Preparation method and application of mycelium composite building biological material

Abstract

The application discloses a preparation method and application of mycelium composite building biological material, and adopts agricultural and forestry wastes such as cottonseed hulls and bamboo chips to prepare a culture medium, then inoculates the liquid fungus strain which has been expanded for three times in the culture medium, and finally obtains the mycelium composite building biological material through mycelium culture, moulding, constant-temperature fungus culture and microwave drying and inactivation, wherein the fungus has different temperature types to adapt to annual production and greatly reduce the energy consumption for maintaining the optimum growth conditions. The mycelium composite building biological material prepared through the preparation method has the advantages of neat mycelium, uniform thickness, consistent color, no bacterial contamination, high uniformity, B-level fireproofing, high bending strength, shear strength and compressive strength, 0.85 kJ / kg.C of specific heat, 0.028-0.075 W / m.C of thermal conductivity, and good fireproofing, heat insulation, noise reduction and other performances.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of bio-building material preparation, and particularly relates to a preparation method and application of a mycelium composite building bio-material. BACKGROUND

[0002] The production of traditional building materials consumes a large amount of mineral resources and fossil energy, and the generated construction waste is difficult to degrade and recycle, and can only be stored, which seriously affects the environment. With the development of society and the acceleration of industrialization and urbanization, the production, utilization, abandonment and recycling of building materials have caused more and more serious damage and depletion of natural resources, and the contradiction between environment and development is becoming increasingly serious. Therefore, producing natural and environmentally friendly bio-composite materials that are easy to obtain, renewable, easy to process and degradable has become a new trend in the building field. For example, JP2011178157A, CN106147276A, US07534485B2, US06787590B2 and CN102337783B all disclose the preparation and application of various bio-composite materials.

[0003] There are about 2.5 million species of fungi belonging to microorganisms in the global biosphere, which are widely distributed in soil, water, animals and plants, and their residues and air all over the world, and exist in the form of saprophytic, parasitic and symbiotic. Fungi are the main decomposers in nature, and the extracellular enzymes produced by them continuously decompose cellulose and lignin in the nutrient matrix into simple small molecules, helping the degradation of organic matter, and then absorbing nutrients such as carbon source, nitrogen source, phosphorus and other trace elements to carry out a large amount of growth and reproduction. Fungi produce a large amount of mycelium during the reproduction process, and the mycelium is interwoven to form a dense population, which is called mycelium. When fungi are implanted into a suitable substrate, the mycelium will glue the substrate together like glue, making it solid. Commonly used fungal substrates can be sawdust, ground wood, straw, various crop residues or other similar materials, and these materials are usually discarded.

[0004] According to different strains and substrates, finally, shaped insulation boards, clamps, accessories, fabrics, packaging materials, and reproductive bricks can be produced, which have good thermal and acoustic properties and strong fireproof performance. Studies have shown that in terms of physical and mechanical properties, mycelium materials are similar to expanded polystyrene (often referred to as polystyrene foam), but the degradability is improved, so mycelium can be used to produce building materials. For example, The Living studio and Ecovative Design design company cooperated to complete an exhibition building, which used corn stalks and mycelium to prepare mycelium bricks, and then used the mycelium bricks to build a tower about 12 meters high. After the exhibition, the tower was dismantled and the mycelium bricks were sent to a composting plant for degradation and recycling. CN113930081A discloses a preparation method for building filling mycelium composite block, which mixes sterilized sandstone, starch aqueous solution, and edible fungus waste fungus bag, then fills the mixture into a mold and compacts, takes out after a period of cultivation, and continues to cultivate for a period of time, then dries and inactivates to obtain mycelium composite block. CN106380166A discloses a fungal mycelium composite insulation board and a preparation method thereof, which uses inorganic lightweight aggregate and nutrient solution to prepare a culture medium, and then uses the culture medium to cultivate fungal mycelium to obtain mycelium mixture, which can replace inorganic lightweight aggregate to press into an insulation board, so that it has good thermal insulation performance and crack resistance.

