A lightweight bio-based cushioning material and preparation method thereof

Abstract

The present invention discloses a lightweight bio-based buffer material and a preparation method thereof. The lightweight bio-based buffer material is obtained by filling a mold and fermenting after mixing the seed liquid of edible fungi and the seed liquid of bacterial cellulose. The apparent density of the lightweight bio-based buffer material is 0.1-0.25 g / cm<supgt;3< / supgt>, and the compressive strength is 0.15-0.45 MPa. After mixed bacteria fermentation in the present invention, due to the gel-like state of bacterial cellulose itself, it can wind and wrap the solid matrix and edible fungi hyphae more densely, forming a three-dimensional network structure, effectively improving the internal binding force of the material.

Description

Technical Field

[0001] The present invention relates to the field of bio-based materials, and in particular to a lightweight bio-based buffer material and a preparation method thereof. Background Art

[0002] At present, various microplastics produced by excessive use and incorrect disposal of non-degradable synthetic plastics pose a serious threat to human health and natural ecosystems. Microplastics can shift and accumulate in human tissues, causing inflammation and blockage of organs. At the same time, they can exist in nature for more than 100 years or even hundreds of years, causing profound impacts on freshwater and terrestrial environments. Taking foaming materials such as polystyrene (PS) as an example, as a widely used plastic, the annual output can reach 1.527 million tons, with a market size of 14.09 billion yuan, which is an important source of plastic pollution. At the same time, the annual consumption of plastic waste, including express packaging bags or lunch boxes, is nearly 10 million tons. The annual output of disposable plastic products alone in the world reaches 120 million tons, of which more than 70% are discarded into the soil, air and ocean.

[0003] Therefore, the development of degradable plastics has become an inevitable demand for social development. Compared with traditional plastics, bio-based degradable materials have significant advantages. As a new type of degradable bio-based material, straw mycelium material has many advantages, such as integrated microbial cultivation and molding, a wide range of straw matrix sources, and no need to add toxic chemical adhesives. At present, the technology on mycelium materials is mainly reported on preparation and molding technology, and some problems caused by the practical application of this material have not been solved, such as the low mechanical properties of the material and difficulty in reducing the density.

[0004] Bacterial cellulose is a natural nanocellulose synthesized by microorganisms. It is a biological type material with high stiffness, tensile strength, low density, high purity, biodegradability and easy operation. However, there is still little development in the direction of its utilization. Therefore, the present invention provides a lightweight bio-based cushioning material and a preparation method thereof. Summary of the invention

[0005] Purpose of the invention: The technical problem to be solved by the present invention is to provide a lightweight bio-based cushioning material in view of the deficiencies in the prior art.

[0006] Another technical problem to be solved by the present invention is to provide a method for preparing the above-mentioned lightweight bio-based buffer material.

[0007] In order to solve the first technical problem mentioned above, the present invention discloses a lightweight bio-based buffer material, which is obtained by mixing edible fungus seed liquid and bacterial cellulose seed liquid and then filling molds and fermenting them.

[0008] In some embodiments, the apparent density of the lightweight bio-based cushioning material is 0.1 to 0.25 g / cm 3 , preferably 0.1 to 0.2 g / cm 3 , preferably 0.1 to 0.15 g / cm 3 .

[0009] In some embodiments, the compressive strength of the lightweight bio-based cushioning material is 0.15 to 0.45 MPa, preferably 0.3 to 0.45 MPa, and preferably 0.4 to 0.45 MPa.

[0010] In order to solve the above-mentioned second technical problem, the present invention discloses a method for preparing the above-mentioned lightweight bio-based buffer material, which comprises mixing the seed liquid of edible fungi with the seed liquid of bacterial cellulose and then filling a mold and fermenting; in some embodiments, the method for preparing the lightweight bio-based buffer material is to mix the seed liquid of edible fungi with the seed liquid of bacterial cellulose, inoculate it on a solid matrix, fill a mold, perform solid-state fermentation, demold, and dry and dehydrate to obtain the lightweight bio-based buffer material.

