Process for mechanochemically supported enzymatic nanocellulose production and nanocellulose obtained therefrom

Abstract

In a first aspect, the invention is directed to a process for preparing nanocellulose from a polymeric material comprising cellulose fibers, the process comprising: (i) Providing pieces p1 of the polymeric material comprising cellulose fibers; (ii) Shredding the pieces p1 provided according to (i) in n shredding devices SD(i) wherein n is an integer with n≥1 and i=1...n, thereby obtaining pieces p2, which comprise cellulose fibers; (iii) Preparing an aqueous mixture comprising the pieces p2 at a temperature T1 and adjusting the temperature of the aqueous mixture comprising the pieces p2 to a temperature T2 with T2 > T1, thereby obtaining an aqueous mixture comprising the pieces p2 and having temperature T2; (iv) Introducing at least one enzyme capable of degrading cellulose (cellulase) into the aqueous mixture obtained according to (iii), thereby obtaining an aqueous mixture comprising the pieces p2 and at least one enzyme, wherein the aqueous mixture has temperature T2; (v) optionally milling the aqueous mixture obtained according to (iv) in a milling device MD(1), thereby obtaining an aqueous mixture comprising the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers; and (vi) Milling the aqueous mixture obtained according to (iv) or (v) in a stirred media mill SMM, thereby obtaining an aqueous mixture comprising the at least one enzyme and nanocellulose (at least partially degraded and / or at least partially defibrillated cellulose).

Description

[0001] 240406W001

[0002] Process for mechanochemically supported enzymatic nanocellulose production and nanocellulose obtained therefrom

[0003] In a first aspect, the invention is directed to a process for preparing nanocellulose from a polymeric material comprising cellulose fibers, the process comprising: (i) Providing pieces p1 of the polymeric material comprising cellulose fibers; (ii) Shredding the pieces p1 provided according to (i) in n shredding devices SD(i) wherein n is an integer with n>1 and i=1 ...n, thereby obtaining pieces p2, which comprise cellulose fibers; (iii) Preparing an aqueous mixture comprising the pieces p2 at a temperature T 1 and adjusting the temperature of the aqueous mixture comprising the pieces p2 to a temperature T2 with T2 > T1, thereby obtaining an aqueous mixture comprising the pieces p2 and having temperature T2; (iv) Introducing at least one enzyme capable of degrading cellulose (cellulase) into the aqueous mixture obtained according to (iii), thereby obtaining an aqueous mixture comprising the pieces p2 and at least one enzyme, wherein the aqueous mixture has temperature T2; (v) Milling the aqueous mixture obtained according to (iv) in a milling device MD(1), thereby obtaining an aqueous mixture comprising the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers; and (v) optionally milling the aqueous mixture obtained according to (v) in a stirred media mill SMM, thereby obtaining an aqueous mixture comprising the at least one enzyme and nanocellulose (at least partially degraded and / or at least partially defibrillated cellulose). A second aspect of the invention is directed to nanocellulose obtained or obtainable from the process of the first aspect of the invention. In a third aspect, the invention relates to a production unit for carrying out a process according to the first aspect of the invention. A fourth aspect relates to nanocellulose, preferably obtained or obtainable from the process of the first aspect, having in aqueous solution with a nanocellulose content in the range of 2.5 to 3.5 weight-% a viscosity of less than 10 mPa ■ s at a shear rate of 10 s1.

[0004] Recycling processes of polymeric materials such as textile are expected to change drastically in the next years in view of the more and more stringent legislation that will be applied at least in the EU. In order to fulfil the higher recycling goals, new processes such as chemical recycling of waste material, for example textile waste material, will have to be developed and applied. The enzymatic degradation of polymers has been described in the art and processes for recycling polymeric materials comprising cellulose are known, also including enzymatic and / or mechanical treatment. For example, the mechanochemically assisted degradation of textiles has been described, wherein, for example, cellulose is ground in ball mills in the presence of water and enzymes, wherein the degradation of cellulose is done with cellulase. For example, such degradation are disclosed in "Closing the cycle: Enzymatic recovery of high purity glucose and polyester from textile blends”, Resources, Conservation & Recycling 188 (2023) 106701, which describes the grinding of the textile and enzymatic hydrolysis. However, the focus of such mechanochemically assisted degradation process is often simply to break the cellulose completely down to monomers, such as glucose. On the other hand, new materials such as nanocellulose, which is kind of a new generation of nanomaterials has been receiving extensive attention from scientists and industry because of its specific chemical and physical properties. 240406W001

[0005] - 2 -

[0006] Nanocellulose (NC) is obtained or obtainable from cellulose fibers. NC comprises various forms such as microfibrilated cellulose (MFC), nanofibrillated cellulose (NFC), nanocrystalline cellulose (NCC) or nanocellulose that is made by bacteria. Generally, nanocellulose is understood as at least partially degraded and / or at least partially defibrillated cellulose.

[0007] Mechanochemically process for generation of nanocellulose are known, for example, using vertical stirred media mills. However, these processes have drawbacks as long reaction times are required, down settling of reactants and products during standstill phases occurs etc.. Furthermore, regarding enzyme support, it is common to first apply the enzymes, let the enzymes degrade the material and then to start with the mechanical disintegration process. Said approach is at least cost intensive as the enzymes degrade during prolonged operation and a large amount of enzyme is thus required.

[0008] Therefore, there was a need to provide a new process for recycling polymeric material comprising cellulose fibers, which is more efficient and cost-effective compared to existing processes.

[0009] The invention thus relates in a first aspect to a process for preparing nanocellulose from a polymeric material comprising cellulose fibers, the process comprising:

[0010] (I) Providing pieces p1 of the polymeric material comprising cellulose fibers;

[0011] (II) Shredding the pieces p1 provided according to (i) in n shredding devices SD(i) wherein n is an integer with n>1 and i=1 ...n, thereby obtaining pieces p2, which comprise cellulose fibers;

[0012] (iii) Preparing an aqueous mixture comprising the pieces p2 at a temperature T 1 and adjusting the temperature of the aqueous mixture comprising the pieces p2 to a temperature T2 with T2 > T1 , thereby obtaining an aqueous mixture comprising the pieces p2 and having temperature T2;

[0013] (iv) Introducing at least one enzyme capable of degrading cellulose (cellulase) into the aqueous mixture obtained according to (iii), thereby obtaining an aqueous mixture comprising the pieces p2 and at least one enzyme, wherein the aqueous mixture has temperature T2;

[0014] (v) Optionally milling the aqueous mixture obtained according to (iv) in a milling device MD(1), thereby obtaining an aqueous mixture comprising the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers;

[0015] (vi) Milling the aqueous mixture obtained according to (iv) or (v) in a stirred media mill SMM, thereby obtaining an aqueous mixture comprising the at least one enzyme and nanocellulose (at least partially degraded and / or at least partially defibrillated cellulose).

[0016] Applying the at least one enzyme capable of degrading cellulose first in step (iv), i.e. after shredding the pieces p1 to the pieces p2 and preparation of aqueous mixture from the pieces p2 allows to achieve much faster degradation rates. Compared to other processes, the inventive process offers the advantage that addition of harsh chemicals such as sulfuric acid (H2SO4) and / or sodium hydroxide (NaOH) can be avoided: No H2SO4 is required to remove amorphous parts of the cellulose and no NaOH is required in order to swell cellulose in order to make it easier to be 240406W001

[0017] - 3 - milled. This results in the further advantage that the final nanocellulose obtained from the inventive process does not have to be cleaned from these chemicals after the defibrillation process is finished.

[0018] A fiber is a three dimensional body with one spatial extension being substantially larger (the length “L”) than at least one other spatial extension (width "w”). A cellulose fiber comprises beta-1 , 4-glycosidically connected glucose residues as so called cellulose polymer chains, wherein a plurality of these cellulose polymer chains forms a so called microfibril. A microfibril comprises crystalline and amorphous region(s). In turn, a plurality of microfibrils are arranged to form a so called macrofibril. Further, a plurality of macrofibrils forms the cellulose fiber, which has a diameter d in the range of from 20 to 60 m.

[0019] According to step (I), pieces p1 of a polymeric material comprising cellulose fibers are provided. Preferably, the polymeric material comprising cellulose fibers is a cellulose based textile or a cellulose pulp, more preferably a cellulose pulp, more preferably a dissolving-grade pulp. A cellulose pulp is based on at least one component selected from the group consisting of plant (especially wood and / or fiber crops), waste paper, rags and mixtures of two or more thereof. Dissolving-grade pulp is a highly pure cellulose pulp with a high o-cellulose content (> 90 weight- %) and low levels of hemicellulose (< 4 weight-%). Preferably, softwood bleached pulp is used.]

[0020] Step (ii)

[0021] Shredding the pieces p1 provided according to (I) is done according to step (II) in n shredding devices SD(i). Preferably, the n shredding devices SD(i) comprise at least a first shredding device SD(1) and a second shredding device SD(2), wherein step (II) preferably comprises:

[0022] (11.1) Shredding the pieces p1 , which have a bulk density bdpiand a length lpi, provided according to (I) in the first shredding device SD(1), thereby obtaining pieces p1 -1 , which comprise cellulose fibers, wherein the pieces p1-1 have a length with lpi-i < lp-i ;

[0023] (11.2) Shredding the pieces p1 -1 obtained according to (ii-1) in the second shredding device SD(2), thereby obtaining pieces p2, which comprise cellulose fibers, wherein the pieces p2 have a bulk density bdP2 with bdP2 < bdpi.

[0024] The length of the pieces p1 and pieces p1-1 is preferably the respective Ferret diameter of these pieces. The bulk density is preferably determined according to DIN EN ISO 60 (2023-12). As will be understood, step (ii) and also steps (ii.1) and (ii.2) are both carried out in “dry mode”, i.e. the respective shredding is done without addition of water or another solvent and the pieces to be shredded are also provided in dry state (dry shredding stage(s)).

