Composite mycelium imitation leather material and preparation method thereof

Abstract

The invention discloses a composite mycelium imitation leather material and a preparation method thereof, and relates to the technical field of composite materials. The preparation method comprises the following steps: homogenizing mycelia to form mycelium slurry, then mixing the mycelium slurry with a modified polyvinyl alcohol solution to obtain a mixture, then adding glycerol, uniformly stirring, pouring into a mold after bubbles are eliminated, and after low-temperature treatment and drying treatment, stripping a mycelium material from the mold to obtain a mycelium material; the mycelium imitation leather material is obtained; the mycelia are mycelia of poriaceae fungi. The preparation method has the advantages of high production efficiency, easiness in large-scale production, simplicity in operation, short production period and the like, and the composite mycelium imitation leather material prepared by the preparation method has good mechanical properties including relatively high tensile strength, tear strength, flexibility and the like, and can fully meet the requirements of imitation leather products.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly to a composite mycelium leather-like material and a preparation method thereof. Background Art

[0002] Mycelium is the vegetative body of fungi, composed of a large number of filamentous hyphae. It has unique biological characteristics, such as being able to grow on a variety of organic substrates, having a fast reproduction rate, and being able to form complex three-dimensional structures through biosynthesis. These characteristics make mycelium show great potential in leather manufacturing. Mycelium can naturally intertwine during growth to form a sheet structure with a certain strength and flexibility, which is similar to the natural texture and physical properties of leather. Moreover, the growth of mycelium can utilize various renewable organic wastes as substrates, such as straw and wood chips in agricultural production, converting these substances that were originally regarded as garbage into valuable materials.

[0003] At present, there are various methods for preparing mycelium leather-like materials, generally based on solid-state culture mode and liquid surface culture mode. Both of these preparation modes have defects such as cumbersome process operations, high labor intensity, and long production cycles, resulting in relatively high production costs. The present invention intends to develop a new preparation method to improve the technical defects of the above preparation modes by using the wet laying method to prepare composite mycelium leather-like materials. Summary of the Invention

[0004] The purpose of the present invention is to provide a composite mycelium leather-like material and a preparation method thereof to solve the problems existing in the above-mentioned prior art. This preparation method has advantages such as high production efficiency, easy scale-up, simple operation, and short production cycle. The composite mycelium leather-like material prepared by using the preparation method of the present invention has good mechanical properties, including high tensile strength, tear strength, and flexibility, etc., and can fully meet the requirements of leather-like products.

[0005] To achieve the above purpose, the present invention provides the following solution:

[0006] The present invention provides a preparation method of a composite mycelium leather-like material, comprising the following steps:

[0007] Homogenize the mycelium to form mycelium slurry, then mix the mycelium slurry with a modified polyvinyl alcohol solution to obtain a mixture, add glycerol, stir evenly, pour it into a mold after removing air bubbles, and after low-temperature treatment and drying treatment, peel the mycelium material from the mold to obtain the mycelium leather-like material;

[0008] The mycelium is the mycelium of a fungus of the family Polyporaceae.

[0009] Furthermore, the preparation method of the modified polyvinyl alcohol solution comprises the following steps:

[0010] Dissolve polyvinyl alcohol in water, add boric acid solution or citric acid solution under stirring, and then add maleic anhydride solution under stirring, and stir evenly to obtain the modified polyvinyl alcohol solution.

[0011] Furthermore, the dry weight of the mycelium in the mycelium pulp is 2 wt%.

[0012] Furthermore, the mass ratio of the mycelium pulp to the modified polyvinyl alcohol solution is 5:2.

[0013] Furthermore, the mass ratio of the glycerol to the mixture is 1:50.

[0014] Furthermore, the low-temperature treatment is refrigeration at 2 - 4 °C for 72 h.

[0015] Furthermore, the mycelium is obtained by fermentation culture using an MEB medium;

[0016] The MEB medium comprises 20 g / L of malt extract powder and 2 g / L of soy peptone.

