condition of culture

1. Nutrition

carbon source

How to use Cordyceps militaris

Carbon source is the basis for Cordyceps militaris to synthesize carbohydrates and amino acids, and it is also an important energy source. In artificial culture, Cordyceps militaris can use glucose, sucrose, maltose, starch, pectin and so on. Among them, small molecules such as glucose and sucrose have the best utilization effect.

Nitrogen source Nitrogen element is organic nitrogen such as protein and nucleic acid synthesized by Cordyceps militaris and inorganic nitrogen such as ammonium salt. There are many available organic nitrogen, such as amino acids, peptone, bean cake powder, silkworm chrysalis powder and so on. Inorganic nitrogen mainly includes ammonium chloride, sodium nitrate and diammonium hydrogen phosphate. Organic nitrogen has the best utilization effect.

The main mineral elements are phosphorus, potassium, calcium and magnesium. Inorganic salts are generally added to meet the demand of Cordyceps militaris for mineral elements.

Vitamin Cordyceps mycelium can't synthesize essential vitamins, and proper addition of VB 1 is beneficial to the growth and development of mycelium.

2. The temperature has the boundaries of optimum temperature, minimum temperature and maximum temperature in different growth and development stages of Cordyceps sinensis. The growth temperature of mycelium is 6℃-30℃, below which it rarely grows, and above 30℃ it stops growing or even dies. The optimum growth temperature is 65438 08℃-22℃; The growth temperature of fruiting body is 10℃-25℃, and the optimum production temperature is 20℃-23℃. The differentiation of primordium needs a large temperature difference stimulation, and the temperature difference should generally be maintained at 5℃- 10℃.

3. Moisture and humidity Moisture is an important part of Cordyceps militaris cells. In the mycelium growth stage, the water content of the culture medium is kept at 60%-65%, and the relative humidity of the air is kept at 60%-70%. In the growth stage of fruiting body, the water content of culture medium should reach 65%-70%, and the relative humidity of air should be maintained at 80%-90%. Pay attention to replenish water and nutrient solution in the culture medium in time.

4. Air Cordyceps militaris needs a small amount of air. However, proper ventilation is needed to increase fresh air during the fruiting body occurrence period. Otherwise, too much carbon dioxide will accumulate, and the daughter will not differentiate normally, which will affect the growth and development.

5. Illumination spore germination and mycelium growth stage do not need light, and should be kept in a dark environment. However, the transformation to reproductive growth stage requires bright scattered light, and the illumination is 100-240 Le (Le is the unit of illumination). Strong light, dark hyphae, good quality and high yield.

6. The pH value of Cordyceps militaris is acidic fungi, and the optimum pH for the growth and development of its mycelium is 5.2-6.8. However, during sterilization and culture, the pH value will decrease. Therefore, when preparing the culture medium, the pH value should be raised to 1- 1.5, and 0. 1%-0.2% potassium dihydrogen phosphate or dipotassium hydrogen phosphate can be added when preparing the culture medium. After long-term asexual propagation and repeated test-tube transfer, the female parent gene of Cordyceps militaris is prone to mutation, abnormal grass, and decreased yield and quality. Therefore, in production, Cordyceps militaris strains should be sexually propagated at regular intervals. Specifically, high-yield, high-quality and early-maturing Cordyceps militaris fruiting bodies are selected, after surface disinfection with 0. 1% mercuric chloride solution or 75% alcohol, the surface liquid medicine is washed with sterile water, suspended above a container filled with a comprehensive culture medium, and allowed to stand for culture at 2 1℃-23℃. When a colony of Cordyceps stellatus appears on the surface of the culture medium, a single sample is selected from the inoculation box. The mycelium of Cordyceps militaris was covered with inclined plane and purified. The obtained spore mother seed must be compared with the weeding test, and the high-quality cordyceps fruiting body should be selected again for tissue separation, and then it can be used to expand the cultivated varieties after screening.

After expanded culture, the mother seed was placed on rice culture medium and cultured at 18℃-20℃ for 20-30 days, and the growth was observed. If bacteria or mold pollution is found, the mother seed should be further purified; If there is no mixed bacteria pollution, the culture can be continued, and orange-red fruiting bodies will be produced after one month, which shows that the mother seed is reliable. Secondary seed culture: The liquid culture medium was subpackaged in 500ml triangular bottles, each bottle contained 200ml culture medium, and sealed with 12 gauze and one layer of kraft paper. After the mother seed is sterilized by 13-30 minutes, it is inoculated into triangular bottles with inoculation hooks under aseptic conditions, and each inclined plane can be inoculated with more than 10 bottles. After inoculation, it can be cultured in a shaker at 20℃ for about 5 days, and then it can be used as a cultivated seed after forming uniform pellets.

It is worth noting that if the culture solution becomes mixed, there are two possibilities: one is to eliminate bacterial pollution; Second, it is caused by the thick growth of mycelium. If it is difficult to judge, a microscopic examination can be performed. Using rice and corn as main raw materials to prepare culture medium, adding 10%-25% silkworm pupa powder or milk powder to improve the quality of Cordyceps militaris fruiting body. The culture medium and nutrient solution are mixed according to the ratio of 1: 1, and the pH value is controlled at 5.5-7.0. Bottle, sterilize and inoculate as usual.

Mycelium culture

After inoculation, the bottle should be cultivated in a clean and dark environment, and the air humidity should be protected at 60%. At the beginning, in order to reduce the pollution of miscellaneous bacteria, the indoor greenhouse should be kept at 15℃- 18℃. When the surface of the feed is covered with Cordyceps mycelium, the temperature is raised to 20℃-23℃ about 15d, and the mycelium can completely ingest the culture and complete the vegetative growth.