Biopolymer particles and their production

Abstract

The present disclosure provides a method for producing biopolymer particles. One embodiment provides a method comprising extruding a dispersed phase into an anti-solvent to form particles of a biopolymer, the dispersed phase comprising the biopolymer in a solvent. Another embodiment provides a method comprising passing the dispersed phase through a membrane to form an emulsion of the biopolymer in a continuous phase, thereby membrane emulsifying the dispersed phase in the continuous phase, and phase inverting with an anti-solvent to form particles of the biopolymer. In both embodiments, each of the solvent and the anti-solvent comprises water. Biopolymer particles obtained by the method are also provided.

Description

[Technical field]

[0001] The present disclosure relates generally to methods for making biopolymer particles, and in particular to methods for making biopolymer particles suitable for, but not limited to, applications in cosmetics, personal care, paints and coatings, packaging, construction, oil and gas, food, biomedical and pharmaceutical applications, and / or having improved environmental properties. The present invention also provides biopolymer particles obtainable by the methods of the present invention. [Background technology]

[0002] The development of biopolymers is important in reducing the environmental impact of consumer products. Polymeric materials are widely used due to their adaptability, durability and price, so much so that it is difficult to identify consumer products that do not contain polymeric materials. However, many of the synthetic polymers developed are mainly derived from oil and gas sources, which means that they are not compatible with the environment and rely on unsustainable resources. Polymer microparticles in particular cause serious environmental problems, as they often persist in the ecosystem even after the consumer discards the product. Biopolymers and biopolymer particles therefore play a major role in addressing these issues, as they are not only derived from renewable and sustainable raw materials, but are also often biodegradable. However, the production of biopolymer particles remains challenging, and some of the reagents typically used in their production are still associated with environmental and / or safety concerns.

[0003] One method that has been used to produce biopolymer particles is membrane emulsification followed by phase inversion. In the membrane emulsification process, the dispersed phase of the biopolymer is forced through the pores of a microporous membrane directly into the continuous phase to form an emulsion from which the particles can be extracted. The particles in the emulsion then undergo phase inversion, which includes exposing the emulsion to a poor solvent, for example by immersing the emulsion in the poor solvent. However, the solvents and poor solvents used in such processes typically contain compounds that may be unsuitable for producing particles for certain applications, for example due to safety concerns. For example, dimethyl sulfoxide (DMSO) can be used as a co-solvent with 1-ethyl-3-methylimidazolium acetate (EmimOAc) to directly dissolve cellulose, but DMSO is listed in Annex II of Regulation (EC) No. 1223 / 2009 on Cosmetics (available at https: / / echa.europa.eu / cosmetics-prohibited-substances). The use of such compounds may raise environmental concerns; for example, recycling of the solvent may be more difficult and costly, and the environmental benefits of the biopolymer particles may not be fully realized.

[0004] Overall, there remains a need in the art for a method for producing biopolymer particles that does not suffer from the problems described above, particularly a method that avoids the use of solvents and / or poor solvents that are undesirable, unsuitable or prohibited for use in certain applications and / or that negatively impact the overall environmental benefits of the biopolymer particles. The method of the present disclosure satisfies this unmet need. Summary of the Invention

[0005] In a first aspect, the present disclosure provides a method for producing biopolymer particles comprising extruding a dispersed phase into an anti-solvent to form particles of biopolymer, the dispersed phase comprising the biopolymer in a solvent, and each of the solvent and anti-solvent comprising water.

[0006] In a second aspect, the disclosure provides a method for producing biopolymer particles, comprising: (a) membrane emulsifying a dispersed phase in a continuous phase, the dispersed phase comprising said biopolymer in a solvent, by passing the dispersed phase through a membrane to form an emulsion of said biopolymer in the continuous phase; and (b) phase inversion with an anti-solvent to form particles of said biopolymer; each of the solvent and anti-solvent comprises water.

[0007] Features that overlap between the methods of the first and second aspects may be described herein with reference to one method, but those skilled in the art will appreciate that such descriptions are equally applicable to the other method, for example descriptions of the solvent and anti-solvent for the dispersed phase apply to each aspect, as well as to the biopolymer.

[0008] In a third aspect, the present disclosure provides biopolymer particles obtained by each of the methods described herein. Thus, the features described herein in relation to those methods are also applicable to the biopolymer particles obtained by the methods. The biopolymer particles obtained by the methods described herein can be distinguished from the prior art by using water in the solvent and anti-solvent during their production, thereby avoiding the presence of undesirable and / or prohibited compounds (e.g., DMSO) in the particles, which makes such particles suitable, for example, in cosmetics, and also reduces the environmental impact of the process of producing the particles. Furthermore, the use of water in the solvent can improve the yield of the method of the present disclosure and / or the regularity of the size and shape of the particles obtained.

[0009] In various embodiments of the first aspect, forming biopolymer particles by extruding the dispersed phase into an anti-solvent comprises extruding the dispersed phase through a fluid medium by capillary extrusion. Extrusion through a fluid medium may comprise extruding the dispersed phase into a mold and subsequently contacting the extruded dispersed phase with an anti-solvent. A mold may be used in conjunction with capillary extrusion.

[0010] In various embodiments of the first aspect, the extruded dispersed phase is dropped from a height of about 1 cm to about 80 cm from the surface of the poor solvent, preferably from a height of about 5 cm to about 70 cm from the surface of the poor solvent, and more preferably from a height of about 10 cm to about 60 cm from the surface of the poor solvent.

[0011] In various embodiments of the second aspect, prior to (b), the emulsion is cooled to a temperature T1, where T1 is the pour point of the continuous phase (T cont ) higher than the transition temperature (T disp ) or less, i.e., T cont <T1≦T disp said transition temperature being selected from the group consisting of freezing point, glass transition temperature and pour point; T disp >T cont For phase inversion (b), the anti-solvent can be further cooled to a temperature T2, where T2 is equal to T disp Lower, preferably T2 is equal to T1.

[0012] In various embodiments of any of the aspects of the disclosure, the biopolymer is a polysaccharide, and preferably, the biopolymer is cellulose. When the biopolymer is cellulose, the cellulose can be selected from the group consisting of virgin cellulose, recycled cellulose, pulp cellulose, and microcrystalline cellulose, and combinations thereof, and preferably, the biopolymer can be microcrystalline cellulose.

[0013] In various embodiments of any aspect of the present disclosure, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, preferably about 4% to about 10% by weight.

[0014] In various embodiments of any of the aspects of the present disclosure, the dispersed phase is prepared by adding the biopolymer to a solvent, which includes water prior to the addition of the biopolymer. Alternatively, in various embodiments of any of the aspects of the present disclosure, the dispersed phase is prepared by adding the biopolymer to a solvent, which includes water only after the addition of the biopolymer.

[0015] In various embodiments of any aspect of the present disclosure, the solvent of the dispersed phase comprises about 2% to about 12% by weight water, preferably about 4% to about 10% by weight water. In various embodiments of any aspect of the present disclosure, the solvent of the dispersed phase further comprises an ionic liquid. The ionic liquid may comprise 1-ethyl-3-methylimidazolium acetate.

[0016] In various embodiments of any aspect of the present disclosure, the anti-solvent is substantially free of organic solvents. The term "substantially free" is further defined herein. In various embodiments of any aspect of the present disclosure, the anti-solvent further comprises an ionic liquid. The ionic liquid may comprise 1-ethyl-3-methylimidazolium acetate.

[0017] In various embodiments of any aspect of the present disclosure, the ionic liquid is present in the anti-solvent at a concentration of up to about 50% by weight, preferably up to about 30% by weight. For example, the ionic liquid may be present in the anti-solvent at a concentration of about 0.001% to about 50% by weight, preferably about 0.001% to about 30% by weight. Further concentrations are described herein. Alternatively, in various embodiments of any aspect of the present disclosure, the anti-solvent consists of water.

[0018] In various embodiments of any aspect of the present disclosure, the temperature of the dispersed phase is from about 5°C to less than about 100°C, preferably from about 20°C to about 80°C, and more preferably from about 25°C to about 70°C.

[0019] In various embodiments of any aspect of the present disclosure, the temperature of the anti-solvent is from about 5°C to about 80°C, preferably from about 15°C to about 60°C.

[0020] In various embodiments of any aspect of the present disclosure, the biopolymer particles have a diameter of about 1 μm to about 500 μm. Alternatively, the biopolymer particles may have a diameter of about 0.2 mm to about 3 mm. In yet other embodiments, the biopolymer particles may have a diameter of about 1 mm to about 10 mm.

[0021] These aspects and embodiments are set out in the accompanying independent and dependent claims. It will be understood that features of the dependent claims may be combined with each other and with features of the independent claims in other combinations than those explicitly set out in the claims. Furthermore, the approach described herein is not limited to the specific embodiments set out below, but rather includes and contemplates any combination of features provided herein.

[0022] The above and other objects, features and advantages of the present disclosure will become more fully apparent hereinafter from a consideration of the following detailed description taken in conjunction with the accompanying drawings, in which: It is to be expressly understood, however, that the drawings are for illustrative purposes only and are not to be construed as defining the scope of the present disclosure. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of an embodiment of the first aspect of the present disclosure, in which the dispersed phase is extruded into an anti-solvent. [Diagram 2] FIG. 1 is a schematic diagram of membrane emulsification. [Diagram 3] This figure includes four photographs of particles showing an example of a particle with the desired shape (spherical) (Figure 3(a)) and examples of deformation and aggregation problems that can occur with traditional membrane emulsification methods (Figures 3(b)-3(d)). [Figure 4] FIG. 3(a) includes a schematic diagram of a conventional membrane emulsification process and a diagram of one embodiment of emulsion cooling according to a second aspect of the present disclosure (FIG. 4(b)). [Diagram 5]1 is an optical micrograph of a solution of microcrystalline cellulose (MCC) in EmimOAc, optionally with 8 wt% water present. Labels (a)-(g) refer to the following MCC solutions: a) 4 wt% MCC, b) 6 wt% MCC; c) 8 wt% MCC; d) 4 wt% MCC, 8 wt% water; e) 6 wt% MCC, 8 wt% water; f) 8 wt% MCC, 8 wt% water; g) control (8 wt% MCC in a 70:30 mixture of DMSO:EmimOAc). Preparation of these cellulose solutions and control is described in the Examples herein. [Figure 6] 5 shows an image of microcrystalline cellulose (MCC) beads / particles in a wet state after formation with 8 wt % water in accordance with an exemplary embodiment of the first aspect of the present disclosure compared to formation without water. The photograph is further labeled with the weight % of MCC (corresponding to the solution shown in FIG. 5) and the temperature of the dispersed phase, where RT means room temperature. The preparation of the beads / particles in a wet state is described in Example 2 herein. [Figure 7] 5 shows optical micrographs of dried microcrystalline cellulose (MCC) beads / particles obtained with 8 wt% water according to an exemplary embodiment of the first aspect of the present disclosure compared to beads / particles obtained without 8 wt% water. The optical micrographs are further labeled with the weight % of MCC (corresponding to the solution shown in FIG. 5) and the temperature of the dispersed phase, where RT means room temperature. The preparation of the dried beads / particles is described in Example 2 herein. [Figure 8] 1 shows images of wet microcrystalline cellulose beads / particles produced using an EmimOAc solution containing 8 wt. % MCC and 8 wt. % water and a heated syringe in an exemplary embodiment of the first aspect of the present disclosure. This embodiment is described in Example 3 herein. The MCC beads / particles are further characterized by the drop height (13 cm, 26 cm, or 39 cm) and the temperature of the syringe needle during extrusion. [Figure 9]8 shows optical micrographs of dried microcrystalline cellulose beads / particles produced using an EmimOAc solution containing 8 wt. % MCC and 8 wt. % water and a heated syringe in an exemplary embodiment of the first aspect of the present disclosure. This embodiment is described in Example 3 herein. As in FIG. 8, the MCC beads / particles are characterized by the drop height and the temperature of the syringe needle during extrusion. [Figure 10] 1 shows images of wet microcrystalline cellulose beads / particles produced using an EmimOAc solution containing 6 wt. % MCC and 8 wt. % water and a heated syringe in an exemplary embodiment of the first aspect of the present disclosure, which is described in Example 3 herein. The MCC beads / particles are further characterized by drop height and needle temperature during extrusion. [Figure 11] 1 shows optical micrographs of dried microcrystalline cellulose beads / particles produced using an EmimOAc solution containing 6 wt. % MCC and 8 wt. % water and a heated syringe in an exemplary embodiment of the first aspect of the present disclosure. This embodiment is described in Example 3 herein. The MCC beads / particles are further characterized by drop height and needle temperature during extrusion. [Figure 12] 1 is a graph of viscosity (Pa s) versus temperature (°C) for cellulose solutions (with or without 8 wt% water) prepared in the examples. Viscosity is measured at a shear rate of 1 s-1 as described herein. The dashed horizontal line at 1.89 Pa s indicates the viscosity of the control solution (8 wt% MCC in a 70:30 mixture of DMSO:EmimOAc at room / ambient temperature). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Although various exemplary embodiments are described or proposed herein, other exemplary embodiments utilizing various methods and materials similar or equivalent to those described or proposed herein are encompassed by the general inventive concept. Aspects and features of conventionally implemented embodiments may not be discussed or described in detail in the interest of brevity. Thus, it will be understood that aspects and features of the apparatus and methods described herein that are not described in detail may be implemented in accordance with any conventional techniques for implementing such aspects and features.

