Dehydrated culture media
Nitrate Broth
For the test of nitrate utilization.
- Cat. No.
- LC-1281
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
- Also available
- Ready-to-use medium, 1 format (LC-4005)
Nitrate Broth, combined with the appropriate reagents, is used to confirm the utilization of nitrate.
Key features
Applications
Confirmation of enterobacteria.
Industry
Food.
Preparation
21 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
Nitrate reduction has been extensively studied in bacteria due to its significance in the global nitrogen cycle. Denitrification removes nitrate, an accessible nitrogen source for plants, from the soil and converts it to N₂, a much less tractable source of nitrogen that most plants cannot use. Some bacteria, as the Enterobacteriaceae group, are capable of using nitrate as their terminal electron acceptor. Nitrite, the product of nitrate reduction, is still a highly oxidized molecule and can be fully reduced to nitrogen gas. There are microorganisms that are able to reduce nitrate to nitrogen gas.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Amber |
| Final pH (25 °C) | 7.2 ± 0.2 |
| Amount per litre | 21 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Beef extract | 5 |
| Meat peptone | 10 |
| Potassium nitrate | 1 |
| Sodium chloride | 5 |
Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.
Preparation and use
Preparation
Suspend 21 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Dispense into appropriate containers and sterilize in autoclave at 121 °C for 15 minutes.
Instructions for use
This medium is used from pure cultures. Inoculate and incubate at 37 ± 2 °C for 24 hours and add the Griess-Ilosvay reagent to observe nitrite production. Nitrite reacts with Griess-Ilosvay reagent producing a red color. Gas production can be observed by adding a Durham tube to each tube.
Quality control
Microbiological test
Incubation conditions: 37 ± 2 °C / 24 h.
| Microorganism | Specification | Characteristic reaction |
|---|---|---|
| Salmonella typhimuriumATCC 14028 | Good growth | Positive nitrate, no gas formation |
| Escherichia coliATCC 25922 | Good growth | Positive nitrate, no gas formation |
| Pseudomonas aeruginosaATCC 27853 | Good growth | Positive nitrate, gas formation |
| Enterococcus faecalisATCC 33186 | Moderate growth | Negative nitrate, no gas formation |
Bibliography
- Finegold, S.M., Sutter, V.L.; Ahebery, H.R.; Rosenblatt, J.E.: Isolation of Anaerobic Bacteria. Man. Clin. Micro. Biol. 2nd ed. 1974, 365:375.
What you receive
The product
Shipped under controlled temperature when the product requires it.
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