Bio-based leather alternatives

Abstract

The present invention relates to a bio-based leather substitute material comprising the reaction product of a protein extract derived from brewer's spent grains or distiller's spent grains and a crosslinking agent. The invention also includes constructs and articles formed therefrom.

Description

[Technical Field]

[0001] The present invention relates to bio-based leather substitute materials that provide a sustainable, non-synthetic alternative to animal-derived leather. [Background technology]

[0002] Animal-derived leather is resource-intensive and cruel to animals. However, alternative products, such as synthetic leather, are typically composed of plastic. These alternative products are not only difficult to process, but also non-biodegradable, contributing to microplastic pollution.

[0003] Other bio-based alternatives have also been explored recently, but these typically pose significant scaling challenges due to the intensive growth of feedstocks, such as cultured fungi.

[0004] It is therefore desirable to provide a sustainable, non-synthetic leather alternative that mimics the behavior of animal-derived leather and can be produced by an easily scalable manufacturing process. Summary of the Invention

[0005] According to a first aspect of the present invention, there is provided a bio-based leather substitute material comprising the reaction product of a protein extract derived from Brewer's Spent Grain or Distiller's Spent Grain and a crosslinking agent.

[0006] According to a second aspect of the present invention, there is provided a bio-based leather substitute material comprising brewer's spent grain or distiller's spent grain containing a protein, a cross-linking agent, and isolated algal polysaccharides or salts thereof.

[0007] According to a third aspect of the present invention, there is provided a construct comprising two or more layers of bio-based leather substitute material according to the first aspect of the present invention; or a bio-based leather substitute material according to the first aspect of the present invention and a scaffold support.

[0008] According to a fourth aspect of the present invention, there is provided a construct comprising two or more layers of bio-based leather substitute material according to the second aspect of the present invention; or a bio-based leather substitute material according to the second aspect of the present invention and a scaffold support.

[0009] According to a fifth aspect of the present invention, there is provided an article formed from a bio-based leather substitute material according to the first aspect of the present invention; or a construct according to the third aspect of the present invention.

[0010] According to a sixth aspect of the present invention, there is provided an article formed from a bio-based leather substitute material according to the second aspect of the present invention; or a construct according to the fourth aspect of the present invention.

[0011] According to a seventh aspect of the present invention, there is provided a bio-based leather substitute material according to the first aspect of the present invention, wherein the bio-based leather substitute material is produced by a method comprising providing a protein extract derived from brewer's spent grains or distiller's spent grains, combining with a cross-linking agent, and forming the bio-based leather substitute material.

[0012] According to an eighth aspect of the present invention, there is provided a method for producing a bio-based leather substitute material according to the first aspect of the present invention, the method comprising extracting a protein from brewer's spent grain or distiller's spent grain. providing a material, combining with a crosslinking agent, and forming a bio-based leather substitute material.

[0013] According to a ninth aspect of the present invention, there is provided a bio-based leather substitute according to the second aspect of the present invention, wherein the bio-based leather substitute is produced by a method comprising the steps of: subjecting isolated algal polysaccharides or salts thereof to a heat treatment; combining protein-containing brewer's spent grains or distillers' grains with a cross-linking agent; and forming the bio-based leather substitute.

[0014] According to a tenth aspect of the present invention, there is provided a method of producing a bio-based leather substitute material according to the second aspect of the present invention, the method comprising the steps of subjecting isolated algal polysaccharides or salts thereof to a heat treatment; combining protein-containing brewer's spent grains or distillers' grains with a cross-linking agent; and forming the bio-based leather substitute material.

[0015] According to an eleventh aspect of the present invention, there is provided the use of brewer's spent grain or distiller's spent grain in the manufacture of a bio-based leather substitute material according to the first aspect of the present invention.

[0016] According to a twelfth aspect of the present invention, there is provided the use of brewer's spent grain or distiller's spent grain in the manufacture of a bio-based leather substitute material according to the second aspect of the present invention.

[0017] According to a thirteenth aspect of the present invention, there is provided a bio-based leather substitute material comprising a protein extract derived from brewer's spent grains or distiller's spent grains and a plasticizer.

[0018] According to a fourteenth aspect of the present invention, there is provided a construct comprising two or more layers of bio-based leather substitute material according to the thirteenth aspect of the present invention; or a bio-based leather substitute material according to the thirteenth aspect of the present invention and a scaffold support.

[0019] According to a fifteenth aspect of the present invention, there is provided an article formed from a bio-based leather substitute material according to the thirteenth aspect of the present invention; or a construct according to the fourteenth aspect of the present invention.

[0020] According to a sixteenth aspect of the present invention, there is provided a bio-based leather substitute material according to the thirteenth aspect of the present invention, the bio-based leather substitute material being produced by a method comprising providing a protein extract derived from brewer's spent grains or distiller's spent grains, combining with a plasticizer, and forming the bio-based leather substitute material.

[0021] According to a seventeenth aspect of the present invention, there is provided a method of producing a bio-based leather substitute material according to the thirteenth aspect of the present invention, the method comprising providing a protein extract derived from brewer's spent grains or distiller's spent grains, combining with a plasticizer, and forming the bio-based leather substitute material.

[0022] According to an eighteenth aspect of the present invention, there is provided the use of brewer's spent grain or distiller's spent grain in the manufacture of a bio-based leather substitute material according to the thirteenth aspect of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] Detailed Description It has been surprisingly and advantageously discovered that the bio-based leather substitute material according to the present invention provides a sustainable, non-synthetic alternative to animal-derived leather. This novel material is formed using brewer's grain, an abundant by-product of the brewing industry, or distiller's grain, an abundant by-product of ethanol production. Thus, production of the bio-based leather substitute material can leverage existing supply chains (e.g., breweries or ethanol distilleries) and utilize widely available, low-cost alternatives. It utilizes low-cost waste materials.

[0024] The bio-based leather substitute according to the present invention is plastic-free, fully biodegradable and mimics the properties of animal-derived leather, such as softness and feel, and can therefore be advantageously used as a non-synthetic alternative to animal-derived leather, for example in the fashion, textile, packaging and furniture industries.

[0025] It is particularly surprising and advantageous that brewer's spent grains or distillers' grains, and protein extracts derived therefrom, can be used to produce the bio-based leather substitute material according to the present invention.

[0026] Brewer's grains or distillers' grains are not pure grains but waste materials that are unwanted by-products of beer or ethanol production. Before being used in the present invention, these grains have already undergone very intensive brewing or distillation processes. As a result of such intensive processing, brewer's grains or distillers' grains contain a variable and potentially unpredictable mixture of components, and there is no guarantee that the proteins remaining in the brewer's grains or distillers' grains are not reparably damaged. During intensive processing, protein degradation, typically hydrolysis, occurs, which shortens the protein chains and reduces their uniformity, potentially rendering them unsuitable for further processing or use. This varies from batch to batch. Furthermore, brewer's grains or distillers' grains are not easy to handle, especially in the form obtained from breweries, distilleries, or ethanol biofuel plants. They are moist biomass that is highly susceptible to decomposition and the formation of undesirable bacterial and / or fungal substances within.

[0027] Therefore, it is extremely surprising and advantageous to be able to produce a bio-based leather alternative from brewer's or distiller's grains, given that the starting materials are highly unpredictable. Brewer's or distiller's grains typically contain multiple proteins, each with different properties. There are many considerations.

[0028] "Leather substitute" means a material that can be used as a substitute for animal-derived leather. "Bio-based" means derived from plants and other renewable agricultural resources, as opposed to non-renewable raw materials such as petroleum. The bio-based leather substitute of the present invention is a bio-based material suitable for use as a leather substitute.

[0029] As used herein, the term "brewer's grains or distillers' grains" refers to a protein-containing grain by-product of beer (brewery) or spirits (distillery, e.g., whiskey) production, where grains are used in the fermentation process. Distillers' grains may also refer to a protein-containing grain by-product of ethanol biofuel production. Distillers' grains typically consist of barley grain by-products and contain proteins, lignin, lipids, and cellulose, as well as optional by-products of other grain components introduced during the brewing process. Distillers' grains may also contain additional by-products as a result of the processes they undergo, such as excess sugars that are broken down by bacterial and / or fungal growth within the grains, and / or enzymes such as amylases that can produce more sugars for use in the brewing process. Distillers' grains typically consist of rice, wheat, rye, and / or corn grain by-products and typically contain proteins, lignin, lipids, and cellulose, as well as optional by-products from other grain components introduced during the fermentation process. Distiller's grains may also contain additional by-products as a result of the processes they have undergone, such as insoluble fiber components and / or excess sugars that can be decomposed by bacterial and / or fungal growth within the distiller's grains, and / or enzymes such as amylases that can be used in the distillation process to produce even more sugars. Typically, brewer's grains or distiller's grains may contain 5-40% protein by weight, preferably 5-35% protein by weight, or 10-30% protein by weight, or 12-30% protein by weight, on a dry weight basis. Typically, brewer's grains or distiller's grains may contain 5-40% protein by weight, preferably 5-35% protein by weight, or 10-30% protein by weight, or 12-30% protein by weight. Distillers' grains or spent grains may contain 5 to 40% by weight of lignin, preferably 11 to 32% by weight, on a dry weight basis. Typically, distillers' grains or spent grains may contain 1 to 15% by weight of lipids, on a dry weight basis. Typically, distillers' grains or spent grains may contain 10 to 80% by weight, for example, 20 to 60% by weight, preferably 23 to 60% by weight, of cellulose, on a dry weight basis. As used herein, the "cellulose" of distillers' grains or spent grains encompasses any hemicellulose and starch present in distillers' grains or spent grains. Preferably, at least 90% of the distillers' grains is a barley grain by-product. Distillers' grains or spent grains may be obtained directly from a brewery. Distillers' grains or spent grains may be obtained directly from a distillery or an ethanol biofuel plant. Distillers' grains or spent grains may be provided in either wet or dry form. Distillers grains include wet distillers grains (WDG) and dry distillers grains with solubles (DDGS).

[0030] The term "protein extract" refers to a protein composition extracted by solubilizing proteins from brewer's grains or distiller's grains. Without being bound by theory, the inventors believe that the protein extract has a different structure after extraction compared to when present in the brewer's grains or distiller's grains. The inventors hypothesize that the proteins in the protein composition are loosened and denatured during extraction. During production of the bio-based leather substitute material, the proteins can bond with each other to form a protein network and, if necessary, with other components of the bio-based leather substitute material. The protein extract may contain a complex mixture of proteins. As used herein, the term "protein extract" encompasses "protein isolate," which is a protein composition extracted from brewer's grains or distiller's grains by solubilizing proteins, then separated from one or more other components of the brewer's grains or distiller's grains, typically the insoluble component(s) of the brewer's grains or distiller's grains, and optionally further purified. The insoluble component may be insoluble grain husks. During the production of the bio-based leather substitute material, the protein extract or protein isolate may be present in solution or solid form.

[0031] Preferably, the protein extract in the bio-based leather substitute material according to the first aspect of the present invention is derived from brewer's spent grains.

[0032] The presence of the protein extract from brewer's spent grain or distiller's spent grain in the bio-based leather substitute material according to the first aspect of the present invention allows for the formation of a tough, flexible material with improved abrasion resistance, elasticity and hand feel.

[0033] The bio-based leather substitute material according to the first aspect of the present invention comprises a reaction product of a protein extract derived from brewer's spent grains or distiller's spent grains and a cross-linking agent. The reaction product is a cross-linked protein extract. It is also understood that the bio-based leather substitute material according to the first aspect of the present invention may comprise non-cross-linked protein extract and / or cross-linking agent, for example, excess protein extract and / or cross-linking agent.

[0034] Without being bound by theory, the inventors believe that brewer's grains or distillers' grains contain prolamins, which include hordeins, albumins, gliadins and glutelins.

[0035] Thus, the protein extract from brewer's or distiller's grains may comprise prolamins selected from hordeins, albumins, gliadins and / or glutelins, preferably hordeins.

[0036] The protein extract from brewer's spent grain or distiller's spent grain may be present in the bio-based leather substitute material according to the first aspect of the present invention in any suitable amount. , 6 to 90% by weight of protein extract, for example, 12 to 80% by weight of protein extract. When the protein extract derived from brewer's grains or distiller's grains is a protein isolate, the bio-based leather substitute material may contain 55 to 90% by weight of protein isolate, preferably 55 to 80% by weight of protein isolate. It is understood that this amount refers to all of the protein extract in the bio-based leather substitute material, whether cross-linked or not. When the protein extract derived from brewer's grains or distiller's grains is a protein extract but not a protein isolate, i.e., extracted from brewer's grains or distiller's grains but not separated and optionally not purified, the bio-based leather substitute material may contain 6 to 60% by weight of protein extract, preferably 12 to 50% by weight of protein extract, or 12 to 30% by weight of protein extract.

[0037] The bio-based leather substitute material according to the first aspect of the present invention may further comprise one or more other components (other than the protein extract) of brewer's spent grains or distiller's draught. For example, the insoluble component(s) of brewer's spent grains or distiller's draught. These components can be retained throughout the production of the bio-based leather substitute material after extraction of the proteins from brewer's spent grains or distiller's draught, and thus be present in the final bio-based leather substitute material. Alternatively, during the production of the bio-based leather substitute material according to the first aspect of the present invention, the protein extract may be separated and optionally purified from one or more other components of brewer's spent grains or distiller's draught, typically the insoluble component(s) of brewer's spent grains or distiller's draught. However, these one or more other components can be reintroduced into the production process as part of the bio-based leather substitute material or in other forms, such as a scaffold support, as described below. As used herein, the "insoluble component(s)" of brewer's grains or distiller's grains refers to the component(s) other than the protein extract that are insoluble in solutions such as water and / or alkaline solutions used for protein extraction.

