Process for the production of biogas from a fibrous substrate

Abstract

Disclosed is a process for producing biogas from a fibrous substrate, involving biologically pretreating a woven, non-woven or agglomerated, and shredded fibrous substrate, by solid fermentation using one or more filamentous fungal strains, more particularly one or more saprophytic filamentous strains, producing biogas from the pretreated fibrous substrate with formation of a digestate, and collecting the digestate.

Description

[0001] PROCESS FOR PRODUCING BIOGAS FROM FIBROUS SUBSTRATE

[0002] The present invention relates to a process for producing biogas from fibrous substrate comprising:

[0003] Biological pretreatment of the fibrous substrate forming a biologically pretreated fibrous substrate

[0004] Transfer of biologically pretreated fibrous substrate into a biogas production facility

[0005] Production of biogas from pre-treated fibrous substrate with formation of digestate,

[0006] A collection of digestate,

[0007] Such biogas production processes are well known in the state of the art, as for the production of biogas from plant waste or wood waste.

[0008] In this case, biological pretreatment was implemented to replace mechanical or chemical pretreatments and is a pretreatment of the waste using enzymes to facilitate attack by methanogenic microorganisms in the biogas production plant.

[0009] Indeed, mechanical / physical or chemical pretreatments are often necessary to achieve biogas production yields that make the installation profitable. Unfortunately, these remain consumers of energy resources (grinding, heating, pressurization) or products such as bases, sometimes strong, acids to carry out preliminary attacks on the waste. In the case of chemical treatments, even if major efforts have been made to recycle these basic and acidic liquid flows, these treatments remain water-consuming and generate liquid phases that must also be treated. In addition, the pretreated waste must often be further treated before it can enter the biogas production facility (neutralization, heat treatment, etc.).It is for these reasons, among others, that some authors have turned to biological pre-treatments using enzymes, which have proven to be quite effective in increasing biogas production from waste, but generate a significant additional production cost. Enzymes are indeed relatively expensive substances, and to function optimally also require fairly strict temperature and pH conditions, which make their industrial use perilous and little deployed today for most substrates usable for biogas production. The authors generally report their use for complex substrates, where the carbonaceous material is not very accessible to bacteria in the biogas production facility.

[0010] Among the substrates where carbonaceous material is not easily accessible, we find wood waste, but also textile waste which has become a huge issue in waste management.

[0011] In 2021, more than 149 million tons of textiles were produced worldwide. In Europe, textile consumption has increased by more than 40% over the last two decades, and it is estimated that each inhabitant throws away an average of 1.1 kg of textiles per year. Only 38% of textile waste is collected and sorted for potential reuse, and it is estimated that only 1% is recycled and 87% is incinerated or buried in landfills.

[0012] One of the major problems with textile waste lies in its diversity. There are not only different types of waste, but also many different types of textiles, and within these, many different types of fibers that are mixed to form textiles.

[0013] While there are currently some solutions for textile production waste (cutting waste, defective materials, production residue, etc.), the nature of which is well known and controlled, certain types of textile waste are extremely problematic for recycling.

[0014] For the moment, for textiles from clothing, existing solutions consist of mechanical sorting to recover clothes that can be sold second-hand, and for the remaining fraction, a more advanced sorting of separation of fabrics according to their composition is carried out manually or by optical fiber. Textile waste from furniture is not currently recovered and is used for its calorific potential.

[0015] On the other hand, the mixtures of synthetic and natural fibres found in ticking and other net curtains constitute a source of plastic fibres which cannot be exploited by existing techniques, despite the existence of physico-chemical treatments which can weaken the natural fibres in order to make them possible to spin.

[0016] Furthermore, while in some cases mattress ticking is isolated from the rest of the mattress, this is not always the case and this depends on the technology available to the waste recovery centers that are responsible for recycling. Also, some centers grind mattresses with their ticking, remove the metal parts and thus generate a shredded product comprising a mixture of shredded ticking and synthetic or natural foam.

[0017] The invention aims to overcome the disadvantages of the state of the art by providing a process for producing biogas that makes it possible to offer a recovery route for these complicated wastes such as mattress waste, upholstery waste, end-of-life textile waste, textile waste from furnishing fabrics, etc.

[0018] To solve this problem, the invention provides a method for producing biogas as indicated at the beginning, characterized in that the biological pretreatment of the fibrous substrate is a solid fermentation using one or more filamentous fungal strains, more particularly one or more saprophytic filamentous fungal strains, even more particularly chosen from the divisions of Basidiomycetes and Ascomycetes, of a woven, non-woven or agglomerated fibrous substrate, and shredded into pieces, where said biologically pretreated fibrous substrate is a fibrous substrate shredded into pieces colonized by said at least one fungal strain.

