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== Summary ==
SOB Medium.  Used in growing bacteria for preparing chemically competent cells

== Ingredients ==
*0.5% (w/v) yeast extract
*2% (w/v) tryptone
*10 mM NaCl
*2.5 mM KCl
*20 mM MgSO<sub>4</sub>

Per liter:
*5 g yeast extract
*20 g tryptone
*0.584 g NaCl
*0.186 g KCl
*2.4 g MgSO<sub>4</sub>

''Note:'' Some formulations of SOB use 10 mM MgCl<sub>2</sub> and 10 mM MgSO<sub>4</sub> instead of 20 mM MgSO<sub>4</sub>.

SOB medium is also available dry premixed from Difco, 0443-17.

Adjust to pH 7.5 prior to use.  This requires approximately 25 ml of 1M NaOH per liter.

==15/10 medium==
Growth of competent TOP10 cells in Example 2 of the Bloom05 patent is performed in 15/10 broth, which is similar to SOB:

* 1.5% yeast extract
* 1% Bacto-Tryptone
* 10mM NaCl
* 2mM KCl
* 10 mM MgCl<sub>2</sub>
* 10 mM MgSO<sub>4</sub>

==Source==
Adapted From:

F. Ausubel et al., ''Short Protocols in Molecular Biology'' (John Wiley & Sons, ed. 4, 1999) pg. A1-36

==Trivia==
SOB supposedly stands for super optimal broth.

[[Category:Protocols]]