functions. A higher catalytic activity was obtained for peroxidase in oxidation of phenol and laccase in oxidation of anisole. The low effect of glutaraldehyde on enzyme activity reveals the strong interaction of enzyme with the polymer support, respectively with the functional groups.

Driving Immobilized Lipases as Biocatalysts: 10 Years State of the Art and Future Prospects

“…29 Organic supports, on the other hand, especially polymers, are able to facilitate covalent binding without cross-linking agents due to a large number of functional groups. 42 Besides that, these kinds of supports show high protein affinity, reducing possible negative effects of the lipase immobilization process. Among synthetic polymers, it is important to highlight poly(vinyl alcohol) (PVA), 43 polystyrene (PS), 44 poly(methyl methacrylate) (PMMA), 45 and polyurethane (PU), 46,47 whereas for biopolymers it is possible to cite collagen, 48 cellulose, 49 carrageenan, 50 chitosan, 51 and alginate.…”

“…Organic supports, on the other hand, especially polymers, are able to facilitate covalent binding without cross-linking agents due to a large number of functional groups . Besides that, these kinds of supports show high protein affinity, reducing possible negative effects of the lipase immobilization process.…”

“…Covalent bonding is the usual technique of irreversible enzyme immobilization, and this method consists of the formation of covalent bonds between enzyme and support material . These interactions involve side chain amino acids, such as lysine, cysteine, aspartic, and glutamic acids and several functional groups like the carboxyl group, amino group, epoxy group, indole group, phenolic group, sulfhydryl group, thiol group, imidazole group, and hydroxyl group, which are not essential for the catalytic activity of enzyme. , Compared with immobilization by adsorption, covalent immobilization exhibits, in general, some superiority since the enzyme can remain on supports under strict conditions and even be used in any reaction media. , …”

“…21,28 Compared with immobilization by adsorption, covalent immobilization exhibits, in general, some superiority since the enzyme can remain on supports under strict conditions and even be used in any reaction media. 42,58 Covalent bonding makes a robust support−enzyme link, which may ensure the enzyme is tightly fixed, preventing enzyme release (protein contamination of product) into the reaction media and, consequently, affording more reuse cycles. Covalent bonding makes it possible to submit the immobilized lipase to unfolding/refolding reactivation strategies without risk of lipase desorption, making it unnecessary to discard either lipase or support.…”