LB broth

Notes

• You can purchase LB broth as a pre-mix, or make the formulation yourself from tryptone, yeast extract, and NaCl.

Formulations

Materials

• LB broth premix, or separate components according to the table above.

Protocol

1. Suspend $T$ g of LB pre-mix powder in 1 L of distilled water.
2. Autoclave for 15 minutes at 121°C, 17 psig.

Terrific broth (TB, 500 mL)

Materials

• Terrific broth
• Glycerol

Protocol

1. Add 23.8 g of TB powder to 495 mL of distilled water.
2. Add 5 mL of 40% glycerol.
3. Autoclave for 15 minutes at 121°C, 17 psig.

Common media additives

X-Gal (500X, 20 mg/mL ≈ 50 mM) stock solution

Notes

• X-Gal is light-sensitive, so keep the solution at -20°C in the dark.
• For routine cloning plates, use 40 ug/mL as the final working concentration.

Protocol

1. Dissolve 200 mg of X-Gal in 10 mL of DMSO.
2. Filter-sterilize the solution with a 0.22 μm filter.
3. Make 1 mL aliquots in light-protective containers and store at -20°C.

IPTG (1 M, 1000–10000X) stock solution

Notes

• IPTG is often used at 0.1–1 mM final concentration.
• For routine cloning plates, use 0.1 mM IPTG as the final working concentration.

Protocol

1. Dissolve 2.38 g in 10 mL of distilled water.
2. Filter-sterilize the solution with a 0.22 μm filter.
3. Make 1 mL aliquots and store the solution at -20°C.