Essential Knowledge for Introducing Edible Fungi and Simple Methods for Preserving Mother Cultures

Edible fungus mycelium reproduces quickly and mutates easily, making strain preservation relatively difficult. Here are several strain preservation methods that are highly effective and simple to carry out:

1. Liquid paraffin preservation method: Use chemical-grade liquid paraffin. After high-pressure sterilization, place it in a 40°C constant-temperature incubator for several hours or in a desiccator for several days. Using a sterile pipette or syringe, draw up the liquid paraffin and inject it into the culture tube. The injection volume should be about 1 cm above the tip of the slant. Plug with a cotton plug, seal well with wax, and preserve upright in a low-temperature place. It can be preserved for 5 years.

2. Wheat bran preservation method: Weigh out a certain amount of wheat bran, add water or nutrient solution, and mix well. Put the water and wheat bran into a test tube, sterilize under high pressure, then inoculate with the fungus strain, and culture at a suitable temperature. After the mycelium has developed well, place the test tube in a drying room to dry. After drying, store in a dry place below 20°C. It can be preserved for 3 to 5 years.

3. Physiological saline preservation method: Inoculate the fungus strain into potato culture medium, with 60 ml of culture medium per 250 ml Erlenmeyer flask. Culture with shaking or shake 5 to 10 times daily for 5 to 7 days. Then transfer the formed mycelial pellets into test tubes containing 5 ml of sterile physiological saline, with 4 to 5 mycelial pellets per tube. Plug with a cotton plug, seal the tube opening with wax, and place at low temperature. It can be preserved for 1 year.

4. Wheat grain preservation method: Take high-quality wheat, wash it, then soak it in 20°C water for 5 hours. After briefly air-drying, put it into test tubes. The amount filled should be about 1/4 to 1/3 of the tube length. After sterilization, shake it loose while hot. After cooling, inoculate with mycelium, and culture at a suitable temperature until sparse mycelium appears on most wheat grains, then stop. Store in a dry place below 25°C. It can be preserved for 1 to 2 years.