Lignin microstructure, process to make the lignin microstructure thereof and uses thereof

Abstract

The disclosure relates to a lignin microstructure remarkable in that the lignin microstructure presents an outer layer being a nanocomposite structure comprising lignin and one or more components comprising and / or acting as one or more active biological ingredients and / or one or more sacrificial templates.

Description

[0001] DESCRIPTION

[0002] LIGNIN MICROSTRUCTURE, PROCESS TO MAKE THE LIGNIN MICROSTRUCTURE THEREOF AND USES THEREOF

[0003] FIELD OF THE DISCLOSURE

[0004] The present disclosure relates to lignin microstructures, in particular lignin microspheres or lignin microcapsules, as well as to suspensions of lignin microstructures thereof and organogels of the suspensions thereof. In addition, the present disclosure also relates to process to make the lignin microstructures or the suspensions thereof, as well as to the use of such lignin microstructures.

[0005] BACKGROUND OF THE DISCLOSURE

[0006] Lignin, is known as the second most abound biopolymer next to cellulose, but only a small fraction (about 5%) of it is actually used (ChemSusChem, 2020, 13, 4385-4393), notably as carriers for biologicially active substances. The several advantageous properties (such as antimicrobial, antioxidants, UV-adsoprtion, water-retaining properties) of lignin make it an interesting material for such applications, for example in nanomedicine and biocatalysis.

[0007] Entrapment, encapsulation, and adsorption are the common methods for loading active substances into lignin materials, as described in the review entitled “Lignin for Nano- and Microscaled Carrier Systems: Applications, Trends and Challenges" (ChemSusChem, 2019, 12, 2039-2054).

[0008] With respect to entrapment, lignin nanoparticles are formed by supramolecular assembly of poorly water-soluble molecule domains through electrostatic interactions between aromatic rings.

[0009] This allows to entrap low molecular weight compounds with low water solublity, such as pesticides, including insecticides, herbicides and / or microbicides. By performing this methodology, the active substances are within the core of the lignin nanoparticles, and the release of such active substances is made by diffusion from the core to the external environment of the lignin material, or dissolution of a shell (for example a polymer shell) if any, followed by diffusion from the core to the external environment.

[0010] With respect to encapsulation, lignin nanoparticles having a shell made of lignin and a core made of oil, or of at least water-immiscible liquid, are fabricated. In one example, the shell made of lignin is made by layer-by-layer adsorption onto crytals of active substances. This allows to encapsulate notably lipophilic drugs as well as herbicides. The release of such active substances is either performed by diffusion through the lignin shell from the oil core to the external environment of the lignin material, or by shell rupture.

[0011] With respect to adsorption, the active substance, such as enzymes, can be adsorbed onto the lignin particles, namely on the external surface of the lignin particles. During release, the active substance is simply desorbed.

[0012] There is therefore a need to provide a lignin microstructure that can be loaded with hydrophilic active substance.

[0013] SUMMARY OF THE DISCLOSURE

[0014] According to a first aspect, the disclosure concerns a lignin microstructure remarkable in that the lignin microstructure presents an outer layer being a nanocomposite structure comprising lignin and one or more components comprising and / or acting as one or more active biological ingredients and / or one or more sacrificial templates.

[0015] In particular, the disclosure concerns a lignin microstructure remarkable in that the lignin microstructure presents an outer layer being a nanocomposite structure comprising lignin and one or more components comprising and / or acting as one or more active biological ingredients and / or one or more sacrificial templates, and in that said lignin microstructure further presents one or more internal voids as evidenced by scanning electron microscopy, wherein said lignin microstructure is a lignin microsphere or a lignin microcapsule.

[0016] Surprisingly, it has been found that the lignin microstructure of the present disclosure have an outer layer that is a nanocomposite material, namely a biphasic material comprising, on one hand, a polymeric structure made of lignin and, on the other hand, any kind of components, including / comprising and / or acting as one or more active biological ingredients and / or one or more sacrificial templates, exhibits hydrophilic properties and can thus be loaded with a large panel of one or more hydrophilic active substances.

[0017] As any kind of components can be integrated into the nanocomposite structure forming the outer layer of the lignin microstructure, it is therefore possible to obtain a lignin microstructure which comprises hydrophilic components. The versatility of the lignin microstructure of the present disclosure is therefore very interesting, rendering them very useful for various implementations. This has the advantage of providing to the lignin microstructure the properties of either to be used as a carrier system, or to be transformed into a lignin microstructure which can have a porous outer layer.

[0018] For example, the one or more components within the outer layer, namely the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates, have a molecular mass ranging between 100 Da (100 g / mol) and 50000 Da (50000 g / mol), or between 150 Da and 45000 Da, or between 200 Da and 40000 Da, or between 250 Da, and 35000 Da, or between 300 Da and 30000 Da.

[0019] Advantageoulsy, the one or more components within the outer layer, namely the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates, are selected from one or more hydrophilic components, one or more hydrophobic components, one or more amphiphilic components, or any combination thereof. With preference, the one or more components within the outer layer are one or more hydrophilic components.

[0020] Advantageously, the lignin microstructure further presents one or more internal voids as evidenced by scanning electron microscopy.

[0021] - With preference, said one or more internal voids are at least partially filled with one or more fluids. For example, said one or more fluids are selected from one or more liquids, air, or a combination thereof.

[0022] - With preference, the one or more internal voids form one or more internal channels and / or one or more internal pores. For example, the lignin microstructure presents more than one internal void and each of said internal voids is interconnected with each other and / or in fluidic connection with each other. For example, said one or more internal voids have an average diameter size ranging between 2 nm and 500 nm as determined by scanning electron microscospy, more preferably between 5 nm and 450 nm, even more preferably between 10 nm and 400 nm, most preferably between 15 nm and 350 nm, even most preferably between 20 nm and 300 nm, or between 25 nm and 250 nm.

[0023] Advantageously, the outer layer is non-porous. This is evidenced by scanning electron microscopy.

[0024] For example, the lignin of the lignin microstructure is selected from Kraft lignin, soda lignin, lignosulfonate lignin, organosolv lignin, enzymatically hydrolyzed lignin, mechanically extracted lignin or a combination thereof. More preferably, the lignin of the lignin microstructure is Kraft lignin.

[0025] For example, the one or more components within the outer layer, namely the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates, are in an amount ranging between 0.1 wt.% and 40 wt.% of the total weight of the lignin microstructure, as determined by liquid chromatography mass spectrometry analysis, preferably between 0.5 wt.% and 35 wt.%, more preferably between 1 wt.% and 30 wt.%, or between 5 wt.% and 20 wt.%.

[0026] For example, the lignin microstructure shows a diameter D ranging between 500 nm and 500 pm as determined by scanning electron microscopy, more preferably between 750 nm and 250 pm, even more preferably between 1 pm and 100 pm, or between 5 pm and 90 pm.

[0027] According to a first preferred embodiment, the lignin microstructure is a lignin microsphere, wherein the lignin microsphere shows a volume V and further presents one or more internal voids which have a volume inferior to 50% of the volume of the lignin microstructure, as evidenced by scanning electron microscopy, said one or more internal voids being dispersed into a solid matrix. With preference, the one or more internal voids have a volume inferior to 45% of the volume of the lignin microstructure, more preferably inferior to 40%. With preference, the lignin microspere presents more than one internal void, and each of said internal voids is interconnected with each other. With preference, the nanocomposite structure of the outer layer further presents at least one surfactant as evidenced by scanning electron microscopy. For example, the lignin microsphere shows a diameter D and the size of the thickness of the outer layer is ranging between above 25% and below or equal to 50% of the diameter D as determined by scanning electron microscopy, preferably above 35%, or above 40% or above 45%.

[0028] According to a second preferred embodiment, alternative to the first embodiment, the lignin microstructure is a lignin microcapsule, wherein the lignin microcapsule shows a diameter D and wherein the size of the thickness of the outer layer is ranging below 25% of the diameter D as determined by scanning electron microscopy, preferably below 20% or below 15%, or below 10%. With preference, the size of the thickness of the outer layer is ranging between 1 % and 10% of the diameter D as determined by scanning electron microscopy. Advantageously, the lignin microstructure shows a volume V and further presents one or more internal voids which have a volume of at least 50% of the volume of the lignin microstructure, as evidenced by scanning electron microscopy, more preferably of at least 55%, even more preferably of at least 60%.

[0029] According to a second aspect, the disclosure concerns a suspension of lignin microsphere, as defined in the first embodiment, in one or more liquids selected from the group comprising one or more natural oils, one or more synthetic oils, one or more aprotic polar solvents or a mixture thereof. With preference, said suspension comprises between 1 wt.% and 20 wt.% of the lignin microsphere based on the total weight of said solvent-in-oil emulsion, more preferably between 2 wt.% and 18 wt.%, even more preferably between 5 wt.% and 15 wt.%.

[0030] According to a third aspect, the disclosure concerns an organogel remarkable in that it comprises the suspension as defined in accordance with the third aspect, and one or more gelling agents. With preference, said organogel comprises between 1 wt.% and 20 wt.% of one or more gelling agents based on the total weight of said organogel, more preferably between 2 wt.% and 18 wt.%, even more preferably between 5 wt.% and 15 wt.%.

[0031] According to a fourth aspect, the disclosure concerns a suspension of lignin microcapsule as defined in the second embodiment, in one or more liquids selected from the group comprising one or more natural oils, one or more synthetic oils, one or more aprotic polar solvents or a mixture thereof; with preference, said suspension comprises between 1 wt.% and 20 wt.% of the lignin microcapsule based on the total weight of said solvent-in-oil emulsion, more preferably between 2 wt.% and 18 wt.%, even more preferably between 5 wt.% and 15 wt.%.

