Comprehensive utilization method of cordyceps sobolifera mycoplasm

Abstract

The invention provides a comprehensive utilization method of cordyceps sobolifera mycoplasm, which comprises the following steps: adding selenium element into a solid culture medium (primary mycoplasm) remained after primary harvesting of cordyceps sobolifera sporocarp as a raw material to produce selenium-enriched cordyceps sobolifera spore powder or sporocarp; and after harvesting selenium-enriched cordyceps sobolifera spore powder or sporocarp, adding a selenium element into a residual solid culture medium (secondary mycoplasm) to produce a fungus organic selenium raw material. The selenium-rich cordyceps sobolifera spore powder, the selenium-rich cordyceps sobolifera sporocarp and the fungus organic selenium raw material obtained by adopting the method disclosed by the invention are rich in selenium element, the content of harmful heavy metals is remarkably reduced, and the utilization value of cordyceps sobolifera mycoplasm is greatly improved.

Description

Technical Field

[0001] This invention relates to a method for the comprehensive utilization of solid culture medium (i.e., cicada flower mycelium) during the artificial cultivation of cicada flower, belonging to the field of edible fungi cultivation technology. Background Technology

[0002] Cicada flower, also known as cicada nymph grass or cicada velvet, is a type of cordyceps formed by the fungus *Isaria cicadae* Miquel, a member of the Cordyceps family, parasitizing the nymphs of cicadas. Natural cicada flower resources are extremely limited, and their quality cannot be guaranteed due to variations in origin, harvesting time, susceptibility to contamination and mold growth by other fungi, and excessive heavy metal content. Artificial cultivation of cicada flower primarily utilizes solid-state fermentation. Grains are used as a culture medium, and *Isaria cicadae* Miquel is inoculated into shake flasks or fermentation tanks via slant seed culture. Through solid-state fermentation, it forms flower-like, multi-branched fruiting bodies or powdery spores.

[0003] Currently, artificially cultivated cicada nymph fruiting bodies have been approved as new food ingredients. The cultivation process generates a large amount of solid culture medium residue—cicada nymph mycelium—containing abundant cicada nymph mycelium and residual grain nutrients. Currently, the utilization of cicada nymph mycelium is mostly focused on its development as animal feed. Existing technologies for recycling cicada nymph mycelium still generate a large amount of secondary mycelium, failing to achieve full utilization.

[0004] Current processes for preparing fungal organic selenium primarily involve adding inorganic selenium to solid or liquid culture media to enrich the fungi. The mechanism of action of fungal organic selenium in the human body is through selenoproteins, playing a crucial role in human health. Selenium deficiency can lead to various diseases such as diabetes, cardiovascular disease, and acute myocarditis. The fungal organic selenium industry offers significant economic, ecological, and social benefits. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a comprehensive utilization method for *Cicada nymph* mycelium. This method uses the solid culture medium remaining after the initial harvest of *Cicada nymph* fruiting bodies (primary mycelium) as raw material, adds selenium to produce selenium-enriched *Cicada nymph* spore powder or fruiting bodies; and then adds selenium to the remaining solid culture medium remaining after harvesting the selenium-enriched *Cicada nymph* spore powder or fruiting bodies (secondary mycelium) to produce fungal organic selenium raw material. The selenium-enriched *Cicada nymph* spore powder, selenium-enriched *Cicada nymph* fruiting bodies, and fungal organic selenium raw material obtained using the method of this invention are not only rich in selenium but also have significantly reduced harmful heavy metal content.

[0006] As one aspect of the present invention, the present invention provides a method for the comprehensive utilization of cicada flower mycelium, the method comprising the following steps:

[0007] Step 1, primary mycelium treatment: Take the solid culture medium remaining after the first harvest of cicada fruiting bodies, which is the primary mycelium. Dry it, add water and selenium salt to obtain the treated primary mycelium.