[0017] Furthermore, the culture temperature for the fermentation culture is 25 - 32 °C, the initial pH of the medium is 4.5 - 6.5, the rotation speed is 110 - 170 rpm, the inoculation rate is 3% - 25%, and the culture time is 2 - 6 days.

[0018] The present invention also provides a composite mycelium leather-like material prepared by the above preparation method.

[0019] The present invention also provides the application of the above composite mycelium leather-like material in the preparation of leather-like products.

[0020] The present invention discloses the following technical effects:

[0021] The present invention develops a new preparation method for a composite mycelium leather-like material, and uses the wet laying method to prepare the composite mycelium leather-like material. This preparation method has advantages such as high production efficiency, easy scale-up, simple operation, and short production cycle.

[0022] The composite mycelium leather-like material prepared by the preparation method of the present invention has good mechanical properties, including high tensile strength, tear strength, flexibility, etc., and can fully meet the requirements of leather-like products. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0024] Figure 1 Statistical chart of mycelium yield at different culture temperatures;

[0025] Figure 2 Statistical chart of mycelium yield and final pH at different initial pH values of the culture medium;

[0026] Figure 3 Statistical chart of mycelium yield at different shaker speeds;

[0027] Figure 4 Statistical chart of mycelium yield at different inoculation rates;

[0028] Figure 5 Statistical chart of mycelium yield and final pH at different culture times;

[0029] Figure 6 Comparison chart of mycelium leather-like materials at different dry basis contents of mycelium pulp;

[0030] Figure 7 Comparison chart of samples of mycelium leather-like materials prepared by different preparation methods. Detailed implementation manners

[0031] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0032] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0033] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0034] Without departing from the scope or spirit of this invention, various improvements and changes can be made to the specific embodiments of the specification of this invention, which will be obvious to those skilled in the art. Other embodiments obtained from the specification of this invention will be obvious to those skilled in the art. The specification and examples of this invention are merely exemplary.

[0035] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0036] The experimental materials and equipment used in the following examples are as follows:

[0037] 1. Strains: Ganoderma lucidum from South Korea is used as the experimental strain (fungi such as Coriolus versicolor and Ganoderma lucidum in the family Polyporaceae can all be applicable to the method of this invention).

[0038] 2. Reagents and materials: Reagents and materials: Glucose, malt extract powder, soy peptone, corn steep liquor, agar, yeast extract powder, CaCO3, glutaraldehyde (25%), tannin, glycerol, boric acid, maleic anhydride, polyvinyl alcohol (degree of polymerization 1799), chitosan (degree of deacetylation > 90%), genipin (purity 95%), citric acid, etc. are all biochemical reagents or analytical pure. Potatoes are commercially available.

[0039] 3. Equipment and instruments: Equipment such as a homogenizer, drying oven, shaking incubator, biochemical incubator, high-pressure steam sterilizer, and laminar flow hood, and instruments such as a flat-bottom shallow dish (paper-plastic), stainless steel filter sieve, 500 mL Erlenmeyer flask, 250 mL Erlenmeyer flask, 2 L Erlenmeyer flask, and beaker.

[0040] 4. Culture media:

[0041] PDA medium: 200 g / L of potatoes, 20 g / L of glucose, 14 g / L of agar, pH natural.

[0042] PDB enriched medium: 300 g / L of potatoes, 20 g / L of glucose, 2 g / L of corn steep liquor, pH natural.

[0043] MEA medium: 20 g / L of malt extract powder, 2 g / L of soy peptone, 14 g / L of agar, pH natural.

[0044] MEB medium: 20 g / L of malt extract powder, 2 g / L of soy peptone, natural pH.

[0045] Ⅱ5 medium: 1.8 g / L of CaCO3, 70 g / L of brown sugar, 50 g / L of cane molasses, 4.8 g / L of yeast extract powder, 10.4 g / L of corn steep liquor, 3.8 g / L of safflower seed oil, initial pH 6.5.

[0046] Fermentation medium: 20 g / L of malt extract powder, 3 g / L of soy peptone, pH 6.0.

[0047] The above media were all sterilized at 121 °C for 20 min.

