Cultivation method of strontium-enriched cordyceps militaris

Abstract

The invention discloses a culture method of strontium-rich cordyceps militaris, and relates to the technical field of microorganism culture, the culture method comprises the following steps: step S1, preparation of a culture medium; step S2, activating a strain; s3, culturing a liquid seed solution; s4, performing solid culture; and step S5, harvesting and drying. According to the strontium-enriched cordyceps militaris cultivated through the cultivation method of the strontium-enriched cordyceps militaris, efficient enrichment of the strontium element can be achieved, and the biomass and the core active ingredient content of the cordyceps militaris can be guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microbial cultivation, in particular to a cultivation method of strontium-rich Cordyceps militaris. BACKGROUND

[0002] Cordyceps militaris, also known as North Cordyceps, is a precious fungus with both medicinal and edible values. It contains active ingredients such as cordycepin, adenosine, and polysaccharides, which have physiological functions such as immune regulation, antioxidant, and anti-fatigue, and are widely used in health food and medicine fields. However, the natural Cordyceps militaris has limited ability to enrich trace elements, which cannot meet the specific nutritional supplement needs.

[0003] With the improvement of consumer health needs, Cordyceps militaris products rich in beneficial minerals have gradually become a market hotspot. Strontium, as one of the essential trace elements for the human body, has attracted much attention. Strontium participates in bone formation, regulates neuromuscular excitability, and improves cardiovascular function in the human body, and can also synergize with calcium to reduce the risk of diseases such as osteoporosis and hypertension. However, since strontium is an exogenous ion, excessive addition will damage the cell membrane structure of Cordyceps militaris mycelium, inhibit the activity of metabolic enzymes, and lead to slow growth and reduced biomass of mycelium. Traditional culture medium formula (such as single carbon source and simple nitrogen source combination) lacks synergistic effect on strontium ion absorption and transport, resulting in low strontium enrichment efficiency and easy reduction of the content of core active ingredients such as cordycepin and adenosine. Therefore, the current strontium-rich Cordyceps militaris has limited yield, low content of nutritional ingredients, and uneven quality, which cannot meet people's needs.

[0004] Therefore, it is particularly important to develop a cultivation method of strontium-rich Cordyceps militaris that can achieve efficient enrichment of strontium elements and ensure the biomass and content of core active ingredients of Cordyceps militaris. SUMMARY

[0005] The present application aims to overcome the problems of the prior art and provide a cultivation method of strontium-rich Cordyceps militaris that can achieve efficient enrichment of strontium elements and ensure the biomass and content of core active ingredients of Cordyceps militaris.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: a cultivation method of strontium-rich Cordyceps militaris, comprising the following steps: Step S1, preparation of culture medium: dissolve each component in purified water according to the liquid seed culture medium formula, mix uniformly, pour into a culture bottle, seal, sterilize, cool, and obtain a liquid seed culture medium; prepare a solid culture medium according to the solid culture medium formula; Step S2, strain activation: inoculate Cordyceps militaris strain on PDA slant culture medium, incubate at 20-22℃ for 7-10 days, and then rinse the mycelium with sterile physiological saline to obtain a bacterial suspension; Step S3, liquid seed liquid culture: the bacterial suspension is inoculated into a liquid seed culture medium, and is placed in a shaking bed for 3-5 days of vibration culture at 20-22°C and 150-180r / min, to obtain a liquid seed liquid; Step S4, solid culture: the liquid seed liquid is uniformly sprayed on the surface of a solid culture medium, and is placed in a culture box for solid culture; Step S5, harvesting and drying: after the Cordyceps militaris fruiting body matures, the fruiting body and mycelium are harvested, rinsed with clean water to remove surface impurities, vacuum dried at 55-65°C until constant weight, crushed through an 80-100 mesh sieve, to obtain a strontium-rich Cordyceps militaris product.

