Insulation

Abstract

A method for preparing a mycelium coated structure that comprises the steps of providing a porous scaffold, treating the porous scaffold, surface functionalising said scaffold with a functional group

Description

The present invention relates to a mycelium coated porous structure which is used as an insulation or packaging material. It has been identified that the mycelium of fungi can be used in block formation to prepare insulation and packaging materials. As fungi grow their hyphae spread throughout the nutrient solution as they consume the nutrients therein. During this process an interconnected web of fungal cells create a strong mat structure (mycelium) which will char but will not melt nor ignite. The advantage of insulation and packaging materials made of fungi is that it is fully biodegradable and renewable. Provided fungi are given the correct nutrients they will grow very successfully in a short time. Accordingly, this leads to low cost production. Advantageously, the production of mycelium-based insulation is carbon negative. To date blocks of mycelium-based insulation and packaging material have been produced. However, not all situations are suitable for the use of blocks of insulation or packaging material. For example, awkwardly shaped items or retro-fitting insulation into cavities within, for example, buildings. Accordingly, there is a need for an environmentally friendly form of insulation which can be used in a variety of situations. According to the present invention there is provided a method for preparing a mycelium coated structure comprising the following steps: a) providing a porous scaffold; b) treating the porous scaffold by i) surface functionalising said core with a functional group via silanization; ii) optionally attaching a linker molecule to the functional group on the functionalised scaffold; and iii) attaching a carbohydrate and / or an amino acid molecule to the functional group or the linker molecule, if present; and c) placing the treated porous scaffold into a fungus containing solution to create a mycelium coated structure. The fungus within the solution will grow around and through the porous scaffold using the carbohydrate and / or amino acid as a nutrient source and create a mycelium which is a network of fungal threads or hyphae. The scaffold, which forms a core structure, can be of any form provided that there is an internal structure through which the mycelium can grow. For example, the scaffold can be in the form of a bead or chip. The optional use of a linker makes the surface of the porous scaffold more reactive to the carbohydrate and allows for a greater number of carbohydrates to be bound to the surface. Thereby increasing the food source available to the mycelium. The placing into a fungus solution can involve placing the scaffold into a solution already containing fungus or placing the scaffold into a solution then adding in the selected fungus. The solution may contain additional nutrients for growth of a mycelium or all the necessary nutrients can be provided on the scaffold. Conveniently the porous scaffold or core is in the form of a bead or a chip such as a clay pebble or a brick chip. It should be noted that the porous scaffold can be any shape regular or irregular and the terms "bead" and "chip" used herein are not intended to suggest any particular shape. Examples of regular shapes which could be used are cylinders, spheres, cones, cubes, prisms, tetrahedron, cuboid, pyramidal, dodecahedron, icosahedron or octahedron. This list should not be considered exhaustive. Conveniently the porous scaffold is of a form which allows 5mm to 500mm mycelium growth while still maintaining its structure when dry and, therefore, for example allowing the insulation product to be a loose fill. Conveniently the bead such as a clay pebble has a diameter of 5 mm to 400mm. Conveniently the chip has a largest length of 5 to 20 mm. Conveniently, 5 to 13mm. Conveniently, the porous scaffold or core has a tunable porosity. The tunable porosity allows the mycelium coated structure to have defined individual pieces and at the same time maintaining the defined structure during use, which allows the mycelium coated structure to be used as loose fill insulation. Further, conveniently pores in the core are greater than 200nm so that the mycelium can fit inside the pores but less than 2000 nm so other microbial growth which could cause contamination will find the growth conditions prohibitive. Conveniently, the porous core is formed from a material selected from alumina, silica, quartz, hafnia, zirconia, functional