[0008] Step 2, Cultivation of selenium-enriched cicada fruiting bodies or spores: Take the primary mycelium from Step 1, inoculate it with cicada liquid spawn, carry out solid culture, and harvest the fruiting bodies or spores to obtain selenium-enriched cicada fruiting bodies or spores; collect the remaining solid culture medium to obtain secondary mycelium.

[0009] Step 3, secondary bacterial culture treatment: Take the secondary bacterial culture obtained in Step 2, dry it, add water and selenium salt to obtain the treated secondary bacterial culture;

[0010] Step 4, Preparation of fungal organic selenium: Take the secondary mycelium from step 3, inoculate it with Cordyceps militaris liquid inoculum, and culture it in the dark. When the culture medium turns grayish-white, harvest the culture medium to obtain fungal organic selenium raw material.

[0011] Preferably, step 1 further includes adding a grain additive, wherein the grain additive is selected from wheat flour, oat flour, or barley flour; more preferably, the amount of grain additive added is 5% to 50% (by weight) of the microbial matter; even more preferably, the amount of grain additive added is 10% to 40% (by weight) of the microbial matter; most preferably, the amount of grain additive added is 20% to 30% (by weight) of the microbial matter. When grain additive is added to the microbial matter, the amount of microbial matter is calculated as the total amount of microbial matter and grain additive.

[0012] Preferably, the selenium salt in step 1 is selected from inorganic selenium salts or organic selenium. Inorganic selenium salts include selenite and selenate; organic selenium includes yeast selenium.

[0013] Preferably, the amount of selenium salt added in step 1 is 5-70 mg per kilogram of mycelium; more preferably, the amount of selenium salt added is 10-60 mg per kilogram of mycelium; and even more preferably, the amount of selenium salt added is 20-50 mg per kilogram of mycelium.

[0014] Preferably, the solid culture medium in step 1 is a culture medium with any one or more of the following grains or crop hulls as the main raw materials: wheat, corn, rice, millet, buckwheat, barley, oats, brown rice, and japonica rice; or any one or more of the following crop hulls: wheat bran, soybean hulls, and cottonseed hulls. More preferably, it is an oat culture medium.

[0015] Preferably, the substrate-to-water ratio of the primary mycelium obtained in step 1 is 1:(0.6-1). More preferably, the substrate-to-water ratio depends on the culture; when using cicada spore powder as the culture, the substrate-to-water ratio is 1:(0.7-0.8); when using cicada fruiting bodies as the culture, the substrate-to-water ratio is 1:(0.9-1).

[0016] Preferably, the drying in step 1 is performed using a fluidized bed drying method, with a drying temperature of 60–100°C and a drying time of 40–120 min; more preferably, the drying temperature is 70–90°C and the drying time is 60–100 min; most preferably, the drying temperature is 80°C and the drying time is 80 min. The dried mycelium is then sieved to remove large mycelial clumps or aggregated mycelial masses; preferably, it is sieved through a 5-mesh sieve.

[0017] Preferably, the inoculation amount of the liquid cicadae culture in step 2 is 15%-20%; more preferably, the inoculation amount is 20%.

[0018] Preferably, the culture conditions for solid culture in step 2 depend on the culture medium. When using cicada spore powder as the culture medium, the culture temperature is 22-26℃, the humidity is 40-60%, the culture time in the dark stage is 5-7 days, the light intensity in the light stage is 50-400 Lux, and the overall culture time is 20-23 days. When using cicada fruiting bodies as the culture medium, the culture temperature is 20-26℃, the humidity is 60-80%, the culture time in the dark stage is 5-7 days, the light intensity in the light stage is 50-200 Lux, and the overall culture time is 20-23 days.

[0019] Preferably, step 3 further includes adding a cereal additive, wherein the cereal additive is selected from wheat flour, oat flour, or barley flour; more preferably, the amount of cereal additive added is 5% to 50% (by weight) of the microbial matter; even more preferably, the amount of cereal additive added is 10% to 40% (by weight) of the microbial matter; most preferably, the amount of cereal additive added is 20% to 30% (by weight) of the microbial matter. When a cereal additive is added to the microbial matter, the amount of microbial matter is calculated as the total amount of microbial matter and cereal additive.