[0019] As can be seen, the method according to the present invention proposes a biological pre-treatment of the fibrous substrate which has several advantages. First of all, the pre-treatment by solid fermentation using one or more fungal strains makes it possible not to consume large quantities of water, not to consume large volumes of chemical substances or expensive reagents, and provides a structural solution without requiring colossal investment in infrastructure. Fungal strains are in fact recognized for their ability to digest compounds that are particularly difficult to access, or even particularly polluting or toxic, and their action makes it possible to open the fiber structures to facilitate the action of methanogenic microorganisms.In addition, the fungal strain(s) feed on carbonaceous materials for their growth and thus reduce the proportion of complex and inaccessible fibers in the fibrous substrate by producing a biomass that is easier to digest for methanogenic microorganisms, namely the mycelium and other compounds of the fungus. Therefore, the proportion of complex substrate to be digested on the accessible substrate is more favorable after pre-treatment with one or more fungal strains.

[0020] Avantageusement, in the procedure according to the present invention, you will find one or more powerful herbs including at the same time a highly suitable colonizer chosen in the group consisting of the genres Agrocybe, Ganoderma, Tra metes, Pycnoporus, Pleurotus, Fomes, Fomitopsis, Irpex, Laetiporus, Inonotus, Lentinula, Fusarium, Aspergillus, Trichoderma, Pénicillium, Cladosporium, Chaetomium, Acremonium. In particular, the following species are preferred: Agrocybe sp., G.anoderma sp., G. applanatum, G. boninense, G. lucidum, G. resinaceum, G. sessile, Trametes sp. ; Trametes hirsute, T. pubescens, T. suaveolens, T. versicolor, Pycnoporus sanguineus, Pleurotus sp., P. albidus, P. citrinopileatus, P. djamor, P. eryngii, P. ostreatus, P. ostraceus florida, P. ostraceus sajorcaju caju, P. salmoneostramineus, Fomes fomentarius, Fomitopsis pinicola, Irpex lacteus, Laetiporus sulphureus, Inonotus obliquus, Lentinula edodes; Lentinus lepideus, L. giganteus, L. squarrosulus and L.tigrinus, Fusarium sp., Fusarium culmorum, Fusarium solani, Aspergillus sp., Aspergillus oryzae, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Aspergillus terreus, Trichoderma sp., Trichoderma reesei, Trichoderma viride, Trichoderma longibrachiatum, Cladosporum sp., Chaetomium sp., Chaetomium globosum. This allows for fungal strains that spread widely and provide a large amount of usable biomass for methanogenic microorganisms either for methane production or as a culture substrate. In addition, during their colonization, the fungal strains utilize the carbonaceous material present in the fibrous substrate and begin digesting the fibrous substrate. In this way, said at least one fungal strain allows the conversion of poorly accessible carbonaceous material into carbonaceous material more easily accessible for methanogenic microorganisms.

[0021] In the advanced manner of the present invention, you will find one or more natural herbs including many a natural ingredient producing selected enzymes in the group consisting of herbs belonging to the Agrocybe genre, Ganoderma, Trametes, Pycnoporus, Pleurotus, Pomes, Fomitopsis, Irpex, Laetiporus, Inonotus, Lentinula, Fusarium, Aspergillus, Trichoderma, Pénicillium, Cladosporium, Chaetomium, Acremonium, more particulièrement choisie parmi les souches Agrocybe sp., Ganoderma sp., G. applanatum, G. boninense, G. lucidum, G. resinaceum, G. sessile, Trametes sp. ; Trametes hirsute, T. pubescens, T. suaveolens, T. versicolor, Pycnoporus sanguineus, Pleurotus sp., P. albidus, P. citrinopileatus, P. djamor, P. eryngii, P. ostreatus, P. ostraceus florida, P. ostraceus sajorcaju caju, P. salmoneostramineus, Fomes fomentarius, Fomitopsis pinicola, Irpex lacteus, Laetiporus sulphureus, Inonotus obliquus, Lentinula edodes; Lentinus lepideus, L. giganteus, L.squarrosulus and L. tigrinus, Fusarium sp., Fusarium culmorum, Fusarium solani, Aspergillus sp., Aspergillus oryzae, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Aspergillus terreus, Trichoderma sp., Trichoderma reesei, Trichoderma viride, Trichoderma longibrachiatum, Cladosporum sp., Chaetomium sp., Chaetomium globosum. The enzymes produced in this case can have different uses, either they contribute to the degradation of the fibrous substrate, or the enzymes are co-products of the fungal attack of the fibrous substrate that can be collected and then purified for further commercialization.

[0022] In some cases, according to the present invention, it is contemplated that said one or more fungal strains is a mixture of one or more high colonizing strains and one or more enzyme-producing strains.

[0023] In the context of the present invention, by "biogas" is preferably meant a biogenic gas, preferably a gas comprising methane, optionally other gases which can be used as fuel, and carbon dioxide, the latter being advantageously post-treated (trapping, supercritical extraction, reaction to form other molecules).