[0048] Example 1

[0049] 1. Experimental method

[0050] 1.1 Activation of fungal strains: Take out the Ganoderma lucidum strains from the refrigerator, place them at room temperature to recover for more than 6 h, cut a small piece of the mycelium block in a sterile environment, inoculate it into the PDA medium, and seal it with a sealing film. Then place it in a biochemical incubator at 25 °C for dark cultivation for 7 days.

[0051] 1.2 Preparation of Ganoderma lucidum spore suspension: Cut off a small piece of the mycelium tip of the activated Ganoderma lucidum strains and transfer it to the MEA medium, and cultivate it in a biochemical incubator at 25 °C for dark cultivation for 7 days. Under sterile conditions, pipette 10 mL of sterile water onto the MEA plate covered with mycelium, gently scrape the mycelium layer with a glass spreader, and collect the spore suspension with a pipettor.

[0052] 1.3 Preparation of Ganoderma lucidum seed liquid: Inoculate the Ganoderma lucidum spore suspension into the MEB medium at an inoculation rate of 2.5%-5%, and shake-culture it at 25 °C and 130 rpm for 3 days. Under sterile conditions, collect the mycelial pellets, homogenize them at a speed of 5000 revolutions per second for 20 seconds, and then add sterile water or MEB medium to form a spore suspension, and adjust the mycelium content in the spore suspension to more than 20% (m / v), and store it in the refrigerator for later use.

[0053] 1.4 Selection of media: Inoculate the Ganoderma lucidum seed liquid into 500 mL Erlenmeyer flasks containing 200 mL of different types of liquid media at an inoculation rate of 2.5%. The media are PDB, enriched PDB, MEB, and Ⅱ5 respectively. Place them on a shaker at 25 °C and 130 rpm for constant-temperature shaking culture for 8 days. Filter the mycelial pellets, wash them three times, dry them to a constant weight in an oven at 70 °C, and then weigh them to calculate the dry basis content.

[0054] 1.5 Optimization of culture conditions

[0055] Fermentation temperature, initial pH of the medium, shaker speed, inoculation rate, and culture time all affect the fermentation yield of Ganoderma lucidum mycelium. In the experiment, MEB was used as the fermentation medium, and Ganoderma lucidum seed liquid was inoculated. The fermentation temperature gradients were set at 24°C, 28°C, 32°C, and 36°C, the inoculation rate was 2.5%, the pH of the medium was natural, and the culture was carried out at a constant temperature of 130 rpm for 8 days; the initial pH value gradients of the fermentation medium were set at 4.5, 5, 5.5, 6, and 6.5, the inoculation rate was 2.5%, and the culture was carried out at a constant temperature of 25°C and 130 rpm for 8 days; the shaker speed gradients were set at 110 rpm, 130 rpm, 150 rpm, and 170 rpm, the inoculation rate was 2.5%, and the culture was carried out at a constant temperature of 25°C for 8 days; the inoculation rate gradients were set at 3%, 6%, 9%, 12%, 20%, and 25%, the pH of the medium was natural, and the culture was carried out at a constant temperature of 25°C and 130 rpm for 8 days; the culture time gradients were set at 2, 4, 6, 8, 10, 12, and 14 days, the inoculation rate was 2.5%, the pH of the medium was natural, and the culture was carried out at a constant temperature of 25°C and 130 rpm. The yield was calculated by measuring the dry basis content of the mycelium in the fermentation broth, and the optimal conditions were selected.

[0056] 1.6 Analytical method

[0057] Determination of the dry basis content of mycelium: Take 100 mL of fermentation broth, filter the mycelium, wash it 3 times with distilled water, dry it to a constant weight at 80°C, and weigh it on an electronic balance, which is the dry basis content of the mycelium in every 100 mL.

[0058] 2. Results

[0059] 2.1 Selection of fermentation medium

[0060] As is well known, the composition of the medium affects the mycelium morphology and the yield of mycelium biomass in liquid submerged fermentation. The candidate media in this experiment were PDB, enriched PDB, MEB, and Ⅱ5, and the experimental results are shown in Table 1.

