Notes
- Super Optimal Broth (SOB) is a common bacterial growth medium used for Escherichia coli. Especially useful for assisting in recovery following transformation. The post-autoclave addition of MgCl₂ makes it slightly more difficult to prepare than LB media which is more routinely used.
Source
Standard lab protocol.
Materials
| SOB Medium | 1 L | M |
|---|---|---|
| Yeast Extract | 5.0 g | – |
| Tryptone | 20.0 g | – |
| 250 mM KCl mw = 74.5 g/mol 4.6 g/250 mL dH₂O | 10.0 mL | – |
| NaCl | 0.5 g | – |
| ddH2O | to 1 L | – |
Method
- Combine in 900 mL of ddH2O.
- Adjust to pH 7.0 with 1M NaOH or 1M KOH.
- Add dH₂O to final volume.
- Autoclave and allow to cool to <60°C.
- If sealed, can be stored at room temperature for some time.
- Add 5 mL of sterile 2 M MgCl2 (M.mass: 95.2 g/mol, 47.6 g/250 mL dH₂O) before use.
