Bio-fabricated sound-absorbing panel made of mycelium and agricultural waste

Abstract

The present invention relates to a 100% biodegradable and compostable bio-fabricated sound-absorbing panel that takes less time to break down at the end of its useful life. The panel is made of mycelium and agricultural corn and wheat straw stubble recovered from harvesting processes in Chile.

Description

[0001] BIO-FABRICATED ACOUSTIC ABSORBENT PANEL MADE FROM MYCELIUM AND AGRICULTURAL WASTE

[0002] DESCRIPTIVE MEMORANDUM

[0003] Technical field

[0004] The present invention, in general terms, refers to a bio-fabricated acoustic absorbent panel, 100% biodegradable, compostable, the panel is made from mycelium and agricultural stubble of corn and wheat straw, recovered from harvesting processes in Chile.

[0005] Background

[0006] The excessive consumption of scarce resources, such as non-renewable raw materials, and society's dangerous dependence on fossil fuels have driven the need to recover materials from waste (Franklin, 2018). In addition to offering environmental benefits, these innovations signal a shift in our relationship with materials. We are moving from a linear take-make-dispose model to a more cyclical approach in which alternative raw materials are harvested from industrial and domestic waste streams and landfills (Thompson & Yan Ling, 2013).

[0007] Bio-based materials have gained traction in recent decades due to both environmental and economic concerns. The increasing burden of pollution and waste has motivated the scientific and industrial communities to seek bio-based substitutes for fossil fuel-based materials (Pandit et al., 2018). In the coming decades, bio-based materials are expected to complement and gradually replace some petroleum-based materials. Research efforts in this area have yielded a significant level of technical and commercial success for bio-based materials. However, the widespread application of these materials is still challenged by technical limitations and the higher economic costs associated with their production (Mekonnen et al., 2013).

[0008] New products are attempting to replace conventional products that are currently manufactured from mineral and petroleum resources (plastics, glass, and metals). However, bio-based products generally offer different properties than their petrochemical competitors because their compositions are not equivalent. The main problem this competition poses for the development of bio-based materials is that they are constantly compared to traditional plastics, both in terms of production costs and manufacturing capabilities.

[0009] In general, in the materials development process, if materials are not very durable, inexpensive, or malleable, they are quickly discarded (Thompson & Yan Ling, 2013). Despite this, bio-based products can also offer desirable properties that petrochemical products cannot replicate, and finding markets for these properties is key to their commercialization (Waltz, 2008).

[0010] With the need to generate new alternatives and reduce dependence on materials manufactured from fossil fuels, bio-based materials have emerged as an option to conventional materials by replacing these fuels with a source of renewable resources.

[0011] Bio-based materials are materials composed partially or entirely of raw materials of biological origin, or biomass (Waltz, 2008). Strictly following this definition, many common materials such as paper, wood, and leather can fall into this category. Biomass is an essential part of the composition of these materials and is defined as any non-fossil organic matter available in a renewable manner. This includes all biological organisms, living or dead, and their metabolic byproducts that have not been transformed by geological processes into substances such as coal or oil (Curran, 2010). Examples of biomass include forest residues, crops, agricultural stubble, fungi and bacteria, aquatic plants, and some municipal and industrial waste.Therefore, the development of these materials has the potential to reduce the carbon footprint and increase the efficiency of waste management, thereby reducing the economic and environmental pressure caused by conventional waste.

[0012] Bio-based materials are materials synthesized by living organisms such as plants, fungi, and bacteria. Therefore, the regeneration of the raw material source is guaranteed.

[0013] On the other hand, biomass production also depends on finite resources such as land and water, so there is still a need to expand innovation and technology to move towards a sustainable solution. Material production must adapt to a variety of raw materials with less impact on land use, along with the use of renewable electricity in the production process, and integrate production in such a way that multiple products can be manufactured from available raw materials (Silva et al., 2021).

[0014] Fungi often go unnoticed and the critical role they play in ecosystems is not always appreciated. A huge variety of fungal species play a fundamental role in degrading lignocellulosic biomass and recycling carbon; this is why they are also known as natural recyclers.

[0015] The fungal kingdom encompasses both unicellular and multicellular forms. Unicellular forms are known as yeasts. Multicellular fungi colonize substrates by means of chitinous filaments called hyphae. These hyphae can range in length from millimeters to centimeters. As they grow at their tips and branch, they form a three-dimensional network of hyphae (Blackwell, 2011). The structure and strength of the hyphae are provided by the chitin in their cell walls.

