A fermentation process for edible fungi secreting and expressing chitin

Abstract

The present invention discloses a fermentation process of edible fungi that secrete and express chitin production and its application. The edible fungi strains are cultured and purified, and mycelium is prepared by inoculation, and then demoulding, drying and inactivation are performed to obtain a straw mycelium material. The present invention optimizes the fermentation process of edible fungi that secrete and express chitin production to obtain a large amount of mycelium, and the straw is fixed and wrapped by the mycelium to obtain a straw mycelium material with good adhesion, stable performance and not easy to break. The present invention uses straw powder as a chitin inducer, which effectively increases the chitin content in the seed liquid, and effectively improves the firmness and stability of the material.

Description

Technical Field

[0001] The invention belongs to the field of bioengineering, and in particular relates to an edible fungus fermentation process for secreting and expressing chitin. Background Art

[0002] At present, traditional petroleum-based polymer materials release toxic substances and greenhouse gases during disposal. Plastics cannot be degraded within a reasonable time frame, causing serious pollution to the environment and ecosystem. my country's plastic production has reached more than 60 million tons, of which 2.4 million tons are foam plastics, a large part of which is used as packaging materials. Therefore, people's demand for "green" materials and production processes is growing.

[0003] At present, the mainstream biodegradable plastics mainly include polymer materials directly produced by biotechnology, such as polyhydroxyalkanoates (PHA); polymer materials obtained by polymerizing biological raw materials, such as polylactic acid (PLA), polybutylene succinate (PBS); in addition, there are starch-based biodegradable plastics, carbon dioxide copolymerized aliphatic plastics (PPC), etc. However, compared with traditional plastics, biodegradable plastics usually have poor mechanical properties, are not resistant to high temperatures, and have generally high production costs and prices. After some blended materials are degraded, plastic particles remain for a long time, and food-based materials have the problem of "competing with people for food." Finding new biodegradable, safe, and low-cost biodegradable plastic products has always been a hot topic and focus of research.

[0004] Therefore, the development of green cushioning packaging materials with good environmental compatibility has become the mainstream of sustainable development of packaging in the world. At present, there is a kind of cushioning packaging material that uses crops as raw materials, inoculates fungal species, utilizes the growth characteristics of mycelium, and forms a loose and porous cushioning structure through mycelium connection to make a green and environmentally friendly degradable cushioning packaging material. At present, the existing technology only discloses the formation principle and production process of the material, but due to the shortcomings in its raw material composition and preparation method, the cushioning packaging material prepared based on the existing published technology has a low amount of mycelium inside the material and poor adhesion, resulting in poor static cushioning performance and easy breakage of the material, and cannot be used as a cushioning packaging material. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a fermentation process of edible fungi for secreting and expressing chitin in view of the deficiencies of the prior art.

[0006] The technical problem that the present invention also aims to solve is to use the above-mentioned edible fungus fermentation process in the preparation of cushioning packaging materials.

[0007] In order to solve the above technical problems, the present invention discloses a fermentation process for edible fungi that secretes and expresses chitin, wherein the edible fungi strains are inoculated into seed liquid for cultivation, and then the edible fungi seed liquid is inoculated into a solid matrix, stirred evenly, and sealed for solid-state fermentation to prepare mycelium.

[0008] The seed liquid contains inducer straw powder, and the inducer straw powder is any one or a combination of corn straw powder, wheat straw powder, rice straw powder, reed straw powder, and sorghum straw powder, preferably corn straw powder.

[0009] Specifically, since the strain needs to capture polysaccharides for metabolic utilization through the end of mycelium during its growth, and compared to the easy utilization of glucose or other pure polysaccharides, the utilization of the fiber polysaccharides in the straw requires the mycelium to penetrate into the interior of the straw to digest and absorb this part of the sugar source. This process will stimulate the cell wall to increase the concentration of rigid chitin, so straw powder can be used as an inducer to induce high secretion of chitin.