[0061] Table 1 Selection of fermentation medium

[0062]

[0063] The results showed that the highest mycelium yield was obtained with medium Ⅱ5, followed by MEB medium and enriched PDB medium, and the lowest yield was with PDB medium. Among them, the mycelial pellets in PDB and enriched PDB media were relatively dense and small in size; the mycelial pellets in MEB and Ⅱ5 media were relatively loose. Among them, the mycelial pellets in Ⅱ5 medium were large in size and uneven, the fermentation broth was viscous and difficult to filter, and the mycelium was dark red due to the presence of impurities in the medium. The results indicated that the nutritional composition of the medium affected the formation and shaping of mycelial pellets, and using MEB medium as the fermentation medium could obtain relatively pure mycelial pellets. Therefore, it was the optimal medium for submerged liquid fermentation to produce mycelium.

[0064] 2.2 Optimization of fermentation conditions

[0065] In addition to the significant impact of nutritional components on mycelium yield, fermentation conditions such as temperature, initial pH value, shaker speed, inoculation rate, and culture time also affected the yield of mycelium biomass and the formation of mycelial pellets. In the experiment, single-factor experiments were conducted on conditions such as fermentation temperature, initial pH value of the medium, shaker speed, inoculation rate, and culture time.

[0066] 2.2.1 Selection of culture temperature

[0067] The results showed that the mycelium biomass increased with the increase of culture temperature. When the culture temperature was 32 °C, the mycelium biomass reached 0.58 g / 100 mL and then decreased. This indicated that the increase in temperature could promote the growth of mycelium, and the optimal culture temperature was 32 °C ( Figure 1 ).

[0068] 2.2.2 Selection of initial pH of the medium

[0069] The results showed that with the increase of the initial pH of the medium, both the mycelium biomass and the final pH value of the fermentation broth showed a trend of first increasing and then decreasing. When the initial pH of the medium was 5, the dry basis content of Ganoderma lucidum mycelium biomass reached the maximum value of 0.64 g / 100 mL. At this time, the final pH of the fermentation broth was 5.11, while when the initial pH of the medium was 5.5, the final pH of the fermentation broth decreased to 5.18 ( Figure 2 ). It was shown that the optimal initial pH of the medium was 5.

[0070] 2.2.3 Selection of shaker speed

[0071] The results showed that with the increase of the shaker speed, the mycelial biomass increased. When the shaker speed increased to 130 rpm, the dry basis content of the mycelial biomass reached 0.6 g / 100 mL, and then the mycelial biomass decreased with the further increase of the speed. This indicated that increasing the shaker speed could increase the dissolved oxygen rate and promote the growth of the mycelium. However, with the further increase of the speed, the mycelial pellets became denser, affecting the diffusion of oxygen in the liquid environment into the interior of the pellets, resulting in a decrease in the mycelial productivity. Figure 3 ) It was shown that the optimal shaker speed was 130 rpm.

[0072] 2.2.4 Selection of inoculation rate

[0073] The results showed that with the increase of the inoculation rate, the mycelial biomass also increased. When the inoculation rate was 15%, the dry basis content of the Ganoderma lucidum mycelial biomass reached the maximum value of 2.54 g / 100 mL. When the inoculation rate was higher than 15%, the mycelial biomass decreased instead, indicating that the optimal inoculation rate was 15%. Figure 4 )

[0074] 2.2.5 Selection of culture time

[0075] The results showed that with the extension of the culture time, the yield of the mycelial biomass increased. When cultured for 6 days, the mycelial yield reached 0.65 g / 100 mL, and then the mycelial yield showed a downward trend with the further extension of the culture time. Figure 5 )

[0076] Example 2

[0077] 1. Experimental method

[0078] 1.1 Preparation of Ganoderma lucidum mycelium

[0079] Absorb 5 mL of Ganoderma lucidum spore suspension and inoculate it into a 250 mL Erlenmeyer flask containing 100 mL of MEB medium. Place it in an oscillating incubator and culture it under the conditions of 25 °C and 130 rpm for 3 days. Then inoculate it into a 2 L Erlenmeyer flask containing 800 mL of MEB medium and culture it at a constant temperature of 25 °C and 130 rpm for 8 days. Filter to obtain the mycelium, and wash it three times with water for standby.