[0025] It is preferred that the n shredding devices SD(i), preferably the first shredding device SD(1) and the second shredding device SD(2), are selected from the group consisting of a shredder, a guillotine, a hammer mill, and a cutting 240406W001

[0026] - 4 - mill, wherein SD(1) is preferably a shredder, the shredder being more preferably a double-shaft shredder or a four- shaft shredder and / or SD(2) is preferably a hammer mill.

[0027] Preferably, the particles p2 have a bulk density in the range of from 10 to 40 kg / m3, more preferably in the range of from 10 to 20 kg / m3. Bulk density is determined in that a vessel with a volume of 1 m3is completely filled with (dry) particles p2 and then weighted, wherein the bulk density is the resulting weight per volume.

[0028] Steps (Hi), (iv)

[0029] According to step (iii), an aqueous mixture comprising the pieces p2 at a temperature T1 is prepared and the temperature of the aqueous mixture comprising the pieces p2 is adjusted to a temperature T2 with T2 > T1 , thereby obtaining an aqueous mixture comprising the pieces p2 and having temperature T2; and according to step (iv), at least one enzyme capable of degrading cellulose (cellulase) is introduced into the aqueous mixture obtained according to (iii), thereby obtaining an aqueous mixture comprising the pieces p2 and at least one enzyme, wherein the aqueous mixture has temperature T2.

[0030] Preferably, the aqueous mixture comprising the pieces p2 according to (iii) and / or, preferably and, the aqueous mixture comprising the pieces p2 and at least one enzyme according to (iv) comprises said pieces p2 in a concentration in the range of from 1 to 10 weight-%, preferably in the range of from 1 to 7 weight-%, preferably in the range of from 3 to 7 weight-%, more preferably in the range of from 3 to 5 weight-%, each based on the total weight of the aqueous mixture being 100 weight-% (solid content in aqueous mixture).

[0031] It is preferred that the pH value of the aqueous mixture comprising the pieces p2 is adjusted in step (iii) to be in the range of from 3 to 6, preferably in the range of from 4 to 5, more preferably in the range of from 4.2 to 4.8, preferably by addition of an aqueous solution comprising at least one buffer; and / or wherein in step (iv) together with or prior to the introduction of the at least one enzyme, the pH value of the aqueous mixtures is adjusted to be in the range of from 3 to 6, preferably in the range of from 4 to 5, more preferably in the range of from 4.2 to 4.8, preferably by addition of an aqueous solution comprising at least one buffer.

[0032] Preferably, the at least one buffer is selected acetic acid / sodium acetate buffer and / or citrate buffer (citric acid monohydrate, potassium hydroxide and water), preferably citrate buffer.

[0033] T 1 is preferably a temperature in the range of from 10 to 40°C and T2 is preferably a temperature suitable for the at least one enzyme for degrading cellulose (cellulase) with T2, with T2 > T1 . A "temperature suitable for the at least one enzyme for degrading cellulose (cellulase)” means a temperature at which the respective enzyme works at its optimum. These temperatures are known to the skilled person and can be taken for each enzyme from the manufac- 240406W001

[0034] - 5 - turers data. In some embodiments, especially when Spartec™ CEL 100 (from BASF) is used as enzyme, T1 is preferably a temperature in the range of from 10 to 40°C and T2 is preferably a temperature in the range of from 30 to 60°C, with T2 > T1.

[0035] It is preferred that step (iii) comprises:

[0036] (iii.1) Preparing an aqueous mixture comprising the pieces p2 having a viscosity .(1) at a temperature T1 and adjusting the temperature of the aqueous mixture comprising the pieces p2 to a temperature T2 with T2 > T1 ;

[0037] (111.2) Optionally incubating the aqueous mixture comprising the pieces p2 at temperature T2 for a period of time of at least 1 minute;

[0038] (111.3) Milling the aqueous mixture of step (iii.1) or of step (iii.2) for a period of time in a milling device MD(0), so that the total energy input in kWh brought into the aqueous mixture per ton of aqueous mixture is in the range of from 10 to 100 kWh / t, preferably in the range of from 40 to 80 kWh / t; thereby obtaining an aqueous mixture comprising the pieces p2 and having a viscosity .(2), with .(2) < .(1).

[0039] "Incubating” in optional step (iii.2) means that the mixture is kept without milling - said step can also be called "soaking”, i.e. the pieces p2 are allowed to soak up by the aqueous medium. Preferably.2, the viscosity .(2) is < 10000 mPas, more preferably the viscosity .(2) is in the range of from 300 to 10000 mPas. Viscosity is, for example, measured with a HAAKE™ Viscotester™ 3 Rotational Viscometer. The milling device MD(0) is preferably a mill with rotor stator geometry or a stirred media mil, more preferably, MD(0) is a same milling device as MD(1) described herein in more detail below.

[0040] Step (iv)

[0041] According to step (iv), at least one enzyme capable of degrading cellulose (cellulase) is introduced into the aqueous mixture obtained according to (iii), thereby obtaining an aqueous mixture comprising the pieces p2 and at least one enzyme, wherein the aqueous mixture has temperature T2. Preferably, the enzyme capable of degrading cellulose introduced in step (iv) is a cellulase, preferably selected from the group consisting of beta-glucosidase, endo-1 ,4- beta-D-glucanase, exo-1 ,4-beta-D-glucanase and mixtures of two or more of these enzymes. More preferably the enzyme is selected from the group consisting of Ctec2 (Novoensis Corp), Ctec3 (from Novoensis Corp), Spartec™ CEL 100 (from BASF) and mixtures of two or more thereof. Preferably the enzyme, preferably the cellulase, has an activity in the range of from 1 to 100 FPU / g, more preferably in the range of from 4 to 10 FPU / g. The concentration refers to the solids content of cellulose in the suspension. In some preferred embodiments, the enzyme comprises or is at least Spartec™ CEL 100 (from BASF), wherein SpartecTM CEL 100 has a density in the range of from 1.05 to 1.1 g / mL and a pH in the range of from 4.2 to 4.5. Preferably, the aqueous mixture obtained according to (iv) has a viscosity .(3), which is < pi(2) and which is preferably in the range of from 0.033 x .(1) < .(3) < 0.25 x .(1). .(3) is < 1000 mPas, more preferably the viscosity .(3) is in the range of from 100 to 500 mPas. Viscosity is, for example, measured with a HAAKE™ Viscotester™ 3 Rotational Viscometer. 240406W001

[0042] - 6 -

[0043] Preferably, the enzyme is introduced in step (iv) so that in the range of from 1 to 100 FPU / g, preferably in the range of from 4 to 10 FPU / g, are finally present, wherein “g” refers to gram of dry pieces p2.

[0044] Step (v)

[0045] According to optional step (v), the aqueous mixture obtained according to (iv) is milled in a milling device MD(1 ), thereby obtaining an aqueous mixture comprising the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers. The milling device MD(1) is preferably a mill with rotor stator geometry or a stirred media mill. More preferably, the milling device MD(1) is a mill with rotor stator geometry, preferably colloid mill or refiner, having a grinding gap with a, preferably adjustable, width in the range of from 100 to 700 m, preferably in the range of from 100 to 400 pm.

[0046] Preferably, the grinding gap width is changed during step (v), wherein the grinding gap width ggw(1) at the beginning of step (v) is preferably in the range of from 100 to 700 pm, more preferably in the range of from 100 to 400 pm, and the width of the grinding gap is preferably changed during step (v) to ggw(12), wherein ggw(2) is preferably in the range of from100 to 700 pm, more preferably in the range of from 100 to 400 pm, with ggw(2)< ggw(1). For example, the width of the grinding gap at the beginning of step (v) is adjusted to be 350 pm (ggw(0)) and is then reduced over step (v) to ggw(0), which is in the range of from 100 to 200 pm.

[0047] More preferably, the milling device MD(1) is a stirred media mill SMM(MD(1)), which preferably comprises a dynamic gap separation system with a dynamic gap opening in the range of from 0.5 to 2 mm, preferably in the range of from 0.8 to 1.5 mm, more preferably in the range of from 0.9 to 1.1 mm. Preferably, the stirred media mill SMM(MD(1)) comprises milling beads having a diameter in the range of from 1 to 7 mm, preferably in the range of from 3 to 5 mm. The milling beads preferably consist of a material selected from the group consisting of ceramic; metal, preferably stainless steel; thermoset, preferably a thermoset polyurethane; and mixtures of two or more of these materials, wherein the milling beads more preferably consist of zirkonoxide-ceramic milling beads stabilised with yttrium and / or with cerium.