[0016] Chitin is a tough, inelastic, linear polymer linked by hydrogen bonds, which gives it rigidity along its chain. This linkage allows chitin to possess superior tensile strength, even greater than that of carbon fiber and steel (Appels & Wósten, 2021). Chitin is not only an important component of fungal cell walls but also the main constituent of the exoskeletons of crustaceans and insects. As such, it is the second most produced biopolymer in nature after cellulose (Appels & Wósten, 2021).

[0017] The network of hyphae is called mycelium. Mycelium is generally not visible because it grows below the surface, for example, in soil or on tree trunks, growing slowly and continuously as long as environmental and nutritional conditions are suitable.

[0018] The fungal mycelium is a complex network of fibrous cell chains called mycelium, microscopic in size and intertwined in a tube shape, which form the body part of the fungi.

[0019] The shape of the mycelium is due to the fact that fungi feed on dead organic matter, so they try to maximize their surface area in contact with their environment, which explains their dense and branched shape, which to better illustrate we can say resembles the blood capillaries that irrigate our body, or the roots of plants.

[0020] In the last decade, mycelium and its potential have sparked the interest of researchers and companies who see this material as a viable and environmentally sustainable candidate with a wide variety of applications.

[0021] The market for acoustic conditioning materials is currently dominated by foam-type plastic materials such as polyurethane and expanded polystyrene, and synthetics such as fiberglass.

[0022] These materials are manufactured using highly polluting processes, with high energy consumption and the release of toxic gases. Some of them also contain highly questionable synthetic adhesives due to their toxicity, flammability, and harmful health effects.

[0023] These products, at the end of their useful life, become difficult-to-dispose of waste because they lack a natural degradation process that would allow their reintegration into the ecosystem. Recycling these materials requires significant investment, so they mostly end up in landfills or are incinerated, generating serious environmental consequences.

[0024] The process of manufacturing mycelium structures is based on creating an environment conducive to fungal proliferation within a substrate of sterilized organic matter. The mycelium is inoculated into this substrate to grow until adequate colonization is achieved. At this point, a dehydration drying treatment inactivates the mycelium by removing the water present in the material, inhibiting fungal growth and preventing contamination of the samples.

[0025] Among the known disadvantages of managing crop residues, it is estimated that cereals are the crops that leave the most residue on the soil surface, and this residue is considered very difficult to decompose within the time required between crops. It is estimated that approximately 55% to 75% of the total plant volume is residue.

[0026] Controlled burning is a common practice for managing crop residues in Chile, considered an economical method that allows for the rapid elimination of large volumes of waste. For example, it is estimated that between 80% and 90% of the wheat residue area (150,000 ha) in Chile's two most productive regions is managed through burning. Burning also contributes 29% of the particulate matter present in these regions. Inhalation of this particulate matter can cause respiratory failure and asthma, while prolonged exposure can lead to cardiopulmonary problems and cancer. This practice is currently regulated through periods of prohibition to minimize its negative effects on the environment and health, as well as the risk of fire spread.

[0027] Given this situation, significant resources of time and money have been invested in the search for new alternatives for the industrialized transformation of waste.

[0028] The state of the art presents some inventions that use mycelium, as can be seen, and shows different processes for producing it.

[0029] ES2497415A1 is a patent document that refers to a procedure for the growth of organic and biodegradable structures from agricultural waste and fungal mycelium, and their use as insulating components in construction, characterized by its design and manufacture of thermal and acoustic insulating structures, in accordance with a certain rigidity, 100% organic and biodegradable, using for this purpose agricultural waste (straw, wood chips, leaves, seed husks) and seeds of different species of fungi (Pleurotus ostreatus, Lentinula edodes, Ganoderma lucida m).

[0030] Patent document WO2022135757A1 discloses a flat insulating and / or construction element comprising a biologically produced composite material for thermal and / or acoustic insulation and / or for the installation of heating and / or supply systems. The composite material comprises a particulate substrate. The substrate surrounds and / or penetrates the mycelium of a fungus. The composite material exhibits self-supporting and / or elastic plastic properties. This document does not address the use of starting materials such as corn and wheat residues.Patent document CN103073224 discloses a method for preparing organic acoustic material involving (a) crushing material, where the material is wood chip generated during wood processing and / or agricultural production, (b) preparing culture material using crushed chip material and auxiliary materials, and disinfecting the culture material, (c) inoculating an edible mushroom strain into the culture material, (d) performing the cultivation, and (e) drying the product. The method is useful for preparing organic acoustic material for construction and packaging.