materials, such as titania and cerium (IV) oxide, ceramic blends and silicon. Conveniently, the porous core is formed from silica. A "functional material" as herein used has catalytic properties which can facilitate biological processes in symbiosis with mycelium. Conveniently, the functional group is selected from an amine, an aldehyde including a dialdehyde, a thiol, an acyl chloride including a diacyl chloride, a ketone, an epoxy, a carboxylic group or a halogen group. Conveniently, the functional group is an amine, for example, (3-aminopropyl)triethoxysilane. Conveniently, the functional group is an acyl chloride such as succinyl chloride. Conveniently, the method further comprises attaching more than one linker molecule. Conveniently, the linker molecule is either a straight chain of carbon atoms with a linker functional group at either end ora branched carbon atom structure with a linker functional group at each end. Conveniently, the linker functional group is different at each end of the carbon atom chain or branched carbon atom structure. This would allow for a particular orientation of the linker molecule. Alternatively, the linker group is the same at each end of the carbon atom chain or at the end of at least some of the ends of the branched carbon atom structure. In this regard, the use of the same functional group in the linker molecule reduces self-reaction of the linker molecules. Further, if the surface of the porous core has the same reactivity trends as the carbohydrate and / or amino acid then it streamlines the production of the structure. For example, porous structure with an amine based surface can be used so that the porous structure surface has the same reactivity trends as the alcohol groups on the carbohydrates attached to the functional group or linker molecule. Conveniently, the branched carbon atom structure has in the range of 2 to 4 branches. Conveniently, there are in the range of 1 to 5 carbon atoms before branching in the branched carbon atom structure. Conveniently, the straight chain of carbon atoms is in the range of 1 to 6 atoms. Conveniently, 3 to 4 carbon atoms. It is important to allow enough freedom of movement of the linker to react without making the surface of the scaffold oily / hydrophobic. In this respect, if the chain is too long, then it may affect the properties of the bead but shorter chains may not react in a favourable manner. Conveniently, the linker molecule is selected from succinyl chloride, 1,3-diaminopropane and 1,4-butanedithiol. Conveniently, the carbohydrate is selected from fructose, glucose, saccharose, maltose, dextrose, pectin, lactose, xylose, starch, dextrin, hemicellulose or derivatives thereof such as short chained hemicellulose molecules, potato dextrose or cornstarch-based products such as amylopectin or amylose. Conveniently, it is an amino acid which is attached to the functional group. The amino acid will increase the nitrogen content and allow the carbon / nitrogen ratio to be optimised for mycelium growth. Conveniently the fungus containing solution is either a solution containing at least one nutrient for growth of fungi and at least one piece of agar with fungus cultivated thereon, or a liquid fungus containing culture. Conveniently, the fungus is a Dikarya. Conveniently, the fungus is selected from Agaricomycetes, Agaricostilbomycetes, Atractiellomycetes, Bartheletiomycetes, Classiculomycetes, Cryptomycocolacomycetes, Cystobasidiomycetes, Dacrymycetes, Exobasidiomycetes, Malasseziomycetes, Microbotryomycetes, Mixiomycetes, Moniliellomycetes, Pucciniomycetes, Spiculogloeomycetes, Tremellomycetes, Tritirachiomycetes, Ustilaginomycetes, Wallemiomycetes Taphrinomycotina, and Pezizomycotina. Conveniently the fungus is selected from a single subdivision. In this regard, taxonomically different fungus may compete with one another which would not be beneficial for the present invention. Further, close genetic relatives may mate and mutate which could lead to issues with the final product. Conveniently, the treated porous scaffold is in the fungus containing solution for in the range of 4 to 10 days. Conveniently, 5 to 7 days. The exact time required for sufficient mycelium growth will depend upon the fungus chosen. Conveniently, the method further comprises removing the mycelium coated structure when a critical diameter is reached. The mycelium coated structure can be removed using a size exclusion method of separation. Conveniently, the critical diameter is in the range of about 0.5 mm to about 4cm. Conveniently, the method further comprises drying the removed mycelium coated