[0038] The bio-based leather substitute according to the first aspect of the present invention may further comprise lignin, lipids, and / or cellulose. Accordingly, the bio-based leather substitute according to the first aspect of the present invention may comprise 2-32% by mass of lignin, preferably 2-26% by mass of lignin. The bio-based leather substitute according to the first aspect of the present invention may comprise 1-15% by mass of lipids, preferably 1-10% by mass of lipids. The bio-based leather substitute according to the first aspect of the present invention may comprise 15-60% by mass of cellulose, preferably 20-50% by mass of cellulose.

[0039] The bio-based leather substitute material according to the first aspect of the present invention may further comprise a protein extract derived from brewer's grains or distiller's grains and a protein isolate derived from brewer's grains or distiller's grains. In such cases, the bio-based leather substitute material according to the first aspect of the present invention may comprise 6 to 60% by mass of the protein extract and protein isolate, preferably 12 to 50% by mass of the protein extract and protein isolate.

[0040] The bio-based leather substitute material according to the first aspect of the present invention may further comprise an isolated algal polysaccharide or a salt thereof, preferably an isolated algal polysaccharide. One or more isolated algal polysaccharides or salts thereof may be used.

[0041] As used herein, "isolated algal polysaccharides" refers to polysaccharides extracted and separated from algae such as brown algae, red algae, and green algae, and optionally purified.

[0042] Suitable isolated algal polysaccharides include isolated algin, isolated fucoidan, isolated laminarin, isolated alginic acid, isolated agar agar, isolated carrageenan such as K-carrageenan, I-carrageenan or L-carrageenan, isolated ulvan, or Combinations thereof may be included, but are not limited to these. The isolated algal polysaccharides are anionic polysaccharides. Preferably, the isolated algal polysaccharides are K-calcium phosphate. isolated carrageenan, such as lageenan, or isolated agar agar, or a combination of both.

[0043] Salts of the isolated algal polysaccharides include ionic analogs of the isolated algal polysaccharides, for example, sodium or calcium salts such as sodium alginate or calcium alginate.

[0044] The presence of isolated algal polysaccharides in the bio-based leather substitute material according to the first aspect of the present invention allows for the formation of a stronger material with further increased tensile strength and increased tear strength. Without being bound by theory, the inventors believe that the isolated algal polysaccharides, when present in the bio-based leather substitute material, provide advantageous strength by forming tightly packed chains of polysaccharides with significant intermolecular bonds.

[0045] The isolated algal polysaccharides may be present in the bio-based leather substitute material according to the first aspect of the present invention in any suitable amount. The bio-based leather substitute material may comprise 4 to 50% by weight of isolated algal polysaccharides, for example 4 to 40% by weight of isolated algal polysaccharides.

[0046] According to a second aspect of the present invention, there is provided a bio-based leather substitute material comprising protein-containing brewer's or distiller's spent grains, a cross-linking agent, and an isolated algal polysaccharide or a salt thereof.

[0047] All features of the second aspect of the invention, as described below as preferred or optional, are applicable to all other aspects described herein, and likewise, all features of all other aspects described herein, whether preferred or optional, are applicable to the second aspect of the invention.

[0048] The isolated algal polysaccharide or salt thereof of the bio-based leather substitute material according to the second aspect of the present invention is as described above according to the first aspect of the present invention.

[0049] Suitable isolated algal polysaccharides include isolated algin, isolated fucoidan, isolated laminarin, isolated alginic acid, isolated agar agar, K-carrageenan, I-carrageenan, or L-carrageenan. Preferably, the isolated algal polysaccharide is an anionic polysaccharide. Preferably, the isolated algal polysaccharide is an isolated carrageenan such as K-carrageenan, or an isolated ulvan, or a combination thereof. lageenan, or isolated agar agar, or a combination of both.

[0050] Salts of the isolated algal polysaccharides include ionic analogs of the isolated algal polysaccharides, for example, sodium or calcium salts such as sodium alginate or calcium alginate.

[0051] The presence of isolated algal polysaccharides in the bio-based leather substitute material according to the second aspect of the present invention allows for the formation of a tough material with further increased tensile strength and increased tear strength. Without being bound by theory, the inventors believe that the isolated algal polysaccharides, when present in the bio-based leather substitute material, provide advantageous strength by forming tightly packed chains of polysaccharides with significant intermolecular bonds.

[0052] The isolated algal polysaccharides may be present in the bio-based leather substitute material according to the second aspect of the present invention in any suitable amount. The bio-based leather substitute material may comprise 4 to 50% by weight of isolated algal polysaccharides, for example 4 to 40% by weight of isolated algal polysaccharides.

[0053] The bio-based leather substitute material according to the second aspect of the present invention comprises protein-containing brewer's spent grain or distiller's grain.

[0054] Preferably, the bio-based leather substitute material according to the second aspect of the present invention comprises protein-containing brewer's spent grains.

[0055] The brewer's spent grain or distiller's grain may be present in the bio-based leather substitute material according to the second aspect of the present invention in any suitable amount. The bio-based leather substitute material may comprise 40 to 98% by weight of brewer's spent grain or distiller's grain, for example 50 to 95% by weight of brewer's spent grain or distiller's grain. Preferably, the bio-based leather substitute material comprises 55 to 95% by weight of brewer's spent grain or distiller's grain.

[0056] Brewer's grains or distillers' grains contain proteins. The proteins may be present in the bio-based leather substitute material according to the second aspect of the present invention in any suitable amount. The bio-based leather substitute material may contain 5 to 28% by weight of proteins, for example 6 to 28% by weight of proteins.

[0057] Brewer's grains or distiller's grains typically contain lignin, lipids, and / or cellulose, as described above. Therefore, the bio-based leather substitute according to the second aspect of the present invention may contain 2-30% by mass of lignin. The bio-based leather substitute according to the second aspect of the present invention may contain 1-13% by mass of lipids. The bio-based leather substitute according to the second aspect of the present invention may contain 10-58% by mass of cellulose.

[0058] In the bio-based leather substitute material according to the first or second aspect of the present invention, brewer's spent grain or distiller's spent grain may be replaced with rapeseed meal, a protein-containing grain by-product of rapeseed oil production. Accordingly, when the bio-based leather substitute material according to the first and second aspects of the present invention is referred to herein with respect to other aspects, brewer's spent grain or distiller's spent grain may be replaced with rapeseed meal in those aspects. Rapeseed meal may contain protein, lignin, lipids, and cellulose. Rapeseed meal may contain 15 to 45% protein by weight, e.g., 30 to 36% protein by weight, on a dry weight basis. Rapeseed meal may contain 15 to 50% cellulose by weight, on a dry weight basis. Rapeseed meal may contain 5 to 15% lignin by weight, on a dry weight basis. Rapeseed meal may contain 2 to 22% lipids by weight, on a dry weight basis. As used herein, the "cellulose" of rapeseed meal includes any hemicellulose and starch contained in the rapeseed meal.

[0059] The bio-based leather substitute material according to the first aspect of the present invention comprises the reaction product of a protein extract derived from brewer's spent grains or distiller's spent grains and a cross-linking agent. Multiple cross-linking agents may be used, and preferably two cross-linking agents are utilized, for example, two different cross-linking agents.

[0060] The cross-linking agent can be selected from a cross-linking reagent and / or a cross-linking catalyst. One or more cross-linking reagents and / or cross-linking catalysts may be used. Preferably, a cross-linking reagent and a cross-linking catalyst are used. The cross-linking reagent and the cross-linking catalyst are different.

[0061] When a cross-linking reagent and a cross-linking catalyst are used, they may be used simultaneously or sequentially. Preferably, the bio-based leather substitute material comprises the reaction product of the sequential reaction of a protein extract derived from brewer's spent grains or distiller's grains with a cross-linking reagent and a cross-linking catalyst. For example, the bio-based leather substitute material may comprise the reaction product of the sequential reaction of a protein extract derived from brewer's spent grains or distiller's grains with a cross-linking reagent followed by a cross-linking catalyst, or the reaction product of the sequential reaction of a cross-linking catalyst followed by a cross-linking reagent. Preferably, the bio-based leather substitute material comprises the reaction product of the sequential reaction of a protein extract derived from brewer's spent grains or distiller's grains with a cross-linking reagent followed by a cross-linking catalyst. The leather substitute material comprises a reaction product of a sequential reaction of a protein extract derived from brewer's grains or distiller's grains with a cross-linking agent and then with a cross-linking catalyst. In the context of the present invention, the term "sequential reaction" includes the reaction of a protein extract derived from brewer's grains or distiller's grains with a cross-linking agent, followed by the reaction of the resulting product with the cross-linking catalyst. This term also includes the case where another reaction step, such as a heat treatment or ultrasonic treatment step, is inserted before reacting the protein extract derived from brewer's grains or distiller's grains with the cross-linking agent and the resulting product with the cross-linking catalyst. Preferably, the protein extract derived from brewer's grains or distiller's grains is reacted with the cross-linking agent, and the resulting product is reacted with the cross-linking catalyst.

[0062] Suitable cross-linking reagents include, but are not limited to, citric acid, sebacic acid, formaldehyde, glutaraldehyde, benzaldehyde, oxalic acid, phosphoric acid, glucuronic acid, fumaric acid, benzoic acid, ascorbic acid, tartaric acid, maleic acid, tyrosine, riboflavin, bis(sulfosuccinimidyl) suberate, calcium hydroxide Ca(OH), N-hydroxysulfosuccinimide, urea, genipin, azetidinium, isosorbide, tannic acid, gallic acid, malic acid, ellagic acid, ferulic acid, caffeic acid, vanillin, or combinations thereof.

[0063] Preferably, the cross-linking reagent is a naturally occurring cross-linking agent. As used herein, "naturally occurring" refers to a component obtained or derived from a natural source. Such a component is not derived from petroleum. Such a component is not synthetic.

[0064] Preferably, the cross-linking reagent is selected from citric acid, formaldehyde, urea, genipin, azetidinium, isosorbide, tannic acid, gallic acid, malic acid, ellagic acid, ferulic acid, caffeic acid, or combinations thereof.

[0065] More preferably, the cross-linking agent is selected from citric acid, urea, genipin, isosorbide, tannic acid, gallic acid, malic acid, ellagic acid, ferulic acid, and caffeic acid, or a combination thereof. These cross-linking agents are not only naturally derived but also have good biodegradability and low toxicity. More preferably, the cross-linking agent is selected from citric acid, malic acid, and tannic acid, or a combination thereof. Most preferably, the cross-linking agent is selected from citric acid or malic acid, or a combination thereof.

[0066] The presence of a cross-linking agent in the bio-based leather substitute material according to the first or second aspect of the present invention allows for the formation of a bio-based leather substitute material with increased tensile strength, tear strength and / or abrasion resistance.

[0067] The cross-linking reagent may be present in the bio-based leather substitute material according to the first or second aspect of the present invention in any suitable amount. The bio-based leather substitute material may contain 1-25% by weight of the cross-linking reagent. Preferably, the bio-based leather substitute material contains 5-20% by weight of the cross-linking reagent. It is understood that this amount includes all cross-linking reagent, whether present as cross-linking reagent or cross-linking sites as described below, or otherwise, e.g., excess cross-linking reagent.

[0068] The cross-linking reagent reacts with the protein extract from brewer's spent grains or distiller's spent grains to form a cross-linked protein extract, which is linked via the cross-linking reagent or the cross-linking site of the cross-linking reagent, and it is understood that this depends on the type of cross-link. The cross-linking reagent or its cross-linking site forms part of the structure of the cross-linked protein extract. The cross-linking reagent has a reactive group that interacts with the protein extract. The cross-linking site of the cross-linking reagent is a site that forms part of the cross-linked protein extract structure, and is the moiety that remains in the cross-linked structure after the reaction of the protein extract with the cross-linking reagent and its reactive group interacts with the protein extract. For example, citric acid (cross-linking The chemical formula of the crosslinking reagent is CO2HCH2C(CO2H)(OH)CH2CO2H. Citric acid can crosslink by donating or accepting hydrogen bonds, forming ionic bridges from the conjugate base, or covalently bonding through the reactive groups of the crosslinker as an electrophile or nucleophile. The reactive groups of citric acid can be two CO2H groups, and the crosslinking sites in the structure of the reaction product (crosslinked protein extract) are - O2CCH2C(CO2H)(OH)CH2CO2 - The protein extract may be prepared by converting the COH group (COO - ) may be linked via an O atom of

[0069] Suitable cross-linking catalysts include, but are not limited to, enzymes. When an enzyme is used as a cross-linking catalyst ("enzymatic cross-linking"), the enzyme promotes cross-linking of the protein extract itself. Typically, the protein extracts are linked by bond formation between reactive sites on the protein extracts. A cross-linked protein extract is formed. The cross-linking catalyst functions differently from the cross-linking reagents detailed above in that it does not itself become part of the cross-linked protein extract structure. The enzyme itself is not altered. Exposing the protein extract to the enzyme induces cross-linking of the protein extract, increasing the chain length of the protein extract itself.

[0070] When the cross-linking catalyst is an enzyme, the enzyme can be selected from transglutaminase, lysyl oxidase and laccase, or a combination thereof.

[0071] Preferably, the enzyme is a transglutaminase, more preferably a non-animal derived transglutaminase. Preferably, the transglutaminase is a microbial transglutaminase, e.g., a bacterial transglutaminase. Suitable transglutaminase is available under the trade name Stabizym®, e.g., Stabizym® ​​TGL.

[0072] The cross-linking catalyst catalyzes the formation of bonds between the protein extracts themselves, forming a cross-linked protein extract structure. For example, when transglutaminase is utilized, the cross-linking catalyst catalyzes the formation of isopeptide bonds between carboxyamide and amine groups of the protein extract.

