SOC medium recipe
A rich recovery medium for E. coli right after transformation, typically 2–3× more efficient than LB.
🧮 Volume calculator
| Component | Amount | Final concentration (1X) |
|---|---|---|
| Tryptone | 2 g | 2% |
| Yeast extract | 500 mg | 0.5% |
| NaCl | 58.4 mg | 10 mM |
| KCl | 18.6 mg | 2.5 mM |
| 1 M MgCl₂ (sterile, added later) | 1 mL | 10 mM |
| 1 M MgSO₄ (sterile, added later) | 1 mL | 10 mM |
| 20% glucose (sterile, added later) | 1.8 mL | 20 mM |
| Water (distilled) | to final volume |
Steps
- Dissolve tryptone, yeast extract, NaCl and KCl; adjust to pH 7.0.
- Make up to volume minus the Mg and glucose, then autoclave (this is SOB).
- After cooling, add sterile MgCl₂, MgSO₄ and glucose.
- Aliquot and store at −20 °C (or 4 °C).
FAQ
SOB vs SOC?
SOC is SOB plus 20 mM glucose.
This is a widely used standard composition. Amounts depend on the hydrate form and purity of your reagents — check the formula weight (FW) on the bottle and follow your institution's safety rules and the manufacturers' instructions.