DNB

Difco Nutrient Broth (DNB)

Difco Nutrient Broth is a rich medium commercially available from BD and routinely used for cultivating many non-fastidious organisms. It contains beef extract and peptones; exact composition will vary between batches.

Preparation

Per Litre:

• 4g Difco Nutrient Broth Powder
• 1L dH₂O

Instructions

1. Add DNB powder to dH₂O and mix to dissolve
2. Autoclave

Uses

• Selection for resistance to salt-sensitive antibiotics
• Streptomyces Bacteriophage plaque assay
• High titre preparation of phage
• Isolation of phages from single plaques
• Isolation of phages from environmental samples

Notes

According to the recipe in Practical Streptomyces Genetics, it should be 8g of DNB per litre, however some groups choose to use 4g instead. This has little effect on the ability of Streptomyces to grow on the soild medium, DNA.