[0073] Thus, the bio-based leather substitute material according to the first aspect of the present invention may comprise a reaction product of a protein extract derived from brewer's spent grains or distiller's spent grains and a cross-linking agent, wherein the reaction product comprises a protein extract cross-linked by isopeptide bonds.

[0074] The cross-linking catalyst may be used in conjunction with a metal salt, such as a calcium salt, e.g., Ca(OH)2, which enhances the effectiveness of the cross-linking catalyst. For example, an enzyme such as transglutaminase may be used in conjunction with a metal salt, such as a calcium salt (e.g., Ca(OH)2).

[0075] The cross-linking catalyst may be present in the bio-based leather substitute material according to the first aspect of the present invention or may be removed during the production of the bio-based leather substitute material, for example by washing, centrifugation or other suitable method, once it has completed its role of catalysing bond formation between the protein extracts.

[0076] When retained in the bio-based leather substitute material according to the first aspect of the present invention, the cross-linking catalyst may be present in the bio-based leather substitute material in any suitable amount. The bio-based leather substitute material according to the first aspect of the present invention may comprise 0.1 to 8% by weight of cross-linking catalyst, for example 1 to 4% by weight of cross-linking catalyst.

[0077] The crosslinking catalyst can be used in an amount of 0.1 to 4% by mass based on the mass % of the protein extract derived from brewer's grains or distiller's lees, i.e., based on the amount of the protein extract derived from brewer's grains or distiller's lees.

[0078] The use of a crosslinking catalyst in forming the bio-based leather substitute material according to the first aspect of the invention can produce a material with increased tear strength, tensile strength, abrasion resistance and / or flexibility, resulting in a bio-based leather substitute material with improved texture and / or hand feel.

[0079] As used herein, the term "crosslinked protein extract" refers to protein extracts linked by the crosslinking reagents described above, as well as protein extracts linked after catalysis by a crosslinking catalyst, e.g., protein extracts linked by isopeptide bonds, or a combination thereof. A crosslinked protein extract can consist of both protein extracts linked by a crosslinking reagent and protein extracts linked after catalysis by a crosslinking catalyst, as further described below.

[0080] The bio-based leather substitute material according to the first aspect of the present invention comprises the reaction product of a protein extract derived from brewer's spent grains or distiller's grains with a cross-linking agent, preferably two cross-linking agents, more preferably a cross-linking reagent and a cross-linking catalyst. The cross-linking reagent and the cross-linking catalyst are distinct. Preferably, the bio-based leather substitute material comprises the reaction product of the sequential reaction of a protein extract derived from brewer's spent grains or distiller's grains with a cross-linking reagent and a cross-linking catalyst. Preferably, the bio-based leather substitute material comprises the reaction product of the sequential reaction of a protein extract derived from brewer's spent grains or distiller's grains with a cross-linking reagent and then a cross-linking catalyst. For example, in such a case, it is understood that the first reaction forms a cross-linked protein extract linked at cross-linking sites. The cross-linked protein extract and other protein extracts are then induced to further cross-link themselves in a second reaction with a cross-linking catalyst. As noted above, the cross-linking sites of the cross-linking groups are present within the cross-linked structure, but the cross-linking catalyst is not present.

[0081] The use of both a crosslinking catalyst and a crosslinking reagent in forming the bio-based leather substitute material according to the first aspect of the present invention can produce a material with increased tensile strength, tear strength, abrasion resistance and / or flexibility, resulting in a bio-based leather substitute material with improved texture and / or hand feel.

[0082] The bio-based leather substitute material according to the first or second aspect of the present invention may further comprise a plasticizer. One or more plasticizers may be present. Preferably, the bio-based leather substitute material according to the first or second aspect of the present invention further comprises a plasticizer.

[0083] Preferably, the plasticizer is of natural origin. Suitable plasticizers include, but are not limited to, glycerol, water, ethylene glycol, polyethylene glycol, propylene glycol, lecithin, sunflower lecithin, mannitol, xylitol, diethylene glycol, tetraethylene glycol, ethanolamine, triethanolamine, acetic acid, glycol, fatliquoring agents, sugar alcohols such as sorbitol, sorbitan, didecyldimethylammonium chloride (DDAC), polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oils, and acetylated monoglycerides.

[0084] Preferably, the plasticizer is selected from glycerol, water, ethanol, acetic acid, fat-reducing agents, sugar alcohols such as sorbitol, sorbitan, polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oils, and acetylated monoglycerides. These plasticizers are not only naturally derived but also have good biodegradability and low toxicity. More preferably, the plasticizer is selected from epoxidized oils, glycerol, and water. Even more preferably, the plasticizer is selected from glycerol and water, or a combination thereof.

[0085] By including a plasticizer in the bio-based leather substitute material according to the first or second aspect of the present invention, it is possible to produce a material with improved flexibility, softness and resilience.

[0086] The plasticizer may be present in the bio-based leather substitute material according to the first or second aspect of the present invention in any suitable amount. The bio-based leather substitute material may contain 1 to 35% by weight of plasticizer, for example 5 to 30% by weight of plasticizer. Preferably, it contains 5 to 25% by weight of plasticizer.

[0087] It will be appreciated that when the bio-based leather substitute material according to the first or second aspect of the present invention is formed by extrusion, as described below, the bio-based leather substitute material preferably comprises a plasticizer.

[0088] The bio-based leather substitute material according to the first or second aspect of the present invention may further comprise one or more additional ingredients. Suitable additional ingredients include antibacterial agents, antifungal agents, inorganic components such as inorganic metal salts such as calcium carbonate (CaCO3), calcium hydroxide (Ca(OH)2), potassium chloride (KCl), etc., binders such as bio-based polymers such as wheat gluten, resins, alginates, chitosan, starch, etc., dyes or colorants, titanium dioxide, calcium carbonate, sodium carbonate, carbon fiber, birch bark powder, nanosilica, olive stone powder, coconut shell powder, cork powder, rice hull char, etc. Examples of suitable additional ingredients include fillers such as char, carboxymethylcellulose, methylcellulose, fibrillated nanocellulose, nanocellulose, gum arabic, agar, chitosan, montmorillonite, talc, calcium silicate, alumina, graphene, kaolin, nanoclay, mica, sodium citrate, wollastonite, rosin, and alignate; pigments or glazes such as titanium dioxide, waxes such as candelilla wax and carnauba wax, and aqueous wax emulsions; oils such as linseed oil, vegetable oil, tea tree oil, coconut oil, almond oil, soybean oil, sunflower oil, bergamot oil, cinnamon oil, olive oil, and rice bran oil; lanolin; benzyl alcohol; salicylic acid; sorbic acid; turmeric; natural gum; or combinations thereof. Preferably, carboxymethylcellulose, methylcellulose, fibrillated nanocellulose, nanocellulose, or combinations thereof are used as one or more additional ingredients. Preferably, carboxymethylcellulose is used as the additional ingredient. The one or more additional ingredients may be present in any suitable amount. Each additional ingredient may be present in the bio-based leather substitute material in an amount of 1 to 50% by weight.

[0089] The bio-based leather substitute material according to the first or second aspect of the present invention does not contain petroleum-derived components. The bio-based leather substitute material according to the first or second aspect of the present invention does not contain petroleum-based components such as petroleum-based resins.

[0090] The bio-based leather substitute material according to the first or second aspect of the present invention is typically provided as a flat piece of material, generally a wide flat piece of material, which can be described as a sheet of flexible material.

[0091] The bio-based leather substitute material according to the first or second aspect of the present invention may have any suitable thickness, preferably 0.2 to 2 mm, or 0.2 to 1.5 mm, for example 0.4 to 1.5 mm, or 0.5 to 1.5 mm, or 0.8 to 1.4 mm.

[0092] The bio-based leather substitute material according to the first or second aspect of the present invention may have any suitable surface area.

[0093] When the bio-based leather substitute material according to the first aspect of the present invention comprises a protein isolate: The bio-based leather substitute material may include a core comprising one or more other components of brewer's spent grains or distiller's draughts. These may be one or more components of brewer's spent grains or distiller's draughts from which a protein extract was isolated during the production of the bio-based leather substitute material according to the first aspect of the present invention, typically the insoluble component(s) of brewer's spent grains or distiller's draughts. Preferably, the core is in the form of a foam having a protein isolate dispersed therein.

[0094] It has been surprisingly and advantageously found that bio-based leather substitute materials according to the first or second aspects of the present invention can mimic the properties of animal-derived leather. The bio-based leather substitute materials exhibit advantageously high tensile strength, tear strength, flexibility, abrasion resistance, and elasticity. The bio-based leather substitute materials also have advantageous texture and "hand."

[0095] The bio-based leather substitute material according to the first or second aspect of the present invention may have a tensile strength of 0.5 to 130 MPa, e.g., 0.5 to 60 MPa, or 2 to 60 MPa, or 3 to 60 MPa, e.g., 4 to 60 MPa, e.g., 4 to 45 MPa, or 4 to 40 MPa, e.g., 7 to 25 MPa. Tensile strength can be measured using a Z3 X500 Universal Testing Machine equipped with an ISO 37 Type 2 dumbbell cutter. Tensile strength is measured in accordance with ISO 3376:2020.

[0096] The tear strength of the bio-based leather substitute material according to the first or second aspect of the present invention can be evaluated by measuring the tear load. The bio-based leather substitute material according to the first or second aspect of the present invention can have a tear load of 4 to 25 N, for example, 5 to 20 N. The tear load is measured in accordance with ISO 3377-1:2011.

[0097] The flexibility of the bio-based leather substitute material according to the first or second aspect of the present invention can be evaluated by measuring its flex resistance. The bio-based leather substitute material according to the first or second aspect of the present invention can have a flex resistance of 15,000 to 300,000 cycles, for example, 20,000 to 200,000 cycles. Flex resistance is measured according to ISO 5402-1:2022.

[0098] The bio-based leather substitute material according to the first or second aspect of the present invention may have an abrasion resistance of 80 to 250 cycles, for example 100 to 200 cycles, as measured in accordance with ISO 17076-1:2020.

[0099] The elasticity of the bio-based leather substitute material according to the first or second aspect of the present invention can be assessed by measuring its elongation under load. The bio-based leather substitute material according to the first or second aspect of the present invention can have an elongation under load of 5-40%, for example 5-30%, or 5-25%, for example 10-25%, or 10-20%. Elongation under load is measured in accordance with ISO 3376:2020. The elongation under load of a material is a measure of the deformation that occurs when the material is subjected to the maximum tensile load that it can withstand.

[0100] The bio-based leather substitute material according to the first or second aspect of the present invention has an advantageous "hand feel." "Hand feel" refers to how a material feels against the skin or in the hand. In the context of the present invention, advantageous hand feel is expressed by the softness of the material and its ability to feel like traditional tanned leather rather than a plastic-based leather substitute.

[0101] In view of these advantageous properties, the non-synthetic bio-based leather substitute materials according to the first and second aspects of the present invention are suitable for use in the fashion industry for products such as bags, shoes, and clothing, as well as in the home industry for upholstery. The bio-based leather substitute material according to the first or second aspect of the present invention can be used to replace animal-derived leather in any product formed therefrom.

[0102] The bio-based leather substitute material according to the first or second aspect of the present invention may be utilized to form constructs as described below.

[0103] The additional material may be attached to or integrated into the bio-based leather substitute material according to the first or second aspect of the present invention. The additional material may be a scaffold support as described below.

[0104] Alternatively, or in addition to the use of additional materials, one or more topcoat layers may be present on the bio-based leather substitute material. The topcoat layer can impart additional advantageous properties, such as water repellency. This topcoat layer may include a coating that can be formed by any suitable method, such as spraying onto the bio-based leather substitute material. The topcoat layer may include components such as bio-based polymers, dyes or colorants, waxes, oils, or combinations thereof. For example, a wax-containing topcoat layer typically improves the hydrophobicity of the bio-based leather substitute material, while dyes or colorants affect its aesthetics. Suitable waxes include, but are not limited to, carnauba wax, sunflower wax, candelilla wax, and beeswax. Suitable bio-based polymers include, but are not limited to, bacterial polylactic acid (PLA), polyethylene terephthalate (PET), polyurethane (PU), and the like. One or more topcoat layers may be present on the bio-based leather substitute material. These layers may be topcoated with the same or different types of topcoats. Preferably, one or two topcoat layers may be present on the bio-based leather substitute material. Preferably, two topcoat layers are present on the bio-based leather substitute material, for example, a topcoat containing a dye or colorant and a topcoat containing a wax applied thereon.

[0105] A construct according to the third or fourth aspect of the invention may comprise two or more layers of bio-based leather substitute material according to the first or second aspect of the invention. Such layers may typically be attached to one another by adhesives, cross-linking agents (e.g., cross-linking agents such as dilute citric acid solution), or stitching. These may be the same bio-based leather substitute material according to the invention, or different bio-based leather substitute materials. For example, a construct may comprise two or more layers of bio-based leather substitute material according to the first aspect of the invention, or a layer of bio-based leather substitute material according to the first aspect of the invention and a layer of bio-based leather substitute material according to the second aspect of the invention.

[0106] The bio-based leather substitute material according to the first or second aspect of the present invention may be treated. For example, the bio-based leather substitute material may be bleached or dyed. Bleaching may be achieved by applying a peroxide source to the bio-based leather substitute material. Suitable peroxide sources include hydrogen peroxide and benzoyl peroxide. The bio-based leather substitute material is then dried. This is typically done to enhance the aesthetic properties of the material. Dyeing may be achieved by applying a dye to the bio-based leather substitute material, typically by painting or immersing the material in a suitable dye solution.

[0107] The bio-based leather substitute material according to the first or second aspect of the present invention may be embossed with a mark, pattern or image. This may be achieved by pressing the bio-based leather substitute material under pressure, or, if the bio-based leather substitute material is formed by solution casting, by solution casting onto a pattern or template or within a marked, patterned or imaged mold. "Clock, pattern or image" includes, but is not limited to, logos, codes, graphics, figures, words, pictures, symbols and text.

