GLUCOSE ISOMERASE FROM STREPTOMYCES OLIVACEUS

CAS: 977078-16-2 ENZYME

Glucose isomerase from Streptomyces olivaceus is a microbial enzyme preparation used to catalyze the isomerization of glucose to fructose in industrial food processing, notably for high fructose syrups.

What It Is

Glucose isomerase from Streptomyces olivaceus is an enzyme preparation derived from a nonpathogenic microbial source that functions to catalyze the reversible conversion of glucose to fructose. It is classified functionally as an enzyme, and commercially prepared forms are often immobilized on carriers to facilitate use in industrial processes. This enzyme is recognized by FDA inventories under the CAS number 977078-16-2 and is identified in regulatory listings such as 21 CFR 184.1372 for enzyme preparations affirmed as generally recognized as safe for direct use in food processing. The term "glucose isomerase" can also be encountered as "xylose isomerase," reflecting the same catalytic activity and broad taxonomic applications in microbial fermentation and food manufacturing. The enzyme’s basic technical role is to catalyze the isomerization of D-glucose into D-fructose by facilitating structural rearrangement without altering the components’ elemental composition. This enzymatic activity underlies its primary industrial deployment in sweetener manufacture, where fructose-rich syrups are produced from starch-derived glucose streams.

How It Is Made

The production of glucose isomerase from Streptomyces olivaceus involves controlled microbial fermentation processes using a pure culture of the Streptomyces organism. During fermentation, the microorganism expresses the glucose isomerase enzyme naturally, after which the enzyme is harvested and processed to produce a stable preparation for food applications. Common industrial approaches include immobilizing the enzyme on solid carriers, which enhances its operational stability and enables reuse in continuous reactors. The immobilization process typically involves crosslinking with inert materials to prevent enzyme solubilization during use. After immobilization and formulation, preparations are tested to meet general specifications for food enzyme preparations, such as those outlined in compendia like the Food Chemicals Codex. Key manufacturing considerations include maintaining fermentation purity, controlling growth conditions to maximize enzyme yield, and ensuring that byproducts or fermentation residues meet safety standards. The manufacturing description emphasizes generic process steps and does not describe specific proprietary techniques, which are typically confidential to individual producers.

Why It Is Used In Food

Glucose isomerase from Streptomyces olivaceus is used in food manufacturing primarily to convert glucose into fructose due to the higher sweetness and functional properties of fructose relative to glucose. In the production of high fructose corn syrup and related sweeteners, this enzyme facilitates efficient biocatalysis under conditions of moderate temperature and pH, avoiding the formation of undesirable byproducts that can occur with nonenzymatic chemical conversions. By enabling the production of fructose-enriched syrups, manufacturers can tailor sweetness profiles and functional attributes for diverse food applications, including beverages, baked goods, and confections. The immobilized enzyme systems are particularly valuable because they can be reused in column reactor configurations, increasing process efficiency and reducing costs in large-scale operations. Use in food processing is grounded in technological and functional reasons rather than nutritional enhancement, focusing on utility in sweetener manufacturing and broader carbohydrate processing.

Adi Example Calculation

Because glucose isomerase preparations from Streptomyces olivaceus are used as processing aids and not directly consumed at measurable levels in finished foods, specific numeric acceptable daily intake values are not established by JECFA or other authorities. Therefore, an illustrative calculation of intake using a hypothetical body weight does not apply in this context. Instead, regulatory guidance emphasizes that use under conditions of good manufacturing practice and removal of immobilized enzyme residues during processing minimizes dietary exposure.

Safety And Health Research

Safety evaluations for glucose isomerase focus on its use as a processing aid rather than a nutritive component. Historical toxicological studies including subchronic feeding tests in animals have been conducted in support of regulatory evaluations, and results have not indicated compound-related adverse effects under conditions relevant to its intended use in immobilized systems. Conventional safety assessments examine microbial source characterization, enzyme purity, absence of toxic metabolites, and potential for allergenicity, among other endpoints. Because the enzyme typically remains immobilized and is largely removed during purification of final syrup products, dietary exposure to the intact enzyme is minimal. Regulatory assessments consider the totality of evidence from fermentation source safety, manufacturing controls, and residue analyses in finished food ingredients. As a result, regulatory authorities generally consider glucose isomerase safe for its intended technical use in food processing when used in accordance with good manufacturing practices.