[0005] However, the existing production process of composite biomaterials is to directly inoculate fungal strains into the culture medium, which makes the preparation of biomaterials containing mycelium still remain in the laboratory stage and cannot be produced on a large scale. At the same time, the optimum growth temperature of each strain is different, so a large amount of energy is consumed to maintain the optimum growth conditions of the strain in the process of annual production, so as to ensure that the produced composite biomaterials have good quality and uniformity. In addition, there is no specific qualitative research on the drying method and drying index of the prepared composite biomaterials. The conventional drying and inactivation process is to heat the material from the outside, and when the inside of the composite biomaterial is dry, the surface of the material is easy to crack due to high temperature heating, which seriously affects the appearance and strength of the product. When the thickness or diameter of the composite biomaterial is too large, the water content in the center is often high after the surface is dried, which can easily become soft, rotten, and even cause the composite biomaterial to be scrapped directly in the later storage or use, which seriously affects the application of the composite biomaterial. SUMMARY

[0006] In order to solve the above technical problems, the present application provides a preparation method and application of mycelium composite building biological material, a culture medium is prepared by using agricultural and forestry wastes, then different temperature type strains are inoculated in the culture medium through three-stage propagation, and the mycelium composite building biological material is prepared by mycelium culture, mold loading, constant temperature cultivation, and microwave drying and inactivation, which can be used for year-round production, reduces energy consumption, and improves the uniformity of the mycelium composite building biological material.

[0007] In order to achieve the above purpose, the present application provides a preparation method of mycelium composite building biological material, comprising the following steps:

[0008] (1) Preparation of culture medium: agricultural and forestry wastes are crushed and mixed with water, and then bagged after uniform stirring to obtain a bagged culture medium;

[0009] (2) Culture medium treatment: the bagged culture medium in step (1) is subjected to high-pressure steam sterilization, and then placed in a cooling chamber for cooling;

[0010] (3) Strain propagation: the strain mother culture is activated by using three-stage propagation technology to obtain a liquid production strain;

[0011] (4) Inoculation: the liquid strain obtained in step (3) is inoculated into the bagged culture medium cooled in step (2) to obtain a fungus bag;

[0012] (5) Mycelium culture: constant temperature cultivation for 5-7 days;

[0013] (6) Mold loading: the culture medium in the fungus bag after mycelium culture is taken out and placed in a mold for compaction and sealing;

[0014] (7) Constant temperature cultivation: temperature control according to the type and season of the strain, and constant temperature cultivation in the dark for 7-10 days, with daily scheduled ventilation;

[0015] (8) After the culture medium in the mold in step (7) is fully covered with mycelium, it is taken out and subjected to microwave inactivation to obtain mycelium composite building biological material with uniform mycelium, uniform thickness, consistent color and no bacterial contamination, and the mycelium material that does not meet the requirements is crushed and reused.

[0016] Preferably, the agricultural and forestry wastes in step (1) are composed of 40%-50% cottonseed hulls, 20-30% industrial hemp stalks and 20-30% bamboo chips, and the length of the crushed agricultural and forestry wastes is 3-150 mm, and the water content of the culture medium is 55%-60%.

[0017] Preferably, the cooling chamber in step (2) has a cleanliness of 10,000, and the internal temperature of the bagged culture medium after cooling is 20-25℃.

[0018] Preferably, the strain in step (3) is a strain with different temperature types.

[0019] More preferably, the strains of different temperature types are low-temperature oyster mushroom, medium-temperature oyster mushroom, and high-temperature oyster mushroom.

[0020] Preferably, the inoculation amount in step (4) is 8%-15%.

[0021] Preferably, the temperature for constant temperature culture in step (7) is controlled at 14-16℃ in winter, 25-27℃ in summer, and 20-22℃ in spring and autumn. The ventilation time is as follows: in winter, no ventilation is provided for the first 1-2 days of culture, ventilation is provided 1-2 times a day for 0.5-1 hours each time for the third to fifth days, and 2-3 times a day for 1-1.5 hours each time for the sixth to tenth days. In spring, summer and autumn, no ventilation is provided for the first 1-2 days of culture, ventilation is provided 2-3 times a day for 1-1.5 hours each time for the third to fifth days, and 3-4 times a day for 1.5-2 hours each time for the sixth to tenth days.

