Fermentation-based binder for use in paving material production, a package, a composite material, a method for making a fermentation-based binder, and a method for constructing a paved area

Abstract

A fermentation-based binder for use in paving material production is disclosed. It comprises an organic substrate, a preselected fungus configured to consume the substrate. The organic substrate comprises a nutrient material, said nutrient material being capable of being digested by said fungus such that mycelium is grown. The binder further comprises a fluid allowing the mycelium to grow. A package for use in paving material production is also disclosed. A composite material material for use as a paving material production is also disclosed. A method of providing a fermentation-based binder, and a method for constructing a paved area are also disclosed.

Description

[0001] Title of Invention

[0002] Fermentation-based binder for use in paving material production, a package, a composite material, a method for making a fermentation-based binder, and a method for constructing a paved area.

[0003] Technical Field

[0004] The present invention relates to a fermentation-based binder for use in paving material production. The invention further relates to a packaging for use in a paving material. The invention also relates to a composite material for use as a paving material production. The invention also relates to a method for making a fermentation-based binder. The invention further relates to a method for constructing a paved area.

[0005] Background Art

[0006] The building industry and the production of construction materials account for 33% of global greenhouse gas emissions and consume 40% of the global energy production. Road construction is an energy intensive industry classified under the same energy intensive category as concrete. Asphalt is the main paving material used for road construction. Asphalt is typically produced by approximately 95% rock materials and 5% binder material, which traditionally has been bitumen, but nowadays includes modified bitumen or biological binders such as lignin. Asphalt production is today dependent on the expensive and volatile bitumen supply. The production of bitumen is, however, highly inefficient as it is made from oil residues, of which only 10% is fit for use. In addition, bitumen requires high temperatures during production, making it both economically and environmentally costly. Furthermore, although asphalt is recyclable in theory, currently new asphalt only contains 40% of reclaimed asphalt pavement (RAP) on average in e.g. Denmark, and the recycling process requires substantial energy consumption when the asphalt is reheated in the process. New solutions are therefore needed to minimize the environmental risk associated with paving material production and make it more sustainable and efficient. Hybrid binders comprising bitumen and other materials may have previously been developed, however these are often associated with the same risks and issues. Furthermore, the paving material production is unique in the sense that certain requirements to the strength, texture, durability of the paving material are required, which are difficult to obtain.

[0007] Summary of Invention

[0008] With this background, it is therefore an objective of the invention to provide a binder that solves or at least alleviates the above-mentioned problems. Specifically, it is an objective of the invention to provide a binder which is sustainable, elastic, and strong to use for paving material production.

[0009] According to a first aspect of the present disclosure, this object is achieved by a fermentation-based binder for use in paving material production, comprising an organic substrate, a preselected fungus configured to consume the substrate, wherein the organic substrate comprises a nutrient material, said nutrient material being capable of being digested by said fungi such that mycelium is grown, and a fluid allowing the mycelium to grow.

[0010] By providing such a biological fermentation-based binder, it may be possible to decompose the binder by biological processes.

[0011] The fermentation-based binder is based on growth of hyphae, collectively referred to as mycelium or mycelia, and its derived metabolic activity resulting in metabolites such as excreted minerals, proteins, acids, fibers, respiration liquid, lipids, and / or gasses. The resulting mycelium growth and metabolites can collectively be called biomass and constitutes the biological binder material.

[0012] The fermentation-based binder may either partially or fully replace oil-based binders, such as the oil derivate bitumen, in paving material production or in paving material repair.

[0013] It should be understood that paving materials refers materials used to pave an area, such as a mixture of aggregates or hard particles and a binding agent, such as bitumen and / or the fermentation-based binder. The paving material may also comprise one or more additives and / or fillers, such as vax, sand, concrete lime, hydrated lime, cellulose fibers, fly ash, dust, stone flour, and / or sand. The additives may have a particle size below 0.063 mm.

[0014] The natural binding property of fungi is utilized in the binder. When the mycelium grows, it may achieve a binding property through vegetative growth and digestion of an organic substrate. The binding property may also be obtained through the excretion of metabolites from and together with the vegetative growth. The binding property may be obtained together with hybridizing the mycelium with an organic or inorganic binder, such as lignin or zeolite. The binding property may be obtained through genetical engineering of a fungal strain, which function may or may not be guarded by an inducer, such as a gene deletion and / or a molecule that may be a transcription factor, transcriptional activator, enzyme, glycosylated proteins, sugar, glucose, extract, growth regulator, growth stimulator or hormones. The molecule may regulate fungal metabolisms by interacting with cell membrane receptors and / or mycelium cell cytoplasm. The binder may be able to bind together particles, and thereby holding a different material together. For instance, the binder may bind loose aggregates together to create a composite material. The binder may have elastic properties. The mycelium may provide the elastic properties of the binder.

[0015] The biological fermentation-based binder may constitute no biohazard to its environment. If the binder spreads to unintended areas, it may be beneficial for the environment by promoting biodiversity and potentially have a bioremediation effect that improves the soil quality and protects against corrosion.

[0016] The binder may be adapted to grow in bitumen remains, making it suitable for being used with RAP.

[0017] The binder may produce minerals, a process called biomineralization, which may harden the paving material, making it more endurant over time. Biomineralization is a natural process which creates new rock material by the metabolic activity of the fungus, e.g. by excretion of calcium carbonate. The biomineralization may produce a mineral matrix providing binding effects by interlocking the rock particles in a structural framework consisting of mineral coating and potentially mycelium remains. The binder is for being mixed with a different material, preferably aggregates. The term "aggregates" refers to hard particles suitable for being used in paving materials, such as crushed limestone, gravel, rocks, such as granite rocks, RAP, ash, glass, slag and / or concrete.