[0007] Preferably, the liquid seed culture medium in step S1 is composed of the following components in the following amounts: glucose 20-25g / L, peptone 10-12g / L, yeast extract 3-5g / L, strontium nitrate 0.5-0.8g / L, strontium citrate 0.3-0.5g / L, complex nutritional elements 0.5-0.8g / L, vitamin B1 0.05-0.1g / L, vitamin B6 0.03-0.05g / L, calcium carbonate 0.6-1.2g / L, ferrous sulfate 0.07-0.12g / L, silkworm pupa polypeptide powder 6-8g / L, L-proline 0.1-0.2g / L, and fructooligosaccharide 5-8g / L, with the pH adjusted to 5.5-6.5.

[0008] Preferably, the complex nutritional elements are composed of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:2:1.

[0009] Preferably, the solid culture medium in step S1 is composed of the following components in the following amounts: wheat grains 60-70 parts, silkworm pupa powder 15-20 parts, corn flour 5-8 parts, glucose 3-5 parts, strontium chloride 0.5-0.8 parts, strontium citrate 0.3-0.5 parts, a complex synergist 0.3-0.5 parts, rice flour 40-50 parts, barley sprout powder 10-20 parts, plant polysaccharide 5-8 parts, and water 120-150 parts, with the pH adjusted to 5.8-6.2.

[0010] Preferably, the complex synergist is composed of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:3:1.

[0011] Preferably, the plant polysaccharide is at least one of tea polysaccharide, medlar polysaccharide, and lentinan.

[0012] Preferably, the sterilization temperature in step S1 is 121°C, and the sterilization time is 30 minutes.

[0013] Preferably, the Cordyceps militaris strain in step S2 is ACCC50632.

[0014] Preferably, the concentration of the bacteria in the bacterial suspension in step S2 is 1x106 -5 x 10 6 cfu / mL.

[0015] Preferably, the inoculation amount of the bacterial suspension in step S3 is 5-8 vol.%.

[0016] Preferably, the inoculation amount of the liquid seed solution in step S4 is 10-15 vol.%.

[0017] Preferably, the culture conditions of the solid culture in step S4 are as follows: temperature 18-22℃, relative humidity 60-70%, light intensity 1500-2000 lux, light cycle 12h light / 12h dark, 2 hours of blue light irradiation per day, and culture time 55-65 days.

[0018] Preferably, the maturity of the Cordyceps militaris fruiting body in step S5 is that the stipe length is more than 8 cm.

[0019] Due to the use of the above technical solutions, the present application has the following beneficial effects: (1) The "strontium nitrate + strontium citrate" composite strontium source is used, strontium citrate can reduce the toxicity of free strontium ions through complexation, and at the same time form absorption complementation with strontium nitrate; simultaneously, biological active components such as silkworm chrysalis polypeptide powder, L-proline and fructooligosaccharide are introduced, the silkworm chrysalis polypeptide powder participates in the synthesis of cell membrane phospholipids to enhance the structural stability, L-proline regulates the cell osmotic pressure to improve the strontium tolerance, and fructooligosaccharide activates the activity of hexokinase to strengthen the carbon source utilization efficiency, and the three components synergistically improve the mycelium dry weight and the initial strontium absorption efficiency.

[0020] (2) Rice powder, barley sprout powder and plant polysaccharides (tea polysaccharides, Chinese wolfberry polysaccharides, etc.) are combined and added in the solid culture medium, the rice powder provides a slow-release carbon source to prolong the nutrient supply period, the natural vitamins and minerals in the barley sprout powder activate the enzyme activity related to strontium transport, and the plant polysaccharides remove active oxygen induced by strontium through antioxidant effect; in addition, the "magnesium sulfate + zinc sulfate + selenomethionine = 5:3:1" composite synergist is used, zinc ions promote the differentiation of fruiting bodies, and selenium ions protect the synthesis pathway of cordycepin, so that the contents of cordycepin and adenosine in the product are high, and at the same time, the final strontium enrichment amount is large.