[0022] Preferably, the microwave inactivation in step (8) is a tunnel-type microwave drying inactivation, wherein the microwave frequency is 2-3 GHz, the extinguishing time is 10-15 min, and the moisture content of the mycelium composite building biomaterial is <10%.

[0023] More preferably, the microwave frequency is 2.45 GHz.

[0024] This invention also provides an application of mycelial composite building biomaterial in the field of fireproof and heat-insulating building materials.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. Using agricultural and forestry wastes such as cottonseed hulls, industrial hemp stalks, and bamboo shavings as culture media for mycelium cultivation not only makes use of waste and reduces production costs, but also enables the final mycelium composite building biomaterial to degrade rapidly, reducing its environmental impact.

[0027] 2. By using mycelial strains of the same variety with different temperature types for the production and preparation of mycelial composite building biomaterials, suitable strains can be selected according to changes in ambient temperature during year-round production. Specifically, high-temperature strains are selected in summer, low-temperature strains in winter, and medium-temperature strains in spring and autumn. While ensuring the quality and uniformity of the produced mycelial composite building biomaterials, energy conservation and consumption reduction are greatly achieved, production costs are lowered, and the ecological environment is protected.

[0028] 3. The two-step method of first inoculating the culture medium and then molding and cultivating the culture medium is adopted. After inoculation, the inoculum is allowed to germinate on the culture medium first, so that the inoculated inoculum is the main and absolutely dominant microbial community on the culture medium. This avoids the contamination of the mold with bacteria during the later molding process, improper operation, poor sealing, transportation from the inoculation room to the constant temperature culture room, and the contamination of the culture room due to insufficient cleanliness. It can improve the yield of good products by 20%. Especially in the hot and humid natural environment of spring and summer, when the number of contaminants in the air is high, the yield of good products can be improved by 50%.

[0029] 4. The "tunnel-structure microwave drying and inactivation" method utilizes the penetrating power of microwaves to treat the mycelial material product as a whole, affecting both the surface and the interior simultaneously. It is unaffected by thickness or size, ensuring uniform and thorough inactivation. This method overcomes the problems of existing technologies that cause surface cracking due to high-temperature heating, affecting product appearance and strength, and failing to achieve adequate drying of the central part of thick or large-diameter mycelial materials, leading to softening or even decay in the center and product spoilage. Furthermore, unlike thermal inactivation which results in heat loss in equipment and the environment, microwaves act directly on the product without heat loss, saving 30%-50% of energy. The tunnel-structure microwave inactivation method allows for mechanized and automated conveyor belt production lines, ensuring the final mycelial composite building biomaterial has a uniform moisture content of less than 10%, improving uniformity. It also offers advantages such as simple and convenient operation, high production efficiency, and reduced labor costs. Attached Figure Description

[0030] Figure 1 The qualified mycelial material prepared in Example 1.

[0031] Figure 2 The mycelial material prepared by hot air drying in Comparative Example 1 is shown in the figure. A is the mycelial material with surface cracks, and B is the mycelial material that has become soft and smelly after being stored for a period of time.

[0032] Figure 3 The mycelial material used in Comparative Example 2 was contaminated with bacteria. Detailed Implementation

[0033] The technical solution of the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention should be determined by the contents of the claims. Modifications and substitutions made by those skilled in the art to the technical solution of the present invention without creative effort all fall within the scope of protection of the present invention.

[0034] The mushroom strains: low-temperature oyster mushroom strains, medium-temperature oyster mushroom strains, and high-temperature oyster mushroom strains were all purchased from Hubei Senyuan Ecological Technology Co., Ltd.

[0035] Example 1

[0036] (1) Preparation of culture medium: Take 50% cottonseed hulls, 25% industrial hemp straw, and 25% bamboo shavings, add water and stir evenly, and pack into bags to prepare a bagged culture medium with a water content of 55%. The length of cottonseed hulls, industrial hemp straw, and bamboo shavings is 3-150mm, and the weight of the bagged culture medium is 2.5-15kg.

[0037] (2) Place the bagged culture medium in a high-pressure steam sterilizer and sterilize it at 121℃ and 0.1-0.15MPa for 2 hours. Then place it in a cooling room with a cleanliness level of 10,000 to cool it down to 20-25℃.

