Mycelium mineral compounded bionic sand stabilization unit body and preparation method thereof

Abstract

The invention discloses a hypha mineral composite bionic sand stabilization unit body and a preparation method thereof, and relates to the technical field of sand stabilization, the interior of the unit body is provided with a bionic three-dimensional porous skeleton structure, the unit body comprises a porous core layer, a porous core layer and a porous core layer, the porous core layer takes cleaning sand grains with the particle size of 0.1-2 mm as a sand-based carrier; uniformly mixing and curing with organic nutrient substances, mineral precursors and strain spores; the composite reinforcing layer is formed by interweaving and compounding a mycelium network formed by germination and growth of strain spores, mineral crystals generated by in-situ mineralization induced by metabolic activity of hyphae and a plant fiber reinforcing material which is externally added and embedded into the pores in the pores of the porous core layer; according to the hypha mineral compounded bionic sand stabilization unit body and the preparation method thereof, mold pressing or 3D printing prefabrication is adopted, the structure is controllable, and standardized production and transportation are facilitated; and through a controllable fermentation and gradient dehumidification mineralization culture process, hyphae and minerals are ensured to be uniformly and fully compounded in pores, and the product quality is stable.

Description

Technical Field

[0001] This invention relates to sand fixation technology, specifically to a biomimetic sand fixation unit composed of mycelium and minerals and its preparation method. Background Technology

[0002] Land desertification is a global environmental problem. Traditional sand fixation methods mainly include engineering sand fixation (such as straw checkerboards and stone checkerboards), chemical sand fixation (spraying sand-fixing agents), and plant sand fixation. Engineering sand fixation is costly and has a limited lifespan; chemical sand-fixing agents often pose environmental pollution risks, and the crust they form is prone to cracking; plant sand fixation has a long cycle and a low initial survival rate.

[0003] In recent years, biological sand fixation technology, especially the technology of microbial induced calcium carbonate precipitation (MICP), has attracted attention. However, the mineralized layer formed by this technology is often brittle and lacks toughness, and the environmental adaptability of the microbial strains is limited. How to construct a sand fixation material that combines high strength, good toughness, long-term stability, and ecological affinity, and achieve standardized and modular application, is a current technical challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a biomimetic sand-fixing unit composed of mycelium and minerals and its preparation method, so as to solve the shortcomings of existing biological sand-fixing technologies, such as the high brittleness and insufficient toughness of the mineralized layer and the limited environmental adaptability of the mycelium species.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a biomimetic sand-fixing unit body composed of mycelium and minerals, wherein the unit body has a biomimetic three-dimensional porous skeleton structure with a porosity of 40%-65%;

[0006] The unit body includes:

[0007] The porous core layer is formed by uniformly mixing and solidifying cleaned sand particles with a particle size of 0.1-2mm as a sand-based carrier with organic nutrients, mineral precursors and fungal spores.

[0008] The composite reinforcement layer is composed of three interwoven and composite materials within the pores of the porous core layer: a mycelial network formed by the germination and growth of fungal spores, mineral crystals generated by in-situ mineralization induced by mycelial metabolic activity, and plant fiber reinforcement material added externally and embedded in the pores.

[0009] Furthermore, the biomimetic three-dimensional porous skeleton structure is honeycomb-shaped, mesh-shaped, or a block-shaped structure with internal interconnected channels.

[0010] Furthermore, the mineral precursor is at least one of soluble calcium salt and urea, and soluble silicate.

[0011] Furthermore, the plant fiber reinforcing material is alkali-treated straw fiber, coconut shell fiber, wood chips, or hemp fiber.

[0012] Furthermore, the fungal species is Trichoderma or Mucor.

[0013] Furthermore, the outer surface of the unit is also coated with a biodegradable plant seed bank layer, which is composed of drought-resistant plant seeds, water-soluble coating material and nutrient microcapsules, with a coating thickness of 0.1-0.5 mm.

[0014] A method for preparing a biomimetic sand-fixing unit based on mycelium and mineral composites, applicable to the preparation of such units, includes the following steps:

[0015] S1. After dry mixing the washed sand, organic nutrients, mineral precursor powder, and plant fiber reinforcing material, mix them with the fungal spore suspension to obtain a moist mixture.