[0024] In a preferred embodiment according to the present invention, wherein the agglomerated, woven or non-woven shredded fibrous substrate comprises fibers chosen from natural plant or animal textile fibers, semi-synthetic textile fibers or polymer textile fibers, lignocellulosic fibers.

[0025] The term “natural plant textile fibers” means, within the meaning of the present invention, natural textile fibers of abaca, bagasse, bamboo, coconut, cotton, linen, hemp, jute, raffia, Ramie, rattan, wood, Furcraea andina, Ceiba pentandra, Agave sisalana, Kenaf, Pina, and the like.

[0026] The term natural animal textile fibres means natural textile fibres of alpaca, angora, byssus, camel hair, cashmere, catgut, guanaco, hair or fur, llama, mohair, pashmina, qiviuk, silk, possibly spider silk, sinew, wool, yak vicuña and the like,

[0027] For the purposes of the present invention, the term semi-synthetic fibers means fibers of cellulose acetate, cellulose diacetate, cellulose triacetate, lyocell, Modal and the like.

[0028] The term polymer textile fibers means acrylic fibers, aramid fibers (Twaron, Kevlar, Nomex, Technora), microfibers, polyamide fibers, polyester fibers, polyolefin fibers, high molecular weight polyethylene fibers, elastane fibers, vectran fibers, vinalon fibers, zylon fibers and the like. This classification was published by Weidmann in 2010.

[0029] For the purposes of the present invention, the term lignocellulosic fibres means fibres composed of lignin, hemicellulose and cellulose in varying proportions, derived from forestry and agricultural operations as well as waste (furniture wood, chipboard, etc.).

[0030] The terms “shredded fibrous substrate, formed from said fibers in agglomerated, woven or non-woven form”, or “fibrous substrate in the form of pieces or granules formed from said fibers in agglomerated, woven or non-woven form”, mean agglomerated, woven or non-woven fibers, typically textile or lignocellulosic, which have undergone a size reduction step to form pieces. This size reduction may include grinding by a scissor crusher, a guillotine-type cutter, a shredder, a jaw crusher, or even a shredder. This grinding step is prior to the supply of fibrous substrate.In some cases, before the humidification step, the present invention also contemplates carrying out an additional size reduction step if this proves useful, for example when the fibrous substrate in the form of lumps or granules formed from said fibers has too broad a size distribution or when the average size of the lumps is too high.

[0031] Advantageously, said fibrous substrate in agglomerated, woven or non-woven form is a residue from the grinding of recycled textiles, more particularly recycled furnishing textiles, recycled mattresses, bathroom or bed linen, clothing textiles, textile production scraps or waste, upholstery and their mixtures.

[0032] By the terms upholstered, we mean products such as cushions, sofa seats, soft toys, namely products typically containing a mixture of textile material and upholstery foam.

[0033] More particularly, according to the present invention, said fibrous substrate in agglomerated, woven or non-woven form is a residue from the grinding of recycled textiles chosen from furnishing, mattress and upholstery textiles and has a synthetic foam content of between 10 and 80%.

[0034] In a further embodiment according to the present invention, said fibrous substrate in agglomerated, woven or non-woven form is a residue from the grinding of lignocellulosic elements, such as for example residue from the grinding of agglomerated wood.

[0035] In a preferred embodiment of the present invention, said fibrous substrate comprises a proportion of synthetic fibers, semi-synthetic fibers, synthetic foam, such as for example PU foam, and natural plant or animal fibers, and in which the collected digestate is enriched with synthetic fibers and plastic materials at a rate of more than 85% by weight relative to the weight of digestate.

[0036] In another preferred embodiment according to the present invention, the biological pretreatment step comprises:

[0037] - conditioning said fibrous substrate to obtain a conditioned fibrous substrate containing from 60 to 80% by weight of water relative to the weight of conditioned fibrous substrate, hygienization of said conditioned fibrous substrate to form a hygienized conditioned fibrous substrate, cooling of the hygienized conditioned fibrous substrate for a period of time between 12 and 24 hours, seeding of said hygienized conditioned fibrous substrate using mycelial spawn from said one or more fungal strains on seeds by adding at least one mycelial spawn on seeds to said hygienized conditioned fibrous substrate at a rate of 0.5% to 10% by weight, more particularly 1 to 7%, more particularly still 3 to 5% by weight of mycelial spawn relative to the weight of hygienized conditioned fibrous substrate, with obtaining seeded hygienized conditioned fibrous substrate,a mixture of said seeded hygienized conditioned fibrous substrate with obtaining a homogenized seeded hygienized conditioned fibrous substrate, an incubation of said homogenized seeded hygienized conditioned fibrous substrate for a period of time between 1 and 6 weeks, more particularly between 2 and 5 weeks, in an enclosure having a relative humidity between 65 and 85%, more particularly between 70 and 80%, a collection of a fibrous substrate colonized by said one or more fungal strains forming said biologically pretreated fibrous substrate.,

[0038] Alternatively to, or in addition to, mycelial spawn, a liquid culture of said one or more strains of mushroom is used for seeding.

