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Commonly used bacterial E.coli culture media in microbiology or molecular biology
LB, SOB, SOC, 2x YT, Terrific Broth (TB), and Super Broth (SB)

Commonly used bacterial E.coli culture media

Applications of common bacterial culture media

More information of common bacterial culture media...>

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Bacterial E.coli culture media: LB Miller broth/LB Lennox broth

LB broth is the most commonly used culture medium in molecular biology for E.coli cell culture. Easy to make, fast growth rate of most E.coli strains, readily available and simple compositions contribute the popularity of LB broth. LB broth contains the enzymatic digestion product of casein commonly known as peptone (some vendors term it Tryptone), yeast extract, and sodium chloride. Peptone is rich in amino acids and peptides. Its amino acid and peptide compositions reflect those of casein. In addition to amino acids and peptides, yeast extract also contains nucleic acids, lipids and other nutrients which are needed for bacterial growth. LB can support E.coli growth OD600 2 to 3 under normal shaking incubation condition (250 rpm). The LB Miller Broth and LB Lennox Broth contain higher and lower sodium chloride levels respectively. There are minimal differences between the two formulations in most molecular biology studies with commonly used E.coli strains. Different bacteria strains may require different salt concentrations. The low salt formula is more often used in salt-sensitive antibiotic selections.

Our LB broth is best priced in the industry at 12 bottle packages.

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High salt LB broth/LB medium: LB Miller Broth
1% peptone, 0.5% yeast extract, and 1% NaCl

Product literatures of bacterial E.coli culture medium high salt LB Broth/LB medium

Technical sheet | MSDS

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Low salt LB broth/LB medium: LB Lennox Broth
1% peptone, 0.5% yeast extract, and 0.5% NaCl

Product literatures of bacterial E.coli culture medium low salt LB Broth/LB medium

Technical sheet | MSDS

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Bacterial E.coli culture medium SOB
2% peptone, 0.5% Yeast extract, 10mM NaCl, 2.5mM KCl, 10mM MgCl₂ , 10mM MgSO₄

SOB is another commonly used rich media. It has twice as much peptone compared to LB. It is richer in amino acids and peptides. In addition, it contains magnesium Mg2+ which is required for high density cell growth. SOB can support E.coli growth to OD600 3 to 5 under normal shake flask conditions (250 rpm). It can support cell density to OD600 10 to 15 with increased aeration (350 rpm). E.coli cells growing in SOB will have higher transformation efficiency than those in a LB medium. SOB is commonly used to make high efficiency competent cells.

Product literatures of bacterial E.coli culture medium SOB

Technical sheet | MSDS

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Bacterial E.coli culture medium SOC
2% peptone, 0.5% Yeast extract, 10mM NaCl, 2.5mM KCl, 10mM MgCl₂ , 10mM MgSO₄, 20 mM Glucose

SOC is the same as SOB except it contains 20 mM glucose. Glucose serves as a catabolic repressor in SOC medium. E.coli cells prefer to use glucose as a carbon or energy source. In the presence of glucose, cellular machineries that use other sugars will be repressed. At a concentration of 20 mM or 0.36%, it provides sufficient transcription repression for lacI repressed promoters at low cell density. Expression of recombinant proteins that may adversely affect host cell physiology is repressed. As a result, transformation reactions using SOC to grow the cells for one hour will have higher efficiencies than those using LB. SOC is commonly used in incubation after heat shock in the transformation reaction. When SOC is not available, adding 20 mM glucose to LB or any other commonly used rich media will result in similar transformation efficiency as that can be obtained from using SOC.

Product literatures of bacterial E.coli culture medium SOC

Technical sheet | MSDS

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Bacterial E.coli culture medium 2x YT broth
1.6% peptone, 1% yeast extract, and 0.5% NaCl

2x YT broth is named in comparing its nutrition content to that of LB broth. It does have 2x as much yeast extract compared to LB broth, but it only has 60% (not exactly 2x) more peptone. Basically 2x YT is a richer medium than LB and can support higher cell density and a longer growth period for E.coli. 2x YT is originally formulated for the growth and maintenance of E.coli and its fibrous bacteriophage such as the M13 phage allows relatively large quantity phage production without exhausting the host.

Product literatures of bacterial E.coli culture medium 2xYT broth or medium

Technical sheet | MSDS

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Bacterial E.coli culture medium TB or Terrific Broth
1.2% peptone, 2.4% yeast extract, 72 mM K2HPO4, 17 mM KH2PO4, and 0.4% glycerol

TB or Terrific broth is a phosphate buffered rich medium. In addition to 20% more peptone and 380% more yeast extract than LB broth, TB also has an added 0.4% glycerol as an extra carbon source. All these nutrients in TB can support E.coli growth to OD600 5 to 8 under normal shaking incubation conditions. TB is commonly used for protein expression and plasmid production in a laboratory scale.

Product literatures of bacterial E.coli culture medium TB or Terrific Broth

Technical sheet | MSDS

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Bacterial E.coli culture medium SB or Super Broth
3.2% peptone, 2% yeast extract, and 0.5% NaCl

SB or Super Broth has 220% more peptone and 300% more yeast extract than LB. Therefore SB is supper rich in peptone and yeast extract. We estimated that the major nutrients in peptone and yeast extract are still in excess well after cells reach saturation while trace nutrients are depleted in the same culture. SB is used for plasmid or protein production.

Product literatures of bacterial E.coli growth medium SB or Super Broth

Technical sheet | MSDS

FAQs of commonly used bacterial E.coli growth media

1. How do you  select a commonly used growth medium for a research project?
2. Why is LB broth the most used medium in many academic labs?
3. What is the difference between LB Miller and LB Lennox broths?
4. Will magnesium (Mg2+) increase the cell densities for commonly used bacterial E.coli growth media?
5. Will agitation increase the cell density for commonly used bacterial E.coli growth media?
6. What is the best commonly used E.coli growth medium for plasmid production?
7. What is the best commonly used E.coli growth medium for protein production?
8. What is the best commonly used E.coli growth medium for phage production?
9. What is the best commonly used E.coli growth medium for making competent cells?
10. What is the highest cell density that may be obtained from commonly used bacterial E.coli growth media?

Price list of commonly used bacterial E.coli culture media in microbiology or molecular biology

Warranty of common bacterial culture media

We guarantee the composition and sterilization of our common culture media. If our products fail to meet such specifications, Exptec will promptly replace the product. In addition, we also guarantee the prices of most our common media. Please email us at info@exptec.com for more information.

Related products of commonly used culture media

High density growth media
DNA ladders or DNA markers
Expression vectors
Competent cells for cloning and expression
E.coli cell strains for protein expression

Related literatures of commonly used culture media

Bacterial growth media
Plasmid DNA yield
Protein yield
Protein solubility
Toxic protein cloning and expression

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