[0048] Preferably, the stirred media mill SMM(MD(1)) comprises a stationary vessel and a rotor configured to rotate within the vessel, wherein the rotor comprises a plurality of, preferably at least 4, more preferably at least 10, more preferably at least 20, propelling means configured for, when rotating the rotor, propelling the milling beads and the aqueous mixture to move within the vessel. Preferably, the dynamic gap separation system is arranged within the rotor, preferably the dynamic gap separation system is part of the rotor. Preferably, the propelling means are disks or finger-like structures extending radially outward from the rotor towards an inner surface of the vessel and having a diameter and / or maximum cross-sectional width in the range of from 5 to 30 mm, preferably in the range of from 10 to 25 mm. Preferably, the propelling means have a shape selected from the group consisting of a cylindrical shape, preferably the shape of a cylinder; a rectangular shape, preferably with its longer side extending outward from the rotor; a cone shape, preferably a truncated cone shape, more preferably with the cone's base being arranged closer to the rotor's 240406W001

[0049] - 7 - surface than the cone's narrower end; a polyhedron shape, preferably a pyramid shape, more preferably a truncated polyhedron, more preferably with the polyhedron's polygonal base being arranged closer to the rotor's surface than it's narrower end. Preferably, the vessel on its inside, preferably on its side facing the rotor, comprises a plurality of, preferably at least 4, more preferably at least 10, more preferably at least 20, redirecting means configured for, when rotating the rotor within the vessel, redirecting the movement of the milling beads within the vessel. Preferably, the redirecting means are finger-like structures extending radially inward from the vessel and having a diameter and / or maximum cross-sectional width in the range of from 5 to 30 mm, preferably in the range of from 10 to 25 mm. Preferably, the redirecting means have a shape selected from the group consisting of a cylindrical shape, preferably the shape of a cylinder; a rectangular shape, preferably with its longer side extending inward from the vessel; a cone shape, preferably a truncated cone shape, more preferably with the cone's base being arranged closer to the vessel's surface than the cone's narrower end; a polyhedron shape, preferably a pyramid shape, more preferably a truncated polyhedron, more preferably with the polyhedron's polygonal base being arranged closer to the vessel's surface than it's narrower end. Preferably, the rotor rotates within the vessel at a circumferential speed cs1 in the range of from 5 to 50 m / s, preferably in the range of from 8 to 14 m / s. Preferably, the stirred media mill SMM(MD(1)) has an active milling chamber volume in the range of from 5 to 150 Liters, preferably in the range of from 5 to 100 Liters, more preferably of 60 Liters. The active milling chamber volume of the stirred media mill SMM(MD(1)) is the volume of the empty vessel without rotor and without milling beads. A MacroMedia wet mill from company Buhler is preferred as stirred media mill SMM(MD(1)).

[0050] Preferably, the milling device MD(1) or the stirred media mill SMM(MD(1) is horizontally aligned and the aqueous mixture is moved in MD(1) or SMM in horizontal direction.

[0051] According to step (v), an aqueous mixture is obtained, which comprises the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers.

[0052] Step (vi)

[0053] According to step (vi), the aqueous mixture obtained according to (iv) or (v) is milled in a stirred media mill SMM, thereby obtaining an aqueous mixture comprising the at least one enzyme and nanocellulose (at least partially degraded and / or at least partially defibrillated cellulose).

[0054] Preferably, the stirred media mill SMM comprises milling beads having a diameter in the range of from 100 pm to 3 mm, preferably in the range of from 300 pm to 800 pm. The milling beads preferably consist of a material selected from the group consisting of ceramic; metal, preferably stainless steel; thermoset, preferably a thermoset polyurethane; wherein the milling beads more preferably consist of zirkonoxide-ceramic milling beads stabilised with yttrium and / or with cerium. Preferably, SMM comprises a stationary vessel and a rotor configured to rotate within the vessel, wherein the rotor comprises a plurality of, preferably at least 9, more preferably at least 18, more preferably at least 60, propelling means configured for, when rotating the rotor, propelling the milling beads and the aqueous mixture to 240406W001

[0055] - 8 - move within the vessel. The propelling means are preferably disks or finger-like structures extending radially outward from the rotor towards an inner surface of the vessel. Preferably, the propelling means have a shape selected from the group consisting of a cylindrical shape, preferably the shape of a cylinder.

[0056] It is preferred that the vessel on its inside, preferably on its side facing the rotor, comprises a plurality of, preferably at least 9, more preferably at least 18, more preferably at least 60, redirecting means configured for, when rotating the rotor within the vessel, redirecting the movement of the milling beads within the vessel. The redirecting means are preferably finger-like structures extending radially inward from the vessel. The redirecting means preferably have a cylindrical shape, more preferably the shape of a cylinder.

[0057] Preferably, the vessel on its inner surface comprises a liner, wherein the liner comprises, preferably consists of, a material selected from the group consisting of ceramic; metal, preferably Silicone Carbide SIC, stainless steel; thermoset, preferably thermoset Polyurethane; and mixtures of two or more of these materials, wherein the material preferably at least comprises Silicone Carbide SIC. The rotor preferably rotates within the vessel at a circumferential speed cs1 in the range of from5 to 50 m / s, preferably in the range of from 8 to 14 m / s. SMM has preferably an active milling chamber volume in the range of from 2 to 200 Liters, preferably in the range of from 60 to 150 Liters, more preferably of 60 Liters. The active milling chamber volume of SMM is the volume of the empty vessel without rotor and without milling beads. SMM is preferably a High performance stirred media mill (HPM) mill from any one of the companies Buhler, Bachofen or Netzsch, more preferably a Netzsch LMZ type mill with SIC liner.

[0058] Preferably, the stirred media mill SMM is horizontally aligned and the aqueous mixture is moved in SMM in horizontal direction.

[0059] It is preferred that at least in one step of (iv), (v) and (vi), more preferably in each step (iv), (v) and (vi), the temperature of the respective aqueous mixture is maintained at T2.

[0060] It is also preferred that at least in one step of (iv), (v) and (iv), more preferably in each step (iv), (v) and (vi), the pH value is adjusted or maintained in the range of from 4.0 to 6.0, preferably in the range of from 4.5 to 5.5.

[0061] Solid / liquid separation

[0062] According to step (v) and / or step (vi), an aqueous mixture is obtained. It is preferred that the aqueous mixture obtained in (v) and / or, preferably and, the aqueous mixture obtained in (vi) comprises glucose (monomer).

[0063] The inventive process preferably further comprises separation of solid and liquid parts of the aqueous mixture obtained in (v) or in (vi), preferably by gravitational forces, more preferably by centrifugation, thereby obtaining a separated solid part comprising the at least partially degraded and / or at least partially defibrillated cellulose, and a sepa- 240406W001

[0064] - 9 - rated liquid part comprising dissolved glucose (monomer) and at least a part of the at least one enzyme; and optionally removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme, from the solid part.

[0065] Preferably, the process further comprises after (iv) or after (v) and before (vi)

[0066] (x-1) Increasing the solid content of the aqueous mixture obtained in (iv) or in (v), which comprises the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers, preferably by at least 1 weight-%, based on the total weight of the aqueous mixture being 100 weight-%, wherein increasing the solid content is preferably done by centrifugation; thereby obtaining an aqueous mixture with an increased solid content, said aqueous mixture with an increased solid content comprising at least a part of the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers, wherein said aqueous mixture with an increased solid content is then subjected to the milling step according to (vi); and obtaining a separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme;

[0067] (x-2) Optionally removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme.

[0068] Increasing the solid content allows to make the milling step (vi) more efficient. Preferably, increasing the solid content is also called "dewatering”, wherein the dewatering is preferably adjusted so that the solids concentration in the aqueous mixture used in the milling step (vi) is raised to in the range of from 8 to 12 weight%, based on the total weight of the aqueous mixture with an increased solid content and comprising at least a part of the at least one enzyme and milled pieces p3 being 100 weight-%.

[0069] Preferably, the process further comprises after (vi)

[0070] (y-1) Increasing the solid content of the aqueous mixture obtained in (vi), which comprises the at least one enzyme and at least partially degraded and / or at least partially defibrillated cellulose, preferably by at least 1 weight-%, based on the total weight of the aqueous mixture being 100 weight-%, wherein increasing the solid content is preferably done by centrifugation; thereby obtaining an aqueous mixture with an increased solid content, said aqueous mixture with an increased solid content comprising the at least one enzyme and at least partially degraded and / or at least partially defibrillated cellulose, and a separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme;

[0071] (y-2) removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme, thereby obtaining the aqueous mixture with an increased solid content in separated form

[0072] (y-3) mixing the aqueous mixture with an increased solid content obtained in (y-2) with water and optionally with a stabilization agent, thereby obtaining an aqueous mixture with a re-decreased solid content;

[0073] (y-4) repeating step (y-1) based on the aqueous mixture with a re-decreased solid content obtained in (y-3), thereby obtaining: 240406W001

[0074] - 10 - an aqueous mixture with an increased solid content, said aqueous mixture with an increased solid content comprising which comprises the at least one enzyme and at least partially degraded and / or at least partially defibrillated cellulose, and a separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme;

[0075] (y-5) optionally removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme.

[0076] Stabilizing agents are known to the skilled person and comprise, for example, sodium benzoate.

[0077] Recycling of liquid fraction(s)

[0078] It is preferred that the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme and / or, preferably and, the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme is / are recycled into step (iv). Recirculating at least a part of the separated liquid part is advantageous as also a part of the enzyme is thus recycled to step (iv). The enzyme costs account for a considerable part of the overall processing costs. Therefore, an enzymatic recycling is advantageous at least in view of economic reasons.

[0079] 2ndaspect - degraded and / or defibrillated cellulose

[0080] A second aspect of the invention is directed to nanocellulose (at least partially degraded and / or at least partially defibrillated cellulose) obtained or obtainable from the process of the first aspect of the invention as described herein above. All details, embodiments and preferred embodiments described above with respect to the process of the first aspect of the invention apply also to the second aspect of the invention.

[0081] 3rdaspect - Recycling unit

[0082] In a third aspect, the invention is related to a production unit for carrying out a process according to the first aspect of the invention, the production unit comprising a first shredding device SD(1) and a second shredding device SD(2), wherein SD(1) and SD(2) each have inlet means for introduction of solids, preferably dry solids, more preferably solid dry pieces p1 of a polymeric material comprising cellulose fibers and outlet means for removing shredded dry solid material; a heat adjustable vessel having inlet means for introducing shredded dry solid material, for introducing enzymes, and for introducing water; and having outlet means for removing an aqueous mixture; a milling device MD(1) having inlet means and outlet means, wherein at least one inlet means of the milling device MD(1) is preferably connectable or connected with at least one outlet means of the heat adjustable vessel by means for passing an aqueous mixture from the heat adjustable vessel to the milling device MD(1); 240406W001

[0083] - 11 - a stirred media mill SMM having inlet means, wherein at least one inlet means of the stirred media mill SMM is connectable or connected with an outlet means of the milling device MD(1) by means for passing an aqueous mixture from the milling device MD(1) to the stirred media mill SMM, the stirred media mill SMM having at least one outlet means for removing an aqueous mixture.

