Liquid culture is a sterilized sugar solution in which the mushroom mycelium can consume nutrients and grow. The various nutrient can add to water like sugar, honey, Karo, and LME. Depending on the type of nutrient, paddy liquid culture usually take 1-2 weeks to expand throughout the jar. This rich-mycelium solution now can be used to propagate more culture, inoculate into the grain jar, or make the agar plate.
The mason jars with the modified lids are usually used to store the sterilized broth that consists of water and 4% Karo or light match extract - LME.
For the agar, inoculation usually occurs in an open-air environment. Thus the grain or substrate is prone to contamination. On the contrary, when working with liquid culture, the risk of contamination is lower since the mycelium goes from the sterile solution to the sterile syringe or reverse. Then mycelium is injected into the sterilized grain jars or bags. However, it has a disadvantage since the contamination is invisible. In other words, you will not see any sign of contamination from liquid culture until inoculated to grains or substrates.
Prepare the Jar lid
Mycelium requires fresh air exchange for healthy growth. Thus the jar lid needs to drill or punch a 1/4 inch hole and cover with a piece of microspore tape for gas exchange.
- Drill a 1/4 inch hole and cover it with high-temperature silicon. This inoculation port can be used to inject or suck up the mycelium without opening the jar lid to reduce the contamination.
Prepare the liquid culture and sterilize
- Add 350ml of warm distilled water to the pint jar.
- Add 14g of LME to the water and steer well.
- Add a small marble ball or magnetic stir bar.
- Cover the jar lid with a piece of aluminum foil.
- Sterilize for 30 minutes at 15 psi
- Wait a couple of hours until the liquid jar cools down before opening.
Inoculate the culture
Your sterilized broth is now ready for inoculating paddy straw mushroom cultures, either by liquid syringe, fresh tissue, or agar wedge.
1. Use paddy straw mushroom culture syringe
- Purchase paddy straw liquid culture syringe online.
- Shake the syringe to spread out the mycelium.
- Sterilize the needle with the flame, then wipe it out with 70% isopropyl alcohol.
- Clean the injection port with alcohol. Then insert the syringe needle into a self-healing port and inject 1-2 cc liquid culture.
- Place the jar in a dark place at room temperature for 3-4 days.
- Stir or shake daily to break down the mycelium mass and allow more air exchange.
- Within 7-14 days, your liquid culture is ready for grain inoculation or culture expansion.
2. Use paddy straw agar plate
An agar plate or petri dish is a sterilized dish that contains a nutrient medium in which mycelium will grow and expand on the plate surface. Paddy mushroom petri dish can be made from the tissue of a mushroom fruitbody or purchased online. Pure colonized agar can inoculate into a liquid culture jar to expand mycelium quickly. When it comes to agar plates, it's vital to adhere to the aseptic technique to reduce contamination.
- Clean your hands and workspace with 70% alcohol.
- Sterilize the scalpel with the flame. Then wipe out with alcohol.
- Open the pure agar dish in the standstill air environment.
- Use a sterilized scalpel to cut a piece of colonized agar, then quickly place it into the liquid culture jar.
- Place the culture jar in a dark place at room temperature.
- Liquid culture is ready to use within 7-14 days.