[0039] In this case, the concentration for seeding will advantageously be determined by the person skilled in the art, taking into account the concentration of the starting liquid culture and the growth capacities of the strain on the fibrous substrate to be treated. Typically between 1 and 5% (weight by weight) of the liquid medium is used for seeding the sanitized conditioned fibrous substrate.

[0040] Advantageously, in the method according to the present invention, said hygienization of the conditioned fibrous substrate is a pasteurization to obtain the conditioned fibrous substrate hygienized for a period of at least 3 hours, preferably at least 4 hours, more preferably at least 5 hours at a temperature greater than or equal to 72°C.

[0041] More particularly, in the method according to the present invention, the pasteurization is carried out at increasing temperature until a temperature peak of greater than 85°C is obtained, more particularly 88°C, more particularly 90°C, maintained for a period of time of between 5 and 50 minutes, more particularly 30 and 40 min. In a variant according to the present invention, said hygienization of the conditioned fibrous substrate is a composting comprising at least one composting cycle comprising a step of increasing the temperature until a temperature of between 55 and 80°C is obtained, more preferably until a temperature of between 58 and 65°C is obtained, for a period of time of between 6 hours and 5 days, followed by a step of aerating said fibrous substrate to maintain a temperature of between 46 and 49°C for 3 to 7 days, optionally by turning the fibrous substrate over.

[0042] In a preferred embodiment according to the present invention, said step of conditioning said fibrous substrate to obtain a conditioned fibrous substrate comprises moistening the fibrous substrate and / or washing said fibrous substrate optionally followed by draining or drying.

[0043] In yet another preferred embodiment according to the present invention, said step of conditioning said fibrous substrate comprises an additional step of supplementing with essential elements, such as for example minerals (calcium, magnesium), phosphorus, carbon and nitrogen sources, typically to obtain a fibrous substrate whose carbon: nitrogen ratio is between 10 and 30, preferably between 15 and 20, for example by adding grains.

[0044] In another variant according to the present invention, said hygienization of the conditioned fibrous substrate comprises at least 2, 3, 4, 5, 6, 7, 8, or even 10 consecutive composting cycles.

[0045] In an advantageous embodiment according to the present invention, the method comprises, simultaneously with the pretreatment, a production of biomolecules, collected in parallel, said one or more fungal strains comprising at least one biomolecule-producing strain.

[0046] In an advantageous embodiment of the present invention, said biomolecules are sugars or polysaccharides and wherein said at least one fungal strain comprises at least one sugar or polysaccharide producing strain selected from the group of strains of the genus Agrocybe, Ganoderma, Trametes, Pycnoporus, Pleurotus, Fomes, Fomitopsis, Irpex, Laetiporus, Inonotus, Lentinula, Fusarium, Aspergillus, Trichoderma, Penicillium, Cladosporium, Chaetomium, Acremonium.

[0047] The polysaccharides produced may for example, but are not limited to, α-glucans, [3-glucans, lentanins, lipopolysaccharides, PSK (polysaccharide Krestin), PSP (peptide polysaccharide), [3-d-glucans, glucuronoglucans,

[0048] In an advantageous embodiment according to the present invention, said biomolecules are biomolecules of therapeutic or pharmaceutical interest or their precursors such as for example antibiotics, antimitotics, antivirals, biosorbents, biosurfactants and in which said at least one fungal strain comprises at least one strain producing therapeutic biomolecules or usable in pharmaceutical processes such as for example antibiotics, antimitotics, antivirals, biosorbents, biosurfactants chosen from the group of strains of the genera Aspergillus, Trichoderma, Penicillium, Fusarium, Pleurotus, Pycnoporus, Trametes, Ganoderma.

[0049] For example, mushrooms of the genus Ganoderma are composed of triterpenoids and polysaccharides. Triterpenoids have been reported to have hepatoprotective, antihypertensive, hypocholesterolemic, antihistamine, antitumor, antiangiogenic, antiplatelet aggregation, and complement inhibitory effects. Triterpenoids include, for example, ganodermic acids, lucidenic acids, ganoderic acids, ganolucidic and applanoxidic acids, lucidimols A and B, ganodermanondiol, ganoderiol F, and gano-dermanontriol, lucidones. Polysaccharides, on the other hand, have been reported to also have antitumor effects through immunomodulation and antiangiogenesis.Polysaccharides also have a protective effect against free radicals and can reduce cell damage caused by mutagenic agents. Some polysaccharides have also been reported to have an anti-diabetic effect.

[0050] Tra metes versicolor extracts exhibit anti-radical, anti-oxidant, anti-bacterial and acetylcholinesterase inhibition activities.