[0021] (3) Based on the physiological characteristics of Cordyceps militaris at different culture stages, a differential system is designed: in the liquid seed stage, low-concentration composite strontium source is used in combination with composite trace elements, focusing on mycelium proliferation and strontium tolerance domestication; in the solid culture stage, the strontium source concentration is increased and a composite synergist is introduced, focusing on strontium accumulation and active ingredient synthesis of fruiting bodies, and the strontium source concentration is controlled within a safe threshold value throughout the process, avoiding the safety risks caused by blind concentration in the prior art.

[0022] (4) By rationally selecting the liquid seed culture medium and solid culture medium formula, the components can work together to achieve the same effect. At the same time, by optimizing the specific process parameters in the cultivation method, the product can achieve both efficient enrichment of strontium and ensure the biomass and content of core active ingredients of Cordyceps militaris. Detailed Implementation

[0023] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0024] Example 1 A method for cultivating strontium-enriched Cordyceps militaris includes the following steps: Step S1: Preparation of culture medium: Dissolve each component in pure water according to the liquid seed culture medium formula, mix evenly, pour into culture flasks, seal, sterilize, and cool to obtain liquid seed culture medium; prepare solid culture medium according to the solid culture medium formula. Step S2, strain activation: Take Cordyceps militaris strain and inoculate it into PDA slant medium. Incubate at 20℃ for 7 days. After the mycelium has covered the slant, wash with sterile physiological saline to obtain a bacterial suspension. Step S3, Liquid seed culture: Inoculate the bacterial suspension into liquid seed culture medium, place it in a shaker, and culture at 20℃ and 150r / min for 3 days to obtain liquid seed culture; Step S4, Solid Culture: Spray the liquid seed solution evenly onto the surface of the solid culture medium and place it in an incubator for solid culture; Step S5, Harvesting and Drying: After the fruiting bodies of Cordyceps militaris mature, harvest the fruiting bodies and mycelium, rinse with clean water to remove surface impurities, vacuum dry at 65℃ to constant weight, pulverize and pass through an 80-mesh sieve to obtain strontium-rich Cordyceps militaris product.

[0025] The liquid seed culture medium described in step S1 consists of the following components in the following proportions: glucose 20 g / L, peptone 10 g / L, yeast extract 3 g / L, strontium nitrate 0.5 g / L, strontium citrate 0.3 g / L, compound nutrients 0.5 g / L, vitamin B1 0.05 g / L, vitamin B6 0.03 g / L, calcium carbonate 0.6 g / L, ferrous sulfate 0.07 g / L, silkworm pupa polypeptide powder 6 g / L, L-proline 0.1 g / L, and fructooligosaccharides 5 g / L, with the pH adjusted to 5.5; the compound nutrients consist of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:2:1.

[0026] The solid culture medium in step S1 is composed of the following components in the following proportions: 60 parts wheat grains, 15 parts silkworm pupa powder, 5 parts corn flour, 3 parts glucose, 0.5 parts strontium chloride, 0.3 parts strontium citrate, 0.3 parts compound synergist, 40 parts rice flour, 10 parts barley seedling powder, 5 parts plant polysaccharide, and 120 parts water, with the pH adjusted to 5.8; the compound synergist is composed of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:3:1; the plant polysaccharide is tea polysaccharide.

[0027] The sterilization temperature in step S1 is 121℃, and the time is 30 min; the Cordyceps militaris strain in step S2 is ACCC50632; the bacterial concentration in the bacterial suspension in step S2 is 1×10⁻⁶. 6 cfu / mL; the inoculation volume of the bacterial suspension in step S3 is 5 vol.%; the inoculation volume of the liquid seed solution in step S4 is 10 vol.%; the culture conditions for solid culture in step S4 are: temperature 18℃, relative humidity 60%, light intensity 1500 lux, photoperiod 12h light / 12h dark, 2 hours of blue light irradiation per day, culture for 55 days; the maturity of the Cordyceps militaris fruiting body in step S5 is when its stroma length is more than 8 cm.