[0010] The solid matrix comprises the following components in weight percentage: 20-80% straw, 20%-80% sawdust, 5%-25% bran, preferably 40% corn straw, 40% sawdust, and 20% bran.

[0011] The edible fungus strains are cultured and purified in advance, and the method is: the edible fungus slices are inoculated into a solid plate culture medium and cultured at 25°C, after the mycelium grows all over the plate, the mycelium without foreign bacteria is picked and transferred into the seed liquid and cultured at 25°C and 170rpm until the biomass of the bacterial liquid is greater than 15g / L, and then transferred into a new solid plate culture medium for streaking culture. A single colony is picked and continued to be cultured in a new solid plate culture medium to obtain a purified edible fungus strain.

[0012] Specifically, the edible fungi are any one or a combination of Pleurotus ostreatus, Volvariella volvacea, Agrocybe tumefaciens, Flammulina velutipes, Pleurotus eryngii, Hericium erinaceus, Morchella oleracea, and Ganoderma lucidum, preferably Ganoderma lucidum, and most preferably Taishan Ganoderma lucidum.

[0013] Specifically, the solid plate culture medium has the following formula: glucose (basic carbon source) 20 g / L, potassium dihydrogen sulfate 3 g / L, magnesium sulfate heptahydrate 1.5 g / L, vitamin B1 0.1 g / L, agar 15 g / L, yeast powder (basic nitrogen source) 7.6 g / L.

[0014] Specifically, the seed solution has the following formula: nitrogen source 0.9-1.1 g / L, carbon source 21-25 g / L, straw powder 1-5 g / L (inducer), MgSO4 0.4 g / L, FeSO4·7H2O 0.1 g / L, KH2PO4 0.1 g / L, VB1 0.01 g / L. The preferred carbon source content is 25 g / L, the nitrogen source content is 1.1 g / L, and the straw powder content is 1.5 g / L.

[0015] Specifically, the carbon source of the seed liquid is any one or a combination of glucose, hemicellulose, corn starch and commercial pulp, preferably corn starch.

[0016] Specifically, the nitrogen source of the seed liquid is any one or a combination of yeast powder, yeast extract, amino acid fermentation waste liquid and corn steep liquor, preferably amino acid fermentation waste liquid.

[0017] Specifically, the straw powder particle size of the seed liquid includes any one of 12 mesh, 60 mesh, 150 mesh and 200 mesh, preferably 150 mesh.

[0018] Specifically, the chitin content of the seed solution is analyzed by infrared semi-quantitative analysis based on 1371cm -1 The height of the chitin absorption peak is used to compare the chitin content concentration (reference Haneef M, Ceseracciu L, Canale C, et al. Advanced Materials From Fungal Mycelium: Fabrication and Tuning of Physical Properties [J]. Rep, 2017, 7: 41292.). When the absorption peak is high, it means that the chitin content concentration is high; when the absorption peak is low, it means that the chitin content concentration is low.

[0019] Specifically, the edible fungus strains are inoculated into the seed liquid at 25-28°C, cultured at 170rpm for 5-10 days, and then the edible fungus seed liquid is inoculated into the solid matrix at a volume ratio of 16%-23%, filled into the mold, and the mold is sealed and placed on a shaker for static culture to perform solid-state fermentation to prepare mycelium, the solid-state fermentation temperature is 25-32°C, and the solid-state fermentation time is 5-10 days. The preferred seed liquid culture temperature is 25°C, the culture time is 7 days, the preferred edible fungus seed liquid is inoculated into the solid matrix at a volume ratio of 20%, the preferred solid-state fermentation temperature is 25°C, and the fermentation time is 7 days.

[0020] The prepared mycelium is demoulded, dried and inactivated to obtain a straw mycelium material with a material density of 0.181-0.201 g / cm 3, the compression strength is 0.32-0.45MPa. The preferred material density is 0.183g / cm 3 , the compression strength is 0.45MPa.