[0016] S2. Place the wet mixture into a mold with a biomimetic three-dimensional porous structure, and obtain a green body by compression molding or 3D printing; wherein, the compression molding pressure is 0.5-2MPa; when 3D printing, biodegradable hydrogel is used as the support material, the printing layer thickness is 0.5-2mm, and the extrusion temperature is 20-35℃.

[0017] S3. The green body is first cultured at a temperature of 25-30℃ for 3-5 days, then the temperature is adjusted to 20-35℃ and cultured for another 4-11 days. During this period, the mineralization solution is sprayed every 12 hours. After the culture is completed, it is gently dried to obtain the shaped unit body.

[0018] S4. Mix drought-resistant plant seeds, water-soluble coating materials and nutrient microcapsules, add water to make a suspension, and use a spray drying device to evenly spray the suspension onto the outer surface of the shaped unit body to form a coating layer, thereby obtaining a biomimetic sand-fixing unit body.

[0019] Furthermore, the spray volume of the spray described in S3 is 5-10 mL / m 2 The composition of the mineralization solution corresponds to the mineral precursor.

[0020] Furthermore, the correspondence between the mineralizing solution composition and the mineral precursor is as follows: when the mineral precursor is soluble calcium salt and urea, the mineralizing solution is calcium chloride solution; when the mineral precursor is soluble silicate, the mineralizing solution is sodium silicate solution; when it is a compound system, the mineralizing solution is a mixed solution of calcium salt and silicate.

[0021] Furthermore, the organic nutrient mentioned in S1 is a mixture of glucose, yeast extract and peptone in a mass ratio of 1:0.5:0.2.

[0022] Compared with the prior art, the present invention provides a biomimetic sand-fixing unit body composed of mycelium and mineral composite and its preparation method. The unit body has a biomimetic three-dimensional porous skeleton with high porosity and interconnection, which is conducive to water infiltration, air circulation and subsequent plant root penetration. The mycelium network provides toughness, the in-situ generated mineral crystals provide rigidity, and the plant fiber reinforcement material plays a bridging and toughening role. The three composite and synergistic effects enable the unit body to have high compressive strength, wind erosion resistance and good toughness at the same time, overcoming the disadvantage of the high brittleness of a single mineralized layer.

[0023] Using sand as the main carrier, the strains of bacteria and plant fibers are sourced from environmentally friendly sources, and the mineral formation process is biologically induced, making it environmentally friendly. The plant seed bank layer set on the surface can germinate under suitable conditions, realizing the integration of "sand fixation-habitat improvement-vegetation restoration". Drought-resistant and salt-tolerant filamentous fungi are selected to improve the survival and sustainable function of the unit in the desert environment.

[0024] Prefabricated by molding or 3D printing, the shape, size, and pore structure are controllable, facilitating standardized production and transportation. Through controllable fermentation and gradient dehumidification mineralization cultivation processes, the uniform and full compounding of mycelium and minerals within the pores is ensured, resulting in stable product quality. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0026] Figure 1 This is a schematic diagram of the overall preparation process of the mycelium-mineral composite biomimetic sand-fixing unit provided in an embodiment of the present invention;

[0027] Figure 2 A schematic diagram showing the porosity detection results of the biomimetic sand-fixing unit cell of mycelium mineral composite provided in an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the composition and volume of the biomimetic sand-fixing unit sample of mycelium-mineral composite provided in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the wind erosion rate detection results of the biomimetic sand-fixing unit with mycelium mineral composite provided in an embodiment of the present invention. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] Example 1:

[0032] A biomimetic sand-fixing unit composed of mycelium and mineral composites has a biomimetic three-dimensional porous skeleton structure with a porosity of 40%-65%. The biomimetic three-dimensional porous skeleton structure is honeycomb-like, grid-like, or clump-like with internal interconnected channels.

[0033] The unit includes:

[0034] The porous core layer is formed by uniformly mixing and solidifying cleaned sand particles with a particle size of 0.1-2 mm as a sand-based carrier with organic nutrients, mineral precursors and fungal spores; the mineral precursor is at least one of soluble calcium salts and urea, and soluble silicates; the fungal species is Trichoderma or Mucor.

