Hydrophobic adsorption and covalent immobilization of Candida antarctica lipase B on mixed-function-grafted silica gel supports for continuous-flow biotransformations

Abstract

HighlightsPhenyl-/aminoalkylsilane-grafted silica gels were used as supports for CaLB.Adsorption onto mixed-function-grafted silica supports resulted in active CaLB.CaLB adsorption and glutardialdehyde cross-linking resulted in enhanced durability.The novel CaLB biocatalysts were used in kinetic resolutions of a secondary alcohol and an amine.The novel CaLBs were robust biocatalysts in continuous-flow biotransformations. AbstractAdsorption onto solid supports has proven to be an easy and effective way to improve the mechanical and catalytic properties of lipases. Covalent binding of lipases onto the support surface enhances the active lifetime of the immobilized biocatalysts. Our study indicates that mesoporous silica gels grafted with various functions are ideal supports for both adsorptive and covalent binding for lipase B from Candida antarctica (CaLB). Adsorption of CaLB on phenyl-functionalized silica gels improved in particular its specific activity, whereas adsorption on aminoalkyl-modified silica gels enabling covalent binding with the proper reagents resulted in only moderate specific activity. In addition, adsorption on silica gels modified by mixtures of phenyl-and aminoalkyl silanes significantly increased the productivity of CaLB. Furthermore, CaLB adsorbed onto a phenyl/aminoalkyl-modified surface and then treated with glutardialdehyde (GDA) as cross-linking agent provided a biocatalyst of enhanced durability. Adsorbed and cross-linked CaLB was resistant to detergent washing that would otherwise physically deactivate adsorbed CaLB preparations. The catalytic properties of our best immobilized CaLB variants, including temperaturedependent behavior were compared between 0 and 70 °C with those of two commercial CaLB biocatalysts in the continuous-flow kinetic resolutions of racemic 1-phenylethanol rac-1a and 1-phenylethanamine rac-1b.

From Synthetic Chemistry and Stereoselective Biotransformations to Enzyme Biochemistry – The Bioorganic Chemistry Group at the Budapest University of Technology and Economics

“…Ideal properties for immobilization support include chemical and mechanical stability, hydrophilicity, inertness toward enzymes, ease of derivatization, biocompatibility, resistance to microbial attack, and a large surface area. Among the many organic and inorganic supports our group focused mostly on mesoporous silica materials (MPs) for use in enzyme immobilization [39][40][41]. MPs have large surface areas with relatively large-pore diameters (5-100 nm) that match the sizes of the enzymes.…”

Strategies for the one-step immobilization–purification of enzymes as industrial biocatalysts

“…The problem is the necessity of having at least a primary amino group near the area involved in the immobilization., in In a recent paper it has been shown that this may (Figure 17) (Rueda et al, 2014). In other papers, amino-phenyl silicates were used to immobilize the lipases from C. antarctica (form B) (Boros et al, 2013) and Burkholderia cepacia (Abaházi et al, 2014). After adsorption, the immobilized enzymes were treated with glycerol diglycidyl ether to have some enzyme-support crosslinking.…”

“…Immobilization was suggested to proceed via interfacial activation (activity improved after immobilization), and the final covalent attachments improve enzyme stability (Abaházi et al, 2014, Boros et al, 2013 This kind of heterofunctional hydrophobic supports may greatly improve the prospects of using interfacial activation of lipases as a tool to prepare biocatalysts useful under any experimental conditions, using the hydrophobic groups to have the a selective adsorption, and the other groups to transform this in an irreversible immobilization. The change of reversible to irreversible immobilization means that the support cannot be reused, therefore the strategy is only recommended when the improvement in enzyme stability or the prevention of enzyme release to the reaction medium are really relevant.…”

Easy and Simple SiO2 Immobilization of Lipozyme CaLB-L: Its Use as a Catalyst in Acylation Reactions and Comparison with Other Lipases

“…Esters could be obtained with a conversion of 46.8% and enantiomeric excess of product (ee p ) > 99%. 9 Zhang et al 10 immobilized CaLB in ZnO nanowires introduced into macroporous SiO 2 and the supported lipase could be reused fifteen times without significant losses. (R)-2-Octanol acetate was obtained with a conversion of 49.1% and ee p of 99%.…”