[0084] The production unit preferably further comprises at least one solid liquid separation unit SLSU, more preferably located in between the milling device MD(1) and the stirred media mill SMM and / or located downstream of the stirred media mill SMM, the at least one solid liquid separation unit SLSU having at least one inlet means connected with at least one outlet means of the milling device

[0085] MD(1) and / or at least one inlet means preferably being connected with at least one outlet means of the stirred medial mill SMM by means for passing an aqueous mixture,

[0086] SLSU further having at least one outlet means for removing a liquid fraction, said at least one outlet means preferably being connectable or connected by at least one means for passing liquids with at least one inlet means of the milling device MD(1), for transferring a liquid fraction from the solid separation unit SLSU to the milling device MD(1).

[0087] The production unit preferably comprises at least one solid liquid separation unit SLSU located in between the milling device MD(1) and the stirred media mill SMM, the at least one solid liquid separation unit SLSU having at least one inlet means preferably being connected by at least one means for passing liquids with at least one outlet means of the milling device MD(1 ), SLSU further having at least one outlet means for removing a liquid fraction, said at least one outlet means preferably being connected by at least one means for passing liquids with at least one inlet means of the milling device MD (1 ), for transferring a liquid fraction from the solid separation unit SLSU to the milling device MD(1).

[0088] Preferably, the at least one solid liquid separation unit SLSU comprises at least one inlet mean for introducing water.

[0089] The production unit preferably comprises at least one solid liquid separation unit SLSU located downstream of the stirred media mill SMM, the at least one solid liquid separation unit SLSU having at least one inlet means preferably being connected by at least one means for passing liquids with at least one outlet means of the stirred media mill SMM, SLSU further preferably having at least one outlet means for removing a liquid fraction, said at least one outlet means preferably being connected by at least one means for passing liquids with at least one inlet means of the milling device MD(1 ), for transferring a liquid fraction from the solid separation unit SLSU to the milling device MD(1).

[0090] 4th - Nanocellulose

[0091] Viscosity 240406W001

[0092] - 12 -

[0093] A fourth aspect of the invention relates to nanocellulose, preferably obtained or obtainable from the process the first aspect as described herein above, having in aqueous solution with a nanocellulose content in the range of 2.5 to 3.5 weight-% a viscosity of less than 10 mPa ■ s at a shear rate of 10 s1, preferably determined according to the method described herein above under M.1.

[0094] All details, embodiments and preferred embodiments described above with respect to the process of the first aspect of the invention apply also to the second aspect of the invention. Here and in the following: The terms "nanocellulose” as well as "inventive nanocellulose” preferably mean a nanocellulose obtained or obtainable from the process the first aspect as described herein above, and commercially available nanocellulose means, for example, nanocellulose of company Sappi Valida (CAS no. 9004-34-6) or nanocellulose from company Borregaard called Exilva (CAS no. 9004-34-6) or bacterial produced nanocellulose such as Cellulon of company CP Kelco.

[0095] Preferably, the nanocellulose has in aqueous solution with a nanocellulose content in the range of 2.5 to 3.5 weight- % a viscosity of less than 5 mPa ■ s at a shear rate of 10 s1, preferably determined according to the method described herein above under M.1.

[0096] Preferably, an aqueous mixture of said nanocellulose having a solid content in the range of from 0.1 to 10 weight-%, more preferably in the range of from 0.5 to 6 weight-%, is shear thinning (flow index < 1). It has to be noted that normal, commercially available nanocellulose is shear thickening (flow index > 1).

[0097] Furthermore, a commercially available nanocellulose has to be diluted in aqueous mixture to a solid content (SC) about 0.8 weight-% before it can be coated via spray drying. A higher solid content is impossible as clogging of the nozzle occurs and / or the material cannot be sucked in. Due to the dilution, a larger amount of aqueous mixture has to be used in order to achieve a sufficient amount of solid on a substrate. Contrary thereto, the inventive nanocellulose can be spray coated at higher solid content in aqueous solution in the range of 2.5 to 3.5 weight-%, so that significantly less of said aqueous mixture is required for achieving a sufficient amount of solid on a substrate. Furthermore, using the inventive nanocellulose in aqueous solution in the range of 2.5 to 3.5 weight-% offers the advantage that in coating such as spray drying substantially less water has to be removed in order to get a dry coating layer on a substrate, which in turn is favorable with respect to energy consumption for drying and also with respect to drying time. This also offers the advantage that the substrate as well as the nanocellulose has to endure drying conditions (such as high temperature > 300°C) for a substantially shorter period of time, which in turn is beneficial as the material does not decompose or at least decomposes to a smaller degree, especially if a spray piston having a nozzle diameter in the range of form 1 to 2 mm and / or, preferably and, an operating pressure in the range of from 1 to 3 bar is used.

[0098] The nanocellulose is preferably obtained or obtainable from the process the first aspect as described herein above, with a total energy input of in the range of from 100 to 800 kWh / t, preferably in the range of from 128 to 556 kWh, 240406W001

[0099] - 13 - brought into the aqueous mixture per ton of aqueous mixture over said process, more preferably in the range of from 50 to 300 kWh brought into the aqueous mixture per ton of aqueous mixture over said process.

[0100] Yield point

[0101] Preferably, an aqueous mixture of said nanocellulose preferably having a solid content in the range of from 0.1 to 10 weight-%, more preferably in the range of from 0.5 to 6 weight-%, more preferably in the range of from 1 to 2 weight- %, has a yield point of less than 10 Pa, preferably of less than 5 Pa, more preferably of less than 2 Pa, preferably determined according to the method described herein below under M.2.

[0102] Compared to commercially available nanocellulose, which has a much higher yield point, the yield point of the inventive nanocellulose is less than 10 Pa.

[0103] Thermogravimetric properties

[0104] Preferably, the nanocellulose has a weight loss in thermogravimetric analysis (TGA) according to DIN 51006:2024 DE starts at 220°C and / or, wherein Tf (inflection point of the curve in the TGA diagram) is at about 305 °C, preferably for nanocellulose obtained from a total energy input of in the range of from 100 to 800 kWh / t, preferably in the range of from 128 to 556 kWh, brought into the aqueous mixture per ton of aqueous mixture.

[0105] Barrier properties

[0106] Preferably, the nanocellulose has an air flow resistance of < 100 ml / min, more preferably of < 50 ml / min, preferably of < 10 ml / min, determined according to Bendtsen (ISO 5636-3:2013), preferably for a dry coating thereof on paper having a weight of in the range of from 1 to 10 g / m2, preferably in the range of from 3 to 9 g / m2, more preferably of 4 to 8 g / m2. Advantageously, the inventive nanocellulose allows for an almost complete barrier against air permeation, whereas the comparative nanocellulose was only slightly better with respect to air flow resistance than the uncoated paper. This also has the advantage that good barrier properties can be achieved with little amounts of nanocellulose to be applied and that energy consumption with respect to drying of a coating, period of time for drying of a coating and thus in turn also decomposition can be kept at minimum when the inventive nanocellulose is used. The barrier properties indicated herein apply especially for unbleached Kraftliner paper as paper substrate, especially when the testing papers were stored for 24 h at 50% rel. humidity at 22°C after coating and before determination of the barrier properties.

[0107] Crystallinity 240406W001

[0108] - 14 -

[0109] Preferably, the nanocellulose has a crystallinity determined according to ISO / TS 23361 in the range of from 70 to 80 %. Thus, the inventive nanocellulose is as good as commercially available nanocellulose, which also has a crystallinity determined according to ISO / TS 23361 in the range of from 70 to 80 %.

[0110] It was further found that with further energy intake the crystallinity can be further reduced down to 50% or lower. This points to amorphization of the inventive nanocellulose. Such an amorphization is quite favorable when it comes to improving solubility and also swelling, which is in turn favorable for several applications.

[0111] The inventive nanocellulose as described herein above can be used for varying purposes, for example, it is advantageous when used for coatings, as due to the higher solid content in aqueous mixture, more concentrated aqueous mixtures can be used and consequently, less energy is required for drying, i.e. for water removal and also less water has to be removed for obtaining a dry coating, which is advantageous at least in view of ecological aspects.

[0112] The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The process of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The process of any one of embodiments 1, 2, 3 and 4". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.

[0113] 1 . A process for preparing nanocellulose from a polymeric material comprising cellulose fibers, the process comprising:

[0114] (i) Providing pieces p1 of the polymeric material comprising cellulose fibers;

[0115] (ii) Shredding the pieces p1 provided according to (i) in n shredding devices SD(i) wherein n is an integer with n>1 and i=1 ...n, thereby obtaining pieces p2, which comprise cellulose fibers;

[0116] (iii) Preparing an aqueous mixture comprising the pieces p2 at a temperature T 1 and adjusting the temperature of the aqueous mixture comprising the pieces p2 to a temperature T2 with T2 > T1 , thereby obtaining an aqueous mixture comprising the pieces p2 and having temperature T2;

[0117] (iv) Introducing at least one enzyme capable of degrading cellulose (cellulase) into the aqueous mixture obtained according to (iii), thereby obtaining an aqueous mixture comprising the pieces p2 and at least one enzyme, wherein the aqueous mixture has temperature T2;

[0118] (v) Optionally milling the aqueous mixture obtained according to (iv) in a milling device MD(1), thereby obtaining an aqueous mixture comprising the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers;

[0119] (vi) Milling the aqueous mixture obtained according to (iv) or (v) in a stirred media mill SMM, thereby obtaining an aqueous mixture comprising the at least one enzyme and nanocellulose (at least partially degraded and / or at least partially defibrillated cellulose). 240406W001

[0120] - 15 -

[0121] 2. The process of embodiment 1 , wherein the polymeric material comprising cellulose fibers is a cellulose based textile or a cellulose pulp, more preferably a cellulose pulp, more preferably a dissolving-grade pulp.