[0018] An advantage is that the binder may be mixed with the different materials in a humid, wet, or dry environment. This may enable that the binder may be applied in different environments. In paving material production, the producers typically need to evaporate residual water from the aggregates before mixing with bitumen, which is a very energy-consuming process. Therefore, it may be possible to save energy by using the fermentation-based binder rather than bitumen and the like materials.

[0019] Another advantage is that the binder may be mixed with the different material, preferably aggregates, in situ or on-site, and with no subsequent extraction or separation to obtain the binding effect of the binder. Downstream processing of the binder by additional heat treatment, compression, isolation, contaminant removal, purification, polishing, grinding, shredding, chopping, and / or other treatments might improve the binder properties in the paving material. Downstream processing refers to the recovery and the purification of biomass, including for example mycelium and / or biosynthetic products.

[0020] Another advantage is that the different material may be reused. In an embodiment, in which the binder is mixed with aggregates, the aggregates can be reused and mixed with a new fermentation-based binder to create paving materials, without the need to heat the material to high temperatures. The original fermentation-based binder may be composted or in other ways recycled by deposition in a suitable environment.

[0021] By using a fermentation-based binder, paving material mixing and production may be possible at lower temperatures, which makes the use of it more flexible and sustainable.

[0022] In an embodiment, the intended use of the fermentation-based binder is in the range of -20°C to 75°C, preferably -20°C to 60°C, preferably -20 to 45°C, preferably -20 to 30°C. The fungus may die if the temperature exceeds the temperature intervals or the opposite.

[0023] The mycelium may grow up to 80°C, preferably 50°C and may be stored down to -80°C.

[0024] An organic substrate is used to produce the fermentation-based binder. The organic substrate and / or the nutrient material may be a waste product from a related and / or unrelated process, subjected to fermentation prior, during or after the mixing with the aggregates. The organic substrate and / or the nutrient material may comprise one or more selected from the group consisting of starch, straw, hay, hemp, wool, cotton, rice hulls, oat waste, oil press cakes, cellulose, paper waste, lignin, biorefinery waste such as liquid residues and / or biorefinery fibers, preferably comprising sugar and / or food production side stream products, brewers spent grain, brewers spent yeast, sugar, compost, lupin, manure, paper pulp, liquid and sawdust, preferably recycled sawdust. The organic substrate may be chosen to provide the optimal nutrition of fungi. These materials may induce and / or promote growth of the mycelium and / or the binder.

[0025] An advantage of the organic substrate comprising the nutrient material may be that no further materials are needed for the mycelium to grow. The mycelium may consume and / or bind the substrate completely, leaving no waste material.

[0026] In an embodiment, the organic substrate and / or nutrient material may comprise agricultural waste product and / or food production side stream products. Food production side streams relates to renewable feedstocks that could be used in the circular economy era for the production of bio-based materials. These products may be easy to access and available at minimum cost.

[0027] In an embodiment, the organic substrate comprises at least one cavity, such that the mycelium is grown into or through the at least one cavity. By providing at least one cavity, the mycelium may colonize the substrate in a faster manner. The cavity may be understood as a hole or an enclosed space within the substrate. The cavity may contain air and / or liquid. The substrate may have more cavities for increasing the speed of colonization by the mycelium. The cavity provides space in which the mycelium can grow. The cavity may also provide heat exchange and gas exchange. The conversion of the substrate into fungal biomass may fill out the cavity and increase material density.

[0028] In an embodiment, the organic substrate has a pH value in the range of 3-9, preferably 4-7, more preferably 5-6.5. This pH value range may provide optimal conditions for the mycelium growth, thereby ensuring an efficient production of the binder. It is to be understood that the pH value of the organic substrate may change during the lifespan of the fungus. The pH value may be adjusted manually by adding pH regulators, such as hydrochloric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, and / or pH buffers, such as calcium sulphate, to the substrate and / or by acidic and / or alkaline compounds excreted by the fungus during fermentation, when the fungus is mixed with the substrate.

[0029] In an embodiment, the fungus is a filamentous fungus. The fungus may be a basidiomycota, including a white-rot and / or a brown-rot fungus. The fungi may be chosen from the group of Ganoderma spp., Ganoderma lucidum, Ganoderma curtisii, Ganoderma sessile, Ganoderma resinaceum, Ganoderma curtisii, Trichoderma reseei, Trichoderma asperellum, Fames fomentarius, Plerotus spp., Pleurotus ostreatus, Pyc- noporus sanguineus, Schizophyllum commune, Polyporus arcularius, Trametes spp., Trametes versicolor, Trametes pubescens, Trametes suaveolens, Trametes hirsute, Trametes multicolor, Trametes ochracea, Coprinus (Coprinellus) lagopus, Phanero- chaete chrysosporium, Gloeoplyllum spp., Gloeophyllum abietinum, Gloeophyllum se- piarium, Gloeophyllum trabeum, Acidomelania panicicola, Abortiporus biennis, Agro- cybe aegerita, Allomyces arbusculus, Aspergillus nidulans, Bjerkandera adusta, Chrysosporium spp., Coniophora puteana, Coprinellus micaceus, Coriolopsis gallica, Clonostachys rosea, Daedaleopsis tricolor, Dichomitus squalens, Fomitopsis spp., Fom- itopsis betulina (Piptoporous betulinus), Fomitopsis iberica, Fomitopsis palustris, Fomitopsis pinicola, Flammulina velutipes, Hypsizygus marmoreus, Irpex lacteus, Irpex latemarginatus, Kuehneromyces mutabilis, Laetiporus sulphureus, Lentinus spp., Lenzites betulina, Lenzites betulinus, Lycoperdon pyriforme, Megasporoporia minor, Mortierella gamsii, Mortierella alpina, Mortierella verticillate, Mortierella vinacea, Mucor spp., Mucor mucedo, Oxyporus latermarginatus, Paecilomyces spp., Paecilomyces inflatus, Paecilomyces lilacinus, Phanerochaete chrysosporium, Phel- linus ellipsoideus, Piptoporus betulinus, Polyporus spp., Polyporus arcularius, Polypo- rus brumalis, Polyporus pulmonarius, Plectosphaerella cucumerina, and Stereum hir- sutum.