[0025] As used in this specification and the claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0026] As used herein, unless otherwise specified, the term "about" modifying the amount of an ingredient refers to variations in the numerical amount that may occur, for example, through typical measuring and handling procedures used to produce concentrates, mixtures or solutions in the real world; through inadvertent errors in these procedures; through differences in the manufacture, source or purity of materials used, or in the execution of the method. The term "about" also encompasses amounts that differ due to different equilibrium conditions for compositions resulting from a particular initial mixture. Whether or not modified by the term "about," the claims include the equivalent of the amount.

[0027] The ranges provided herein provide exemplary amounts of each component. Each of these ranges can be taken alone or combined with one or more of the other component ranges.

[0028] As used herein, the term "at least" includes the endpoints of the specified range, for example, "at least 10 cm" includes the value 10 cm.

[0029] As used herein, wt% means "weight percent" as a basis for calculating percentages. Unless otherwise stated, all % values ​​are calculated by weight and provided based on the total weight of the product in which the material is present. For example, the % of water in the solvent of the dispersed phase refers to the weight % of water based on the total weight of the solvent. Similarly, the % of biopolymer in the dispersed phase refers to the weight % of biopolymer based on the total weight of the dispersed phase.

[0030] As used herein, "substantially free" means no more than trace amounts, i.e., the amount of the relevant substance is negligible. In various embodiments, "substantially free" means no more than 1000 ppm of the relevant substance, preferably no more than 100 ppm, more preferably no more than 10 ppm, and even more preferably no more than 1 ppm.

[0031] The general inventive concept revolves around providing a method for producing biopolymer particles, which are suitable for use in, but not limited to, applications in cosmetics, personal care, paints and coatings, packaging, construction, oil and gas, food, biomedical and pharmaceutical applications, with improved environmental benefits. As well as being suitable for the above applications, the particles must also be produced with a reasonable yield, so that the method is commercially viable. Yield in the present disclosure refers to the mass of spherical particles or beads within a defined particle size distribution. Although spherical particles are particularly desirable, biopolymer particle production processes, particularly membrane emulsification processes, often suffer from problems with coalescence or aggregation, and even deformation, of the particles produced. Such mechanisms risk reducing the yield and therefore the commercial viability of the process. In extrusion processes, problems with coalescence and aggregation can occur, mainly due to the viscosity of the solution being extruded.

[0032] In a first aspect, the present disclosure provides a method for producing biopolymer particles, the method comprising extruding a dispersed phase into an anti-solvent to form particles of biopolymer. The dispersed phase comprises a biopolymer in a solvent, as further described below, and such extrusion of a dispersed phase is known in the art. It is a process in which the dispersed phase is forced, pressurized or extruded, for example, through a gap or an opening. The opening may be in a syringe, as shown in FIG. 1, or in any other suitable extrusion device known in the art.

[0033] A schematic diagram of an exemplary embodiment of the extrusion process of the present disclosure is shown in Figure 1. In the exemplary embodiment of Figure 1, a dispersed phase (1) comprising a biopolymer in a solvent is extruded through a needle (2) of a syringe (3). The extrusion is specifically carried out into an anti-solvent (4) to form biopolymer particles (5). In the exemplary embodiment of Figure 1, the extruded dispersed phase is dripped from a height d above the surface of the anti-solvent.

[0034] In a second aspect, the present disclosure provides a method for producing biopolymer particles, comprising a membrane emulsification step and a phase inversion step. Membrane emulsification is known in the art and is a technique in which a dispersed phase is forced through the pores of a microporous membrane directly into a continuous phase, where emulsion droplets form and break off at the edges of the pores in a drop-by-drop mechanism. A schematic of the membrane emulsification process is shown in Figure 2, with the arrows indicating the flow direction.

[0035] The dispersed phase generally contains a first liquid, which contains a biopolymer dissolved in a solvent, and the continuous phase contains a second liquid that is immiscible with the first liquid. The interaction of the two liquids when the dispersed phase is transported, such as by being pushed through a membrane, is called the dispersion process, and their heterogeneous mixture is called an emulsion, i.e., droplets of the dispersed phase surrounded by the continuous phase.

[0036] The advantages of membrane emulsification compared to conventional emulsification are recognized in the art and include the ability to obtain very fine emulsions with controlled droplet size and narrow droplet size distribution. Furthermore, successful emulsification can be achieved with significantly less energy consumption. And, due to the reduced effect of shear stress, membrane emulsification allows the use of shear-sensitive ingredients such as starches and proteins.

[0037] For biopolymer production, separation has been successfully achieved by phase inversion of dispersed phase droplets in a continuous phase. For cellulose, this is described in ACS Sustainable Chem. Eng. 2017, 5, 7, 5931-5939, incorporated herein by reference. Phase inversion is a chemical phenomenon used to create artificial membranes and is achieved by removing the solvent from a liquid-polymer solution. There are various phase inversion methods, such as immersing the polymer solution in a third liquid, called the antisolvent. The use of antisolvent-based phase inversion has been demonstrated to be particularly effective for the precipitation of biopolymer droplets into particles from dispersed / continuous emulsions.

[0038] Common to both aspects of the present disclosure is the use of a solvent to dissolve the biopolymer to form the dispersed phase, and the use of an anti-solvent to form the biopolymer particles.

[0039] Solvents used in the production of biopolymer particles, especially by membrane emulsification or extrusion, are known, and ionic liquids are generally preferred because they can solubilize recalcitrant biopolymers. Ionic liquids are salts that are in liquid form at temperatures between ambient and 100°C, for example imidazolium-based ionic liquids such as 1-ethyl-3-methylimidazolium acetate (EmimOAc) and 1-butyl-3-methylimidazolium chloride (BmimOAc). In addition, ionic liquids are essentially non-volatile (avoiding fugitive emissions) and are considered to have environmental advantages over other solvents. Ionic liquids can be easily recycled, for example by removing the anti-solvent by distillation.

[0040] However, ionic liquids are not usually used in a pure state. When dissolving biopolymers such as cellulose, a defined amount of co-solvent is often added to the ionic liquid. The use of a co-solvent can aid in dissolving the biopolymer and reduce the amount of expensive ionic liquid required. In the method of forming biopolymer particles, the inclusion of a co-solvent can improve the efficiency and yield of the process by modifying the viscosity of the dispersed phase, thereby reducing the amount of deformed particles.

[0041] Figures 3(a)-3(d) show the shapes of four biopolymer particles obtained by the membrane emulsification process. Figure 3(a) shows an example of particle shapes and sizes that are desirable for certain applications, with individual spherical beads less than 50 μm in diameter. Figure 3(b) shows undesirable shape deformation, with individual teardrop-shaped particles. Figure 3(c) shows undesirable coalescence of multiple spherical particles with diameters greater than 200 μm. Figure 3(d) shows undesirable asymmetric aggregation of multiple beads. Deformation, aggregation, and agglomeration affect both the size and shape distribution of the biopolymer particles, which negatively impacts the yield of biopolymer particles.

[0042] The term "agglomerate" refers to a structure made up of primary particles that can typically be redispersed, and the term "aggregate" refers to a structure made up of primary particles that cannot be redispersed. The term "tailing" refers to particles that are not perfectly spherical and exhibit one or more (usually one) protrusions, such as the teardrop-shaped particles shown in Figure 3(b).

[0043] Since it is difficult to study forming particles in-situ, only theoretical explanations can be given for where and how the deformed shapes, coalesced structures, aggregated structures, etc. form. Without wishing to be bound by any one theory, the inventors believe that the dispersed phase droplets may have undesirable interactions with each other as they flow through the equipment typically used for membrane emulsification or in subsequent process piping, fittings, and equipment. These droplets may coalesce when there is a change in the fluid transport flow regime, such as, for example, a laminar to turbulent transition, a recirculation zone, or a change in flow direction. Another theory is that the dispersed phase droplets may be deformed by shear forces, for example, during the phase inversion process (e.g., as the emulsion flows through the anti-solvent), and these deformed shapes (e.g., teardrops) may be preserved by the anti-solvent. The dispersed phase droplets may also interact during the phase inversion process before or when they come into contact with the anti-solvent, and may coalesce to form larger droplets or group together to form larger structures that are preserved by the anti-solvent. There may also be other mechanisms during the phase inversion process, such as the entrapment of smaller phase inversion particles by larger droplets, followed by the preservation of their structure by the anti-solvent. In an extrusion process as disclosed herein, the sphericity of the resulting particles may depend on parameters such as drop height, temperature and the composition of the dispersed phase, as described in more detail below.

[0044] Typical co-solvents used in combination with ionic liquids are dipolar aprotic solvents such as dimethylsulfoxide (DMSO), dimethylformamide (DMF), etc. However, such solvents are generally not considered environmentally friendly, and their use may therefore negatively impact the overall environmental benefits of the "green" process using ionic liquids. In particular, DMSO is listed in Annex II of Regulation (EC) No. 1223 / 2009 on Cosmetics (available at https: / / echa.europa.eu / cosmetics-prohibited-substances), and DMF is associated with toxic effects. Thus, such co-solvents cannot be used in the manufacturing process of biopolymer particles used in cosmetics and personal care, as well as other applications. The use of dipolar aprotic solvents may also complicate and increase the cost of recycling ionic liquids. For example, some distillation of DMSO is expected during recycling, and the presence of aprotic solvents has been reported to reduce the thermal stability of 1-ethyl-3-methylimidazolium acetate (EmimOAc) [see, e.g., Williams et al., Thermochimica Acta (2018), 669:126-139].