[0020] Preferably, the selenium salt in step 3 is selected from inorganic selenium salts or organic selenium. Inorganic selenium salts include selenite and selenate; organic selenium includes yeast selenium.

[0021] Preferably, the amount of selenium salt added in step 3 is 70-300 mg per kilogram of mycelium; more preferably, the amount of selenium salt added is 90-250 mg per kilogram of mycelium; and most preferably, the amount of selenium salt added is 100-240 mg per kilogram of mycelium.

[0022] Preferably, the material-to-water ratio of the secondary microbial culture obtained in step 3 is 1:(0.7-0.9); more preferably, the material-to-water ratio is 1:0.8.

[0023] Preferably, the drying in step 3 is carried out using a fluidized bed drying method, with a drying temperature of 60-100℃ and a drying time of 40-120 min; more preferably, the drying temperature is 70-90℃ and the drying time is 60-100 min; most preferably, the drying temperature is 80℃ and the drying time is 80 min.

[0024] Preferably, the inoculation amount of the liquid cicadae culture in step 4 is 15%-20%; further, the inoculation amount is 20%.

[0025] Preferably, the culture conditions for dark culture in step 4 are: culture temperature 22-26℃, humidity 40-60%.

[0026] The "mycelium" mentioned in this invention refers to the solid culture residues remaining after solid culture and harvesting of cicada fruiting bodies during the artificial cultivation of cicada flowers.

[0027] The "solid culture" described in this invention includes a dark culture stage and a light culture stage performed sequentially. The dark culture stage is the mycelial growth stage. When the mycelium has fully grown the culture medium, it is switched to light culture. The light culture stage is the spore or fruiting body growth stage, and spores or fruiting bodies are obtained.

[0028] The "material-to-water ratio" mentioned in this invention is the weight / volume ratio (kg / L) of microbial matter to water; when grain additives are added, the amount of microbial matter is calculated as the total amount of microbial matter and grain additives.

[0029] The "Cicada Flower Liquid Culture" described in this invention refers to the mycelium obtained from the liquid-scale culture of Cicada Flower. This liquid-scale culture includes, but is not limited to, any one or more of the following culture methods: slant culture, shake flask culture, seed tank culture, and fermenter culture. The culture medium used for the liquid-scale culture is a conventional culture medium in the art, and the culture conditions are conventional culture conditions in the art.

[0030] The "inoculation amount of XX%" mentioned in this invention refers to the percentage of the inoculated Cordyceps militaris liquid strain (L) to the total amount of mycelium (kg); when grain additives are added, the amount of mycelium is calculated as the total amount of mycelium and grain additives.

[0031] The step of "adding selenium salt" in the method of this invention can be replaced by "adding other trace elements (such as chromium salt)" to produce cicada spore powder, cicada fruiting bodies and fungal organic trace element raw materials rich in other trace elements.

[0032] In this invention, unless otherwise stated, as is known in the art, in order to avoid contamination by microorganisms, all operations are preferably performed under substantially sterile conditions, and all tools and materials used are sterilized and should avoid introducing heavy metal elements.

[0033] The beneficial effects of this invention are:

[0034] ① This invention truly realizes the comprehensive utilization of *Cicada nymph* mycelium. The method for comprehensive utilization of *Cicada nymph* mycelium in this invention can completely consume the solid culture medium remaining from the artificial cultivation of *Cicada nymph*, without generating any waste or requiring waste treatment, thus truly realizing the comprehensive utilization of *Cicada nymph* mycelium.

[0035] ② Obtain high-quality selenium-enriched cicada spore powder, fruiting bodies, and fungal organic selenium. Using the comprehensive utilization method of cicada spore mycelium of this invention, the selenium-enriched cicada spore powder or fruiting bodies obtained from primary mycelium reculturing have comparable effective component content to those prepared by conventional processes, but significantly higher selenium content and significantly lower harmful heavy metal content. Furthermore, the secondary mycelium can be used to produce fungal organic selenium raw materials, which not only significantly increase selenium content but also have extremely low harmful heavy metal content, even lower than that found in wheat or oats, making it a safe dietary supplement.

