What is a Liquid Mycelium Culture, aka liquid culture?
The preservation of mycelium for propagation on grain spawn is a fundamental aspect in cultivation.
Mycelium cultures can be preserved in two main ways, on agar plates or in a liquid culture (aka liquid culture, LC).
Difference? Only one!
The agar plates consist of:
water + agar agar + food
The liquid culture from:
water + food
What are the main advantages and disadvantages of using liquid culture instead of agar plates?
The main advantages are mainly 3
- Possibility of working even in non-sterile environments (through the use of sterile syringes and needles)
- Possibility of using it to inoculate large quantities of sterile cereal
- Possibility of keeping it for a long time (in the fridge)
The disadvantage however is mainly 1
- Difficulty seeing certain types of defilements
How do you prepare a liquid culture?
1. First you need to have a jar and have a cap for liquid cultures.
This cap must have an injection port and a filter for the passage of air. Take a look at these caps to get an idea!
The filter will allow your mycelium to breathe while keeping contamination away. While the injection port will allow you to use sterile needles and syringes for inoculation of LC and to withdraw LC to be used to inoculate sterile cereal.
2. Add water and your chosen nutrient (e.g. malt extract) at a concentration of up to 4% to the jar (e.g. 4g per 100ml of water), replace the cap, and sterilize in a pressure cooker for 15 minutes at 15 psi (1 bar).
If your pressure cooker reaches lower pressures, the time will be longer. Make sure you don't seal the jar completely with the cap, leave it partially screwed on but make sure you seal it immediately as soon as you open the pot at the end of the cycle (without burning yourself!).
Place foil over the cap to protect the filter from water.
TIP :ย It is convenient to insert a magnetic stir bar inside the jar to easily mix your crop during growth. But this is not necessary. You can mix the liquid inside with a twist of the wrist or using a syringe: pulling up liquid and injecting it back into the jar, this will separate the growing mycelium hyphae and encourage development.
How do you inoculate a liquid culture?
Once your LC is sterilized and has reached room temperature, you can inoculate it.
For inoculation we recommend using a liquid culture syringe , both for simplicity and growth rate. It can also be inoculated with mycelium on agar, but if this is not done in a sterile environment there is a risk of contaminating the culture, since the jar will have to be opened to insert the agar. Otherwise inoculation with a spore syringe is also possible. However, this is not recommended as the sterility of spores is not guaranteed and therefore there is a risk of contamination of the culture. But positive results are undoubtedly possible even so.
Once inoculated leave it at room temperature preferably above 20C for a week or two and when you see a mound of mycelium growth you can start mixing it. As soon as you see that most of the liquid is made up of bits of thick mycelium, it will be ready to use.
How do you use a liquid culture?
Take a sterile needle and syringe , scoop up your mycelium and inject it into a bag or jar of sterilized cereal .
Now you know what role liquid culture plays in growing mushrooms and how to prepare it! If you want to skip some of the steps, we have prepared a liquid culture kit that will allow you to have it ready in a jar without the need to sterilize it!