[0045] Next, regarding the poor solvents used in producing biopolymer particles, organic solvents such as ethanol are typical, but again, these substances may reduce the overall environmental benefits of the process, may be associated with safety concerns, and may complicate and increase the cost of recycling the ionic liquid.

[0046] The present disclosure surprisingly avoids the problems discussed above by using an aqueous solvent and an aqueous anti-solvent. Generally, water is considered to be a poor solvent for biopolymers such as cellulose. However, the present inventors have found that including water in the solvent of the dispersed phase can effectively dissolve / disperse biopolymers such as cellulose and provide a dispersed phase composition that can be utilized in the method disclosed herein, allowing biopolymer particles to be produced with good yield.

[0047] The use of aqueous and anti-solvents avoids the use of reagents associated with environmental and safety concerns, particularly those banned for use in cosmetics, personal care products, and other applications. Aqueous and anti-solvents may also simplify and reduce the cost of solvent recycling. In particular, the use of such solvents and anti-solvents may increase the stability of ionic liquids against temperature-induced degradation [Williams et al., Thermochimica Acta(2018), 669:126-139], which may allow, for example, an increased number of recycling cycles to be performed. Finally, the inclusion of water in the dispersed phase may increase the likelihood of beads becoming spherical by reducing tailing, thereby improving the yield of the methods disclosed herein.

[0048] For ease of reference, these and further features of the present invention are described under appropriate section headings. However, the contents under each section are not intended to be limited to the section in which they are described. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0049] Biopolymer Particles All aspects of the present disclosure relate to biopolymer particles. The term "biopolymer" refers to a polymer produced by an organism. In other words, a polymeric biomolecule. There are three main classes of biopolymers classified according to the monomer units used and the structure of the biopolymer formed: polynucleotides (RNA and DNA), which are polymers of 13 or more nucleotide monomers; polypeptides, which are polymers of amino acids; and polysaccharides, which are typically polymeric carbohydrate structures. Other examples of biopolymers include rubber, suberin, melanin, chitin, and lignin.

[0050] In various embodiments of the invention, the biopolymer is selected from the group consisting of polynucleotides, polypeptides and polysaccharides. Preferably, the biopolymer is selected from the group consisting of polypeptides and polysaccharides. More preferably, the biopolymer is a polysaccharide, such as starch, cellulose, chitin, chitosan or glycogen. Even more preferably, the biopolymer is starch or cellulose. Most preferably, the biopolymer is cellulose.

[0051] Cellulose is a linear polymer composed of β-D-glucopyranose units covalently linked by 1→4 glycosidic bonds. Cellulose can be obtained from many different sources, and the present disclosure is not necessarily limited with respect to the origin, form or other characteristics of the cellulose. Cellulose is typically obtained from plant sources, such as virgin pulp or recycled wood pulp. Pulp is a lignocellulosic fibrous material produced by chemical or mechanical separation of cellulose fibers from wood, fiber crops, waste paper or rags. Cellulose can be obtained from virgin sources or, advantageously, from recycled sources.

[0052] In some embodiments, the biopolymer is selected from the group consisting of virgin cellulose, recycled cellulose, pulp cellulose, and microcrystalline cellulose, and combinations thereof. In some embodiments, the biopolymer is virgin cellulose. In some embodiments, the biopolymer is recycled cellulose. In some embodiments, the biopolymer is pulp cellulose. Preferably, the biopolymer is microcrystalline cellulose.

[0053] Microcrystalline cellulose (MCC) is typically made from high-grade refined wood cellulose. Hydrolysis is used to remove the amorphous cellulose until only the microcrystalline form remains. Once the amorphous cellulose portion is removed, it is an inert, white, free-flowing powder. It can be processed in a number of ways, such as reactive extrusion, steam explosion, and acid hydrolysis. One example of a commercially available MCC is Avicel®, manufactured by DuPont.

[0054] The term "particles" is used interchangeably herein with "beads" and refers to solids formed after phase inversion of dispersed phase droplets or after extrusion of the dispersed phase into a poor solvent.

[0055] The size of the biopolymer particles of the present disclosure is not limited. In various embodiments, the particles or beads are microparticles or microbeads. As will be understood by one of skill in the art, microparticles or microbeads are particles / beads having a diameter of 1 to 1000 microns (μm). Such particles can be readily identified by one of skill in the art using, for example, optical microscope images and image analysis software with appropriate detection algorithms (e.g., ImageJ with edge detection algorithms), laser diffraction with commercially available equipment such as the Mastersizer from Malvern Panalytical (e.g., Mastersizer 3000), or sieves of appropriate size. In other embodiments, the particles or beads can have a diameter of more than 1000 μm. Such particles can also be readily identified by one of skill in the art using the equipment discussed above or by using calipers.

[0056] There are various means by which particle size can be controlled and / or varied in the methods of the present disclosure. Non-limiting examples may include varying the flow rate and / or the size of the gap / opening in the extrusion process of the first embodiment, or varying the membrane pore size and / or the flow rate of the continuous phase in the membrane emulsification process of the second embodiment. Such variations are understood by those skilled in the art. In particular, those skilled in the art will understand that such variations can be performed and / or expressed by varying the Weber number (We) of the dispersed phase and / or the Capillary number (Ca) of the continuous phase. The Weber number is defined as follows:

[0057]

number

[0058] In the formula, ρ is the density (unit: kgm -3 ), and v is the velocity of the dispersed phase (units: m -1 ), l is the characteristic length (droplet diameter or membrane hole diameter) (unit: m), σ is the interfacial tension (unit: Nm -1) The capillary number is defined as follows:

[0059]

number

[0060] In the formula, μ is the dynamic viscosity (unit: Nsm -2 ), and V is the characteristic velocity of the continuous phase (unit: m s -1 ) and σ is the interfacial tension between the surfaces (unit: Nm -1 ).

[0061] In some embodiments, the diameter of the biopolymer particles is about 1 μm to about 500 μm. In some embodiments, the diameter of the biopolymer particles may be about 1 μm to about 400 μm. In some embodiments, the diameter of the biopolymer particles is about 1 μm to about 300 μm. In some embodiments, the diameter of the biopolymer particles is about 1 μm to about 200 μm.

[0062] In some embodiments, the biopolymer particles may have a diameter of about 0.2 mm to about 3.0 mm. In some embodiments, the biopolymer particles may have a diameter of about 0.2 mm to about 2.0 mm. In some embodiments, the biopolymer particles may have a diameter of about 0.2 mm to about 1.0 mm.

[0063] In some embodiments, the biopolymer particles may have a diameter of about 1 mm to about 10 mm. In some embodiments, the biopolymer particles may have a diameter of about 1 mm to about 8 mm. In some embodiments, the biopolymer particles may have a diameter of about 1 mm to about 5 mm.

[0064] As further described below, the method of the present disclosure may include removing the biopolymer particles from the solvent / anti-solvent mixture or the anti-solvent / continuous phase mixture. Thus, the particles resulting from the method of the present disclosure may be obtained in a form in which the particles are wetted or immersed in a solvent, such as water. Such particles may be referred to as "wet" beads and may be provided for further use in this form. Alternatively, the particles may be subsequently dried to provide "dry beads". Either form may be used for industrial applications and the disclosure is not limited in this respect. Examples of wet and dry beads are shown in Figures 6-11.

[0065] dispersed phase Both aspects of the present disclosure include a dispersed phase that includes a solvent in which the biopolymer is dispersed or dissolved, the solvent including water. Thus, the term "solvent" refers to any substance (e.g., liquid) that disperses or dissolves the biopolymer. The term "solvent" also includes solvent mixtures.

[0066] The solvent of the dispersed phase includes water and may include an ionic liquid, an organic solvent, an inorganic non-aqueous solvent, or a combination thereof. In various embodiments of the present disclosure, the solvent of the dispersed phase includes water and at least one of an ionic liquid, an organic solvent, an inorganic non-aqueous solvent, or a combination thereof. In various embodiments of the present disclosure, the solvent of the dispersed phase includes water and one or more ionic liquids.

[0067] Non-limiting examples of the solvents other than water for the dispersed phase include methanol, ethanol, ammonia, acetone, acetic acid, n-propanol, n-butanol, isopropyl alcohol, ethyl acetate, dimethyl sulfoxide, sulfuryl chloride, phosphorus chloride, carbon disulfide, morpholine, N-methylmorpholine, NaOH with and without association of urea and thiourea, bromine pentafluoride, hydrogen fluoride, sulfuryl chloride fluoride, acetonitrile, dimethylformamide, hydrocarbon oils and mixtures thereof, toluene, chloroform, carbon tetrachloride, benzene, hexane, pentane, cyclopentane, cyclohexane, 1,4-dioxane, dichloromethane, Examples of suitable solvents include nitromethane, propylene carbonate, formic acid, tetrahydrofuran, diethyl ether, phosphoric acid, 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride, 1-methoxymethyl-3-methylimidazolium bromide, N-ethylpyridinium chloride, N-methylmorpholine-N-oxide, 1-methylimidazole, N,N-dimethylformamide, N,N'-dimethylimidazolidin-2-one, N,N-dimethylacetamide, sulfolane, γ-valerolactone, γ-butyrolactone, N,N,N',N'-tetramethylurea, N-methylpyrrolidinone, and methylene chloride. Those skilled in the art will readily recognize whether exemplary solvents are ionic liquids, organic solvents, and / or inorganic non-aqueous solvents.

[0068] As will be understood by those skilled in the art, the dispersed phase depends on the biopolymer used. In particular, it is within the general knowledge of those skilled in the art to identify suitable solvents for the dispersed phase of the present disclosure. However, in all aspects of the present disclosure, the dispersed phase solvent comprises water. Those skilled in the art may consider water, alone or in mixture with other solvents, to be an effective poor solvent for certain biopolymers, such as cellulose. However, the water contained in the dispersed phase solvent of the present disclosure is considered to be different from the poor solvent used in the aspects of the present disclosure for the purposes of the present disclosure.

[0069] In various embodiments, the solvent of the dispersed phase comprises at least about 0.5% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 1% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 1.5% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 2% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 2.5% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 3% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 3.5% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 4% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 4.5% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 5% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 5.5% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 6% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 6.5% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 7% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 7.5% water by weight. In various embodiments, the solvent of the dispersed phase comprises at least about 8% water by weight.

[0070] In various embodiments of the present disclosure, the solvent of the dispersed phase contains a minimum amount of water as defined in the previous paragraph (e.g., at least about 0.5 wt %), with the maximum water content being determined by the maximum viscosity of the dispersed phase at the temperature at which the dispersed phase is either extruded in the first mode or passed through the membrane in the second mode. The maximum viscosity of the dispersed phase is defined by the viscosity of the control solution at a given temperature and shear rate.

