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Thermo Scientific™ Oxoid™ ONPG Disc, 50/pk
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Rapid Diagnostic Disc for Detection of β-Galactosidase Activity in Microorganisms
Specifications:
| Application | Microbiology |
| Storage Temperature | 2-8°C |
| Product Type | Antibiotic Disc |
| Product Brand | Thermo Fisher Scientific™, Oxoid |
| Product Grade | Microbiology grade |
The Thermo Scientific™ Oxoid™ ONPG Disc (DD0013T) is a ready-to-use diagnostic reagent for the rapid detection of β-galactosidase enzyme activity in bacterial cultures. Each disc is impregnated with O-nitrophenyl-β-D-galactopyranoside (ONPG) in phosphate buffer, providing a simple and qualitative method to confirm β-galactosidase-positive organisms within minutes.
Upon enzymatic hydrolysis of ONPG by β-galactosidase, a distinct yellow color change is produced, indicating a positive result. This test is valuable for differentiating lactose-fermenting bacteria, such as Escherichia coli, from slow or non-lactose fermenters, including Shigella and Salmonella species.
Key Features
- Rapid detection of β-galactosidase enzyme activity.
- Qualitative colorimetric test — positive results indicated by a yellow color change.
- Convenient disc format impregnated with ONPG substrate.
- Simple to use — designed for use with pure, agar-grown cultures.
- Professional laboratory diagnostic tool for microbial differentiation.
- Non-automated, ready-to-use reagent discs for culture-based workflows.
Intended Use
The Oxoid™ ONPG Diagnostic Discs are used in microbiology laboratories for the detection of β-galactosidase activity in bacteria. The presence of this enzyme is demonstrated by a yellow color reaction when ONPG is hydrolyzed. The device provides a qualitative, manual diagnostic result, aiding in microbial identification and differentiation.
For professional laboratory use only. Not for self-testing.
Principle of the Test
- Each disc is impregnated with O-nitrophenyl-β-D-galactopyranoside (ONPG), a chromogenic substrate.
- When the enzyme β-galactosidase is present in the bacterial sample, it hydrolyzes ONPG, releasing o-nitrophenol, which imparts a yellow coloration.
- The color change indicates a positive result for β-galactosidase activity.
Applications
- Microbial identification and differentiation based on β-galactosidase activity.
- Confirmation of lactose fermentation in enteric bacteria such as E. coli, Klebsiella, and Enterobacter species.
- Diagnostic microbiology testing in clinical, food, and water analysis laboratories.
- Teaching and demonstration in microbiological enzymatic assays.
Specifications
| Parameter | Details |
|---|---|
| Product Type | ONPG Diagnostic Disc |
| Format | Impregnated disc |
| Active Ingredient | O-nitrophenyl-β-D-galactopyranoside (ONPG) |
| Buffer System | Phosphate buffer |
| Test Type | Qualitative (manual) |
| Detection Principle | Colorimetric (yellow color formation) |
| Storage Temperature | 2°C to 8°C |
| Unit Size | Each |
| Quantity per Pack | 50 discs |
| Catalog Number | DD0013T |
| Intended Users | Professional laboratory personnel |
| Automation Compatibility | Non-automated workflow |
Packaging and Ordering Information
| Catalog Number | Product Description | Pack Size | Storage |
|---|---|---|---|
| DD0013T | Thermo Scientific™ Oxoid™ ONPG Diagnostic Discs | 50 discs | 2–8°C |
Storage and Handling
- Store between 2°C and 8°C in a dry environment.
- Avoid exposure to light and moisture.
- Do not use beyond the expiration date printed on the label.
- Handle using aseptic technique to prevent contamination.
The Thermo Scientific™ Oxoid™ ONPG Disc provides a rapid, reliable, and convenient method for detecting β-galactosidase enzyme activity in bacteria. Designed for use with pure, agar-grown cultures, it delivers qualitative colorimetric results that support accurate microbial differentiation and lactose fermentation studies. Trusted in clinical, industrial, and educational microbiology laboratories, this diagnostic disc is a simple yet powerful tool in enzymatic testing.