[0036] ③ Significant economic benefits. The artificially cultivated *Cicada nymph* produces a very large quantity of mycelium. Many companies sell it directly to farms as feed at a price of several hundred yuan per ton for wet material, or dried for feed at approximately 2000 yuan per ton, which is very inexpensive. Using the method of this invention, taking the production of spore powder as an example, each ton of primary mycelium can produce at least 100 kg of high-quality spore powder, with a market value of 660,000 yuan, and also produce 500 kg of secondary mycelium. The secondary mycelium cultivation yields approximately 375 kg of fungal organic selenium raw material, including 112.5 kg of high-quality grayish-white raw material and 262.5 kg of darker-colored raw material, with a total value of 80,000 yuan. The combined value of the spore powder and organic selenium products is 740,000 yuan, while the cost of 1 ton of mycelium is only about 2000 yuan, and the total labor and energy costs are 15,000 yuan. Therefore, the direct economic benefits of this invention are very significant. Detailed Implementation

[0037] The present invention is further described below through specific embodiments, but the present invention is not limited to the following embodiments. Modifications, combinations, or substitutions made to the present invention within the scope of the present invention or without departing from the content, spirit, and scope of the present invention will be obvious to those skilled in the art and are included within the scope of the present invention.

[0038] The *Cicada nymph* strain used in the following examples is strain 17-7-1 (this strain has been disclosed in Chinese Patent 201110120603.1, accession number CGMCC No. 3453). The use of *Cicada nymph* strains does not constitute a limitation on the technical solution of this invention; any remaining primary mycelium from artificially cultured other *Cicada nymph* strains can be used in this invention to achieve the technical effects of this invention.

[0039] Example 1: Solid Culture of Cicada Flower

[0040] 1. Preparation of solid culture medium: After washing and draining the oats, add an appropriate amount of water at a weight ratio of oats:water of 1:1.4, and mix thoroughly. After mixing, pour the mixture into culture containers. Place the culture containers filled with culture medium in an autoclave and sterilize at 121℃ for 30-50 minutes. After sterilization, transfer the culture containers to a buffer chamber and allow them to cool naturally to below 24℃ before transferring them to the inoculation chamber.

[0041] 2. Inoculation: Before inoculation, the culture containers should be irradiated with ultraviolet light for 0.5 hours in a clean bench or a Class 100 laminar flow hood. Each culture container should be inoculated at a rate of 10%. After inoculation, the containers should be placed in the culture room for incubation.

[0042] 3. Culture conditions: During the dark culture stage, the culture temperature is 24±2℃; when the mycelium has fully colonized the culture medium, switch to light culture with a light intensity of 150 Lx, a culture room temperature of 22±2℃, and a relative humidity of 70±10%. The culture room should be ventilated in a timely manner to keep the air in the mycelium growth room fresh; harvest after 23-25 ​​days, when the sporangiophores are nearly mature but before a large number of spores have been produced.

[0043] 4 Harvested fruiting bodies

[0044] The sporophyte bundles were harvested; the harvested sporophyte bundles were then placed in a drying device for drying. The temperature was set at 60℃ and the drying time was 4 hours.

[0045] 5. Harvesting fungal substrate

[0046] The solid culture medium remaining after harvesting the fruiting bodies is called primary mycelium.

[0047] Example 2: Cultivation of selenium-enriched cicada spore powder using a single fungal culture

[0048] 1. Drying of fungal matter

[0049] The primary bacterial culture obtained in Example 1 was placed in a fluidized bed dryer. The dryer was started and the temperature was set to 80°C to heat the air. A fan was turned on to deliver hot air for drying. Drying was completed in about 80 minutes. The fluidized bed was then closed and the bacterial culture was collected; it was in granular form.