[0038] (3) Spawn propagation: The low-temperature type oyster mushroom primary spawn was taken out of the refrigerator and activated at room temperature for 3-5 hours. It was then inoculated into an Erlenmeyer flask containing PDA liquid medium without agar for propagation to obtain primary spawn liquid culture solution. The primary spawn liquid culture solution was then inoculated into a secondary spawn fermenter for propagation to obtain the propagated secondary spawn liquid culture solution. Finally, the secondary spawn liquid culture solution was inoculated into a tertiary spawn fermenter for propagation. The culture medium formulas in the secondary and tertiary spawn fermenters were: corn flour 0.5%, soybean meal flour 0.5%, molasses 0.8%, K2HPO4 0.05%, MgSO4 0.03%. The inoculation amount was calculated based on the liquid volume of the fermenter, which was 70% of the effective filling volume coefficient. Based on this base, an inoculation amount of 8% was used to obtain the propagated tertiary spawn liquid culture solution.

[0039] (4) In the inoculation room, the third-level inoculum obtained in step (3) is inoculated into the bagged culture medium prepared in step (2). The cleanliness of the inoculation operation area is Class 100. Use a special inoculation gun to inoculate each bag at three inoculation points (top, middle, and bottom). The inoculation amount at each inoculation point is 10 mL. After inoculation, mix the inoculum with the culture medium evenly and reseal the inoculum bag.

[0040] (5) Place the mushroom bags at a constant temperature of 14-16℃, away from light, and incubate for 5-7 days to allow the mushroom spawn to fully germinate and grow.

[0041] (6) Prepare a 240mm×115mm×53mm mold, wipe it with 75% alcohol in a clean room, then put the culture medium that has germinated in step (5) into the mold, compact it, and seal it with a bag.

[0042] (7) Transfer the mold obtained in step (6) to a constant temperature incubation room and incubate at 14-16℃ in the dark for 7-10 days. Ventilate the incubation room regularly every day, and increase the ventilation time and frequency as the mycelial growth rate and incubation time increase. The ventilation time and frequency are as follows: no ventilation for the first 1-2 days of incubation; ventilation begins on the 3rd day; from the 3rd to the 5th day, each ventilation session lasts 0.5-1 hour and is 1-2 times per day; from the 6th to the 10th day, each ventilation session lasts 1-1.5 hours and is 2-3 times per day.

[0043] (8) After the culture medium in the mold is fully covered with mycelium, it is transferred to the tunnel microwave fire extinguishing workshop, the plastic bag and the mold are removed and placed on the conveyor belt. It is extinguished at 2.45 GHz for 10-15 minutes to obtain mycelium composite building biomaterial with neat mycelium, uniform thickness, uniform color and no contamination by miscellaneous bacteria with a water content of <10%. Mycelium materials that do not meet the requirements are crushed and mixed into the culture medium for reuse.

[0044] Example 2

[0045] (1) Preparation of culture medium: Take 45% cottonseed hulls, 25% industrial hemp straw, and 30% bamboo chips, add water and stir evenly, and pack into bags to prepare a bagged culture medium with a water content of 57%. The length of cottonseed hulls, industrial hemp straw, and bamboo chips is 3-150 mm, and the weight of the bagged culture medium is 2.5-15 kg.

[0046] (2) Place the bagged culture medium in a high-pressure steam sterilizer and sterilize it at 121℃ and 0.1-0.15MPa for 2 hours. Then place it in a cooling room with a temperature of Class 10,000 to cool it down to 20-25℃.

[0047] (3) Spawn propagation: Take the mesophilic oyster mushroom primary spawn out of the refrigerator, activate it at room temperature for 3-5 hours, and inoculate it into an Erlenmeyer flask containing PDA liquid medium without agar for propagation to obtain primary spawn liquid culture solution; then inoculate the primary spawn liquid culture solution into a secondary spawn fermenter for propagation to obtain the propagated secondary spawn liquid culture solution; finally, inoculate the secondary spawn liquid culture solution into a tertiary spawn fermenter for propagation. The culture medium formula in the secondary and tertiary spawn fermenters is: corn flour 0.5%, soybean meal flour 0.5%, molasses 0.8%, K2HPO4 0.05%, MgSO4 0.03%. The inoculation amount is calculated based on the liquid volume of the fermenter with an effective filling coefficient of 70% of the fermenter volume. Based on this base, inoculate at a rate of 10% to obtain the propagated tertiary spawn liquid culture solution.