[0028] Example 2 A method for cultivating strontium-enriched Cordyceps militaris includes the following steps: Step S1: Preparation of culture medium: Dissolve each component in pure water according to the liquid seed culture medium formula, mix evenly, pour into culture flasks, seal, sterilize, and cool to obtain liquid seed culture medium; prepare solid culture medium according to the solid culture medium formula. Step S2, strain activation: Take Cordyceps militaris strain and inoculate it into PDA slant medium. Incubate at 20.5℃ for 8 days. After the mycelium has covered the slant, wash it with sterile physiological saline to obtain a bacterial suspension. Step S3, Liquid seed culture: Inoculate the bacterial suspension into the liquid seed culture medium, place it in a shaker, and culture at 20.5℃ and 160r / min for 3.5 days to obtain the liquid seed culture; Step S4, Solid Culture: Spray the liquid seed solution evenly onto the surface of the solid culture medium and place it in an incubator for solid culture; Step S5, Harvesting and Drying: After the fruiting bodies of Cordyceps militaris mature, harvest the fruiting bodies and mycelium, rinse with clean water to remove surface impurities, vacuum dry at 65℃ to constant weight, pulverize and pass through an 85-mesh sieve to obtain strontium-rich Cordyceps militaris product.

[0029] The liquid seed culture medium described in step S1 consists of the following components in the following proportions: glucose 22 g / L, peptone 10.5 g / L, yeast extract 3.5 g / L, strontium nitrate 0.6 g / L, strontium citrate 0.35 g / L, compound nutrients 0.6 g / L, vitamin B1 0.06 g / L, vitamin B6 0.035 g / L, calcium carbonate 0.7 g / L, ferrous sulfate 0.08 g / L, silkworm pupa polypeptide powder 6.5 g / L, L-proline 0.13 g / L, and fructooligosaccharides 6 g / L, with the pH adjusted to 5.8; the compound nutrients consist of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:2:1.

[0030] The solid culture medium in step S1 is composed of the following components in the following proportions: 63 parts wheat grains, 17 parts silkworm pupa powder, 6 parts corn flour, 3.5 parts glucose, 0.6 parts strontium chloride, 0.35 parts strontium citrate, 0.35 parts compound synergist, 43 parts rice flour, 13 parts barley grass powder, 6 parts plant polysaccharide, and 130 parts water, with the pH adjusted to 5.9; the compound synergist is composed of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:3:1; the plant polysaccharide is wolfberry polysaccharide.

[0031] The sterilization temperature in step S1 is 121℃, and the time is 30 min; the Cordyceps militaris strain in step S2 is ACCC50632; the bacterial concentration in the bacterial suspension in step S2 is 2×10⁻⁶. 6 cfu / mL; the inoculation volume of the bacterial suspension in step S3 is 6 vol.%; the inoculation volume of the liquid seed solution in step S4 is 12 vol.%; the culture conditions for solid culture in step S4 are: temperature 19℃, relative humidity 63%, light intensity 1600 lux, photoperiod 12h light / 12h dark, 2 hours of blue light irradiation per day, culture for 57 days; the maturity of the Cordyceps militaris fruiting body in step S5 is when its stroma length is more than 8 cm.