[0035] The composite reinforcement layer is composed of three interwoven components within the pores of the porous core layer: a mycelial network formed by the germination and growth of fungal spores, mineral crystals generated by in-situ mineralization induced by mycelial metabolic activity, and plant fiber reinforcement material added externally and embedded in the pores. The plant fiber reinforcement material is straw fiber, coconut shell fiber, wood chips, or hemp fiber that has been treated with alkali.

[0036] The outer surface of the unit is also coated with a biodegradable plant seed bank layer, which consists of drought-resistant plant seeds, water-soluble coating material and nutrient microcapsules, with a coating thickness of 0.1-0.5 mm.

[0037] The biomimetic three-dimensional porous skeleton structure (porosity 40%-65%) provides the basic support framework and internal space for the entire unit. Regular structures such as honeycomb and grid patterns effectively distribute external loads (such as wind pressure and trampling), providing excellent compressive and deformation resistance. The interconnected internal channels serve as pathways for water infiltration and air circulation, preventing surface runoff and creating conditions for mycelium and future plant root respiration. The high and interconnected porosity provides a "miniature habitat" for microbial activity, seed germination, and root growth, forming the basis of ecological functions. While maintaining strength, it reduces weight, facilitating transportation and installation.

[0038] Porous core layer:

[0039] Sand particles (washed sand with a particle size of 0.1-2mm) serve as the main skeleton material and the "carrier" for mycelial mineralization. They directly utilize the sand source in the target treatment area, reducing material costs and environmental disturbance. The surface of the sand particles is an ideal substrate for mycelial attachment and mineral crystal precipitation, which can promote the uniform occurrence of mineralization reactions. The accumulation of sand particles of different sizes naturally forms initial pores, which are the spatial basis for the subsequent construction of composite reinforcement layers.

[0040] Organic nutrients provide carbon and nitrogen sources, as well as energy and matter, for the initial germination of fungal spores and early mycelial growth. They are the initial fuel driving the entire "mycelial growth-induced mineralization" biological chain, ensuring that mycelia can quickly colonize in barren sandy environments. After the mycelial network is formed, they are gradually consumed, eventually reducing dependence on exogenous organic matter and enabling the system to transition to self-sustainability.

[0041] Mineral precursors provide the ions (such as Ca) required for hyphal-induced mineralization reactions. 2+ CO3 2- SiO3 2- Under the action of urease secreted by the hyphae, urea hydrolyzes to produce carbonate ions, which combine with calcium ions to form calcium carbonate crystals. This is the most classic biocementing pathway, with high cementing strength and fast speed. It is also possible that in the slightly alkaline environment caused by hyphal metabolism, it can polymerize to form silica gel or silicate minerals, providing another cementing form with good long-term stability and strong weather resistance. Co-precipitation of calcium carbonate and silicate minerals can be achieved to form a composite cementing phase with complementary properties, which may result in even better strength and durability.

[0042] The spores of fungi are the "engine" and "adhesive network weaver" of the entire bioaugmentation process. Trichoderma / Mucor grow rapidly and have strong hyphae, which can quickly build a dense physical network to entangle sand grains. Trichoderma includes at least one of Trichoderma harzianum, Trichoderma viride, Trichoderma cornii, and Trichoderma longifolia. Mucor includes at least one of Rhizopus oryzae, Mucor rotundifolia, and Mucor thunbergii, which can ensure survival and long-term function under harsh field conditions, and have higher ecological safety. In addition to inducing mineralization, the organic acids, polysaccharides, and other substances they secrete are also good natural biological adhesives.

[0043] Composite reinforcement layer:

[0044] The three-dimensional biofiber network of mycelium wraps around sand grains, connects minerals, and grasps plant fibers, giving materials flexibility and tensile strength like "steel bars," resisting stress cracking caused by wet-dry cycles and freeze-thaw cycles; its metabolic activities create a microenvironment, actively inducing minerals to precipitate on its surface or between mycelium; mycelium in a dormant state can regain activity under suitable conditions, further grow or induce new mineralization, and has a certain potential for self-repair and functional continuity.

[0045] In-situ mineralization generates mineral crystals that fill pores, encapsulate hyphae and sand grains, forming a rigid cement, much like "cement," which significantly enhances the compressive strength, wind erosion resistance, and water erosion resistance of the unit cell. Mineral encapsulation can reduce the sensitivity of hyphae to environmental stresses (such as ultraviolet radiation and drought), extending their service life. The formed minerals (such as calcium carbonate) are chemically stable and can provide long-term consolidation effects.