[0071] Viscosity is measured using a rheometer, e.g., a Discovery HR-3 Hybrid Rheometer (TA Instruments) equipped with 40 mm stainless steel parallel plates. The gap is set at 500 μm and the sample is sealed with mineral oil to prevent moisture migration. Logarithmic shear rate sweeps are performed from 0.1 to 100 s with a 10 s immersion at the viscosity measurement temperature before measurement. -1(10 points / decade). Viscosity 1s -1 Record from the Newtonian region at

[0072] In various embodiments, the maximum water content is the water content at which the viscosity of the dispersed phase at the temperature at which it is extruded in the first embodiment or passed through the membrane in the second embodiment is equal to or less than the viscosity of a control solution of x wt. % biopolymer in a 70:30 mixture of DMSO:non-aqueous solvent at room temperature using the measurement method described above, where x is equal to or greater than the concentration of biopolymer in the dispersed phase of the invention, the biopolymer being the same in both the control solution and the dispersed phase of the invention. The non-aqueous solvent is the solvent of the dispersed phase other than water (including any optional components described below).

[0073] For example, a low biopolymer concentration in water and ionic liquid solvents is expected to have a lower viscosity at a given temperature and shear rate than a high biopolymer concentration, thereby tolerating a higher water content in the dispersed phase solvent. Thus, the water concentration is disclosed above only by a lower limit or minimum content. A person skilled in the art can easily determine the maximum water content from the disclosure herein, and it is believed that limiting the maximum water content to an absolute value would unduly limit the scope of the present disclosure.

[0074] The degree of polymerization of the biopolymer is also expected to affect the viscosity of the dispersed phase. The degree of polymerization is the number of monomer units in the biopolymer and can be calculated as the ratio of the number average molecular weight of the biopolymer to the molecular weight of the repeating unit. The higher the degree of polymerization, the more entanglement of the chains in the solution and the higher the viscosity. The degree of polymerization of microcrystalline cellulose is typically about 200 to about 400. The degree of polymerization of Avicel® is specified to be less than 350.

[0075] In various embodiments of the present disclosure, the biopolymer has a degree of polymerization less than about 400. In various embodiments of the present disclosure, the biopolymer has a degree of polymerization less than about 350. In various embodiments of the present disclosure, the biopolymer has a degree of polymerization from about 50 to about 400. In various embodiments of the present disclosure, the biopolymer has a degree of polymerization from about 100 to about 400. In various embodiments of the present disclosure, the biopolymer has a degree of polymerization from about 150 to about 400. In various embodiments of the present disclosure, the biopolymer has a degree of polymerization from about 200 to about 400, e.g., from about 200 to about 350.

[0076] A control solution of 8 wt% microcrystalline cellulose in a 70:30 mixture of DMSO:EmimOAc is disclosed in James Coombs OBrien et al., Continuous Production of Cellulose Microbeads via Membrane Emulsification. ACS Sustainable Chemistry & Engineering 2017 5 (7), 5931-5939, incorporated herein by reference. This is the control solution used in the examples below. It has a viscosity of 100 MPa at room temperature and a shear rate of 1 s when measured as described above. -1 The viscosity is 1.89 Pa s at 30° C. and this viscosity is used to determine the maximum water content of the dispersed phase containing 4, 6 or 8 wt % MCC in EmimOAc used at temperatures between 30° C. and 60° C. in the extrusion process. The drop height can also be varied to control the sphericity of the beads, as described in more detail below.

[0077] Although an upper limit on the water content would unduly limit the scope of this disclosure, in various embodiments, the solvent of the dispersed phase comprises from about 0.5% to about 12% water by weight. In various embodiments, the solvent comprises from about 1% to about 12% water by weight. In various embodiments, the solvent comprises from about 1.5% to about 12% water by weight. In various embodiments, the solvent comprises from about 2% to about 12% water by weight. In various embodiments, the solvent comprises from about 2.5% to about 12% water by weight. In various embodiments, the solvent comprises from about 3% to about 12% water by weight. In various embodiments, the solvent comprises from about 3.5% to about 12% water by weight. In various embodiments, the solvent comprises from about 4% to about 12% water by weight. In various embodiments, the solvent comprises from about 4.5% to about 12% water by weight. In various embodiments, the solvent comprises from about 5% to about 12% water by weight. In various embodiments, the solvent comprises about 5.5% to about 12% water by weight.In various embodiments, the solvent comprises about 6% to about 12% water by weight.

[0078] In various embodiments, the solvent comprises about 0.5% to about 10% water by weight. In various embodiments, the solvent comprises about 1% to about 10% water by weight. In various embodiments, the solvent comprises about 1.5% to about 10% water by weight. In various embodiments, the solvent comprises about 2% to about 10% water by weight. In various embodiments, the solvent comprises about 2.5% to about 10% water by weight. In various embodiments, the solvent comprises about 3% to about 10% water by weight. In various embodiments, the solvent comprises about 3.5% to about 10% water by weight. In various embodiments, the solvent comprises about 4% to about 10% water by weight. In various embodiments, the solvent comprises about 4.5% to about 10% water by weight. In various embodiments, the solvent comprises about 5% to about 10% water by weight. In various embodiments, the solvent comprises about 5.5% to about 10% water by weight. In various embodiments, the solvent comprises about 6% to about 10% water by weight.

[0079] In various embodiments, the dispersed phase solvent comprises water and an ionic liquid. The ionic liquid may be selected from 1-ethyl-3-methylimidazolium acetate (EmimOAc), 1-butyl-3-methylimidazolium chloride (BmimOAc), and combinations thereof. In some embodiments, the dispersed phase solvent comprises water and one or more organic solvents. In other embodiments, the dispersed phase solvent is substantially free of organic solvents. The term "substantially free" is defined above. Those skilled in the art will appreciate that when the dispersed phase solvent consists of water and an ionic liquid, the total weight percent of the water and ionic liquid in the dispersed phase solvent is 100% by weight. If water is present, for example, in an amount of at least 0.5% by weight, the ionic liquid may be present in an amount of at least 99.5% by weight, provided that the sum of the water and the ionic liquid is 100% by weight. In other words, the ionic liquid may be present as the balance of the solvent.

[0080] Preferably, the solvent used for the dispersed phase is environmentally friendly. The term "environmentally friendly" means that the solvent is not harmful to the environment, i.e., non-toxic, so that it can be disposed of without the need for specialized equipment or processes. It is known in the art that polysaccharides are poorly soluble in most common solvents. It is also known in the art that solvents that dissolve polysaccharides are often toxic and / or highly selective. Thus, when the biopolymer is a polysaccharide, such as cellulose, starch, chitin, glycogen and / or chitosan, the dispersed phase solvent can include an ionic liquid in addition to water. The dissolution of cellulose with the ionic liquid 1-butyl-3-methylimidazolium chloride is described, for example, in "Richard et al., J. Am. Chem. Soc. 2002, 124, 4974-4975". Verma et al, Sustainable Chemistry and Pharmacy 13(2019), 100162, similarly describes ionic liquids and co-solvents and the solubility of cellulose in ionic liquids, each of which is incorporated herein by reference.

[0081] The concentration of the biopolymer in the dispersed phase is not limited and can be any concentration suitable for the methods of the present disclosure. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.1% to about 15% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.5% to about 15% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 1% to about 15% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 1.5% to about 15% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 15% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 2.5% to about 15% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 15% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 3.5% to about 15% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 15% by weight.

[0082] In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.1% to about 12% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.5% to about 12% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 1% to about 12% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 1.5% to about 12% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 2.5% to about 12% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 12% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 3.5% to about 12% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 12% by weight.

[0083] In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.1% to about 10% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.5% to about 10% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 1% to about 10% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 1.5% to about 10% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 10% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 2.5% to about 10% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 10% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 3.5% to about 10% by weight. In various embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight.

[0084] The dispersed phase may further comprise optional ingredients, including but not limited to surfactants, porogens, active ingredients, air pockets, multiple emulsions, pigments and dyes. The level of the optional ingredients is not critical to the present disclosure. In various embodiments, the dispersed phase comprises a co-solvent.

[0085] The surfactant can be any suitable surfactant known in the art, for example, ionic or non-ionic surfactant. Ionic surfactants include sulfates, sulfonates, phosphates and carboxylates, such as alkyl sulfates, ammonium lauryl sulfate, sodium lauryl sulfate, alkyl ether sulfates, sodium laureth sulfate and sodium myreth sulfate, sodium dioctyl sulfosuccinate, perfluorooctane sulfonate, perfluorobutane sulfonate, alkylbenzene sulfonate, alkylaryl ether phosphates, alkyl ether phosphates and alkyl carboxylates. Non-ionic surfactants can include polyethers, polyoxyalkylene derivatives of hexitols, partial long-chain fatty acid esters such as sorbitan oleate, ethylene oxide derivatives of long-chain alcohols, ethoxylated vegetable oils, polydimethylsiloxanes and ethylene oxide / propylene oxide copolymers.

[0086] The temperature of the dispersed phase is not limited, but in various embodiments, the temperature can be controlled to ensure that the viscosity of the dispersed phase is equal to or less than the maximum value described above. For example, the temperature can be controlled to ensure that a dispersed phase having a particular concentration of biopolymer and a particular concentration of water has a viscosity equal to or less than the maximum viscosity described above (i.e., at a particular temperature and shear rate (e.g., ambient temperature and 1 s -1 The relationship between these characteristics is discussed herein, including in the Examples below.

[0087] Phrases such as "temperature of the dispersed phase" or "the dispersed phase is at a temperature of" refer to the temperature of the dispersed phase prior to extrusion or membrane emulsification (e.g. when the dispersed phase is placed in an apparatus for such extrusion or emulsification) and / or the temperature of the apparatus during extrusion or emulsification of the dispersed phase. As explained in more detail below, the extrusion or emulsification means may be heated so that the dispersed phase remains at an elevated temperature in situ. Preferably, the extrusion means is directly heated by one or more heating means, as explained further below.

[0088] In some embodiments, the dispersed phase is at ambient or room temperature, i.e., about 20° C. to about 25° C. In various embodiments, the dispersed phase is heated above ambient temperature. The dispersed phase can be heated using any suitable means. The dispersed phase is preferably heated in situ, such as by heating the vessel containing the dispersed phase and / or the extrusion or emulsification means, such that there is no temperature loss, prior to extrusion or membrane emulsification. In the extrusion process, for example, a heated syringe and / or needle can be used. Suitable heating devices include a heating element, such as a Peltier element, and a means for regulating the temperature, such as a thermocouple and a controller.

[0089] Thus, in various embodiments, the temperature of the dispersed phase is from about 5° C. to less than about 100° C., from about 10° C. to less than about 100° C., from about 15° C. to less than about 100° C., from about 20° C. to less than about 100° C., from about 25° C. to less than about 100° C., or from about 30° C. to less than about 100° C. The maximum temperature is set by the point at which evaporation of water from the dispersed phase is no longer possible and / or decomposition of the ionic liquid begins to occur, which can be readily determined by one of ordinary skill in the art.

[0090] In various embodiments, the temperature of the dispersed phase is about 5° C. to about 90° C., about 10° C. to about 90° C., about 15° C. to about 90° C., about 20° C. to about 90° C., about 25° C. to about 90° C., or about 30° C. to about 90° C. In various embodiments, the temperature of the dispersed phase is about 5° C. to about 80° C., about 10° C. to about 80° C., about 15° C. to about 80° C., about 20° C. to about 80° C., about 25° C. to about 80° C., about 30° C. to about 80° C., or about 40° C. to about 80° C.

