Jiangsu xinyi city Kangyuan Edible Fungi Institute Tel:05 16-88939450
Cordyceps militaris, also known as Cordyceps militaris, belongs to the order Ergotaceae of Ascomycetes. In recent years, wild resources are increasingly scarce, and artificially cultivated Cordyceps militaris is well received by consumers for its good medical and health care effects.
1. Biological characteristics of Cordyceps militaris
1, nutrition: The main carbon source substances available to Cordyceps militaris are glucose, sucrose, maltose, starch, pectin, etc., but the utilization effect of monosaccharide or small molecule disaccharide is better. Secondly, nitrogen is an essential element for Cordyceps militaris to synthesize protein and nucleic acid substances, and there are many kinds of nitrogen substances that Cordyceps militaris can use, especially organic nitrogen, such as peptone, bean cake powder, yeast extract, etc. Some inorganic nitrogen can also be used, but the utilization effect of organic nitrogen is better. Thirdly, the essential element in the growth of Cordyceps militaris hypha and its stroma is mineral element, so it should be added appropriately in production. Fourthly, proper amount of auxin can effectively stimulate and promote the growth of Cordyceps militaris mycelium, and greatly improve its biomass. Adding vitamins is the main measure in production. Finally, a reasonable substrate C/N ratio (CN) is a necessary condition for artificial cultivation of Cordyceps militaris. Otherwise, it will lead to slow growth of hyphae, serious pollution, or overgrowth of aerial hyphae, which makes it difficult to generate daughter seats. Even if there is daughter seat differentiation, the quantity and quality of its products will be reduced to varying degrees. In production, it is generally appropriate to adjust CN between 3-4:1.
2. Temperature: the growth temperature of Cordyceps militaris mycelium is 6-30 C, and the optimum temperature is18-22 C; The differentiation temperature of primordium is between10-25 C. In order to stimulate the timely formation of primordium in production, the temperature difference can be appropriately controlled within the range of 5-10 C within 24 hours. The submount growth temperature is10-25 C, and the optimum is 20-23 C; Spore ejection temperature is 28-32 C, and the highest temperature should be controlled below 34°C; If it is not for breeding or separation and special needs, it should not reach or exceed 28°C when it is simply cultivated for the purpose of obtaining fruiting bodies.
3. Moisture: Moisture is an important foundation of life, and Cordyceps militaris is no exception; As an essential solvent for mycelium and stroma, most of the water needed by Cordyceps militaris comes from the culture medium. Therefore, it is directly related to the growth and development of Cordyceps militaris to adjust the moisture content of the substrate to an appropriate level. In actual production, the moisture content of the substrate should be adjusted to 60%-65%, the relative air humidity should be kept at 60%-70% in the mycelium culture stage, and it should be adjusted to 80%-90% after the primordium is formed.
4. Oxygen: Cordyceps militaris is similar to other edible fungi, and its growth and development process is also a metabolic process of absorbing oxygen and discharging carbon, especially after the primordia are differentiated, the oxygen demand is more, so it is necessary to maintain relatively fresh air to ensure sufficient supply of oxygen. However, due to the slow growth rate, small metabolism and relatively high carbon dioxide tolerance of Cordyceps militaris, the concentration of carbon dioxide in production can be satisfied at about 0.5%.
5. Illumination: In the prophase of the growth of Cordyceps militaris, that is, the mycelium development stage, light, especially strong light, has a great inhibitory and damaging effect on the mycelium, so it should be kept completely dark. Even if light treatment is carried out in advance when the fungus is completed, it will induce people to enter the reproductive stage prematurely, which will seriously reduce the yield and greatly reduce the quality. After all the bacteria are full, it takes about 200 lux of light to stimulate the color change. If the light is uniform and the time per day reaches 10 hour, the hyphae can turn good and have a deep color, which lays the foundation for obtaining high-quality fruiting bodies in the later stage. This characteristic is consistent with the situation that wild Cordyceps militaris does not have a seed seat under dense shade. After the primordium appears, the illumination time can be shortened appropriately, the illumination intensity can be increased to 300 lux, and the illumination should be uniform, so that the fruiting body can develop and grow normally.
6. pH value: Cordyceps militaris is suitable for acidic environment, and the mycelium growth stage is suitable for 5-7 substrates, and the optimum is 5.2-6.8. During artificial cultivation and production, the pH value of the substrate can be adjusted to 7-7.5, and after autoclaving, the pH value naturally decreases, and with the natural adjustment of the mycelium (producing organic acids) in the later stage, the pH value of the substrate can be reduced to about 6.
Second, the production of strains
1, obtaining the provenance with strong adaptability and high yield is one of the key conditions for the successful cultivation of Cordyceps militaris. Except for conditional self-separation and cultivation, most producers need to obtain it through introduction channels.