[0048] (4) In the inoculation room, the third-level inoculum obtained in step (3) is inoculated into the bagged culture medium prepared in step (2). The cleanliness of the inoculation operation table area is Class 100. Use a special inoculation gun to inoculate each bag with 9 inoculation points at the top, middle and bottom. The inoculation amount at each inoculation point is 12mL. After inoculation, mix the inoculum with the culture medium evenly and reseal the inoculum bag.

[0049] (5) Place the mushroom bags at a constant temperature of 20-22℃, away from light, and incubate for 5-7 days to allow the mushroom spawn to fully germinate and grow.

[0050] (6) Prepare a 240mm×115mm×53mm mold, wipe it with 75% alcohol in a clean room, then put the culture medium that has germinated in step (5) into the mold, compact it, and seal it with a bag.

[0051] (7) Transfer the mold obtained in step (6) to a constant temperature incubation room and incubate at 20-22℃ in the dark for 7-10 days. Ventilate the incubation room regularly every day, and increase the ventilation time and frequency as the mycelial growth rate and incubation time increase. No ventilation is required for the first 1-2 days of incubation; ventilation begins on the 3rd day. From the 3rd to the 5th day, each ventilation session lasts 1-1.5 hours and is 2-3 times a day. From the 6th to the 10th day, each ventilation session lasts 1.5-2 hours and is 3-4 times a day.

[0052] (8) After the culture medium in the mold is fully covered with mycelium, it is transferred to the tunnel microwave fire extinguishing workshop, the plastic bag and the mold are removed and placed on the conveyor belt, and extinguished at 2.45 GHz for 10-15 minutes to obtain mycelium composite building biomaterial with neat, uniform thickness, uniform color and no contamination of miscellaneous bacteria with a water content of <10%.

[0053] Example 3

[0054] (1) To prepare the culture medium, take 40% cottonseed hulls, 30% industrial hemp straw, and 30% bamboo chips, add water and stir evenly, and pack into bags to prepare a bagged culture medium with a water content of 60%. The length of the cottonseed hulls, industrial hemp straw, and bamboo chips is 3-150 mm, and the weight of the bagged culture medium is 2.5-15 kg.

[0055] (2) Place the bagged culture medium in a high-pressure steam sterilizer and sterilize it at 121℃ and 0.1-0.15MPa for 2 hours. Then place it in a cooling room with a temperature of Class 10,000 to cool it down to 20-25℃.

[0056] (3) Spawn propagation: The high-temperature type oyster mushroom primary spawn was taken out of the refrigerator and activated at room temperature for 3-5 hours. It was then inoculated into an Erlenmeyer flask containing PDA liquid medium without agar for propagation to obtain primary spawn liquid culture solution. The primary spawn liquid culture solution was then inoculated into a secondary spawn fermenter for propagation to obtain the propagated secondary spawn liquid culture solution. Finally, the secondary spawn liquid culture solution was inoculated into a tertiary spawn fermenter for propagation. The culture medium formulas in the secondary and tertiary spawn fermenters were: corn flour 0.5%, soybean meal flour 0.5%, molasses 0.8%, K2HPO4 0.05%, MgSO4 0.03%. The inoculation amount was calculated based on the liquid volume of the fermenter, which was 70% of the effective filling volume coefficient. Based on this base, 15% of the liquid volume was inoculated to obtain the propagated tertiary spawn liquid culture solution.

[0057] (4) In the inoculation room, the third-level inoculum obtained in step (3) is inoculated into the bagged culture medium prepared in step (2). The cleanliness of the inoculation operation area is Class 100. Use a special inoculation gun to inoculate 15 inoculation points evenly distributed at the top, middle and bottom of each bag. The inoculation amount at each inoculation point is 15 mL. After inoculation, the inoculum and culture medium are mixed evenly and the bags are resealed.

[0058] (5) Place the mushroom bags at a constant temperature of 25-27℃, away from light, and incubate for 5-7 days to allow the mushroom spawn to fully germinate and grow.