[0011] In some embodiments, the edible fungus is any one or a combination of Ganoderma lucidum, Pleurotus ostreatus, Flammulina velutipes, Pleurotus eryngii and Volvariella volvacea, preferably Ganoderma lucidum and / or Pleurotus ostreatus, preferably Ganoderma lucidum; Ganoderma lucidum, Pleurotus ostreatus, Flammulina velutipes, Pleurotus eryngii and Volvariella volvacea in the prior art are all suitable for the present invention, not limited to specific strains.

[0012] In some embodiments, the preparation method of the edible fungus seed liquid is to inoculate the edible fungus into the edible fungus seed liquid culture medium for fermentation; in some embodiments, the composition of the edible fungus seed liquid culture medium is as follows: nitrogen source 0.5-1.5 g / L, carbon source 10-30 g / L, MgSO 4 0.1~0.9g / L, FeSO 4 7H 2 O 0.06~0.3g / L, KH 2 PO 4 0.08~0.8g / L, VB10.01g / L; in some embodiments, the nitrogen source is amino acid fermentation waste liquid; in some embodiments, the nitrogen source is the waste liquid produced after threonine fermentation; in some embodiments, the nitrogen source is the fermentation liquid obtained after threonine fermentation, which is concentrated and crystallized by membrane, and the remaining liquid is the nitrogen source; in some embodiments, the fermentation temperature is 25~30℃; in some embodiments, the fermentation speed is 120~170rpm; in some embodiments, the fermentation time is 5~7 days.

[0013] In some embodiments, the bacterial cellulose is Acetobacter xylinum, preferably Acetobacter xylinum ATCC 700178.

[0014] In some embodiments, the method for preparing the bacterial cellulose seed solution is to inoculate the bacterial cellulose in a bacterial cellulose seed solution culture medium for fermentation; in some embodiments, the composition of the bacterial cellulose seed culture medium is as follows: 20-30 g / L glucose, 5-15 g / L yeast extract, 5-15 g / L peptone, CaCO 3 0.5~1.5g / L; preferably glucose 25g / L, yeast extract 10g / L, peptone 10g / L, CaCO 3 1g / L; in some embodiments, the fermentation temperature is 25-35°C, preferably 30°C; in some embodiments, the fermentation speed is 120-170rpm, preferably 150rpm; in some embodiments, the fermentation time is 1-3 days.

[0015] In some embodiments, the volume ratio of the edible fungus seed liquid to the bacterial cellulose seed liquid is 2-4:1-3, preferably 3:1-3, preferably 3:2.

[0016] In some embodiments, the solid matrix includes straw, sawdust and bran; in some embodiments, the solid matrix is ​​composed of the following components in mass fractions: 30% to 50% corn straw, 30% to 50% sawdust, 10% to 30% bran, preferably 40% corn straw, 40% sawdust and 20% bran.

[0017] In some embodiments, after the edible fungus seed liquid and the bacterial cellulose seed liquid are mixed, they are inoculated on the solid matrix at a volume ratio of 10% to 30%, preferably 15% to 25%, and preferably 20%.

[0018] In some embodiments, the temperature of the solid-state fermentation is 20-30°C, preferably 25°C; in some embodiments, the time of the solid-state fermentation is 5-9 days, preferably 7 days.

[0019] In some embodiments, the dehydration time is 15 to 25 hours, preferably 18 to 22 hours.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0021] The present invention develops a method for preparing mycelium materials by culturing bacterial cellulose, thereby helping to improve the mechanical properties of the mycelium materials and effectively reducing the material density to meet the requirements of light weight, thus opening up a new direction for the application of bacterial cellulose.

[0022] The present invention adopts the mixed bacteria fermentation process for the mycelium material for the first time, and the two strains of bacteria can effectively grow in coordination without rejection.

