M9 Minimal Salts media is a commonly used basic and chemically defined bacterial growth media for cultivation of E. coli strains. It provides only the necessary nutrients (carbon, nitrogen, phosphorus, sulfur, and metal sources) required for bacterial growth.

Our Gibco M9 Minimal Salts (2X) is a ready-to-use concentrated base formulation that can be supplemented with various carbon sources and amino acids to make a complete M9 medium. This medium is preferred in microscopy of E. coli experiments as it has a low autofluorescence and absorbance properties. Growth rates decrease at lower or higher osmolarity, and M9 medium has a lower osmolarity (∼0.25 Osm/L) than E. coli needs to optimally grow (∼0.3 Osm/L). This allows for tight control over bacterial growth.

M9 Minimal Salts (2X) formulation
Formulation per liter:
25.6 g Sodium phosphate (dibasic) heptahydrate
6 g Monopotassium phosphate
1 g Sodium chloride
2 g Ammonium chloride

• A carbon source needs to be added to required concentration
• Additional components might be needed for E. coli strains (e.g. thiamine for DH5α, leucine for DH10B)

Primary applications
• Recombinant protein induction in E. coli in extended growth phase (improved protein expression)
• Microscopy or fluorescence measurements experiments using bacteria
• Metabolic activity studies in bacteria with controlled chemical media composition

Gibco media bottles
Each media bottle features an angled opening for simplified pipetting. The 1 L Gibco media bottle uses 39% less source material than comparable media bottles on the market. Both the cap and bottle can be recycled as they are made from highly recyclable high-density polyethylene (HDPE) and polyethylene terephthalate (PETE).

Find the media format that fits your needs
We offer other ready-to-use media formulations, such as LB Broth, Terrific Broth or S.O.C recovery medium.
Explore other media formats for bacterial growth.