[0050] 2. Microbial sieving

[0051] After drying, the primary mycelial granules are passed through a 5-mesh sieve to remove large mycelial clumps or aggregated mycelial masses.

[0052] 3. Wheat flour preparation

[0053] Wheat is coarsely ground and passed through a 20-mesh sieve to obtain wheat flour.

[0054] 4. Preparation of solid culture medium for selenium-enriched cicada spore powder

[0055] 4.1 Mix the bacterial plasmid and 20% wheat flour evenly, and place 250g in a culture container;

[0056] 4.2 Prepare a 2.5 mg / ml sodium selenite aqueous solution. Take 5 ml of sodium selenite aqueous solution and 170 ml of water and add them to the culture container. Mix them evenly with the mycelial plasmid and wheat flour to prepare a solid culture medium containing 50 mg of sodium selenite per kilogram of mycelial material (based on the total amount of mycelial plasmid and wheat flour) and a material-to-water ratio of 1:0.7.

[0057] 4.3 Sterilize the solid culture medium at 121℃ for 30 min.

[0058] 5. Inoculation and culture

[0059] After sterilization, cool the culture container to room temperature, inoculate with 20% *Vitex negundo* spawn, and place it in a culture room for dark incubation, controlling the temperature at 24±2℃ and the relative humidity at 50±10%. After 5–7 days, when the mycelium has fully grown onto the surface of the culture medium, make holes (40–60 wells) for ventilation; if a breathable membrane is available, the hole-making step can be omitted. Then proceed with light incubation at a light intensity of 200 lux. The incubation period is 20–23 days.

[0060] 6. Harvest spores and mycelium

[0061] Connect the harvesting platform to the power supply, turn on the dust removal switch, and ensure ventilation. Open the harvesting hood's movable window, pour the culture from the culture bag into a non-porous drying tray, and dehumidify for 24 hours. Then, dry it at 80℃ for 8-12 hours. Sieve the dried culture containing spores (100-mesh sieve). The material passing through the sieve is the spore powder, and the material remaining on the sieve is the secondary mycelium.

[0062] Example 3: Cultivation of selenium-enriched cicada spore powder using a single fungal culture

[0063] The cultivation method is basically the same as in Example 2, except that wheat flour is not added and 5 mg of sodium selenite is added per kilogram of mycelium.

[0064] Example 4: Cultivation of selenium-enriched cicada spore powder using a single fungal culture

[0065] The cultivation method is basically the same as in Example 2, except that wheat flour is not added and 20 mg of sodium selenite is added per kilogram of mycelium.

[0066] The spore powder of *Cicada spores* cultured in Examples 2-4 was used to calculate the yield and spore content, and the contents of heavy metals and active ingredients were determined. The results are shown in Tables 1 and 2.

[0067] Table 1. Yield, spore content, heavy metal and trace element content of *Cicada spore powder* obtained from a single mycelial culture.

[0068]

[0069] Note: Yield % = Dry weight of spore powder / Initial dry weight of mycelium consumed at one time × 100%.

[0070] *The production process of the control spore powder: wheat was used as the solid culture medium raw material, the material-to-water ratio was 1:0.7, and the culture conditions were: dark culture temperature of 25℃, culture time of 4 days; then switched to light culture, light intensity of 150 Lux, culture temperature of 25℃, culture time of 21 days (including dark culture time).

[0071] Table 2. Content of effective components in cicada spore powder obtained from a single mycelial culture.

[0072] Example Adenosine (%) HEA (%) Polysaccharides (%) Spore powder control* 0.16Aa 0.80Aa 2.6Aa 2 0.16Aa 0.82Aa 2.5Aa 3 0.15Aa 0.90Aa 2.3Aa 4 0.15Aa 0.81Aa 2.3Aa

[0073] Note: HEA refers to N. 6 -(2-hydroxyethyl)adenosine.