[0059] (6) Prepare a 240mm×115mm×53mm mold, wipe it with 75% alcohol in a clean room, then put the culture medium that has germinated in step (5) into the mold, compact it, and seal it with a bag.

[0060] (7) Transfer the mold obtained in step (6) to a constant temperature incubation room and incubate at 25-27℃ in the dark for 7-10 days. Ventilate the incubation room regularly every day, and increase the ventilation time and frequency as the mycelial growth rate and incubation time increase. Do not ventilate for the first 1-2 days of incubation; start ventilation on the 3rd day. For the 3rd-5th days, each ventilation time is 1-1.5 hours and the number of ventilations per day is 2-3 times. For the 6th-10th days, each ventilation time is 1.5-2 hours and the number of ventilations per day is 3-4 times.

[0061] (8) After the culture medium in the mold is fully covered with mycelium, it is transferred to the tunnel microwave fire extinguishing workshop, the plastic bag and the mold are removed and placed on the conveyor belt, and extinguished at 2.45 GHz for 10-15 minutes to obtain mycelium composite building biomaterial with neat, uniform thickness, uniform color and no contamination of miscellaneous bacteria with a water content of <10%.

[0062] Comparative Example 1

[0063] The method and steps are the same as in Example 1, except that the microwave drying in step (8) is replaced by conventional hot air drying. The conditions for hot air drying are as follows: drying at high temperature of 75°C for 24 hours; drying at medium-high temperature of 55°C for 36 hours; and drying at a gradient temperature from low to high, first at 45°C for 16 hours, then at 55°C for 8 hours, and finally at 75°C for 2.5 hours. Mycelial materials are obtained by drying using these three methods.

[0064] The results are as follows Figure 1 As shown, the mycelial materials prepared by the three conventional hot air drying methods all exhibit surface cracking. After a period of storage, due to insufficient drying in the central part, the mycelium begins to grow again, resulting in soft rot in the central part of the mycelial material and foul odor.

[0065] Comparative Example 2

[0066] (1) To prepare the culture medium, take 50% cottonseed hulls, 25% industrial hemp straw, and 25% bamboo shavings, add water and stir evenly, and pack into bags to prepare a bagged culture medium with a water content of 55%. The length of the cottonseed hulls, industrial hemp straw, and bamboo shavings is 3-150 mm, and the weight of the bagged culture medium is 2.5-15 kg.

[0067] (2) Place the bagged culture medium in a high-pressure steam sterilizer and sterilize it at 121℃ and 0.1-0.15MPa for 2 hours. Then place it in a cooling room with a temperature of Class 10,000 to cool it down to 20-25℃.

[0068] (3) Spawn propagation: Take the high-temperature type oyster mushroom primary spawn out of the refrigerator, activate it at room temperature for 3-5 days, and inoculate it into an Erlenmeyer flask containing PDA medium (without agar) for propagation to obtain primary spawn liquid culture solution; then inoculate the primary spawn liquid culture solution into a secondary spawn fermenter for propagation to obtain the propagated secondary spawn liquid culture solution; finally, inoculate the secondary spawn liquid culture solution into a tertiary spawn fermenter for propagation. The culture medium formula is: corn flour 0.5%, soybean meal flour 0.5%, molasses 0.8%, K2HPO4 0.05%, MgSO4 0.03%. The inoculation amount is calculated based on the liquid volume of the fermenter with an effective filling coefficient of 70% of the fermenter volume. Based on this base, inoculate at a rate of 15% to obtain the propagated tertiary spawn liquid culture solution.

[0069] (4) In the inoculation room, the bagged culture medium prepared in step (2) is placed in a 240mm×115mm×53mm mold that has been disinfected with 75% alcohol and compacted. Then, on the cleanliness level of the area is Class 100, the third-level inoculum obtained in step (3) is inoculated onto the surface of the culture medium in the mold using a special inoculation gun. Four inoculation points are evenly distributed in each mold, and the inoculation amount at each inoculation point is 15mL. After inoculation, the inoculum is spread to cover the surface of the culture medium in the mold, and the mold is sealed with a film or plastic bag.

[0070] (5) Place the sealed mold obtained in step (4) at a constant temperature of 25-27℃, away from light, and incubate until the mycelium fully grows on the culture medium.

