LB Liquid Media

Equipment & Consumables:

• PPE: Gloves, Lab Coat and Goggles

• Sterile Workspace

• Weighing Scale (accurate to to 0.01g)

  • Weigh boats (or folded paper)

• Autoclave

  • or other method for sterilisation (microwave or pressure cooker)

• Optional: Heated/Stirring Platform

• Optional: pH Meter (recently calibrated)

• Graduated Beaker

• Measuring Cylinder

• 4°C Refrigerator

• 1L ddH20 (MilliQ or RO)

• 10 g Tryptone

• 5 g Yeast Extract

• 10 g NaCl = LB-Miller

  • 5g = LB-Lennox

  • 0.5g = LB-Luria

Protocol:

Recipe for 1 Litre LB-Miller Broth

Note: If using an Autoclave, you want lots of head room. Multiply all values by (x0.4) to fill a 1L bottle to the optimal amount (400mL):

1. Measure out 10g of Tryptone and add it to your bottle.

   • Note: Peptone and Tryptone are interchangeable but will have minor influences on your experiment. Feel free to use one in place of the other, but don't go swapping mid experiment.

2. Measure out 5g of Yeast Extract and add it to your bottle.

3. Measure out 10g of NaCl and add it to your bottle. (LB-Miller)

   • Note: If you plan to use everyday table salt, double check to ensure it doesn't also contain anti-caking agent. This will inhibit bacterial growth.

   • Alternative LB Recipes: 5g NaCl (LB-Lennox), 0.5g NaCl (LB-Luria)

4. Add MilliQ or RO water to make volume up to 1L.

   • Note: It is possible to make LB media with tap water, but keep in mind that the mineral content will start to interfere with your experiments soon. If you don't have access to a water purification system - try hunt down a cheap purification system before it becomes a problem.

5. Tighten the lid of your bottle, then loosen by half a turn.

6. Sterilise 20 minutes/liquid cycle in an autoclave. Or use one of our cheaper sterilisation protocols.

   Consider splitting your 1L of LB-Broth into 200 x 15mL tubes each containing 5mL Broth. Glass bottles are best for this since they are reusable, but be sure to keep those lids loose when sterilising!