[0030] It is to be understood that the binder may comprise more than one fungus of the same and / or a different type or species.

[0031] In an embodiment, the fungus may not be able to grow fruiting bodies and / or sporulate, either by mutation, wild-type or by environmentally induced conditions such as temperature control or the addition of a fruiting-body repressor such as a chemical compound.

[0032] In an embodiment, the fluid comprises air and / or water, which allow the mycelium to grow. The water may be embedded in the binder and / or provided freely, forming small pools on the surface. Fluids are important for the environment in which the mycelium may grow.

[0033] In an embodiment, the binder is in a solid state, preferably comprising discrete particles. The discrete particles may allow the mycelium of the binder to grow through and around the particles, thereby binding the discrete particles together.

[0034] In an embodiment, the fermentation-based binder comprises a substrate mycelium and an aerial mycelium. The substrate mycelium is embedded in the substrate residue. The aerial mycelium may be coating the binder and / or inside the substrate residue. The aerial mycelium may be more dense and / or of higher strength and / or flexibility than the substrate mycelium.

[0035] In an embodiment, a maximum particle size of the binder is less than 10 cm, preferably less than 5 cm, more preferably below 2 cm. This may enable the binder to grow into cracks and / or cavities of the aggregates and thereby increase a contact area between the binder and the aggregates. This may improve material properties, such as the strength and / or stiffness, of the composite material. The particle size may be achieved through blending of the binder prior to being mixed with the aggregates.

[0036] In an embodiment, in a final state of the production of the fermentationbased binder, the binder comprises 50 wt.% organic substrate, 50 wt.% mycelium. Alternatively, the organic substrate may account for 10 wt.%, 20 wt.%, 30 wt.% or 40 wt.% of the binder. The organic substrate may alternatively take more than half of the composition of the binder, such as 55 wt.%, 60 wt.%, 65 wt.%, 70 wt.%, 75 wt.% or 80 wt.% of the binder. The mycelium may account for 95 wt.%, 90 wt.%, 80 wt.%, 70 wt.% or 60 wt.% of the binder, respectively. Alternatively, the mycelium may account for 45 wt.%, 40 wt.%, 35 wt.%, 30 wt.%, 25 wt.%, 20 wt.%, 15 wt.%, 10 wt.%, 5 wt.%, or 1 wt.% of the binder.

[0037] The ratio of mycelium and substrate of the binder may affect the binder's resistance to biological factors, wherein a high mycelium content may help outcom- pete otherfungi, mould, bacteria, micro- and / or macro organisms, such as insects and slugs. A high mycelium content may be advantageous in situation where the binder and / or the composite material is produced in non-sterile conditions.

[0038] In an embodiment, the mycelium growth is slowed down, such that retardation from fully degradation of the substrate is achieved. This may prevent excess cavity formation. Over time, full colonization of the substrate by the mycelium may be achieved.

[0039] The binder may preferably be rested or left undisturbed for 1 to 28 days. Within this period the mycelium may be disturbed by breaking it up mechanically and / or by mixing a minimum of one time, and thereafter be left to rest again.

[0040] According to another aspect of the invention, a package for use in paving material production comprising the fermentation-based binder of claim 1 is provided, the package further comprises a container with an internal space, the container comprising a sanitized internal space accommodating the binder, wherein the substrate comprises at least one cavity, in which the mycelium can grow, is provided.

[0041] The container may act as a structural member, providing a growth barrier to the binder, such that unintentional mycelium growth may be avoided. By acting as a structural member, the container may provide for a desired shape of the binder and / or the composite material.

[0042] The container may serve as a humidity barrier and maintain a humid environment by preventing evaporation, such that good growth conditions of the binder is maintained.

[0043] The humid environment and / or the shape of the binder may result in improved material properties, such as rigidity, of the binder and / or the composite material.

[0044] During growth of the binder, it is important to provide a humid environment to facilitate growth of the fungus. When the composite material has been applied to pave an area, less humidity is beneficial to obtain strength and rigidity of the paving material, as most binder materials will be stronger and / or stiffer when dry. However, a curing period after application of the paving material may be beneficial, and during such period a humid environment may be advantageous. To ensure a humid environment, water may be added to the paving material.

[0045] In case the composite material comprises excess water, the water may be extracted from the material, for example by heating and / or centrifuging.

[0046] The water content of the substrate and / or aggregates should be taken into account, as for example a dry substrate and / or aggregate may absorb water, thereby reducing the need for water extraction. A substrate and / or aggregate with a higher water content may induce a need for water extraction.

[0047] The container may be made of any suitable material for the intended use of the package, such as plastic, wood, metal, steel, paper-based materials, plant fibers, textile fibers, gypsum, clay, rubber, spray coating, and / or concrete. The container may be perforated and / or comprise a filter to allow air exchange, such that the container is not completely sealed.