[0051] Extracts of mushrooms of the genus Pleurotus exhibit therapeutic effects such as hypocholesterolemia, free radical scavenging, antioxidant, anti-atherogenic, anti-tumor and immunomodulatory effects. Mushrooms of the genus Pleurotus have for example been reported to contain triterpenoids such as 2,3,6,23-tetrahydroxy-urs-12-en-28 oic acid, 2,3,23-trihydroxyurs-12-en-28 oic acid and lupeol.

[0052] The pigments of fungi of the genus Pycnoporus have antiviral, antibacterial and anti-inflammatory properties.

[0053] Fungi of the genera Aspergillus, Trichoderma, and Penicillium have been reported to contain biosurfactants.

[0054] Fungi of the genera Penicillium, Acremonium and Aspergillus have been reported to secrete antibiotics such as penicillin and cephalosporin.

[0055] In another advantageous embodiment according to the present invention, said biomolecules are enzymes and wherein said at least one fungal strain comprises at least one enzyme-producing strain selected from the group of strains belonging to the genus Agrocybe, Ganoderma, Trametes, Pycnoporus, Pleurotus, Fomes, Fomitopsis, Irpex, Laetiporus, Inonotus, Lentinula, Fusarium, Aspergillus, Trichoderma, Penicillium, Cladosporium, Chaetomium, Acremonium, more particularly selected from the strains Agrocybe sp., Ganoderma sp., G. applanatum, G. boninense, G. lucidum, G. resinaceum, G. sessile, Trametes sp.; Trametes hirsute, T. pubescens, T. suaveolens, T. versicolor, Pycnoporus sanguineus, Pleurotus sp., P. albidus, P. citrinopileatus, P. djamor, P. eryngii, P. ostreatus, P. ostraceus florida, P. ostraceus sajorcaju caju, P.salmoneo-stramineus, Fomes fomentarius, Fomitopsis pinicola, Irpex lacteus, Laetiporus sulphurous, Inonotus obliquus, Lentinula edodes; Lentinus lepideus, L. giganteus, L. squarrosulus and L. tigrinus, Fusarium sp., Fusarium culmorum, Fusarium solani, Aspergillus sp., Aspergillus oryzae, Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Aspergillus terreus, Trichoderma sp., Trichoderma reesei, Trichoderma viride, Trichoderma longibrachiatum, Cladosporium sp., Chaetomium sp., Chaetomium globosum.

[0056] More particularly, les enzymes sont choisies parmi le groupe forme par les proteases, les laccases, amylases, cellulases, chitinases, xylanases, manganèse peroxidases, lipases, lignine peroxidases.

[0057] In yet another advantageous embodiment according to the present invention, said biomolecules are active biomolecules such as, for example, UV filters, pigments, antioxidants, anti-radical substances, and in which said at least one fungal strain comprises at least one strain producing active biomolecules is chosen from the group of strains belonging to the genus Pycnoporus, Pleurotus, Trametes, Fusariums, Ganoderma, such as, for example, Pycnoporus sanguineus, Pleurotus citrinopileatus, Fusarium oxysporum, Fusarium graminearum, Fusarium fujikuroi, Trametes versicolor.

[0058] Examples of pigments, but not limited to, include cinnabarin, cinnabarinic acid, tramesanguine, PsPCP, carmine red anthraquinone, aurofusarin, bikaverin.

[0059] Other embodiments of the biogas production process according to the invention are indicated in the appended claims as well as in the description below, given without limitation.

[0060] The present invention relates to a method for producing biogas from fibrous substrate in which a fibrous substrate is biologically pretreated by solid fermentation using one or more fungal strains thereby forming a fibrous substrate shredded into pieces colonized by said at least one fungal strain and which is then transferred to a biogas production plant. Once transferred to the biogas production plant, the microorganisms of the biogas production plant can then digest (anaerobic digestion) the fibrous substrate colonized by said one or more fungal strains.

[0061] The digestate produced after biogas production is then collected.

[0062] According to the present invention, the fungal strain may be a strain with high colonizing power that will rapidly grow on the fibrous substrate and use it for its growth. This makes it possible to convert carbonaceous material that is difficult for methanogenic microorganisms to access into more easily accessible carbonaceous material. The fungal strain used may also be an enzyme-producing strain. In this case, simultaneously with the growth of the fungal biomass, an enzyme production is carried out which thus acts synergistically on the digestion of the fibers of the fibrous substrate. The enzymes make it possible to facilitate subsequent access to methanogenic microorganisms.

[0063] In certain embodiments according to the invention, a mixture of several strains will be chosen in order to optimize the pretreatment of the fibrous substrate by the fungal strains.

[0064] The agglomerated, woven or non-woven shredded fibrous substrate typically comprises fibers selected from natural vegetable or animal textile fibers, semi-synthetic textile fibers or polymer textile fibers, lignocellulosic fibers. It is preferably a residue from the grinding of recycled textiles, more particularly recycled furnishing textiles, recycled mattresses, bathroom or bed linen, clothing textiles, textile production scraps or waste, upholstery and mixtures thereof. It is even more preferably a residue from the grinding of recycled textiles selected from furnishing textiles, mattresses and upholstery and has a synthetic foam content of between 10 and 80%. This residue may also contain wood grinding residues.