[0091] The objective of the present disclosure is to produce biopolymer particles with good sphericity. In this regard, the inventors have found that the temperature of the dispersed phase and the amount of biopolymer in the dispersed phase may provide advantages. Thus, the above disclosure of the biopolymer concentration can be combined with the disclosure of the water content and, optionally, the disclosure of the dispersed phase temperature.

[0092] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.5% to about 12% by weight, and the solvent comprises at least about 0.5% by weight of water. As described above, the maximum water content should be determined based on the maximum viscosity of the dispersed phase. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 1% to about 12% by weight, and the solvent comprises at least about 0.5% by weight of water. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 1.5% to about 12% by weight, and the solvent comprises at least about 0.5% by weight of water. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, and the solvent comprises at least about 0.5% by weight of water. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2.5% to about 12% by weight, and the solvent comprises at least about 0.5% by weight of water. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 12% by weight, and the solvent comprises at least about 0.5% by weight of water. Each of these biopolymer concentration ranges can be combined with the water content ranges above, for example, from about 0.5% to about 12% by weight.

[0093] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 10% by weight, and the solvent comprises at least about 1% by weight of water. As above, the maximum water content should be determined based on the maximum viscosity of the dispersed phase. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 10% by weight, and the solvent comprises at least about 1% by weight of water. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, and the solvent comprises at least about 1% by weight of water. Each of these biopolymer concentration ranges can be combined with the water content ranges described above, for example, about 1% to about 12% by weight.

[0094] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.5% to about 12% by weight, the solvent comprises at least 0.5% water by weight, and the temperature of the dispersed phase is about 5°C to about 80°C (including ambient temperature to 80°C). As mentioned above, the maximum water content should be determined based on the maximum viscosity of the dispersed phase. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 1% to about 12% by weight, the solvent comprises at least 0.5% water by weight, and the temperature of the dispersed phase is about 5°C to about 80°C (including ambient temperature to 80°C). In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 1.5% to about 12% by weight, the solvent comprises at least 0.5% water by weight, and the temperature of the dispersed phase is about 5°C to about 80°C (including ambient temperature to 80°C). In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, the solvent comprises at least 0.5% by weight of water, and the temperature of the dispersed phase is about 5°C to about 80°C (including ambient temperature to 80°C). In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2.5% to about 12% by weight, the solvent comprises at least 0.5% by weight of water, and the temperature of the dispersed phase is about 5°C to about 80°C (including ambient temperature to 80°C). In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 12% by weight, the solvent comprises at least 0.5% by weight of water, and the temperature of the dispersed phase is about 5°C to about 80°C (including ambient temperature to 80°C). Each of these biopolymer concentration and dispersed phase temperature ranges can be combined with the water content ranges described above, such as about 0.5% to about 12% by weight. Similarly, each of these biopolymer concentration and water content ranges can be combined with the dispersed phase temperature ranges described above, such as about 30°C to about 70°C.

[0095] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 10% by weight, the solvent comprises at least about 1% water by weight, and the temperature of the dispersed phase is about 5° C. to about 80° C. (including ambient temperature to 80° C.). As noted above, the maximum water content should be determined based on the maximum viscosity of the dispersed phase. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 10% by weight, the solvent comprises at least about 1% water by weight, and the temperature of the dispersed phase is about 5° C. to about 80° C. (including ambient temperature to 80° C.). In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, the solvent comprises at least about 1% water by weight, and the temperature of the dispersed phase is about 5° C. to about 80° C. (including ambient temperature to 80° C.). Each of these biopolymer concentration ranges can be combined with the water content ranges described above, for example, about 1% to about 12% by weight. Similarly, each of these biopolymer concentration ranges and water content ranges can be combined with the dispersed phase temperature ranges listed above, such as from about 30°C to about 70°C.

[0096] In some embodiments, the biopolymer is present in the dispersed phase in an amount of 2% to about 12% by weight, the solvent comprises about 2% to about 12% by weight water, and the temperature of the dispersed phase is about 5° C. to about 80° C. (including ambient temperature to 80° C.). In some embodiments, the biopolymer is present in the dispersed phase in an amount of 2% to about 12% by weight, the solvent comprises about 4% to about 10% by weight water, and the temperature of the dispersed phase is about 5° C. to about 80° C. (including ambient temperature to 80° C.).

[0097] In some embodiments, the biopolymer is present in the dispersed phase in an amount of 4% to about 10% by weight, the solvent comprises about 2% to about 12% by weight water, and the temperature of the dispersed phase is about 5° C. to about 80° C. (including ambient temperature to 80° C.). In some embodiments, the biopolymer is present in the dispersed phase in an amount of 4% to about 10% by weight, the solvent comprises about 4% to about 10% by weight water, and the temperature of the dispersed phase is about 5° C. to about 80° C. (including ambient temperature to 80° C.). Antisolvent

[0098] In all aspects of the present disclosure, the anti-solvent comprises water, i.e., it is aqueous. In various embodiments, the anti-solvent can comprise water and an organic solvent, such as an alcohol or acetone, or other organic solvent known in the art. Suitable alcohols include ethanol and / or methanol. Preferably, the anti-solvent of the present disclosure is environmentally friendly. More preferably, both the solvent and the anti-solvent of the present disclosure are environmentally friendly. Thus, in various embodiments, the anti-solvent is substantially free of organic solvents. In various embodiments, the anti-solvent is water or consists of water.

[0099] In various embodiments, the anti-solvent further comprises an ionic liquid. In some embodiments, the anti-solvent may comprise water and an ionic liquid prior to phase inversion or extrusion of the dispersed phase. In other embodiments, the ionic liquid can be introduced into the anti-solvent during phase inversion or extrusion. In some embodiments where the dispersed phase comprises an ionic liquid, the ionic liquid can be introduced from the dispersed phase into the anti-solvent during the phase inversion or extrusion process.

[0100] In various embodiments, the concentration of the ionic liquid in the anti-solvent is up to about 50% by weight, where the term "up to" is understood to mean greater than zero. In various embodiments, the concentration of the ionic liquid in the anti-solvent is up to about 40% by weight. In various embodiments, the concentration of the ionic liquid in the anti-solvent is up to about 30% by weight. In various embodiments, the concentration of the ionic liquid in the anti-solvent is up to about 20% by weight. In various embodiments, the concentration of the ionic liquid in the anti-solvent is up to about 10% by weight.

[0101] When the anti-solvent comprises water and an ionic liquid, the ionic liquid can be 1-ethyl-3-methylimidazolium acetate (EmimOAc), 1-butyl-3-methylimidazolium chloride (BmimOAc), or a mixture thereof. In various embodiments, the ionic liquid is 1-ethyl-3-methylimidazolium acetate (EmimOAc).

[0102] The temperature of the anti-solvent is not particularly limited in the extrusion process of the present disclosure. In various embodiments, the temperature of the anti-solvent is about 5°C to about 80°C. In various embodiments, the temperature of the anti-solvent is about 10°C to about 70°C. In various embodiments, the temperature of the anti-solvent is about 15°C to about 60°C.

[0103] In various embodiments of the membrane emulsification process of the present disclosure, the temperature of the anti-solvent is at ambient temperature such that the phase inversion occurs at ambient temperature, i.e., about 20 to about 25° C. In such embodiments, the anti-solvent has a temperature of about 20° C. to about 25° C. Alternatively, and preferably, the anti-solvent is cooled to a temperature below ambient temperature, i.e., below about 20° C. For example, in some embodiments of the second aspect, the anti-solvent can be cooled to a temperature T2 for phase inversion (b), where T2 is equal to or lower than T disp Preferably, T2 is substantially equal to T1, more preferably, T2 is equal to T1, T1 being defined above.

[0104] The advantage of controlling the temperature of the anti-solvent (T2) in such an embodiment is to prevent premature thawing of the frozen droplets. Without wishing to be bound by any theory, the inventors believe that by cooling the anti-solvent to T2, the droplets remain frozen (and thus spherical and non-aggregated) while the continuous phase around them is removed by phase inversion. The anti-solvent can contact the droplets' surface, thereby causing precipitation of the biopolymer and hardening of the precipitate surface. Furthermore, when the frozen dispersed phase droplets thaw, the anti-solvent converts the dissolved biopolymer droplets into their beads / particles while leaching the solvent system into the anti-solvent.

[0105] Extrusion In the first aspect of the present disclosure, the dispersed phase is extruded into an anti-solvent to form particles of biopolymers. In various embodiments, the dispersed phase is extruded through a fluid medium by capillary extrusion. The fluid medium may be, for example, air. Examples of capillaries that can extrude the dispersed phase include glass capillaries, microfluidic channels, and (hypodermic) injection needles. The material for manufacturing such capillaries is not limited, and a person skilled in the art will be able to select a suitable capillary that is compatible with the dispersed phase.

[0106] The surface of the capillary can also be modified. The capillary can be, for example, treated, coated or lined to change its wetting properties. Such modification of the capillary material can, for example, change the hydrophilicity / hydrophobicity of the capillary material, thereby changing the wettability of the capillary surface. For example, the capillary can be treated with a reactive hydrophobic compound such as a silane to form a hydrophobic surface layer, or a hydrophobic compound can be deposited on the capillary surface by a method such as chemical vapor deposition. In another example, the metal needle can be lined with PTFE (polytetrafluoroethylene). The identification of suitable surface modifications is specifically within the general knowledge of the person skilled in the art. Such surface modifications can change the size of the biopolymer particles obtained by the methods disclosed herein and / or improve the regularity of the size and shape of said particles.

[0107] The size of the gap or opening, e.g., the diameter of a capillary or the gauge of a needle, is not limited. However, it will be readily apparent to one skilled in the art that the size of the gap or opening will affect the size of the dispersed phase droplets extruded therethrough. In general, larger gaps or openings are expected to produce larger dispersed phase droplets, and conversely, smaller gaps or openings are expected to produce smaller dispersed phase droplets. One skilled in the art will be able to select the appropriate size of the gap / opening.

[0108] The diameter of the gap or opening through which the dispersed phase is extruded can be less than about 3 mm, less than about 2.5 mm, less than about 2 mm, less than about 1.5 mm, less than about 1 mm, less than about 0.75 mm, less than about 0.5 mm, less than about 0.4 mm, less than about 0.3 mm, or less than about 0.2 mm. In various embodiments, the diameter of the gap or opening through which the dispersed phase is extruded can be greater than about 0.1 mm. In various embodiments, the diameter of the gap or opening through which the dispersed phase is extruded can be greater than about 0.1 mm and less than about 3 mm, greater than about 0.1 mm and less than about 2.5 mm, greater than about 0.1 mm and less than about 2 mm, greater than about 0.1 mm and less than about 1.5 mm, greater than about 0.1 mm and less than about 1 mm, greater than about 0.1 mm and less than about 0.75 mm, greater than about 0.1 mm and less than about 0.5 mm, greater than about 0.1 mm and less than about 0.4 mm, or greater than about 0.1 mm and less than about 0.3 mm. In other embodiments, the diameter of the gap or opening through which the dispersed phase is extruded can be from about 0.1 mm to about 1 mm, from about 1 mm to about 2 mm, or from about 2 mm to about 3 mm.

[0109] In various embodiments, the dispersed phase is extruded through a needle. The needle may be blunt, although the disclosure is not limited in this respect. In various embodiments, the needle gauge size is 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, or 10 gauge.