[0046] The short-cut reinforcing phase dispersed in the pores of plant fiber reinforced materials (after alkali treatment) can play a "bridging" role during crack propagation, consuming more energy and greatly improving the fracture toughness and impact resistance of the material; long fibers can interweave into secondary networks, optimizing the internal structure; the fibers themselves can absorb moisture, improving the micro-water environment of the unit cell, which is beneficial to biological activities; removing lignin and hemicellulose from the fiber surface exposes more cellulose hydroxyl groups, enhancing their binding force with hyphae and mineral interfaces.

[0047] The biodegradable plant seed bank layer is attached to the surface of the unit cell as a multifunctional "ecological start-up package". After the unit cell is fixed in sand, rainwater or irrigation water dissolves the water-soluble coating, releasing seeds and nutrients, which germinate directly on the most suitable growth substrate (unit cell), realizing the function of "sand-fixing body" as "seedling cup". The coating ensures that the seeds are fixed on the unit cell and are not blown away by the wind, and the nutrient microcapsules provide key nutrients in the early stage of seedlings, significantly improving the survival rate. After the plant roots grow out, they will penetrate the unit cell and penetrate into the lower layer of sand, forming a dual locking system of "above-ground unit cell sand fixation + underground root system anchoring", realizing the perfect connection and iteration of engineering measures and plant measures.

[0048] In summary, sand grains form the framework, mycelium acts as a living, resilient bonding and driving network, minerals provide rigid chemical bonding, plant fibers serve as the toughening "bones and ligaments," and the seed bank endows it with the ultimate mission of ecological reproduction. This multi-scale, multi-phase synergistic design of "sand-fungus-mineral-fiber-plant" enables this biomimetic sand-fixing unit to transcend the single function of traditional materials, becoming an advanced ecological engineering product with high strength, high toughness, self-sustaining potential, and ecological propulsion capabilities.

[0049] Example 2:

[0050] Please see Figure 1 This embodiment provides a technical solution based on Embodiment 1: a method for preparing a biomimetic sand-fixing unit composed of mycelium and mineral composites, which is applicable to the preparation of the biomimetic sand-fixing unit composed of mycelium and mineral composites in Embodiment 1, comprising the following steps:

[0051] S1: Preparation of wet mixture:

[0052] Dry mixing stage: 5kg of washed sand, 170g of organic nutrients (glucose + yeast extract + peptone), 80g of mineral precursor powder, and 500g of plant fiber reinforcement material are added to a twin-shaft mixer in sequence, and the speed is 300r / min. Dry mix for 15 minutes until the mixture is uniform to obtain the dry mixture.

[0053] The washed sand particles were taken from the surface sand of the desert area. The organic nutrients were 100g of glucose, 50g of yeast extract and 20g of peptone, which were mixed and crushed through an 80-mesh sieve. The mineral precursors were 50g of calcium chloride and 0g of urea, which were mixed and ground into powder. The plant fiber reinforcing material was wheat straw fiber that had been treated with alkali (treated with 5% NaOH solution at 80℃ for 2 hours, washed with water until neutral, and cut into short fibers 1-3mm long).

[0054] Wet mixing stage: 10L of fungal spore suspension was slowly sprayed into the dry mix in three portions, stirring for 5 minutes after each spray, to obtain a moist mix with a moisture content of 20%-25%; the fungal spores were *Trichoderma viride*, prepared in 1×10⁻⁶ batches. 6 A spore suspension of 10 spores per mL was prepared, with a total volume of 10 L.

[0055] S2: Green body forming (molding process):

[0056] A stainless steel biomimetic honeycomb mold (honeycomb pore diameter 8mm, wall thickness 1mm, mold cavity size 10cm×10cm×5cm) is used. The moist mixture is evenly filled into the mold, and a hydraulic press is used to apply a pressure of 1MPa. After holding the pressure for 30s, the mold is demolded to obtain a green body with a complete structure and no cracks. The moisture content of the green body is controlled at 18%-22%.