[0108] According to a third aspect of the present invention, there is provided a construct comprising two or more layers of bio-based leather substitute material according to the first aspect of the present invention, or a bio-based leather substitute material according to the first aspect of the present invention and a scaffold support.

[0109] According to a fourth aspect of the present invention, there is provided a construct comprising two or more layers of bio-based leather substitute material according to the second aspect of the present invention, or a bio-based leather substitute material according to the second aspect of the present invention and a scaffold support.

[0110] All features of the third and fourth aspects of the invention also apply to all other aspects described herein, as defined below as preferred or optional, and similarly, all features of all other aspects described herein, whether preferred or optional, are also applicable to the third and fourth aspects of the invention.

[0111] The scaffold support may be attached to or integrated with the bio-based leather replacement material. The scaffold support may be attached to the bio-based leather replacement material by adhesive, mechanical pressure, or solvent cast in layers to create a multi-layer construct. If adhesive, the adhesive may be a naturally occurring adhesive or a cross-linking agent (e.g., a cross-linking reagent). The construct may be considered to have a layer of scaffold support attached to a layer of bio-based leather replacement material. It will be understood that multiple layers of scaffold support may be provided. Alternatively, the scaffold support may be integrated into the bio-based leather replacement material to form the construct. The scaffold support may be embedded within the bio-based leather replacement material, or the bio-based leather replacement material may form around the scaffold material, for example, during solvent evaporation, resulting in adhesion / cross-linking between the bio-based leather replacement material and the scaffold support. It will be understood that the construct may include multiple scaffold supports, each attached to or integrated with the bio-based leather replacement material. For example, the construct may be comprised of a bio-based leather substitute material having a scaffold support integrated therein and a scaffold support attached thereto.

[0112] Suitable examples of scaffold supports include, but are not limited to, cotton, viscose, natural cellulosic fibers, perforated mesh, mesh, cheesecloth, linen, or muslin mesh.

[0113] The scaffold support may be formed from one or more other components of the brewer's spent grain or distiller's grain from which the protein extract is separated during the production of the bio-based leather substitute material according to the first aspect of the present invention, typically the insoluble component(s) of the brewer's spent grain or distiller's grain, in addition to other components such as, for example, plasticizers and crosslinkers.

[0114] The scaffold support increases the strength of the construct, particularly its tensile strength and / or tear strength. It will be appreciated that the scaffold support may be provided between layers of bio-based leather substitute material, or on one or both sides of a layer of bio-based leather substitute material, if more than one layer is used.

[0115] As noted above, the constructs according to the third and fourth aspects of the invention may comprise two or more layers of bio-based leather substitute material, which may be the same bio-based leather substitute material according to the invention, or different bio-based leather substitute materials. For example, the construct according to the third aspect of the invention may comprise two or more layers of bio-based leather substitute material according to the first aspect of the invention. The composition may comprise a layer of material and a layer of bio-based leather alternative material according to the second aspect of the present invention.

[0116] Constructs according to the third and fourth aspects of the invention may further comprise one or more topcoat layers, as described above in relation to the topcoat layers of the bio-based leather substitute material, which may impart further advantageous properties such as water repellency.

[0117] According to a fifth aspect of the present invention there is provided an article formed from a bio-based leather substitute material according to the first aspect of the present invention or a construct according to the third aspect of the present invention.

[0118] According to a sixth aspect of the present invention there is provided an article formed from a bio-based leather substitute material according to the second aspect of the present invention or a construct according to the fourth aspect of the present invention.

[0119] All features of the fifth and sixth aspects of the invention are applicable to all other aspects described herein, whether preferred or optional, as described below, and likewise all features of all other aspects described herein, whether preferred or optional, are applicable to the fifth and sixth aspects of the invention.

[0120] Examples of articles according to the fifth and sixth aspects of the present invention include, but are not limited to, bags, shoes, clothing, upholstery, packaging, apparel, saddles, book binders, book covers, luggage tags, jackets, etc. It will be understood that the bio-based leather substitute material can be manufactured to form anything currently made with animal-derived leather.

[0121] The bio-based leather substitute material according to the first aspect of the present invention may be produced by any suitable method.

[0122] According to a seventh aspect of the present invention, there is provided a bio-based leather substitute according to the first aspect of the present invention, the bio-based leather substitute being produced by a method comprising providing a protein extract derived from brewer's spent grains or distiller's spent grains, combining with a cross-linking agent, and forming the bio-based leather substitute.

[0123] According to an eighth aspect of the present invention, there is provided a method of producing a bio-based leather substitute material according to the first aspect of the present invention, the method comprising providing a protein extract derived from brewer's spent grains or distiller's spent grains, combining with a cross-linking agent, and forming the bio-based leather substitute material.

[0124] All features of the seventh and eighth aspects of the invention, whether described below as preferred or optional, are applicable to all other aspects described herein, and likewise all features of all other aspects described herein, whether preferred or optional, are applicable to the seventh and eighth aspects of the invention.

[0125] In the seventh and eighth aspects of the invention, the cross-linking agent is as described herein in relation to the first aspect of the invention. When a cross-linking catalyst is employed, the combination of the protein extract and the cross-linking catalyst is preferably carried out at a temperature below 60°C, for example below 50°C, to prevent denaturation of the cross-linking catalyst.

[0126] Preferably, in the production of a bio-based leather substitute material by the method of the seventh or eighth aspect of the present invention, the protein extract from brewer's or distiller's spent grains is combined with both a cross-linking reagent and a cross-linking catalyst. Preferably, as described above, this is a sequential reaction, carried out in two stages. Preferably, the protein extract is combined with a cross-linking reagent and then a cross-linking catalyst. The protein extract is combined with a cross-linking catalyst. More preferably, the protein extract is combined with a cross-linking agent, and then the resulting product is combined with a cross-linking catalyst. The inventors believe that this two-step cross-linking is advantageous because it results in enhanced tensile strength, tear strength, abrasion resistance and / or flexibility, and improved hand feel.

[0127] The protein extract derived from brewer's spent grain or distiller's spent grain may be kept in solution throughout the method of producing a bio-based leather substitute material according to the seventh or eighth aspect of the present invention.

[0128] In the seventh and eighth aspects of the present invention, following the combination of the protein extract and the crosslinker, a bio-based leather substitute material according to the first aspect of the present invention is formed. The bio-based leather substitute material may be formed by any suitable technique. Suitable techniques include, but are not limited to, casting and optionally rolling, solution casting, thermal extrusion, thermal compression molding or calcination, die casting, pultrusion, electrospraying, wet spinning, dry spinning, melt spinning, and gel spinning, with casting, solution casting, thermal extrusion, thermal compression molding, or calcination being preferred. The bio-based leather substitute material may be further dried. Suitable drying conditions include microwave drying, radio frequency drying, vacuum drying, and freeze drying. The bio-based leather substitute material may also be further pressed to achieve the required thickness.

[0129] Preferably, the bio-based leather substitute material according to the seventh or eighth aspect of the present invention is formed by solution casting.

[0130] Solution casting is preferably carried out in a mold, such as a silicone mold. The mold may be imparted with a mark, pattern, image, or shape to form a mark, pattern, or image in the resulting bio-based leather substitute material. Any suitable temperature can be used in solution casting. The temperature can be ambient or higher, for example, up to 60°C. Preferably, the mold is at the same temperature as the solution introduced therein.

[0131] After formation, such as by solution casting, the bio-based leather substitute material may be dried by any suitable method. Suitable drying conditions include microwave drying, radio frequency drying, vacuum drying, and freeze drying.

[0132] Prior to the formation of the bio-based leather substitute material, the methods according to the seventh and eighth aspects of the invention may include a heat treatment step and / or an ultrasonic treatment step. Preferably, the methods according to the seventh and eighth aspects of the invention include a heat treatment step and an ultrasonic treatment step.

[0133] Preferably, the methods according to the seventh and eighth aspects of the present invention include a heat treatment and / or ultrasonic treatment step prior to the formation of the bio-based leather substitute material. Preferably, the heat treatment and / or ultrasonic treatment is performed after protein extraction from brewer's spent grains or distiller's grains (described below) and prior to the formation of the bio-based leather substitute material. Preferably, the heat treatment and / or ultrasonic treatment step is performed after combining the protein extract from brewer's spent grains or distiller's grains with a cross-linking agent. When two or more cross-linking agents, such as two or more cross-linking reagents and / or cross-linking catalysts, are used, preferably the cross-linking reagents and cross-linking catalysts described above, the heat treatment and / or ultrasonic treatment step is performed between reaction steps using different cross-linking agents, such as between the addition of the cross-linking reagent and the addition of the cross-linking catalyst, or before or after both additions, preferably between or after the addition of both reaction steps using different cross-linking agents.

[0134] This heat treatment process may involve heating, pasteurization, curing and / or thermal annealing. Without being bound by theory, the inventors believe that this heat treatment step promotes the formation of protein nanofibrils (changing the protein structure), dissolving the components, dispersing the components, and / or promoting cross-linking of the bio-based leather substitute material after the addition of a cross-linking agent. The inventors believe that the heat treatment step leads to an improvement in the tensile strength of the formed bio-based leather substitute material.

[0135] The heat treatment step involves heating to 50°C to 100°C, for example, 60°C to 90°C, or 70°C to 90°C. The heat treatment step may be carried out for any appropriate time, such as 15 minutes to 4 hours, or 30 minutes to 3 hours. Stirring may be carried out during the heat treatment.

[0136] When the method according to the seventh and eighth aspects of the present invention includes a heat treatment step and an ultrasonic treatment step, the ultrasonic treatment may be carried out simultaneously with the heat treatment, or before or after the heat treatment. Preferably, the ultrasonic treatment is carried out subsequent to the heat treatment step, i.e., after the heat treatment step. This is typically carried out immediately after the heat treatment step.

[0137] Ultrasonication treatment involves sonication and the application of ultrasonic frequencies. This may be accomplished using an ultrasonic processor. A suitable ultrasonic processor is the Fischerbrand® Sonic Dismembrator. The applied power for ultrasonic treatment may be 15 to 700 watts, e.g., 50 watts, 120 watts, 500 watts, or 700 watts, and preferably 15 to 500 watts, e.g., 15 to 120 watts. The applied frequency may be 20 kHz. Ultrasonic treatment may be performed in pulses, such as 5 to 30 second pulses. Ultrasonic treatment may be performed for 1 to 20 minutes, e.g., 1 to 15 minutes, e.g., 1 to 10 minutes, or 1 to 5 minutes. Without being bound by theory, the inventors believe that this ultrasonic treatment step promotes the formation of protein nanofibrils (changing the protein structure), dissolving components, dispersing components, and / or promoting crosslinking of the bio-based leather substitute material after the addition of a crosslinking agent. The inventors believe that the ultrasonic treatment process leads to improved tensile strength of the formed bio-based leather substitute material.

[0138] In the seventh and eighth aspects of the present invention, the method may further comprise obtaining a protein extract from brewer's grains or distiller's lees. Preferably, in the seventh and eighth aspects of the present invention, the method further comprises obtaining a protein extract from brewer's grains or distiller's lees. The protein extract from brewer's grains or distiller's lees is obtained by solubilizing proteins in brewer's grains or distiller's lees. The protein extract from brewer's grains or distiller's lees can be obtained by alkaline extraction, ethanol extraction, organic solvent extraction, acid extraction, salt solution extraction, hot water extraction, enzyme extraction, or sonication (ultrasound-assisted extraction). Preferably, the extraction is performed in solution. Preferably, the protein extract is obtained by alkaline extraction. An aqueous alkaline solution may be used for alkaline extraction. Suitable alkaline reagents for alkaline extraction include, but are not limited to, aqueous solutions of NaOH, KOH, or Ca(OH), preferably 0.05 M to 1 M, e.g., 0.1 M. The aqueous solution of the alkaline reagent used in alkaline extraction is an aqueous alkaline solution. The temperature at which alkaline extraction is carried out is 50°C to 75°C, preferably 50°C to 70°C, or 55°C to 70°C. The alkaline extraction is carried out for 20 minutes to 300 minutes, preferably 20 minutes to 100 minutes, for example, 20 minutes to 80 minutes.

[0139] Preferably, the protein extract remains in solution after extraction. After obtaining the protein extract from brewer's spent grains or distiller's grains, the solubilized protein extract is kept in the same solution as one or more other components of the brewer's spent grains or distiller's grains from which the proteins were extracted, and the solubilized protein extract remains in solution. The liquor may be used to produce a bio-based leather substitute. In such cases, the bio-based leather substitute would therefore include other components of the brewer's spent grain or distiller's grain. These one or more other components may include insoluble component(s) of the brewer's spent grain or distiller's spent grain, such as grain husks.

[0140] When the protein extract is a protein isolate, after obtaining the protein extract from brewer's spent grains or distiller's grains, the solubilized protein extract is separated and optionally purified from one or more other components of the brewer's spent grains or distiller's grains, typically the insoluble component(s) of the brewer's spent grains or distiller's grains. The separated brewer's spent grains or distiller's grains components, typically the insoluble component(s) of the brewer's spent grains or distiller's grains, may be later recombined during the production of the bio-based leather substitute material. In some cases, these components are utilized to form a core through which the protein isolate permeates and disperses. Alternatively, after separation, one or more other components, typically the insoluble component(s), may not be recombined. In this case, after separation, the one or more other components may be utilized to form a scaffold support that is attached to or integrated into the bio-based leather substitute material to form a construct, as described above. On the other hand, after separation, one or more other components, typically the insoluble component(s), may be discarded and not further utilized in the manufacture of bio-based leather substitute materials or constructs or articles comprising such.