[0032] Example 3 A method for cultivating strontium-enriched Cordyceps militaris includes the following steps: Step S1: Preparation of culture medium: Dissolve each component in pure water according to the liquid seed culture medium formula, mix evenly, pour into culture flasks, seal, sterilize, and cool to obtain liquid seed culture medium; prepare solid culture medium according to the solid culture medium formula. Step S2, strain activation: Inoculate the Cordyceps militaris strain onto PDA slant medium and incubate at 21℃ for 8.5 days. After the mycelium has covered the slant, rinse with sterile physiological saline to obtain a bacterial suspension. Step S3, Liquid seed culture: Inoculate the bacterial suspension into the liquid seed culture medium, place it in a shaker, and culture at 21℃ and 165r / min for 4 days to obtain the liquid seed culture; Step S4, Solid Culture: Spray the liquid seed solution evenly onto the surface of the solid culture medium and place it in an incubator for solid culture; Step S5, Harvesting and Drying: After the fruiting bodies of Cordyceps militaris mature, harvest the fruiting bodies and mycelium, rinse with clean water to remove surface impurities, vacuum dry at 65℃ to constant weight, pulverize and pass through a 90-mesh sieve to obtain strontium-rich Cordyceps militaris product.

[0033] The liquid seed culture medium in step S1 consists of the following components in the following proportions: glucose 23 g / L, peptone 11 g / L, yeast extract 4 g / L, strontium nitrate 0.65 g / L, strontium citrate 0.4 g / L, compound nutrients 0.65 g / L, vitamin B1 0.08 g / L, vitamin B6 0.04 g / L, calcium carbonate 0.9 g / L, ferrous sulfate 0.09 g / L, silkworm pupa polypeptide powder 7 g / L, L-proline 0.15 g / L, and fructooligosaccharides 6.5 g / L, with the pH adjusted to 6; the compound nutrients consist of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:2:1.

[0034] The solid culture medium in step S1 consists of the following components in the following proportions: 65 parts wheat grains, 18 parts silkworm pupa powder, 6.5 parts corn flour, 4 parts glucose, 0.65 parts strontium chloride, 0.4 parts strontium citrate, 0.4 parts compound synergist, 45 parts rice flour, 15 parts barley sprout powder, 6.5 parts plant polysaccharide, and 135 parts water, adjusted to pH 6; the compound synergist is composed of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:3:1; the plant polysaccharide is lentinan; the sterilization temperature in step S1 is 121℃, and the time is 30 min; the Cordyceps militaris strain in step S2 is ACCC50632; the bacterial concentration in the bacterial suspension in step S2 is 3×10⁻⁶. 6 cfu / mL; the inoculation volume of the bacterial suspension in step S3 is 6.5 vol.%; the inoculation volume of the liquid seed solution in step S4 is 13 vol.%; the culture conditions for solid culture in step S4 are: temperature 20℃, relative humidity 65%, light intensity 1800 lux, photoperiod 12h light / 12h dark, 2 hours of blue light irradiation per day, culture for 60 days; the maturity of the Cordyceps militaris fruiting body in step S5 is when its stroma length is more than 8 cm.

[0035] Example 4 A method for cultivating strontium-enriched Cordyceps militaris includes the following steps: Step S1: Preparation of culture medium: Dissolve each component in pure water according to the liquid seed culture medium formula, mix evenly, pour into culture flasks, seal, sterilize, and cool to obtain liquid seed culture medium; prepare solid culture medium according to the solid culture medium formula. Step S2, strain activation: Inoculate the Cordyceps militaris strain onto PDA slant medium and incubate at 21.5℃ for 9.5 days. After the mycelium has covered the slant, rinse with sterile physiological saline to obtain a bacterial suspension. Step S3, Liquid seed culture: Inoculate the bacterial suspension into the liquid seed culture medium, place it in a shaker, and culture at 21.5℃ and 175r / min for 4.5 days to obtain the liquid seed culture; Step S4, Solid Culture: Spray the liquid seed solution evenly onto the surface of the solid culture medium and place it in an incubator for solid culture; Step S5, Harvesting and Drying: After the fruiting bodies of Cordyceps militaris mature, harvest the fruiting bodies and mycelium, rinse with clean water to remove surface impurities, vacuum dry at 65℃ to constant weight, pulverize and pass through a 95-mesh sieve to obtain strontium-rich Cordyceps militaris product.