[0032] According to a fifth aspect, the disclosure concerns an organogel remarkable in that it comprises the suspension as defined in accordance with the fourth aspect, and one or more gelling agents. With preference, said organogel comprises between 1 wt.% and 20 wt.% of one or more gelling agents based on the total weight of said organogel, more preferably between 2 wt.% and 18 wt.%, even more preferably between 5 wt.% and 15 wt.%.

[0033] According to a sixth aspect, the disclosure concerns a process to make a suspension of lignin microsphere as defined in the first embodiment or of lignin microcapsule as defined in the second embodiment, said process is remarkable in that it comprises the following steps: a) providing lignin, b) providing a first type of one or more solvents; c) mixing the first type of one or more solvents provided at step (b) and the lignin provided at step (a) to form a first mixture; d) fractionating the first mixture formed at step (c), so as to recover at least a first soluble fraction of the lignin in said first type of one or more solvents; e) optionally, recovering a precipate at step (d) and washing said precipitate with a second type of one or more solvents, so as to recover a second soluble fraction of the lignin in said second type of one or more solvents; f) preparing a solution of one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into said first type of one or more solvents; g) mixing the solution prepared at step (f) with the first soluble fraction of the lignin recovered at step (d), or when step (e) is carried out, with the second soluble fraction of the lignin recovered at step (e), so as to form respectively a second mixture or a third mixture, said second mixture comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents; said third mixture comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents and the second type of one or more solvents; h) providing one or more liquids immiscible with the first type of one or more solvents provided at step (b); said one or more liquids being miscible with the second type of one or more solvents used at step (e) when step (e) is carried out; i) adding the second mixture formed at step (g) or when step (e) is carried out, adding dropwise the third mixture formed at step (g) into the one or more liquids provided at step (h) so as to form respectively an emulsion comprising the second mixture or an emulsion comprising the third mixture; the emulsion being in the one or more liquids provided at step (h), j) evaporating the first type of one or more solvents and, when step (e) is carried out, the second type of one or more solvents, so as to form a suspension in the one or more liquids provided at step (h) of respectively lignin microsphere as defined in the first embodiment or of lignin microcapsule as defined in the second embodiment; wherein said first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) is at least partially soluble in said first type of one or more solvents and when step (e) is carried out, said second type of one or more solvents is different than the first type of one or more solvents.

[0034] Advantageously, the first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) has a solubilty of at least 10% as determined by a solubility test A into said first type of one or more solvents, namely ranging between 10% and 100% as determined by a solubility test A, or between 15% and 90%, or between 20% and 80%.

[0035] Advantageously, when the one or more liquids provided at step (h) are mixed with the first type of one or more solvents provided at step (b) to form a first liquid pair, the absorbance of the first liqud pair is superior than 0.05 AU as determined by a solublity test B, preferably superior than 0.06 AU, more preferably superior than 0.07 AU. Advantageously, when step (e) is carried out, and when the one or more liquids provided at step (h) are mixed with the second type of one or more solvents used at step (e) to form a second liquid pair, the absorbance of the second liquid pair is lower or equal to 0.05 AU as determined by a solubiity test B, preferably lower than 0.04 AU, more preferably lower than 0.03 AU.

[0036] For example, the first type of one or more solvents provided at step (b) and / or the second type of one or more solvents used at step (e) when step (e) is carrired out are selected from the group comprising acetone, methanol, ethanol, 1 -propanol, iso- propanol, 1 -butanol, ethylene glycol, ethyl acetate, ethyl lactate, / so-propyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof.

[0037] With respect to the suspension of lignin microsphere as defined in the first embodiment the process to make them is remarkable in that it comprises the following steps: a) providing lignin, b) providing a first type of one or more solvents; c) mixing the first type of one or more solvents provided at step (b) and the lignin provided at step (a) to form a first mixture; d) fractionating the first mixture formed at step (c), so as to recover at least a first soluble fraction of the lignin in said first type of one or more solvents; f) preparing a solution of one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into said first type of one or more solvents; g) mixing the solution prepared at step (f) with the first soluble fraction of the lignin recovered at step (d), so as to form a second mixture, said second mixture comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents; h) providing one or more liquids immiscible with the first type of one or more solvents provided at step (b); i) adding the second mixture formed at step (g) into the one or more liquids provided at step (h) so as to form an emulsion comprising the second mixture; the emulsion being in the one or more liquids provided at step (h), j) evaporating the first type of one or more solvents, so as to form a suspension in the one or more liquids provided at step (h) of lignin microsphere as defined in the first embodiment; wherein said first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) is at least partially soluble in said first type of one or more solvents.

[0038] For example, the first type of one or more solvents provided at step (b) is selected from the group comprising acetone, methanol, ethanol, 1 -propanol, / so-propanol, 1 -butanol, ethylene glycol, ethyl acetate, ethyl lactate, / so-propyl acetate, tetrahydrofuran, 2- methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof; more preferably ethanol and / or / so-propanol; even more preferably ethanol.

[0039] Advantageously, the solution prepared at step (f) further comprises one or more surfactants, so as to form after step (j) a suspension in the one or more liquids provided at step (h) of lignin microsphere in which the nanocomposite structure of the outer layer further presents at least one surfactant as evidenced by scanning electron microscopy. For example, the solution prepared at step (f) further comprises one or more surfactants in an amount ranging between 0.01 wt.% and 20.00 wt.% of said solution prepared at step (f), preferably between 0.05 wt.% and 19.00 wt.%, more preferably between 0.10 wt.% and 18.00 wt.%, even more preferably between 0.50 wt.% and 17.00 wt.%, most preferably between 1 .00 wt.% and 16.00 wt.% or between 5.00 wt.% and 15.00 wt.%.

[0040] With respect to the suspension of lignin microcapsule as defined in the second embodiment, the process to make them is remarkable in that it comprises the following steps: a) providing lignin, b) providing a first type of one or more solvents; c) mixing the first type of one or more solvents provided at step (b) and the lignin provided at step (a) to form a first mixture; d) fractionating the first mixture formed at step (c), so as to recover at least a first soluble fraction of the lignin in said first type of one or more solvents; e) recovering a precipate at step (d) and washing said precipitate with a second type of one or more solvents, so as to recover a second soluble fraction of the lignin in said second type of one or more solvents; f) preparing a solution of one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into said first type of one or more solvents; g) mixing the solution prepared at step (f) with the second soluble fraction of the lignin recovered at step (e), so as to form a third mixture; said third mixture comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents and the second type of one or more solvents; h) providing one or more liquids immiscible with the first type of one or more solvents provided at step (b); said one or more liquids being miscible with the second type of one or more solvents used at step (e); i) adding dropwise the third mixture formed at step (g) into the one or more liquids provided at step (h) so as to form an emulsion comprising the third mixture; the emulsion being in the one or more liquids provided at step (h), j) evaporating the first type of one or more solvents and the second type of one or more solvents, so as to form a suspension in the one or more liquids provided at step (h) of lignin microcapsule as defined in the second embodiment; wherein said first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) is at least partially soluble in said first type of one or more solvents and wherein said second type of one or more solvents is different than the first type of one or more solvents.

[0041] Advantageously, the first type of one or more solvents provided at step (b) and the second type of one or more solvents used at step (e) are selected from the group comprising acetone, methanol, ethanol, 1 -propanol, / so-propanol, 1 -butanol, ethylene glycol, ethyl acetate, ethyl lactate, / so-propyl acetate, tetrahydrofuran, 2- methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof. According to the seventh aspect, the disclosure concerns a process to make lignin microsphere as defined in the first embodiment or lignin microcapsule as defined in the second embodiment remarkable in that it comprises the process to make a suspension in accordance with the fifth aspect, followed by the step (k) of separating the lignin microsphere as defined in the first embodiment or the ligin microcapsule as defined in the second embodiment from the one or more liquids provided at step (h).

[0042] According to the eighth aspect, the disclosure comprises a process to obtain respectively a lignin microsphere or a ligin microcapsule with an outer layer consisting of or comprising porous lignin, said process comprising the process to make lignin microsphere or lignin microcapsule in accordance with the seventh aspect, followed by the step (m) of providing a third type of one or more solvents and the step (n) of washing the lignin microsphere as defined in the first embodiment or the ligin microcapsule as defined in the second embodiment with the third type of one or more solvents provided at step (m), so as to obtain respectively a lignin microsphere or a ligin microcapsule with an outer layer consisting of or comprising porous lignin, wherein the third type of one or more solvents are selected so that the components acting as one or more active biological ingredients and / or one or more sacrificial templates provided at step (f) are at least partially soluble into said third type one or more solvents. With preference, the third type of one or more solvents provided at step (m) is selected so that the components acting as one or more active biological ingredients and / or one or more sacrificial templates provided at step (f) have a solublity of at least 10% as determined by a solubilty test C into said third type of one or more solvents, namely ranging between 10% and 100% as determined by a solubility test C, or between 15% and 90%, or between 20% and 80%.

[0043] For example, the third type of one or more solvents provided at step (m) is selected from the group comprising acetone, methanol, ethanol, 1 -propanol, / so-propanol, 1- butanol, ethylene glycol, ethyl acetate, ethyl lactate, / so-propyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof.

[0044] According to a nineth aspect, the disclosure concerns the process to make the organogel as defined in the third and / or fifth aspect, said process is remarkable in that it comprises the process according to the sixth aspect, followed after step (j), by the step (I) of adding one or more gelling agents into the suspension formed at step (j).