[0122] 3. The process of embodiment 1 or 2, wherein the n shredding devices SD(i) comprise at least a first shredding device SD(1) and a second shredding device SD(2), wherein

[0123] (ii) preferably comprises:

[0124] (ii.1) Shredding the pieces p1, which have a bulk density bdpiand a length lpi, provided according to (I) in the first shredding device SD(1), thereby obtaining pieces p1-1, which comprise cellulose fibers, wherein the pieces p1 -1 have a length with lpi-i < lp-i ;

[0125] (ii.2) Shredding the pieces p1 -1 obtained according to (ii-1) in the second shredding device SD(2), thereby obtaining pieces p2, which comprise cellulose fibers, wherein the pieces p2 have a bulk density bdP2 with bdP2 < bdpi.

[0126] 4. The process of any one of embodiments 1 to 3, wherein the n shredding devices SD(i), preferably the first shredding device SD(1) and the second shredding device SD(2), are selected from the group consisting of a shredder, a guillotine, a hammer mill, and a cutting mill, wherein SD(1) is preferably a shredder, the shredder being more preferably a double-shaft shredder or a four-shaft shredder and / or SD(2) is preferably a hammer mill.

[0127] 5. The process of any one of embodiments 1 to 5, wherein the particles p2 have a bulk density in the range of from 10 to 40 kg / m3, preferably in the range of from 10 to 20 kg / m3.

[0128] 6. The process of any one of embodiments 1 to 5, wherein the aqueous mixture comprising the pieces p2 according to (ill) and / or, preferably and, the aqueous mixture comprising the pieces p2 and at least one enzyme according to (iv) comprises said pieces p2 in a concentration in the range of from 1 to 10 weight-%, preferably in the range of from 1 to 7 weight-%, preferably in the range of from 3 to 7 weight-%, more preferably in the range of from 3 to 5 weight-%, each based on the total weight of the aqueous mixture being 100 weight-% (solid content in aqueous mixture).

[0129] 7. The process of any one of embodiments 1 to 6, wherein the pH value of the aqueous mixture comprising the pieces p2 is adjusted in step (ill) to be in the range of from 3 to 6, preferably in the range of from 4 to 5, more preferably in the range of from 4.2 to 4.8, preferably by addition of an aqueous solution comprising at least one buffer; and / or wherein in step (iv) together with or prior to the introduction of the at least one enzyme, the pH value of the aqueous mixtures is adjusted to be in the range of from 3 to 6, preferably in the range of from 4 to 5, more preferably in the range of from 4.2 to 4.8, preferably by addition of an aqueous solution comprising at least one buffer. 240406W001

[0130] - 16 -

[0131] 8. The process of embodiment 7, wherein the at least one buffer is selected acetic acid / sodium acetate buffer and / or citrate buffer (citric acid monohydrate, potassium hydroxide and water), preferably citrate buffer.

[0132] 9. The process of any one of embodiments 1 to 8, wherein T1 is a temperature in the range of from 10 to 40°C and T2 is a temperature suitable for the at least one enzyme for degrading cellulose (cellulase) with T2, with T2 > T1.

[0133] 10. The process of any one of embodiments 1 to 9, wherein step (ill) comprises:

[0134] (ill.1) Preparing an aqueous mixture comprising the pieces p2 having a viscosity .(1) at a temperature T1 and adjusting the temperature of the aqueous mixture comprising the pieces p2 to a temperature T2 with T2 > T1;

[0135] (111.2) Optionally incubating the aqueous mixture comprising the pieces p2 at temperature T2 for a period of time of at least 1 minute;

[0136] (111.3) Milling the aqueous mixture of step (ill.1 ) or of step (ill.2) for a period of time in a milling device MD(0), so that the total energy input in kWh brought into the aqueous mixture per ton of aqueous mixture is in the range of from 10 to 100 kWh / t, preferably in the range of from 40 to 80 kWh / t; thereby obtaining an aqueous mixture comprising the pieces p2 and having a viscosity .(2), with .(2) < .(1).

[0137] 11. The process of any one of embodiments 1 to 10, wherein the enzyme capable of degrading cellulose introduced in step (iv) is a cellulase, preferably selected from the group consisting of beta-glucosidase, endo-1,4- beta-D-glucanase, exo-1,4-beta-D-glucanase and mixtures of two or more of these enzymes.

[0138] 12. The process of any one of embodiments 1 to 9, wherein the enzyme is introduced in step (iv) so that in the range of from 1 to 100 FPU / g, preferably in the range of from 4 to 10 FPU / g, are finally present, wherein “g” refers to gram of dry pieces p2.

[0139] 13. The process of any one of embodiments 1 to 12, wherein the milling device MD(1) is a mill with rotor stator geometry or a stirred media mil.

[0140] 14. The process of embodiment 13, wherein the milling device MD(1) is a mill with rotor stator geometry, preferably colloid mill or refiner, having a grinding gap with a, preferably adjustable, width in the range of from 100 to 700 pm, preferably in the range of from 100 to 400 pm.

[0141] 15. The process of embodiment 14, wherein the grinding gap width is changed during step (v), wherein the grinding gap width ggw(1) at the beginning of step (v) is in the range of from 100 to 700 pm, preferably in the range of from 100 to 400 pm, and the width of the grinding gap is changed during step (v) to ggw(12), wherein 240406W001

[0142] - 17 - ggw(2) is in the range of fromlOO to 700 m, preferably in the range of from 100 to 400 pm, with ggw(2)< ggw(i).

[0143] 16. The process of embodiment 13, wherein the milling device MD(1) is a stirred media mill SMM(MD(1)), which preferably comprises a dynamic gap separation system with a dynamic gap opening in the range of from 0.5 to 2 mm, preferably in the range of from 0.8 to 1.5 mm, more preferably in the range of from 0.9 to 1.1 mm.

[0144] 17. The process of embodiment 16, wherein the stirred media mill SMM(MD(1)) comprises milling beads having a diameter in the range of from 1 to 7 mm, preferably in the range of from 3 to 5 mm.

[0145] 18. The process of embodiment 16 or 17, wherein the milling beads preferably consist of a material selected from the group consisting of ceramic; metal, preferably stainless steel; thermoset, preferably a thermoset polyurethane; and mixtures of two or more of these materials, wherein the milling beads more preferably consist of zirkonoxide-ceramic milling beads stabilised with yttrium and / or with cerium.

[0146] 19. The process of any one of embodiments 1 to 18, wherein the milled pieces p3 comprise at least partially degraded cellulose fibers.

[0147] 20. The process of any one of embodiments 1 to 19, wherein the stirred media mill SMM comprises milling beads having a diameter in the range of from 100 pm to 3 mm, preferably in the range of from 300 pm to 800pm.

[0148] 21 . The process of embodiment 20, wherein the milling beads preferably consist of a material selected from the group consisting of ceramic; metal, preferably stainless steel; thermoset, preferably a thermoset polyurethane; wherein the milling beads more preferably consist of zirkonoxide-ceramic milling beads stabilised with yttrium and / or with cerium.

[0149] 22. The process of any one of embodiments 20 or 21, wherein SMM comprises a stationary vessel and a rotor configured to rotate within the vessel, wherein the rotor comprises a plurality of, preferably at least 9, more preferably at least 18, more preferably at least 60, propelling means configured for, when rotating the rotor, propelling the milling beads and the aqueous mixture to move within the vessel.

[0150] 23. The process of embodiment 22, wherein the propelling means are disks or finger-like structures extending radially outward from the rotor towards an inner surface of the vessel.

[0151] 24. The process of any one of embodiments 22 or 23, wherein the propelling means have a shape selected from the group consisting of a cylindrical shape, preferably the shape of a cylinder. 240406W001

[0152] - 18 -

[0153] 25. The process of any one of embodiments 22 to 24, wherein the vessel on its inside, preferably on its side facing the rotor, comprises a plurality of, preferably at least 9, more preferably at least 18, more preferably at least 60, redirecting means configured for, when rotating the rotor within the vessel, redirecting the movement of the milling beads within the vessel.

[0154] 26. The process of embodiment 25, wherein the redirecting means are finger-like structures extending radially inward from the vessel.

[0155] 27. The process of any one of embodiments 25 or 26, wherein the redirecting means have a cylindrical shape, preferably the shape of a cylinder.

[0156] 28. The process of any one of embodiments 22 to 27, wherein the vessel on its inner surface comprises a liner, wherein the liner comprises, preferably consists of, a material selected from the group consisting of ceramic; metal, preferably Silicone Carbide SIC, stainless steel; thermoset, preferably thermoset Polyurethane; ;and mixtures of two or more of these materials, wherein the material preferably at least comprises Silicone Carbide SIC.

[0157] 29. The process of any one of embodiments 22 to 28, wherein the rotor rotates within the vessel at a circumferential speed cs1 in the range of from 5 to 50 m / s, preferably in the range of from 8 to 14 m / s.

[0158] 30. The process of any one of embodiments 22 to 29, wherein SMM has an active milling chamber volume in the range of from 2 to 200 Liters, preferably in the range of from 60 to 150 Liters, more preferably of 60 Liters.

[0159] 31 . The process of any one of embodiments 1 to 30, wherein at least in one step of (iv), (v) and (vi), preferably in each step (iv), (v) and (vi), the temperature of the respective aqueous mixture is maintained at T2.