structure. Conveniently, the drying step takes place at a temperature in the range of 40 to 85°C. For example, at a temperature in the range of 50 to 75° C. Conveniently, the method further comprises coating the mycelium coated structure. Conveniently, the coating has water resistance, fire resistance, vapour permeability, acoustic insulation, thermal and / or mould resistance properties. It is beneficial if the coating maintains good vapour permeability along with thermal and acoustic insulation properties. According to a further aspect of the present invention there is provided an insulation bead obtainable from the method described herein. According to a yet further aspect of the present invention there is a provided an insulation bead with a porous scaffold wherein the porous scaffold is filled with and coated in mycelium. In the present invention "filled with" and "coated in" merely mean that there is at least some hyphae growth through and on the porous scaffold. Conveniently, at least 50% of the surface of the porous scaffold will have hyphae growth. Conveniently, the hyphae growth will be over at least 75% of the surface of the porous scaffold. According to another aspect of the present invention there is a provided a porous scaffold with a functionalised surface wherein a functional group on the functionalised surface is linked to at least one carbohydrate or amino acid molecule and wherein the porous scaffold has mycelium grown thereon. The link between the functionalised surface and the carbohydrate or amino acid molecule may be direct or through a linker molecule which is described herein. The aspects of the invention described above in relation to the method also relate to the above identified product aspects of the invention (i.e. the insulation bead or porous scaffold). It will be understood that various changes and modification to the present invention described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its advantages. All numerical figures given above in respect of any aspect of the invention are approximate figures and should be considered to cover ±20% of the value given. For example, the mycelium growth given as 5mm to 500mm should be considered to include 4mm to 600mm. The invention will now be particularly described by way of example with reference to the accompanying figures in which: Figure 1A shows a diagram of the porous structure of the present invention (A: surface of the myceliated bead, B - porous solid material, for example, ceramic, Si, SiO2, biomass, TiO2, AI2O3, with a functional surface, C- mycelium growing inside pore structure. Figure IB shows a bead with an exposed porous core which can be used in the present invention. Figure 2 shows a reaction vessel containing aqueous carbohydrate layer (bottom) and the organic top layer with the majority of the beads. Figure 3A shows mycelium growth after 2 days Figure 3B shows mycelium growth after 7 days. Example 1 The surface of the clay was first prepared by cleaving the Hydroton to expose the porous interior before cleaning using isopropyl alcohol and deionised water (see Figure IB). The Hydroton was then dried in the dehydrator at 75°C for 4 hours. 128.51g of the cleaned and cleaved Hydroton balls were then combined with 120 mL of anhydrous n-Hexane (as received) before the dropwise addition of 3-aminopropyl trimethoxysilane (3 mL, 1.28210-2 mol) under gentle agitation. The reaction was allowed to proceed for 5 hrs before the Hydroton balls were filtered and dried. After being dried a 72.66 g portion of the Hydroton balls were combined with the hexane from the last reaction and succinyl chloride (0.8 mL, 7.2510-3 mol) was added dropwise and the reaction mixture was agitated over 2 hrs. A concentrated solution of potato dextrose (1.22 g in 50 mL of water was added) was then added to the reaction mixture. This led to the formation of an aqueous and organic layer, where the sugar is held in the aqueous layer and the hexane sits above this, some of the Hydroton balls floated in the hexane, organic, layer but mostly they sat at the bottom in the aqueous sugar solution (see Figure 2). The reaction mixture was agitated for 3 hrs at a temperature of around 50 °C. After this the Hydroton balls were filtered, washed in deionised water, and dried in the dehydrator at 75°C for 2 hours. The treated Hydroton (25.45 g) balls were placed in a liquid media broth containing yeast extract and and potato dextrose. These mixtures were then held at 30 °C in a grow tent 7 days. After this period a disc of mycelium leather could be observed with Hydroton balls bound into it (see Figures 3A and 3B).