[0074] As shown in Tables 1 and 2, the selenium content of the cicada spore powder obtained by single-stage mycelial culture was significantly increased, and the content of harmful heavy metals cadmium and lead was extremely low, which was an order of magnitude lower than that of spore powder prepared by ordinary process; while the yield, spore content, and content of effective ingredients were comparable to those of spore powder prepared by ordinary process.

[0075] Example 5: Cultivation of selenium-enriched cicada fruiting bodies using primary mycelial culture

[0076] 1. Fluidized bed drying

[0077] The bacterial culture obtained in Example 1 was placed in a fluidized bed dryer. The dryer was started and the temperature was set to 80°C to heat the air. A fan was turned on to deliver hot air for drying. Drying was completed in about 80 minutes. The fluidized bed was then closed and the bacterial culture was collected; it was in granular form.

[0078] 2. Microbial sieving

[0079] The dried mycelial granules were passed through a 5-mesh sieve to remove large mycelial clumps or aggregated mycelial masses.

[0080] 3. Wheat flour preparation

[0081] Wheat is coarsely ground and passed through a 20-mesh sieve to obtain wheat flour.

[0082] 4. Preparation of solid culture medium for selenium-enriched cicada fruiting bodies

[0083] 4.1 Mix the bacterial plasmid and 30% wheat flour evenly, and place 250g in a culture container;

[0084] 4.2 Prepare a 2.5 mg / ml sodium selenite aqueous solution. Take 5 ml of sodium selenite aqueous solution and 220 ml of water and add them to the culture container. Mix them evenly with the mycelial plasmid and wheat flour to prepare a solid culture medium containing 50 mg of sodium selenite per kilogram of mycelial material (based on the total amount of mycelial plasmid and wheat flour) and a material-to-water ratio of 1:0.9.

[0085] 4.3 Sterilize the solid culture medium at 121℃ for 30 min.

[0086] 5. Inoculation and culture

[0087] After sterilization, the culture container is cooled to room temperature, inoculated with 20% *Cicada nymph* spawn, and placed in a culture room for dark cultivation at a controlled temperature of 24±2℃. After 5–7 days, when the mycelium has fully grown onto the surface of the culture medium, holes (40–60 holes) are punched for ventilation, maintaining a controlled temperature of 22±2℃ and a relative humidity of 70±10%. If a breathable membrane is available, the hole-punching step can be omitted. Then, light cultivation is carried out at a light intensity of 150 lux. After 23 days of cultivation, the fruiting bodies are harvested, dried, and the selenium-enriched *Cicada nymph* fruiting bodies are obtained.

[0088] 6. Harvesting fungal substrate

[0089] The solid culture medium remaining after harvesting the fruiting bodies is called secondary mycelium.

[0090] Example 6: Cultivation of selenium-enriched cicada fruiting bodies using primary mycelial culture

[0091] The cultivation method is basically the same as in Example 5, except that 40% wheat flour is added.

[0092] Example 7: Cultivation of selenium-enriched cicada fruiting bodies using primary mycelial culture

[0093] The cultivation method is basically the same as in Example 5, except that 50% wheat flour is added.

[0094] The fruiting bodies of cicada flowers cultured in Examples 5-7 were used to calculate the yield and determine the content of heavy metals and active ingredients. The results are shown in Tables 3 and 4.

[0095] Table 3. Yield of Cordyceps sinensis fruiting bodies, heavy metal and trace element content from single-stage mycelial culture.

[0096]

[0097] Note: Yield % = Dry weight of fruiting bodies / Initial dry weight of mycelium consumed at one time × 100%.

[0098] *The sub-entity comparison is the sub-entity obtained using Example 1.

[0099] Table 4. Content of effective components in cicada fruiting bodies from a single mycelial culture.

[0100] Example Adenosine (%) HEA (%) Polysaccharides (%) Sub-entity comparison* 0.17Aa 0.10Cc 4.9Aa 5 0.12Bb 0.21Aa 4.8Aa 6 0.11Bb 0.18Bb 4.6Aa 7 0.12Bb 0.15Bb 4.8Aa

[0101] Note: HEA refers to N. 6 -(2-hydroxyethyl)adenosine.

