Biocomposite immobilized enzyme

Although the catalysts do not interfere with each other, the immobilization process resulted in higher yields and ees than with the raw enzyme the initial activity was over five times greater. Additionally, the biocomposite with enzyme was able to be recycled and maintained its activity, which demonstrates the utility of such an immobilization system for potential cascades with mutually interfering catalysts. 

Novozym 435 is already a famous biocomposite containing Candida antarctica lipase B (CAL-B) as the bioactive part. Novozym 435 is commercially available immobilized enzyme with CAL-B physically adsorbed on a macroporous resin of poly(methylmethacrylate) [82]. The enzyme versatility and the substrate affinity recommended Novozym 435 for many applications, including the biomass valorization. An example is the production of the fatty acid esters used as emollient in the cosmetic industry (ex. myristyl myristate) [83,84],... 

Enzyme biocomposites can also be designed without the participation of any solid support [108,109]. Such carrier-free immobilized enzymes can be prepared by direct cross-linking of the protein molecules in different physical states (e.g., dissolved, crystalline, spray-dried, or physically aggregated enzymes) leading to various structures [110]. 

Coradin T, Coupd A., Livage J. Interactions of bovine serum albumin and lysozyme with sodium silicate solutions. Colloid Surf. B Biointerf. 2003 29 189-196 Coradin T, Livage J. Mesoporous alginate/silica biocomposites for enzyme immobilization. C.R. Chimie 2003 6 147-152... 

FIGURE 5.6 Schematic representation of the immunosensor based on a Protein A-GEB biocomposite as a transducer, (a) Immobilization of RlgG on the surface via interaction with Protein A, (b) competitive immunoassay using anti-RIgG and biotinylated anti-RIgG, (c) enzyme labeling using HRP-streptavidin and (d) electrochemical enzyme activity determination. (Reprinted from [31] with permission from Elsevier.)... 

The preparation of dendrimer biocomposite-modified electrode is the primary step in the development of biosensors. Appropriate strategies have been formulated to prepare stable and highly reproducible dendrimer-modified surfaces. Immobilization of biomolecules like enzymes, proteins and other suitable ligands on the dendrimer-modified electrode with extended lifetime is very important. Some general procedures adopted for the preparation of dendrimer biocomposite-modified surfaces for electrochemical biosensing are described below. Some of the unique procedures developed by various authors are elaborated later during the discussion of the performance of biosensors. 

Nanomaterials are a new class of research material that have been tested for enzyme immobilization. Sawicka et al. measured urea concentration by using nanocomposite fibers of urease and polyvinylpyrrolidone (PVP) [146]. Biocomposite nanotibers were prepared by electrospinning a solution in which urease and PVP were dissolved, leading to improvement in response time and sensitivity. 

Christakopoulos and Sheldon groups reported feruloyl and acetylxylan esterases enzymes immobilized following the CLEA biocomposites concept. 

The lactose conversion into various derivatives has been achieved using (3-galactosidase immobilized in an ionic liquid-cellulose film [127]. Enzyme was immobilized via GA approach involving the pre-activation of the supported film. This biocomposite architecture allowed to preserve around 60% of the initial -galactosidase activity. The lactose derivatiza-tion was performed in a batch system, where the biocatalyst was repeatedly used for 16 reaction cycles without any drastic decrease of the enzyme activity [127]. 

Another interesting strategy to combine an enzyme and an ionic liquid in a biocomposite configuration was reported by Vaultier et al [128]. Cellulase was immobilized onto a polymeric support (Amberhte XAD4) coated with a hydrophobic ionic liquid ([N jJ [NTfJ) and tested in saccharification of IL-dissolved cellulose. The presence of amberhte as a cover avoided the deactivation of the cellulose in the hydrophiHc medium [128]. 

A facile enzymatic polymerization protocol for preparing poly(thio-phene-3-boronic acid biocomposites was established (13BB41). The biocomposites were monitored for mono-/bi-enzyme immobilization and amperometric biosensing. 

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