Regulatory Status Worldwide

In the United States, glucose isomerase from Streptomyces olivaceus is listed in the FDA substance inventory and affirmed as generally recognized as safe (GRAS) under 21 CFR 184.1372 for insoluble enzyme preparations used in food processing, indicating it may be used under conditions of good manufacturing practice in products such as high fructose corn syrup. FDA approval is reflected in this specific Code of Federal Regulations listing. In international contexts, evaluations by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) include a monograph for glucose isomerase from Streptomyces olivaceus, and the committee historically established an acceptable status for this enzyme preparation. However, JECFA’s ADI or numeric intake guidance for this specific enzyme preparation is not specified, indicating a technical regulatory conclusion rather than a quantified daily intake limit. Other regulatory bodies may consider similar enzyme preparations under their respective food additive or processing aid frameworks, recognizing the technological role of glucose isomerase and its use in carbohydrate processing under proper safety assessments.

Taste And Functional Properties

From a sensory perspective, glucose isomerase itself does not contribute a distinct taste since it is an enzyme and not a flavor compound. Its functional properties lie in its catalytic ability to convert D-glucose to D-fructose, a sugar that is perceived as sweeter than glucose. This conversion enhances the sweetness of syrups without adding additional sugar mass, enabling formulators to achieve desired sweetness levels with potentially smaller quantities of syrup. Functional attributes of glucose isomerase preparations include stability under specific pH and temperature ranges common in industrial reactors and resistance to inactivation over extended use when immobilized. Enzyme formulations are designed for operational performance rather than sensory contributions, and when used appropriately in processing, residual levels in finished foods are minimal. Because it acts on sugar substrates rather than directly on flavor components, its contribution to final taste profiles is mediated by the increased fructose content it helps create, rather than by imparting its own sensory properties.

Acceptable Daily Intake Explained

An acceptable daily intake (ADI) represents a regulatory assessment concept indicating the amount of a substance that can be consumed daily over a lifetime without appreciable risk, based on toxicological data and safety factors. For glucose isomerase from Streptomyces olivaceus, regulatory evaluations have historically characterized it as acceptable for use in food processing, but numeric ADI values are not specified by JECFA or other authorities in the absence of direct intake concerns due to minimal dietary exposure. This reflects the technical nature of enzyme use and the efficiency of downstream purification steps that limit residual enzyme levels in finished products. Understanding ADI in this context helps clarify that regulatory acceptance is tied more to process safety and good manufacturing practice than to establishing a consumer intake threshold.

Comparison With Similar Additives

Compared with other food enzyme preparations such as amylases and proteases, glucose isomerase serves a specialized catalytic role in carbohydrate conversion rather than broad substrate breakdown. Amylases, for example, catalyze starch digestion into smaller sugar units and are used in baking and brewing, while proteases hydrolyze peptide bonds in proteins for diverse applications. Lactase is another enzyme preparation used to hydrolyze lactose in dairy products for lactose-intolerant consumers. Unlike enzymes added for direct nutritional or digestibility purposes, glucose isomerase’s primary function is industrial carbohydrate conversion with limited residual presence in final foods. Each enzyme category has its own regulatory evaluation and application context, but all are assessed for safety based on source organism, manufacturing controls, and intended use.

Common Food Applications Narrative

In modern food manufacturing, glucose isomerase from microbial sources like Streptomyces olivaceus is an integral component of processes that yield fructose-enriched syrups used across a wide array of food categories. These enzyme-mediated conversions underpin the industrial production of sweeteners that find their way into beverages, baked products, cereals, confections, dairy flavors, and other processed foods where sweetness and functional syrup characteristics are desired. While the enzyme itself is not a direct ingredient in consumer-packaged foods, its catalytic action enables the production of ingredients such as high fructose corn syrup variants that are widely used as sweeteners and humectants. Because regulatory frameworks permit its use under good manufacturing practice conditions, food processors can employ glucose isomerase in carbohydrate conversion steps without imposing restrictive limits on usage beyond quality control and enzyme handling procedures. In essence, glucose isomerase plays a behind-the-scenes role in creating sweetening solutions that contribute to the sensory and functional attributes of numerous finished food products without altering the fundamental nature of the foods in which the resulting syrups are incorporated.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 184.1372

EFSA

  • Notes: EFSA evaluations specific to Streptomyces olivaceus glucose isomerase were not found

JECFA

  • Notes: JECFA has not specified numeric ADI values on d monograph

Sources

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