[0031] This document does not show that the material is obtained from straw and corn stubble, and it does not mention that it is biodegradable or compostable.

[0032] Patent document BR102022009786 discloses a process for the production of fungal biocomposites using lignocellulosic waste and byproducts, fungal biocomposites, and the use of said biocomposites for the production of civil engineering articles, soundproofing, and other applications. This document does not disclose that the material used is mycelium-based or that corn stover and straw are used.

[0033] The non-patent document “Mycelium Composites and Their Possible Applications in Architecture,” by Iñigo Conde, is a work based on the study of the technology for creating materials from fungal mycelium, focusing on its potential applications in construction. This document summarizes existing applications of mycelium and methods for obtaining it. While this document demonstrates uses of mycelium in construction, it differs from the solution proposed in this application in that it lacks evidence showing that the specific use of corn straw and stubble is the best option for forming acoustic panels.

[0034] Furthermore, it is reported that the properties of mycelium compounds are still being researched and experimented with. The most immediate field of application appears to be rigid thermal insulation, hence the vital importance of studying the material's strength and compression values.

[0035] Therefore, there is still a need for a type of bio-fabricated acoustic panel for construction that is 100% biodegradable, compostable, with excellent fire-resistant properties, and that is easy to obtain.

[0036] Description of the invention

[0037] The proposed solution to this problem is a bio-fabricated acoustic absorbent panel, classified as a low-density foam agglomerate, distinguished by its composition of plant fibers derived from corn stubble and wheat straw, and the use of mycelium as a biological binder. This makes it a completely biodegradable and compostable material. The panel described in this application possesses fire-retardant, thermal insulation, hydrophobic, and antistatic properties. It is designed for the acoustic conditioning of interior spaces such as bedrooms, offices, cinemas, theaters, museums, and others. The fungal mycelium allows for the development of materials with a renewable production cycle through the reuse of a wide variety of lignocellulosic waste generated by agricultural and forestry activities.Furthermore, its use in the manufacture of an acoustic absorption panel allows us to offer a competitive alternative with a lower environmental impact than the options currently available on the market.

[0038] The goal is to create an alternative that allows the development of new materials with a sustainable production system through the reuse of lignocellulosic waste, thus reducing dependence on the use of materials based on fossil fuels.

[0039] The panel of the present invention was subjected to laboratory tests with ISO 10534-2 certification demonstrating its good acoustic absorption performance in a relevant environment.

[0040] The panel production process does not require highly complex technology, as it uses low temperature equipment (<150 °C), in relation to the production of other materials.

[0041] For example, in the case of mineral wool, melting processes are used at temperatures exceeding 1450°C, compared to panels that require controlled ambient temperature (24°C - 30°C) and humidity. As a result, fewer negative externalities are generated, such as lower energy consumption and reduced pollutant emissions. The mycelium feeds on lignocellulose, expanding into a three-dimensional network within the substrate, acting as a binder. It develops optimally at room temperature during its cultivation process. This characteristic of the mycelium gives the resulting panel exceptional properties.

[0042] The panel has fireproof and thermal insulation properties and is designed for acoustic conditioning of interior spaces.

[0043] Its geometry is designed to improve its sound absorption performance.

[0044] Summary of the invention

[0045] A bio-fabricated, biodegradable, and compostable acoustic absorption panel is presented. Unlike the main alternatives currently on the market, it decomposes at the end of its useful life. It is made from mycelium and plant fibers derived from agricultural stubble of corn and wheat straw, recovered from harvesting processes in Chile.

[0046] Description of the figures

[0047] Figure 1a. Simple scheme of the panel biofabrication process based on mycelium and agricultural stubble.

[0048] Figure 1 b. Complete scheme of the panel biofabrication process based on mycelium and agricultural stubble.

[0049] Figure 2: a. MCM substrate wheat straw, b. MCM substrate corn cob with poplar sawdust, c. MCM substrate poplar sawdust, d. MCM substrate poplar shavings, e. MCM substrate corn cob. Figure 3. Comparison of the sound absorption coefficient of different materials used for acoustic panels. 3a: Sound absorption coefficient (MCM + plant fibers), 3b: Comparison of the sound absorption coefficient of MCM with other commercially available solutions based on natural fibers. 3c: Comparison of the sound absorption coefficient of MCM with conventional solutions.

[0050] Figure 4. Sample of the biomaterial made from mycelium and agricultural stubble.