[0036] The liquid seed culture medium in step S1 consists of the following components in the following proportions: glucose 24 g / L, peptone 11.5 g / L, yeast extract 4.5 g / L, strontium nitrate 0.75 g / L, strontium citrate 0.45 g / L, compound nutrients 0.75 g / L, vitamin B1 0.09 g / L, vitamin B6 0.045 g / L, calcium carbonate 1 g / L, ferrous sulfate 0.11 g / L, silkworm pupa polypeptide powder 7.5 g / L, L-proline 0.18 g / L, and fructooligosaccharides 7.5 g / L, with the pH adjusted to 6.3; the compound nutrients consist of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:2:1.

[0037] The solid culture medium in step S1 consists of the following components in the following proportions: 68 parts wheat grains, 19 parts silkworm pupa powder, 7.5 parts corn flour, 4.5 parts glucose, 0.75 parts strontium chloride, 0.45 parts strontium citrate, 0.45 parts compound synergist, 48 parts rice flour, 18 parts barley sprout powder, 7.5 parts plant polysaccharides, and 145 parts water, adjusted to pH 6.1; the compound synergist is composed of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:3:1; the plant polysaccharides are a mixture of tea polysaccharides, wolfberry polysaccharides, and shiitake mushroom polysaccharides in a mass ratio of 1:2:1; the sterilization temperature in step S1 is 121℃, and the time is 30 min; the Cordyceps militaris strain in step S2 is ACCC50632; the bacterial concentration in the bacterial suspension in step S2 is 4.5 × 10⁻⁶. 6 cfu / mL; the inoculation amount of the bacterial suspension in step S3 is 7.5 vol.%; the inoculation amount of the liquid seed solution in step S4 is 14 vol.%; the culture conditions for solid culture in step S4 are: temperature 21℃, relative humidity 68%, light intensity 1900 lux, photoperiod 12h light / 12h dark, 2 hours of blue light irradiation per day, culture for 63 days; the maturity of the Cordyceps militaris fruiting body in step S5 is when its stroma length is more than 8 cm.

[0038] Example 5 A method for cultivating strontium-enriched Cordyceps militaris includes the following steps: Step S1: Preparation of culture medium: Dissolve each component in pure water according to the liquid seed culture medium formula, mix evenly, pour into culture flasks, seal, sterilize, and cool to obtain liquid seed culture medium; prepare solid culture medium according to the solid culture medium formula. Step S2, strain activation: Take Cordyceps militaris strain and inoculate it into PDA slant medium. Incubate at 22℃ for 10 days. After the mycelium has covered the slant, wash with sterile physiological saline to obtain a bacterial suspension. Step S3, Liquid seed culture: Inoculate the bacterial suspension into liquid seed culture medium, place it in a shaker, and culture at 22℃ and 180r / min for 5 days to obtain liquid seed culture; Step S4, Solid Culture: Spray the liquid seed solution evenly onto the surface of the solid culture medium and place it in an incubator for solid culture; Step S5, Harvesting and Drying: After the fruiting bodies of Cordyceps militaris mature, harvest the fruiting bodies and mycelium, rinse with clean water to remove surface impurities, vacuum dry at 65℃ to constant weight, pulverize and pass through a 100-mesh sieve to obtain strontium-rich Cordyceps militaris product.

[0039] The liquid seed culture medium described in step S1 consists of the following components in the following proportions: glucose 25 g / L, peptone 12 g / L, yeast extract 5 g / L, strontium nitrate 0.8 g / L, strontium citrate 0.5 g / L, compound nutrients 0.8 g / L, vitamin B1 0.1 g / L, vitamin B6 0.05 g / L, calcium carbonate 1.2 g / L, ferrous sulfate 0.12 g / L, silkworm pupa polypeptide powder 8 g / L, L-proline 0.2 g / L, and fructooligosaccharides 8 g / L, with the pH adjusted to 6.5; the compound nutrients consist of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:2:1.

