SOB

NaCl, 0.5 g

tryptone, 20 g

deionized H₂O, to 950 ml

For solid medium, please see Media Containing Agar or Agarose.

yeast extract, 5 g

Shake until the solutes have dissolved. Add 10 ml of a 250 mM solution of KCl. (This solution is made by dissolving 1.86 g of KCl in 100 ml of deionized H₂O.) Adjust the pH of the medium to 7.0 with 5 N NaOH (approx. 0.2 ml). Adjust the volume of the solution to 1 liter with deionized H₂O. Sterilize by autoclaving for 20 minutes at 15 psi (1.05 kg/cm ²) on liquid cycle. Just before use, add 5 ml of a sterile solution of 2 M MgCl₂. (This solution is made by dissolving 19 g of MgCl₂ in 90 ml of deionized H₂O. Adjust the volume of the solution to 100 ml with deionized H₂O and sterilize by autoclaving for 20 minutes at 15 psi [1.05 kg/cm²] on liquid cycle.)