[0021] Specifically, after solid-state fermentation is completed, the material that has been shaped and covered with white mycelium on the surface is removed from the mold, and the material is placed in a 70° C. oven for drying and dehydration for 20 hours to inactivate the bacteria inside the matrix and stop its growth, thereby obtaining a straw mycelium material.

[0022] Specifically, the obtained straw mycelium material is subjected to mechanical property and density testing: the mechanical property testing equipment is a universal testing machine, the tested performance is compression strength, and the testing standard refers to the national standard "GB / T 8813-2020"; the density test refers to the national standard "GB / T 6343-2009".

[0023] The straw mycelium material prepared by the fermentation process of edible fungi that secrete and express chitin is also within the protection scope of the present invention.

[0024] The application of the straw mycelium material in the preparation of cushioning packaging materials is also within the protection scope of the present invention.

[0025] Beneficial effects:

[0026] (1) The mechanical properties of the material are directly determined by the amount of mycelium. The more mycelium on the surface, the stronger the material. The present invention optimizes the fermentation process of edible fungi that secrete and express chitin production, so that the amount of mycelium enriched on the surface of the solid matrix is ​​higher than that of the ordinary fermentation process. The mycelium is used to fix and wrap the straw, thereby obtaining a straw mycelium material with good adhesion, stable performance, and not easy to break.

[0027] (2) Chitin determines the mechanical properties of straw mycelium materials. The present invention uses straw powder as a chitin inducer, which effectively increases the chitin content in the seed liquid, thereby effectively improving the firmness and stability of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0029] Figure 1 Comparison of straw mycelium materials with almost no mycelium on the surface (left) and those with mycelium growing all over the surface (right)

[0030] Figure 2 These are SEM images of the internal matrix of straw mycelium materials with the optimal carbon and nitrogen source formula (2A) and the common carbon and nitrogen source formula (2B).

[0031] Figure 3This is an infrared comparison of the bacterial balls in the seed liquid when no corn straw powder is added and corn straw powder with different particle sizes is added as chitin inducer in the seed liquid culture medium (red means the added inducer is corn straw powder with the optimal particle size of 150 mesh, green means the added inducer is corn straw powder with a particle size of 60 mesh, and blue means no inducer is corn straw powder). DETAILED DESCRIPTION

[0032] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0033] In the following examples, the strain materials used, including Taishan Ganoderma lucidum, Pleurotus ostreatus grass scraps 28, Flammulina velutipes F3, and Volvariella volvacea V901, were purchased from Tianda Edible Fungi Research Institute.

[0034] Example 1: Fermentation process and application of Taishan Ganoderma lucidum (Ganoderma lucidum) for secretory expression of chitin

[0035] Inoculate Taishan Ganoderma lucidum slices into solid plate culture medium at 25°C under a clean bench. After the mycelium has grown all over the plate, pick the mycelium without foreign bacteria and transfer it into the seed liquid culture medium at 25°C and 170rpm to continue culturing until the bacterial liquid is thick, and then transfer it to a new plate for streaking culture. Pick a single colony and continue culturing it in a new plate to obtain the purified Taishan Ganoderma lucidum strain.

[0036] The Taishan Ganoderma lucidum strains were inoculated into the seed liquid culture medium and cultured at 25°C and 170rpm for about 7 days. In the clean bench, the seed liquid obtained after the above culture was inoculated into the solid matrix according to 20% of the volume of the solid matrix (sterilized before inoculation: 121°C, 15min), stirred evenly and filled into the mold, the mold was sealed and placed in a 25°C shaker for static culture for 7 days, and the mycelium material was prepared by solid fermentation.

[0037] The solid plate culture medium has the following formula: glucose (basic carbon source) 20 g / L, potassium dihydrogen sulfate 3 g / L, magnesium sulfate heptahydrate 1.5 g / L, vitamin B1 0.1 g / L, agar 15 g / L, yeast powder (basic nitrogen source) 7.6 g / L.