[0023] After mixed bacteria fermentation, the present invention can more densely entangle and wrap the solid matrix and edible fungus mycelium due to the gel-like state of the bacterial cellulose itself, forming a three-dimensional network structure, effectively improving the internal bonding force of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0025] Figure 1 Prepare a flow chart for the material.

[0026] Figure 2 This is a diagram of a plate antagonism experiment. DETAILED DESCRIPTION

[0027] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0028] The edible fungi described in the following embodiments (Ganoderma lucidum species (Taishan red ganoderma), Pleurotus ostreatus species (Sufeng No. 2), Pleurotus eryngii (Pleurotus eryngii No. 1) species, Flammulina velutipes species (Xinmei No. 15 Flammulina velutipes) and Volvariella volvacea species (V901)) were purchased from Tianda Edible Fungi Research Institute in July 2022.

[0029] The amino acid fermentation waste liquid described in the following embodiments is provided by Ningxia Yipin Biotechnology Co., Ltd. (the waste liquid produced after threonine fermentation, for the specific preparation method, refer to Chinese invention patent CN102191290B-Threonine fermentation preparation Example 3, the supernatant is concentrated and crystallized through a membrane, and then the remaining liquid is the fermentation tail liquid, which is the amino acid fermentation waste liquid of this application).

[0030] In the following embodiments, the compression performance test is in accordance with the national standard "GB / T 8813-2020" and the apparent density test is in accordance with the national standard "GB / T6343-2009".

[0031] Example 1: Preparation of lightweight bio-based cushioning material

[0032] Two kinds of seed liquid fermentation culture:

[0033] Ganoderma lucidum seed liquid: The purchased Ganoderma lucidum strains were inoculated into the seed liquid medium for fermentation culture. The seed liquid medium formula is as follows: 1.1 g / L of amino acid fermentation waste liquid, 25 g / L of corn starch, MgSO 4 0.4g / L, FeSO 4 7H 2 O 0.1g / L, KH 2 PO 40.1g / L, VB1 0.01g / L, culture at 25℃, 170rpm for about 7 days to obtain a seed solution rich in mycelium.

[0034] Bacterial cellulose seed solution: Acetobacter xylinum ATCC 700178 was inoculated into a seed culture medium, the formula of which was as follows: glucose 20 g / L, yeast extract 2 g / L, peptone 2 g / L, CaCO 3 0.5 g / L, culture at 28°C and 100 r / min for 2 days to obtain bacterial cellulose seed solution.

[0035] Material inoculation preparation: The obtained ganoderma lucidum seed liquid and bacterial cellulose seed liquid are mixed in a volume ratio of 3:2 and inoculated into a solid matrix (sterilized before inoculation: 121°C, 15min) at 20% of the total volume of the solid matrix (including the following weight percentage components: 40% corn stalks, 40% sawdust, 20% bran) in a clean bench, and then filled into a mold after being stirred evenly. The mold is sealed and placed in a 25°C shaker for static culture for 7 days to prepare mycelium material by solid fermentation. After the solid fermentation is completed, the stalk mycelium material that has been shaped and covered with white mycelium on the surface is removed from the mold and placed in a 70°C oven for drying and dehydration for 20 hours, thereby achieving the purpose of inactivating the bacteria inside the matrix and stopping its growth.

[0036] Material properties: The material after treatment was tested for performance. The test results are as follows: Apparent density: 0.12g / cm 3 ; Compression strength: 0.43MPa.

[0037] Example 2: Preparation of lightweight bio-based cushioning material

[0038] Ganoderma lucidum seed liquid: The purchased Ganoderma lucidum strains were inoculated into the seed liquid medium for fermentation culture. The seed liquid medium formula is as follows: 1.1 g / L of amino acid fermentation waste liquid, 25 g / L of corn starch, MgSO 4 0.4g / L, FeSO 4 7H 2 O 0.1g / L, KH 2 PO 4 0.1g / L, VB1 0.01g / L, culture at 25℃, 170rpm for about 7 days to obtain a seed solution rich in mycelium.