[0110] The extrusion rate is not limited and can be controlled using standard laboratory equipment, such as a syringe pump. In various embodiments, the extrusion rate is less than about 1 mL / min, less than about 100 μL / min, less than about 10 μL / min, less than about 1 μL / min, or less than about 100 nL / min. In other embodiments, the extrusion rate is from about 1 μL / min to about 1 mL / min, or from about 10 μL / min to about 100 μL / min.

[0111] In some embodiments of the first aspect, the dispersed phase is first extruded through a fluid medium into a mold, and then the extruded dispersed phase is contacted with an anti-solvent. In various embodiments, the mold can impart a shape to the biopolymer particles formed upon contact of the extruded dispersed phase with the anti-solvent. The shape of the biopolymer particles is not limited, and in this case is determined by the shape of the mold. The mold can be made of any suitable material that is compatible with the dispersed phase and the anti-solvent, for example, a silicone polymer such as polydimethylsiloxane (PDMS). The mold can be manufactured by molding the mold material or by 3D printing the mold material. The mold containing the extruded dispersed phase can be immersed in the anti-solvent to contact the extruded dispersed phase with the anti-solvent. The mold can be removed after forming the biopolymer particles, or can be retained during further processing steps such as washing and filtering / extracting the biopolymer particles.

[0112] If no mold is used, extrusion can occur in the anti-solvent; i.e., the dispersed phase can be exposed to the anti-solvent immediately after extrusion (e.g., when the gap or opening is immersed in the anti-solvent). Alternatively, and preferably, in various embodiments, the extruded dispersed phase is dripped from a height above the surface of the anti-solvent. This can be seen in Figure 1, where the extruded dispersed phase is dripped from a height d above the surface of the anti-solvent.

[0113] The drop height can affect the sphericity of the particles obtained by the extrusion process. Without being bound by any theory, it is believed that a higher drop height can reduce tailing (i.e., improve sphericity) by allowing more time for the falling droplets to be subjected to cohesive forces. Thus, in various embodiments, the extruded phase is dropped from a height of at least 10 cm above the surface of the anti-solvent. In various embodiments, the extruded phase is dropped from a height of at least 20 cm above the surface of the anti-solvent. In various embodiments, the extruded phase is dropped from a height of at least 30 cm above the surface of the anti-solvent. In various embodiments, the extruded phase is dropped from a height of at least 40 cm above the surface of the anti-solvent. In various embodiments, the extruded phase is dropped from a height of at least 50 cm above the surface of the anti-solvent. In various embodiments, the extruded phase is dropped from a height of at least 60 cm above the surface of the anti-solvent. In various embodiments, the extruded phase is dropped from a height of at least 70 cm above the surface of the anti-solvent or at least 80 cm above the surface of the anti-solvent.

[0114] The maximum drop height is determined by the distance at which non-spherical particles are formed. This is known in the art and is easily understood by the skilled artisan. For example, it can be determined visually. However, in various embodiments, the extruded phase is dropped from a height of less than 80 cm above the surface of the anti-solvent. In various embodiments, the extruded phase is dropped from a height of less than 70 cm above the surface of the anti-solvent. In various embodiments, the extruded phase is dropped from a height of less than 60 cm above the surface of the anti-solvent. In various embodiments, the extruded phase is dropped from a height of less than 50 cm above the surface of the anti-solvent.

[0115] In various embodiments, the extruded phase is dropped from a height of about 1 cm to about 80 cm, preferably from a height of about 5 cm to about 70 cm, and more preferably from a height of about 10 cm to about 60 cm above the surface of the poor solvent.

[0116] In various embodiments, the extruded phase is dripped from a height of about 10 cm to about 80 cm above the surface of the poor solvent. In various embodiments, the extruded phase is dripped from a height of about 10 cm to about 70 cm above the surface of the poor solvent. In various embodiments, the extruded phase is dripped from a height of about 10 cm to about 60 cm above the surface of the poor solvent. In various embodiments, the extruded phase is dripped from a height of about 10 cm to about 50 cm above the surface of the poor solvent.

[0117] In various embodiments, the extruded phase is dripped from a height of about 20 cm to about 80 cm above the surface of the poor solvent. In various embodiments, the extruded phase is dripped from a height of about 20 cm to about 70 cm above the surface of the poor solvent. In various embodiments, the extruded phase is dripped from a height of about 20 cm to about 60 cm above the surface of the poor solvent. In various embodiments, the extruded phase is dripped from a height of about 20 cm to about 50 cm above the surface of the poor solvent. In various embodiments, the extruded phase is dripped from a height of about 20 cm to about 40 cm above the surface of the poor solvent.

[0118] As already discussed above, the sphericity of the biopolymer particles can also be affected by the temperature of the dispersed phase and the amount of biopolymer in the dispersed phase. Thus, in the method of the first aspect, the sphericity of the biopolymer particles can be affected by one or more of the drop height, the temperature of the dispersed phase; and the amount of biopolymer in the dispersed phase at a given water content in the solvent in the dispersed phase.

[0119] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.5% to about 12% by weight, the solvent comprises at least about 0.5% water by weight, and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. As described above, the maximum water content should be determined based on the maximum viscosity of the dispersed phase. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 1% to about 12% by weight, the solvent comprises at least about 0.5% water by weight, and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 1.5% to about 12% by weight, the solvent comprises at least about 0.5% water by weight, and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, the solvent comprises at least about 0.5% water by weight, and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2.5% to about 12% by weight, the solvent contains at least about 0.5% water by weight, and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 12% by weight, the solvent contains at least about 0.5% water by weight, and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. Each of these biopolymer concentration ranges can be combined with the water content ranges above, e.g., about 0.5% to about 12% by weight, and / or the drop height ranges above, e.g., about 10 cm to about 60 cm or about 20 cm to about 50 cm.

[0120] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 10% by weight, the solvent contains at least about 1% water by weight, and the extruded dispersed phase is dropped from a height of about 10 cm to about 70 cm. As mentioned above, the maximum water content should be determined based on the maximum viscosity of the dispersed phase. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 10% by weight, the solvent contains at least about 1% water by weight, and the extruded dispersed phase is dropped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, the solvent contains at least about 1% water by weight, and the extruded dispersed phase is dropped from a height of about 10 cm to about 70 cm. Each of these biopolymer concentration ranges can be combined with the water content ranges described above, such as about 1% to about 12% by weight, and / or the drop height ranges described above, such as about 10 cm to about 60 cm or about 20 cm to about 50 cm.

[0121] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 0.5% to about 12% by weight, the solvent contains at least about 0.5% water by weight, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. As described above, the maximum water content should be determined based on the maximum viscosity of the dispersed phase. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 1% to about 12% by weight, the solvent contains at least about 0.5% water by weight, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 1.5% to about 12% by weight, the solvent contains at least about 0.5% water by weight, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, the solvent contains at least about 0.5% water by weight, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2.5% to about 12% by weight, the solvent contains at least about 0.5% water by weight, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 12% by weight, the solvent contains at least about 0.5% water by weight, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. Each of these biopolymer concentrations and dispersed phase temperature ranges can be combined with the water content ranges described above, such as about 0.5% to about 12% by weight, and / or the drop height ranges described above, such as about 10 cm to about 60 cm or about 20 cm to about 50 cm. Similarly, each of these biopolymer concentrations and water content ranges can be combined with the dispersed phase temperature ranges described above, such as about 30° C. to about 70° C., and / or the drop height ranges described above, such as about 10 cm to about 60 cm or about 20 cm to about 50 cm.

[0122] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 20° C. to about 80° C., and the extruded dispersed phase is dropped from a height of about 10 cm to about 70 cm above the surface of the poor solvent. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 20° C. to about 80° C., and the extruded dispersed phase is dropped from a height of about 10 cm to about 60 cm above the surface of the poor solvent.

[0123] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 10% by weight, the solvent contains at least about 1% water by weight, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. As noted above, the maximum water content should be determined based on the maximum viscosity of the dispersed phase.

[0124] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 3% to about 10% by weight, the solvent contains at least about 1% water by weight, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, the solvent contains at least about 1% water by weight, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm. Each of these biopolymer concentration ranges can be combined with the water content ranges described above, such as about 1% to about 12% by weight, and / or the drop height ranges described above, such as about 10 cm to about 60 cm or about 20 cm to about 50 cm. Similarly, each of these biopolymer concentration and water content ranges can be combined with the above-mentioned dispersed phase temperature ranges, such as from about 30° C. to about 70° C., and / or the above-mentioned drop height ranges, such as from about 10 cm to about 60 cm or from about 20 cm to about 50 cm.

[0125] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 20° C. to about 100° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm above the surface of the poor solvent. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 20° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 60 cm above the surface of the poor solvent.

[0126] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm above the surface of the poor solvent. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 2% to about 12% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 20 cm to about 60 cm above the surface of the poor solvent.

[0127] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 20° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm above the surface of the poor solvent. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 20° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 60 cm above the surface of the poor solvent.

[0128] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 10 cm to about 70 cm above the surface of the poor solvent. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 30° C. to about 80° C., and the extruded dispersed phase is dripped from a height of about 20 cm to about 60 cm above the surface of the poor solvent.

[0129] In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 30° C. to about 70° C., and the extruded dispersed phase is dripped from a height of about 20 cm to about 70 cm above the surface of the poor solvent. In some embodiments, the biopolymer is present in the dispersed phase in an amount of about 4% to about 10% by weight, the solvent contains about 2% to about 12% by weight of water, the temperature of the dispersed phase is about 30° C. to about 70° C., and the extruded dispersed phase is dripped from a height of about 30 cm to about 60 cm above the surface of the poor solvent.

[0130] The method of the first aspect may further include a step of separating the biopolymer particles from the poor solvent. The means of separating the biopolymer particles from the poor solvent are not limited and are known to those skilled in the art. For example, in various embodiments, the biopolymer particles can be separated from the poor solvent by a filtration process. The filtration process is not limited and can include mechanical filtration or other types of filtration (e.g., using equipment known in the art such as a liquid centrifuge). In various embodiments, a filtration medium (e.g., a filter) can be used to filter the biopolymer particles from the poor solvent, thereby collecting the biopolymer particles.

[0131] In various embodiments, the biopolymer particles can be allowed to settle in a vessel and the anti-solvent removed or decanted to leave the biopolymer particles wet with the remaining anti-solvent, or the biopolymer particles can be separated by a centrifuge or disc stack separator.

[0132] In various embodiments, the biopolymer particles can be washed one or more times with an aqueous solvent, including, for example, water. Such a washing step can be performed to remove any residual ionic liquid that may be present. In various embodiments, the solvent in which the biopolymer particles are immersed can be exchanged with an alternative solvent. In various embodiments, the biopolymer particles are dried. The drying process is not limited and can include, for example, drying the beads in a desiccator and / or under reduced pressure.

[0133] Membrane Emulsification The membrane emulsification process of the second embodiment includes passing the dispersed phase through the continuous phase through a membrane to form an emulsion. The membrane is not limited and can be any porous structure suitable for the membrane emulsification process. For example, the membrane can be a plate with holes that function as pores (e.g., micron-sized holes), a perforated metal tube, or sintered porous glass.