[0057] S3: Cultivation and Finalization:

[0058] First stage of cultivation: Place the raw material in a constant temperature and humidity incubator, set the temperature to 28℃ and the relative humidity to 85%, and cultivate statically for 4 days. During this stage, the spores of the fungus germinate into mycelium and initially form a three-dimensional network.

[0059] Second stage of cultivation: Adjust the incubator temperature to 25℃ and relative humidity to 70%, and continue cultivation for 8 days; during this period, spray the surface of the green body with 7mL / m² of water every 12 hours. 2 A 0.5 mol / L calcium chloride mineralizing solution was used to ensure sufficient mineralization reaction within the pores;

[0060] After cultivation, the green body was transferred to a 35℃ ventilated drying oven (wind speed 1m / s) and dried for 72 hours until the moisture content was <8%, thus obtaining the shaped unit body.

[0061] S4: Seed bank layer spraying:

[0062] 100g of Artemisia argyi seeds, 200g of polyvinyl alcohol, and 50g of NPK slow-release microcapsules (particle size 50-100μm) were added to 5L of deionized water and stirred at 60℃ for 30min until completely dissolved to form a uniform suspension. The suspension was then uniformly sprayed onto the outer surface of the shaping unit using a spray drying device (nozzle diameter 0.5mm, atomization pressure 0.3MPa). During the spraying process, the unit rotated at a constant speed (10r / min) to ensure a consistent coating thickness. After spraying, the unit was placed in a ventilated environment at 25℃ for 24h to allow the coating layer to fully solidify, ultimately forming a 0.3mm thick biodegradable seed bank layer, thus obtaining a complete biomimetic sand-fixing unit.

[0063] Example 3:

[0064] Please see Figures 2 to 4 This embodiment provides a technical solution based on Embodiment 2: Performance testing experiment of biomimetic sand-fixing unit with mycelial mineral composite:

[0065] 1. Porosity testing:

[0066] Weigh out the dried mass of three biomimetic sand-fixing unit bodies (denoted as A1, A2, and A3) prepared in Example 2, and record the mass as m1 (g). Add 500 mL of deionized water to a graduated cylinder and record the initial volume V1 (mL). Tightly wrap the unit body with plastic wrap (only wrapping the outer surface, without blocking the internal pores), and slowly immerse it in the water in the graduated cylinder. After the liquid level stabilizes, record the final volume V2 (mL). Calculate the volume of the unit body. Based on the sand density (taken as 2.65 g / cm³) 3 Calculate the volume V of the sand grain skeleton using the conventional density of desert sand. 骨 The formula is:

[0067] ;

[0068] The formula for calculating porosity θ is:

[0069] .

[0070] Please refer to the table below for the experimental results:

[0071]

[0072] Please refer to the table above. Figure 2 and Figure 3 The product has a porosity of 55.1% ± 0.1% and good internal pore connectivity (liquid level stabilization time in the drainage method is < 5 min), which can meet the needs of water infiltration, air circulation and plant root penetration.

[0073] 2. Compressive strength test:

[0074] Test unit: In Example 2, six biomimetic sand-fixing units composed of mycelial mineral composites were prepared, divided into three dry states (denoted as B1, B2 and B3) and three wet states (denoted as C1, C2 and C3). The wet units were soaked in deionized water for 2 hours in advance (simulating 10 mm of rainfall) and the surface moisture was drained.

[0075] Place the unit cell in the center of the lower platen of the electronic universal testing machine, and adjust the upper platen to fit the upper surface of the unit cell (without preload); set the loading rate to 1 mm / min (uniform loading, simulating slow load from wind and sand accumulation), until obvious cracks appear in the unit cell (load decrease ≥10%), and record the maximum load F (unit: kN); compressive strength σ = F / S, where S is the area of ​​the unit cell under pressure (0.01 m²). 2 ).

[0076] Please refer to the table below for the experimental results:

[0077]

[0078] Its dry compressive strength reaches 1.21 MPa, and it can withstand the load of a 1.2m thick layer of wind-blown sand (sand density 1.6g / cm³). 3 The load is 1.2 × 1.6 × 10 = 19.2 kPa, which is much lower than 1.21 MPa. The wet compressive strength is 0.80 MPa, which still maintains high mechanical properties. It avoids the problem of "softening when exposed to water" of traditional chemical sand-fixing agents and meets the sand-fixing needs after desert rainfall.