[0045] According to a tenth aspect, the disclosure concerns a use of the lignin microsphere as defined in the first embodiment, wherein the one or more components act as one or more active biological ingredients, in relase application.

[0046] According to a eleventh aspect, the disclosure concerns a use of the lignin microcapsule as defined in the second embodiment, wherein the one or more components act as one or more active biological ingredients, in relase application.

[0047] According to an twelveth aspect, the disclosure concerns a use of respectively a lignin microsphere or a ligin microcapsule with an outer layer consisting of or comprising porous lignin as produced by the process defined the eighth aspect as hydrophilic carrier system.

[0048] DESCRIPTION OF THE FIGURES

[0049] Figure 1 : Tridimentional representation of lignin microsphere in accordance with the present disclosure.

[0050] Figure 2: Tridimentional representation of lignin microcapsule in accordance with the present disclosure.

[0051] Figure 3: SEM image of lignin microcapsules with an outer layer made of porous lignin, wherein the nanocomposite structure of the outer layer was loaded with madecassoside before being washed with / so-propanol.

[0052] Figure 4: SEM image of lignin microcapsules with an outer layer made of porous lignin, wherein the nanocomposite structure of the outer layer was loaded with madecassoside before being washed with ethyl acetate.

[0053] Figure 5: FIB (Focused Ion Beams) cross-section of lignin microsphere loaded with ascorbic acid that has been washed with toluene (scale of 3 pm). Figure 6: FIB image of lignin microsphere loaded with ascorbic acid that has been washed with / so-propanol (scale of 2 pm), with an enlargement confirming that the lignin microstructure in question is not hollow and is thus a lignin microsphere.

[0054] Figure 7: SEM image after toluene washing of lignin microcapsules loaded with madecassoside (scale of 1 pm).

[0055] Figure 8: SEM image after toluene washing of control lignin microcapsules, i.e., of unloaded microcapsules (scale of 1 pm).

[0056] Figure 9: SEM image after toluene washing of lignin microcapsules loaded with madecassoside (scale of 500 nm)

[0057] Figure 10: SEM image after toluene washing of control lignin microcapsules, i.e., of unloaded microcapsules (scale of 500 nm).

[0058] Figure 11 : SEM image after / so-propanol washing of lignin microcapsules loaded with madecassoside (scale of 1 pm).

[0059] Figure 12: SEM image after / so-propanol washing of control lignin microcapsules, i.e., of unloaded microcapsules (scale of 1 pm).

[0060] Figure 13: SEM image after / so-propanol washing of lignin microcapsules loaded with madecassoside (scale of 500 nm).

[0061] Figure 14: SEM image after / so-propanol washing of control lignin microcapsules, i.e., of unloaded microcapsules (scale of 500 nm).

[0062] Figure 15: 2ndSEM image after / so-propanol washing of lignin microcapsules loaded with madecassoside (scale of 500 nm).

[0063] Figure 16: 2ndSEM image after / so-propanol washing of control lignin microcapsules, i.e., of unloaded microcapsules (scale of 500 nm).

[0064] Figure 17: FIB cross-section of lignin microcapsules loaded with madecassoside that have been washed with toluene (scale of 10 pm). Figure 18: FIB image of lignin microcapsule loaded with madecassoside that has been washed with / so-propanol (scale of 4 pm) with an enlargement of the outer layer comprising porous lignin (scale of 500 nm).

[0065] Figure 19: SEM image of lignin microcapsule with representation of release of madecassoside.

[0066] Figure 20: Results of release experiment using a lignin microcapsule loaded with madecassoside.

[0067] DETAILED DESCRIPTION OF THE DISCLOSURE

[0068] For the disclosure, the following definitions are given:

[0069] The expression “insoluble in a liquid or a solvent” means that 1 mg of the compound in question is dissolved in said liquid or said solvent when there is at least 100 ml of said liquid or said solvent. In other words, the concentration of the compound in question in said liquid or said solvent is less or equal to 0.01 mg / ml (10 pg / ml).

[0070] Also, “two liquids ( / .e., a first liquid and a second liquid) considered as immiscible” means that 1 mg of the first liquid is dissolved in at least 100 ml the second liquid. In other words, the concentration of the first liquid into the second liquid is less or equal to 0.01 mg / ml (10 pg / ml).

[0071] The terms "comprising", "comprises" and "comprised of" as used herein are synonymous with "including", "includes" or "containing", "contains", and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. The terms "comprising", "comprises" and "comprised of" also include the term “consisting of”.

[0072] The recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g., 1 to 5 can include 1 , 2, 3, 4, 5 when referring to, for example, a number of elements, and can also include 1 .5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of endpoints also includes the recited endpoint values themselves (e.g., from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein. The particular features, structures, characteristics or embodiments may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments.

[0073] The present disclosure concerns a lignin microstructure remarkable in that the lignin microstructure presents an outer layer being a nanocomposite structure comprising lignin and one or more components including / comprising and / or acting as one or more active biological ingredients and / or one or more sacrificial templates.

[0074] In particular, the disclosure concerns a lignin microstructure remarkable in that the lignin microstructure presents an outer layer being a nanocomposite structure comprising lignin and one or more components comprising and / or acting as one or more active biological ingredients and / or one or more sacrificial templates, and in that said lignin microstructure further presents one or more internal voids as evidenced by scanning electron microscopy, wherein said lignin microstructure is a lignin microsphere or a lignin microcapsule

[0075] Upon this definition, the lignin microstructure of the present disclosure has an outer layer which is non-porous, since it is made by lignin along with any kind of one or more components comprising and / or acting as one or more active biological ingredients and / or one or more sacrificial templates. In other words, the nanocomposite structure of the lignin microstructure is homogeneous and / or uniform, as evidenced by scanning electron microscopy. This ensure the versatility of the lignin microstructure of the present disclosure. If the one or more components comprise and / or act as one or more active biological ingredients, such as one or more active pharmaceutical ingredients, the lignin microstructure can be used as a carrier system for such one or more active biological ingredients. If the one or more components comprise and / or act as sacrificial templates, the lignin microstructure can be washed, namely digested, so as to remove those one or more components and forms a lignin microstructure with an outer layer consisting of or comprising porous lignin, the pores of the porous lignin being formed during the removal of said one or more components acting as sacrificial templates. Upon the efficiency of the digestion step, it is also possible to control the degree of porosity of the outer layer. It is further stated that the one or more active biological ingredients are also removed during the washing or the digestion, so that they also act as sacrificial templates. For example, the one or more components within the outer layer, namely the one or more components comprising and / or acting as one or more active biological ingredients and / or one or more sacrificial templates, have a molecular mass ranging between 100 Da and 50000 Da.

[0076] Advantageoulsy, the one or more components within the outer layer, namely the one or more components comprising and / or acting as one or more active biological ingredients and / or one or more sacrificial templates, are selected from one or more hydrophilic components, one or more hydrophobic components, one or more amphiphilic components, or any combination thereof. With preference, the one or more components within the outer layer are one or more hydrophilic components. Examples of hydrophilic components are madecassoside, ascorbic acid, rhodamine, glucose or even proteins.

[0077] For example, the one or more components are one or more molecules with a molecular mass below 1000 Da, preferably between 100 Da and 1000 Da, such as madecassoside, ascorbic acid, rhodamine, glucose, or a combination thereof.

[0078] For example, the one or more components are one or more molecules with a molecular mass ranging between 1000 Da and 5000 Da. For example, the one or more components are polymers and / or biopolymers, such as proteins, with a molecular mass ranging between 5000 Da and 50000 Da.

[0079] Advantageously, the lignin microstructure further presents one or more internal voids as evidenced by scanning electron microscopy. Those internal voids are at least partially or completely filled with one or mre fluids, such as one or more liquids, air, or any combination thereof. They can form one or more internal channels and / or one or more internal pores. Such voids are preferably interconnected with each other and / or in fluidic connection with each other, so as to form for example a network of internal channels within the lignin microstructure. The internal voids can have an average diameter size ranging between 2 nm and 500 nm as determined by scanning electron microscospy, more preferably between 5 nm and 450 nm, even more preferably between 10 nm and 400 nm, most preferably between 15 nm and 350 nm, even most preferably between 20 nm and 300 nm, or between 25 nm and 250 nm. For example, the lignin of the lignin microstructure is selected from Kraft lignin, soda lignin, lignosulfonate lignin, organosolv lignin, enzymatically hydrolyzed lignin, mechanically extracted lignin or a combination thereof. More preferably, the lignin of the lignin microstructure is Kraft lignin. Lignin is a polyphenol with a molecular weight ranging between 1000 g mol-1and 15000 g mol-1as determined by gel permeation chromatography, preferably between 2000 g mol-1and 14000 g mol’1, more preferably between 3000 g mol’1and 13000 g mol’1, even more preferably between 4000 g mol’1and 12000 g mol’1.

[0080] For example, the one or more components within the outer layer, namely the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates, are in an amount ranging between 0.1 wt.% and 40 wt.% of the total weight of the lignin microstructure, as determined by liquid chromatography mass spectrometry analysis, preferably between 0.5 wt.% and 35 wt.%, more preferably between 1 wt.% and 30 wt.%, or between 2 wt.% and 25 wt.%, or between 5 wt.% and 20 wt.%.

[0081] The lignin microstructure can be spherical. For example, the lignin microstructure shows a diameter D ranging between 500 nm and 500 pm as determined by scanning electron microscopy, more preferably between 750 nm and 250 pm, even more preferably between 1 pm and 100 pm, or between 5 pm and 90 pm.