[0065] In this particular case of upholstery fabrics, mattresses, and padding, there is currently no recovery channel, as this waste has too great a diversity of composition. Typically, the fibrous substrate includes a proportion of synthetic fibers, semi-synthetic fibers, synthetic foam, such as PU foam, and natural plant or animal fibers.

[0066] While many stakeholders see the presence of synthetic fibers or contamination by plastic foams, such as PU foam, as a disadvantage because it is typically a substrate that is not digestible by methanogenic microorganisms, the present invention provides a technological breakthrough by choosing to treat the fibrous substrate with synthetic contaminants in order to enrich the digestate with synthetic and plastic material so that it can be recovered in the plastics recycling sector. According to the present invention, the collected digestate is enriched with synthetic fibers and plastic materials at a rate of more than 85% by weight relative to the weight of digestate.

[0067] According to the present invention, the biological pretreatment step comprises:

[0068] - conditioning said fibrous substrate to obtain a conditioned fibrous substrate containing from 60 to 80% by weight of water relative to the weight of conditioned fibrous substrate, hygienization of said conditioned fibrous substrate to form a hygienized conditioned fibrous substrate, cooling of the hygienized conditioned fibrous substrate for a period of time between 12 and 24 hours, seeding of said hygienized conditioned fibrous substrate using mycelial spawn from said one or more fungal strains on seeds by adding at least one mycelial spawn on seeds to said hygienized conditioned fibrous substrate at a rate of 0.5% to 10% by weight, more particularly 1 to 7%, more particularly still 3 to 5% by weight of mycelial spawn relative to the weight of hygienized conditioned fibrous substrate, with obtaining seeded hygienized conditioned fibrous substrate,a mixture of said seeded hygienized conditioned fibrous substrate with obtaining a homogenized seeded hygienized conditioned fibrous substrate, an incubation of said homogenized seeded hygienized conditioned fibrous substrate for a period of time between 1 and 6 weeks, more particularly between 2 and 5 weeks, in an enclosure having a relative humidity between 65 and 85%, more particularly between 70 and 80%, and a collection of a fibrous substrate colonized by said one or more fungal strains forming said biologically pretreated fibrous substrate.,

[0069] This makes it possible to use fibrous substrates which are currently not used due to the complexity of accessing the carbon mass.

[0070] According to the present invention, said hygienization of the conditioned fibrous substrate is a pasteurization to obtain the conditioned fibrous substrate hygienized for a period of at least 3 hours, preferably at least 4 hours, more preferably at least 5 hours at a temperature greater than or equal to 72°C.

[0071] More particularly, in the method according to the present invention, the pasteurization is carried out at increasing temperature until a temperature peak greater than 85°C is obtained, more particularly 88°C, more particularly 90°C, maintained for a period of time of between 5 and 50 minutes, more particularly 30 and 40 min.

[0072] In a variant according to the present invention, said hygienization of the conditioned fibrous substrate is a composting comprising at least one composting cycle comprising a step of increasing the temperature until a temperature of between 55 and 80°C is obtained, more preferably until a temperature of between 58 and 65°C is obtained, for a period of time of between 6 hours and 5 days, followed by a step of aeration of said fibrous substrate to maintain a temperature of between 46 and 49° for 3 to 7 days, possibly by turning the fibrous substrate over.

[0073] Composting provides sufficient hygiene of the fibrous substrate while avoiding energy-intensive steps.

[0074] In a preferred embodiment according to the present invention, said step of conditioning said fibrous substrate to obtain a conditioned fibrous substrate comprises moistening the fibrous substrate and / or washing said fibrous substrate optionally followed by draining or drying.

[0075] In yet another preferred embodiment according to the present invention, said step of conditioning said fibrous substrate comprises an additional step of supplementing with essential elements, such as for example minerals (calcium, magnesium), phosphorus, carbon and nitrogen sources, typically to obtain a fibrous substrate whose carbon: nitrogen ratio is between 10 and 30, preferably between 15 and 20, for example by adding grains.

[0076] In another variant according to the present invention, said hygienization of the conditioned fibrous substrate comprises at least 2, 3, 4, 5, 6, 7, 8, or even 10 consecutive composting cycles.

[0077] In the method according to the present invention, it is also planned to produce biomolecules of interest during the biological pretreatment by one or more fungal strains. Indeed, waste recovery is currently only implemented on an industrial scale if it is financially profitable, whether on its energy ratio, because the raw material has a negative purchase cost (i.e. the waste producer finances the one who will treat it), or because it generates a financially recoverable material.

[0078] To encourage the recycling of textile waste, the present invention provides for the simultaneous production of high added-value biomolecules of interest which could provide an additional incentive to the operator of the biogas production unit. These biomolecules can be for industrial use (pigments, detergents, etc.) or for cosmetic, pharmaceutical or therapeutic use, depending on the conditions of the biological pretreatment.

