Immobilization of Enzymes in/on Membranes and their Applications

Abstract

Enzyme membrane reactors (EMRs) are becoming increasingly interesting for application in bioconversion processes in food processing, pharmaceutics, biorefinery and wastewater treatment. Integrating the highly efficient enzymatic reaction with selectable membrane separation technology, the EMRs are able to reduce product inhibition, improve the stability of the enzyme, increase the number of reaction cycles and sustainably separate products from biotransformation solutions. Generally, in EMRs, enzymes can be either free in the solution, immobilized on an additional carrier or immobilized directly in/on a porous structure of the membrane, of which the system with the enzyme immobilized directly in/on the membrane (EIM) is a relatively simple and most widely applied method. The EIM system not only facilitates recycling of the enzymes but also in many cases additionally enhances enzyme properties such as the stability and viability. A membrane with a porous structure is usually considered as a potential carrier for enzyme immobilization. A series of immobilization methods has been developed to fix the enzymes on the membranes. The purpose of this review is to systemically summarize the immobilization methods of enzymes in/on membranes and the applications of the EIM system for biocatalysis.

Flow Biocatalysis: A Challenging Alternative for the Synthesis of APIs and Natural Compounds

“…Examples of such supports are cellulose [97], coconut fibers [98], kaolin [99], molecular sieves [100], silica [101] and agarose [102], which have been utilized in several different physical forms such as monoliths [103], supermagnetic nanoparticles [28,104,105] and hydrogels [106][107][108]. In wall-coated reactors, the enzyme can be immobilized directly on the reactor's walls or on a membrane [109][110][111], whereas in PBR, the supported-enzyme particles are packed in a glass column. It is noteworthy that, in the last year, the first application of "fluid" immobilized enzymes in continuous flow processes was reported [112].…”

Electrochemiluminescence Biosensors Using Screen-Printed Electrodes

“…The adsorption and entrapment of enzymes in porous substrates or the confinement of enzymes in semipermeable membranes are the main methods of immobilization by physical retention [ 94 ]. The most popular methods to build biosensors are cross-linking [ 95 ] and entrapment [ 96 ].…”

Enzyme-functionalised, core/shell magnetic nanoparticles for selective pH-triggered sucrose capture

“…Enzyme immobilisation onto supports, such as magnetic nanoparticles, offers a range of advantages, for example, the extension in enzyme stability and protection against degradation, leading to higher resistance to denaturants, temperature changes and organic solvents, it enables repeated use, it optimises and facilitates the separation step, allowing for a quicker recovery of the enzyme, and therefore, reducing operational costs. [43][44][45][46][47][48] The enzyme invertase was used as the basis for the sucrose recognition part of the designed nanomaterial. Invertase (bfructofuranosidase, EC 3.2.1.26) is one of the most studied enzymes and can be described as a highly efficient and specic enzyme for the hydrolysis of sucrose.…”