[0082] In a first preferred embodiment, the lignin microstructure is a lignin microsphere (see figure 1 ). The lignin microsphere has an internal core with a volume superior to 50% of the total volume of the lignin microstructure. Such lignin microsphere has a volume V and can further presents one or more internal voids which have a volume inferior to 50% of the volume of the lignin microstructure, as evidenced by scanning electron microscopy, said one or more internal voids being dispersed into a solid matrix. The structure of the solid matrix is made of lignin. Such lignin microsphere has also a diameter D, and the size of the thickness of the outer layer is ranging between above 25% and below or equal to 50% of the diameter D as determined by scanning electron microscopy.

[0083] With preference, the one or more internal voids have a volume inferior to 45% of the volume of the lignin microstructure as evidenced by scanning electron microscopy, more preferably inferior to 40%, even more preferably inferior to 30%. The internal voids can be interconnected with each other and / or in fluidic connection with each other.

[0084] With preference, the size of the thickness of the outer laer is ranging above 35% of the diameter D as determined by scanning electron microscopy, or above 40% or above 45%.

[0085] With preference, the nanocomposite structure of the outer layer further presents at least one surfactant as evidenced by scanning electron microscopy. For example, said at least one surfactant has a HLB value ranging between 2 and 10, or between 2 and 9; with preference between 3 and 8. The HLB value is the value of hydrophilic-lipophilic balance according to the Griffin’s method (1954). For example, said at least one surfactant is selected from lecithin and / or polyglycerol polyricinoleate; with preference, said at least one surfactant is lecithin. The presence of the surfactant plasticizes the surface of the microstructure.

[0086] When the one or more components act as one or more active biological ingredients, such as one or more active pharmaceutical ingredients, the lignin microsphere of the present disclosure can be used in relase application.

[0087] The process to make a suspension of the lignin microsphere is remarkable in that it comprises the following steps: a) providing lignin, b) providing a first type of one or more solvents; c) mixing the first type of one or more solvents provided at step (b) and the lignin provided at step (a) to form a first mixture; d) fractionating, preferably centrifugating, the first mixture formed at step (c), so as to recover at least a first soluble fraction of the lignin in said first type of one or more solvents; f) preparing a solution of one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into said first type of one or more solvents; g) mixing the solution prepared at step (f) with the first soluble fraction of the lignin recovered at step (d), so as to form a second mixture, said second mixture comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents; h) providing one or more liquids immiscible with the first type of one or more solvents provided at step (b); said one or more liquids being for example selected from the group comprising one or more natural oils, one or more synthetic oils, one or more aprotic polar solvents or a mixture thereof; i) adding the second mixture formed at step (g) into the one or more liquids provided at step (h) so as to form an emulsion comprising the second mixture; the emulsion being in the one or more liquids provided at step (h), j) evaporating the first type of one or more solvents, so as to form a suspension in the one or more liquids provided at step (h) of lignin microsphere; wherein said first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) is at least partially soluble in said first type of one or more solvents.

[0088] Advantageously, the first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) has a solubilty of at least 10% as determined by a solubility test A into said first type of one or more solvents, namely ranging between 10% and 100% as determined by a solubility test A, or between 15% and 90%, or between 20% and 80%.

[0089] For example, the first type of one or more solvents provided at step (b) is selected from the group comprising acetone, methanol, ethanol, 1 -propanol, iso-propanol, 1 -butanol, ethylene glycol, ethyl acetate, ethyl lactate, iso-propyl acetate, tetrahydrofuran, 2- methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof, more preferably ethanol and / or iso-propanol; even more preferably ethanol.

[0090] For example, the step (c) of mixing is performed using a vortex mixer.

[0091] For example, the step (d) of fractionating is performed by centrifugating or by filtration, preferably by centrifugating. In case the step (d) is performed by filtration, a metallic sieve filter can be used. For example, when the step (d) of fractionating is performed by centrifugating, the centrifugation is performed at room temperature, namely at a temperature ranging between 15°C and 30°C, or preferably ranging between 20°C and 25°C.

[0092] For example, when the step (d) of fractionating is performed by centrifugating, the centrifugation is performed with a relative centrifugal force ranging between 100 g and 2000 g, preferably between 200 g and 1800 g, more preferably between 500 g and 1500 g.

[0093] For example, when the step (d) of fractionating is performed by centrifugating, the centrifugation is performed for a time comprised between 1 minute and 15 minutes, preferably between 2 minutes and 14 minutes, or between 3 minutes and 10 minutes.

[0094] With preference, the second mixture formed at step (g) comprises one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates at a concentration ranging between 0.1 % and 30 % of the lignin concentration in the first soluble fraction of the lignin, more preferably between 0.5 % and 25 %, even more preferably between 1 % and 20%. For example, the first soluble fraction recovered at step (d) comprises lignin at a concentration ranging between 1 mg / ml and 100 mg / ml of the first type of one or more solvents as determined by gravimetric analysis, preferably between 5 mg / ml and 95 mg / ml, more preferably between 10 mg / ml and 90 mg / ml, even more preferably between 15 mg / ml and 85 mg / ml, most preferably between 20 mg / ml and 80 mg / ml.

[0095] Advantageously, when the one or more liquids provided at step (h) are mixed with the first type of one or more solvents provided at step (b) to form a first liquid pair, the absorbance of the first liqud pair is superior than 0.05 AU as determined by a solublity test B, preferably superior than 0.06 AU, more preferably superior than 0.07 AU.

[0096] The one or more liquids provided at step (h) can thus be selected from the group comprising one or more natural oils (such as camelia seed oil and / or rapeseed oil), one or more synthetic oils (such as silicone oil and / or polyalkylene glycol oil), one or more mineral oils, one or more aprotic polar solvents (such as dichloromethane and / or dimethylformamide) or a mixture thereof. During formation of the microspheres, the second mixture formed at step (g) and comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents is added and / or poured into the one or more liquids provided at step (h). A liquid is then dispersed into another liquids (for example, ethanol and / or / so-propanol is dispersed into a natural oil) and upon evaporation of the dispersed liquid, namely during the course of step (j), a suspension will be formed.

[0097] In a second preferred embodiment, alternative to the first embodiment, the lignin microstructure is a lignin microcapsule (see figure 2). Such microcapsule is hollow, and can be filled with air and / or any liquids.

[0098] Such lignin microcapsules have a diameter D and the size of the thickness of the outer layer is ranging below 25% of the diameter D as determined by scanning electron microscopy, preferably below 20% or below 15%, or below 10%. With preference, the size of the thickness of the outer layer is ranging between 1 % and 10% of the diameter D as determined by scanning electron microscopy. Advantageously, the lignin microstructure shows a volume V and further presents one or more internal voids which have a volume of at least 50% of the volume of the lignin microstructure, as evidenced by scanning electron microscopy, more preferably of at least 55%, even more preferably of at least 60%.

[0099] When the one or more components act as one or more active biological ingredients, such as one or more active pharmaceutical ingredients, the lignin microcapsule of the present disclosure can be used in relase application.

[0100] The process to make a suspension of the lignin microcapsule is remarkable in that it comprises the following steps: a) providing lignin, b) providing a first type of one or more solvents; c) mixing the first type of one or more solvents provided at step (b) and the lignin provided at step (a) to form a first mixture; d) fractionating, preferably centrifugating, the first mixture formed at step (c), so as to recover at least a first soluble fraction of the lignin in said first type of one or more solvents; e) recovering a precipate at step (d) and washing said precipitate with a second type of one or more solvents, so as to recover a second soluble fraction of the lignin in said second type of one or more solvents; f) preparing a solution of one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into said first type of one or more solvents; g) mixing the solution prepared at step (f) with the second soluble fraction of the lignin recovered at step (e), so as to form a third mixture; said third mixture comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents and the second type of one or more solvents; h) providing one or more liquids immiscible with the first type of one or more solvents provided at step (b); said one or more liquids being miscible with the second type of one or more solvents used at step (e); said one or more liquids being for example selected from the group comprising one or more natural oils, one or more synthetic oils, one or more aprotic polar solvents or a mixture thereof; i) adding dropwise the third mixture formed at step (g) into the one or more liquids provided at step (h) so as to form an emulsion comprising the third mixture; the emulsion being in the one or more liquids provided at step (h), j) evaporating the first type of one or more solvents and the second type of one or more solvents, so as to form a suspension in the one or more liquids provided at step (h) of lignin microcapsule; wherein said first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) is at least partially soluble in said first type of one or more solvents and wherein said second type of one or more solvents is different than the first type of one or more solvents.

[0101] Advantageously, the first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) has a solubilty of at least 10% as determined by a solubility test A into said first type of one or more solvents, namely ranging between 10% and 100% as determined by a solubility test A, or between 15% and 90%, or between 20% and 80%. For example, the first type of one or more solvents provided at step (b) is selected from the group comprising acetone, methanol, ethanol, 1 -propanol, iso-propanol, 1 -butanol, ethylene glycol, ethyl acetate, ethyl lactate, iso-propyl acetate, tetrahydrofuran, 2- methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof.

[0102] For example, the step (c) of mixing is performed using a vortex mixer.

[0103] For example, the step (d) of fractionating is performed by centrifugating or by filtration, preferably by centrifugating. In case the step (d) is performed by filtration, a metallic sieve filter can be used.

[0104] For example, when the step (d) of fractionating is performed by centrifugating, the centrifugation is performed at room temperature, namely at a temperature ranging between 15°C and 30°C, or preferably ranging between 20°C and 25°C.

