AGAR AGAR TEK 101

[myco_jordan]

Agar, derived from certain species of red algae, is a gelatinous substance widely utilized in mycology and even cooking. Known for its solidification properties, transparency, and nutrient base, agar serves as a stable medium for culturing fungi. Its versatility and ease of use make it an indispensable tool in mycological practices, facilitating the observation, study, and experimentation of mycelium. In essence, agar provides a 2d plane for the mycelium to grow across, making it easier to observe and manipulate using advanced techniques. Providing the literal foundation for scientific exploration in the field of mycology.

Agar pouring technique and recipes are cornerstones in mycology, an essential tool for fungal cultivation and research. This post dives into agar pouring, focusing on its applications in mycology and comparing pre-pour and post-pour techniques. We will explore agar recipe formulations, sterilization protocols, and pouring methods, shedding light on considerations essential for successful fungal growth and experimentation. Let us navigate agar pouring intricacies, uncovering the secrets to advancing our mycological exploration.

We will start with some common agar recipes which can be used for either technique, including some optional supplements. These recipes are for 500ml media flasks however they can be scaled accordingly to your needs.

500 ml distilled water
15-20 grams agar agar powder
10-15 grams light malt extract

500 ml distilled water
15 grams agar agar powder
10 grams soy peptone

500 ml distilled water
15 grams agar agar powder
10 grams yeast extract

As you can see there are several supplements you can use to provide nutrient to the agar plate, allowing you to fine-tune and experiment with the growing parameters. But they all require a base of water and agar powder. You can even mix and match the supplements and there are many more suitable materials you can add to the recipe to supplement it. Agar itself is nutritious for mycelium, you could skip the supplement and technically just use agar and water, although your results may not be as robust if you had used a nutrient supplement in the recipe. All up to you!

Pre-Pour Agar Plate Technique:

This method involves preparing the agar solution and pouring it into sterile autoclavable petri dishes in advance to sterilization of the agar media.

Materials Needed:

Agar powder, optional supplements
Distilled water
Autoclavable petri dishes (pp5, 4oz glass jam jars, glass petri)
Autoclave or pressure cooker
Sterile gloves
Sterile environment (e.g., laminar flow hood, SAB)

Step-by-Step Process:

Prepare Agar Solution:

Measure the appropriate amount of agar powder according to your recipe.
Dissolve the agar powder in distilled water in a flask or beaker.
Stir the solution thoroughly to ensure the agar is completely dissolved.

Pouring Agar Plates:

Open each petri dish and pour a sufficient amount of agar solution to cover the bottom. You do not need to work in SAB or Laminar flow for this step.
Replace the lid of each petri dish and stack into your pressure cooker.

Autoclave or Sterilize:

Pressure cook the agar plates at 15 psi for 30 minutes to sterilize them.

Allow Agar to Solidify:

Allow the agar plates to cool and solidify at room temperature for several hours or overnight.
Once solidified and cooled, they are ready to use, or be stored in a cool dry, clean place.

Pour Agar Plate Technique:

This method involves sterilizing the agar solution, letting it cool but not solidify and then pouring it directly into sterile petri dishes. With this method the petri’s do not undergo an autoclave or pressure cycle, only the agar media does. Allowing for use of pre sterile inexpensive plastic petri dishes, or reusable glass dishes that have been sterilized.

Materials Needed:

Agar powder, optional supplements
Distilled water
Sterile petri dishes
Autoclave or pressure cooker
Sterile gloves
Sterile environment (e.g., laminar flow hood, SAB)

Step-by-Step Process:

Prepare Agar Solution:

Measure the appropriate amount of agar powder according to your recipe.
Dissolve the agar powder in distilled water in a flask or beaker.
Stir the solution thoroughly to ensure the agar is completely dissolved.
Autoclave or Sterilize:

Pour the agar solution into autoclavable media bottle.
Cap the bottles loosely to allow steam to escape during sterilization. Recommend covering with foil to excess moisture to enter the bottle during pressure cycle and cooling.
Pressure cook the agar solution at 15psi for 30 minutes to sterilize it.

Cool Agar Solution:

Allow the sterilized agar solution to cool until it reaches a temperature of around 50-55°C (122-131°F).
At this temperature, the agar solution is still liquid but not too hot to handle, or damage petri dishes.

Prepare Petri Dishes:

Open each sterile petri dish and place them in a sterile working area.
Arrange the petri dishes in a stack to easily pour into each dish in succession.

Pouring Agar Plates:

Wear sterile gloves and work quickly but carefully to minimize contamination.
Pour a sufficient amount of agar solution into each petri dish to cover the bottom.
Replace the lid of each petri dish immediately after pouring to prevent contamination.

Allow Agar to Solidify:

Allow the agar plates to cool and solidify at room temperature for several hours or overnight.
Once solidified, store the agar plates in a cool, dry place until ready for use.

By following these step-by-step processes, you can effectively prepare agar plates using both pre-pour and pour techniques for your mycology experiments. Why you would choose one over another is purely preference. Either method can be scaled to make your situation easier or more timely. If I had to make as many plates as possible in as little time as possible I would likely utilize post-pour technique and in front of a flow hood. Otherwise pre-pour works flawlessly for more nimble projects, I personally work in front of a flow hood but prefer pre-pour if I’m restricted to SAB use. Careful planning will make the objective best technique for your use-case clear, good luck friends!

[Author]

Posts