SOB Medium | 250g

Super Optimal Broth Medium

SOB or its glucose-supplemented version SOC, is often used during the transformation of E. coli competent cells with plasmids (added in transformed cells after heat shock/electroporation).

General description

Hannahan’s Broth (SOB) is a microbial growth medium used for the preparation and transformation of competent cells (E. coli). Casein enzymic hydrolysate and yeast extract supply nitrogenous compounds and growth factors for recombinant Escherichia coli. Potassium chloride and sodium chloride maintain the isotonic condition. Magnesium sulphate is added to the medium as a necessary component for DNA replication.

Application

Hanahan′s Broth is recommended for use in the cultivation of recombinant strains of Escherichia coli. It is suitable for the preparation of competent E. coli., often with the addition of 0.4% dextrose. It has also been used for the preparation of C. necator H16 competent cells. It is suitable for non-selective cultivation of E. coli strains for cloning, DNA plasmid production and production of recombinant proteins.

Features and Benefits

Hannahan′s Broth (SOB) powder provides:

Standard formulation

An inexpensive alternative to liquid

Components

MgSO₄               2.4 g/L

NaCl                   0.5 g/L

KCl                     0.186 g/L

Tryptone            20 g/L

Yeast extract     5 g/L

Preparation

Stir to suspend 28 g powder in 1 L of water. Autoclave for 15 minutes at 121°C to sterilise. Allow to cool before making additions, such as antibiotics (if desired).

Notes

Casein enzymic hydrolysate and yeast extract supply the necessary nitrogenous compounds and growth factors. Potassium chloride and sodium chloride provide an isotonic environment for the cells. Magnesium sulphate aids DNA replication.

pH

6.8-7.2 (2.8% solution)