[0134] The term "emulsion" refers to a class of two-phase systems of matter in which both phases are liquids. Emulsions are a type of colloid and generally consist of two immiscible liquids. In various embodiments of the invention, the emulsion may be a macroemulsion. This is an emulsion in which the particles of the dispersed phase have diameters of about 1-1000 microns. The term "sol" refers to a general class of two-phase systems of matter in which the continuous phase is a liquid and the dispersed phase is a solid.

[0135] The membrane emulsification is also not limited and may be any membrane emulsification process known in the art. For example, the membrane emulsification process may be cross-flow membrane emulsification, rotating membrane emulsification, vibrating membrane emulsification, or a combination thereof. As understood in the art, the terms "cross-flow", "rotating" and "vibrating" refer to methods used to generate shear on the membrane surface. It is contemplated that the continuous phase may move relative to a stationary membrane, for example, to generate shear, or the membrane may move relative to the stationary phase. Alternatively, the dispersed phase may be injected into a stationary continuous phase. Known process parameters such as membrane type, average pore size and porosity, cross-flow velocity, transmembrane pressure, and emulsifiers may also be used. In various embodiments of the present invention, the membrane emulsification may include cross-flow systems, stirred cell tube membranes, stirred cell flat membranes, rotating flat membranes, vibrating / rotating tube membranes, and / or premixed membrane emulsification.

[0136] International Patent Application No. WO01 / 45830 describes an example of rotating membrane emulsification. International Patent Application No. WO2012 / 094595 describes an example of cross-flow membrane emulsification. Pedro S. Silva et al. “Azimuthally Oscillating Membrane Emulsification for Controlled Droplet Production”, AIChE Journal 2015 Vol. 00, No. 00 describes oscillating membrane emulsification: specifically, a membrane emulsification system including a tubular metal membrane that periodically oscillates azimuthally in a gently cross-flowing continuous phase. WO2019 / 092461 describes cross-flow membrane emulsification. Each of these method descriptions is incorporated herein by reference.

[0137] In various embodiments of the present disclosure, the membrane emulsification is cross-flow membrane emulsification, preferably an emulsification process in which the continuous phase moves relative to a stationary membrane.

[0138] As will be appreciated by those skilled in the art, the dispersed and continuous phases depend on the biopolymer used. Various characteristics of the solvent for the dispersed phase have already been discussed above, and said characteristics can be combined with the embodiments disclosed herein, either individually or in any combination thereof. The continuous phase comprises a solvent that is immiscible with the dispersed phase, such that an emulsion is formed when the dispersed phase is forced through the porous membrane. The term "solvent" has the meaning as already defined above.

[0139] The two phases, the dispersed phase and the continuous phase, must be immiscible with each other. It therefore follows that the solvents of each phase must be immiscible with each other. It is specifically within the general knowledge of the person skilled in the art to identify suitable solvents for the dispersed and continuous phases of the second embodiment.

[0140] The solvent of the continuous phase is not limited except that it must be immiscible with the dispersed phase. The solvent of the continuous phase may be a non-polar solvent. In various embodiments, the solvent of the continuous phase may be selected from hydrocarbon-based oils and blends thereof. Such hydrocarbon-based oils may be mineral oils, vegetable oils, or synthetic oils. The solvent of the continuous phase may further include water and / or one or more ionic liquids that may be present in residual amounts. Such water and / or ionic liquid residues may result from the solvent recycling process.

[0141] Preferably, the solvent used for the continuous phase is environmentally friendly. More preferably, the solvent used for both the dispersed and continuous phases is environmentally friendly. The term "environmentally friendly" has the meaning already defined above.

[0142] The continuous phase may further comprise optional ingredients, including but not limited to co-solvents, surfactants, pigments and dyes. The level of the optional ingredients is not critical to the present disclosure. In various embodiments, the continuous phase comprises a co-solvent.

[0143] The co-solvent is not limited and may be any solvent known in the art. In various embodiments, the co-solvent may be selected from hydrocarbon-based oils and mixtures thereof. Such hydrocarbon-based oils may be mineral oils, vegetable oils, or synthetic oils. The co-solvent may further be a co-solvent mixture.

[0144] The surfactant is as defined above.

[0145] In various embodiments of the second aspect, the emulsion is cooled to a temperature T1, T1 being the pour point of the continuous phase (T cont ) and a transition temperature (T disp ) or less, and T disp >T cont However, the absolute value of T1 is not important to this disclosure, but rather, what is important is the relationship of T1 to the respective temperatures of the dispersed and continuous phases.

[0146] The term "pour point" refers to the temperature below which a substance (e.g., a liquid) loses its flow properties. It is typically defined as the lowest temperature at which a liquid (e.g., an oil) can flow out of a beaker. Pour point can be measured by standard methods known in the art. For example, ASTM D7346 "Standard Test Method for No-Pour and Pour Points of Petroleum Products and Liquid Fuels" can be used. For commercially available materials, pour points are often provided by the distributor or manufacturer.

[0147] The term "freezing point" refers to the temperature at which a substance changes state from liquid to solid under standard atmospheric pressure (1 atm). Freezing point can be measured by standard methods known in the art. For example, ASTM E794 "Standard Test Method for Thermal Analysis Melting and Crystallization Temperatures" can be used. For commercially available materials, the freezing point may be provided by the distributor or manufacturer.

[0148] The term "glass transition point" or "glass transition temperature" refers to the temperature at which a polymer structure transitions from a hard or glassy material to a soft rubbery material. This temperature can be measured by a differential scanning calorimeter according to the standard test method: ASTM E1356 "Standard Test Method for Assignment of Glass Transition Temperatures by Differential Scanning Calorimetry." For commercially available materials, the glass transition temperature may be provided by the supplier or manufacturer.

[0149] Because deformation and coagulation are believed to occur while the dispersed phase droplets are in a liquid state, it is believed that cooling the emulsion below the pour point of the dispersed phase temporarily (at least partially) changes the "colloid class" of the emulsion from an emulsion (i.e., liquid-in-liquid) to a sol (solid-in-liquid), thereby making the dispersed phase easier to handle in downstream processes.

[0150] Furthermore, the dispersed phase has a transition temperature (the transition temperature being selected from the group consisting of freezing point, glass transition temperature, and pour point) higher than the pour point of the continuous phase, meaning that the continuous phase surrounding the solidified dispersed phase can still function as a transport medium. A schematic diagram of an emulsion being cooled and temporarily converted to a sol in a cooling coil heat exchanger is shown in Figure 4(b).

[0151] FIG. 4(a) illustrates a process where the emulsion is not cooled, the continuous phase forms an emulsion with the dispersed phase droplets (in this example, microdroplets), and flow stagnation and turbulence cause undesirable coalescence and reduced yield. FIG. 4(b) then illustrates an example where the emulsion is cooled in a coil heat exchanger to a temperature below the dispersed phase transition temperature but above the continuous phase pour point, thereby allowing the continuous phase to remain mobile and transport the transitioned droplets. The exemplary embodiment of FIG. 4(b) avoids the particle coalescence, deformation, and aggregation, and the resulting loss of yield, encountered in a process such as that depicted in FIG. 4(a).

[0152] The cooling method is also not limited. The emulsion may be cooled by any means known in the art to remove heat (energy) from the system. The emulsion may also be cooled at any time before phase inversion. In various embodiments, this means that the emulsion is cooled simultaneously with the membrane emulsification process or separately from the membrane emulsification process. The emulsion may be cooled, for example, as it is formed (e.g., by a cooling means located at the membrane outlet). Alternatively, the emulsion may be cooled in a step after membrane emulsification, for example, in a cooling device separate from the membrane emulsification device. Advantageously, cooling should be performed as soon as possible after emulsification to reduce the possibility of coalescence and / or condensation of the dispersed phase droplets in the liquid state.

[0153] In various embodiments, the emulsion may be cooled by a cooling medium (e.g., water, ice, etc.) that at least partially surrounds the vessel in which the emulsion is formed. In a preferred embodiment, the vessel (e.g., a pipe) in which the emulsion is formed can have a cooling jacket that contains a cooling medium. The cooling medium is not particularly limited and includes any medium that has a lower temperature than the emulsion.

[0154] In various embodiments, the emulsion may be cooled by a cooling device connected to the membrane emulsifier. The cooling device may be a heat exchanger, such as an immersion type heat exchanger. In an exemplary embodiment, a coil heat exchanger is immersed in a cooling medium (e.g., a cold water bath), although the disclosure is not limited in this respect. It is contemplated that any type of heat exchanger may be used, such as, for example, a tube-and-shell heat exchanger, a plate-and-frame heat exchanger, or a jacketed tube. It is further contemplated that an immersion type heat exchanger may be used with another cooling medium, such as cryoprotectant, dry ice, etc., to cool the emulsion to T1.

[0155] The temperature of the antisolvent during the phase inversion is as described above.

[0156] In various embodiments of the present disclosure, the phase inversion is carried out under shear. Those skilled in the art will be aware of suitable shear conditions for phase inversion. Shear can be achieved, for example, by using an agitation vessel (e.g., a mechanical agitation vessel) or a settling vessel (e.g., a gravity settling vessel). The term "shear" is used herein to refer to an external force acting on an object or surface parallel to the inclination or plane on which the object or surface lies, where the stress tends to cause distortion.

[0157] Shear is advantageous because it increases the rate at which the continuous phase is removed from the dispersed phase droplets, thus increasing the rate of phase inversion overall. The phase inversion process is diffusion rate limited (Fickian diffusion), and shear reduces the thickness of the continuous phase layer surrounding the dispersed phase droplets, shortening the travel distance of the antisolvent molecules to the surface of the dispersed phase droplets, thereby accelerating the phase inversion process. However, shear has a negative effect on particle shape and size, and is therefore not typically used in current phase inversion processes. Currently, a mild phase inversion step is used, which allows the emulsion to be precipitated with a non-flowing antisolvent (at room temperature). Surprisingly, the dispersed phase droplets in the frozen state are relatively resistant to other methods of separation from the continuous phase, and this increased resistance allows such separation to be more efficient.

[0158] In various embodiments of the present disclosure, the phase inversion includes a filtration step. The filtration step can include, but is not limited to, mechanical or any other type of filtration (e.g., using devices known in the art such as hydrocyclones). The filtration step can also be performed when the phase inversion is performed under shear as described above. In various embodiments, a filtration medium (e.g., a filter) can be used to filter the emulsion through a poor solvent, thereby recovering the biopolymer particles. In such embodiments, the emulsion can gravitationally settle (shear) through the poor solvent into the filter while the continuous phase passes through the filter (filtrate). The frozen droplets can then be collected in the filter as a filter cake.

[0159] If not recovered as part of the phase inversion (e.g., via filtration, etc.), the biopolymer particles may be separated from the anti-solvent / continuous phase mixture, or the anti-solvent / continuous phase mixture may be removed from the particles. The method of removal is not limited. However, in various embodiments, the method of removal depends on whether the method of the present invention is operated in a batch mode or a continuous mode.

[0160] When the method of the second embodiment is carried out in batch mode, the phase inversion process can be carried out first in a closed vessel and the resulting mixture can then be transferred to a decanter vessel to reach a settling stage. Once settled, the layers can be removed sequentially from the bottom of the vessel. Typically, the order of layers can be: (1) continuous phase, (2) interfacial layer comprising wet biopolymer particles, and (3) remaining poor solvent. However, the invention is not limited in this respect, and one of ordinary skill in the art will appreciate that the order of layers will depend on their respective densities.