[0079] The biomolecules that can be produced have been described above.

[0080] Alternatively, these biomolecules are preferably selected from enzymes or biomolecules with a molecular weight of less than 5000 Da, preferably less than 1000 Da, such as flavors, surfactants or colorants and / or terpene derivatives. Preferably, these biomolecules are recovered before the biologically pretreated fibrous substrate is transferred to the biogas production plant.

[0081] It is understood that the present invention is in no way limited to the embodiments described above and that many modifications may be made thereto without departing from the scope of the appended claims.

Claims

CLAIMS 1. Process for producing biogas from fibrous substrate comprising: Biological pretreatment of the fibrous substrate forming a biologically pretreated fibrous substrate Transfer of biologically pretreated fibrous substrate into a biogas production facility Production of biogas from pre-treated fibrous substrate with formation of digestate, A collection of the digestate, the method being characterized in that the biological pretreatment of the fibrous substrate is a solid fermentation using one or more filamentous fungal strains, more particularly using one or more saprophytic filamentous strains, of a woven, non-woven or agglomerated fibrous substrate, and shredded into pieces where said biologically pretreated fibrous substrate is a fibrous substrate shredded into pieces colonized by said one or more fungal strains.

2. A method for producing biogas from fibrous substrate according to claim 1, wherein said one or more fungal strains comprise at least one fungal strain with high colonizing power chosen from the group consisting of strains belonging to the genera Agrocybe, Ganoderma, Trametes, Pycnoporus, Pleurotus, Fomes, Fomitopsis, Irpex, Laetiporus, Inonotus, Lentinula, Fusarium, Aspergillus, Trichoderma, Penicillium, Cladosporium, Chaetomium, Acremonium.

3. A method for producing biogas from fibrous substrate according to claim 1 or claim 2, wherein said one or more fungal strains comprises at least one enzyme-producing fungal strain selected from the group consisting of strains belonging to the genus Agrocybe, Ganoderma, Trametes, Pycnoporus, Pleurotus, Fomes, Fomitopsis, Irpex, Laetiporus, Inonotus, Lentinula, Fusarium, Aspergillus, Trichoderma, Penicillium, Cladosporium, Chaetomium, Acremonium.

4. Method for producing biogas from fibrous substrate according to one of claims 1 to 3, in which said one or more fungal strains is a mixture of one or more strains with high colonizing power and one or more enzyme-producing strains.

5. A method of producing biogas from fibrous substrate according to any one of the preceding claims, wherein the agglomerated, woven or non-woven shredded fibrous substrate comprises fibers chosen from natural plant or animal textile fibers, semi-synthetic textile fibers or polymer textile fibers, lignocellulosic fibers.

6. A method for producing biogas from a fibrous substrate according to any one of the preceding claims, wherein the agglomerated, woven or non-woven shredded fibrous substrate is a residue from the grinding of recycled textiles, more particularly recycled furnishing textiles, recycled mattresses, bathroom or bed linen, clothing textiles, textile production scraps or waste, upholstery and mixtures thereof.

7. Process for producing biogas from a fibrous substrate according to any one of the preceding claims, in which said fibrous substrate in agglomerated, woven or non-woven form is a residue from the grinding of recycled textiles chosen from furnishing, mattress and upholstery textiles and has a synthetic foam content of between 10 and 80%.

8. Process for producing biogas from fibrous substrate according to any one of the preceding claims, in which said fibrous substrate in agglomerated, woven or non-woven form is a residue from the grinding of lignocellulosic elements, such as for example residues from the grinding of agglomerated wood.

9. A method of producing biogas from a fibrous substrate according to any one of the preceding claims, wherein said fibrous substrate comprises a proportion of synthetic fibers, semi-synthetic fibers, synthetic foam, such as for example PU foam, and natural plant or animal fibers, and wherein the collected digestate is enriched with synthetic fibers and plastic materials at a rate of more than 85% by weight relative to the weight of digestate.