[0102] As shown in Tables 3 and 4, the selenium content of the fruiting bodies of Cordyceps sinensis obtained by a single culture was significantly increased, while the contents of harmful heavy metals cadmium and lead were extremely low. Compared with the fruiting bodies prepared by the ordinary process, the cadmium content was reduced by an order of magnitude, and the lead content was reduced by 1 / 4. The yield and the content of effective ingredients were comparable to those of the fruiting bodies prepared by the ordinary process.

[0103] Example 8: Preparation of fungal organic selenium raw material using secondary mycelium

[0104] 1. Fluidized bed drying

[0105] The secondary bacterial culture obtained in Example 2 was placed in a fluidized bed dryer. The dryer was started and the temperature was set to 80°C to heat the air. A fan was turned on to deliver hot air for drying. Drying was completed in about 80 minutes. The fluidized bed was then closed and the bacterial culture was collected; it was in granular form.

[0106] 2. Microbial sieving

[0107] The dried mycelial granules were passed through a 5-mesh sieve to remove large mycelial clumps or aggregated mycelial masses.

[0108] 3. Wheat flour preparation

[0109] Wheat is coarsely ground and passed through a 20-mesh sieve to obtain wheat flour.

[0110] 4. Preparation of solid culture medium for selenium-enriched cicada spore powder

[0111] 4.1 Mix the bacterial plasmid and 30% wheat flour evenly, and place 250g in a culture container;

[0112] 4.2 Prepare a 2.5 mg / ml sodium selenite aqueous solution. Take 10 ml of sodium selenite aqueous solution and 190 ml of water and add them to the culture container. Mix them evenly with the bacterial plasmid and wheat flour to prepare a solid culture medium containing 100 mg of sodium selenite per kilogram of bacterial plasmid (based on the total amount of bacterial plasmid and wheat flour) and a material-to-water ratio of 1:0.8.

[0113] 4.3 Sterilize the solid culture medium at 121℃ for 30 min.

[0114] 5. Inoculation and culture

[0115] After sterilization, the culture container was cooled to room temperature, inoculated with 20% of Cordyceps militaris, and placed in a culture room for dark culture at a temperature of 24±2℃ and a relative humidity of 50±10%. After the Cordyceps militaris mycelium fermented completely and the culture medium turned grayish-white, it was harvested, cut into pieces, dried, crushed, and graded to obtain different grades of fungal organic selenium raw materials.

[0116] Example 9: Preparation of fungal organic selenium raw material using secondary mycelium

[0117] The cultivation method is basically the same as in Example 8, except that wheat flour is not added and 160 mg of sodium selenite is added per kilogram of mycelium.

[0118] Example 10: Preparation of fungal organic selenium raw material using secondary mycelium

[0119] The secondary bacterial culture obtained in Example 5 was cultured using the same method as in Example 8, except that wheat flour was not added and 240 mg of sodium selenite was added per kilogram of bacterial culture.

[0120] The yield of the fungal organic selenium premium raw material (graded grayish-white) prepared in Examples 8-10 was calculated and the heavy metal content was determined. The results are shown in Table 5.

[0121] Table 5. Yield, heavy metal and trace element content of premium fungal organic selenium raw material from secondary mycelial culture.

[0122]

[0123] Note: Yield % = Dry weight of premium organic selenium fungal raw material / Initial dry weight of fungal culture consumed at one time × 100%.

[0124] As shown in Table 5, the fungal organic selenium raw material obtained from secondary culture has extremely low levels of harmful heavy metals cadmium and lead, even lower than the heavy metal content in wheat and oats, and is rich in selenium, making it a safe dietary supplement for selenium.