[0038] The seed liquid culture medium has the following formula: nitrogen source 1.1 g / L, carbon source 25 g / L, corn straw powder 1.5 g / L (inducer), MgSO4 0.4 g / L, FeSO4·7H2O 0.1 g / L, KH2PO4 0.1 g / L, VB1 0.01 g / L. The nitrogen source is amino acid fermentation waste liquid, the carbon source is corn starch, and the straw powder particle size is 150 mesh.

[0039] The solid matrix includes the following components in weight percentage: 40% corn stalks, 40% sawdust and 20% bran.

[0040] After solid-state fermentation is completed, the straw mycelium material (such as Figure 1 As shown), the material was placed in a 70°C oven for drying and dehydration for 20 hours, thereby inactivating the bacteria inside the matrix and stopping their growth.

[0041] The material after treatment is tested for performance. The mechanical performance testing equipment is a universal testing machine. The tested performance is compressive strength. The testing standard refers to the national standard "GB / T 8813-2020"; the density test refers to the national standard "GB / T 6343-2009". Performance test results: Apparent density: 0.183g / cm 3 ; Compression strength: 0.45MPa.

[0042] Example 2: Fermentation process and application of Pleurotus ostreatus grass scraps 28 for secretory expression of chitin

[0043] Inoculate the slices of Pleurotus ostreatus grass scraps 28 into a solid plate medium and culture at 25°C under a clean bench. After the mycelium has grown all over the plate, pick the mycelium without foreign bacteria and transfer it into the seed liquid medium and continue to culture at 25°C and 170rpm until the bacterial liquid is thick, and then transfer it to a new plate for streaking culture. Pick a single colony and continue to culture it in a new plate to obtain the pure Pleurotus ostreatus grass scraps 28 strain.

[0044] Inoculate the 28 strains of Pleurotus ostreatus grass clippings into the seed liquid culture medium and culture at 25°C and 170rpm for about 5 days. In a clean bench, inoculate the seed liquid obtained after the above culture into the solid matrix according to 20% of the volume of the solid matrix (sterilized before inoculation: 121°C, 15min), stir evenly and fill into the mold, seal the mold and place it in a shaker at 25°C for static culture for 5 days to perform solid fermentation to prepare mycelium material.

[0045] The solid plate culture medium has the following formula: glucose (basic carbon source) 20 g / L, potassium dihydrogen sulfate 3 g / L, magnesium sulfate heptahydrate 1.5 g / L, vitamin B1 0.1 g / L, agar 15 g / L, yeast powder (basic nitrogen source) 7.6 g / L.

[0046] The seed liquid culture medium has the following formula: nitrogen source 0.9g / L, carbon source 21g / L, corn straw powder 1.5g / L (inducer), MgSO4 0.4g / L, FeSO4·7H2O 0.1g / L, KH2PO4 0.1g / L, VB1 0.01g / L. The nitrogen source is amino acid fermentation waste liquid, the carbon source is corn starch, and the straw powder particle size is 150 mesh.

[0047] The solid matrix includes the following components in weight percentage: 40% corn stalks, 40% sawdust and 20% bran.

[0048] After solid-state fermentation, the straw mycelium material that has been shaped and covered with white mycelium on the surface is removed from the mold and placed in a 70°C oven for drying and dehydration for 20 hours, thereby inactivating the bacteria inside the matrix and stopping their growth.

[0049] The material after treatment is tested for performance. The mechanical performance testing equipment is a universal testing machine. The tested performance is compression strength. The testing standard refers to the national standard "GB / T 8813-2020"; the density test refers to the national standard "GB / T 6343-2009". Performance test results: Apparent density: 0.191g / cm 3 ; Compression strength: 0.43MPa (25% deformation).

[0050] Example 3: Fermentation process and application of secretory expression of chitin-producing Volvariella volvacea V901

[0051] Inoculate slices of Volvariella V901 into solid plate culture medium at 25°C under a clean bench. After the mycelium has grown all over the plate, pick the mycelium without foreign bacteria and transfer it into the seed liquid culture medium at 25°C and 170rpm to continue culturing until the bacterial liquid is thick, and then transfer it to a new plate for streaking culture. Pick a single colony and continue culturing it in a new plate to obtain the pure Volvariella V901 strain.