[0105] For example, when the step (d) of fractionating is performed by centrifugating, the centrifugation is performed with a relative centrifugal force ranging between 100 g and 2000 g, preferably between 200 g and 1800 g, more preferably between 500 g and 1500 g.

[0106] For example, when the step (d) of fractionating is performed by centrifugating, the centrifugation is performed for a time comprised between 1 minute and 15 minutes, preferably between 2 minutes and 14 minutes, or between 3 minutes and 10 minutes.

[0107] For example, the step of washing the precipitate with a second type of one or more solvents during step (e) is performed by mixing the precipitate with the second type of one or more solvents, preferably by using a vortex mixer, followed by a step of performing a centrifugation of the mixture so obtained. Said centrifugation is performed with a relative centrifugal force ranging between between 100 g and 2000 g, preferably between 200 g and 1800 g, more preferably between 500 g and 1500 g; and / or at room temperature, namely at a temperature ranging between 15°C and 30°C, or preferably ranging between 20°C and 25°C; and / or for a time comprised between 1 minute and 15 minutes, preferably between 2 minutes and 14 minutes, or between 3 minutes and 10 minutes.

[0108] For example, the second type of one or more solvents used at step (e) is selected from the group comprising acetone, methanol, ethanol, 1 -propanol, iso-propanol, 1 -butanol, ethylene glycol, ethyl acetate, ethyl lactate, iso-propyl acetate, tetrahydrofuran, 2- methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof.

[0109] For example, the solution prepared at step (f) has a concentration of the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents ranging between 1 mg / ml and 100 mg / ml, preferably between 2 mg / ml and 50 mg / ml, more preferably between 3 mg / min and 25 mg / ml. The one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates are for example solubilized into the first type of one or more solvents preferably using a vortex mixer, and / or by sonication, and / or by centrifugation, and / or by a combination thereof. For example, the sonication is performed for a time ranging between 1 minute and 10 minutes, or between 2 minutes and 5 minutes, and / or at a frequency ranging between 10 kHz and 50 kHz, or between 20 kHz and 40 kHz, and / or at room temperature, namely at a temperature ranging between 15°C and 30°C, or preferably ranging between 20°C and 25°C.

[0110] With preference, the third mixture formed at step (g) comprises one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates at a concentration ranging between 0.1 % and 30 % of the lignin concentration in the second soluble fraction of the lignin, more preferably between 0.5 % and 25 %, even more preferably between 1 % and 20%. For example, the second soluble fraction recovered at step (e) comprises lignin at a concentration ranging between 1 mg / ml and 100 mg / ml of the second type of one or more solvents as determined by gravimetric analysis, preferably between 5 mg / ml and 95 mg / ml, more preferably between 10 mg / ml and 90 mg / ml, even more preferably between 15 mg / ml and 85 mg / ml, most preferably between 20 mg / ml and 80 mg / ml.

[0111] Advantageously, when the one or more liquids provided at step (h) are mixed with the first type of one or more solvents provided at step (b) to form a first liquid pair, the absorbance of the first liqud pair is superior than 0.05 AU as determined by a solublity preferably superior than 0.06 AU, more preferably superior than 0.07 AU. When the one or more liquids provided at step (h) are mixed with the second type of one or more solvents used at step (e) to form a second liquid pair, the absorbance of the second liquid pair is lower or equal to 0.05 AU as determined by a solubiity test B, preferably lower than 0.04 AU, more preferably lower than 0.03 AU.

[0112] The one or more liquids provided at step (h) can thus be selected from the group comprising one or more natural oils (such as camelia seed oil and / or rapeseed oil), one or more synthetic oils (such as silicone oil and / or polyalkylene glycol oil), one or more mineral oils, one or more aprotic polar solvents (such as dichloromethane and / or dimethylformamide) or a mixture thereof.

[0113] For example, the dropwise addition of step (i) is performed at an addition rate of the third mixture ranging between 500 pl / min and 5 ml / min, preferably between 750 pl / min and 3 ml / min, or between 900 pl / min and 2 ml / min.

[0114] For example, the dropwise addition of step (i) is performed while the one or more liquids provided at step (h) are stirred. With preference, the stirring is achieved at rate ranging between 1000 rpm and 2000 rpm, preferably between 1100 rpm and 1500 rpm.

[0115] For example, the step (j) of evapoarating is performed under vacuum, preferably at pressure ranging between 0.5 kPa and 5 kPa, or between 0.7 kPa and 3 kPa, or between 0.8 kPa and 2 kPa.

[0116] For example, the step (j) of evaporating is performed during a time ranging between 30 minutes and 3 hours, preferably between 1 hour and 2 hours.

[0117] For example, the step (j) of evaporating is performed at a temperature ranging between 30°C and 70°C, preferably between 40°C and 60°C.

[0118] During formation of the microcapsules, the third mixture formed at step (g) and comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents and the second type of one or more solvents is added dropwise into the one or more liquids provided at step (h). Upon this drowise addition, an emusltion with the first type of one or more solvents is formed, because of the immisicibility of such first type of one or more sovlents. Then the lignin and the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates self assembled into nanoparticles on the surface of the dispersed droplets of the first type of one or more solvents.

[0119] That is the reason why upon preparation of the microcapsules, the combination of the first type of one or more solvents, which must be immisiclbe with the one or more liquids provided at step (h), with the second type of one or more solvents is important.

[0120] In one example, the first type of one or more solvents provided at step (b) is ethanol and the second type of one or more solvents used at step (e) is acetone. In another example, the first type of one or more solvents provided at step (b) is ethanol and the second type of one or more solvents sued at step (e) is 2-methyltetrahydrofuran. In yet another example, the first type of one or more solvents provided at step (b) is iso- propanol and the second type of one or more solvents used at step (e) is acetone. In still another example, the first type of one or more solvents provided at step (b) is iso- propanol and the second type of one or more solvents used at step (e) is 2- methyltetrahydrofuran.

[0121] It has been determined by liquid chromatography mass spectrometry analysis that the lignin microspheres or the lignin microcapsules of the present disclosure have an encapsulation efficiency of at least 60 wt.% based on the total weight of the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates provided at step (f), preferably of at least 70 wt.%, more preferably of at least 80 wt.%, even more preferably of at least 90 wt.%, most preferably of at least 95 wt.% or even 100 wt.%. That means that at least a large part or even the totality of the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates in the solution of the first type of one or more sovlents prepared at step (f) can end up into the outer layer of the lignin microstructure. 1

[0122] The suspension of the lignin microspheres or of the lignin microcapsules is thus in one or more liquids selected from the group comprising one or more natural oils, one or more synthetic oils, one or more aprotic polar solvents or a mixture thereof. This is a solvent-in-oil emulsion. With preference, said suspension comprises between 1 wt.% and 20 wt.% of the lignin microsphere based on the total weight of said solvent-in-oil emulsion, more preferably between 2 wt.% and 18 wt.%, even more preferably between 5 wt.% and 15 wt.%.

[0123] Once the suspension of the lignin microspheres or of the lignin microcapsules is obtained, it is also possible to performed a step (k) of separation of the lignin microspheres or of the lignin microcapsules from the one or more liquids provided at step (h). With preference, the step (k) is carried out by centrifugation and / or by filtration, preferably by using a metallic sieve filter. More preferably, the step (k) is carried out by centrifugation. For example, the step of centrifugation is performed with a relative centrifugal force ranging between 100 g and 2000 g, preferably between 200 g and 1800 g, more preferably between 500 g and 1500 g, and / or for a time ranging between 1 minute and 15 minutes, preferably between 2 minutes and 14 minutes, or between 3 minutes and 10 minutes. For example, the step of centrifugation is performed at room temperature, namely at a temperature ranging between 15°C and 30°C, or preferably ranging between 20°C and 25°C.

[0124] In order to remove the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates, once step (k) has been performed, it is possible to perform the step (m) of providing a third type of one or more solvents and the step (n) of washing, or digesting, the lignin microspheres or the lignin microcapsules. After this digestion, either lignin microspheres or lignin microcapsules with an outer layer consisting of or comprising porous lignin is obtained. In fact, such lignin microspheres or such lignin microcapsules have an outer layer made of porous lignin. They differ from the unwashed or undigested lignin microsphere by the presence of pores in the outer layer. The third type of one or more solvents is selected so that the components acting as one or more active biological ingredients and / or one or more sacrificial templates provided at step (f) are at least partially soluble into said third type one or more solvents. With preference, the third type of one or more solvents provided at step (m) is selected so that the components acting as one or more active biological ingredients and / or one or more sacrificial templates provided at step (f) have a solublity of at least 10% as determined by a solubilty test C into said third type of one or more solvents, namely ranging between 10% and 100% as determined by a solubility test C, or between 15% and 90%, or between 20% and 80%.

[0125] Depending the degree of solubility of the one or more active biological ingredients and / or one or more sacrificial templates into said third type of one or more solvents, it is possible to achieve different degree of porosity on the outer layer of either the lignin microsphere or the lignin microcapsule.

[0126] For example, when microcapsules loaded with madecassoside are washed with iso- propanol (figure 3), they yield larger pores than when washed with ethyl acetate (figure 4), since the former is a better solvent for madecassoside.

[0127] For example, the third type of one or more solvents provided at step (m) is selected from the group comprising acetone, methanol, ethanol, 1 -propanol, / so-propanol, 1- butanol, ethylene glycol, ethyl acetate, ethyl lactate, / so-propyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof.

[0128] Such lignin microspheres or lignin microcapsules, having an outer layer consisting of or comprising porous lignin, can be used as hydrophilic carrier system.

