SOB

Super Optimal Broth - A rich medium for cell growth

• 0.5% (w/v) yeast extract
• 2% (w/v) tryptone
• 10 mM NaCl
• 2.5 mM KCl
• 20 mM MgSO₄

Per liter:

• 5 g yeast extract
• 20 g tryptone
• 0.584 g NaCl
• 0.186 g KCl
• 2.4 g MgSO₄

• Some formulations of SOB use 10 mM MgCl₂ and 10 mM MgSO₄ instead of 20 mM MgSO₄.
• Adjust to pH 7.5 prior to use. This requires approximately 25 ml of 1M NaOH per liter.

SOC

Super Optimal broth with Catabolite repression

If you need SOC, just add glucose to a final concentration of 10mM (3.603g in a litre). This is good recovery medium for the chemically competent cells transformation protocol.

NOTE: Do not autoclave SOC as the glucose can react with the peptides - use filter sterilisation instead!