[0051] Detailed description of the invention

[0052] The process of obtaining the biofabricated acoustic absorbent panel is described in Figure 1b:

[0053] A sample of mycelium (1) is collected and sterilized (2). It is then cultured in a Petri dish (3) to allow the mycelium to grow (4). Spawn (5), the inoculum in which the mycelium is incubated in the first stage, is then inoculated. The mixture is then poured (6) into a predetermined mold (7). Incubation of the material requires time, humidity (70%–100%), and temperature (24°C–30°C) (8). The mold is then baked (9), and the finished material (10) is obtained. This material is biodegradable and can therefore be composted (11), decomposed, and reintegrated into natural decomposition cycles (12).

[0054] The mixture used to manufacture the biofabricated acoustic absorbent panel comprises:

[0055] The substrate consists of plant fibers, between 40% and 50% wheat straw and 50% to 60% corn stover (cob, stalks, leaves), based on the dry weight of the substrate. The substrates are hydrated in water that completely covers them for 1 hour, after which any excess water is removed. Based on the weight of the hydrated substrates, 10% spawn (grains of brown rice or other cereal, inoculated with mycelium), 1% coffee grounds, and 0.5% lime are added.

[0056] Acoustic absorption coefficient ISO 10534-2

[0057] One of the most common techniques for absorbing acoustic energy is to use porous materials such as foams. The sound waves travel through interconnected pores, reflecting a very small portion of them and transforming the rest of the absorbed energy into heat.

[0058] Mycelium composite materials (MCMs) have low densities, which vary depending on the type of substrate used. This is because plant fibers have a microstructure with walls that trap air, contributing to a low-density material, making them ideal for acoustic applications.

[0059] The described MCM ranges in densities between 50 and 120 kg / m³ 3 This makes it equivalent to other synthetic polymer foams, such as polyurethane (30-100kg / m³). 3 ), expanded polystyrene (12-50kg / m³ 3 ) and mineral wool (60-150 kg / m 3 )

[0060] The sound absorption coefficient is a key performance indicator for acoustic materials, showing how much sound is absorbed at different frequencies. On the absorption spectrum, 0 indicates perfect reflection and 1 indicates perfect absorption. Therefore, a material with an absorption coefficient of 0.9 absorbs 90% of the sound, while reflecting 10%.

[0061] The acoustic absorption test was performed according to a method called impedance tube in accordance with ISO 10534-2 in the ACUSONIC laboratories by an acoustic consultant with current registration in the MINVU.

[0062] To evaluate performance, MCM test specimens were prepared using four different substrates and the Pleurotus ostreatus mushroom to allow for comparison based on different densities and fiber types. The test specimens were cylindrical with a diameter of 47 mm (standardized value for this test) and a thickness of 50 mm. This thickness was chosen based on a common thickness used in acoustic absorption panels to ensure a comparable comparison.

[0063] As a result of the test, as can be seen in the graphs presented below, in figure 3 a, they obtained a sound absorption coefficient (NRC) between 0.5 and 0.7 which represents a good result for an acoustic material, even superior to the performance of some materials that are currently marketed for this function.

[0064] The results presented in the graphs of Figures 3 and 3c demonstrate performance equivalent to that of other materials for mid and high frequencies (above 1000 Hz), and a particularly outstanding result for low frequencies (125-1000 Hz), where other products exhibit a considerable drop in performance. Among the samples tested, the performance of the wheat straw MCM and the corn cob MCM stood out, demonstrating a relationship between acoustic absorption performance (NRC 0.7) and the material's structural strength.

[0065] It should be noted that for this test, the corncob was evaluated in combination with sawdust, not on its own, due to technical difficulties arising from the material's shrinkage and friability. However, the results obtained suggest that the NRC value obtained by the sample is due to the corncob, since the sawdust sample alone had the worst absorption coefficient.

[0066] Technical aspects of production

[0067] The biggest problem with mycelium composite materials is the demolding process once the self-assembly process has been completed.

[0068] The solution researchers found to overcome these problems lies in the substrate. Surprisingly, they discovered that the best way to prevent demolding is to use corn stover as part of the substrate. This promotes non-adherence of the material, contributing to more efficient and effective demolding.

[0069] The microstructure and material composition of corn stover exhibit a tendency towards water permeability. The cob, for example, can absorb up to 300% of its weight in water, expanding by 10-20%, increasing in size with moisture and decreasing in size upon dehydration. This phenomenon reduces the vacuum or suction effect created when manufacturing composite materials with mycelium in molds, facilitating their demolding.