[0160] 32. The process of any one of embodiments 1 to 31 , wherein at least in one step of (iv), (v) and (vi), preferably in each step (iv), (v) and (vi), the pH value is adjusted or maintained in the range of from 4.0 to 6.0, preferably in the range of from 4.5 to 5.5.

[0161] 33. The process of any one of embodiments 1 to 32, wherein the aqueous mixture obtained in (v) and / or, preferably and, the aqueous mixture obtained in (vi) comprises glucose (monomer).

[0162] 34. The process of any one of embodiments 1 to 33, further comprising

[0163] Separation of solid and liquid parts of the aqueous mixture obtained in (v) or in (vi), preferably by gravitational forces, more preferably by centrifugation, thereby obtaining a separated solid part comprising the at least partially degraded and / or at least partially defibrillated cellulose, and a separated liquid part comprising dissolved glucose (monomer) and at least a part of the at least one enzyme; 240406W001

[0164] - 19 - optionally removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme, from the solid part.

[0165] 35. The process of any one of embodiments 1 to 34, further comprising after (iv) or after (v) and before (vi) (x-1) Increasing the solid content of the aqueous mixture obtained in (iv) or in (v), which comprises the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers, preferably by at least 1 weight-%, based on the total weight of the aqueous mixture being 100 weight- %, wherein increasing the solid content is preferably done by centrifugation; thereby obtaining an aqueous mixture with an increased solid content, said aqueous mixture with an increased solid content comprising at least a part of the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers, wherein said aqueous mixture with an increased solid content is then subjected to the milling step according to (vi); and obtaining a separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme;

[0166] (x-2) Optionally removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme.

[0167] 36. The process of any one of embodiments 1 to 34 or 35, further comprising after (vi)

[0168] (y-1) Increasing the solid content of the aqueous mixture obtained in (vi), which comprises the at least one enzyme and at least partially degraded and / or at least partially defibrillated cellulose, preferably by at least 1 weight-%, based on the total weight of the aqueous mixture being 100 weight-%, wherein increasing the solid content is preferably done by centrifugation; thereby obtaining an aqueous mixture with an increased solid content, said aqueous mixture with an increased solid content comprising the at least one enzyme and at least partially degraded and / or at least partially defibrillated cellulose, and a separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme;

[0169] (y-2) removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme, thereby obtaining the aqueous mixture with an increased solid content in separated form

[0170] (y-3) mixing the aqueous mixture with an increased solid content obtained in (y-2) with water and optionally with a stabilization agent, thereby obtaining an aqueous mixture with a re-decreased solid content;

[0171] (y-4) repeating step (y-1) based on the aqueous mixture with a re-decreased solid content obtained in (y-3), thereby obtaining: an aqueous mixture with an increased solid content, said aqueous mixture with an increased solid content comprising which comprises the at least one enzyme and at least partially degraded and / or at least partially defibrillated cellulose, and a separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme; 240406W001

[0172] - 20 -

[0173] (y-5) optionally removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme.

[0174] 37. The process of any one of embodiments 34 to 36, wherein the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme rand / or, preferably and, the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme is / are recycled into step (iv).

[0175] 38. Nanocellulose (at least partially degraded and / or at least partially defibrillated cellulose) obtained or obtainable from the process of any one of embodiments 1 to 37.

[0176] 39. A production unit for carrying out a process according to any one of embodiments 1 to 36 comprising a first shredding device SD(1) and a second shredding device SD(2), wherein SD(1) and SD(2) each have inlet means for introduction of solids, preferably dry solids, more preferably solid dry pieces p1 of a polymeric material comprising cellulose fibers and outlet means for removing shredded dry solid material; a heat adjustable vessel having inlet means for introducing shredded dry solid material, for introducing enzymes, and for introducing water; and having outlet means for removing an aqueous mixture; a milling device MD(1) having inlet means and outlet means, wherein at least one inlet means of the milling device MD(1) is preferably connectable or connected with at least one outlet means of the heat adjustable vessel by means for passing an aqueous mixture from the heat adjustable vessel to the milling device MD(1); a stirred media mill SMM having inlet means, wherein at least one inlet means of the stirred media mill SMM is connectable or connected with an outlet means of the milling device MD(1) by means for passing an aqueous mixture from the milling device MD(1) to the stirred media mill SMM, the stirred media mill SMM having at least one outlet means for removing an aqueous mixture.

[0177] 40. The production unit of embodiment 39 further comprising at least one solid liquid separation unit SLSU, preferably located in between the milling device MD(1) and the stirred media mill SMM and / or located downstream of the stirred media mill SMM, the at least one solid liquid separation unit SLSU having

[0178] - at least one inlet means connected with at least one outlet means of the milling device MD(1) and / or

[0179] - at least one inlet means preferably being connected with at least one outlet means of the stirred medial mill SMM by means for passing an aqueous mixture,

[0180] SLSU further having at least one outlet means for removing a liquid fraction, said at least one outlet means preferably being connectable or connected by at least one means for passing liquids with at least one inlet 240406W001

[0181] - 21 - means of the milling device MD (1 ), for transferring a liquid fraction from the solid separation unit SLSU to the milling device MD(1).

[0182] 41 . The production unit of embodiment 39 or 40 comprising at least one solid liquid separation unit SLSU located in between the milling device MD(1) and the stirred media mill SMM, the at least one solid liquid separation unit SLSU having at least one inlet means preferably being connected by at least one means for passing liquids with at least one outlet means of the milling device MD (1 ), SLSU further having at least one outlet means for removing a liquid fraction, said at least one outlet means preferably being connected by at least one means for passing liquids with at least one inlet means of the milling device MD (1 ), for transferring a liquid fraction from the solid separation unit SLSU to the milling device MD(1).

[0183] 42. The production unit of embodiment 41 , wherein the at least one solid liquid separation unit SLSU comprises at least one inlet mean for introducing water.

[0184] 43. The production unit of embodiment 39 or 40 comprising at least one solid liquid separation unit SLSU located downstream of the stirred media mill SMM, the at least one solid liquid separation unit SLSU having at least one inlet means preferably being connected by at least one means for passing liquids with at least one outlet means of the stirred media mill SMM, SLSU further preferably having at least one outlet means for removing a liquid fraction, said at least one outlet means preferably being connected by at least one means for passing liquids with at least one inlet means of the milling device MD(1 ), for transferring a liquid fraction from the solid separation unit SLSU to the milling device MD(1).

[0185] 44. Nanocellulose, preferably obtained or obtainable from the process of any one of embodiments 1 to 37, having in aqueous solution with a nanocellulose content in the range of 2.5 to 3.5 weight-% a viscosity of less than 10 mPa ■ s at a shear rate of 10 s1, preferably determined according to the method described herein below under M.1.

[0186] 45. The nanocellulose of embodiment 44 having in aqueous solution with a nanocellulose content in the range of 2.5 to 3.5 weight-% a viscosity of less than 5 mPa ■ s at a shear rate of 10 s1, preferably determined according to the method described herein below under M.1.

[0187] 46. The nanocellulose of embodiment 44 or 45, wherein an aqueous mixture thereof, preferably having a solid content in the range of from 0.1 to 10 weight-%, more preferably in the range of from 0.5 to 6 weight-%, is shear thinning (flow index < 1).

[0188] 47. The nanocellulose of any one of embodiments 44 to 46, preferably obtained or obtainable from the process of any one of embodiments 1 to 37, with a total energy input of in the range of from 100 to 800 kWh / t, preferably in the range of from 128 to 556 kWh, brought into the aqueous mixture per ton of aqueous mixture over said 240406W001

[0189] - 22 - process, more preferably in the range of from 50 to 300 kWh brought into the aqueous mixture per ton of aqueous mixture over said process.

[0190] 48. The nanocellulose of any one of embodiments 44 to 47, wherein an aqueous mixture thereof, preferably having a solid content in the range of from 0.1 to 10 weight-%, more preferably in the range of from 0.5 to 6 weight-%, more preferably in the range of from 1 to 2 weight-%, has a yield point of less than 10 Pa, preferably of less than 5 Pa, more preferably of less than 2 Pa, preferably determined according to the method described herein below under M.2.

[0191] 49. The nanocellulose of any one of embodiments 44 to 48, wherein the weight loss in thermogravimetric analysis (TGA) according to DIN 51006:2024 DE starts at 220°C and / or, wherein Tf (inflection point of the curve in the TGA diagram) is at about 305 °C, preferably for nanocellulose obtained from a total energy input of in the range of from 100 to 800 kWh / t, preferably in the range of from 128 to 556 kWh, brought into the aqueous mixture per ton of aqueous mixture.

[0192] 50. The nanocellulose of any one of embodiments 44 to 49, having an air flow resistance of < 100 ml / min, preferably of < 50 ml / min, preferably of < 10 ml / min, determined according to Bendtsen (ISO 5636-3:2013), preferably for a dry coating thereof on paper having a weight of in the range of from 1 to 10 g / m2, preferably in the range of from 3 to 9 g / m2, more preferably of 4 to 8 g / m2.

[0193] 51 . The nanocellulose of any one of embodiments 44 to 50, having a crystallinity determined according to ISO / TS 23361 in the range of from 70 to 80 %.

[0194] EXAMPLES

[0195] Methods

[0196] M.1 Viscosity

[0197] Viscosity was determined for nanocellulose in aqueous mixture in that a sample thereof was analysed via rheometry using an Anton Paar Rheometer (type MGR) at 20°C, wherein a shear rate ramp of 0.1 to 1000 1 / s was applied forth and back, which was conducted twice.

[0198] M.2 Yield point 240406W001

[0199] - 23 -

[0200] Yield point was determined as the shear stress limit at 20°C, wherein a round geometry was used with 25 mm diameter and 1 .0 mm gap. The shear rate was modified and the shear stress between 0.01 and 300 Pa was measured via rheometer.

