The mycological lesson: Agar Plates (MYA)

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In this mycology lab lesson, our mycologist, Alexia Kumer, demonstrates how to produce growth media for growing mushrooms using agar plates. Using simple techniques at home, you will be able to make “Petri dishes” for your favorite edible and medicinal mushrooms. And although we worked in sterile premises to create this lesson, these same techniques can be adapted to a home setting using a clean workspace like in our SAB, which we sell on our site.

“In the highly competitive natural world, the chances of mushroom spores germinating and then producing a mushroom are slim. Within a laboratory, isolated from atmospheric contamination, the probability of success is much greater. What a grower does is remove a selected species from the fierce competition of the outdoors and place it in an optimized environment indoors where the mushroom mycelium grows unhindered by the ravages of nature. This haven of quiet refuge is, in effect, the sterile laboratory.”

–Paul Stamets, “A Simplified Overview of Mushroom Cultivation Strategies”

Note: If you do not wish to produce your own medium, you can purchase premixed agar plates and slants by clicking the links below.

https://lejardinmycelia.com/products/boites-de-petri-60mm-avec-agar-agar-mya

The plates are the working surface for working with mushrooms. They allow you to observe growth patterns, colonization rates and give you the opportunity to separate different strains of mycelium isolated from the spores of a single fungus. The plates are useful for cloning wild mushroom strains, isolating specimens from contaminants and conducting cross-breeding assays between different mushroom strains. The plates contain a solid growing medium composed of natural sugars and agar, a gelatinous substance derived from red algae that gives the mycelium an anchor while we do our work.

For the plates, we will use MYA culture medium, short for “malt, yeast, agar”. In MYA, malt extract provides sugars and carbohydrates while yeast provides additional nutrients. Once the solution is prepared, we will pasteurize it in a pressure cooker to ensure that all rival microbes are eliminated.

Step 1: Ingredients needed:

• Plates: 500 ml of water, 10 grams of malt, 10 grams of agar, 1 gram of yeast.

Important: Seal your container but do not overtighten. This allows any pressure or condensation to escape. Heat until boiling.

Step 2: While the water is heating, measure your dry ingredients and add them to the appropriate bottle, jar, or flask following the recipes above. Wait for the mixture to combine completely and heat to desired temperature.

Step 3: Once your solution is ready, prepare the pressure cooker. You can use any pressure cooker you have at home for this step, but be sure to follow the instructions for the particular model. Next, take your solution, make sure it is lightly covered, and place it inside. Close the pressure cooker properly, making sure each screw is balanced.

Step 4: Set a timer for 30 minutes. Pressure cookers vary, so be sure to follow the instructions to ensure your plates are properly sterilized.

Step 5: This process requires a laminar flow hood or SAB (glove box). Sterilize your space, including your laminar flow hood, gloves and plates. Remove your MYA plates from the pressure cooker (make sure the pressure has dropped), and place them inside the laminar flow hood or SAB. Be careful as your environment may be hot.