Industrial enzymes apphcation

Immobilized enzymes, 3 670 10 270-272 industrial-scale apphcations of, 10 272 silylating agents and, 22 700—701 Immobilized glucose oxidase, hydrogen peroxide biogeneration for bleaching, 4 65-66... 

The volume of cellulase produced by submerged fermentation is much larger than that produced by soHd culture, which is primarily limited to baking and Asian detergent appHcations. Worldwide consumption of cellulase from submerged fermentation is roughly 23,000 tonnes annually. The sales volume of cellulase is around 125 milHon, which represents over 10% of all industrial enzyme sales. 

In addition to large volume enzyme appHcations, there are a large number of specialty applications for the enzymes. These include use of the enzymes in clinical analytical applications, flavor production, protein modification, personal care products, DNA technology, and in fine chemical production. Unlike bulk industrial enzymes, these enzymes need to be free from side-activities, which require extensive purification process. 

Biomedical Applications. TRIS AMINO is used for a number of purposes in its pure form, it is an acidimetric standard the USP grade can be utilized intraveneously for therapeutic control of blood acidosis TRIS AMINO also is useful in genetic engineering as a buffering agent for enzyme systems, industrial protein purification, and electrophoresis. AMP has found use as a reagent in enzyme-linked immunoassays. The primary appHcation is for alkaline phosphatase assays. 

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

Because enzymes can be intraceUularly 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 appHcations of immobilized enzymes is based. 

Technical Enzymes. When an enzyme is used for a technical appHcation, ie, industrial but nonfood and nonfeed, its regulatory status is determined by its properties as a naturally occurring substance. These properties determine the classification and consequent labeling in accordance with existing schemes for chemicals. It should be noted that enzymes are not Hsted as dangerous chemicals. 

In contrast, amino acid dehydrogenases comprise a well-known class of enzymes with industrial apphcations. An illustrative example is the Evonik (formerly Degussa) process for the synthesis of (S)-tert-leucine by reductive amination of trimethyl pyruvic acid (Scheme 6.12) [27]. The NADH cofactor is regenerated by coupling the reductive amination with FDH-catalyzed reduction of formate, which is added as the ammonium salt. 

The optimization of enzymes strongly depends on the field of appHcation. For industrial applications, high reaction rates, stabiHty under process conditions, and regio- and enantioselectivity are the most important properties of a catalyst, whereas affinity or substrate selectivity are of second order interest for a distinct process to be catalyzed. On the other hand, enzymes with a wide range of activity can be used for the production of several products reducing... 

Enzymes that catalyze addition-elimination reactions, lyases (E.C. class 4) are cofactor independent and suited for cell-free apphcations. Nevertheless, it has proven more economical to use resting cells in large scale industrial applications such as the production of aciylamide (Yamada Tani, 1983). 

Thus the use and practice of biocatalysis at full scale has waxed and waned over the years. In the past, one factor limiting the use of biocatalysis has been the availability of a variety of enzymes and the time taken to refine/evolve enzymes for specific industrial apphcations. Hydrolytic enzymes such as lipases and proteases designed for other industrial uses such as detergents and food processing have always been available in bulk, and indeed used by process chemists. 

Enzymes have had billions of years of evolution in order to sustain hving systems as needed. That these naturally evolved molecules can then accomplish any other task outside their intrinsic requirements is simply fortuitous. It is thus not surprising that the use of enz5nnes for environmental, industrial or biotechnological apphcations is not easily reconcilable with their intrinsic characteristics. 

In the late 1980s, the use of cellulase enzymes began as an alternative to stones. Cellulase gained a foothold in the industry by producing the softness and appearance of jeans washed with pumice stones, but without the problems of stones. The availability of cellulase at costs competitive with stones in early 1990 led to the widespread adoption of cellulase use by the industry. Today, cellulase is used all over the world in this appHcation, sometimes alone and sometimes with some stones present. 

Zhu X, Lewis CM, Haley MC, Bhatia MB, Pannuri S, Kamat S, Wu W, Bowen ARSTG (1997) IBC s 2nd Annual Symposium on Exploiting Enzyme Technology for Industrial Apphcations, Feb 20-21 1997, San Diego USA... 

Two other practical appHcations of enzyme technology used in dairy industry are the modification of proteins with proteases to reduce possible allergens in cow milk products fed to infants, and the hydrolysis of milk with Upases for the development of Hpolytic flavors in speciaUty cheeses. 

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