[0141] Therefore, in the seventh and eighth aspects of the present invention, when the protein extract is a protein isolate, the method may further include obtaining a protein extract from brewer's grains or distiller's grains, separating the protein extract from one or more other components of the brewer's grains or distiller's grains, typically the insoluble component(s) of the brewer's grains or distiller's grains, and optionally purifying the protein extract to form a protein isolate. The protein extract can be obtained by solubilizing the proteins in the brewer's grains or distiller's grains as described above. The protein extract can then be separated to obtain a protein isolate by filtration, e.g., filtering the insoluble component(s) of the brewer's grains or distiller's grains from the solution, and / or by centrifugation, e.g., centrifugation to separate the insoluble component(s) of the brewer's grains or distiller's grains. Preferably, the separation is carried out by filtration and / or centrifugation, more preferably by filtration. Suitable purification techniques for protein isolates include precipitation and / or centrifugation or filtration. One or more other components of the brewer's or distiller's grains from which the protein isolate is separated are typically insoluble in the solution used for protein extraction.

[0142] Purification of the protein isolate from brewer's or distiller's grains may involve precipitation, for example, cold precipitation or acid precipitation, preferably acid precipitation.

[0143] For cold precipitation, the solution can be maintained at a temperature of 0-4°C. The solution may be maintained at this temperature for 12 to 48 hours, allowing the protein to precipitate from the solution.

[0144] In the case of acid precipitation, an acid reagent may be added to the solution. The acid reagent may be selected from any suitable acid, such as hydrochloric acid, citric acid, or acetic acid. In the case of acid precipitation, the acid reagent is added in an amount suitable to provide a pH of 1 to 6, preferably 3, 4, or 5. The amount of acid reagent added may vary accordingly. Acid precipitation is preferably used when the protein is extracted using an alkaline solution.

[0145] Purification of the protein isolate from brewer's or distiller's grains may alternatively or additionally involve centrifugation or filtration. Preferably, this is carried out at ambient temperature or at a temperature of 0-20°C, for example 0-10°C. In the case of centrifugation, this takes from 10 minutes to 1 hour, for example 30 minutes. Centrifugation is carried out at 2000-9000 x g, preferably 3000 x g. .

[0146] Preferably, the brewer's spent grain or distiller's grain-derived protein extract or protein isolate remains in solution. The protein extract can remain in solution during combination with a crosslinking agent in the manufacturing process of the bio-based leather substitute. When the protein isolate is purified as described above, it is redissolved in an aqueous solution, typically at a pH of 4 to 10, e.g., 6 to 8. The aqueous solution is preferably water, or an aqueous solution of water and an acid, e.g., hydrochloric acid, or water and an alkali salt, e.g., sodium hydroxide.

[0147] Preferably, in the seventh and eighth aspects of the present invention, the method further comprises the steps of obtaining a protein extract from brewer's spent grains or distiller's grains, separating the protein extract from one or more other components of the brewer's spent grains, typically the insoluble component(s) of the brewer's spent grains or distiller's grains, preferably by filtration and / or centrifugation, more preferably by filtration, to obtain a protein isolate, and optionally purifying the protein isolate. Preferred purification methods are as described above.

[0148] The brewer's grain or distiller's grain from which the protein extract is obtained can be in wet or dry form. Preferably, the brewer's grain or distiller's grain is dried brewer's grain or distiller's grain. Thus, the seventh and eighth aspects of the present invention can include an additional step of drying the brewer's grain or distiller's grain before obtaining the protein extract derived from the brewer's grain or distiller's grain. By "dry form" is meant brewer's grain or distiller's grain having a moisture content of less than 20% by weight, preferably less than 15% by weight. It will be understood that brewer's grain or distiller's grain is usually obtained in wet form from breweries or other sources.

[0149] When brewer's grains or distillers' lees are used in a dried form, they may be shredded or ground before extracting proteins therefrom. Thus, in the seventh and eighth aspects of the present invention, the method may comprise a step of shredding or grinding the brewer's grains or distillers' lees before obtaining a protein extract from the brewer's grains or distillers' lees. Preferably, the brewer's grains or distillers' lees are ground before extracting proteins. When the brewer's grains or distillers' lees are ground, they are preferably ground to a particle size of 10 to 600 μm, e.g., 30 to 600 μm. This can be achieved by using a high-speed multi-foam grinder and sieving to the desired particle size. Grinding the brewer's grains or distillers' lees advantageously smooths the texture of the resulting bio-based leather substitute material.

[0150] The brewer's spent grains or distiller's grains may be washed with water, preferably distilled water, before use. This washing may be performed on either wet or dry brewer's spent grains or distiller's grains, preferably dry. The seventh and eighth aspects of the present invention may include a step of washing the brewer's spent grains or distiller's grains. This step is performed before extracting proteins.

[0151] When the bio-based leather substitute material according to the first aspect of the present invention further comprises an isolated algal polysaccharide or a salt thereof, in the seventh and eighth aspects of the present invention, the method may further comprise a step of heat-treating the isolated algal polysaccharide or a salt thereof. Preferably, the heat treatment is carried out in water or distilled water. Heat-treating the isolated algal polysaccharide or a salt thereof may comprise heating the isolated algal polysaccharide or a salt thereof in a solution, preferably an aqueous solution, more preferably in water or distilled water, to a temperature of 80°C or above, for example 80°C to 100°C, preferably 85°C to 100°C, more preferably 85°C to 95°C. Without being bound by theory, the inventors believe that the isolated algal polysaccharides dissolve upon heating, thereby breaking down their network and allowing them to be separated. Upon cooling, the isolated algal polysaccharides release the important components. They can arrange into tightly packed chains with intramolecular bonds, forming a bonding network to the other components of the bio-based leather substitute. The heat treatment may be carried out for between 5 and 120 minutes.

[0152] When the bio-based leather substitute according to the first aspect of the present invention further comprises isolated algal polysaccharides or salts thereof, the step of obtaining a protein extract from brewer's spent grains or distiller's spent grains may be carried out separately from the heat treatment of the isolated algal polysaccharides. The resulting solutions may then be combined in the method for producing a bio-based leather substitute, and other necessary ingredients may be added. Alternatively, the heat treatment of the isolated algal polysaccharides and the step of obtaining a protein extract from brewer's spent grains or distiller's spent grains may be carried out together in the same solution. In this case, it is understood that the temperature at which the heat treatment and extraction are carried out is 80°C to 95°C, or 85°C to 95°C. The solution may also be an aqueous solution of an alkaline reagent, as described above.

[0153] In the seventh and eighth aspects of the present invention, after providing (extracting) the protein extract derived from brewer's spent grains or distiller's draughts, the method for producing a bio-based leather substitute may further include a neutralization step. Preferably, if present, the neutralization step is performed after providing (extracting) the protein extract derived from brewer's spent grains or distiller's draughts and before forming the bio-based leather substitute. Preferably, if present, the neutralization step is performed before combining the protein extract derived from brewer's spent grains or distiller's draughts with the crosslinker. The inventors believe that such a neutralization step is intended to prevent unwanted oxidation / hydrolysis and damage of the protein extract, particularly when protein extraction is achieved by alkaline extraction. Neutralization is achieved by lowering the pH of the solution containing the protein extract derived from brewer's spent grains or distiller's draughts to a neutral pH, for example, pH 6 to 8, preferably pH 7. Neutralization is achieved by adding a neutralizing agent. When extraction is achieved by alkaline extraction, suitable neutralizing agents include acids. Any acid can be used. For example, suitable acids include citric acid, malic acid, hydrochloric acid, nitric acid, sulfuric acid, etc. The amount of acid added is the amount needed to reach the desired pH.

[0154] When a cross-linking reagent is utilized in the method for producing a bio-based leather substitute, in addition to functioning as a cross-linking reagent as described herein, the cross-linking reagent may also act as a neutralizing agent. Thus, neutralization may be achieved by combining a protein extract with the cross-linking reagent. Suitable cross-linking reagents that may also act as neutralizing agents include, but are not limited to, citric acid, malic acid, tannic acid, gallic acid, ellagic acid, ferulic acid, and caffeic acid. However, this is not necessarily the case. It is understood that the methods according to the seventh and eighth aspects of the present invention may include a neutralization step utilizing an acid other than an acid suitable to act as a cross-linking reagent, such as hydrochloric acid, after which the cross-linking reagent can be used as a cross-linking agent in the production of a bio-based leather substitute according to the present invention.

[0155] Preferably, when a cross-linking catalyst is used as the cross-linking agent, neutralization is carried out prior to reaction with the cross-linking catalyst. If a cross-linking reagent is also used in the preceding reaction step, neutralization may be carried out prior to reaction with the cross-linking reagent, or a neutralization step may be carried out with the cross-linking reagent acting as a neutralizing agent as described above. If the cross-linking reagent is also combined with the protein extract derived from brewer's spent grains or distiller's grains in the same reaction step, i.e., introduced simultaneously, neutralization may be carried out prior to reaction with the cross-linking reagent and cross-linking catalyst.

[0156] After neutralization, the resulting solution containing the protein extract from brewer's spent grains or distiller's grains may be centrifuged. The recovered protein may be redissolved in an aqueous solution, typically having a pH of 4 to 10, e.g., a pH of 6 to 8. The aqueous solution is preferably water, or an aqueous solution of water and an acid, e.g., hydrochloric acid, or an aqueous solution of water and an alkali salt, e.g., aqueous sodium hydroxide.

[0157] In the seventh and eighth aspects of the present invention, when the cross-linking agent is a cross-linking reagent and no cross-linking catalyst is used, instead of neutralization, the method according to the seventh or eighth aspect of the present invention may further comprise acidification after the extraction and optional isolation of proteins from brewer's or distiller's grains. Acidification reduces the pH of the solution containing the protein extract from brewer's or distiller's grains to an acidic pH, e.g., less than 6, preferably to a pH of 2 to 4. Acidification may be achieved by adding an acid, e.g., an acid selected from nitric acid, hydrochloric acid, citric acid, and sulfuric acid. Preferably, the acid is introduced in an amount that reduces the pH of the solution to less than 6, e.g., 2 to 4.

[0158] For the acidification, the cross-linking reagent can also act as the acid detailed above for the acidification. Thus, acidification can be achieved by combining a protein extract derived from brewer's grains or distiller's grains with a cross-linking reagent.

[0159] In the seventh and eighth aspects of the present invention, once the protein extract has been combined with the crosslinker and, optionally, the plasticizer and / or one or more additional ingredients, excess crosslinker (either the crosslinking reagent and / or the crosslinking catalyst), plasticizer, one or more additional ingredients, and / or other non-protein components can be removed. This can be accomplished by filtration and / or centrifugation, preferably by centrifugation. The resulting product can be redissolved in an aqueous solution, typically pH 4-10, e.g., pH 6-8, or can be used in the resulting form to form the bio-based leather substitute material. The aqueous solution can be water, or an aqueous solution of water and an acid, e.g., hydrochloric acid, or an aqueous solution of water and an alkali salt, e.g., aqueous sodium hydroxide.

[0160] In the seventh and eighth aspects of the present invention, the plasticizer and / or one or more additional components can be introduced at any time after obtaining the protein extract from brewer's spent grains or distiller's spent grains and before forming the bio-based leather substitute material. In particular, the plasticizer and / or one or more additional components can be introduced before, during, and / or after combining the protein extract with the cross-linking agent. The plasticizer and / or one or more additional components can be introduced before, during, and / or after the heat treatment and / or ultrasonic treatment step. Preferably, the introduction is before the heat treatment and / or ultrasonic treatment step, more preferably after combining with the cross-linking agent. When multiple cross-linking agents are used, such as two or more cross-linking reagents and / or cross-linking catalysts, preferably the cross-linking reagents and cross-linking catalysts described above, the plasticizer and / or one or more additional components can be introduced between different cross-linking agent reaction steps, for example, between the addition of the cross-linking reagent and the cross-linking catalyst, or before or after both additions. Different components may be introduced at different stages. For example, the introduction of a plasticizer may occur after combining the protein extract with the cross-linking agent, while the introduction of one or more additional ingredients, such as a filler, may occur during combination of the protein extract with the cross-linking agent. Preferably, the plasticizer is introduced after combining the protein extract with the cross-linking agent, i.e., into the cross-linked protein extract.

[0161] When multiple cross-linking agents are used, in addition to the above, a plasticizer and / or one or more additional components may be introduced during the combination of the protein extract with any of the multiple cross-linking agents, or between reaction steps using different cross-linking agents. For example, when both a cross-linking reagent and a cross-linking catalyst are used, in addition to the above, a plasticizer and / or one or more additional components may be introduced during or between the reaction of the protein extract with the cross-linking reagent and / or cross-linking catalyst, and before or after the combination of the cross-linking reagent and cross-linking catalyst (cross-linking agent) as described above.

[0162] In the seventh and eighth aspects of the present invention, preferred methods for producing bio-based leather substitute materials include: The method comprises steps (1) to (3) as detailed below. All preferred or optional features detailed above for the seventh and eighth aspects of the invention apply to the relevant steps. (1) obtaining a protein extract from brewer's grain or distiller's grain, preferably obtaining a protein isolate from brewer's grain or distiller's grain; (2) combining the protein extract with a cross-linking agent to form a reaction product of the brewer's spent grain or distiller's spent grain-derived protein extract and the cross-linking agent; and (3) Forming the bio-based leather substitute material, preferably by solution casting.

[0163] For step (1) of the preferred method, extraction is preferably carried out in solution. Preferably, the protein extract is extracted by alkaline extraction, such as using an aqueous alkaline solution. Preferably, after extraction, the protein extract is separated from one or more other components of the brewer's spent grains or distiller's grains, preferably the insoluble component(s) of the brewer's spent grains or distiller's grains, by filtration and / or centrifugation to form a protein isolate, which is optionally purified.