[0129] Starting from the suspension of the lignin microspheres or of the lignin microcapsules, it is possible to perform the step (I) of adding one or more gelling agents into the suspension formed at step (j). It is understood here that no separation step (k) is carried out after step (j) to form the organogel. However, if a separation step (k) is nevertheless carried out, it can be possible to remake the suspension of the lignin microspheres or of the lignin microcapsules into the one or more liquids such as those provided at step (h) before performing the step (I) of adding the one or more gelling agents. For example, the one or more gelling agents can comprise a mixture of castor oil and caprylic capric triglycerides (such as EstoGel®, commercially avalaible at Polymerexpert). Another example could be a linear triblock copolymer based on styrene and ethylene / butene (such as Kraton™ A1536 H Polymer) or a linear triblock copolymer based on styrene ethylene butene styrene (such as Kraton™ G-1650). Then, an organogel comprising the suspension of the lignin microspheres, or an organogel comprising the suspension of lignin microcapsule, and further comprising one or more gelling agents can be obtained. With preference, said organogel comprises between 1 wt.% and 20 wt.% of one or more gelling agents based on the total weight of said organogel, more preferably between 2 wt.% and 18 wt.%, even more preferably between 5 wt.% and 15 wt.%.

[0130] TEST AND DETERMINATION METHODS

[0131] Solubility test A to determine the solubiity of lignin provided at step (a) into the one or more solvents, namely into the first type of one or more solvents and / or into the second type of one or more solvents.

[0132] For its part, the solubility is measured according to the solubility test A, which comprises the following method:

[0133] 1 ) taking a weight of test sample (wtest sample), for example 40 g of lignin, this weight being expressed as dry weight;

[0134] 2) dispersing this weight in 200 ml of said one or more solvents at room temperature in an borosilicate bottle and stirring vividly for 5 minutes;

[0135] 3) centrifuging the suspensions to separate the soluble and insoluble fractions;

[0136] 4) filtering the soluble fraction (supernatant) with a common laboratory paper filter, for example of Whatman® 8-13 pm;

[0137] 5) pipetting 5 ml of filtrate and introducing this amount into a dry and fared crystallizing dish; allowing the majority of the solvent to evaporate at the hood then placing the crystallization dish containing the wet product for vacuum drying for 12 hours at 40°C for acetone and ethanol; for solvents with lower volatility the temperature of drying is adjusted accordingly;

[0138] 6) after cooling in a desiccator, weighing the weight of lignin obtained after drying (Wsolids extract).

[0139] The solubility is calculated in the following way:

[0140] Solubility (%)=(Csolids extract / Ctest sample)*100

[0141] Ctest sample = 40 g / 200 ml = 200 mg / ml

[0142] Csoiids extract = mass solids extract I 5 ml mass solids extracts = mass of dish containing dry solids extract - tare mass of dish Solubility test B to determine the degree of immiscibility of one or more liquids provided at step (h) with the solvents tested in solubility test A.

[0143] For its part, the solubility is measured according to the solubility test B, which comprises the following method:

[0144] 1 ) into a borosilicate vial taking a volume of test sample (Vtest sample), for example 9 ml of camelia seed oil;

[0145] 2) adding into this volume obtained in (1 ) a volume of one or more solvents so that volume ratio between the one or more liquids provided at step (h) and the one or more solvents is 90 / 10, for example in the present case, 1 ml of the first type of one or more solvents, for example ethanol,

[0146] 3) vortexing the vial for 5 minutes and / or emulsifying for 2 minutes;

[0147] 4) performing a turbidity measurement of the mixture with a spectrophotometer in the visible range;

[0148] 5) if the absorbance reading is above 0.05 AU then the liquids pair is defined as immiscible; and if the absorbance reading is below or equal to 0.05 AU , then the liquids pair is defined as miscible.

[0149] Spectrophotometer used to achieve the solublity test B

[0150] The miscibility test was performed with a Tecan Infinite M1000 PRO operating in single wavelength absorbance mode (A = 580 nm). The beam was blanked with pure solvent or liquid before the mixing and / or emulsification of the second solvent or liquid.

[0151] Solubility test C to determine determine the degree of solubility of the one or more components acting as active ingredients and / or sacrificial templates with the one or more solvents tested in the solubility test A.

[0152] For its part, the solubility is measured according to the solubility test C, which comprises the following method:

[0153] 1 ) taking a weight of test sample (wtest sample), for example 10 mg of madecassoside, this weight being expressed as dry weight;

[0154] 2) into a borosilicate vial dispersing this weight in 1 ml of said one or more solvents and shaking vividly for 5 minutes at room temperature;

[0155] 3) centrifuging the suspensions to separate the soluble and insoluble fractions; 4) decanting the one or more solvents;

[0156] 5) washing the precipitate with toluene;

[0157] 6) transferring said toluene suspension into a dry and fared crystallizing dish; allowing the majority of the toluene to evaporate at the hood then placing the crystallization dish containing the wet product for vacuum drying for 12 hours at 40°C for toluene;

[0158] 6) after cooling in a desiccator, weighing the weight of madecassoside for example obtained after drying (wsoiids).

[0159] The solubility is calculated in the following way:

[0160] Solubility % — (1 — (Wsoiids / Wtest sample)) 100 %

[0161] Scanning electron microscopy (SEM)

[0162] Scanning Electron Microscopy (SEM) was performed on a FEI Helios Nanolab 650 field emission SEM (FEI Europe B.V.) operating with an accelerating voltage of 2 kV and an emission current of 25 pA. Secondary electrons (SE) were collected with the through-the-lens detector. The samples are prepared as followed: a drop of solution is deposited on carbon coated copper grid and left to dry. The samples must be analysed right after drying, to avoid contamination by air moisture. Measurements were done in immersion mode.

[0163] Liquid Chromatography - Mass Spectrometry (LC-MS)

[0164] LC-MS / MS analysis was performed using a Thermo Ultimate 3000 HPLC system coupled with a Thermo linear trap quadrupole (LTQ)ZOrbitrap Elite high-resolution mass spectrometer equipped with a heated electrospray ionisation interface (ThermoFisher Scientific, USA). The injected sample volume was 5 pL. Mobile phases used for the separation of madecassoside are water (+ 0.1 % formic acid) and acetonitrile (+ 0.1 % formic acid) at a 75.5:24.5 ratio and 0.500 mL / min flow rate. Mass spectra were recorded in the 350-1200 m / z range in positive ion mode and the [M+H]+ ion at m / z 975.5159 was monitored for the quantification of madecassoside.

[0165] Gel permeation chromatography (GPC)

[0166] Gel permeation chromatography (GPC) is a type of size exclusion chromatography (SEC), where a sample is separated into its constituent parts based on their molecular sizes. This is accomplished by dissolving the sample in a mobile phase (solvent) and passing it through a porous column packing. The dried sample of lignin was dissolved in a dimethylformamide (DMF)ZLiBr (0.01 M) mixture to a concentration of 0.5 mg / ml.

[0167] The measurement was performed on a PL-GPC 50 Plus, Integrated GPC System from Polymer Laboratories (A Varian Inc. Company) equipped with a detection system comprising a refractive index (Rl) and Ultraviolet (UV) detector. The UV measurement was performed at a wavelength of 280 nm, which is generally associated with lignin. The system was equipped with two Agilent PolarGel-M (300x7.5mm) columns. The mobile phase was a DMF / LiBr (0.01 M) mixture; the sample was injected via a PL-AS RT GPC Autosampler at a flow rate of 0.5 ml / min. The sample was analysed using the software Cirrus GPC Version 3.2. P. All the results obtained were baseline corrected.

[0168] Tridimentional representation of lignin microsphere and of lignin microcapsule

[0169] The representations (see figures 1 and 2) were designed using the open-source 3D software Blender.

[0170] EXAMPLES

[0171] The embodiments of the present disclosure will be better understood by looking at the example below.

[0172] Lignin microsphere i) Weigh 40 g of Lignin D and add in 250 ml Duran bottle. ii) In the 250 ml Duran bottle containing the lignin, add 200 ml of analytical grade ethanol and manually shake vigorously for 2 minutes. While keeping the material suspended, split the content in four 50 ml PP Falcon tubes and place for vigorous vortexing at the Heidolph Reax vortex-shaker for another 3 minutes. iii) Place the tubes for centrifugation at 5k for 5 minutes at the Sigma 3-30KS centrifuge at 20 °C. Carefully decant the supernatant in 250 ml Duran bottle using a paper filter cone to avoid contamination from leached precipitated solids. This solution is the “unconcentrated Lignin D ethanol fraction” and is kept aside in the dark at room temperature for further manipulation. v) The unconcentrated Lignin D ethanol fraction is condensed down to approximately 100 ml at the rotary in order to obtain the “Lignin D ethanol stock solution”. An aliquot of 2 ml is drawn from the stock and added in a heat-gun dried, pre-weighted scintillation vial. The ethanol is left to evaporate at the hood overnight, followed by vacuum drying at 40 °C for 2 hours.

[0173] After the gravimetric evaluation of the concentration of the Lignin D ethanol stock solution, an appropriate volume is drawn for the preparation of 10 ml of 20 mg / ml Lignin D solution in ethanol. This solution is the lignin feed ethanol solution.