[0052] The V901 strain of Volvariella volvacea was inoculated into the seed liquid culture medium and cultured at 25°C and 170 rpm for about 7 days. In a clean bench, the seed liquid obtained after the above culture was inoculated into the solid matrix according to 20% of the volume of the solid matrix (sterilized before inoculation: 121°C, 15 minutes), stirred evenly and filled into the mold, the mold was sealed and placed in a shaking table at 25°C for static culture for 7 days to perform solid fermentation to prepare mycelium material.

[0053] The solid plate culture medium has the following formula: glucose (basic carbon source) 20 g / L, potassium dihydrogen sulfate 3 g / L, magnesium sulfate heptahydrate 1.5 g / L, vitamin B1 0.1 g / L, agar 15 g / L, yeast powder (basic nitrogen source) 7.6 g / L.

[0054] The seed liquid culture medium has the following formula: nitrogen source 0.9g / L, carbon source 21g / L, corn straw powder 1.5g / L (inducer), MgSO4 0.4g / L, FeSO4·7H2O 0.1g / L, KH2PO4 0.1g / L, VB1 0.01g / L. The nitrogen source is amino acid fermentation waste liquid, the carbon source is corn starch, and the straw powder particle size is 150 mesh.

[0055] The solid matrix includes the following components in weight percentage: 40% corn stalks, 40% sawdust and 20% bran.

[0056] After solid-state fermentation is completed, the straw mycelium material (such as Figure 1 As shown), the material was placed in a 70°C oven for drying and dehydration for 20 hours, thereby inactivating the bacteria inside the matrix and stopping their growth.

[0057] The material after treatment is tested for performance. The mechanical performance testing equipment is a universal testing machine. The tested performance is compressive strength. The testing standard refers to the national standard "GB / T 8813-2020"; the density test refers to the national standard "GB / T 6343-2009". Performance test results: Apparent density: 0.189g / cm 3 ; Compression strength: 0.43MPa (25% deformation).

[0058] Example 4: Fermentation process and application of Flammulina velutipes F3 expressing chitin

[0059] Inoculate the slices of Flammulina velutipes F3 into a solid plate medium under a clean bench and culture at 25°C. After the mycelium has grown all over the plate, pick the mycelium without foreign bacteria and transfer it into the seed liquid medium and continue to culture at 25°C and 170rpm until the bacterial liquid is thick, and then transfer it to a new plate for streak culture. Pick a single colony and continue to culture it in a new plate to obtain the pure Flammulina velutipes F3 strain.

[0060] The Flammulina velutipes F3 strain was inoculated into the seed liquid culture medium and cultured at 28°C and 170 rpm for about 10 days. In a clean bench, the seed liquid obtained after the above culture was inoculated into the solid matrix according to 20% of the volume of the solid matrix (sterilized before inoculation: 121°C, 15 minutes), stirred evenly and filled into the mold, the mold was sealed and placed in a shaking incubator at 25°C for static culture for 10 days to perform solid fermentation to prepare the mycelium material.

[0061] The solid plate culture medium has the following formula: glucose (basic carbon source) 20 g / L, potassium dihydrogen sulfate 3 g / L, magnesium sulfate heptahydrate 1.5 g / L, vitamin B1 0.1 g / L, agar 15 g / L, yeast powder (basic nitrogen source) 7.6 g / L.

[0062] The seed liquid culture medium has the following formula: nitrogen source 0.9g / L, carbon source 21g / L, corn straw powder 1.5g / L (inducer), MgSO4 0.4g / L, FeSO4·7H2O 0.1g / L, KH2PO4 0.1g / L, VB1 0.01g / L. The nitrogen source is amino acid fermentation waste liquid, the carbon source is corn starch, and the straw powder particle size is 150 mesh.