[0164] For step (2) of the preferred method, the protein extract, preferably derived from brewer's grains or distiller's spent grains, is combined with a cross-linking reagent and / or a cross-linking catalyst. Preferably, the protein extract is combined with a cross-linking reagent and a cross-linking catalyst. Preferably, the protein extract is combined with a cross-linking reagent and a cross-linking catalyst in a sequential reaction. Preferably, the protein extract, derived from brewer's grains or distiller's spent grains, is reacted sequentially with a cross-linking reagent and then with a cross-linking catalyst. Preferably, the protein extract, derived from brewer's grains or distiller's spent grains, is reacted with a cross-linking reagent, and the resulting product is reacted with a cross-linking catalyst.

[0165] Optionally, after step (1) and before step (2), the protein extract derived from brewer's spent grains or distiller's grains may be subjected to a neutralization step. Preferably, the cross-linking reagent acts as the neutralizing agent.

[0166] Preferably, between steps (2) and (3), the product obtained from the combination of the protein extract derived from brewer's spent grains or distiller's spent grains and the cross-linking agent is subjected to heat treatment and / or ultrasonic treatment, preferably both. When a cross-linking reagent and a cross-linking catalyst are used as the cross-linking agents described herein, the heat treatment and / or ultrasonic treatment step may be performed between the addition of the cross-linking reagent and the addition of the cross-linking catalyst, or before or after the addition of both, preferably between the addition of different cross-linking agents or after the addition of both. Preferably, the heat treatment includes heating to a temperature of 50 to 100°C, for example, 70 to 90°C.

[0167] For step (3), preferably, the formation of the bio-based leather substitute material is achieved by solution casting.

[0168] In the preferred method, the plasticizer and / or one or more additional ingredients may preferably be added following step (1) before step (2), during step (2), and / or after step (2) but before step (3).

[0169] In a preferred method, preferably brewer's spent grains are used. Preferably, the brewer's or distiller's grains from which the protein extract is obtained are in a dried form in the preferred method.

[0170] According to a ninth aspect of the present invention, there is provided a bio-based leather substitute material according to the second aspect of the present invention; wherein the bio-based leather substitute material comprises an isolated algal polysaccharide or a salt thereof. and combining it with protein-containing brewer's or distiller's grains and a cross-linking agent to form a bio-based leather substitute material.

[0171] According to a tenth aspect of the present invention, there is provided a method of producing a bio-based leather substitute material according to the second aspect of the present invention, the method comprising the steps of subjecting isolated algal polysaccharides or salts thereof to a heat treatment; combining with protein-containing brewer's spent grains or distillers' grains and a cross-linking agent; and forming the bio-based leather substitute material.

[0172] All features of all other aspects described herein, whether preferred or optional, are applicable to the ninth and tenth aspects of the invention. Similarly, all features of all other aspects described herein, whether preferred or optional, are applicable to the ninth and tenth aspects of the invention.

[0173] For the ninth and tenth aspects of the invention, following combination of the protein extract and crosslinker, the bio-based leather substitute material according to the first aspect of the invention may be formed by any suitable technique. Suitable techniques include, but are not limited to, casting, solution casting, thermal extrusion, thermal compression molding or calcination, die casting, pultrusion, electrospraying, wet spinning, dry spinning, melt spinning, and gel spinning, with casting, solution casting, thermal extrusion, thermal compression molding, or calcination being preferred. The bio-based leather substitute material may be further subjected to drying. The bio-based leather substitute material may also be further subjected to pressing to achieve the desired thickness.

[0174] The brewer's spent grains or distillers' grains used in the ninth and tenth aspects of the present invention can be used in dry or wet form. Preferably, the brewer's spent grains or distillers' grains are dried brewer's spent grains or dried distillers' grains. Therefore, the ninth and tenth aspects of the present invention may include an additional step of drying the brewer's spent grains or distillers' grains before use.

[0175] When brewer's grains or distillers' lees are used in a dried form, they may be shredded or ground before use. Accordingly, in the ninth and tenth aspects of the present invention, the method may include a step of shredding or grinding the brewer's grains or distillers' lees. Preferably, the brewer's grains or distillers' lees are ground. When brewer's grains or distillers' lees are ground, they are preferably ground to a particle size of 10 to 600 μm, e.g., 30 to 600 μm. This can be achieved using a high-speed multi-form grinder and sieving to the desired particle size. Grinding the brewer's grains or distillers' lees advantageously smooths the texture of the resulting bio-based leather substitute material.

[0176] For the ninth and tenth aspects of the present invention, the method includes heat-treating the isolated algal polysaccharide or salt thereof. Preferably, the heat-treating is carried out in water or distilled water. Heat-treating the isolated algal polysaccharide or salt thereof can include heating the isolated algal polysaccharide or salt thereof in a solution, preferably an aqueous solution, more preferably water or distilled water, to 80°C or higher, e.g., 80°C to 100°C, preferably 85°C to 100°C, more preferably 85°C to 95°C. Without being bound by theory, the inventors believe that the isolated algal polysaccharide dissolves upon heating, decomposing its network and allowing it to be separated. Upon cooling, the isolated algal polysaccharide arranges into tightly packed chains with significant intramolecular bonds, which can form a binding network to other components of the bio-based leather substitute material. The heat-treating may be carried out for a period of 5 to 120 minutes.

[0177] In the ninth and tenth aspects of the present invention, other optional ingredients, such as plasticizers, utilized in producing the bio-based leather substitute material according to the second aspect may be crosslinking agents and brewers. It is understood that it may be introduced simultaneously with the draff or distiller's grains, or may be introduced as part of a solution of isolated algal polysaccharides that is subjected to heat treatment.

[0178] According to an eleventh aspect of the present invention, there is provided the use of brewer's spent grain or distiller's spent grain in the manufacture of a bio-based leather substitute material according to the first aspect of the present invention.

[0179] According to a twelfth aspect of the present invention, there is provided the use of brewer's spent grain or distiller's spent grain in the manufacture of a bio-based leather substitute material according to the second aspect of the present invention.

[0180] All features of all other aspects described herein, whether preferred or optional, are applicable to the eleventh and twelfth aspects of the invention. Similarly, all features of all other aspects described herein, whether preferred or optional, are applicable to the eleventh and twelfth aspects of the invention.

[0181] According to a thirteenth aspect of the present invention, there is provided a bio-based leather substitute material comprising a protein extract derived from brewer's spent grains or distiller's spent grains and a plasticizer.

[0182] According to a fourteenth aspect of the present invention, there is provided a construct comprising two or more layers of the bio-based leather substitute material according to the thirteenth aspect of the present invention, or the bio-based leather substitute material according to the thirteenth aspect of the present invention and a scaffold support.

[0183] According to a fifteenth aspect of the present invention, there is provided an article formed from: a bio-based leather substitute material according to the thirteenth aspect of the present invention; or a construct according to the fourteenth aspect of the present invention.

[0184] According to a sixteenth aspect of the present invention, there is provided a bio-based leather substitute material according to the thirteenth aspect of the present invention; wherein the bio-based leather substitute material is produced by a method comprising providing a protein extract derived from brewer's spent grains or distiller's spent grains and combining it with a plasticizer to form the bio-based leather substitute material.

[0185] According to a seventeenth aspect of the present invention, there is provided a method of producing a bio-based leather substitute material according to the thirteenth aspect of the present invention, the method comprising providing a protein extract derived from brewer's spent grains or distiller's spent grains and combining it with a plasticizer to form the bio-based leather substitute material.

[0186] According to an eighteenth aspect of the present invention, there is provided the use of brewer's spent grain or distiller's spent grain in the manufacture of a bio-based leather substitute material according to the thirteenth aspect of the present invention.

[0187] All features of all other aspects described herein, whether preferred or optional, are applicable to aspects 13 to 18 of the invention. Similarly, all features of all other aspects described herein, whether preferred or optional, are applicable to aspects 13 to 18 of the invention.

[0188] In the bio-based leather substitute material according to the thirteenth aspect of the present invention, the protein extract derived from brewer's spent grains or distiller's spent grains and the plasticizer may be as described above for the bio-based leather substitute material according to the first aspect of the present invention.

[0189] Preferably, in the case of the bio-based leather substitute material according to the thirteenth aspect of the present invention, the plasticizer is selected from the group consisting of glycerol, ethylene glycol, polyethylene glycol, propylene glycol, lecithin, sunflower lecithin, mannitol, xylitol, diethylene glycol, tetraethylene glycol, ethanolamine, triethanolamine, acetic acid, glycol The additives may be selected from the group consisting of ethanol, fat-liquor, sugar alcohols such as sorbitol, sorbitan, didecyldimethylammonium chloride (DDAC), polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oils, and acetylated monoglycerides.

[0190] Preferably, the plasticizer is a polyol-based plasticizer. Suitable polyol-based plasticizers include glycerol, ethylene glycol, polyethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, sugar alcohols such as sorbitol, sorbitan, and erythritol.

[0191] More preferably, the plasticizer is selected from glycerol, acetic acid, fatliquors, sorbitol, sorbitan, polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oils and acetylated monoglycerides. Most preferably, the plasticizer is glycerol.

[0192] In the case of a method according to the fifteenth or sixteenth aspect of the present invention, the method for providing a brewer's spent or distiller's grain derived protein extract, preferably a brewer's spent or distiller's grain derived protein isolate, is as described above in relation to the seventh and eighth aspects of the present invention. Furthermore, in the case of a method according to the fifteenth or sixteenth aspect of the present invention, the method for forming a bio-based leather substitute material is as described above in relation to the seventh and eighth aspects of the present invention.

[0193] Preferably, in the case of the method according to the fifteenth or sixteenth aspect of the present invention, the method comprises neutralizing the protein extract derived from brewer's spent grains or distillers' lees following the provision (extraction). Preferably, in the case of the method according to the fifteenth or sixteenth aspect of the present invention, the neutralization step is carried out following the provision (extraction) of the protein extract derived from brewer's spent grains or distillers' lees and prior to the formation of the bio-based leather substitute material. Preferably, in the case of the method according to the fifteenth or sixteenth aspect of the present invention, the neutralization step is carried out prior to combining the protein extract derived from brewer's spent grains or distillers' lees with the plasticizer. The neutralization step is as described above with respect to the methods according to the seventh and eighth aspects of the present invention. The inventors believe that such neutralization prevents undue oxidation / hydrolysis and damage to the protein extract, particularly when protein extraction is achieved by alkaline extraction. Neutralization involves lowering the pH of the solution containing the protein extract derived from brewer's spent grains or distillers' lees to a neutral pH, for example, a pH of 6 to 8, preferably 7. Neutralization can be achieved by adding a neutralizing agent. When extraction is achieved by alkaline extraction, suitable neutralizing agents include acids. Any acid can be used. For example, suitable acids include citric acid, malic acid, hydrochloric acid, nitric acid, and sulfuric acid. The amount of acid added is the amount necessary to reach the desired pH.

[0194] Preferably, in the case of the method according to the fifteenth or sixteenth aspect of the present invention, the method further comprises a heat treatment and / or ultrasonic treatment step prior to the formation of the bio-based leather substitute material. More preferably, the method according to the fifteenth or sixteenth aspect of the present invention further comprises a heat treatment and ultrasonic treatment step. The heat treatment and / or ultrasonic treatment may be carried out after the extraction of proteins from the brewer's spent grains or distiller's lees and prior to the formation of the bio-based leather substitute material. The heat treatment and / or ultrasonic treatment may be carried out before or after, preferably after, combining the protein extract derived from the brewer's spent grains or distiller's lees with the plasticizer. The heat treatment and / or ultrasonic treatment step is as described above for the methods according to the seventh and eighth aspects of the present invention.

[0195] The heat treatment step may involve heating to a temperature of 50 to 100°C, for example 60 to 90°C, or 70 to 90°C.

[0196] When the method according to the fifteenth or sixteenth aspect of the present invention includes the steps of heat treatment and ultrasonic treatment, the ultrasonic treatment may be carried out simultaneously with the heat treatment, or may be carried out before or after the heat treatment. Preferably, the ultrasonic treatment is carried out subsequent to, i.e., after, the heat treatment step, which is typically immediately after the heat treatment step.

[0197] Ultrasonic treatment includes sonication and application of ultrasonic frequencies. An ultrasonic treatment device may be used. Suitable ultrasonic treatment devices include the Sonic Dismembrator manufactured by Fischerbrand®. For ultrasonic treatment, the applied power may be 15 to 700 watts, e.g., 50 watts, 120 watts, 500 watts, or 700 watts, and preferably 15 to 500 watts, e.g., 15 to 120 watts. The applied frequency may be 20 kHz. Ultrasonic treatment may be performed in pulses, such as 5 to 30 second pulses. Ultrasonic treatment may be performed for 1 to 20 minutes, e.g., 1 to 15 minutes, 1 to 10 minutes, or 1 to 5 minutes.

[0198] Without being bound by theory, the inventors believe that the inclusion of a heat treatment and / or ultrasonic treatment step for the method according to the fifteenth or sixteenth aspect alters the structure of the protein, promoting the formation of protein nanofibrils that combine to form the bio-based leather substitute material according to the thirteenth aspect of the invention, thereby avoiding the need for a cross-linking agent.

[0199] Therefore, preferably, the bio-based leather substitute material according to the eleventh aspect of the present invention does not further comprise a crosslinking agent.

[0200] Preferably, the methods according to the fifteenth and sixteenth aspects of the present invention comprise the following steps: (1) obtaining a protein extract derived from brewer's grain or distiller's grain, preferably obtaining a protein isolate derived from brewer's grain or distiller's grain; (2) combining the protein extract with a plasticizer to form a reaction product of the protein extract derived from brewer's grains or distiller's grains and the plasticizer; (3) preferably subjecting the resulting product to a heat treatment and / or ultrasonic treatment step; and (4) Forming the bio-based leather substitute material, preferably by solution casting.