Claims

1. A method for preparing a mycelium coated structure comprising the following steps: a) providing a porous scaffoldb) treating the porous scaffoldi) surface functionalising said scaffold with a functional group via silanization;ii) optionally attaching a linker molecule to the functional group on the functionalised scaffold; andiii) attaching a carbohydrate and / or a amino acid to the functional group or the linker molecule, if present; andc) placing the treated porous scaffold into a fungus containing solution to create a mycelium coated structure.

2. A method according to claim 1 wherein the porous scaffold is in the form of a bead or a chip.

3. A method according to claim 2 wherein the bead has a diameter in the range of 0.5cm to 4cm.

4. A method according to claim 2 wherein the chip has a size of 5 to 20 mm.

5. A method according to any preceding claim wherein the porous scaffold has a tunableporosity.

6. A method according to any preceding claim wherein the porous scaffold is formed from a material selected from alumina, silica, quartz, hafnia, zirconia, functional materials, such as titania and cerium (IV) oxide, ceramic blends and silicon.

7. A method according to any preceding claim wherein the functional group is selectedfrom an amine, an aldehyde, a thiol, an acyl chloride, a ketone, an epoxy, a carboxylic groupor a halogen group.

8. A method according to any preceding claim wherein the functional group is an amine.

9. A method according to any preceding claim further comprising attaching more thanone linker molecule.

10. A method according to any preceding claim wherein the linker molecule is either a straight chain of carbon atoms with a linker functional group at either end or a branched carbon atom structure with a linker functional group at each end.

11. A method according to claim 10 wherein the linker functional group is different at each end of the carbon atom chain or branched carbon atom structure.

12. A method according to claim 10 wherein the linker functional group is the same at each end of the carbon atom chain or at the end of at least some of the ends of the branched carbon atom structure.

13. A method according to any of claims 10 to 12 wherein the branched carbon atom structure has in the range of 2 to 4 branches.

14. A method according to any of claims 10 to 13 wherein there are in the range of 1 to 5 carbon atoms before branching in the branched carbon atom structure.

15. A method according to any of claims 10 to 12 wherein the straight chain of carbon atoms is in the range of 1 to 5 carbon atoms.

16. A method according to claim 12 wherein the linker molecule is selected from succinyl chloride, 1,3-diaminopropane and 1,4-butanedithiol.

17. A method according to any preceding claim wherein the carbohydrate is selected from fructose, glucose, saccharose, maltose, dextrose, pectin, lactose, xylose, starch, dextrin, hemicellulose or derivatives thereof.

18. A method according to claim 16 wherein the carbohydrate is selected from potato dextrose, amylopectin or amylose or derivatives thereof.

19. A method according to any preceding claim wherein the fungus containing solution is either a solution containing at least one nutrient for growth of fungi and at least one piece of agar with fungus cultivated thereon, or a liquid fungus containing culture.

20. A method according to any preceding claim wherein the fungus is a Dikarya.

21. A method according to claim 20 wherein the fungus is selected from Agaricomycetes, Agaricostilbomycetes, Atractiellomycetes, Bartheletiomycetes, Classiculomycetes, Cryptomycocolacomycetes, Cystobasidiomycetes, Dacrymycetes, Exobasidiomycetes, Malasseziomycetes, Microbotryomycetes, Mixiomycetes, Moniliellomycetes, Pucciniomycetes, Spiculogloeomycetes, Tremellomycetes, Tritirachiomycetes, Ustilaginomycetes, Wallemiomycetes Taphrinomycotina, and Pezizomycotina.

22. A method according either claims 20 to 21 wherein the fungus is selected from a single subdivision.

23. A method according to any preceding claim wherein the treated porous scaffold is in the fungus containing solution for in the range of 4 to 10 days.

24. A method according to any preceding claim wherein the method further comprises removing the mycelium coated structure when a critical diameter is reached.

25. A method according to claim 24 wherein the critical diameter is in the range of about 0.5 cm to about 4cm.

26. A method according to either claim 24 or 25 wherein the method further comprises drying the removed mycelium coated structure.

27. A method according to claim 26 wherein the drying step takes place at a temperature in the range of 40 to 85°C.

28. A method according to either claim 26 or 27 wherein the drying step takes place at a temperature in the range of 50 to 75° C.

29. A method according to any of claims 24 to 28 wherein the method further comprises coating the mycelium coated structure.

30. A method according to claim 29 wherein the coating has water resistance, fire resistance, vapour permeability, acoustic insulation, thermal and / or mould resistance properties.

31. An insulation bead obtainable from the method according to claims 1 to 30.

32. An insulation bead with a porous scaffold wherein the porous scaffold is filled with and coated in mycelium.

33. A porous scaffold with a functionalised surface wherein a functional group on the functionalised surface is linked to at least one carbohydrate or amino acid molecule and wherein the porous scaffold has mycelium grown thereon.

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