[0063] The solid matrix includes the following components in weight percentage: 40% corn stalks, 40% sawdust and 20% bran.

[0064] After solid-state fermentation, the straw mycelium material that has been shaped and covered with white mycelium on the surface is removed from the mold and placed in a 70°C oven for drying and dehydration for 20 hours, thereby inactivating the bacteria inside the matrix and stopping their growth.

[0065] The material after treatment is tested for performance. The mechanical performance testing equipment is a universal testing machine. The tested performance is compression strength. The testing standard refers to the national standard "GB / T 8813-2020"; the density test refers to the national standard "GB / T 6343-2009". Performance test results: Apparent density: 0.2g / cm 3 ; Compression strength: 0.41MPa (25% deformation).

[0066] Example 5: Fermentation process of Taishan Ganoderma lucidum for secretory expression of chitin and its application (common carbon and nitrogen source combination)

[0067] Compared with Example 1, the carbon and nitrogen source formula was changed to nitrogen source type: yeast extract; carbon source type: glucose, and other conditions remained unchanged.

[0068] The material after treatment is tested for performance. The mechanical performance testing equipment is a universal testing machine. The tested performance is compression strength. The testing standard refers to the national standard "GB / T 8813-2020"; the density test refers to the national standard "GB / T6343-2009". Performance test results: Apparent density: 0.191g / cm 3 ; Compression strength: 0.32MPa.

[0069] The matrix inside the material was subjected to SEM analysis and compared with Example 1. Figure 2 As shown, the surface of the solid matrix in the left picture is wrapped with densely grown mycelium (similar to spider silk wrapped around solid matrices such as straw), while the mycelium on the surface of the right picture is relatively sparse due to the failure to use the optimal formula. Therefore, the high-content mycelium material in the left picture exhibits higher mechanical properties.

[0070] Example 6 Fermentation process of Taishan Ganoderma lucidum for secretory expression of chitin and its application (changing the type of carbon source)

[0071] The preparation process was the same as in Example 1, except that the type of carbon source in the seed solution was changed and other conditions remained unchanged. The performance test results are shown in Table 1 below.

[0072] Table 1 Material performance test results under different carbon source types

[0073]

[0074]

[0075] Example 7 Fermentation process of Taishan Ganoderma lucidum for secretory expression of chitin and its application (changing the type of nitrogen source)

[0076] The preparation process was the same as in Example 1, except that the type of nitrogen source in the seed solution was changed and other conditions remained unchanged. The performance test results are shown in Table 2 below.

[0077] Table 2 Material performance test results under different nitrogen sources

[0078] Nitrogen source Material density Compression performance Yeast powder <![CDATA[0.197g / cm 3 ]]> 0.34MPa Yeast extract <![CDATA[0.188g / cm 3 ]]> 0.34MPa Amino acid fermentation wastewater <![CDATA[0.183g / cm 3 ]]> 0.45MPa Corn Syrup <![CDATA[0.193g / cm 3 ]]> 0.38MPa

[0079] Example 8 Fermentation process of Taishan Ganoderma lucidum for secretory expression of chitin and its application (changing the particle size of straw powder)

[0080] The preparation process was the same as in Example 1, except that the particle size of the corn stalk powder in the seed solution was changed, and other conditions remained unchanged. The performance test results are shown in Table 3 below.

[0081] Corn stalk powder particle size Material density Compression performance 12 mesh <![CDATA[0.196g / cm 3 ]]> 0.33MPa 60 mesh <![CDATA[0.194g / cm 3 ]]> 0.41MPa 150 mesh <![CDATA[0.183g / cm 3 ]]> 0.45MPa 200 mesh <![CDATA[0.181g / cm 3 ]]> 0.44MPa

[0082] Example 9 No inducer example (compared with Example 1)

[0083] The preparation process is the same as in Example 1, except that the inducer straw powder is not added, and other conditions remain unchanged. The material after treatment is subjected to performance testing. The mechanical performance testing equipment is a universal testing machine. The performance tested is compression strength. The testing standard refers to the national standard "GB / T 8813-2020"; the density test refers to the national standard "GB / T 6343-2009". Performance test results: Apparent density: 0.185g / cm 3 ; Compression strength: 0.28MPa.

