Recipe for FM Medium

Recipe for FM Defined Medium

Contributed by Jakob Franke August 7, 1992 and updated in September 1999. Published in Franke and Kessin 1977.

Notes from Jakob Franke:

  • FM Defined Medium can be made up from 4 stock solutions (amino acids, vitamins, salts, and trace metals) which can be stored indefinitely at -20°C . The composition of the stock solutions is given below.
  • Glucose, phosphate, and dihydrostreptomycin-sulfate are added as solids.
  • The medium can be autoclaved or filter sterilized and is stored in the dark at 4°C.
  • Gibco-BRL has made a batch of the medium, and so has Sigma (cat. no. F-8787), but both batches are sold out as far as I know.
    The medium is still available from BIO101 (cat. no. 4115-025 for 1 pack to make 1 L; cat. no. 4115-075 for 10 packs, and 4115-095 for 100 packs).
  • It seems that some people experience the formation of a precipitate in the medium upon standing. We have never seen this with either home-made medium or the Sigma medium.  Anyway, do NOT remove the precipitate, since the medium will not support growth if the precipitate is removed.

[INDEX]


FM media (1 liter) (see stock solutions below):

  • 250 ml 4x amino acids
  • 50 ml 20x vitamins
  • 20 ml 50x salts
  • 0.1 ml 10,000X trace metals
  • 10 g glucose
  • 0.87 g K2HPO4
  • 50 mg dihydrostreptomycin-sulfate


Check the pH and adjust to 6.5 if necessary (HCl or NaOH).
Adjust the volume to 1 liter with distilled (or deionized) water and autoclave.
We often adjust the volume to 90% of the final volume to leave room for supplements.

[INDEX]


Stock Solutions:

  • 4x amino acid stock (in 8 mM NaOH) (5 liters)
    • 1.6 g NaOH
    • 14 g arginine·HCl
    • 6 g asparigine
    • 4 g cysteine
    • 10 g glutamic acid
    • 18 g glycine
    • 6 g histidine·HCl-H2O
    • 12 g isoleucine
    • 18 g leucine
    • 18 g lysine·HCl
    • 6 g methionine
    • 10 g phenylalanine
    • 16 g proline
    • 10 g threonine
    • 4 g tryptophan
    • 14 g valine

    The pH should be about 4.2.
    Adjust the volume to 5 liters and store at -20°C (we freeze 1/2 liter aliquots).
    Stick to the amino acid forms indicated, otherwise solubility problems will arise.

  • 50x salts (1 liter)
    • 50 ml 1 M NH4Cl
    • 1 ml 1 M CaCl2
    • 50 ml 0.1 M FeCl3
    • 20 ml 1 M MgCl2

    Adjust volume to 1 liter and store at -20°C.

  • 20x vitamins (1 liter)
    • 100 ml biotin (4 mg in 1 liter 10 mM NaHCO3)
    • 20 ml cyanocobalamin (5 mg in 1 liter H2O)
    • 100 ml folic acid (40 mg in 1 liter 10 mM NaHCO3)
    • 100 ml lipoic acid (80 mg in 1 liter 10 mM NaHCO3)
    • 100 ml riboflavin (100 mg in 1 liter 10 mM NaHCO3)
    • 100 ml thiamine·HCl (120 mg in 1 liter H2O)

    Adjust volume to 1 liter and store at -20°C.

  • 10,000x trace metals (100 ml)
    • 4.84 g Na2-EDTA·2H2O
    • 2.30 g ZnSO4.7H2O
    • 1.11 g H3BO3
    • 0.51 g MnCl2·4H2O
    • 0.17 g CoCl2·6H2O
    • 0.15 g CuSO4·5H2O
    • 0.10 g (NH4)6Mo7O24·4H2O

    Adjust pH to 6.5 and volume to 100 ml. Freeze aliquots at -20°C.

[INDEX]

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