[0079] 3. Wind erosion resistance test:

[0080] Traditional straw checkerboard (same size) and bare desert sand (compacted density 1.5g / cm³) were used. 3 The control group was prepared in Example 2, and the biomimetic sand-fixing unit prepared in Example 2 was prepared in Example 2. The control group and the experimental group were fixed at the bottom of the wind tunnel test section to ensure that they were flush with the bottom surface of the wind tunnel and filled with bare sand around them (to avoid disturbance of the edge airflow).

[0081] The wind tunnel is set at a wind speed of 10 m / s and blown continuously for 24 hours. Every 6 hours, the wind tunnel is closed, and sand particles at the wind tunnel outlet are collected (filtered with filter paper). The wind erosion amount (m) is then measured. 蚀 (Unit: g);

[0082] The wind tunnel was set to a wind speed of 15 m / s and blew continuously for 24 hours. Every 6 hours, the wind tunnel was closed, and sand particles at the wind tunnel outlet were collected (filtered with filter paper). The wind erosion amount (m) was measured. 蚀 (Unit: g);

[0083] The formula for calculating wind erosion rate is as follows:

[0084] ;

[0085] Where m1 is the initial dry weight of the analyte.

[0086]

[0087] Please see Figure 4 As shown in the table above, the wind erosion rate of the unit cell of this invention is only 0.8% in 24 hours at a wind speed of 10m / s, which is much lower than that of traditional grass checkerboard (5.8%) and bare sand (13.5%). Moreover, it can still control the wind erosion rate to ≤2% under strong winds of 15m / s, indicating that the mycelium-mineral-fiber composite structure has a significant "locking ability" for sand particles and can effectively resist desert wind and sand erosion.

[0088] 4. Seed germination rate test:

[0089] Test unit cells: 3 (with Artemisia argyi seed bank layer on the surface);

[0090] Control group: Artemisia seeds were directly sown on bare sand (seed amount was the same as per unit cell, about 1g / unit cell).

[0091] Experimental equipment: artificial climate chamber (temperature 25℃ / 15℃ day and night intermittent, humidity 60%, light 12h / d), spray bottle (simulating rainfall).

[0092] The unit cell and bare sand sample were placed in a climate chamber and a spray bottle was used to simulate 20 mm of rainfall (sprayed twice, 10 mm each time, with an interval of 2 hours).

[0093] Afterwards, spray 5mL of deionized water daily (to keep the surface moist) and observe for 7 consecutive days.

[0094] Record the number of seeds that germinate each day (germination is defined as the radicle breaking through the seed coat by ≥2mm), and calculate the germination rate over 7 days. The formula for calculating the germination rate is as follows:

[0095] ;

[0096] Please refer to the table below for the experimental results:

[0097]

[0098] The "water-soluble coating + nutrient microcapsules" of the seed bank layer on the surface of the unit cell can effectively protect the seeds, and the germination rate reaches 88% in 7 days, which is 2.6 times that of sowing in bare sand. This enables the simultaneous advancement of "sand fixation and vegetation restoration" and meets the needs of ecological sand fixation.

[0099] 5. Mycelial survival period detection:

[0100] Fifteen unit cells were collected (buried in five batches of three each); the experimental site was the Northwest Desert Experimental Area (annual precipitation 180 mm, diurnal temperature range 18 °C).

[0101] The unit cells were buried in the desert surface (5cm deep, simulating the actual sand-fixing laying depth), and samples were taken after 3 months, 6 months, 12 months, 18 months and 24 months.

[0102] Three units were taken from each batch, and three internal samples (5g each) were randomly collected from each unit. The samples were aseptically lysed, then mixed with sterile water and shaken for 30 minutes to prepare a bacterial suspension. The suspension was spread onto PDA medium and incubated at 28°C for 48 hours. The colony count (CFU / g) was determined to assess mycelial viability (colony count ≥ 10). 3 CFU / g indicates survival rate.

[0103] Please refer to the table below for the experimental results:

[0104]

[0105] The mycelium within the unit remained viable after being buried in the field for 18 months (colony count 1.2 × 10⁻⁶). 3 The product (CFU / g) died after 24 months due to extreme drought (annual precipitation <150mm); this indicates that *Trichoderma viride* significantly improves the long-term stability of the product and can meet the initial ecological restoration needs of desert sand fixation for more than 1.5 years.