[0080] 1.2 Analysis method

[0081] Tensile strength measurement: Cut at least 5 dog-bone-shaped samples from each piece of mycelial leather-like material. Use an electronic caliper to measure the thickness of each sample at 3 random positions. Tensile measurement was carried out on a Shimadzu EZ-LX single-column electronic universal testing machine under RT conditions with a displacement of 50 mm / min. The ultimate tensile strength (σ) was obtained by dividing the maximum force (N) of each sample by the cross-sectional area (mm 2)It is obtained. The elongation at break (ε) is calculated as a percentage of the gauge length before and after testing.

[0082] TGA determination: Thermogravimetric analysis (TGA) was carried out using a thermal analysis system. Under a constant nitrogen flow, 7 - 15 mg of mycelium powder was subjected to a temperature scan from 25 - 700 °C at a rate of 10 °C / min.

[0083] 1.3 Using Ganoderma lucidum mycelium pulp from South Korea as the main raw material, the mycelium leather-like material was prepared by the wet laying method. The effects of the dry basis content of the mycelium, the addition amount of the PVA modified solution, the addition amount of glycerol, low-temperature treatment, etc. on the surface properties and mechanical properties of the mycelium leather-like material were mainly investigated in order to obtain the optimal process conditions.

[0084] Preparation of the mycelium leather-like material:

[0085] Preparation of the modified PVA solution: Dissolve 10 g of polyvinyl alcohol (PVA) in 100 mL of ultrapure water. After heating and completely dissolving, slowly add boric acid (citric acid can also be used for modification) under stirring, stir for 1 min while adding, and then slowly add maleic anhydride, stirring evenly while adding to obtain the modified PVA solution for standby. Among them, the addition amounts of boric acid and maleic anhydride are 1% (m / v) and 1.5% (m / v) of the PVA solution respectively.

[0086] Preparation of the mycelium leather-like material by the wet laying method: Filter the washed mycelium by suction, homogenize to form mycelium pulp, adjust the dry weight of the mycelium in the mycelium pulp to 1 - 4 wt%, then mix 100 g of mycelium pulp with 10 - 50 g of the modified PVA solution, add 1.5 - 3.5 wt% glycerol during stirring, stir evenly, pour it into a shallow flat dish after the bubbles are eliminated, after low-temperature treatment, put it into a drying oven at 60 °C and dry for more than 8 h, then take it out, peel the mycelium material from the shallow dish, which is the mycelium leather-like material.

[0087] 2. Results

[0088] 2.1 Effect of the dry basis content of the mycelium pulp on the mycelium leather-like material

[0089] The content of the mycelium in the mycelium pulp may have a certain influence on the surface roughness and flexibility of the mycelium material. In the experiment, the dry basis content of the mycelium pulp was set at 4 gradients of 1 wt%, 2 wt%, 3 wt% and 4 wt%, the addition amount was 100 g, the addition amount of the modified PVA solution was 40 g, glycerol was added according to 2 wt% of the mixture weight, the laying thickness was 1 cm, it was placed in the refrigerator at 2 - 4 °C and refrigerated for 72 h, taken out and thawed at room temperature and then dried at 60 °C for 12 h. Three parallels were made for each gradient, and the average value was calculated. The results are as Figure 6 and shown in Table 2.

[0090] Table 2 Influence of the dry basis content of mycelium pulp on mycelium leather-like materials

[0091]

[0092] The results show that with the increase of the dry basis content of mycelium pulp, the thickness of the material samples increases, and the softness decreases. When the dry basis content of mycelium pulp is 2 wt%, the tensile strength of the obtained mycelium material is 18.84 MPa, the softness is moderate, and the surface of the material is flat and smooth. When the dry basis content ≥ 3 wt%, the softness and strength of the obtained material also decrease, and the surface of the formed material is rough and hard. The results indicate that when the dry basis content of mycelium pulp is 2 wt%, the various properties of the obtained mycelium leather-like material are optimal.