[0084] like Figure 3 The following is an infrared comparison of the bacterial balls in the seed liquid culture medium when no corn stalk powder is added and corn stalk powder of different particle sizes is added as chitin inducer. The red part is the corn stalk powder with the optimal particle size of 150 mesh added as inducer, the green part is the corn stalk powder with the particle size of 60 mesh added as inducer, and the blue part is the corn stalk powder without the addition of inducer. The 1371cm -1 From the chitin absorption peak, it can be seen that the green and red absorption peaks are significantly higher than the blue absorption peak.

[0085] The present invention provides a fermentation process of edible fungi that secretes and expresses chitin and a method and idea for its application in materials. There are many methods and approaches to specifically implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be considered as the scope of protection of the present invention. All components not specified in this embodiment can be implemented using existing technologies.

Claims

1. A fermentation process for edible fungi to secrete and express chitin, characterized in that: After the edible fungus strains are inoculated into the seed liquid for cultivation, the edible fungus seed liquid is then inoculated into the solid matrix, stirred evenly, and sealed for solid-state fermentation to prepare mycelium; Wherein, the seed liquid contains the inducer straw powder, and the inducer straw powder is corn straw powder, and the content of the corn straw powder is 1-5 g / L; The solid matrix comprises the following components in weight percentage: 20% to 80% straw, 20% to 80% sawdust, and 5% to 25% bran.

2. The edible fungus fermentation process for secreting and expressing chitin according to claim 1, characterized in that: The edible fungi are pre-purified by the following purification method: slice the edible fungi and inoculate them into a solid plate culture medium for culturing, pick out mycelium without foreign bacteria and transfer them into seed liquid for continuous culturing until the biomass of the bacterial liquid is greater than 15g / L, and then transfer them into a new solid plate culture medium for streaking culturing to obtain purified edible fungi strains.

3. The edible fungus fermentation process for secreting and expressing chitin according to claim 2, characterized in that: The edible fungi are any one or a combination of the following: oyster mushroom, straw mushroom, tea tree mushroom, enoki mushroom, king oyster mushroom, hericium erinaceus, morel mushroom and ganoderma lucidum.

4. The edible fungus fermentation process for secreting and expressing chitin according to claim 1 or 2, characterized in that: The carbon source of the seed liquid is any one or a combination of glucose, hemicellulose, corn starch and commercial pulp, and the carbon source content is 21-25 g / L.

5. The edible fungus fermentation process for secreting and expressing chitin according to claim 1 or 2, characterized in that: The nitrogen source of the seed liquid is any one or a combination of yeast powder, yeast extract, amino acid fermentation waste liquid and corn steep liquor, and the nitrogen source content is 0.9-1.1 g / L.

6. The edible fungus fermentation process for secreting and expressing chitin according to claim 1 or 2, characterized in that: The straw powder particle size of the seed liquid includes any one of 12 meshes, 60 meshes, 150 meshes and 200 meshes.

7. The edible fungus fermentation process for secreting and expressing chitin according to claim 1, characterized in that: The edible fungus strains were inoculated into the seed liquid at 25-28°C and 170 rpm for 5-10 days, and then the edible fungus seed liquid was inoculated into the solid matrix at a volume ratio of 16%-23%, stirred evenly, and sealed for solid-state fermentation. The solid-state fermentation temperature was 25-32°C and the solid-state fermentation time was 5-10 days.

8. The edible fungus fermentation process for secreting and expressing chitin according to claim 1, characterized in that: The prepared mycelium was demoulded, dried and inactivated to obtain straw mycelium material, the material density of which was 0.181-0.201 g / cm 3 , the compression strength is 0.32 -0.45 MPa.

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