[0048] In an embodiment, the container is made from or comprises a flexible material, allowing the container to stretch or expand when the bindergrows substantially in size and thus does not absolutely restrict it.

[0049] In an embodiment, the container has a length and a width, wherein the length is greater than the width of the container. The dimensions of the container may be important for heat and / or gas exchange, and by having a greater length than width of the container, the heat and has exchange may be efficient. The heat and gas exchange may take place through at least one of the sides of the container, while the mycelium colonizes the organic substrate. The container may also have other suitable dimensions.

[0050] According to another aspect of the invention, a composite material comprising the fermentation-based binder of claim 1 and aggregates, is provided.

[0051] In an embodiment, the binder is considered a living material during manufacturing and / or use, that is the fungus may still consume the organic substrate. Living means that the mycelium may interact with the environment and that the binder may comprise the properties of a living fungus. For instance, the mycelium may be selfrepairing or self-supporting by biological proliferation, by mycelium growth in cavities between discrete particles of aggregates, fuelled by the fungal digestion of the organic substrates. The living function may also be obtained by fungal spores residing in the material while the mycelium has been inactivated. The fungal spores may germinate and grow mycelium when activated by the presence of substrate, air, water, and a suitable cavity for growth. The fungal spores may function the same way as the mycelium before it was inactivated. The properties, such as the strength or stiffness, of the binder may improve with time, as the fungus may continue to consume the substrate and promote mycelium growth. It may continuously grow into cavities and cures in the aggregates. The living binder may be able to adjust to outdoor conditions, making the binder a more resistant material being able to combat potentially damaging microorganisms. For instance, mycelium growth may be enhanced during times of high temperatures, whereas the growth may be slowed down in periods of lower temperatures. Rain may provide a humid environment which may enhance growth of the mycelium.

[0052] The properties of the binder may improve over time. It has been observed that the material has a higher strength after two months compared to after two weeks.

[0053] In an embodiment, the fungus of the composite material is inactivated, preferably by heating it to sufficient temperatures or by drying it to remove any residual water, preferably after pavement construction, possibly after a curing period, which may be in the range of 1 hour to one month. This prevents further unintended growth of the mycelium. An inactive composite material means that the fungus of the composite material and / or its spores does not interact with the environment. Heat inactivation may happen at temperatures above 40°C. The fungus of the composite material may alternatively be inactivated by exposure to temperatures below 5°C. Different fungi have different inactivation temperatures.

[0054] Paving materials are typically applied onto a base. The base may comprise several layers of different materials. In an embodiment, a first layer is provided under the composite material, such that the first layer is covered by the composite material. By providing a first layer, the composite material may be protected from unwanted substances and / or microorganisms.. The first layer may comprise gravel, aggregates, plant fibers, plastic, wood, metal, steel, paper-based materials, textile fibers, gypsum, and / or concrete.

[0055] The composite material may be shaped and / or reshaped to a desired geometry. This may for instance be done by disrupting the mycelium growth and allowing for succeeding growth and rehybridization by the hyphae. This feature may allow for a surface evening of the paving material containing the binder once it is transported from the paving material factory and onto the site. The binder may be evened, for example by drumming and / or rolling, and subsequent resting time to harden and increase cohesiveness of the material by mycelium growth. The curing time of the paving material may take between lOand 60 days, preferably 1 to 30 days, more preferably 1 to 10 days, more preferably 1 to 5 days, more preferably less than 2 days.

[0056] In an embodiment, the curing time of the paving material is less than 1 hour.

[0057] In an embodiment, there is no curing period.

[0058] The shape of the composite material may be achieved by providing a confined space, for example the package.

[0059] In an embodiment, a coating layer is provided on the composite material. The coating layer may comprise an additive, such as glycerol, glycerine, vegetable oil such as rapeseed oil, glue, wax, natural gums, such as Xanthan and guar gums, molasses, methyl cellulose, proteins, modified starch, sodium carboxymethyl cellulose, modified humic acid, polyacrylamide, lignin sulfonate, paper, lignin, bitumen, clay, lime, cement, gypsum, liquid glass, epoxy, polyester, pitch resin, phenolic resins, non- organic aggregates, bio-resin, and / or sand, preferably carbonate sand. The coating layer may comprise more than one additive, such as bitumen, bio-resin, and / or wax. The coating layer may protect the composite material. The coating layer may serve as a barrier, preferably an impermeable barrier to water, salt and / or sun and / or protection against wear and tear by traffic. When applied with a coating, the mycelium may comprise an inert feature and may be substantially resistant to contamination and / or decomposition.

[0060] The coating layer may comprise paving material mixtures designed for surface layer functionality, such as slurry shield, vegecol, bitumen stabilized materials, and / or other paving material mixtures produced with bitumen, bitumen emulsions and / or biobased binders. A traditional asphalt surface and other traditional paving materials follow pavement regulations in terms of noise, friction, light reflection, aqua planning prevention, etc., and by providing the coating layer to the composite material, these regulations may be easier to follow.

[0061] In a preferred embodiment, the composite material comprises a plurality of cavities. The cavities or holes may enable a space for growth of the fermentationbased binder. The growth of the binder may be fuelled by continuous digestion of the organic substrate by the mycelium. The plurality of cavities provides for a space in which the mycelium can grow. This property may demonstrate the ability of the binder to heal cracks or breaks in the composite material.