[0039] Material inoculation preparation: The seed liquid rich in Ganoderma lucidum hyphae obtained by culture is inoculated into a solid matrix (sterilized before inoculation: 121°C, 15min) according to 20% of the total volume of the solid matrix (including the following weight percentage components: 40% corn stalks, 40% sawdust, 20% bran) in a clean bench, and then filled into a mold after being stirred evenly. The mold is sealed and placed in a 25°C shaker for static culture for 7 days to perform solid-state fermentation to prepare mycelium material. After the solid-state fermentation is completed, the stalk mycelium material that has been shaped and covered with white hyphae on the surface is removed from the mold, and the material is placed in a 70°C oven for drying and dehydration for 20 hours, and the purpose of inactivating the bacteria inside the matrix is ​​achieved at the same time, so that the growth is stopped.

[0040] Material properties: Apparent density: 0.2g / cm 3 ;Compression strength: 0.30MPa.

[0041] Example 3: Preparation of lightweight bio-based cushioning material

[0042] Two kinds of seed liquid fermentation culture:

[0043] Ganoderma lucidum seed liquid: The purchased Ganoderma lucidum strains were inoculated into the seed liquid medium for fermentation culture. The seed liquid medium formula is as follows: 1.1 g / L of amino acid fermentation waste liquid, 25 g / L of corn starch, 0.4 g / L of MgSO4, and 0.5 g / L of FeSO 4 7H 2 O0.1g / L, KH 2 PO4 0.1g / L, VB1 0.01g / L, culture at 25℃, 170rpm for about 7 days to obtain a seed solution rich in mycelium.

[0044] Bacterial cellulose seed solution: Acetobacter xylinum ATCC 700178 was inoculated into a seed culture medium, the formula of which was as follows: glucose 20 g / L, yeast extract 2 g / L, peptone 2 g / L, CaCO 3 0.5g / L, 28℃, 100r / min, culturing for 2 days.

[0045] Material inoculation preparation: The obtained ganoderma lucidum seed liquid and bacterial cellulose seed liquid are mixed in a volume ratio of 4:1 and inoculated into a solid matrix (sterilized before inoculation: 121°C, 15min) at 20% of the total volume of the solid matrix (including the following weight percentage components: 40% corn stalks, 40% sawdust, 20% bran) in a clean bench, and then filled into a mold after being stirred evenly. The mold is sealed and placed in a 25°C shaker for static culture for 7 days to prepare mycelium material by solid fermentation. After the solid fermentation is completed, the stalk mycelium material that has been shaped and covered with white mycelium on the surface is removed from the mold and placed in a 70°C oven for drying and dehydration for 20h, and the purpose of inactivating the bacteria inside the matrix is ​​achieved at the same time, so that it stops growing.

[0046] Material properties: The material after treatment was tested for performance. The test results are as follows: Apparent density: 0.14g / cm 3 ;Compression strength: 0.4MPa.

[0047] Example 4: Preparation of lightweight bio-based cushioning material

[0048] Ganoderma lucidum seed liquid: The purchased Ganoderma lucidum strains were inoculated into the seed liquid medium for fermentation culture. The seed liquid medium formula is as follows: 1.1 g / L of amino acid fermentation waste liquid, 25 g / L of corn starch, MgSO 4 0.4g / L, FeSO 4 7H2O0.1g / L, KH 2 PO 4 0.1g / L, VB1 0.01g / L, culture at 25℃, 170rpm for about 7 days to obtain a seed solution rich in mycelium.

[0049] Bacterial cellulose seed solution: Acetobacter xylinum ATCC 700178 was inoculated into a seed culture medium, the formula of which was as follows: glucose 20 g / L, yeast extract 2 g / L, peptone 2 g / L, CaCO 3 0.5g / L, 28℃, 100r / min, culturing for 2 days.

