Enzyme biocatalysis plays a very relevant role in the development of many chemical industries, e.g., energy, food or fine chemistry. To achieve this goal, enzyme immobilization is a usual pre-requisite as a solution to get reusable biocatalysts and thus decrease the price of this relatively expensive compound. However, a proper immobilization technique may permit far more than to get a reusable enzyme; it may be used to improve enzyme performance by improving some enzyme limitations: enzyme purity, stability (including the possibility of enzyme reactivation), activity, specificity, selectivity, or inhibitions. Among the diverse immobilization techniques, the use of pre-existing supports to immobilize enzymes (via covalent or physical coupling) and the immobilization without supports [enzyme crosslinked aggregates (CLEAs) or crystals (CLECs)] are the most used or promising ones. This paper intends to give the advantages and disadvantages of the different existing immobilization strategies to solve the different aforementioned enzyme limitations. Moreover, the use of nanoparticles as immobilization supports is achieving an increasing importance, as the nanoparticles versatility increases and becomes more accessible to the researchers. We will also discuss here some of the advantages and drawbacks of these non porous supports compared to conventional porous supports. Although there are no universal optimal solutions for all cases, we will try to give some advice to select the optimal strategy for each particular enzyme and process, considering the enzyme properties, nature of the process and of the substrate. In some occasions the selection will be compulsory, for example due to the nature of the substrate. In other cases the optimal biocatalyst may depend on the company requirements (e.g., volumetric activity, enzyme stability, etc).

Potential of Different Enzyme Immobilization Strategies to Improve Enzyme Performance

https://zenodo.org/record/1259717/files/article.pdf

Advances in the Synthesis of Oligonucleotides by the Phosphoramidite Approach

The merging of silicon microfabrication techniques with surface functionalization biochemistry offers new exciting opportunities in developing microscopic biomedical analysis devices with unique characteristics. Micro-mechanical transducers for chemical and biosensing applications represent one possibility. Microcantilevers can transduce a chemical signal into a mechanical motion with high sensitivity. In this review we summarize how cantilever-based sensors can be operated, and their working principle is presented in few selected biosensing experiments which have been performed recently in our groups in the study of biotin–streptavidin and antigen–antibody interactions, and specific surface charge development of organic molecules. We also discuss the advantages of this novel technique as well as its potentials.

Micromechanical cantilever-based biosensors

https://www.cell.com/trends/biotechnology/pdf/S0167-7799(08)00217-5.pdf

Nanoparticles as vehicles for delivery of photodynamic therapy agents

The biotechnological utilization of cheese whey: A review

Publisher Summary This chapter discusses the covalent coupling methods for inorganic support materials. Immobilization by covalent attachment to inorganic supports involves reactions that are similar to the covalent attachment of enzymes to organic supports. Silane coupling and derivatives of alkylamines and coupling techniques are described in the chapter. Silane coupling techniques include alkylamine coupling and organic silanization. Aqueous silanization appears to couple a monolayer of silane across the carrier surface. The organic solvent techniques give higher amine loadings. However, experience has shown that greater carrier durability with slightly lower enzyme loadings are achieved by aqueous silanization. Organic silanization gives much higher loadings of alkylamine than the aqueous method. Derivatives of alkylamines and coupling techniques include alkylamine-coupling isothiocyanate coupling carbodiimide coupling, and triazine coupling.

Covalent coupling methods for inorganic support materials.

Trypsin and papain have been covalently linked to porous glass particles. The resulting insolubilized enzymes show increased thermal stability and can be employed for extended periods of time without loss of activity.

https://science.sciencemag.org/content/sci/166/3905/615.full.pdf

Trypsin and Papain Covalently Coupled to Porous Glass: Preparation and Characterization

Storage stability of water-insoluble enzymes covalently coupled to organic and inorganic carriers

The enzyme β‐galactosidase (lactose) obtained from several microbial sources was immobilized on zirconia‐coated porous glass particles. The immobilized enzymes were characterized by determining pH profiles, kinetic constants, thermal profiles, and operationalhalf‐lives in lactose and whey ultrafiltrate solutions. Studies were carried out on continuous reactor performance, and enzyme requirements for scale‐up were estimated. Lactose or whey hydrolyzed by this technique could find use commercially as a sweetener in a number of dairy products.

Howard H. Weetall

Papers

Covalent coupling methods for inorganic support materials.

Trypsin and Papain Covalently Coupled to Porous Glass: Preparation and Characterization

Storage stability of water-insoluble enzymes covalently coupled to organic and inorganic carriers

The preparation of immobilized lactase and its use in the enzymatic hydrolysis of acid whey

Preparation and characterization of glucose oxidase covalently linked to nickel oxide.