[0201] All features described herein may be combined with any of the above aspects in any combination.

[0202] All references herein to compounds are intended to include the compound per se and, where appropriate, derivatives, hydrates, solvates, complexes, isomers and tautomers thereof.

[0203] For a better understanding of the present invention and to show how embodiments thereof may be put into practice, reference is now made to the following examples, by way of illustration.

[0204] As used herein, the term "ambient temperature" refers to a temperature between 10 and 35°C, typically between 18 and 28°C. Ambient temperature is encompassed within the broader definition of "ambient conditions," which refers to the normal range of conditions in the surrounding environment to which a bio-based leather substitute or an intermediate in its manufacture is exposed or in which the manufacturing procedure for a bio-based leather substitute is carried out, i.e., the range of temperature, pressure, and atmospheric conditions to which a bio-based leather substitute or an intermediate in its manufacture is exposed during use, storage, and otherwise. This includes solar radiation, including X-rays, ultraviolet (UV), and infrared (IR) electromagnetic radiation. Typically, ambient conditions include temperatures between 10 and 35°C, pressures between 20 and 100 kPa, and the environment is typically an oxygen-containing atmosphere. [Example]

[0205] Example 1 A bio-based leather substitute material according to a first aspect of the present invention. Ground dried brewer's grains (<50 μm, 4.2 g) were added to a 0.1 M NaOH solution, heated to 90 °C, and stirred for 20 min. Glycerol (1.7 g) was added, followed by aliquots of citric acid until the solution was neutral (pH = 7). The solution was stirred for an additional 5 min, cast into a 10 x 10 cm silicon tray, and dried at ambient temperature for 16 h. The material was removed from the tray and dried in a spin dryer at 35 °C for an additional 3 h to produce a brown bio-based leather substitute material (surface area 10 cm). 2 , thickness 0.6 to 0.73 mm) was obtained.

[0206] Example 2 A bio-based leather substitute material according to a first aspect of the present invention. Ground dried brewer's grains (<50 μm, 4.2 g) and K-carrageenan (0.4 g) were added to 40 mL of 0.1 M NaOH solution, heated to 90 °C, and stirred for 25 minutes. Glycerol (1.79 g) was added, and aliquots of citric acid were added until the solution was neutral (pH = 7). The solution was stirred for an additional 5 minutes, cast into a 10 × 10 cm silicon tray, and dried at ambient temperature for 16 hours. The material was removed from the tray and dried in a spin dryer at 35 °C for an additional 3 hours to produce a brown bio-based leather substitute material (surface area 10 cm). 2 , thickness 0.81 to 0.87 mm) was obtained.

[0207] Example 3 A bio-based leather substitute according to a second aspect of the present invention. K-carrageenan (0.4 g), agar agar (0.4 g), sorbitol (0.085 g), CaCO3 (0.06 g), KCl (0.02 g), and glycerol (0.3 g) were dissolved in 40 mL of distilled water. The mixture was heated to 95 °C and stirred for 30 minutes, then cooled to 60 °C. Ground dried brewer's grains (<50 μm, 3.5 g), tannic acid (0.3 g), and citric acid (0.05 g) were then added. The solution was stirred at 60 °C for 5 minutes, cast into a 10 × 10 cm silicon tray, and dried at ambient temperature for 16 hours. The material was removed from the tray and dried in a spin dryer at 35 °C for an additional 3 hours, resulting in a brownish-brown material (surface area 10 cm). 2 The thickness was 0.93 to 0.95 mm and the tensile strength was 49.9 MPa.

[0208] Example 4 Dried brewer's spent grains were sieved through a fine mesh to remove non-grain debris and washed with distilled water (400 ml x 3). The washed brewer's spent grains were added to 0.1 M NaOH solution (1200 ml) and stirred at 72 °C for 1 hour. The solution was filtered to separate insoluble components. Then, 0.2 M citric acid solution (30 mL) was slowly added to slowly lower the solution's pH to 7. After cooling to ambient temperature at 45 °C, transglutaminase (Stabizym® ​​TGL, 0.6 g) and nanocellulose (0.315 g) were added. The solution was sonicated for 7 minutes to ensure uniform mixing and stirred for 16 hours. Glycerol (8.34 g) was added, and the solution was heated to 72 °C for 2.5 hours before being cast into two silicone trays (20 cm x 25 cm). The cast solution was allowed to dry under ambient conditions, resulting in two sheets (0.4 mm thick) of brown bio-based leather substitute material according to the first aspect of the present invention. One sheet was sprayed with dilute citric acid (adhesive / crosslinker) and placed on top of the other sheet to bond the sheets together, forming a construct according to the third aspect of the present invention (0.8 mm thick, tensile strength 7.1 MPa). One of the sheets was then embossed. This construct was then formed into a molded card holder article according to the fifth aspect of the present invention.

[0209] Example 5 Dried brewer's spent grains (150.4 g, provided by Kernel Brewery) were sieved through a mesh to remove non-grain debris and washed with distilled water (1000 ml x 3). The washed brewer's spent grains were added to 0.1 M NaOH solution (1200 ml) and stirred at 70 °C for 1 hour. The solution was filtered to separate the insoluble components, and 500 ml was reserved for this experiment. The pH was then slowly lowered to 7 by the slow addition of 0.1 M HCl solution and heated to 72 °C for an additional 2.5 hours.

[0210] This solution was divided into three aliquots, A, B, and C, of ​​80 mL each. (A) 1 g of glycerol was added to Solution A, mixed for 5 minutes, and then cast into two square silicone molds (10 cm x 10 cm). The solution was allowed to dry at ambient conditions (20°C), resulting in two sheets of brown bio-based leather substitute material according to the first aspect of the present invention (thickness 0.28 mm, modulus (elongation under load) 18.3%, tensile strength 3.74 MPa).

[0211] (B) 1 g of glycerol and 0.127 g of citric acid were added to Solution B, mixed for 5 minutes, and then cast into two square silicone molds (10 cm x 10 cm). The solution was allowed to dry at ambient conditions (20°C), resulting in two sheets of brown bio-based leather substitute material according to the first aspect of the present invention (0.28 mm thick, 20.2% modulus (elongation under load), and 4.44 MPa tensile strength).

[0212] (C) 1 g of glycerol and 0.124 g of citric acid were added to Solution B and mixed for 5 minutes. The solution was cooled to below 55°C, after which transglutaminase (0.133 g) was added. After stirring for 5 minutes, the solution was cast into two square silicone molds (10 cm x 10 cm). The solution was allowed to dry at ambient conditions (20°C), resulting in two sheets of brown bio-based leather substitute material according to the first aspect of the present invention (thickness 0.28 mm, modulus (elongation under load) 23.7%, tensile strength 5.47 MPa).

[0213] Example 6 Dried brewer's grains (150.6 g, provided by Kernel Brewery) were sieved through a mesh to remove non-grain fragments and washed with distilled water (750 mL x 3). The washed brewer's grains were added to 0.1 M NaOH solution (1200 mL) and stirred at 72 °C for 1 hour. The solution was filtered to separate insoluble components. The pH of the solution was then slowly lowered to 7.4 by the slow addition of 0.2 M citric acid solution. After cooling to ambient temperature at 35 °C, transglutaminase (0.67 g) and Ca(OH)2 (0.62 g) were added. The pH was slowly returned to 7.4 by the slow addition of 0.2 M citric acid solution, and the solution was stirred for 16 hours. Nanocellulose (15.4 g) and glycerol (3.1 g) were added and stirred for 5 minutes. The solution was cast into a square silicone mold (20 cm x 20 cm) and allowed to dry at ambient conditions (20°C), resulting in the formation of a sheet of brown bio-based leather substitute material according to the first aspect of the present invention (0.45 mm thick, 12.1% modulus (elongation under load), and 9.76 MPa tensile strength).

[0214] Embodiment 1. A bio-based leather alternative material containing a protein extract and cross-linking agent derived from brewer's grain or distiller's grain. 2. The bio-based leather substitute material of embodiment 1, wherein said bio-based leather substitute material further comprises an isolated algal polysaccharide or a salt thereof, preferably an isolated algal polysaccharide. 3. The bio-based leather substitute material of embodiment 2, wherein the isolated algal polysaccharide 1. A bio-based leather substitute material, wherein the isolated algal polysaccharide is selected from isolated algin, isolated alginic acid, isolated fucoidan, isolated laminarin, isolated agar agar, isolated carrageenan, isolated ulvan, or a combination thereof, preferably the isolated algal polysaccharide is an anionic polysaccharide, more preferably the isolated algal polysaccharide is isolated carrageenan or isolated agar agar, or a combination thereof. 4. The bio-based leather substitute according to any one of embodiments 1 to 3, wherein the protein extract is a protein isolate. 5. A bio-based leather alternative material in which brewer's grains or distiller's grains contain proteins, cross-linking agents and isolated algal polysaccharides or salts thereof. 6. The bio-based leather substitute material of embodiment 5, wherein the bio-based leather substitute material further comprises an isolated algal polysaccharide or a salt thereof, preferably an isolated algal polysaccharide. 7. The bio-based leather substitute according to embodiment 5 or 6, wherein the isolated algal polysaccharide is selected from isolated algin, isolated alginic acid, isolated fucoidan, isolated laminarin, isolated agar agar, isolated carrageenan, isolated ulvan, or a combination thereof, preferably the isolated algal polysaccharide is an anionic polysaccharide, more preferably the isolated algal polysaccharide is isolated carrageenan or isolated agar agar, or a combination thereof. 8. The bio-based leather substitute material according to any one of embodiments 1 to 7, wherein the crosslinking agent is a naturally derived crosslinking agent, preferably selected from citric acid, formaldehyde, acetone, urea, gum arabic, alginic acid, genipin, transglutaminase, azetidinium, rosin, isosorbide, tannic acid, gallic acid, ellagic acid, ferulic acid, caffeic acid, vanillin, or a combination thereof, more preferably selected from citric acid, formaldehyde, acetone, urea, gum arabic, alginic acid, genipin, transglutaminase, azetidinium, rosin, isosorbide, tannic acid, gallic acid, ellagic acid, ferulic acid, caffeic acid, vanillin, or a combination thereof. a bio-based leather substitute selected from transglutaminase, azetidinium, rosin, isosorbide, tannic acid, gallic acid, ellagic acid, ferulic acid and caffeic acid, or a combination thereof, more preferably selected from citric acid, urea, gum arabic, alginic acid, genipin, transglutaminase, rosin, isosorbide, tannic acid, gallic acid, ellagic acid, ferulic acid, caffeic acid, or a combination thereof, more preferably selected from citric acid and tannic acid, or a combination thereof. 9. The bio-based leather substitute according to any one of embodiments 1 to 8, wherein the bio-based leather substitute further comprises a plasticizer, preferably a naturally derived plasticizer, more preferably selected from glycerol, ethylene glycol, acetic acid, water, ethanol, glycol, fatliquor, sorbitol, sorbitan, didecyldimethylammonium chloride (DDAC), polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oils, and acetylated monoglycerides, more preferably selected from glycerol, acetic acid, water, ethanol, fatliquor, sorbitol, sorbitan, polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oils, and acetylated monoglycerides, more preferably glycerol, water, or a combination thereof. 10. The bio-based leather substitute according to any one of embodiments 1 to 9, wherein the protein is derived from brewer's grains. 11. The bio-based leather substitute according to any one of embodiments 1-10, wherein the brewer's spent grain or distiller's grain is a protein-containing grain by-product of beer or distiller's spirits production, preferably the brewer's spent grain or distiller's grain comprises 5-40 wt. % protein, optionally 1-15 wt. % lipid, optionally 5-35 wt. % lignin, and optionally 20-60 wt. % cellulose, based on the dry weight of the brewer's spent grain or distiller's grain. 12. A multilayer construct comprising the bio-based leather substitute material according to any one of embodiments 1 to 11 and a scaffold support, preferably provided as a layer of the multilayer construct, and preferably a multi-layer construct, wherein the scaffold support is selected from cotton, viscose, natural cellulosic fibers, perforated mesh, mesh, cheesecloth, linen, or muslin mesh. 13. An article formed from the bio-based leather substitute material of any one of embodiments 1-11, or the multi-layer construction of embodiment 12. 14. A method of forming a bio-based leather substitute material according to any of embodiments 1-4, and embodiments 8, 9, 10, or 11 depending therefrom, the method comprising providing a protein extract derived from brewer's spent grains or distiller's grains and combining with a cross-linking agent to form the bio-based leather substitute material. 15. The method of embodiment 14, wherein the method comprises obtaining a protein extract derived from brewer's spent grains or distiller's grains, and providing the protein extract derived from brewer's spent grains or distiller's grains and combining it with a cross-linking agent to form a bio-based leather substitute material. 16. The method of embodiment 14, wherein the method comprises obtaining a protein extract from brewer's spent grains or distiller's grains, separating the protein extract and optionally purifying the protein extract to provide a protein isolate, and providing the brewer's spent grains or distiller's grains-derived protein isolate and combining it with a cross-linking agent to form a bio-based leather substitute material. 17. The method according to embodiment 15 or 16, wherein the protein extract is obtained by alkaline extraction, ethanol extraction, organic solvent extraction, acid extraction, salt solution extraction, hot water extraction, enzymatic extraction or sonication (ultrasound-assisted extraction), preferably by alkaline extraction, more preferably alkaline extraction in solution, more preferably using an alkaline reagent selected from NaOH, KOH or Ca(OH)2 in aqueous solution, preferably at 0.05-1 M, for example 0.1 M, optionally at a temperature of 50-95°C, preferably 55-95°C. 18. The method according to embodiment 16 or 17, wherein the protein is separated by filtration and / or centrifugation. 19. The method of any of embodiments 14-18, wherein the bio-based leather substitute material further comprises an isolated algal polysaccharide or a salt thereof, and the method further comprises heat treating the isolated algal polysaccharide or salt thereof. 20. The method according to embodiment 19, wherein the heat treatment is carried out in a solution at a temperature of 80°C or higher, for example 80 to 100°C, preferably 80 to 98°C, more preferably 80 to 95°C, and the solution is preferably an aqueous solution, more preferably water or distilled water. 21. A method of forming a bio-based leather substitute material according to any of embodiments 5-11, the method comprising the steps of subjecting the isolated algal polysaccharide or salt thereof to a heat treatment and combining it with protein-containing brewer's spent grain or distiller's spent grain, and a crosslinking agent to form the bio-based leather substitute material. 22. The method according to embodiment 21, wherein the heat treatment is carried out in a solution at 80°C or higher, for example, 80 to 100°C, preferably 80 to 98°C, more preferably 80 to 95°C, and the solution is preferably an aqueous solution, more preferably water or distilled water. 23. The method according to any of embodiments 14 to 22, wherein the brewer's or distiller's grains are dried and preferably chopped or ground, preferably ground, before use. 24. Use of brewer's grains or distiller's grains in the production of a bio-based leather substitute material according to any one of embodiments 1 to 11.