[0062] The composite material may allow for a self-repairing or self-supporting feature by biological proliferation, by mycelium growth in the cavities between discrete particles of aggregates, fuelled by the fungal digestion of the organic substrates.

[0063] The stiffness modulus of the composite material is preferably in the range of 100 MPa to 5000 MPa, preferably 200 MPa to 3500 MPa, preferably 300 MPa to 2000 MPa. The stability of the composite material as measured by Marshall stability tests may be in the range of 1000 kN to 10000 kN, preferably 2000 kN to 8000 kN, preferably 4000 to 6000 kN, preferably 5000 kN.

[0064] In an embodiment, the composite material comprises 1 wt.% binder, 99 wt.% aggregates. Alternatively, the binder may account for 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.%, 35 wt.%, 40 wt.%, 45 wt.% or 50 wt.% of the composite material. The different material, such as aggregates, may account for 95 wt.%, 90 wt.%, 85 wt.%, 80 wt.%, 75 wt.%, 70 wt.%, 65 wt.%, 60 wt.%, 55 wt.%, or 50 wt.% of the composite material, respectively.

[0065] In an embodiment, the binder of the composite material accounts for less than 40 wt.% of the composite material, preferably less than 20 wt.% of the composite material, more preferably less than 15 wt.% or no more than 10 wt.% of the composite material.

[0066] In an embodiment, the composite material is densified by compression. This may improve the strength and / or stiffness of the composite material.

[0067] In an embodiment, the composite material comprises an additive to improve material properties. The additive may increase the density of the composite material, which may improve the material strength. The additive may improve stability of the binder and / or the interlocking of the aggregates into a matrix. The matrix may distribute forces, such as externally applied pressure due to traffic, across a rock-to-rock interphase. The strain distributed across the matrix may thereby improve the material strength of the composite material. The additive may be water, glycerol, glycerine, vegetable oil such as rapeseed oil, glue, wax, natural gums such as Xanthan and guar gums, molasses, methyl cellulose, proteins, modified starch, sodium carboxymethyl cellulose, modified humic acid, polyacrylamide, lignin sulfonate, paper, lignin, bitumen, clay, lime, cement, gypsum, liquid glass, epoxy, polyester, pitch resin, phenolic resins, non-organic aggregates and / or sand, preferably carbonate sand. The composite material may comprise more than one type of additive.

[0068] In an embodiment, the additive comprises an active component dissolved or dispersed in water. Water may facilitate distribution of the active component and / or increase the humidity of the environment and / or substrate. This may help the binder attach to the aggregates, such that a matrix is created around the aggregates.

[0069] In an embodiment, the package may be provided with an air supply. The air supply may be in the form of an opening or perforated pipes to increase the air flow. This may be in particularly helpful in dense materials. In an embodiment, the container is sanitized. The container may be sanitized using soapy water, alcohol, and / or gas such as ozone and rinsed. By providing a sanitized container, the mycelium growth can be controlled to a greater extend compared to a non-sanitized internal space by preventing contamination.

[0070] It is another object of the invention to provide a method for producing the binder of claim 1, comprising the steps of providing a container with an internal space containing a fluid, preferably air and / or water, the internal space in the container being sanitized; providing an organic substrate comprising a nutrient material in the container; providing a preselected fungus in the container, said fungus being capable of digesting the nutrient material, mixing the fungus with the substrate, such that said fungus digests the nutrient material and mycelium is grown.

[0071] In an embodiment, the fungus and the substrate are mixed to obtain a homogenous binder, such that the fungus is substantially dispersed in the substrate. This may allow the mycelium to grow in a homogenous way. The mixture of fungus and substrate may inherently be heterogenous with the fungus and substrate being intermixed at different stages of biomass conversion.

[0072] In an embodiment, the fungus is divided into smaller particles, for example by shredding. This may allow for a plurality of growth starting points of the fungus when mixed with the substrate, thereby increasing an area of growth and contact nodes. Likewise, the binder may be divided during growth to further distribute the fungus.

[0073] In an embodiment, the method further comprises the step of mixing the fermentation-based binder with a different material, preferably aggregates. When the binder is mixed with the different material, it is referred to as a composite material.

[0074] In an embodiment, the step of mixing the substrate and the fungus is performed within a range of -20 to 75°C, preferably -10°C to 60°C, preferably -5 to 45°C, preferably 0 to 25°C.

[0075] In an embodiment, the method further comprises the step of allowing the fungus of the mixture to digest the substrate in the range of 1 to 45 days. In an embodiment, the method further comprises the step of inactivating the mycelium by heating, freezing, adding a gas, removing the substrate, or by removing the fluid after applying the paving material.

[0076] In an embodiment, the method further comprises the step of dividing the binder into smaller particles, for example by blending of the binder, prior to the step of mixing the fermentation-based binder with aggregates. By dividing the binder into smaller particles, the desired particle size may be achieved, such that the binder may be able to grow into cracks and / or cavities of the aggregates and thereby increase a contact area between the binder and the aggregates.

[0077] In an embodiment, the method further comprises a step of liquid state fermentation of the fungus before mixing with substrate. In this way, growth of the fungus may be promoted, and / or the amount of fungus may be increased. The liquid state fermentation may be followed by solid state fermentation. The liquid from the liquid state fermentation may be used for wetting the substrate and / or aggregates to obtain a desired humidity of the binder, and / or the liquid may be drained off before mixing the fungus with the substrate to transition to solid state fermentation.

[0078] In liquid state binder fermentation the only solid present may be the fungus. Liquid state fermentation may be advantageous as the fungus yield may be higher than in solid state fermentation.