2. Formulation of strain transfer tube: glucose10g, peptone10g, yeast extract 2g, potassium dihydrogen phosphate1.5g, magnesium sulfate 0.6g, VB 1 50mg, agar15-20g. Routine sterilization and other operations, using the prepared provenance inoculation, generally each provenance can be transferred to about 20. Cultured at 23-25 C, after about 10 days, the mycelium grows full of inclined planes, which is the first-class mother seed; The secondary mother seed can only be used for cultivation and production, and it is not allowed to be further expanded, otherwise, it will lead to the serious consequences of "grass production" being rare and sparse, or even "grass production" at all.
3. Liquid spawn production has many advantages, such as large one-time production, short production cycle, easy manual control, rapid spawning after cultivation and inoculation, and three-dimensional occupation of material surface by mycelium, etc. Now it has become the first choice for Cordyceps militaris cultivation.
4. Selection of strains: The key to successful and efficient cultivation is to choose fast-growing high-yield and high-quality strains with white hyphae, strong adaptability, color change after seeing light, fast grass emergence and stable characters.
Third, the raw material requirements
1, choose fresh mouldy and pollution-free rice.
2. Canned bottles or high-quality polypropylene plastic bags with a thickness of more than 0.05mm, specifications of15cm× 30cm or17cm× 30cm, uniform thickness, no leakage and strong toughness are used as cultivation containers.
Fourth, cultivation management
1, medium formula: rice or wheat 1 kg, water 1.5 kg. (Formula of nutrient solution: silkworm pupa powder 100g, sucrose 50g, peptone 10g, VB 1 50mg)
2. Preparation method: 50 grams of rice or wheat per bag or 100 grams are put into bottles or plastic bags. According to the ratio of rice or wheat to nutrient solution 1 g: 1.5 ml, weigh the nutrient solution and pour it into a bottle or plastic bag filled with rice. After subpackaging, tie the middle part and the mouth of each plastic bag with a plastic rope; .
3. Sterilization: add a proper amount of water into the sterilization pot, put the culture bag into the sterilization pot, raise the temperature to 100℃ and keep it for 8 hours. Take it out, cool it and move it into the inoculation room (box). After sealed disinfection with high-quality aerosol disinfectant or conventional methods, it can be inoculated.
4. Inoculation: Close the door quickly when entering the inoculation room (to prevent air containing miscellaneous bacteria from entering). Inoculation tools, outer walls of strains and hands of operators shall be wiped with 75% alcohol. This paper introduces an easy-to-popularize inoculation method with solid rice strains:
(1) Transfer and expansion cultivation of original seed in test tube: after the test tube plug is removed, 2-3 pieces of bean-grain-sized strains are dug with sterilized inoculation hooks, inoculated on the culture medium surface, and the bag mouth is slightly tightened.
(2) When the original seeds are used to expand the cultivation bags, the strains are first pounded into blocks the size of fingers or beans, and 5 5- 10/0g strains are inoculated into each bag and evenly distributed on the material surface. If conditions permit, the inoculation amount can be appropriately increased to facilitate the rapid growth of hyphae. After inoculation, the bag mouth is slightly fastened according to the original method of tying the mouth, and then it can be moved into a sterilization and insect-proof culture room for culture.
(3) In the case of liquid seed inoculation, under aseptic conditions, open the sealing material and spray the liquid seed evenly with an inoculation gun. The inoculation amount depends on the size of the container, and some liquid strains are inoculated by adding a certain proportion of sterile water.
5. Management: Cordyceps militaris is a medium-low temperature fungus, with the mycelium growth temperature ranging from 5-30℃, the optimum growth temperature of mycelium being 15-25℃, and the optimum growth temperature of stroma being 18-22℃. Generally, the temperature is initially kept at 15- 18℃ for shading culture. When the mycelium grows to the medium 1/2-2/3, the temperature can be raised to 20℃, and the mycelium can be full of bags in 20 days (liquid strain 1 week or so). A few days later, when hyphae appeared in the upper part of the culture medium, the temperature difference of 10- 15℃ was given, and the light was increased to stimulate the color change. 7- 10 day after the color change, disinfect the culture room for 30 minutes, then untie the rope in the middle of the culture bag, and fold the bag into a straight tube by hand to provide space for the growth of the sub-seat. When the sub-seat reaches 1 cm, ventilate the cultivation bag in time; Bottles or plastic pots can be cultivated by punching holes in the sealing film for ventilation. The temperature is maintained at 18-22℃ and the air relative humidity is 80-90%.
6. Harvesting: When the submount is orange or orange rod-shaped and no longer grows, open the bag mouth and pick it from the base with a knife or scissors, and put it into a clean appliance to dry or dry it in time, so as not to be exposed to the sun to avoid fading. Store in a closed plastic bag after drying.