TITLE: Lysogeny Broth (LB) medium
AUTHORS: Andreas Sagen

[DESCRIPTION]
Lysogeny broth (LB) is a nutritionally rich medium which is primarily used for the growth of bacteria[1]. The initialism is also commonly, albeit incorrectly, taken to mean Luria broth, Lennox broth, or Luria-Bertani medium. According to its creator Giuseppe Bertani, the abbreviation LB was actually intended to stand for lysogeny broth. The formula of the LB medium was
published in 1951 in the first paper of Bertani on lysogeny[2]. There are several common formulations of LB. Although they are different, they generally share a somewhat similar composition of ingredients used to promote growth, including the following: Peptides and casein peptones, Vitamins (including B vitamins), Trace elements (e.g. nitrogen, sulfur, magnesium) and Minerals.
Sodium ions for transport and osmotic balance are provided by sodium chloride (NaCl). Tryptone is used to provide essential amino acids such as peptides and peptones to the growing bacteria, while the yeast extract is used to provide a plethora of organic compounds helpful for bacterial growth. These compounds include vitamins and certain trace elements.

[BEFORE_START]
Prepare glassware by cleaning it, and ensure that scale is sufficiently calibrated

[GUIDELINES]
Follow step by step, unless stated otherwise. Equipment needed should be standard to a microbiology lab.

[STEPS]
SECTION: 500 mL LB-Lennox (broth) medium
1. All compounds are measured using a high precision analytical scale from powdered compounds. Each compound is measured to within 1% of the target weight. All compounds are mixed in a Duran bottle
SECTION: 500 mL LB-Lennox (broth) medium
1.1. Fill the bottle with 400 mL double-distilled water
SECTION: 500 mL LB-Lennox (broth) medium
1.2. Measure 5000 mg Tryptone, 2500 mg Yeast extract and 2500 mg Sodium chloride

Powdered compounds:
 
 
 
SECTION: 500 mL LB-Lennox (broth) medium
1.3. Add powdered solids into bottle, and use a magnetic mixer with a stir bar to mix for 5 min
SECTION: 500 mL LB-Lennox (broth) medium
1.4. Adjust pH while mixing to pH 6.7 using concentrated sodium hydroxide
SECTION: 500 mL LB-Lennox (broth) medium
1.5. Add distilled water to a total of 500 mL
SECTION: 500 mL LB-Lennox (broth) medium
1.6. Autoclave liquid at 121 °C for 15 min
 

SECTION: 500 mL LB-Lennox (agar) medium
2. All compounds are measured using a high precision analytical scale from powdered compounds. Each compound is measured to within 1% of the target weight. All compounds are mixed in a Duran bottle
SECTION: 500 mL LB-Lennox (agar) medium
2.1. Fill the bottle with 400 mL double-distilled water
SECTION: 500 mL LB-Lennox (agar) medium
2.2. Measure 5000 mg Tryptone, 2500 mg Yeast extract, 2500 mg Sodium chloride and 7500 mg agar

Powdered compounds:
 
 
 
 
SECTION: 500 mL LB-Lennox (agar) medium
2.3. Add powdered solids into bottle, and use a magnetic mixer with a stir bar to mix for 5 min
SECTION: 500 mL LB-Lennox (agar) medium
2.4. Adjust pH while mixing to pH 6.7 using concentrated sodium hydroxide
SECTION: 500 mL LB-Lennox (agar) medium
2.5. Add distilled water to a total of 500 mL
SECTION: 500 mL LB-Lennox (agar) medium
2.6. Autoclave liquid at 121 °C for 15 min