[0071] (6) After the culture medium inside the mold is fully covered with mycelium, remove the sealing film or plastic bag outside the mold, then demold and perform tunnel microwave drying under the same drying conditions as in Example 1 to prepare mycelium composite material.

[0072] The mycelial composite material produced by this method involves direct molding and cultivation of bacteria after inoculation. Since the inoculated fungi have not yet begun to germinate and grow on the culture medium, and have not yet formed a dominant population in the logarithmic growth phase, slight errors in molding, such as with the mold, inoculation environment, or operational procedures, can easily lead to contamination by other microorganisms. Figure 2 During the process of transporting the mold to the incubation room and placing it on the shelves in the incubation room, factors such as damaged sealing film, incomplete sealing film, and unclean incubation environment can easily lead to contamination by miscellaneous bacteria. After the mycelial material is infected by miscellaneous bacteria, it will cause the mycelial growth to slow down or stop. Rhizopus, green mold, and other miscellaneous bacteria will grow rapidly, and the surface of the material will be a variety of colors such as red, white, green, and black, with uneven color. Worse still, it will cause the mycelial material to fail to meet the standards for strength, density, and other parameters, or even become unusable.

[0073] Comparative Example 3

[0074] The method and steps are the same as in Example 1, except that in step (4), the primary liquid spawn of low-temperature oyster mushroom is directly inoculated into the bagged culture medium to prepare the mycelial composite material. Existing technology involves propagating the spawn in Erlenmeyer flasks. A 500mL Erlenmeyer flask can only hold 200mL of spawn. In step (2) of Example 1, the sterilized bagged culture medium (2.5kg) is used. Each bag is inoculated at 3 inoculation points, with 15mL inoculated at each point. Therefore, each bag requires 45mL of spawn, and a single Erlenmeyer flask can only inoculate a maximum of 4 bags of culture medium. This method is far from meeting the requirements of large-scale industrial production. Only by propagating the spawn through three stages can large-scale industrial production be achieved. For example, a 1T secondary spawn fermentation tank with a filling coefficient of 70% can hold 700L of liquid. With an inoculation rate of 10%, 70L of primary liquid spawn is required. After 5-7 days of propagation, 700L of secondary inoculum liquid was obtained. Similarly, with a fill factor of 70% and an inoculum size of 10%, it could be inoculated into a 10-ton tertiary inoculum fermenter. After another 5-7 days of propagation, 7000L of tertiary inoculum liquid was finally obtained. Only through tertiary propagation at a tenfold scale can a large quantity of liquid inoculum be produced in a short time to meet the demands of large-scale production.

[0075] Result detection:

[0076] The mycelial composite building biomaterials from the above embodiments and comparative examples were tested for fire resistance, strength, and other physicochemical properties according to the following relevant standards:

[0077] GB / T32064-2015: Transient planar heat source test for thermal conductivity and thermal diffusivity of building materials;

[0078] GB / T32981-2016: Determination of equivalent thermal conductivity of wall materials;

[0079] ASTM E1530-11(2016): Standard test method for evaluating the resistance to thermal transfer of materials by protected heat flow meter technique;

[0080] ASTM C203-22: Standard test method for breaking load and flexural properties of block insulation materials;

[0081] ASTM E119-22: Standard test methods for fire resistance testing of building structures and materials;

[0082] GB / T20284: Fire resistance test of individual building materials (Chinese standard);

[0083] GB8624: Classification of the fire performance of building materials and products.

[0084] The results are shown in the table below:

[0085]

[0086]

[0087] The above results indicate that:

[0088] Examples 1, 2, 3, and Comparative Example 3 all yielded high-performance thermal insulation materials with thermal conductivity ranging from 0.061 to 0.078 W / m·℃ and a fire rating of Class B. The energy consumption during the production process (i.e., the reflected energy consumption) was only 1.26-1.34 MJ / FU. This is only 10% of the average reflected energy consumption of traditional insulation materials. This indicates that this method can be used to produce low-carbon, green building insulation materials.