Claims

1. A comprehensive utilization method of mycelia of Cordyceps, characterized in that, The method comprises the following steps: Step 1, treatment of the primary mycelium: taking the solid culture medium left after the initial collection of Cordyceps cicadae fruiting bodies as the primary mycelium, drying, adding water and selenium salt to obtain the treated primary mycelium; Step 2, culture of selenium-rich Cordyceps cicadae fruiting bodies or spore powder: taking the treated primary mycelium obtained in step 1, inoculating Cordyceps cicadae liquid culture, and performing solid culture to obtain selenium-rich Cordyceps cicadae fruiting bodies or spore powder; collecting the remaining solid culture medium to obtain secondary mycelium; Step 3, treatment of the secondary mycelium: taking the secondary mycelium obtained in step 2, drying, adding water and selenium salt to obtain the treated secondary mycelium; Step 4, preparation of fungal organic selenium: taking the treated secondary mycelium obtained in step 3, inoculating Cordyceps cicadae liquid culture, and performing dark culture until the culture medium turns grayish white, and then collecting the culture medium to obtain the raw material of fungal organic selenium.

2. The method of claim 1, wherein, Step 1 or step 3 further comprises adding a grain additive selected from wheat flour, oat flour or barley flour; preferably, the grain additive is added in an amount of 5% to 50% of the mycelium; further preferably, the grain additive is added in an amount of 10% to 40% of the mycelium; most preferably, the grain additive is added in an amount of 20% to 30% of the mycelium. When the grain additive is added to the mycelium, the amount of the mycelium is calculated based on the total amount of the mycelium and the grain additive.

3. The method of claim 1, wherein, The selenium salt in step 1 or step 3 is selected from inorganic selenium salt or organic selenium, wherein the inorganic selenium salt includes selenite and selenate; and the organic selenium includes yeast selenium.

4. The method of claim 1, wherein, The amount of the selenium salt added in step 1 is 5 to 70 mg per kilogram of mycelium; preferably, the amount of the selenium salt added is 10 to 60 mg per kilogram of mycelium; further preferably, the amount of the selenium salt added is 20 to 50 mg per kilogram of mycelium.

5. The method of claim 1, wherein, The ratio of the treated primary mycelium obtained in step 1 to water is 1:(0.6 to 1); preferably, the ratio of the culture to water is 1:(0.7 to 0.8) when the culture is Cordyceps cicadae spore powder; and the ratio of the culture to water is 1:(0.9 to 1) when the culture is Cordyceps cicadae fruiting bodies.

6. The method of claim 1, wherein, The drying in step 1 or step 3 is performed by using a fluidized bed drying method, wherein the drying temperature is 60 to 100°C, and the drying time is 40 to 120 minutes; preferably, the drying temperature is 70 to 90°C, and the drying time is 60 to 100 minutes; most preferably, the drying temperature is 80°C, and the drying time is 80 minutes.

7. The method of claim 1, wherein, The culture conditions of the solid culture in step 2 are determined according to the culture, wherein when the culture is Cordyceps cicadae spore powder, the culture temperature is 22 to 26°C, the humidity is 40 to 60%, the dark culture time is 5 to 7 days, the light intensity in the light culture stage is 50 to 400 Lux, and the overall culture time is 20 to 23 days; and when the culture is Cordyceps cicadae fruiting bodies, the culture temperature is 20 to 26°C, the humidity is 60 to 80%, the dark culture time is 5 to 7 days, the light intensity in the light culture stage is 50 to 200 Lux, and the overall culture time is 20 to 23 days.

8. The method of claim 1, wherein, The selenium salt is added in an amount of 70-300 mg per kg of the bacterial mass; preferably, the selenium salt is added in an amount of 90-250 mg per kg of the bacterial mass; further preferably, the selenium salt is added in an amount of 100-240 mg per kg of the bacterial mass.

9. The method of claim 1, wherein, The ratio of the treated secondary bacterial mass to water obtained in step 3 is 1: (0.7-0.9); preferably, the ratio of the treated secondary bacterial mass to water is 1:0.

8.

10. The method of claim 1, wherein, The culture conditions of the dark culture in step 4 are as follows: culture temperature 22-26 °C, humidity 40-60%.

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