[0079] In an embodiment, liquid state fermentation is not followed by solid state fermentation. Liquid state fermentation may continue after mixing the binder with the different material, preferably aggregates, to form the composite material.

[0080] In an embodiment, the method further comprises the subsequent step of adding binder and / or organic substrate to an area of the previously deposited composite material. The area may for example be an area in need of repair or gaps between adjoining paving stones.

[0081] The method may be carried out in a batchwise manner by placing the mixture of the organic substrate and mycelium in a form so that the finished composite material takes on the shape of the form. Alternatively, the method may be performed in a continuous manner to form an endless length of composite material or according to a conveyor belt length.

[0082] These and other objects and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0083] Brief Description of Drawings

[0084] In the following description, embodiments of the invention will be described with reference to the schematic drawings, in which:

[0085] Fig. 1 shows a picture of a composite material according to an embodiment of the invention.

[0086] Fig. 2 shows a picture of packages comprising the fermentation-based binder according to the invention.

[0087] Fig. 3 shows a flowchart showing steps of the method for producing a fermentation-based binder according to an embodiment.

[0088] Fig. 4 shows a perspective view of the invention according to an embodiment;

[0089] Fig. 5 shows a perspective view of the invention according to an embodiment.

[0090] Description of Embodiments

[0091] Referring initially to Fig. 1, a composite material 20 comprising a fermentation-based binder 10 for use in paving material production is shown in a container 30. The binder 10 comprises an organic substrate 11 and a preselected fungus 12, which are not shown, configured to consume the substrate 11. The organic substrate 11 comprises a nutrient material capable of being digested by the fungus such that mycelium is grown. The binder 10 comprises fluids allowing the mycelium to grow. The fluids are water and air. The substrate of the binder comprises cavities, not shown here, in which the mycelium is grown into or through. In this embodiment, a filamentous fungus is used. The binder has grown through a cavity spanning the length of the material. The mycelium has filled out the cavity in which it has grown. The substrate comprises a sawmill waste product, such as sawdust, hay, lupine, biorefinery grass fibers, compost and / or manure.

[0092] The binder is produced by providing a container 30 with an internal space containing air. The internal space in the container is sanitized. The organic substrate comprising the nutrient material is provided in the container. The preselected fungus is provided in the container, and the fungus and the substrate are mixed, such that the fungus can digest the nutrient material, and mycelium is grown. The fungus and the substrate is in this embodiment mixed in a substantially homogenous manner. The binder has been mixed with aggregates 21 and is referred to as a composite material 20. The composite material 20 was in this embodiment cultivated at 28°C for 19 days in a not shown incubator. The composite material 20 may be cultivated for 14 days to 28 days. The composite material 20 comprises 10 wt.%% binder, 5 wt.% water and 85 wt.% bitumen-based recycled aggregates. The composite material 20 is compressed slightly to improve the material properties. The container 30 is made of plastic, however other suitable materials are also possible. The container 30 is sanitized before adding the composite material 20 to the container. In this embodiment, the composite material comprises an additive in the form of rapeseed oil. The additive is added after mixing the binder with the aggregates. The additive may additionally or alternatively be added before the binder is mixed with the aggregates.

[0093] The composite material 20 is used in a method for constructing a paved area. The method comprises the steps of providing the composite material 30, and disposing the composite material 20 onto a first layer of a base. The first layer provides support to the composite material and acts as a protective layer. The method further comprises the step of surface evening the composite material by compression and / or rolling of the composite material, such that the composite layer has a substantially uniform thickness to prevent big holes in the paved area.

[0094] Referring now to Fig. 2, four packages 40 comprising the fermentation-based binder are shown. Each binder 10 is produced using different fungi; Pleurotus os- treatus, Fames fomentarius, Ganoderma lucidum, and Trametes versicolor, respectively. The binders 10 are produced using fluids comprising air and water. The organic substrate and nutrient material is in this embodiment sawdust. The package 40 comprises a container with an internal space and a sanitized internal space accommodating the binder. The substrate comprises cavities 13, in which the mycelium may grow. The container is a plastic bag with a HEPA filter and an air inlet 31.

[0095] Referring to Fig. 3, a flowchart showing an embodiment of the invention describing details of the method of preparing the fermentation-based binder is provided. In the embodiment of Fig. 3, the method includes the optional steps of providing a fungal spawn / mycelium separately by the following steps:

[0096] • Providing an inoculum, preferably a liquid inoculum, of a fungal strain. This may be provided by adding a slice of mycelium from an agar plate to a nutrient rich medium, preferably a liquid medium, consisting of autoclaved demineralized water, malt extract, yeast extract, and / or trace elements;

[0097] • Propagating the inoculum at 25°C under constant rotation using a magnet stirrer or a liquid fermenter. This temperature has proven specifically advantageous, however other temperatures may also work. Aseptic techniques may be used to ensure a sanitized environment in which the inoculum can grow. Such a sanitized environment may include a sterile bag for solid state fermentation or a flask for liquid state fermentation comprising a High Efficiency Particulate Air (HEPA) filter;

[0098] • Alternatively or additionally, providing an inoculum comprising mycelium from an agar plate, which has been sliced into smaller particles between 1 mm x 1 mm and 1 cm x 1 cm and using it directly in the below steps. This step may be performed instead of the above- mentioned steps;

[0099] • Autoclaving the amount of nutrient medium required to make the amount of fungal spawn desired, 7 days after the inoculum has been produced. The step of autoclaving may also be carried out more than or less than 7 days after producing the inoculum; • Placing the autoclaved nutrient medium in a sanitized environment, such as a sterile work environment, e.g. a laminar air flow (LAF) bench, until the nutrient medium has been cooled down to approximately 40°C;

[0100] • Adding an amount of the nutrient medium and mycelium to a container. Any amount of the nutrient medium and mycelium may be added to the container, ranging from 0.5 wt.% of the size of the container to 99 wt.% of the size of the container preferably allowing some headspace;

[0101] • Optionally, the container may be substantially closed using a HEPA filter, which allows air to flow into the container.