[0040] The solid culture medium in step S1 consists of the following components in the following proportions: 70 parts wheat grains, 20 parts silkworm pupa powder, 8 parts corn flour, 5 parts glucose, 0.8 parts strontium chloride, 0.5 parts strontium citrate, 0.5 parts compound synergist, 50 parts rice flour, 20 parts barley sprout powder, 8 parts plant polysaccharide, and 150 parts water, adjusted to pH 6.2; the compound synergist is composed of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:3:1; the plant polysaccharide is tea polysaccharide; the sterilization temperature in step S1 is 121℃, and the time is 30 min; the Cordyceps militaris strain in step S2 is ACCC50632; the bacterial concentration in the bacterial suspension in step S2 is 5 × 10⁻⁶. 6cfu / mL; the inoculation volume of the bacterial suspension in step S3 is 8 vol.%; the inoculation volume of the liquid seed solution in step S4 is 15 vol.%; the culture conditions for solid culture in step S4 are: temperature 22℃, relative humidity 70%, light intensity 2000 lux, photoperiod 12h light / 12h dark, 2 hours of blue light irradiation per day, culture for 65 days; the maturity of the Cordyceps militaris fruiting body in step S5 is when its stroma length is more than 8 cm.

[0041] Comparative Example 1 A method for cultivating strontium-rich Cordyceps militaris is basically the same as in Example 1, except that strontium nitrate is used instead of strontium citrate in the liquid seed culture medium.

[0042] Comparative Example 2 A method for cultivating strontium-rich Cordyceps militaris is basically the same as in Example 1, except that barley grass powder and plant polysaccharides are not added.

[0043] To further illustrate the beneficial technical effects of the strontium-rich Cordyceps militaris cultivation methods involved in the various embodiments of the present invention, relevant performance tests were conducted on the products of Example 1 and Comparative Examples 1-2. The test results are shown in Table 1, and the test methods are as follows: (1) Strontium content detection: Strontium content was detected according to the first method of GB 5009.268-2016; (2) Cordycepin and adenosine detection: The material was detected by HPLC. The detection conditions were: ZORBAX SB-C18 column (4.6 mm × 250 mm, 5 μm), mobile phase methanol-water (22:78, v / v), flow rate 1.0 mL / min, detection wavelength 260 nm, column temperature 35 ℃, injection volume 20 μL, and external standard method for quantification. (3) Biomass detection: After harvesting, vacuum dry (65℃, -0.09MPa) to constant weight, and weigh the dry weight using an electronic balance (accuracy 0.001g).

[0044] As shown in Table 1, the strontium-enriched Cordyceps militaris cultivated in the embodiments of the present invention has higher strontium content, cordycepin content, adenosine content and biomass than the comparative product; the combined use of strontium citrate, barley grass powder and plant polysaccharides has a synergistic effect that is more conducive to the enrichment of strontium, synthesis of active ingredients and biomass accumulation of strontium-enriched Cordyceps militaris.

[0045] Table 1. Performance test results of strontium-enriched Cordyceps militaris Item Example 1 Comparative Example 1 Comparative Example 2 Strontium content (mg / kg) 14.9 10.4 9.8 Cordycepin (g / 100g) 0.27 0.20 0.14 Adenosine (mg / 100g) 27.3 21.8 15.6 Biomass (g / plant) 1.23 1.06 0.81 The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for cultivating strontium-enriched Cordyceps militaris, characterized in that, Includes the following steps: Step S1: Preparation of culture medium: Dissolve each component in pure water according to the liquid seed culture medium formula, mix evenly, pour into culture flasks, seal, sterilize, and cool to obtain liquid seed culture medium; prepare solid culture medium according to the solid culture medium formula. Step S2, strain activation: Take Cordyceps militaris strain and inoculate it on PDA slant medium. Incubate at 20-22℃ for 7-10 days. After the mycelium has covered the slant, wash it with sterile physiological saline to obtain a bacterial suspension. Step S3, Liquid seed culture: Inoculate the bacterial suspension into the liquid seed culture medium, place it in a shaker, and culture at 20-22℃ and 150-180 r / min for 3-5 days to obtain the liquid seed culture; Step S4, Solid Culture: Spray the liquid seed solution evenly onto the surface of the solid culture medium and place it in an incubator for solid culture; Step S5, Harvesting and Drying: After the fruiting bodies of Cordyceps militaris mature, harvest the fruiting bodies and mycelium, rinse with clean water to remove surface impurities, vacuum dry at 55-65℃ to constant weight, and pulverize through an 80-100 mesh sieve to obtain strontium-rich Cordyceps militaris product.