Claims

1. A bio-based leather alternative material comprising a reaction product of a protein extract derived from brewer's grains or distiller's grains and a cross-linking agent.

2. 2. The bio-based leather substitute material of claim 1, wherein the cross-linking agent is a cross-linking reagent and / or a cross-linking catalyst, and preferably the bio-based leather substitute material comprises the reaction product of the sequential reaction of a protein extract derived from brewer's spent grains or distiller's spent grains with a cross-linking reagent and a cross-linking catalyst.

3. The cross-linking reagent is a naturally occurring cross-linking reagent, and is preferably selected from citric acid, sebacic acid, formaldehyde, glutaraldehyde, benzaldehyde, oxalic acid, phosphoric acid, glucuronic acid, fumaric acid, benzoic acid, ascorbic acid, tartaric acid, maleic acid, tyrosine, riboflavin, bis(sulfosuccinimidyl)suberic acid, N-hydroxysulfosuccinimide, urea, genipin, azetidinium, isosorbide, tannic acid, gallic acid, malic acid, ellagic acid, ferulic acid, caffeic acid, vanillin, or a combination thereof, and more preferably selected from citric acid, formaldehyde, urea, gum arabic, alginic acid, genipin, azetidinium, rosin ....

3. The bio-based leather substitute material of claim 2, wherein the bioactive agent is selected from an aldehyde, urea, gum arabic, alginic acid, genipin, azetidinium, rosin, isosorbide, tannic acid, gallic acid, malic acid, ellagic acid, ferulic acid, caffeic acid, or a combination thereof, more preferably selected from citric acid, malic acid, formaldehyde, urea, gum arabic, alginic acid, genipin, azetidinium, rosin, isosorbide, tannic acid, gallic acid, ellagic acid, ferulic acid, caffeic acid, or a combination thereof, more preferably selected from citric acid, malic acid, urea, gum arabic, alginic acid, genipin, rosin, isosorbide, tannic acid, gallic acid, ellagic acid, ferulic acid, caffeic acid, or a combination thereof, more preferably selected from citric acid, malic acid, tannic acid, or a combination thereof.

4. 4. The bio-based leather substitute material according to claim 2 or 3, wherein the cross-linking catalyst is an enzyme, preferably the cross-linking catalyst is an enzyme selected from transglutaminase, lysyl oxidase and laccase, or a combination thereof, more preferably the cross-linking catalyst is transglutaminase.

5. A bio-based leather alternative material comprising a protein extract derived from brewer's grains or distiller's grains and a plasticizer.

6. The bio-based leather substitute material according to any one of claims 1 to 5, wherein the protein extract is a protein isolate.

7. The bio-based leather substitute material further comprises a plasticizer, preferably a naturally derived plasticizer, more preferably the plasticizer is selected from glycerol, water, ethylene glycol, polyethylene glycol, propylene glycol, lecithin, sunflower lecithin, mannitol, xylitol, diethylene glycol, tetraethylene glycol, ethanolamine, triethanolamine, acetic acid, glycol, fatliquoring agent, sugar alcohol such as sorbitol, sorbitan, didecyldimethylammonium chloride (DDAC), polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oil, acetylated monoglyceride, or a combination thereof, more preferably the plasticizer is selected from glycerol, ethylene glycol, acetic acid, water, ethanol, glycol, fatliquoring agent, sugar alcohol such as sorbitol, sorbitan, didecyldimethylammonium chloride (DDAC), polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oil, acetylated monoglyceride, or a combination thereof.

7. The bio-based leather substitute material of any of claims 1 to 4 or 6, wherein the plasticizer is selected from glycerol, acetic acid, water, ethanol, a fatliquoring agent, a sugar alcohol such as sorbitol, sorbitan, Polysorbate 20, Polysorbate 80, erythritol, triethyl citrate, an epoxidized oil, an acetylated monoglyceride, or a combination thereof, more preferably selected from epoxidized oil, glycerol, water, or a combination thereof, more preferably selected from glycerol, water, or a combination thereof.

8. The plasticizer is a naturally occurring plasticizer, and preferably the plasticizer is selected from glycerol, ethylene glycol, polyethylene glycol, propylene glycol, lecithin, sunflower lecithin, mannitol, xylitol, diethylene glycol, tetraethylene glycol, ethanolamine, triethanolamine, acetic acid, glycol, fatty liquid, sugar alcohol such as sorbitol, sorbitan, didecyldimethylammonium chloride (DDAC), polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oil, and acetylated monoglyceride, and more preferably the plasticizer is selected from glycerol, ethylene glycol, acetic acid, ethanol, glycol, fatty liquid, sugar alcohol such as sorbitol, sorbitan, didecyldimethylammonium chloride (DDAC), polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oil, and acetylated monoglyceride.

10. The bio-based leather substitute material of claim 5, or claim 7 dependent thereon, wherein the plasticizer is selected from thritol, triethyl citrate, epoxidized oils, acetylated monoglycerides, or combinations thereof, more preferably a polyol-based plasticizer, more preferably the plasticizer is selected from glycerol, ethylene glycol, polyethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, sugar alcohols such as sorbitol, sorbitan, erythritol, or combinations thereof, more preferably glycerol, acetic acid, ethanol, fatty liquids, sugar alcohols such as sorbitol, sorbitan, polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oils, acetylated monoglycerides, more preferably glycerol.

9. The bio-based leather substitute material according to any one of claims 1 to 8, wherein the protein extract is derived from brewer's grains.

10. 10. The bio-based leather substitute material of any of claims 1 to 4, 6, 7, or 9, further comprising an isolated algal polysaccharide or a salt thereof, preferably isolated algal polysaccharide, more preferably said isolated algal polysaccharide is selected from isolated algin, isolated alginic acid, isolated fucoidan, isolated laminarin, isolated agar agar, isolated carrageenan, and isolated ulvan, or a combination thereof, more preferably said isolated algal polysaccharide is an anionic polysaccharide, more preferably said isolated algal polysaccharide is isolated carrageenan or isolated agar agar, or a combination thereof.

11. 11. A construct comprising two or more layers of the bio-based leather substitute material according to any one of claims 1 to 10, or the bio-based leather substitute material according to any one of claims 1 to 10 and a scaffold support, preferably wherein the scaffold support is selected from cotton, viscose, natural cellulosic fibres, perforated mesh, mesh, cheesecloth, linen or muslin mesh.

12. An article formed from the bio-based leather substitute material of any of claims 1 to 10, or the construct of claim 11.

13. 11. A method of forming the bio-based leather substitute material of any of claims 1-4, 6, 7, 9 or 10, comprising providing a protein extract derived from brewer's spent grains or distiller's spent grains, combining with a cross-linking agent, and forming the bio-based leather substitute material.

14. 10. A method of forming a bio-based leather substitute material according to claim 5 or 8 or any of claims 6 or 9 depending therefrom, comprising providing a protein extract derived from brewer's spent grains or distiller's spent grains, combining with a plasticizer, and forming a bio-based leather substitute material.

15. 15. The method of claim 13 or 14, further comprising separating and optionally purifying the protein extract from one or more other components of the brewer's grains or distiller's grains to provide a brewer's grains or distiller's grains-derived protein isolate, preferably wherein the protein extract is separated by filtration and / or centrifugation, more preferably by filtration.

16. Alkaline extraction, ethanol extraction, organic solvent extraction, acid extraction, salt solution extraction, hydrothermal extraction, enzymatic extraction or ultrasonic treatment (ultrasound-assisted extraction), preferably alkaline extraction, preferably an alkaline reagent in aqueous solution, preferably NaOH, KOH or Ca(OH) in aqueous solution ２ 16. The method according to any of claims 13 to 15, comprising obtaining a protein extract by alkaline extraction using an alkaline reagent selected from the group consisting of:

17. 17. The method of any of claims 13, 15 or 16, wherein the bio-based leather substitute material further comprises isolated algal polysaccharides or salts thereof, and wherein the method further comprises heat treatment of the isolated algal polysaccharides or salts thereof, preferably carried out in a solution at a temperature of 80°C or above, such as 80-100°C, preferably 80-98°C, more preferably 80-95°C, and wherein the solution is preferably an aqueous solution, more preferably water or distilled water.

18. 18. The method of any of claims 13 to 17, wherein the bio-based leather substitute material can be formed by casting, solution casting, thermal extrusion, thermal compression molding or calcination, die casting, pultrusion, electrospraying, wet spinning, dry spinning, melt spinning and gel spinning, preferably casting, solution casting, thermal extrusion, thermal compression molding or calcination, preferably solution casting.

19. 19. The method according to any of claims 13 and 15 to 18, wherein for combining the protein extract with a cross-linking agent, the protein extract derived from brewer's grains or distiller's spent grains is combined with a cross-linking reagent and / or a cross-linking catalyst, preferably both a cross-linking reagent and a cross-linking catalyst, more preferably the protein extract derived from brewer's grains or distiller's spent grains is reacted with a cross-linking agent and then with a cross-linking catalyst in a sequential reaction, more preferably the method comprises the steps of combining the protein extract derived from brewer's grains or distiller's spent grains with a cross-linking reagent and combining the resulting product with a cross-linking catalyst.

20. 20. The method of any of claims 13 and 15-19, wherein a plasticizer and / or one or more additional ingredients are introduced after providing the protein extract derived from brewer's spent grains or distiller's spent grains and before forming the bio-based leather substitute material, preferably before, during and / or after combining the protein extract with the crosslinking agent.

21. The plasticizer is a naturally occurring plasticizer, and is preferably glycerol, ethylene glycol, or the like. The plasticizer is selected from the group consisting of glycerol, polyethylene glycol, propylene glycol, lecithin, sunflower lecithin, mannitol, xylitol, diethylene glycol, tetraethylene glycol, ethanolamine, triethanolamine, acetic acid, glycol, fatliquoring agents, sugar alcohols such as sorbitol, sorbitan, didecyldimethylammonium chloride (DDAC), polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oils, and acetylated monoglycerides, and more preferably, the plasticizer is selected from the group consisting of glycerol, ethylene glycol, acetic acid, ethanol, glycol, fatliquoring agents, sugar alcohols such as sorbitol, sorbitan, didecyldimethylammonium chloride (DDAC), polysorbate 20, polysorbate 80, erythritol, triethyl citrate, epoxidized oils, and acetylated monoglycerides.

19. The method of claim 14, or any of claims 15, 16 and 18 dependent thereon, wherein the additive is selected from an epoxidized oil, an acetylated monoglyceride, or a combination thereof, more preferably a polyol-based plasticizer, more preferably selected from glycerol, ethylene glycol, polyethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, a sugar alcohol such as sorbitol, sorbitan, erythritol, or a combination thereof, more preferably selected from glycerol, acetic acid, ethanol, a fatliquor, a sugar alcohol such as sorbitol, sorbitan, polysorbate 20, polysorbate 80, erythritol, triethyl citrate, an epoxidized oil, an acetylated monoglyceride, more preferably glycerol.

22. 21. The method of any of claims 13 and 15-20, comprising a neutralization step after providing the protein extract from brewer's or distiller's grains and before forming the bio-based leather substitute material, preferably before combining the protein extract from brewer's or distiller's grains with the cross-linking agent.

23. 22. The method of claim 14 and any of claims 15, 16, 18 or 21 dependent thereon, comprising a neutralization step after providing the protein extract derived from brewer's or distiller's grains and prior to forming the bio-based leather substitute material, preferably prior to combining the protein extract derived from brewer's or distiller's grains with the plasticizer.

24. 23. The method of any of claims 13, 15-20 or 22, further comprising heat treatment and / or ultrasonic treatment prior to formation of the bio-based leather substitute material, preferably comprising heat treatment and ultrasonic treatment, optionally wherein the heat treatment comprises heating to a temperature of 50-100°C.

25. 24. The method of claim 14 and any of claims 15, 16, 18, 21 or 23 dependent thereon, further comprising a heat treatment and / or an ultrasonic treatment prior to forming the bio-based leather substitute material, preferably comprising a heat treatment and an ultrasonic treatment, optionally wherein the heat treatment comprises heating to a temperature of 50-100°C, preferably wherein the heat treatment and / or ultrasonic treatment occurs after combining the protein extract derived from brewer's spent grain or distiller's spent grain with the plasticizer.

26. 26. A bio-based leather substitute material obtainable by the method of any one of claims 13 to 25, comprising a reaction product of a protein extract derived from brewer's spent grains or distiller's spent grains and a crosslinking agent.

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