[0089] The microwave inactivation and drying equipment used in this method, compared with traditional heating inactivation and drying methods, not only enables uniform drying of mycelial materials, but also ensures thorough drying of the material's interior without causing surface cracking. This results in mycelial materials with higher Young's modulus, compressive strength, and thermal conductivity, leading to broader application prospects. At the same time, the energy consumption of the production process is significantly reduced, which helps to lower production costs and aligns with the concept of green and environmentally friendly production.

[0090] In Comparative Example 2, the method of directly loading molds for mycelial cultivation after inoculation resulted in an extremely high contamination rate during the production of mycelial materials, which could easily lead to a significant waste of manpower and resources. Therefore, it is not suitable for the production of mycelial materials.

Claims

1. A method for preparing a mycelial composite building biomaterial, characterized in that: Includes the following steps: (1) Preparation of culture medium: Take agricultural and forestry waste, crush it, add water and mix it. After stirring evenly, pack it into bags to obtain bagged culture medium; (2) Culture medium treatment: The bagged culture medium from step (1) is autoclaved and then placed in a cooling room to cool; (3) Propagation of strains: The mother strain is activated by a three-stage propagation technique and liquid production strains are obtained through liquid fermentation; (4) Inoculation: The liquid inoculum obtained in step (3) is inoculated into the cooled bagged culture medium in step (2) to obtain the inoculum bag; (5) Mycelium incubation: Incubate at a constant temperature for 3-7 days; (6) Molding: Take out the culture medium from the mycelium bag after mycelium incubation, place it in the mold, compact it, and seal it; (7) Constant temperature culture: The temperature is controlled according to the type of bacteria and the season. The bacteria are cultured in the dark and at a constant temperature for 7-10 days, with regular ventilation every day. (8) After the culture medium in the mold in step (7) is fully covered with mycelium, it is taken out and microwaved to inactivate it, so as to obtain mycelium composite building biomaterial with neat mycelium, uniform thickness, consistent color and no contamination by other bacteria. Mycelium materials that do not meet the requirements are crushed and reused. The agricultural and forestry waste mentioned in step (1) consists of 40%-50% cottonseed hulls, 20%-30% industrial hemp straw and 20%-30% bamboo chips. The length of the crushed agricultural and forestry waste is 3-150 mm, and the moisture content of the culture medium is 55%-60%. In step (7), the temperature for constant temperature culture is controlled at 14-16℃ in winter, 25-27℃ in summer, and 20-22℃ in spring and autumn. The ventilation time is as follows: in winter, there is no ventilation for the first 1-2 days of culture, and ventilation is carried out 1-2 times a day for 0.5-1 hours each time for the third to fifth days. For the sixth to tenth days, ventilation is carried out 2-3 times a day for 1-1.5 hours each time. In spring, summer and autumn, there is no ventilation for the first 1-2 days of culture, and ventilation is carried out 2-3 times a day for 1-1.5 hours each time for the third to fifth days. For the sixth to tenth days, ventilation is carried out 3-4 times a day for 1.5-2 hours each time.

2. The method for preparing a mycelial composite building biomaterial according to claim 1, characterized in that: The cleanliness of the cooling chamber in step (2) is Class 10,000, and the internal temperature of the bagged culture medium after cooling is 20-25℃.

3. The method for preparing a mycelial composite building biomaterial according to claim 1, characterized in that: The strains mentioned in step (3) are strains with different temperature types.

4. The method for preparing a mycelial composite building biomaterial according to claim 3, characterized in that: The different temperature-type strains are low-temperature oyster mushroom, medium-temperature oyster mushroom, and high-temperature oyster mushroom.

5. The method for preparing a mycelial composite building biomaterial according to claim 1, characterized in that: The inoculation amount mentioned in step (4) is 5%-15%.

6. The method for preparing a mycelial composite building biomaterial according to claim 1, characterized in that: The microwave inactivation described in step (8) is a tunnel-type microwave drying inactivation, wherein the microwave frequency is 2-3 GHz, the inactivation time is 10-15 min, and the water content of the mycelium composite building biomaterial is <10%.

7. The method for preparing a mycelial composite building biomaterial according to claim 6, characterized in that: The microwave frequency is 2.45 GHz.

8. The application of the mycelium composite building biomaterial prepared by the method of any one of claims 1-7 in the field of fireproof and heat-insulating building materials.

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