Glucose Isomerase
Glucose isomerase, known in enzymology as xylose isomerase, catalyses the reversible conversion of D-glucose into D-fructose. It is the enzyme that makes high fructose syrup possible, taking the glucose stream from starch saccharification and shifting it towards an equilibrium mixture of roughly forty two percent fructose, which is then enriched by chromatographic separation to the fifty five percent grade used in soft drinks.
Unlike most food enzymes, glucose isomerase is almost never sold as a soluble powder. It comes as immobilised granules, either cross-linked whole cells or enzyme bound to a carrier resin, packed into fixed-bed columns through which glucose syrup flows continuously for months. Immobilisation is what makes the economics work, since the enzyme is expensive and the reaction converts an enormous tonnage per unit of catalyst.
The granules are light to dark brown, mechanically robust and insoluble, and are used at around 55 to 60 degrees Celsius at pH 7.5 to 8.0 in the presence of magnesium ion, which the enzyme requires. Calcium is a strong inhibitor, so the incoming syrup is softened by ion exchange first. Column productivity decays predictably over the run, and the flow rate is trimmed to hold a constant fructose level until the bed is replaced.
We source bulk Glucose Isomerase from top China manufacturers for our partners. The manufacturer is in Beijing. A smaller requirement can ship in a combined container with other ingredients.
Please send the grade you need, the volume and your destination port, and we will come back with a solution and a price.
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- Function
- Enzyme
Specifications
| Item | Specification |
|---|---|
| Appearance | Light to dark brown insoluble granules |
| Form | Immobilised whole cell or carrier-bound preparation |
| Declared Activity | Standardised to label claim in isomerase units per gram |
| Identification | Conversion of glucose to fructose confirmed by chromatography |
| Operating pH | 7.5 to 8.0 |
| Operating Temperature | 55 to 60 degrees Celsius |
| Fines below 150 micrometres | ≤ 2% |
| Loss on Drying | ≤ 10.0% |
| Residual Glutaraldehyde | ≤ 10 mg/kg |
| Heavy Metals (as Pb) | ≤ 30 mg/kg |
| Lead | ≤ 5 mg/kg |
| Arsenic | ≤ 3 mg/kg |
| Total Plate Count | ≤ 50,000 cfu/g |
| Salmonella | Absent in 25 g |
Common Markets Grades
Glucose isomerase is traded as a single functional article: immobilised granules for fixed-bed operation. Grades differ by the immobilisation chemistry and by the productivity guarantee, expressed as kilograms of dry substance fructose syrup produced per kilogram of enzyme over the life of the bed, and by the declared initial activity in the producer's own isomerase units per gram.
Particle size distribution and mechanical strength are specification items in their own right, because fines cause pressure drop across a deep bed and shorten the run. Products are offered with different thermal stability profiles, allowing the plant to trade a higher operating temperature and throughput against a shorter bed life. Soluble laboratory grades exist as research reagents but have no place in production.
Applications
- High fructose corn syrup manufacture, isomerising the glucose stream from starch saccharification to a fructose-bearing syrup
- High fructose syrup from wheat, rice, cassava and other starch sources where maize is not the local feedstock
- Crystalline fructose production, supplying the enriched fructose stream that feeds the crystallisation train
- Beverage sweetener supply, since the fifty five percent fructose grade is the standard sweetener in carbonated soft drinks
- Bakery and confectionery syrups, where isomerised syrups hold moisture and brown in a way that glucose alone does not
- Isomerised syrups for canning and preserves, providing sweetness with reduced crystallisation risk
- Rare sugar production, where related isomerases and epimerases derived from the same technology produce allulose and tagatose
- Research and analytical work on carbohydrate isomerisation, in soluble reagent form
China Manufacturers of Glucose Isomerase
Top Glucose Isomerase manufacturers in China.
Company names and logos are the property of the manufacturers themselves. They are listed here because our own directory records them as producing this ingredient. A listing is not an endorsement by them, and we do not represent them or speak on their behalf.
Regulatory Status
In the United States insoluble glucose isomerase enzyme preparations are affirmed as generally recognised as safe under 21 CFR 184.1372, which covers the immobilised preparations derived from the recognised production organisms and their use in converting glucose to fructose. The regulation also sets the requirement that the immobilised material be handled so that the carrier and cross-linking agents do not migrate into the syrup, and residues of the immobilisation chemicals are controlled on that basis.
In the European Union glucose isomerase is a food enzyme under Regulation (EC) No 1332/2008, with dossiers assessed by the European Food Safety Authority ahead of entry onto the Union list, and no E number applies to the enzyme. Isoglucose production in the European Union has historically been subject to separate agricultural market rules rather than food safety rules. The Joint FAO/WHO Expert Committee on Food Additives has evaluated immobilised glucose isomerase preparations and publishes identity and purity specifications alongside its general specifications for enzyme preparations used in food processing.
Manufacturing Process
The enzyme is produced by submerged fermentation of Streptomyces, Actinoplanes or Bacillus strains selected for high intracellular isomerase. A working cell bank is grown through seed stages into a stirred aerated fermenter charged with a carbohydrate source, an organic nitrogen source and mineral salts including magnesium, and the culture is held under controlled temperature, pH and dissolved oxygen until enzyme content peaks. Because the enzyme is intracellular, the biomass rather than the broth is the product.
Cells are harvested by centrifugation or membrane filtration and the enzyme is fixed in place rather than extracted. In the whole-cell route the harvested biomass is cross-linked with glutaraldehyde and a polymeric binder, extruded or granulated, dried and sieved to a controlled particle size. In the carrier-bound route the enzyme is released by cell disruption, clarified, and adsorbed or covalently coupled to an anion exchange or polymer carrier before drying. Finished granules are assayed for initial activity and for mechanical strength, then packed in sealed drums for loading into the column.