[0201] 1 Nanocellulose preparation

[0202] Nanocellulose was prepared from Softwood Bleached Kraft Pulp according to the process of any one of embodiments 1 to 37 as described herein above, with a total energy input of in the range of from 100 to 800 kWh / t, preferably in the range of from 128 to 556 kWh, brought into the aqueous mixture per ton of aqueous mixture over said process, more preferably in the range of from 50 to 300 kWh brought into the aqueous mixture per ton of aqueous mixture over said process. The process was conducted as follows:

[0203] • Mixing of citrate buffer (237.5 ml), 2ater (4500 ml), Softwood bleached Kraft Pulp (250 g) in a 10 I vessel

[0204] • Heating the suspension to 50°C, duration about 30 minutes, wherein said period of time was referred to as "soaking time”

[0205] • Pre milling using a colloid mill type Fryma MZ 80, 350 pm gap size, untill 50 kWh / t were introduced into the suspension

[0206] • Adding enzyme CTEC3 (51 ml) 25 FPU / g

[0207] • Wait one hour to reduce viscosity from >1500 mPas to < 500 mPas

[0208] • Start milling using a Netzsch LabStar stirred media mill with LMZ rotortype, 0,4-0, 6 mm Zirconia milling beads, 80 % milling bead filling degree, 200 pm filter screen, 13 m / s circumferential speed, 25 kg / h feed rate in circular operation mode, adding additional 100 to 300 kWh / t to the suspension

[0209] • Centrifugation of the suspension at 3000g for < 15 Minutes to partially remove excess water, glucose and enzymes, resulting in a paste like aqueous nanocellulose mixture (NC paste) of 15 weight- % solids content.

[0210] 2 Viscosity

[0211] 2. 1 Viscosity in relation to shear rate

[0212] Nanocellulose in aqueous mixture was prepared as described herein above under 1., wherein the aqueous mixture had a solid content of 5.08 weight-% nanocellulose. The viscosity of the nanocellulose was determined according to M.1 described herein abovefor the mixture having a solid content of 5.08 weight-% nanocellulose. The viscosity was also determined in that way for aqueous mixtures, wherein the solid content was reduced by water addition to 2.97 weight-% and to 0.82 weight-% respectively. As comparison, the viscosity was determined for a commercially available nanocellulose of company Sappi Valida (CAS no. 9004-34-6) in aqueous mixture with an initial solid content of 2.97 weight-%, which was further reduced by water addition to 0.82 weight-%. The results are graphically depicted in Figures 1 to 3, wherein Fig. 1 shows the viscosity results for the three samples of the inventive nanocellulose with solid content of about 5 weight-% (5.08 weight-%), about 3 weight-% (2.97 weight-%) and about 0.8 weight-% (0.82 weight-%) in comparison. 240406W001

[0213] - 24 -

[0214] It was apparent that the commercially available nanocellulose at a solid content (SC) of about 3 weight-% (2.97 weight- %) had a significantly higher viscosity than the inventive nanocellulose at the same solid content of the aqueous mixture of about 3 weight-% (2.97 weight-%); reference is made to Fig. 2. Already at a shear rate of 1 Is, the difference was about 1000 Pa ■ s. At a shear rate of 10 / s, the viscosity of the inventive nanocellulose with a solid content of about 3 weight-% still had a viscosity clearly below 10 Pa ■ s, even more less than 1 Pa ■ s, where the commercially available cellulose at the same solid content of about 3 weight-% still had a viscosity of more than 10 Pa ■ s, even more than 50 Pa ■ s.

[0215] Upon visual inspection, a glass containing the aqueous mixture of the commercially available nanocellulose at a solid content of about 3 weight-% could be turned upside down, while the mixture stayed within the glass without flowing down, whereas turning a glass containing the aqueous mixture of the commercially available nanocellulose at a solid content of about 3 weight-% upside down resulted in the mixture flows out of the glass.

[0216] The same is apparent from Fig. 3, i.e. the commercially available nanocellulose at a solid content (SC) of about 0.8 weight-% (0.82 weight-%) had a significantly higher viscosity than the inventive nanocellulose at the same solid content of the aqueous mixture of about 0.8 weight-% (0.82 weight-%). Already at a shear rate of 1 Is, the difference was about 100 Pa ■ s. At a shear rate of 10 / s, the viscosity of the inventive nanocellulose with a solid content of about 0.8 weight-% (0.82 weight-%) still had a viscosity clearly below 10 Pa ■ s, even more less than 1 Pa ■ s, even more less than 0.1 Pa ■ s, where the commercially available cellulose at the same solid content of about 0.8 weight-% (0.82 weight-%) still had a viscosity of much more than 1 Pa ■ s.

[0217] 2.2 Shear thickening versus shear thinning

[0218] Furthermore, as apparent from Figures 1, 2 and 3, an aqueous mixture of the commercially available nanocellulose was shear-thickening. For determination whether an aqueous mixture has shear thinning or shear thickening behavior, the viscosity was determined in relation to shear rate wherein a certain range of numbers of revolution is repeatedly passed to achieved different shear rates. Said process was stopped and then repeated. As known to the skilled person, shear thickening systems start with a lower viscosity and then become thicker over time / passages, whereas shear thinning systems have a certain viscosity and then become thinner over time / passages.

[0219] The relation of shear stress (T) and applied shear rate (y) is expressed by equation [1]

[0220] T = K-yn[1] where Kis a material-based constant n is the flow index.

[0221] Shear thickening solutions have a flow index n, which is greater than 1 (n > 1), shear thinning solutions have a flow index n, which is smaller than 1 (n < 1). 240406W001

[0222] - 25 -

[0223] Contrary to the aqueous mixture of the commercially available nanocellulose, all aqueous mixtures of the inventive nanocellulose, irrespective of their solid content, showed a shear thinning behavior, starting at a certain viscosity, which then decreased significantly and stayed low even at repetition. Thus, the aqueous mixtures of the inventive nanocellulose have a flow index n < 1.

[0224] 3 Yield point

[0225] Nanocellulose in aqueous mixture was prepared as described herein above in 1 . The yield point was determined according to M.2 as described herein above, wherein the curves were fitted according to the Herschel / Bulky method. All aqueous mixtures were adjusted to a solid content of 1 .4 weight-%. For comparison, a commercially available nanocellulose ((Exilva from Borregaard, CAS no. 9004-34-6) was used, also as aqueous mixture with a solid content of 1.4 weight-%. The resulting yield points are shown below in Table 1 :

[0226] Table 1

[0227] Yield point for inventive nanocellulose in relation to total energy input

[0228] It was apparent that the commercially available nanocellulose had a significantly higher yield point, wherein the aqueous mixtures of the inventive nanocellulose had all yield points below 10 Pa, preferably below 5 Pa, more preferably below 2 Pa.

[0229] 4 Crystallinity

[0230] Commercially available nanocellulose normally has a crystallinity in the range of from 70 to 80 %, determined according to ISO / TS 23361.

[0231] Crystallinity was determined according to ISO / TS 23361 via X ray diffraction (XRD) for the inventive nanocellulose prepared as described herein above with a total energy input of in the range of from 50 to 300 kWh brought into the aqueous mixture per ton of aqueous mixture, wherein the data were evaluated based on the Segal method. The results are shown in Table 2 below:

[0232] Table 2

[0233] Crystallinity values for inventive nanocellulose in relation to total energy input 240406W001

[0234] - 26 -

[0235] The inventive nanocellulose had, in the range of total energy input of in the range of from 50 to 300 kWh brought into the aqueous mixture per ton of aqueous mixture a crystallinity in the range of from 70 to 80 %.

[0236] However it was found that with further energy intake the crystallinity can be further reduced down to 50% or more, which indicated an amorphization.

[0237] 5 Thermogravimetric analysis

[0238] Thermogravimetric analysis (TGA) was conducted according to DIN 51006:2024 DE for the inventive nanocellulose prepared as described herein above with a total energy input of 350 kWh brought into the aqueous mixture per ton of aqueous mixture. The result is shown in Fig. 4. As could be seen, the weight loss started at 220°C and Tf (inflection point of the curve in the TGA diagram) was at about 305 °C.

[0239] 6 Barrier properties

[0240] Paper (kraft liner, unbleached) was coated with a layer of the inventive nanocellulose and cmparative nanocellulose of 5. The inventive nanocellulose was applied as aqueous mixture via spray coating with a solid content of 2.6 weight-% and 3.3 weight-% respectively. The aqueous mixture of comparative nanocellulose had to be diluted down to 1 weight-% as other ways no spray coating was possible. All coatings were applied with a weight of about 6 g / m2. Air permeability / air flow resistance was determined according to Bendtsen (ISO 5636-3:2013). For that purpose, the coated papers were stored at 50 % relative humidity and 22°C for 24 hours and afterwards analysed. The results are shown in Table 3 below.

