ProtocolsRecipesSOB < Lab

---+++ SOB/SOC: Super Optimal Broth

*For SOB:* <br>
%TABLE{}%
|  *200mL*  |  *250mL*  |  *1L*  |  *Final [ ]*  |  *Component*  |
|  1 g  |  1.25 g  |  5 g   | 0.5% | yeast extract | 
|  4 g  |  5 g  |  20 g   | 2.0% | tryptone | 
|  0.12 g  |  0.125 g  | 0.5 g | 10 mM | NaCl |
|  0.037 g*  |  0.042 g*  | 0.186 g | 2 mM | KCl |
|  0.48 g  |  0.6 g  | 2.4 g | 20 mM | MgSO<sub>4</sub> (anhydrous) |

*Don't measure; it's just a pinch.

Adjust to pH 7.5 with 1M NaOH.

Note: 200 ml of SOC makes 25 two-dram vials of 8 ml each.

For 1 L: Add 800 ml of dH<sub>2</sub>O and dissolve components. Adjust to pH 7.5 prior to use with 1 M NaOH (approximately 25 ml). Add dH<sub>2</sub>O to a final volume 1 L. 

Autoclave. 

---++ For SOC (=SOB+glucose)
<b>Bulk scale:</b> Make SOB, except add dH<sub>2</sub>O to a final volume of 960 ml instead of 1 L.  Autoclave. When solution has cooled to 50°C (cool enough to touch with bare hands for a few seconds), add 40 ml of sterile 10% (w/v) glucose. (That's a final concentration of 0.4% glucose or about 20 mM.)

<b>Smaller scale:</b> To achieve a 20 mM concentration of glucose for a known final volume <i>n</i> of SOC, you can calculate the amount of 10% w/v glucose to be added as 0.036<i>n</i>. The amount of SOB to add is then 0.964<i>n</i>. Keep units constant, so if <i>n</i> is in µL, the final amounts will also be in µL and so on.
   * Note: If you have a known volume of SOB <i>x</i> and want to know how much 10% w/v glucose to add to make SOC containing 20 mM glucose, simply divide <i>x</i>/0.964 to get your final volume <i>n</i> and subtract <i>x</i> from <i>n</i> to get the volume of 10% w/v glucose to add.

Generally when making stocks of SOC it is advisable to make smaller volume aliquots rather than larger ones. SOC media is extremely rich and can contaminate easily particularly after glucose is added. Additionally, smaller volumes tend to be pulled from it repeatedly with pipettes, which increases the chances of contamination over time.

*Note:* Some recipes for SOB use 10 mM MgSO<sub>4</sub> and 10 mM MgCl.

---++ Containers
Autoclave the two-dram vials of SOC in the plastic container and store in the cardboard container when dry. Make sure lids are unscrewed prior to autoclaving and screwed shut afterward. The plastic container can have the rack popped out (see image on the right) after autoclaving to dry any water that accumulated at the bottom of the box and avoid the growth of mold and such.
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<img style="border-color: black; border-style: solid; border-width: 1px;" width=300 height=300  src="https://barricklab.org/twiki/pub/Lab/ProtocolsRecipesSOB/IMG_6913.jpg">
<img style="border-color: black; border-style: solid; border-width: 1px;" width=300 height=300  src="https://barricklab.org/twiki/pub/Lab/ProtocolsRecipesSOB/IMG_6912.jpg">
Barrick Lab > ProtocolsMediaRecipes > ProtocolsRecipesSOB
Topic revision: r10 - 2025-07-03 - 16:59:00 - Main.AlexaMorton