Glucose isomerase immobilized form

Because glucose isomerase is formed intracellularly in many bacterial strains of commercial interest, some industrial processes have utilized immobilized cells. 

P-amylase, and debranching enzymes. Conversion of D-glucose to D-fmctose is mediated by glucose isomerase, mosdy in its immobilized form in columns. Enzymic degradation of starch to symps has been well reviewed (116—118), and enzymic isomerization, especially by immobilized glucose isomerase, has been fiiUy described (119) (see Syrups). 

A critical consideration in the development of biocatalytic systems is the form in which the enzyme or enzyme system is going to be used. There are two general approaches. One is to use isolated enzymes. If these are inexpensive, they can be used as disposable biocatalysts, as is the case for glucose isomerase, ° which is the key biocatalyst in the production of high-fructose corn syrups from starch, or the lipases and proteases that are present in detergents. Alternatively, if enzymes are expensive to produce, they can be immobilized and used repeatedly by recovering the enzyme particles after each use. 

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... 

The isomerization of the glucose syrup thus obtained was originally also employed in batch reactors using the Mg -containing enzyme glucose isomerase in soluble form, but rapidly evolved to the use of an immobilized enzyme... 

D-Glucose Isomerases. — A description of the commercial use of commercial D-glucose isomerase (D-xylose isomerase), including immobilized forms of the enzyme in conversion of corn syrups to high D-fructose syrups, has been given. 

D-Glucose isomerase has been immobilized with retention of enzymic activity by water soluble carbodi-imide aided reaction with chitosan. By reaction with/adsorption on to a range of new polyphenolic resins, and as Strepto-myces phaeochromogenes cells in fine-particle form using radiation-induced polymerization at low temperatures with previously salted out hydrophilic monomers such as 2-hydroxyethylacrylate and 2-hydroxyethylmethacrylate. ... 

D-Glucose isomerase has continued to be immobilized with retention of activity the large-scale commercial form is available as immobilized Sweet-zyme . In another instance, the enzyme has been fixed to an organism mycelium and as such immobilized by spraying a mixture with gelatin into... 

The purified enzyme is soluble, and so would be difficult to recover from a reaction mixture. It must therefore be made insoluble again, that is to say immobilized, before it is used. A variety of methods are possible, ranging from its adsorption on to bentonite or on to a resin such as a polymethacrylate where it may be cross-linked with glutaraldehyde to form an insoluble matrix (cf. glucose isomerase, section 6.6.1), to its incorporation into fibres of cellulose triacetate. In any of these immobilized forms the amidohydrolase retains much, if not all, of its catalytic activity. The nature of the catalytic reactor depends largely on the form of the immobilized enzyme, but essentially the enzyme replaces the whole E. coli cells of the original process. When the hydrolysis is complete it can be easily recovered from the reaction mixture and re-used in tens, if not hundreds, of reactions. 

D-Glucose Isomerases.—Active immobilized forms of D-glucose isomerase have been obtained by reaction with cyanogen bromide-treated alumina, glass, or titania. ... 

D-Glucose Isomerases.—Attention has been drawn to some of the problems encountered in the enzymic transformation of starch into D-fructose syrups. D-Glucose isomerase has been converted into active immobilized forms by adsorption onto Duolite A7 (a phenol-formaldehyde resin), by entrapment in cellulose fibres, and by adsorption onto the internal surface of controlled-pore alumina. The possibility of using an immobilized form of D-glucose isomerase in the continuous production of D-fructose from D-glucose has been investigated. ... 

The enzyme-catalysed isomerization of D-glucose to D-fructose has attracted a good deal of attention, particularly with the availability of immobilized forms of D-glucose isomerase. The properties of D-glucose isomerase attached to a phenol-formaldehyde resin have been carefully studied the immobilized enzyme possesses sufficient mechanical strength to stand up to the pressures of column flow, is active over broad ranges of temperature and pH, and is not so dependent on Mg + and 00 + ions for activity. An active immobilized form of D-glucose oxidase is also produced by precipitation of the enzyme with concanavalin A this form could be reused without appreciable loss of enzymic activity. ... 

This is an enzyme that catalyzes the conversion of glncose into fructose and, therefore, the key for the production of fructose-containing syrups. Glucose isomerase is produced intracellularly by certain species of microorganisms. Most commercial types are obtained from Actinoplanes and Streptomyces (Hobbs 2003). Glucose isomerase is used almost eutirely in immobilized form. The enzyme is usually attached to an insoluble support, such as diethylaminoethyl (DEAL), cellulose, or alumina, via adsorption. In most conunercial applications, the inunotriUzed enzyme... 

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