[0102] • The mixture of nutrient medium and mycelium may at any point be shook to ensure full coverage of the inoculum, to break up the mycelium, and / or to check for contaminations.

[0103] • Placing the container containing the mixture of nutrient medium and mycelium in an incubator at 28°C. In this embodiment, the relative humidity in the incubator is between 50 wt.% and 90 wt.%. When the mixture of medium and mycelium show colonization of mycelium, the fungal spawn / mycelium may be ready for being mixed with an organic substrate. Colonization may be visible as white fluffy growth covering the mixture.

[0104] • Storing the fungal spawn / mycelium between 2 to 5°C until needed. If necessary one or more of the above-mentioned steps may be repeated.

[0105] In the embodiment of Fig. 3, the method comprises the following steps:

[0106] • Providing an organic substrate comprising a nutrient material in a container;

[0107] • Providing the preselected fungus in the container. This may be the fungal spawn;

[0108] • Optionally adding water to the container to reach a moister content of 20 wt.% to 95 wt.%, preferably 50 wt.% to 90 wt.%, in the organic substrate.

[0109] • Sanitizing the organic substrate by heating the environment to the range of 90°Cto 140°C for 40-240 minutes, preferably 20-30 minutes, with steam and / or pressure. In other embodiments, the step of sanitizing is performed for more than 240 minutes or less than 40 minutes. Other temperature ranges are also possible. The step of sanitizing may additionally or alternatively be performed by autoclaving, steaming, and / or UV radiation;

[0110] • Mixing the fungus with the organic substrate in a container, such as a biosource comprising sawdust from e.g. a pine tree and / or an oak tree, such that said fungus digests the nutrient material, and mycelium is grown. In this embodiment, 90 wt.% substrate is mixed with 10 wt.% mycelium, however other ratios are also possible, such as 80 wt.% organic substrate and 20 wt.% mycelium, or 99 wt.% organic substrate and 1 wt.% mycelium. In this embodiment, the sawdust constitutes the nutrient material. The fungal spawn and the substrate is mixed substantially homogenously, such that the fungal spawn is dispersed in the substrate. The fungal spawn and the substrate are mixed in the range of 15°C to 30°C, however other temperature ranges are also possible;

[0111] • Placing the container comprising the mixture of fungal spawn and organic substrate in an incubator, such that the fungal spawn may grow at 28°C for 7 to 28 days. Within this time range, the container may optionally be shaken to break up the grown mycelium and check for contaminations. When the substrate shows colonization of the fungal spawn / mycelium, which may also be visible as white fluffy growth covering the substrate, the binder may be ready for use;

[0112] • Storing the binder at 2-5°C until needed

[0113] If the organic substrate is polluted, contaminated, or in any other way spoiled, it may be discarded at any point. In an embodiment, the composite material comprises 3 wt.% a high nutrition substrate such as hulled barley, 10 wt.% sawdust, 10 wt.% mycelium, and 77 wt.% aggregates. The same kind of aggregates and / or different kind of aggregates may be used, such as tau, jelsa, gravel, and / or RAP.

[0114] In an embodiment, the composite material comprises 3 wt.% a high-nutri- tion substrate e.g. hulled barley, 9 wt.% saw dust, 10 wt.% mycelium, 78 wt.% aggregates.

[0115] In an embodiment, the composite material comprises 3 wt.% hulled barley, 9 wt.% saw dust, 10 wt.% mycelium, 80 wt.% aggregates.

[0116] In an embodiment, the composite material comprises 1.6 wt.% fungi spawn grown on hulled barley, 3.4 wt.% hydrated sawdust, 1.0 wt.% rapeseed oil and 94 wt.% aggregates.

[0117] In an embodiment, the composite material comprises 2,7 wt.% fungi spawn grown on hulled barley, 5.6 wt.% hydrated sawdust, 1.0 wt.% rapeseed oil and 90.7 wt.% aggregates.

[0118] In an embodiment, the composite material comprises 3.2 wt.% fungi spawn grown on hulled barley, 6.8 wt.% hydrated sawdust, 1.0 wt.% rapeseed oil and 89 wt.% aggregates.

[0119] In an embodiment, the composite material comprises 4 wt.% fungi spawn grown on hulled barley, 4 wt.% hydrated sawdust, 1.0 wt.% rapeseed oil and 79 wt.% aggregates.

[0120] In an embodiment, the composite material comprises 4 wt.% fungi spawn grown on hulled barley, 4 wt.% hydrated sawdust, and 80 wt.% aggregates.

[0121] In an embodiment, the composite material comprises 7 wt.% fungi spawn grown on hulled barley, 4.3 wt.% hydrated sawdust, and 88.7 wt.% aggregates.

[0122] In an embodiment, the composite material comprises 7 wt.% fungi spawn grown on hulled barley, 6 wt.% hydrated sawdust, and 87 wt.% aggregates.

