LB medium is the most widely used bacterial culture medium in molecular biology. It supports the cultivation of Escherichia coli, Pseudomonas putida, Vibrio parahaemolyticus, Bacillus species and other bacteria. Easy to prepare and nutrient-rich, it contains peptides, amino acids, water-soluble vitamins and carbohydrates, and is applicable to experiments including gene cloning, plasmid DNA production and recombinant protein expression.High Density LB is a special LB medium developed with refined tryptone and yeast extract for culturing E. coli. It provides more abundant nitrogen sources, peptides and amino acids than standard LB medium. When culturing cloning strains such as DH5α, it yields approximately 50% more cell mass and plasmid DNA than regular LB. For prokaryotic expression strains like BL21 (DE3), its biomass output is 20%–50% higher than conventional LB.
Product Composition：
| Component | High Density LB Broth (g/L) | High Density LB with Agar (g/L) | Concentration (w/v) | | Tryptone | 10 | 10 | 0.01 | | Yeast Extract | 5 | 5 | 0.005 | | NaCl | 10 | 10 | 0.01 | | Agar Powder | — | 15 | 0.015 |
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Instructions for Use:
High-Density LB Agar (Premixed Powder): Weigh one pouch (20g) and add into 450 mL double-distilled water. Wait until tryptone, NaCl and yeast extract are fully dissolved (agar remains undissolved), then adjust the final volume to 0.5 L. Autoclave at 121°C for 20 minutes. Cool the medium to below 55°C before use, or store the sterilized medium at room temperature.
Precautions:
1. pH value (25°C): 7.0±0.1. When this product is mixed with pH 7.0 deionized water, the pH of the medium will be close to 7.0, so it can be used directly without pH adjustment.
2. LB medium shall be prepared with water first and autoclaved at 121°C for 20 minutes before use.
3. Discontinue use if severe moisture absorption of the powder is observed.
4. High Density LB medium supports faster growth of Escherichia coli, with a growth rate about 20% higher than standard LB medium.
5. For preparation volumes less than 0.5 L, add 2.5g medium powder per 100 mL water. Seal the leftover powder tightly and store it in a dry place.