[0070] Description of preferred options

[0071] In a first embodiment, a procedure is described for preparing an acoustic biomaterial comprising: a. collecting a mycelium sample, b. sterilizing culture medium for incubating the collected mycelium sample, c. cultivating in a Petri dish with nutrient culture medium to facilitate mycelium proliferation, d. inoculating sterilized cereal grains or other types of cereals such as wheat, corn, brown rice, rye, millet, oats with the mycelium sample, e. grinding the substrate of corn stover (stalk, leaves, cob) and wheat straw to obtain a particle size between 5 mm and 50 mm as required, f. mixing the inoculum with the sterilized substrate and incubating in a container for 3 to 7 days at a controlled temperature between 24°C - 30°C and ambient humidity between 70% - 100%, g.Fill a predetermined mold with the previously incubated mixture for a period of 7 to 21 days until the mycelium is completely colonized, evaluating the whiteness of the substrate by visual inspection. h. Remove the material from the mold and incubate it in an airtight container for at least 3 to 7 days or until a surface coating of mycelium is obtained on the material. i. Dehydration drying treatment: the material is gradually dried at a temperature between 50°C and 70°C in a well-ventilated environment for a period of 72 hours. Subsequently, the cured molded material is obtained.

[0072] In another embodiment of the invention, there is a material manufactured using the described procedure, which comprises

[0073] • Substrate of vegetable fibers that corresponds to 30% to 60% w / w wheat straw and 40% to 70% w / w corn stubble (stem, leaves, cob), based on the weight of the substrate.

[0074] • 6 to 9% spawn, which corresponds to grains of brown rice, or other cereal, inoculated with the mycelium

[0075] • 0.5% and 3.5% Coffee Grounds and

[0076] • 0.5% of Cal.

[0077] In another preferred modality, the above material is described, such that the cereal with which the spawn is made is a cereal that can be chosen from: wheat, corn, barley, canary seed, brown rice, millet.

[0078] In another preferred modality, the above material is described such that the mycelium is obtained from fungal species.

[0079] In another preferred embodiment, the aforementioned material is described, such that the fungal species is selected from among Pleurotus ostreatus, Ganoderma lucidum, Trametes versicolor, Lentinula edodes, saprotrophic fungi belonging to the Phylum Basidiomycota, or other white-decomposing species. In another preferred embodiment, the use of the material is described as being suitable for manufacturing a bio-fabricated acoustic absorber.

[0080] In yet another preferred modality, the previous use is described, such that the acoustic absorber is panel-shaped.

[0081] In another preferred modality, the above use is described because it serves for the construction of walls, acoustic rooms, partitions, and roofs.

[0082] In another preferred modality, the above use is described such that the panel is 100% biodegradable and compostable.

[0083] Regarding studies conducted on substrates

[0084] This investigation was carried out with five substrates (see Figure 2)

[0085] 1. It was identified that the development of the mycelium in straw and cob substrates is faster compared to other substrates.

[0086] 2. Of all the substrates, corncob stood out in the demolding process. The critical areas (corners and edges) that presented the greatest difficulty in demolding came out in a single piece, without breaking, without any areas adhering to the mold, in less time, and without the need for any additional techniques such as drilling holes in the mold to allow air in or breaking it to release the panel, as was the case with the other substrates. A comparative test was also conducted, mixing corncob with poplar sawdust, the substrate that presented the greatest difficulty in demolding. A considerable improvement was identified, with no areas adhering to the mold and the panel coming out in one piece without additional techniques. This was not possible with the sawdust substrate, as it presented many areas of adhesion upon demolding and carried a high risk of fracture.

[0087] Regarding this, it was concluded that because the test samples were made with the same species of fungus under the same incubation conditions and in the same type of mold, the differences in the difficulty and quality of demolding are mainly due to the type of fiber used:

[0088] It was demonstrated that the corn cob samples shrank to 15% of their original size. This property allows the panel to detach naturally from the plastic without forcing the mold. Additionally, it has been determined that this property can be regulated by the percentage of water initially added.

[0089] 3. Finally, while the corncob substrate offered beneficial properties for panel production, it exhibited deficiencies in its mechanical strength. Once demolded, the panel was weak, fracturing and crumbling during handling. In contrast, straw was the substrate with outstanding mechanical strength, as the panel did not fracture and did not require delicate handling. However, this substrate also presented difficulties during demolding.Therefore, when evaluating the properties of both potential substrates, it was concluded that the combination of both (Wheat Straw + Corn Stalks) would be ideal to achieve a composite material with a highly resistant part, given by the long fiber of the wheat straw and following this same logic adding corn stalks, such as the stem, to enclose the granulation of the corn cob, and that, on the other hand, it will present excellent demolding thanks to the properties of the latter.