[0093] 2.2 Influence of the addition amount of modified PVA solution on the mechanical properties of mycelium leather-like materials

[0094] In the experiment, the addition amounts of the modified PVA solution were set as 10 g, 20 g, 30 g, 40 g and 50 g, 100 g of mycelium pulp (2 wt%), and glycerol was added according to 2 wt% of the total weight. The above mixture was placed on an electric stirrer and stirred at 450 rpm for 30 min. After the bubbles in the mixed solution were eliminated, it was injected into a 10 cm × 10 cm flat plate with a thickness of 1 cm, placed in a refrigerator at 2 - 4 °C for 72 h, taken out and thawed at room temperature, and then dried at 60 °C for 12 h. The cured mycelium sheet was taken out for tensile testing and appearance evaluation, and the results are shown in Table 3.

[0095] Table 3 Influence of the addition amount of modified PVA solution on the mechanical properties of mycelium leather-like materials

[0096]

[0097]

[0098] The results show that with the increase of the addition amount of the PVA modified solution, the tensile strength of the mycelium material increases, the strain at the breaking point decreases, and the softness of the mycelium material decreases. When the addition amount of the PVA modified solution is 40 g, the flexibility and softness of the mycelium material are both good. The results indicate that the tensile strength of the mycelium leather-like material increases with the increase of the addition amount of the PVA modified solution, and the optimal addition amount of the PVA modified solution is 40 g.

[0099] 2.3 Influence of the addition amount of glycerol on the mechanical properties of mycelium leather-like materials

[0100] The addition amount of glycerol affects the apparent state and mechanical properties of the mycelium leather-like material. In the experiment, the addition amount of the modified PVA solution was set to 40 g, the mycelium pulp (2 wt%) was 100 g, and the addition amounts of glycerol were set to 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt% and 3.5 wt% of the mass of the mixture. The above mixture was placed on an electric stirrer and stirred at 450 rpm for 30 min. After the bubbles in the mixed solution were eliminated, it was injected into a 10 cm × 10 cm flat plate with a thickness of 1 cm, placed in a refrigerator at 2-4 °C for refrigeration for 72 h, taken out and thawed at room temperature, and then dried at 60 °C for 12 h, and tensile tests and apparent evaluations were carried out. The results are shown in Table 4 below.

[0101] Table 4 Effects of Glycerol Addition Amount on Mycelium Leather-like Material

[0102]

[0103] The results show that with the increase of the addition amount of glycerol, the tensile strength of the mycelium material increases, but the increase amplitude is small, and the strain at the break point also increases. When the addition amount of glycerol ≥ 3.5 wt%, the increase amplitude of the strain at the break point of the mycelium material is small. When the addition amount of glycerol ≤ 2.5 wt%, the surface of the mycelium material is dry. When the addition amount of glycerol ≥ 2.5 wt%, the surface of the mycelium material is wet or has a large amount of accumulated liquid, and the surface is sticky. It shows that the optimal addition amount of glycerol is 2 wt% of the mass of the mixture.

[0104] 2.4 Effects of Low-temperature Treatment on Mechanical Properties of Mycelium Leather-like Material

[0105] When the mycelium pulp changes the environmental conditions of temperature and pH value, the interaction between its components changes, thus forming a network structure. For example, when the temperature decreases, the hydrogen bond interaction between polysaccharide molecules in the mycelium pulp is enhanced, fixing small molecules such as water in it, thus forming a gel. It is also possible to add a cross-linking agent to form chemical bonds such as covalent bonds or ionic bonds with the components in the mycelium pulp, thus constructing the network structure of the gel. In the experiment, the addition amount of the modified PVA solution was set to 40 g, the mycelium pulp (2 wt%) was 100 g, and the addition amount of glycerol was set to 2 wt% of the mass of the mixture. The evenly stirred mycelium pulp-modified PVA mixture was injected into a flat plate with a thickness of 1 cm, and a layer of plastic film was laid on the surface, and then placed in a refrigerator at 2-4 °C for refrigeration for 72 h and frozen at -20 °C for 6 h respectively. After taking out and thawing at room temperature, it was dried at 60 °C for 12 h, and then naturally dried at room temperature, and tensile tests were carried out. The results are shown in Table 5.

