For the cultivation of recombinant strains of E.coli
FORMULA IN g/l
| Tryptone 20 || Yeast Extract 5 |
| Potassium Chloride 0.186 || Sodium Chloride 0.5 |
| Magnesium Chloride 0.95 || Final pH 7.0 ± 0.2 at 25°C |
Suspend 26.6 grams of the dehydrated medium in one liter of distilled water. Mix well. Heat with frequent agitation until complete dissolution. Sterilize in the autoclave at 121 °C for 15 minutes. Store at4°C. The color of the prepared medium is amber.
This is a nutrient rich medium for the preparation and transformation of competent cells. The transformation requires perforation of the bacteria to allow the introduction of alien DNA inside the cell. In order to survive this process the competent cells need an isotonic rich medium. SOB medium is used in the final stage of the transformation and it can be prepared by adding aseptically 20 ml of a sterile 20% glucose solution to the sterile medium. This addition supplies a carbon and energy source that E. coli uses to repair the perforation as well as for replication.
The following results were obtained in the performance of the medium from type cultures after incubation at a temperature of 35ºC ± 2ºC and observed after 18-24 hours
| Microorganisms || Growth |
| Escherichia coli ATCC 53868 || Good |
The condese protocols from molecular cloning a laboratory manual / Josep Sambrook, David W .Russell.
Store the sealed bottle containing the dehydrated medium at 2 to 25°C. Once opened and recapped, place the container at the same storage temperature protected from moisture and light. The dehydrated medium should be homogeneous, free flowing and beige in color. If there are any changes physically, discard the medium.
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