[0050] Material inoculation preparation: The obtained ganoderma lucidum seed liquid and bacterial cellulose seed liquid are mixed in a volume ratio of 2:3 in a clean bench according to 20% of the total volume of the solid matrix (including the following weight percentage components: corn straw 40%, sawdust 40%, bran 20%) (sterilized before inoculation: 121°C, 15min), stirred evenly and filled into a mold, the mold is sealed and placed in a 25°C shaker for 7 days for solid fermentation to prepare mycelium material. After the solid fermentation is completed, the straw mycelium material that has been shaped and covered with white mycelium on the surface is removed from the mold, and the material is placed in a 70°C oven for drying and dehydration for 20h, and the purpose of inactivating the bacteria inside the matrix is ​​achieved, so that it stops growing.

[0051] Material properties: The material after treatment was tested for performance. The test results are as follows: Apparent density: 0.13g / cm 3 ; Compression strength: 0.35MPa.

[0052] Example 5: Preparation of lightweight bio-based cushioning material

[0053] Same as Example 1, only Ganoderma lucidum was replaced by Pleurotus ostreatus, Pleurotus eryngii, Enoki mushroom and Volvariella volvacea respectively. The properties of the obtained materials are shown in Table 1. The results show that Ganoderma lucidum has the best compatibility.

[0054] Table 1

[0055]

[0056] Example 6: Antagonism Experiment

[0057] 1. Test strains:

[0058] Ganoderma lucidum, Acetobacter xylinum ATCC 700178

[0059] 2. Reagents and consumables

[0060] 500mL PDA solid culture medium, 12 sterile Oxford cups, marker, ruler, 26°C constant temperature incubator

[0061] 3. Seed formula

[0062] Solid medium: PDA, natural pH

[0063] 4. Culture conditions

[0064] Sterilization conditions: 121°C, 15 minutes;

[0065] Culture conditions: 26℃ for 2-7 days.

[0066] 5. Test methods

[0067] Ganoderma lucidum and ATCC 700178 were cut from PDA medium using an Oxford cup (5 mm in diameter), and the colonies were transferred to the two ends of a PDA medium plate (9 cm in diameter) with the colonies facing downwards, with a distance of 5 cm between the colonies. The colonies were cultured at 26°C for 2-7 days, and the colony radius between the colonies was measured. The experiment was repeated 3 times with the colonies inoculated with only one colony as the control.

[0068] 6. Experimental Evaluation

[0069] like Figure 2 As shown, there is no obvious inhibition of the growth of indicator bacteria between colonies, and no phenomenon of mutual growth inhibition such as horizontal septa / inhibition zones (non-intersecting), ridges, overlaps (intersecting) etc. is formed.

[0070] The present invention provides a light bio-based cushioning material and a method for preparing the same. There are many methods and approaches to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A lightweight bio-based cushioning material, It is characterized in that The light bio-based buffer material is obtained by mixing the seed liquid of edible fungi and the seed liquid of bacterial cellulose-producing fungi and then fermenting them in a mold; the edible fungi are Ganoderma lucidum and / or Pleurotus ostreatus; the bacterial cellulose-producing fungi are Acetobacter xylinum; the apparent density of the light bio-based buffer material is 0.1-0.25 g / cm 3 , the compression strength is 0.15~0.45MPa.

2. The lightweight bio-based cushioning material according to claim 1, It is characterized in that The apparent density of the lightweight bio-based buffer material is 0.1 to 0.2 g / cm 3 .

3. The lightweight bio-based cushioning material according to claim 1, It is characterized in that The apparent density of the lightweight bio-based buffer material is 0.1 to 0.15 g / cm 3 .

4. The lightweight bio-based cushioning material according to claim 1, It is characterized in that The compressive strength of the lightweight bio-based buffer material is 0.3 to 0.45 MPa.

5. The lightweight bio-based cushioning material according to claim 1, It is characterized in that The compressive strength of the lightweight bio-based buffer material is 0.4 to 0.45 MPa.

6. The lightweight bio-based cushioning material according to claim 1, It is characterized in that The bacterial cellulose producing bacteria is Acetobacter xylinum ATCC 700178.