[0106] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A biomimetic sand-fixing unit body composed of mycelium and mineral composites, characterized in that, The unit body has a biomimetic three-dimensional porous skeleton structure with a porosity of 40%-65%. The unit body includes: The porous core layer is formed by uniformly mixing and solidifying cleaned sand particles with a particle size of 0.1-2mm as a sand-based carrier with organic nutrients, mineral precursors and fungal spores. The composite reinforcement layer is composed of three interwoven and composite materials within the pores of the porous core layer: a mycelial network formed by the germination and growth of fungal spores, mineral crystals generated by in-situ mineralization induced by mycelial metabolic activity, and plant fiber reinforcement material added externally and embedded in the pores.

2. The biomimetic sand-fixing unit body of mycelial mineral composite according to claim 1, characterized in that, The biomimetic three-dimensional porous skeleton structure is honeycomb-shaped, grid-shaped, or a block-shaped structure with internal interconnected channels.

3. The biomimetic sand-fixing unit body of mycelial mineral composite according to claim 1, characterized in that, The mineral precursor is at least one of soluble calcium salt, urea, and soluble silicate.

4. The biomimetic sand-fixing unit body of mycelial mineral composite according to claim 1, characterized in that, The plant fiber reinforcing material is straw fiber, coconut shell fiber, wood chips, or hemp fiber that has been treated with alkali.

5. The biomimetic sand-fixing unit body of mycelial mineral composite according to claim 1, characterized in that, The fungal species are Trichoderma or Mucor.

6. The biomimetic sand-fixing unit body of mycelial mineral composite according to claim 1, characterized in that, The outer surface of the unit is also coated with a biodegradable plant seed bank layer, which is composed of drought-resistant plant seeds, water-soluble coating material and nutrient microcapsules, with a coating thickness of 0.1-0.5 mm.

7. A method for preparing a biomimetic sand-fixing unit composed of mycelial mineral composites, characterized in that, It is applicable to the preparation of a biomimetic sand-fixing unit body of mycelial mineral composite as described in any one of claims 1-6, comprising the following steps: S1. After dry mixing the washed sand, organic nutrients, mineral precursor powder, and plant fiber reinforcing material, mix them with the fungal spore suspension to obtain a moist mixture. S2. Place the wet mixture into a mold with a biomimetic three-dimensional porous structure, and obtain a green body by compression molding or 3D printing; wherein, the compression molding pressure is 0.5-2MPa; when 3D printing, biodegradable hydrogel is used as the support material, the printing layer thickness is 0.5-2mm, and the extrusion temperature is 20-35℃. S3. The green body is first cultured at a temperature of 25-30℃ for 3-5 days, then the temperature is adjusted to 20-35℃ and cultured for another 4-11 days. During this period, the mineralization solution is sprayed every 12 hours. After the culture is completed, it is gently dried to obtain the shaped unit body. S4. Mix drought-resistant plant seeds, water-soluble coating materials and nutrient microcapsules, add water to make a suspension, and use a spray drying device to evenly spray the suspension onto the outer surface of the shaped unit body to form a coating layer, thereby obtaining a biomimetic sand-fixing unit body.

8. The method for preparing a biomimetic sand-fixing unit of mycelial mineral composite according to claim 7, characterized in that, The spray volume of S3 is 5-10 mL / m 2 The composition of the mineralization solution corresponds to the mineral precursor.

9. The method for preparing a biomimetic sand-fixing unit of mycelial mineral composite according to claim 8, characterized in that, The correspondence between the mineralizing solution composition and the mineral precursor is as follows: when the mineral precursor is soluble calcium salt and urea, the mineralizing solution is calcium chloride solution; when the mineral precursor is soluble silicate, the mineralizing solution is sodium silicate solution; when it is a compound system, the mineralizing solution is a mixed solution of calcium salt and silicate.

10. The method for preparing a biomimetic sand-fixing unit of mycelial mineral composite according to claim 7, characterized in that, The organic nutrient mentioned in S1 is a mixture of glucose, yeast extract and peptone in a mass ratio of 1:0.5:0.2.

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