[0090] The results confirmed the hypothesis, showing the surprising effect that was expected.

[0091] 4. The substrates studied, being plant fibers, have a microstructure with walls that store air and can contribute to obtaining a low-density material, which makes these materials ideal for acoustic applications.

[0092] Advantages associated with this technology: a) Thanks to its completely natural and biodegradable composition, the panel described in this application has fewer negative environmental externalities. It is estimated that MCMs can achieve a negative carbon footprint (-39.5 kg CO2eq m²). 3 ) and, therefore, considerably lower compared to the production of other materials currently marketed such as EPS, PUR or mineral wools which range between (42-172 kg CO2eq m 3This is thanks to the CO2 absorbed by cereal crops during their growth, which is then used as raw material for the product. It also minimizes waste management and pollution problems at the end of its useful life, as this product is completely biodegradable. b) The panel described in this application does not contain any additives harmful to health in its composition, unlike products such as PU foam or mineral wool. This allows for a safer product not only for end users but also for workers, as its production process is less harmful. c) The product offers a competitive advantage in terms of its sound absorption capacity at low frequencies (<2000 Hz). The panel of the present invention has been shown to have a superior absorption coefficient compared to other solutions available on the market (see Figures 3 and 3c).This feature addresses one of the main shortcomings and technical challenges of current commercial panels, which often require increased product thickness or the combination of different types of materials, significantly increasing production costs. This was one of the aspects most highly valued in consultations with a panel of experts from the Chilean acoustic solutions industry, representing companies such as Iberacústica and Silentium. It is also worth mentioning that the panel of the present invention, compared to other acoustic panels made from plant fibers available on the market, has superior sound absorption performance, as demonstrated. d) It contributes to addressing the problem of crop residue management in Chile, reducing controlled burns that produce pollution and poor air quality.e) It does not require highly complex technology, as it uses low-temperature equipment, in relation to the production of other materials, such as mineral wool, which requires a melting process at temperatures above 1450°C.

[0093] Thus, based on the results obtained in the present invention, it can finally be concluded that the bio-fabricated, biodegradable and compostable acoustic absorbent panel made from the mycelium of fungal species has a high acoustic absorption performance, since the acoustic absorption coefficient tested and shown in Figure 3 represented a good result and performance for an acoustic material, even superior to the low-frequency performance of some materials that are currently marketed for this function.

[0094] While this invention has been described in the embodiments indicated above, it might seem obvious that other alternatives, modifications, or variations would yield the same results. However, we have established that the subject matter described in this application is fundamental to the success of the invention described herein. Consequently, the embodiments of the invention are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention as defined in the following claims.

[0095] All patents, patent applications, scientific articles and other public documents that, to the applicant's knowledge, constitute the state of the art, have been duly cited in this application.

Claims

CLAIMS 1. A bioacoustic absorbent material, CHARACTERIZED in that it comprises: - Substrate of vegetable fibers that corresponds to 30% to 60% w / w wheat straw and 40% to 70% w / w corn stubble (stems, leaves, cob), based on the weight of the substrate. - 6 to 9% spawn, which corresponds to a cereal inoculated with mycelium, - 0.5% and 3.5% Coffee Grounds and - 0.5% of Cal.

2. The material described in claim 1, CHARACTERIZED in that the cereal used to make the spawn is a cereal that can be chosen from: wheat, corn, barley, canary seed, brown rice, millet.

3. The material described in claim 1, CHARACTERIZED in that the mycelium is obtained from fungal species.

4. The material described in claim 3, CHARACTERIZED in that the fungal species is selected from Pleurotus ostreatus, Ganoderma lucidum, Trametes versicolor, Lentinula edodes, Saprotrophic fungi belonging to the Phylum basidiomycota, and other white decomposition type species.

5. The use of the material described in claim 1, CHARACTERIZED in that it serves to produce a bio-fabricated acoustic absorber.

6. The use described in claim 5, CHARACTERIZED in that the acoustic absorber is panel-shaped.

7. The use described in claim 6, CHARACTERIZED in that the panel serves for the construction of walls, acoustic rooms, partitions, and roofs.

8. The use described in claim 7, CHARACTERIZED in that the panel is 100% biodegradable and compostable.

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