Liquid Culture

Agar recipes

Potato Dextrose (Yeast) Agar - PDA, PDYA and PDYPA

    • 1000 milliliters (1 liter) water
    • 300 grams of potatoes (i. e. the broth from boiling potatoes in 2-3 liters of water for 1 hour)
    • 10 grams dextrose (or glucose)
    • 20 grams agar agar
    • 2 grams yeast (optional)
    • 1 gram peptone (optional)
  • This medium is designated PDA, or PDYA and PDYPA if yeast and peptone are added. Note that only the broth from boiling the potatoes is used-the potatoes are discarded. The total volume of the final media should equal 1 liter. Dextrose can be substituted by corn syrup or honey.

Malt Extract (Yeast) Agar - MEA, MYA and MYPA

    • 1000 milliliters (1 liter) water
    • 20 grams malt sugar (or maltose)
    • 20 grams agar agar
    • 2 gram yeast (optional)
    • 1 gram peptone (optional)
  • The above medium is abbreviated as MEA, and MYA or MEAY with yeast and MYPA with peptone. It is unclear whether malt sugar need to come from barley, or any other cereal. Malt sugar may contain wheat starch and

Ingredients

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Main
    • Agar or Agar agar : nutritious gelatinous substance. Powder is used and can be found in asiatic supermarkets.
    • Yeast :several yeast can be used. Is not critical for most of the species.
      • baking dry yeast to bake patry, that can be found in bakery, used to make bread. 7g of dried yeast equivalent to 25g fresh for 500g flour (e.g. from MRCA Shop).
      • nutritional yiest to eat, from health stores.
      • brewery yeast to make bear, can be found at breweries (as well as malt syrop).
    • Peptone: is often soybean derived. Is not critical for most of the species.
Additional
    • Antibiotics : Toxic to bacteria but not to fungi. Gentamycin or Streptomycin are thermo resistant to autoclaving. Other antibiotics (e.g. penicyllin) must be added at agar cooling, between 40 and 60 degree. [todo: find dosage] (or a liquid spray of 30 mg/l Streptomycin, or 2mg/l. Chlortetracycline)
    • Peroxid : Used to prepare agar for cloning. Toxic to all fungi but not to bacteria, used against mold but also harm mycelium. Experimented growers strongly advise to avoid it for this reason (see shroomery post). [todo: find dosage, thermo resistance]
    • Active Charcoal : "recommended for any mushroom whose spores do not easily germinate" [1]. Provoke pinning in casing species.
    • Salt, Chalk : PH adjustment
    • Gypsum : PH buffering
    • Cinnamon : against molds, action medium antibiotics (antibacterial) and possibly anti-fungal against cobweb and trichoderma (ph?)
    • Zeolite : Provoke pinning in casing species.

Notes about agar

  • Some of the final fruiting substrate (e.g. wood, straw) is sometimes added in the agar, to get the mycelium used to it early in the process. Using a different medium from time to time will prevent the culture getting used to one medium. 500 ml of medium will pour around 20 petri dishes. All media have a near-neutral pH and should be sterilized for twenty to thirty minutes at 15 psi pressure. When cold, be sure your medium into the petri isn't full of water drops.
  • "A Petri dish pour requires about 12 ml and a slant needs 6 ml"[4]. 40 ml per dish, "1/2 of a liter will make about 12 dishes of agar"[5]

References

  1. Growing Gourmet and Medicinal Mushrooms, Paul Stamets, P106
  2. The mushroom cultivator, by Paul Stamets, P27
  3. Extensive agar recipe list: FastFred's Media Cookbook (v0.97)(8-30-2004), by FastFred
  4. http://www.eng.umd.edu/~nsw/ench485/lab8b.htm
  5. http://www.shroomery.org/8505/Fatguys-Agar-Technique