Immobilization, tailoring enzymes

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. 

Immobilization is often suggested as a method of tailoring enzymes for more efficient industrial use. In the case of glucoamylase very superior properties would have to be obtained to warrant immobilizing the enzyme due to its relatively low cost in the soluble form. Some of the potential benefits would be logistic... 

Examples of immobilized biocatalysts. Enzyme immobilization clearly imparts many benefits to biocatalysts. A primary advantage is the opportunity to tailor an immobilization matrix for a specific application, use, or set of conditions. Such a process has been, and continues to be, undertaken for a host of biocatalysts and a broad array of applications. The authors describe herein one instance of adapting immobilization techniques and chemistry to a specific application of biocatalysis. Although the specifics and details of this particular effort may not be applicable to every and all uses of enzyme catalysis, some detail is provided to convey to the reader those issues that need to be considered when one attempts to immobilize enzymes for a particular task. 

A remaining crucial technological milestone to pass for an implanted device remains the stability of the biocatalytic fuel cell, which should be expressed in months or years rather than days or weeks. Recent reports on the use of BOD biocatalytic electrodes in serum have, for example, highlighted instabilities associated with the presence of 02, urate or metal ions [99, 100], and enzyme deactivation in its oxidized state [101]. Strategies to be considered include the use of new biocatalysts with improved thermal properties, or stability towards interferences and inhibitors, the use of nanostructured electrode surfaces and chemical coupling of films to such surfaces, to improve film stability, and the design of redox mediator libraries tailored towards both mediation and immobilization. 

In vitro enzymatic polymerizations have the potential for processes that are more regio-selective and stereoselective, proceed under more moderate conditions, and are more benign toward the environment than the traditional chemical processes. However, little of this potential has been realized. A major problem is that the reaction rates are slow compared to non-enzymatic processes. Enzymatic polymerizations are limited to moderate temperatures (often no higher than 50-75°C) because enzymes are denaturated and deactivated at higher temperatures. Also, the effective concentrations of enzymes in many systems are low because the enzymes are not soluble. Research efforts to address these factors include enzyme immobilization to increase enzyme stability and activity, solubilization of enzymes by association with a surfactant or covalent bonding with an appropriate compound, and genetic engineering of enzymes to tailor their catalytic activity to specific applications. 

Glucose Isomerase. The biggest success story in the enzyme industry has to be glucose isomerase. The very first report of an enzyme that converts glucose to fructose was in 1957 (10). In less than 20 years the enzyme was studied, tailored into a cost effective immobilized form and put into production to make a commodity corn syrup product. In less than 30 years from its first description, it became the largest commercially used immobilized enzyme and responsible for making one of the world s major sweeteners. Since... 

Tailored mesoporous siliceous carriers were prepared in a systematic study of the immobilization of chloroperoxidase from Caldariomyces fumago, an enzyme... 

Owing to the capability of controlled sizes of MPS to tailor different enzymes and/or proteins, MPS is considered to be ideal host for immobilizing biomolecules. Some MPS, such as MSU (Michigan State University) [42], SBA-15 (Santa Barbara Amorphous) [43-46], FSM (folded sheet mesoporous) [47-48], MCM (Mobil Composition of Matter) [49] or other hexagonal mesoporous silicas [50-51], have been successfully used to enhance the direct electron transfer rate and the catalysis toward target molecules. Encapsulation of enzymes and... 

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