7. A method for preparing a lightweight bio-based buffer material according to any one of claims 1 to 6, It is characterized in that The seed liquid of the edible fungus and the seed liquid of the bacterial cellulose-producing fungus are mixed and then filled into a mold for fermentation.

8. The preparation method according to claim 7, It is characterized in that The seed liquid of the edible fungus is mixed with the seed liquid of the bacterial cellulose-producing fungus, and then inoculated into a solid matrix, molded, solid-state fermented, demolded, dried and dehydrated to obtain a lightweight bio-based buffer material.

9. The preparation method according to claim 7, It is characterized in that The method for preparing the edible fungus seed liquid is to inoculate the edible fungus into an edible fungus seed liquid culture medium for fermentation.

10. The preparation method according to claim 7, It is characterized in that The composition of the edible fungus seed liquid culture medium is as follows: 0.5-1.5 g / L nitrogen source, 10-30 g / L carbon source, MgSO 4 0.1~0.9g / L, FeSO 4 7H 2 O 0.06~0.3g / L, KH 2 PO 4 0.08~0.8g / L, VB1 0.01g / L.

11. The preparation method according to claim 9, It is characterized in that The fermentation temperature is 25-30° C.; the fermentation speed is 120-170 rpm; and the fermentation time is 5-7 days.

12. The preparation method according to claim 7, It is characterized in that The method for preparing the seed liquid of the bacterial cellulose-producing bacteria is to inoculate the bacterial cellulose-producing bacteria into a bacterial cellulose seed liquid culture medium for fermentation.

13. The preparation method according to claim 7, It is characterized in that The composition of the bacterial cellulose production bacteria seed culture medium is as follows: 20-30 g / L glucose, 5-15 g / L yeast extract, 5-15 g / L peptone, CaCO 3 0.5~1.5g / L.

14. The preparation method according to claim 12, It is characterized in that The fermentation temperature is 25-35° C., the fermentation speed is 120-170 rpm, and the fermentation time is 1-3 days.

15. The preparation method according to claim 7, It is characterized in that The volume ratio of the seed liquid of the edible fungi to the seed liquid of the bacterial cellulose-producing fungi is 2-4:1-3.

16. The preparation method according to claim 7, It is characterized in that The volume ratio of the seed liquid of the edible fungi to the seed liquid of the bacterial cellulose-producing fungi is 3:1-3.

17. The preparation method according to claim 8, It is characterized in that The solid matrix includes straw, wood chips and bran.

18. The preparation method according to claim 8, It is characterized in that The solid matrix is ​​composed of the following components in mass fractions: 30% to 50% of corn stalks, 30% to 50% of sawdust, and 10% to 30% of bran.

19. The preparation method according to claim 8, It is characterized in that The seed liquid of the edible fungus and the seed liquid of the bacterial cellulose-producing fungus are mixed and then inoculated on a solid matrix at a volume ratio of 10% to 30%.

20. The preparation method according to claim 8, It is characterized in that The seed liquid of the edible fungus and the seed liquid of the bacterial cellulose-producing fungus are mixed and then inoculated on a solid matrix at a volume ratio of 15% to 25%.

21. The preparation method according to claim 8, It is characterized in that The seed liquid of the edible fungus and the seed liquid of the bacterial cellulose-producing fungus are mixed and then inoculated on a solid matrix at a volume ratio of 20%.

22. The preparation method according to claim 8, It is characterized in that The temperature of the solid-state fermentation is 20-30° C., and the time of the solid-state fermentation is 5-9 days.

23. The preparation method according to claim 8, It is characterized in that The temperature of the solid-state fermentation is 25° C., and the time of the solid-state fermentation is 7 days.

24. The preparation method according to claim 8, It is characterized in that The dehydration time is 15 to 25 hours.

25. The preparation method according to claim 8, It is characterized in that The dehydration time is 18 to 22 hours.

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