[0106] Table 5 Effects of Low-temperature Treatment on Mechanical Properties of Mycelium Leather-like Material

[0107]

[0108] The results showed that after the mycelium pulp and the modified PVA mixture were refrigerated in a refrigerator at 2 - 4°C for 72 h, they showed a typical gel state, while after being frozen at -20°C for 12 h, they presented a honeycomb shape. After drying, the surface of the leather-like material treated by refrigeration was relatively smooth, while the surface of the leather-like material treated by freezing was rougher and had larger voids.

[0109] Example 3

[0110] Preparation of the mycelium leather-like material:

[0111] (1) Preparation of the modified PVA solution: Dissolve 10 g of polyvinyl alcohol (PVA) in 100 mL of ultrapure water. After heating to completely dissolve, slowly add a 1.5% boric acid solution (citric acid solution can also be used for modification) under stirring, stir for 1 min while adding, and then slowly add a 1% maleic anhydride solution, stir evenly while adding to obtain the modified PVA solution, and set aside.

[0112] (2) Preparation of the mycelium leather-like material by the wet laying method: Filter the washed Ganoderma lucidum mycelium (prepared according to the method of Example 2), homogenize to form mycelium pulp, adjust the dry weight of the mycelium in the mycelium pulp to 2 wt%, then mix 100 g of mycelium pulp with 40 g of the modified PVA solution, add 2.8 g of glycerol during stirring, stir evenly, pour it into a flat shallow dish after the bubbles are eliminated, refrigerate in a refrigerator at 2 - 4°C for 72 h, then put it into a drying oven at 60°C and dry for more than 8 h, then take it out, peel the mycelium material from the shallow dish, which is the mycelium leather-like material. After coating, dyeing, embossing and other treatments on the mycelium leather material, the mycelium leather-like material can be obtained.

[0113] Comparative Example 1

[0114] (1) Preparation of the PVA solution: Dissolve 10 g of polyvinyl alcohol (PVA) in 100 mL of ultrapure water. After heating to completely dissolve, obtain the PVA solution and set aside.

[0115] (2) Preparation of the mycelium leather-like material by the wet laying method: Filter the washed Ganoderma lucidum mycelium (prepared according to the method of Example 2), homogenize to form mycelium pulp, adjust the dry weight of the mycelium in the mycelium pulp to 2 wt%, then mix 100 g of mycelium pulp with 40 g of the PVA solution, add 2.8 g of glycerol during stirring, stir evenly, pour it into a flat shallow dish after the bubbles are eliminated, refrigerate in a refrigerator at 2 - 4°C for 72 h, then put it into a drying oven at 60°C and dry for more than 8 h, then take it out, peel the mycelium material from the shallow dish, which is the mycelium leather-like material.

[0116] Comparative Example 2

[0117] The washed Ganoderma lucidum mycelium (same as in Example 3) was filtered by suction, homogenized to form a mycelium slurry, and the dry weight of the mycelium in the mycelium slurry was adjusted to 2 wt%. Then, 100 g of the mycelium slurry was mixed evenly with 100 g of a 2 wt% chitosan solution (dissolved in a 1% acetic acid solution by volume) and 4 g of glycerol. Then, genipin as a crosslinking agent was added in a ratio of 1 wt% based on the total amount of the dry weight of the mycelium and chitosan, and the mixture was stirred on a stirrer at 400 rpm for 30 min. When there were no bubbles, it was poured into a shallow flat dish and dried in an oven at 40 °C for 24 h. Then, it was taken out and air-dried naturally, and the mycelium material was peeled off from the shallow dish.

[0118] Comparative Example 3

[0119] The washed Ganoderma lucidum mycelium (same as in Example 3) was filtered by suction, homogenized to form a mycelium slurry, and the dry weight of the mycelium in the mycelium slurry was adjusted to 2 wt%. Then, 100 g of the mycelium slurry was mixed evenly with 2 g of glycerol, poured into a shallow flat dish, and refrigerated in a refrigerator at 2 - 4 °C for 1 week. Then, the gelled mycelium pad was taken out, drained of water, and crosslinked and cured with a 5% tannin solution for 24 h, during which the sample needed to be turned over. Then, the crosslinking agent solution was removed, and the sample was taken out after drying at 60 °C for 5 h and air-dried naturally at room temperature.