[0123] In an embodiment, the composite material comprises 7 wt.% fungi spawn grown on hulled barley, 6 wt.% hydrated sawdust, 1.5 wt.% calcium sulphate (CaSO4), 3 wt.% calcium carbonate (CaCO3), and 82.5 wt.% aggregates. In an embodiment, the composite material comprises 8 wt.% fungi spawn grown on hulled barley, 16 wt.% hydrated sawdust, 1.0 wt.% rapeseed oil and 75 wt.% aggregates.

[0124] In an embodiment, the composite material comprises 8 wt.% fungi spawn grown on hulled barley, 16 wt.% hydrated sawdust, and 76 wt.% aggregates.

[0125] In an embodiment, the substrate comprises 50 wt.% sawdust and 50 wt.% hay.

[0126] In an embodiment, the substrate comprises 25 wt.% sawdust, 25 wt.% compost and 50 wt.% hay.

[0127] In an embodiment, the substrate comprises 50 wt.% sawdust and 50 wt.% lupine.

[0128] In an embodiment, the substrate comprises 50 wt.% sawdust and 50 wt.% biorefinery grass fibers.

[0129] Referring now to Fig. 4, a schematic figure of a composite material 20 in a container 30 is shown. The container of the package comprises an air inlet in the form of a HEPA filter for allowing gas exchange. The container is made from a flexible material, allowing the container to stretch or expand when the bindergrows substantially in size and thus does not absolutely restrict it. In this embodiment, the container is a plastic bag. In some embodiments, the container comprises a flexible material and a non-flexible material.

[0130] Referring to Fig. 5, an embodiment, in which the container of the package has a length and a width, is shown. The length is greater than the width of the container.

[0131] The container has perforated holes 34 and comprises a tube 33 to allow air exchange, such that the container is not closed. In other embodiments, the container comprises only a filter or is perforated. The container is made of metal. The heat and gas exchange takes place through the perforated sides of the container and through the filter, while the mycelium colonizes the organic substrate.

Claims

P A T E N T C L A I M S1. A fermentation-based binder for use in paving material production, comprising: an organic substrate, a preselected fungus configured to consume the substrate, wherein the organic substrate comprises a nutrient material, said nutrient material being capable of being digested by said fungus such that mycelium is grown, and a fluid allowing the mycelium to grow.

2. The fermentation-based binder for use in paving material production according to claim 1, wherein the substrate comprises at least one cavity, allowing the mycelium to grow into or through the at least one cavity.

3. The fermentation-based binder for use in paving material production according to any one of the preceding claims, wherein the fungus is a filamentous fungus.

4. The fermentation-based binder for use in paving material production according to any one of the preceding claims, wherein the fungus is a basidiomycete, preferably a white-rot fungus and / or a brown-rot fungus.

5. The fermentation-based binder for use in paving material production according to any one of the preceding claims, wherein the organic substrate comprises an agriculture waste product, forest waste product, liquid and / or solid biorefinery products, paper pulp, liquid residues comprising sugar, food production side streams and / or agricultural production side streams.

6. The fermentation-based binder for use in paving material production according to any one of the preceding claims, wherein the fluid comprises air and / or water.

7. The fermentation-based binder for use in paving material production according to any one of the preceding claims, wherein the fermentation-based binder comprises a living fungus.

8. A package for use in paving material production comprising thefermentation-based binder of claim 1; wherein the package further comprises a container with an internal space, the container comprising a sanitized environment accommodating the binder, wherein the substrate comprises at least one cavity, in which the mycelium can grow.

9. A package for use in paving material production according to claim 8, wherein the container comprises a flexible material and / or plastic, wood, metal, steel, a paper-based material, plant fibers, textile fibers, gypsum, clay, rubber, spray coating, and / or a concrete material.

10. A package according to claim 8 or 9, wherein the container has a length and a width, wherein the length is greater than the width of the container.

11. A composite material comprising the fermentation-based binder of claim 1 and a different material, preferably aggregates.

12. The composite material according to claim 11, wherein the binder constitutes 1 wt.%, 5 wt.%, 10 wt.%, 15 wt.%, 20 wt.%, 25 wt.%, 30 wt.%, 35 wt.%, 40 wt.% or 45 wt.% of the composite material.

13. A method of providing a fermentation-based binder comprising the steps of providing a container with an internal space containing a fluid, preferably air and / or water, the internal space in the container being sanitized; providing an organic substrate comprising a nutrient material in the container; providing a preselected fungus in the container, said fungus being capable of digesting the nutrient material, mixing the fungus with the substrate, such that said fungus digests the nutrient material and mycelium is grown.

14. The method according to claim 13, wherein the fungus and the substrate are mixed until a homogenous binder is achieved, where the fungus is substantially dispersed in the substrate.

15. The method according to claim 13 or 14, wherein the method furthercomprises the step of mixing the fermentation-based binder with a different material, preferably paving material aggregates.

16. The method according to any one of claims 13 to 15, wherein the step of mixing the substrate and the fungus is performed within a range of -20°C to 75°C, preferably -10°C to 60°C, preferably -5 to 45°C, preferably 0 to 30°C.

17. The method according to any one of claims 13 to 16, further comprising the step of dividing the binder into smaller particles, preferably by blending, shredding, grinding, pulverizing, and / or chopping of the fermentation-based binder, prior to the step of mixing the fermentation-based binder with aggregates.

18. A method for constructing a paved area, comprising the steps of providing the composite material of anyone of claims 11 to 12; disposing the composite material onto a first layer of a base; surface evening the composite material by compression or rolling of the composite material, such that the composite layer has a substantially uniform thickness.

19. The method according to claim 18, further comprising the subsequent step of adding binder and / or organic substrate to an area of the previously deposited composite material.

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