[0174] In a 250 ml 2-neck round bottom flask, 26 ml of freshly prepared lignin solution in ethanol (C = 26.24 mg / ml), 9 ml of ascorbic acid solution in ethanol (C ~ 10 mg / ml) and 35 ml of camellia oil saturated in lecithin were added. A PTFE centrifugal 8 mm stirring paddle was fitted to the flask using a 24 / 29 joint vacuum compatible adapter (BOLA) and the flask was connected to a programmable vacuum pump via the remaining 14 / 20 port. The biphasic mixture was emulsified at 700 rpm using an overhead stirrer for 10:00 at room temperature, then the flask was placed in an oil bath at 40°C, still under stirring at 700 rpm. Upon temperature equilibration, a stepwise vacuum gradient was applied, after which the stirring was interrupted (30:00, 100 mbar -> 15:00, 60 mbar -> 15:00, 40 mbar -> 15:00, 20 mbar -> 15:00, 10 mbar -> 10:00, 2 mbar. Total: 1 h40m). The mass loading of ascorbic acid in the lignin microsphere is 11.6 wt..% as determined by liquid chromatography mass spectrometry analysis.

[0175] In order to demonstrate the incorporation of the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates, a lignin microsphere was synthesized in accordance with the above protocol, except that ascorbic acid was not added, so as to generate a control microsphere.

[0176] Upon washing experiment with toluene of the lignin microsphere loaded with ascorbic acid, no alteration of the external structure of the lignin microstructure was observed (see figure 5). The cross-section image obtained by FIB reveals that the lignin microsphere has an homogeneous core (which is not hollow), and that the outer layer is non porous, since toluene was not able to solubilize ascorbic acid in a way to remove it.

[0177] The figure 6 is a FIB image of a lignin microsphere loaded with ascorbic acid that has been washed with / so-propanol, with an enlargement confirming that the lignin microstructure in question is not hollow due to a solid matrix and is thus a lignin microsphere. It can be seen that the solid matrix has internal voids, but that the major part of the solid matrix has no such internal voids.

[0178] Lignin microcapsule i) Weigh 40 g of Lignin D and add in 250 ml Duran bottle. ii) In the 250 ml Duran bottle containing the lignin, add 200 ml of analytical grade ethanol and manually shake vigorously for 2 minutes. While keeping the material suspended, split the content in four 50 ml PP Falcon tubes and place for vigorous vortexing at the Heidolph Reax vortex-shaker for another 3 minutes. iii) Place the tubes for centrifugation at 5k for 5 minutes at the Sigma 3-30KS centrifuge at 20 °C. Carefully decant the supernatant in 250 ml Duran bottle using a paper filter cone to avoid contamination from leached precipitated solids. This solution is the “unconcentrated Lignin D ethanol fraction” and is kept aside in the dark at room temperature for further manipulation. iv) In each of the Falcon tubes containing the precipitated the solid lignin cake after ethanol wash, 50 ml of analytical grade acetone is added (200 ml in total) and the tubes are shaken according to step ii), followed by centrifugation according to step iii). After decanting according to step iii), the supernatant is collected in a 250 ml Duran and this solution is the “unconcentrated Lignin D acetone fraction”. v) The unconcentrated Lignin D acetone fraction is condensed down to approximately 100 ml at the rotary in order to obtain the “Lignin D acetone stock solution”. The evaporated acetone can be recycled at this stage. An aliquot of 2 ml is drawn from the stock and added in a heat-gun dried, pre-weighted scintillation vial. The acetone is left to evaporate at the hood overnight, followed by vacuum drying at 40 °C for 2 hours. After the gravimetric evaluation of the concentration of the Lignin D acetone stock solution, an appropriate volume is drawn for the preparation of 10 ml of 20 mg / ml Lignin D solution in acetone. This solution is the lignin feed acetone solution. vi) In a 15 ml PP Falcon tube, 100 mg of madecassoside are added followed by 10 ml of analytical grade ethanol. The solution is vortexed for 2 minutes at high speed, sonicated for 2 minutes at 37 kHz I 100% at the Elmasonic ultrasonic bath at room temperature, and finally centrifuged at 5k for 5 minutes at the Sigma 3-30KS. The madecassoside dissolution is near-quantitative (>95%). The supernatant solution is the madecassoside feed ethanol solution. vii) The lignin and madecassoside feed solutions are combined and loaded in a 20 ml PP Braun syringe equipped with a long steel 21 G needle, then fitted to an Aladdin syringe pump programmed at 1 ml / min feed. viii) 166.7 g of camelia seed oil are weighed in a 250 ml Duran bottle fitted with a hollow 8 mm stirrer shaft cap and tubing inlet. ix) A Radleys 8 mm Teflon centrifugal stirring paddle is introduced in the Duran bottle containing the oil, then a Heidolph HEI-Torque Precision 400 overhead stirrer is fitted, and 1200 rpm are applied. The needle is fitted accordingly in the Duran bottle, for the solution to be injected close to the vortex. This is thought to enhance the diffusivity of the solvents, promote rapid solvent exchange and efficient solvent shifting. x) The process is initiated with the syringe pump injection of the feed in the stirred oil. Upon completion of the addition, in the Duran bottle containing the crude madeccasoside loaded lignin microspheres, a cross-shaped Teflon magnetic stirrer is added, and a vacuum compatible cap is fitted. xi) The bottle is placed on a stirrer hot plate equipped with a thermostated oil bath at 50 °C, and gradual vacuum is applied under stirring for the removal of the volatile species, ethanol and acetone. When the base vacuum of 1 kPa after 1 h20m is reached the bottle is removed, the content is split into four 50 ml PP Falcon tubes and centrifuged at 2.5k RCF for 5 minutes. The Falcons are decanted, and the supernatant oil is kept aside for further manipulation. The madecassoside loaded lignin microcapsules pellet is the final pure product. The mass loading of madecassoside in the lignin microcapsules is 33.3 wt..% as determined by liquid chromatography mass spectrometry analysis.

[0179] In order to demonstrate the incorporation of the one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates, a lignin microcapsule was synthesized in accordance with the above protocol, except that madecassoside was not added (not step vi as above), so as to generate a control microcapsule.

[0180] Upon washing experiment with toluene of the lignin microcapsule loaded with madecassoside (figures 7 and 9) and with the control microcapsule (figures 8 and 10), no alteration of the external structure of the lignin microstructure was observed in both cases. However, upon washing experiments with / so-propanol, the presence of pores was detected on the outer layer of the lignin microstructure that was obtained from the lignin microcapsule loaded with madecassoside (figures 11 and 13), while no alteration of the external structure of the control microcapsule was noticed (see figures 12 and 14).

[0181] It demonstrates therefore that toluene does not solubilize madecassoside, while / so- propanol does it and allows then to produce lignin microcapsule with an outer layer being porous.

[0182] Figures 15 (washing experiment with / so-propanol of the loaded lignin microcapsule) and 16 (washing experiment with / so-propanol of the unloaded lignin microcapsule, namely of the control lignin microcapsule) are a better view of the samples corresponding respectively to figures 13 and 14.

[0183] Figure 17 shows a cross-section of lignin microcapsule loaded with madecassoside that have been washed with toluene. As toluene has been used as the third type of solvents, no effect on the outer layer has been observed, since madecassoide is not soluble in toluene. However, the cross-section reveals that the lignin microcapsule is hollow.

[0184] Figure 18 shows a FIB image of lignin microcapsule loaded with madecassoside that has been washed with / so-propanol (scale of 4 pm) with an enlargement of the outer layer comprising porous lignin. On this image, the lignin microcapsule is hollow and presents an outer layer that is made of porous lignin.

[0185] Use of the madecassoside loaded lignin microcapsules in a release experiment

[0186] A prescribed amount of dry microsphere or microcapsule material loaded with active ingredient and / or sacrificial template was dispersed in 1x PBS buffer solution at room temperature under stirring to achieve a dispersion with concentration 0.1 mg / ml. Aliquots were drawn at regular intervals and were filtered using syringe membrane filtration. The concentration of the filtrates containing the dissolved active ingredients and / or sacrificial templates were determined with LC-MS.

[0187] Figure 19 is the scanning electron microscopy image of the loaded lignin microcapsules. The chemical structure of madecassoside has been represented and arrows indicate its release.

[0188] Figure 20 shows that there is up to 65% of release of the loaded mass of madecassoside from the lignin microcapsules in water.

Claims

CLAIMS1 . Lignin microstructure characterized in that the lignin microstructure presents an outer layer being a nanocomposite structure comprising lignin and one or more components comprising one or more active biological ingredients and / or one or more sacrificial templates, and in that said lignin microstructure further presents one or more internal voids as evidenced by scanning electron microscopy, wherein said lignin microstructure is a lignin microsphere or a lignin microcapsule.

2. Lignin microstructure according to claim 1 , characterized in that said one or more internal voids are at least partially filled with one or more fluids.

3. Lignin microstructure according to claim 1 or 2, characterized in that the outer layer is non-porous.

4. Lignin microstructure according to any one of claims 1 to 3, characterized in that the lignin of the lignin microstructure is selected from Kraft lignin, soda lignin, lignosulfonate lignin, organosolv lignin, enzymatically hydrolyzed lignin, mechanically extracted lignin or a combination thereof.

5. Lignin microstructure according to any one of claims 1 to 4, characterized in that the one or more components within the outer layer are in an amount ranging between 0.1 wt.% and 40 wt.% of the total weight of the lignin microstructure, as determined by liquid chromatography mass spectrometry analysis.

6. Lignin microstructure according to any one of claims 1 to 5, characterized in that the one or more components within the outer layer have a molecular mass ranging between 100 g / mol and 50000 100 g / mol.

7. Lignin microstructure according to any one of claims 1 to 6, characterized in that the one or more components within the outer layer are one or more hydrophilic components.

