Molecular biology media
Luria Broth (Miller’s LB Broth)
For molecular genetics studies in E. coli.
- Cat. No.
- LC-1551
- Category
- Molecular biology media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
Luria Broth (Miller’s LB Broth) is based on LB Medium as described by Miller for the growth and maintenance of E. coli strains used in molecular microbiology procedures.
Key features
Applications
Preparation and recovery of Escherichia coli competent cells.
Industry
Culture media for molecular biology.
Preparation
25 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
These strains are generally derived from E. coli K12, which are unable to produce vitamin B, so this medium is formulated to enhance the growth of nutritionally demanding microorganisms. This strain of E. coli has been further modified through specific mutation to create an auxotrophic strain that is not capable of growth on nutritionally deficient media.
Tryptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly the B-group. Sodium chloride supplies essential electrolytes for transport and osmotic balance.
If desired, aseptically add 10 mL of sterile 20% glucose solution and mix thoroughly for a better growth. Bacteria that contain plasmids tend to grow best in broth that has between 5 and 10 g of salt. Various cofactors may also need to be added to the broth if working with certain types of bacteriophages. For example, bacteriophage lambda requires an excess of magnesium in the broth to properly infect bacteria.
Luria Broth (Miller’s LB Broth) has a different sodium chloride level than other media such as LB Broth (Lennox) (LC-1231) or Luria Broth (Miller’s Modification) (LC-1266). This allows selecting the optimum salt concentration of the medium for a specific strain.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Amber |
| Final pH (25 °C) | 7.0 ± 0.2 |
| Amount per litre | 25 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Sodium chloride | 10 |
| Tryptone | 10 |
| Yeast extract | 5 |
Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.
Preparation and use
Preparation
Suspend 25 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
- Carry out the experimental procedure according to appropriate use or purpose.
- Inoculate and incubate at a temperature of 35 ± 2 °C for 18-24 hours.
Quality control
Microbiological test
Incubation conditions: 35 ± 2 °C / 18-24 h.
Inoculation conditions: productivity qualitative (< 100 CFU).
| Microorganism | Specification |
|---|---|
| Escherichia coliATCC 23724 | Good growth / Turbidity (2) |
| Escherichia coliATCC 33694 | Good growth / Turbidity (2) |
| Escherichia coliATCC 33849 | Good growth / Turbidity (2) |
| Escherichia coliATCC 39403 | Good growth / Turbidity (2) |
| Escherichia coliATCC 47014 | Good growth / Turbidity (2) |
Bibliography
- Atlas, R. M., L.C. Parks (1993). Handbook of Microbiological Media. CRC Press, Inc. London.
- The condensed protocols from molecular cloning: a laboratory manual / Joseph Sambrook, David W. Russell.
What you receive
The product
Shipped under controlled temperature when the product requires it.
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