Enzymes, immobilized industrial applications

Microcrystalline chitin has been used as a thickening/gelling agent in the binding, stabilizing, and texturing of food [58]. Chitin is widely used to immobilize enzymes and whole cells enzyme immobilization has applications in the food industry, such as clarification of fruit juices and... 

Liese, A. and Hilterhaus, L. (2013) Evaluation of immobilized enzymes for industrial applications. Chem. 

Over the last few decades, intense research in the area of enzyme technology enabled it to facilitate its practical applications. Among them, the novel technological developments in the field of immobilized enzymes offer the possibility of a wider and more economical exploitation of enzymes for industrial applications, waste treatment, medicine, and in the development of devices like biosensor for bioprocess monitoring. ... 

Crosslinked polymers with functional groups have recently been used even more frequently as reagents for the synthesis of low-molecular-weight organic compounds since they are easily separated after conversion and sometimes can easily be regenerated. The immobilization of enzymes by attaching them to crosslinked polymers should also be mentioned. This technique has already found industrial applications. 

Two other immobilized enzymes have reached large scale industrial application penicillin amidase and lipase. 

When immobilized glucose isomerase was introduced in the early seventies, it was believed, that other industrial applications of immobihzed enzymes would soon be found, but this turned out not to be trae. The main limitation to the use of immobilized enzymes is that the substrate has to be soluble and highly purified in order to avoid clogging of the enzyme bed. In the case of glucose isomerase the cost of purifying the syrup (carbon treatment, ion exchange) before the fixed bed isomerase reactors is substantially higher than the enzyme costs. 

Tosa, T. and Shibatani, T. (1995) Industrial Applications of Immobilized Biocatalysts in Japan. Enzyme Engineering XU, edited by M.-D.Legoy and D.N.Thomas. Aimals of the New York Academy of Science, Vol. 750, 364-375. 

W. II. Pitcher Design and Operation of Immobilized Enzyme Reactors. - S. A Barker Biotechnology of Immobilized Multienzyme Systems. - R. A Messing Carriers for Immobilized Biologically Active Systems. -P. Brodelius Industrial Applications of Immobilized Biocatalysts. - B. Solomon Starch Hydrolysis by Immobilized Enzymers. 

Choice of Method. Numerous enzyme immobilization techniques have been described in the literature comprehensive books on this and related subjects, including industrial applications, are available (33—36). The more general techniques and some selection criteria are included herein. 

Because enzymes can be intracellulady associated with cell membranes, whole microbial cells, viable or nonviable, can be used to exploit the activity of one or more types of enzyme and cofactor regeneration, eg, alcohol production from sugar with yeast cells. Viable cells may be further stabilized by entrapment in aqueous gel beads or attached to the surface of spherical particles. Otherwise cells are usually homogenized and cross-linked with glutaraldehyde [111-30-8] to form an insoluble yet penetrable matrix. This is the method upon which the principal industrial applications of immobilized enzymes is based. 

One of the exciting developments associated with ion-selective electrodes has been the fabrication of microelectrodes capable of monitoring an intracellular ion concentration. The history of these developments from the mid-1950s has been reviewed.88 a symposium held in 1996 was devoted to the history of ion-selective electrodes. One paper discussed their development and commercialization,89 another described how the 1970s was the decade in which they really became established,90 a third outlined their industrial applications,91 and a fourth traced the evolution of blood chemistry analyses using them.92 The first attempts to construct biochemical sensors by immobilizing enzymes on electrodes date from the 1960s.93... 

Another limitation in the industrial application of peroxidases is the low stability to H202 (see Chap. 12). Here, an improvement for H202 inactivation through the physical immobilization of CPO on the mesoporous sieve SBA-15 of 130 A for the oxidation of indole to 2-oxoindole has been reported [8]. The performance of the immobilized enzyme was enhanced to that of the native CPO with respect to maximum conversion. According to the authors, the superior performance of... 

Tailoring Opportunities. There are many methods or approaches available to tailor enzyme products. Early in the history of enzyme companies, methods such as source selection, microbial strain selection, growth conditions, media, purification, and recovery systems, were primarily used to make each enzyme preparation unique. Later, immobilization, encapsulation, and chemical modification of the enzyme molecule itself were added as methods of tailoring enzymes to better fit industrial applications. Today, all of these methods are still being used, and now we have added genetic engineering to our tailoring expertises. 

Figure 10-22 Methods of Immobilizing Enzymes. Source From H.H. Weetall, Immobilized Enzymes and Their Application in the Food and Beverage Industry, Process Biochem., Vol. 10, pp. 3-6, 1975.

Weetall, H.H. 1975. Immobilized enzymes and their application in the food and beverage industry. Process Biochem. 10 3-6. 

The immobilization of invertase on aluminium hydroxide (2) was one of the earliest reports of adsorption technology. The use of aminoacylase adsorbed on DEAE-Sephadex for producing L-amino acids from a racemic mixture of their corresponding ethyl esters (4) was the first industrial application of an immobilized enzyme system. The basic disadvantage of this convenient technique is that binding is weak and the enzyme slowly leaches out. However, for many purposes, this slow leakage is not an important handicap. Immobilizing enzymes by adsorption has been extensively reviewed (5, 6, 27). Some special approaches are described (1, 28-30). 

---