8. Lignin microstructure according to any one of claims 1 to 7, characterized in that the lignin microstructure shows a diameter D ranging between 500 nm and 500 pm as determined by scanning electron microscopy.

9. Lignin microstructure according to any one of claims 1 to 8, wherein the lignin microstructure is a lignin microsphere, characterized in that the lignin microsphere shows a volume V and further presents one or more internal voids which have a volume inferior to 50% of the volume of the lignin microstructure, as evidenced by scanning electron microscopy, said one or more internal voids being dispersed into a solid matrix.

10. Lignin microstructurte according to claim 9, characterized in that the lignin microspere presents more than one internal void, and each of said internal voids is interconnected with each other.

11. Lignin microstructure according to claim 9 or 10, characterized in that the nanocomposite structure of the outer layer further presents at least one surfactant as evidenced by scanning electron microscopy.

12. Lignin microstructure according to any one of claims 1 to 8, wherein the lignin microstructure is a lignin microcapsule, characterized in that the lignin microcapsule shows a diameter D and wherein the size of the thickness of the outer layer is ranging below 25% of the diameter D as determined by scanning electron microscopy.

13. Lignin microstructure according to any one of claims 1 to 12, characterized in that the lignin microstructure shows a volume V and further presents one or more internal voids which have a volume of at least 50% of the volume of the lignin microstructure, as evidenced by scanning electron microscopy.

14. Suspension of lignin microstructure according to any one of claims 1 to 13 in one or more liquids selected from the group comprising one or more natural oils, one or more synthetic oils, one or more aprotic polar solvents or a mixture thereof.

15. Organogel characterized in that it comprises the suspension as defined in claim 14 and one or more gelling agents.

16. Process to make a suspension of lignin microstructure according to claim 14, wherein the lignin microstructure is a lignin microsphere, said process is characterized in that it comprises the following steps: a) providing lignin, b) providing a first type of one or more solvents; c) mixing the first type of one or more solvents provided at step (b) and the lignin provided at step (a) to form a first mixture; d) fractionating the first mixture formed at step (c), so as to recover at least a first soluble fraction of the lignin in said first type of one or more solvents; f) preparing a solution of one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into said first type of one or more solvents; g) mixing the solution prepared at step (f) with the first soluble fraction of the lignin recovered at step (d), so as to form a second mixture, said second mixture comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents; h) providing one or more liquids immiscible with the first type of one or more solvents provided at step (b); i) adding the second mixture formed at step (g) into the one or more liquids provided at step (h) so as to form an emulsion comprising the second mixture; the emulsion being in the one or more liquids provided at step (h), j) evaporating the first type of one or more solvents, so as to form a suspension in the one or more liquids provided at step (h) of a lignin microstructure being a lignin microsphere as defined in any one of claims 1 to 13; wherein said first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) is at least partially soluble in said first type of one or more solvents.

17. Process according to claim 16, characterized in that the first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) has a solubilty of at least 10% as determined by a solubility test A into said first type of one or more solvents.

18. Process according to claim 16 or 17, characterized in that when the one or more liquids provided at step (h) are mixed with the first type of one or more solvents provided at step (b) to form a first liquid pair, the absorbance of the first liqud pair is superior than 0.05 AU as determined by a solublity test B.

19. Process according to any one of claims 16 to 18, characterized in that the first type of one or more solvents provided at step (b) is selected from the group comprising acetone, methanol, ethanol, 1 -propanol, / so-propanol, 1 -butanol, ethylene glycol, ethyl acetate, ethyl lactate, / so-propyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof.

20. Process to make a lignin microstructure, wherein said lignin microstructure is a lignin microsphere, according to any one of claims 1 to 13, characterized in that it comprises the process to make a suspension as defined in any one of claims 16 to 19, followed by the step (k) of separating the lignin microsphere as defined in any one of claims 1 to 13 from the one or more liquids provided at step (h).21 . Process to obtain a lignin microsphere with an outer layer consisting of porous lignin, said process comprising the process as defined in claim 20, followed by the step (m) of providing a third type of one or more solvents and the step (n) of washing the lignin microstructure being a lignin microsphere as defined in any one of claims 1 to 13 with the third type of one or more solvents provided at step (m), so as to obtain a lignin microsphere with an outer layer consisting of porous lignin, wherein the third type of one or more solvents are selected so that the components acting as one or more active biological ingredients and / or one or more sacrificial templates provided at step (f) are at least partially soluble into said third type one or more solvents.

22. Process according to claim 21 , characterized in that the third type of one or more solvents provided at step (m) is selected so that the components acting as one or more active biological ingredients and / or one or more sacrificial templates provided at step (f) have a solublity of at least 10% as determined by a solubilty test C into said third type of one or more solvents.

23. Use of the lignin microstructure being a lignin microsphere as defined in any one of claims 1 to 13, wherein the one or more components act as one or more active biological ingredients, in release application.

24. Use of a lignin microsphere with an outer layer consisting of porous lignin as produced by the process defined in claim 21 or 22 as hydrophilic carrier system.

25. Process to make a suspension of lignin microstructure according to claim 14, wherein the lignin microstructure is a lignin microcapsule, said process is characterized in that it comprises the following steps a) providing lignin, b) providing a first type of one or more solvents; c) mixing the first type of one or more solvents provided at step (b) and the lignin provided at step (a) to form a first mixture; d) fractionating the first mixture formed at step (c), so as to recover at least a first soluble fraction of the lignin in said first type of one or more solvents; e) recovering a precipate at step (d) and washing said precipitate with a second type of one or more solvents, so as to recover a second soluble fraction of the lignin in said second type of one or more solvents; f) preparing a solution of one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into said first type of one or more solvents; g) mixing the solution prepared at step (f) with the second soluble fraction of the lignin recovered at step (e), so as to form a third mixture; said third mixture comprising lignin and one or more components acting as one or more active biological ingredients and / or one or more sacrificial templates into the first type of one or more solvents and the second type of one or more solvents;h) providing one or more liquids immiscible with the first type of one or more solvents provided at step (b); said one or more liquids being miscible with the second type of one or more solvents used at step (e); i) adding dropwise the third mixture formed at step (g) into the one or more liquids provided at step (h) so as to form an emulsion comprising the third mixture; the emulsion being in the one or more liquids provided at step (h), j) evaporating the first type of one or more solvents and the second type of one or more solvents, so as to form a suspension in the one or more liquids provided at step (h) of a lignin microstructure being a lignin microcapsule as defined in any of claims 1 to 13; wherein said first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) is at least partially soluble in said first type of one or more solvents and wherein said second type of one or more solvents is different than the first type of one or more solvents.

26. Process according to claim 25, characterized in that the first type of one or more solvents provided at step (b) is selected so that the lignin provided at step (a) has a solubilty of at least 10% as determined by a solubility test A into said first type of one or more solvents.

27. Process according to claim 25 or 26, characterized in that when the one or more liquids provided at step (h) are mixed with the first type of one or more solvents provided at step (b) to form a first liquid pair, the absorbance of the first liqud pair is superior than 0.05 AU as determined by a solublity test B.

28. Process according to any one of claims 25 to 27, characterized in that when the one or more liquids provided at step (h) are mixed with the second type of one or more solvents used at step (e) to form a second liquid pair, the absorbance of the second liquid pair is lower or equal to 0.05 AU as determined by a solubiity test B.

29. Process according to any one of claims 25 to 28, characterized in that the first type of one or more solvents provided at step (b) is selected from the group comprising acetone, methanol, ethanol, 1 -propanol, / so-propanol, 1 -butanol,ethylene glycol, ethyl acetate, ethyl lactate, / so-propyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof.

30. Process according to any one of claims 25 to 29, characterized in tha the second type of one or more solvents used at step (e) is selected from the group comprising acetone, methanol, ethanol, 1 -propanol, / so-propanol, 1 -butanol, ethylene glycol, ethyl acetate, ethyl lactate, / so-propyl acetate, tetrahydrofuran, 2-methyltetrahydrofuran, one or more deep eutectic solvents, one or more ionic liquids, water or a combination thereof.31 . Process to make a lignin microstructure, wherein said lignin microstructure is a lignin microcapsule, according to any one of claims 1 to 13, characterized in that it comprises the process to make a suspension as defined in any one of claims 25 to 30, followed by the step (k) of separating the lignin microsphere as defined in any one of claims 1 to 13 from the one or more liquids provided at step (h).

32. Process to obtain a ligin microcapsule with an outer layer consisting of porous lignin, said process comprising the process as defined in claim 31 , followed by the step (m) of providing a third type of one or more solvents and the step (n) of washing the lignin microstructure being a lignin microcapsule as defined in any of claims 1 to 13 with the third type of one or more solvents provided at step (m), so as to obtain a ligin microcapsule with an outer layer consisting of porous lignin, wherein the third type of one or more solvents are selected so that the components acting as one or more active biological ingredients and / or one or more sacrificial templates provided at step (f) are at least partially soluble into said third type one or more solvents.

33. Process according to claim 31 , characterized in that the third type of one or more solvents provided at step (m) is selected so that the components acting as one or more active biological ingredients and / or one or more sacrificial templates provided at step (f) have a solublity of at least 10% as determined by a solubilty test C into said third type of one or more solvents.

34. Use of the lignin microstructure being a lignin microcapsule as defined in any one of claims 1 to 13, wherein the one or more components act as one or more active biological ingredients, in release application.

35. Use of a ligin microcapsule with an outer layer consisting of porous lignin as produced by the process defined in claims 32 or 33 as hydrophilic carrier system.

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