[0241] Table 3

[0242] Barrier properties of inventive versus commercially available nanocellulose on paper (kraft liner, unbleached) 240406W001

[0243] - 27 -

[0244] It was found that the inventive nanocellulose allowed for an almost complete barrier against air permeation, whereas the comparative nanocellulose was only slightly better with respect to air flow resistance than the uncoated paper. Short description of the Figures

[0245] Fig. 1 shows the viscosity results for the three samples of the inventive nanocellulose with solid content of about 5 weight-% (5.08 weight- %), about 3 weight-% (2.97 weight- %) and about 0.8 weight-% (0.82 weight-%) in comparison; Fig. 2 shows the viscosity results for a sample of the inventive nanocellulose with solid content of about 3 weight-% (2.97 weight-%) and of a commercially available nanocellulose with solid content of about 3 weight-% (2.97 weight-%) in comparison;

[0246] Fig. 3 shows the viscosity results for a sample of the inventive nanocellulose with solid content of about 0.8 weight-% (0.82 weight-%) and of a commercially available nanocellulose with solid content of about 0.8 weight-% (0.82 weight-%) in comparison;

[0247] Fig. 4 shows the results of a thermogravimetric analysis of a sample of the inventive nanocellulose;

Claims

240406W001- 28 -Claims1 . A process for preparing nanocellulose from a polymeric material comprising cellulose fibers, the process comprising:(i) Providing pieces p1 of the polymeric material comprising cellulose fibers;(II) Shredding the pieces p1 provided according to (I) in n shredding devices SD(i) wherein n is an integer with n>1 and 1=1 ...n, thereby obtaining pieces p2, which comprise cellulose fibers;(ill) Preparing an aqueous mixture comprising the pieces p2 at a temperature T 1 and adjusting the temperature of the aqueous mixture comprising the pieces p2 to a temperature T2 with T2 > T1 , thereby obtaining an aqueous mixture comprising the pieces p2 and having temperature T2;(iv) Introducing at least one enzyme capable of degrading cellulose (cellulase) into the aqueous mixture obtained according to (ill), thereby obtaining an aqueous mixture comprising the pieces p2 and at least one enzyme, wherein the aqueous mixture has temperature T2;(v) Optionally milling the aqueous mixture obtained according to (iv) in a milling device MD(1), thereby obtaining an aqueous mixture comprising the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers;(vi) Milling the aqueous mixture obtained according to (iv) or (v) in a stirred media mill SMM, thereby obtaining an aqueous mixture comprising the at least one enzyme and nanocellulose (at least partially degraded and / or at least partially defibrillated cellulose).

2. The process of claim 1 , wherein the polymeric material comprising cellulose fibers is a cellulose based textile or a cellulose pulp, preferably a cellulose pulp.

3. The process of claim 1 or 2, wherein the n shredding devices SD(i) comprise at least a first shredding device SD(1 ) and a second shredding device SD(2), wherein(II) preferably comprises:(11.1) Shredding the pieces p1, which have a bulk density bdpiand a length lpi, provided according to (I) in the first shredding device SD(1), thereby obtaining pieces p1-1, which comprise cellulose fibers, wherein the pieces p1 -1 have a length with lpi-i < lp-i ;(11.2) Shredding the pieces p1 -1 obtained according to (ii-1) in the second shredding device SD(2), thereby obtaining pieces p2, which comprise cellulose fibers, wherein the pieces p2 have a bulk density bdP2 with bdP2 < bdpi.

4. The process of any one of claims 1 to 3, wherein the n shredding devices SD(i), preferably the first shredding device SD(1) and the second shredding device SD(2), are selected from the group consisting of a shredder, a guillotine, a hammer mill, and a cutting mill, wherein SD(1) is preferably a shredder, the shredder being more preferably a double-shaft shredder or a four-shaft shredder and / or SD(2) is preferably a hammer mill.240406W001- 29 -5. The process of any one of claims 1 to 4, wherein the pH value of the aqueous mixture comprising the pieces p2 is adjusted in step (iii) to be in the range of from 3 to 6, preferably in the range of from 4 to 5, more preferably in the range of from 4.2 to 4.8, preferably by addition of an aqueous solution comprising at least one buffer; and / or wherein in step (iv) together with or prior to the introduction of the at least one enzyme, the pH value of the aqueous mixtures is adjusted to be in the range of from 3 to 6, preferably in the range of from 4 to 5, more preferably in the range of from 4.2 to 4.8, preferably by addition of an aqueous solution comprising at least one buffer.

6. The process of any one of claims 1 to 5, wherein T1 is a temperature in the range of from 10 to 40°C and T2 is a temperature suitable for the at least one enzyme for degrading cellulose (cellulase) with T2, with T2 > T1 .

7. The process of any one of claims 1 to 6, wherein step (iii) comprises:(iii.1) Preparing an aqueous mixture comprising the pieces p2 having a viscosity .(1) at a temperature T1 and adjusting the temperature of the aqueous mixture comprising the pieces p2 to a temperature T2 with T2 > T1;(111.2) Optionally incubating the aqueous mixture comprising the pieces p2 at temperature T2 for a period of time of at least 1 minute;(111.3) Milling the aqueous mixture of step (iii.1) or of step (iii.2) for a period of time in a milling device MD(0), so that the total energy input in kWh brought into the aqueous mixture per ton of aqueous mixture is in the range of from 10 to 100 kWh / t, preferably in the range of from 40 to 80 kWh / t; thereby obtaining an aqueous mixture comprising the pieces p2 and having a viscosity .(2), with .(2) < .(1).

8. The process of any one of claims 1 to 7, wherein the enzyme capable of degrading cellulose introduced in step (iv) is a cellulase, preferably selected from the group consisting of beta-glucosidase, endo-1,4-beta-D- glucanase, exo-1,4-beta-D-glucanase and mixtures of two or more of these enzymes.

9. The process of any one of claims 1 to 8, wherein the milling device MD(1) is a mill with rotor stator geometry or a stirred media mil.

10. The process of claim 9, wherein the milling device MD(1) is a stirred media mill SMM(MD(1)), which preferably comprises a dynamic gap separation system with a dynamic gap opening in the range of from 0.5 to 2 mm, preferably in the range of from 0.8 to 1.5 mm, more preferably in the range of from 0.9 to 1.1 mm.

11. The process of any one of claims 1 to 10, wherein at least in one step of (iv), (v) and (vi), preferably in each step (iv), (v) and (vi), the temperature of the respective aqueous mixture is maintained at T2; and / or, preferably and, wherein at least in one step of (iv), (v) and (iv), preferably in each step (iv), (v) and (vi), the pH value is adjusted or maintained in the range of from 4.0 to 6.0, preferably in the range of from 4.5 to 5.5.240406W001- 30 -12. The process of any one of claims 1 to 11, further comprising after (v) and before (vi)(x-1) Increasing the solid content of the aqueous mixture obtained in (v), which comprises the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers, preferably by at least 1 weight-%, based on the total weight of the aqueous mixture being 100 weight-%, wherein increasing the solid content is preferably done by centrifugation; thereby obtaining an aqueous mixture with an increased solid content, said aqueous mixture with an increased solid content comprising at least a part of the at least one enzyme and milled pieces p3, which comprise at least partially degraded cellulose fibers, wherein said aqueous mixture with an increased solid content is then subjected to the milling step according to (vi); and obtaining a separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme;(x-2) Optionally removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme.

13. The process of any one of claims 1 to 12, further comprising after (vi)(y-1) Increasing the solid content of the aqueous mixture obtained in (vi), which comprises the at least one enzyme and at least partially degraded and / or at least partially defibrillated cellulose, preferably by at least 1 weight-%, based on the total weight of the aqueous mixture being 100 weight-%, wherein increasing the solid content is preferably done by centrifugation; thereby obtaining an aqueous mixture with an increased solid content, said aqueous mixture with an increased solid content comprising the at least one enzyme and at least partially degraded and / or at least partially defibrillated cellulose, and a separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme;(y-2) removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme, thereby obtaining the aqueous mixture with an increased solid content in separated form(y-3) mixing the aqueous mixture with an increased solid content obtained in (y-2) with water and optionally with a stabilization agent, thereby obtaining an aqueous mixture with a re-decreased solid content;(y-4) repeating step (y-1) based on the aqueous mixture with a re-decreased solid content obtained in (y-3), thereby obtaining: an aqueous mixture with an increased solid content, said aqueous mixture with an increased solid content comprising which comprises the at least one enzyme and at least partially degraded and / or at least partially defibrillated cellulose, and a separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme;(y-5) optionally removing the separated liquid part, which comprises dissolved glucose and at least a part of the at least one enzyme.240406W001- 31 -14. A production unit for carrying out a process according to any one of claims 1 to 13 comprising a first shredding device SD(1) and a second shredding device SD(2), wherein SD(1) and SD(2) each have inlet means for introduction of solids, preferably dry solids, more preferably solid dry pieces p1 of a polymeric material comprising cellulose fibers and outlet means for removing shredded dry solid material; a heat adjustable vessel having inlet means for introducing shredded dry solid material, for introducing enzymes, and for introducing water; and having outlet means for removing an aqueous mixture; a milling device MD(1 ) having inlet means and outlet means, wherein at least one inlet means of the milling device MD(1 ) is preferably connectable or connected with at least one outlet means of the heat adjustable vessel by means for passing an aqueous mixture from the heat adjustable vessel to the milling device MD(1); a stirred media mill SMM having inlet means, wherein at least one inlet means of the stirred media mill SMM is connectable or connected with an outlet means of the milling device MD(1 ) by means for passing an aqueous mixture from the milling device MD(1 ) to the stirred media mill SMM, the stirred media mill SMM having at least one outlet means for removing an aqueous mixture.

15. Nanocellulose, preferably obtained or obtainable from the process of any one of claims 1 to 13, having in aqueous solution with a nanocellulose content in the range of 2.5 to 3.5 weight-% a viscosity of less than 10 mPa ■ s at a shear rate of 10 s1..

16. The nanocellulose of claim 15, wherein an aqueous mixture thereof having a solid content in the range of from 0.1 to 10 weight-%, preferably in the range of from 0.5 to 6 weight-%, is shear thinning (flow index < 1).

17. The nanocellulose of claim 15 or 16, wherein an aqueous mixture thereof having a solid content in the range of from 0.1 to 10 weight-%, preferably in the range of from 0.5 to 6 weight-%, more preferably in the range of from 1 to 2 weight-%, has a yield point of less than 10 Pa, preferably of less than 5 Pa, more preferably of less than 2 Pa.

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