[0120] Comparative Example 4

[0121] The washed Ganoderma lucidum mycelium (same as in Example 3) was filtered by suction, homogenized to form a mycelium slurry, and the dry weight of the mycelium in the mycelium slurry was adjusted to 2 wt%. 100 g of the mycelium slurry was taken, then 1 g of citric acid and 2 g of glycerol were added, stirred evenly, then poured into a shallow flat dish, taken out after drying in an oven at 80 °C for 6 h, air-dried naturally at room temperature, peeled off from the shallow dish, and then soaked in a 2% citric acid solution for 24 h, and taken out and air-dried naturally.

[0122] Comparative Example 5

[0123] The washed mycelium (same as in Example 3) was filtered by suction, homogenized to form a mycelium slurry, and the dry weight of the mycelium in the mycelium slurry was adjusted to 2 wt%. It was filtered by suction to form a mycelium cake, and after drying, the mycelium sheet was peeled off from the filter net, and then immersed in a 1.5% glutaraldehyde solution (pH = 4 - 4.5) by volume for more than 12 h. Then, the sample was taken out, rinsed, immersed in a 10% glycerol solution by volume, and taken out and air-dried naturally after 12 h.

[0124] The methods of Example 3 and Comparative Examples 1 - 5 were used to prepare mycelium leather-like materials from the mycelium slurry, and the elastic modulus, flexibility, and material appearance were detected. The results are shown in Figure 7 and Table 6.

[0125] Table 6 Comparison table of preparation methods of several mycelium leather-like materials

[0126]

[0127] The results show that the tensile strength of the mycelium leather-like material obtained in Example 3 is the highest, which is 18.64 MPa, and the flexibility is also the best. There are leather textures on the front side (the upward side) of the material. The results indicate that the mycelium composite material prepared by the method of the present invention has good application potential.

[0128] The above-described embodiments are only descriptions of the preferred modes of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing a composite mycelium imitation leather material, characterized in that: The following steps are involved: The mycelium is homogenized to form a mycelium slurry, and then the mycelium slurry is mixed with a modified polyvinyl alcohol solution to obtain a mixture, and then glycerin is added, stirred evenly, and poured into a mold after bubbles are eliminated, and after low-temperature treatment and drying treatment, the mycelium material is peeled off from the mold to obtain the mycelium imitation leather material; The mycelium is the mycelium of the Polyporaceae fungus.

2. The preparation method according to claim 1, characterized in that: The preparation method of the modified polyvinyl alcohol solution comprises the following steps: The polyvinyl alcohol is dissolved in water, and a boric acid solution or a citric acid solution is added under stirring, and then a maleic anhydride solution is added under stirring, and stirred evenly to obtain the modified polyvinyl alcohol solution.

3. The preparation method according to claim 1, characterized in that: The dry weight of mycelium in the mycelium slurry is 2 wt %.

4. The preparation method according to claim 1, characterized in that: The mass ratio of the mycelium slurry to the modified polyvinyl alcohol solution is 5:

2.

5. The preparation method according to claim 1, characterized in that: The mass ratio of the glycerol to the mixture is 1:

50.

6. The preparation method according to claim 1, characterized in that: The low temperature treatment is refrigeration at 2-4°C for 72 hours.

7. The preparation method according to claim 1, characterized in that: The mycelium is obtained by fermentation culture using MEB medium; The MEB culture medium comprises 20 g / L malt extract powder and 2 g / L soy peptone.

8. The preparation method according to claim 7, characterized in that: The culture temperature of the fermentation culture is 25-32° C., the initial pH of the culture medium is 4.5-6.5, the rotation speed is 110-170 rpm, the inoculation rate is 3%-25%, and the culture time is 2-6 days.

9. A composite mycelium imitation leather material prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the composite mycelium imitation leather material according to claim 9 in the preparation of imitation leather products.

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