How are oyster mushroom cultures cultivated? Three measures to grow high-quality cultures

Cultures are divided into mother cultures, stock cultures and spawn cultures. They are also commonly called first-level, second-level and third-level cultures, and their cultivation methods differ. The key technical points are described below:

1. Mother culture cultivation: This refers to the culture obtained by tissue isolation or spore isolation. The mother culture medium is usually prepared with potato agar medium. To prepare 1000 ml of medium, use 200 g of potato, 18-20 g of agar, and 20 g of glucose.

Method: First wash and peel the potatoes, cut them into small pieces the size of broad bean grains, boil them in 1000 ml of water for 30 minutes, filter through 6-8 layers of gauze, and make up the lost water. Add the agar and let it dissolve, then add the dissolved sugar, and add water to bring the volume to 1000 ml. Then dispense into test tubes, filling each tube 1/5-1/4 full, and add a cotton plug and wrap with paper. Sterilize at 1.2 kg pressure for 30 minutes, and while hot, slant them. After cooling, place them at 25°C-27°C and observe; if there is no contamination, they can be inoculated. One mother culture can be transferred to 25-30 tubes.

The tubes inoculated under sterile operation are placed under constant temperature at about 25°C for cultivation, and after about half a month the mycelium can cover the tube. During cultivation, care should be taken to remove tubes contaminated by stray microorganisms. The well-cultivated mother cultures are moved into a refrigerator and stored at 4°C for half a year, or stored at room temperature for three months.

2. Stock culture cultivation: The raw materials can be sawdust or cottonseed hulls. Sawdust medium formula: sawdust 78%, wheat bran or rice bran 20%, sugar 1%, gypsum 1%. Cottonseed hull medium formula: use 50 kg of cottonseed hulls plus 3% potato extract liquid, (the filtrate from 1.5 kg of potatoes cut into paste and boiled for 30 minutes), sugar 0.1%, magnesium sulfate 0.1%.

Method: Add water to the culture material and mix evenly. The moisture level is suitable when the material is squeezed tightly in the hand and water droplets are visible between the fingers but do not drip down; generally the material-to-water ratio is 1:1.2-1.3. Then fill bottles. The bottling method is to shake the bottle gently while filling so that the upper and lower parts of the bottle are suitably compact. Fill up to the shoulder of the bottle and press the material flat, wash the culture material off the inside and outside of the bottle mouth, add a cotton plug, wrap with paper and tie it, then place it in a high-pressure sterilizer for sterilization at 1.5 kg pressure for one hour. After cooling, inoculate under sterile operating conditions. Introduce the mother culture from the test tube into the bottle; one mother culture can inoculate 4-5 bottles of stock culture. After inoculation, place at 25°C constant temperature for cultivation for about one month, and when the mycelium covers the bottle, it is stock culture.

3. Spawn culture cultivation: The preparation of spawn culture is actually an expanded cultivation of the stock culture. The formula of the sawdust medium for spawn culture is the same as the formula for stock culture cultivation. The formula of the cottonseed hull medium is also the same as the formula for stock culture cultivation. After bottling, sterilize, and under sterile conditions, inoculate the stock culture into the spawn culture bottles. One bottle of 750 ml stock culture can inoculate 80-100 bottles of spawn culture. After inoculation, place at 25°C constant temperature for cultivation for about one month, and after it fully covers the bottle, it can be used for sowing. When cultivating stock cultures and spawn cultures, check once every 2-3 days after inoculation, until the mycelium covers the surface of the material, then check once a week. Pick out cultures contaminated by stray microorganisms and dispose of them far away from the cultivation room.