2. The method for cultivating strontium-enriched Cordyceps militaris according to claim 1, characterized in that, The liquid seed culture medium described in step S1 consists of the following components in the following proportions: glucose 20-25 g / L, peptone 10-12 g / L, yeast extract 3-5 g / L, strontium nitrate 0.5-0.8 g / L, strontium citrate 0.3-0.5 g / L, compound nutrients 0.5-0.8 g / L, vitamin B1 0.05-0.1 g / L, vitamin B6 0.03-0.05 g / L, calcium carbonate 0.6-1.2 g / L, ferrous sulfate 0.07-0.12 g / L, silkworm pupa polypeptide powder 6-8 g / L, L-proline 0.1-0.2 g / L, and fructooligosaccharides 5-8 g / L, with the pH adjusted to 5.5-6.

5.

3. The method for cultivating strontium-enriched Cordyceps militaris according to claim 2, characterized in that, The compound nutrients consist of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:2:

1.

4. The method for cultivating strontium-enriched Cordyceps militaris according to claim 1, characterized in that, The solid culture medium described in step S1 consists of the following components in the following proportions: 60-70 parts wheat grains, 15-20 parts silkworm pupa powder, 5-8 parts corn flour, 3-5 parts glucose, 0.5-0.8 parts strontium chloride, 0.3-0.5 parts strontium citrate, 0.3-0.5 parts compound synergist, 40-50 parts rice flour, 10-20 parts barley grass powder, 5-8 parts plant polysaccharides, and 120-150 parts water, with the pH adjusted to 5.8-6.

2.

5. The method for cultivating strontium-enriched Cordyceps militaris according to claim 4, characterized in that, The composite synergist is composed of magnesium sulfate, zinc sulfate, and selenomethionine in a mass ratio of 5:3:

1.

6. The method for cultivating strontium-enriched Cordyceps militaris according to claim 4, characterized in that, The plant polysaccharide is at least one of tea polysaccharide, wolfberry polysaccharide, and shiitake mushroom polysaccharide.

7. The method for cultivating strontium-enriched Cordyceps militaris according to claim 1, characterized in that, The sterilization temperature in step S1 is 121℃, and the time is 30 min; the Cordyceps militaris strain in step S2 is ACCC50632; the bacterial concentration in the bacterial suspension in step S2 is 1×10⁻⁶. 6 -5×10 6 cfu / mL.

8. The method for cultivating strontium-enriched Cordyceps militaris according to claim 1, characterized in that, The inoculation volume of the bacterial suspension in step S3 is 5-8 vol.%; the inoculation volume of the liquid seed solution in step S4 is 10-15 vol.%.

9. The method for cultivating strontium-enriched Cordyceps militaris according to claim 1, characterized in that, The solid-state culture conditions described in step S4 are: temperature 18-22℃, relative humidity 60-70%, light intensity 1500-2000 lux, light cycle 12h light / 12h dark, 2 hours of blue light irradiation per day, and culture for 55-65 days.

10. The method for cultivating strontium-enriched Cordyceps militaris according to claim 1, characterized in that, The maturation of the Cordyceps militaris fruiting body in step S5 is defined as a stroma length of 8 cm or more.