10. A method of producing biogas from fibrous substrate according to any one of the preceding claims, wherein the biological pretreatment step comprises: - conditioning said fibrous substrate to obtain a conditioned fibrous substrate containing from 60 to 80% by weight of water relative to the weight of conditioned fibrous substrate, sanitizing said conditioned fibrous substrate to form a sanitized conditioned fibrous substrate, cooling the sanitized conditioned fibrous substrate for a period of time between 12 and 24 hours, seeding said sanitized conditioned fibrous substrate using mycelial spawn from said one or more fungal strains on seeds by adding at least one mycelial spawn on seeds to said sanitized conditioned fibrous substrate at a rate of 0.5% to 10% by weight, more particularly 1 to 7%, more particularly still 3 to 5% by weight of mycelial spawn relative to the weight of sanitized conditioned fibrous substrate,or seeding from a liquid culture of said one or more fungal strains with obtaining a seeded hygienized conditioned fibrous substrate, a mixture of said seeded hygienized conditioned fibrous substrate with obtaining a homogenized seeded hygienized conditioned fibrous substrate, an incubation of said homogenized seeded hygienized conditioned fibrous substrate for a period of time between 1 and 6 weeks, more particularly between 2 and 5 weeks, in an enclosure having a relative humidity between 65 and 85%, more particularly between 70 and 80%, and a collection of a fibrous substrate colonized by said one or more fungal strains forming said biologically pretreated fibrous substrate., 1 1. Process for producing biogas from fibrous substrate according to claim 10, wherein said hygienization is steam pasteurization to obtain a conditioned fibrous substrate hygienized for a period of at least 3 hours, preferably at least 4 hours, more preferably at least 5 hours at a temperature greater than or equal to 72°C.

12. Process for producing biogas from fibrous substrate according to claim 11, in which the pasteurization is carried out at increasing temperature until a temperature peak of more than 85°C is obtained, more particularly 88°C, more particularly 90°C, maintained for a period of time of between 5 and 50 minutes, more particularly 30 and 40 min.

13. A method for producing biogas from fibrous substrate according to any one of claims 10 to 12, wherein said hygienization of the conditioned fibrous substrate is composting comprising at least one composting cycle comprising a step of increasing the temperature until a temperature of between 55 and 80°C is obtained, more preferably until a temperature of between 58 and 65°C is obtained, for a period of time of between 6 hours and 5 days, followed by a step of aerating said fibrous substrate to maintain a temperature of between 46 and 49° for 3 to 7 days, optionally by turning the fibrous substrate over.

14. A method of producing biogas from fibrous substrate according to any one of claims 10 to 13, wherein said step of conditioning said fibrous substrate to obtain a conditioned fibrous substrate comprises moistening the fibrous substrate and / or washing said fibrous substrate optionally followed by draining or drying.

15. A method of producing biogas from fibrous substrate according to any one of claims 10 to 14, wherein said step of conditioning said fibrous substrate comprises an additional step of supplementing with essential elements, such as for example minerals (calcium, magnesium), phosphorus, carbon and nitrogen sources, typically to obtain a fibrous substrate whose carbon: nitrogen ratio is between 10 and 30, preferably between 15 and 20, for example by adding grains.

16. Method for producing biogas from fibrous substrate according to any one of the preceding claims, comprising simultaneously with the pretreatment a production of biomolecules, collected in parallel, said one or more fungal strains comprising at least one strain producing biomolecules.

17. A method for producing biogas from fibrous substrate according to claim 16, wherein said biomolecules are sugars or polysaccharides and wherein said at least one fungal strain comprises at least one sugar or polysaccharide producing strain selected from the group of strains of the genus Ganoderma, Trametes and Pleurotus, such as for example the strains Ganoderma lucidum.

18. A method for producing biogas from a fibrous substrate according to claim 16, wherein said biomolecules are biomolecules of therapeutic or pharmaceutical interest such as, for example, antibiotics, antimitotics, antivirals, biosorbents, surfactants and wherein said at least one fungal strain comprises at least one strain producing therapeutic biomolecules or biomolecules usable in pharmaceutical processes such as, for example, antibiotics, antimitotics, antivirals, biosorbents, surfactants chosen from the group of strains of the genera Aspergillus, Trichoderma, Penicillium, Fusarium, Pleurotus, Pycnoporus, Trametes, Ganoderma, Pleurotus.

19. A method for producing biogas from fibrous substrate according to claim 16, wherein said biomolecules are enzymes and wherein said at least one fungal strain comprises at least one enzyme-producing strain selected from the group of strains belonging to the genus Agrocybe, Ganoderma, Trametes, Pycnoporus, Pleurotus, Fomes, Fomitopsis, Irpex, Laetiporus, Inonotus, Lentinula, Fusarium, Aspergillus, Trichoderma, Penicillium, Cladosporium, Chaetomium, Acremonium.

20. A method of producing biogas from fibrous substrate according to claim 16, wherein said biomolecules are active biomolecules, such as for example UV filters, pigments, antioxidants of anti-radical substances, and wherein said at least one fungal strain comprises at least one strain producing active biomolecules is chosen from the group of strains belonging to the genus Pycnoporus, Pleurotus, Trametes, Fusarium, Ganoderma, such as for example Pycnoporus sanguineus, Pleurotus citrinopileatus, Fusarium oxyporum, Fusarium graminearum, Fusarium fujikuroi, Trametes versicolor.

21. A method of producing biogas from a fibrous substrate according to claim 16, wherein said biomolecules are surfactants.

22. A method of producing biogas from a fibrous substrate according to any one of the preceding claims, wherein the collected digestate is inactivated, more particularly heat-inactivated, and shaped, for example into bricks, modules, panels.

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