[0161] In various embodiments of the second aspect, the method is continuous and operates in a continuous mode, where the phase inversion process may be carried out under continuous input of emulsion and anti-solvent and continuous discharge of the multi-phase mixture into a decanter. In the decanter, there may be a steady state partition of the mixture, and there may be continuous and preferably simultaneous removal from each phase. For example, there may be continuous and preferably simultaneous removal from (1) the continuous phase, (2) the anti-solvent, and (3) the wet biopolymer particles. Of course, the order of these layers may vary, and the invention is not limited to any particular order.

[0162] Alternatively, multi-phase (eg, three-phase) mixtures can be separated using techniques known in the art, such as disc stack separators (eg, Andritz centrifuges, etc.).

[0163] To provide continuous cooling with continuous phase inversion, the cooling medium (e.g., the medium surrounding the vessel containing the emulsion or the medium used with a heat exchanger connected to a membrane emulsification unit) may need to be recycled or recirculated with a suitable device. For example, a device such as a recirculating chiller (ThermoFlex available from ThermoFisher Scientific) can be used to maintain the cooling medium at a desired temperature.

[0164] Another advantage of the method according to the second aspect is the flexibility of the sequence of events. This flexibility arises because the dispersed phase droplets can be frozen in the emulsion. Thus, in various embodiments of the present disclosure, the biopolymer particles are removed after the phase inversion as described above, or the biopolymer particles are removed during the phase inversion. The phase inversion can be followed by decantation and then the biopolymer particles can be removed from the mixture, and / or the wet particles can be mechanically filtered from the antisolvent / continuous phase / particle mixture during the phase inversion.

[0165] Alternatively, the biopolymer particles can be removed from the continuous phase prior to phase inversion. In such an embodiment, the wet frozen droplets can be removed from the sol (e.g., using filtration) and then a phase inversion can be performed to precipitate the biopolymer and form its beads / particles.

[0166] Having generally described the present disclosure above, a further understanding can be obtained by reference to the following specific illustrative examples, which are provided for illustrative purposes only and are not intended to be exhaustive or limiting unless expressly stated otherwise. EXAMPLES

[0167] Materials and Methods Preparation of cellulose solution Microcrystalline cellulose (MCC, Sigma-Aldrich®) and EmimOAc were dried in a vacuum oven at 80° C. for 1 hour to remove traces of water. Cellulose solutions were prepared at concentrations of 4, 6 or 8 wt. % MCC in EmimOAc, both with and without 8 wt. % deionized water. First, water was added to EmimOAc while stirring, followed by MCC. The mixture was shaken by hand for 1 minute, then transferred to a roller and left for 24 hours. The sample was placed in a 70° C. oven for 24 hours, stirred with a spatula, left in the oven for another 24 hours, and finally transferred to a roller again and left for 24 hours.

[0168] Coombs O'Brien et al. 1 A "control" cellulose solution was prepared (8 wt% MCC in a 70:30 mixture of DMSO:EmimOAc) according to the formulation in. This was also placed in the dryer for the same amount of time as the other samples so that all received the same heat exposure.

[0169] Example 1: Characterization of cellulose solutions Photographs of the cellulose solutions prepared according to the method detailed above were taken with an iPhone camera and optical micrographs were taken using an SP400 microscope and digital camera (Olympus). The optical micrographs are provided in FIG.

[0170] These pictures showed the appearance of the cellulose in EmimOAc solutions compared to each other and to a comparison standard containing DMSO as a co-solvent. All were clear, indicating that the cellulose was completely dissolved, which was further confirmed by the absence of particles observed under an optical microscope (Figure 5). Thus, these solutions were deemed suitable for further characterization and bead fabrication.

[0171] Further characterization was performed by viscosity measurements. Viscosity measurements were performed using a Discovery HR-3 hybrid rheometer (TA Instruments) equipped with 40 mm stainless steel parallel plates. The gap was set at 500 μm and the samples were sealed with mineral oil to prevent moisture migration. Logarithmic shear rate sweeps were performed from 0.1 to 100 s with a 10 s temperature soak prior to the measurements. -1 (10 points / decade) and viscosity is 1s -1 The measurements were recorded from the Newtonian region at 100° C., as described above.

[0172] FIG. 12 shows the 1s -1 Figure 1 shows the viscosity of each test sample at 100°C. All samples show a decrease in viscosity as expected with increasing temperature and decreasing cellulose concentration. Samples containing 8 wt% water were observed to show a significant decrease in viscosity at all cellulose concentrations. As noted above, MCC concentrations lower than 8 wt% may be able to tolerate higher water contents without precipitation, which may result in even lower viscosity. Thus, the present disclosure is not limited to a water content of 8 wt%.

[0173] The value at which the solution curve intersects the horizontal dashed line can be used as an estimate of the temperature required to achieve the same viscosity as the DMSO-containing control at room temperature, and therefore the extrusion temperature, as shown in the table below.

[0174] [Table 1]

[0175] It has been shown how the presence of water in the dispersed phase reduces the viscosity of the cellulose solution without precipitation, meaning that a viscosity similar to that of the DMSO-containing control at room temperature can be obtained at lower temperatures, which is a further advantage of the present disclosure that can contribute to providing overall environmental benefits.

[0176] Example 2: Preparation of cellulose beads Each cellulose solution prepared according to the method detailed above was divided into three samples. The first sample was used at room or ambient temperature (RT in Figure 6), the second sample was heated to 40°C, and the third sample was heated to 60°C. Once at the required temperature, each sample was placed in a 10 mL plastic syringe and fitted with a 23 gauge rounded tip stainless steel needle. The solution was immediately extruded through the needle dropwise at 0.1 mL / min through a syringe pump into water (anti-solvent). Room temperature (ambient temperature) at the time of dropping was about 15°C. An appropriate drop height for optimal sphericity was visually selected for each sample with a maximum of 60 cm. Only a few beads were produced to avoid the effects of pressure build-up. The beads were washed three times with water over three days and dried overnight at 80°C.

[0177] Photographs of the wet beads after solidification in water were taken with an iPhone camera equipped with a commercially available macro lens clip and are shown in Figure 6. Optical micrographs of the dry beads were taken with an EVOS M5000 microscope and are shown in Figure 7.

[0178] In Example 2, beads were produced by needle dropping at room temperature, 40°C, and 60°C to evaluate which solutions could be used to make spherical beads. In undesirable cases, the resulting beads may have tails or may be extruded in a continuous stream, resulting in thread-like clumps. Figures 6 and 7 show that the presence of water in the dispersed phase improves the sphericity of the beads compared to the dispersed phase without water. This improvement is especially seen at high concentrations of cellulose.

[0179] Example 3: Preparation of cellulose beads using a heated syringe and needle Further tests were carried out in Example 3 on the EmimOAc solutions containing 8 wt. % MCC and 8 wt. % water and 6 wt. % MCC and 8 wt. % water described above. These tests are intended to complement the observations made in Example 2.

[0180] The solutions were each loaded into a 50 mL glass syringe and fitted with a 23 gauge blunt-tipped stainless steel needle. A heating mat was secured around the syringe and needle and a thermocouple was attached to the thread of the metal needle. The heater was set to 70°C, allowed to cool and beads were collected at 10°C intervals using the indicated needle temperature. The solutions were extruded dropwise through the needle into water (antisolvent) at 0.05 mL / min using a syringe pump to a drop height of 13, 26 or 39 cm. The room temperature at the time of the drop was approximately 20°C. The beads were washed three times with water over three days and dried overnight at 80°C.

[0181] Photographs of the wet beads after solidification in water were taken with an iPhone camera equipped with a commercially available macro lens clip and are shown in Figures 8 and 10. Optical micrographs of the dry beads were taken with an EVOS M5000 microscope and are shown in Figures 9 and 11.

[0182] The results (Figures 8-11) show that spherical beads were obtained using 6 wt% and 8 wt% MCC solutions containing 8 wt% water in EmimOAc, respectively. These results also show how higher temperatures and drop heights favor spheronization, especially in the case of the 8 wt% solution.

[0183] conclusion Although a pure EmimOAc solution of 8 wt% MCC is indeed much more viscous than 8 wt% MCC in a 70:30 DMSO:EmimOAc mixture, Examples 1-3 show that the viscosity can be significantly reduced by including 8 wt% water and that the solution can be used in a bead dropping process to produce spherical cellulose beads. The inclusion of water in the cellulose solution reduced the viscosity, making the beads more likely to be spherical and reducing tailing. This is an important finding, since residual water in EmimOAc from the solvent recovery process is inevitable when water is used as a poor solvent. For 6 wt% and 8 wt% solutions with 8 wt% water, controlled experiments allowed us to determine the preferred parameter ranges (temperature and drop height) to obtain optimal bead sphericity.

[0184] Example 4: Membrane emulsification A dispersed phase containing 8% by weight microcrystalline cellulose and 8% by weight water in 1-ethyl-3-methylimidazolium acetate was prepared according to conventional methods known in the art. The dispersed phase had a transition temperature (e.g., freezing point) of about -5°C. An aqueous continuous phase was also prepared according to conventional methods known in the art. The pour point of the continuous phase was -15°C.

[0185] The dispersed and continuous phases were fed into a membrane emulsification unit, thereby forming an emulsion, which was then cooled to a temperature between 0°C and 11°C and then transferred to a phase inversion unit with an aqueous anti-solvent to form cellulose particles.

[0186] Cooling of the emulsion was performed using an immersed coil heat exchanger. The immersed coil heat exchanger was selected to maintain laminar flow and minimize flow disturbances as the emulsion was cooled. The coil heat exchanger contained a coiled tube of length (L) of diameter D and pitch P in a cold water bath at 0°C, which was sufficient to cool 0.5 L / min of emulsion to below 11°C. The temperature of the emulsion was monitored by a thermometer at the outlet of the coil heat exchanger. This resulted in spherical biopolymer particles.

Claims

1. A method for producing biopolymer particles, comprising extruding a dispersed phase into an anti-solvent to form particles of biopolymer, wherein the dispersed phase comprises the biopolymer in a solvent, and each of the solvent and anti-solvent comprises water.

2. 1. A method for producing biopolymer particles, comprising: a. membrane-emulsifying a dispersed phase in a continuous phase, the dispersed phase comprising the biopolymer in a solvent, by passing the dispersed phase through a membrane to form an emulsion of the biopolymer in the continuous phase; and b. Phase inversion in an antisolvent to form particles of the biopolymer. Including; The method, wherein the solvent and anti-solvent each comprise water.

3. 10. The method of claim 1, wherein forming the biopolymer particles by extruding the dispersed phase into an antisolvent comprises extruding the dispersed phase through a fluid medium by capillary extrusion.

4. 2. The method of claim 1, wherein forming the biopolymer particles by extruding the dispersed phase into an anti-solvent comprises extruding the dispersed phase through a fluid medium into a mold, and subsequently contacting the extruded dispersed phase with the anti-solvent.

5. 2. The method of claim 1, wherein the extruded dispersed phase is dropped from a height of about 1 cm to about 80 cm, preferably from a height of about 5 cm to about 70 cm, more preferably from a height of about 10 cm to about 60 cm above the surface of the anti-solvent.

6. (b) before cooling the emulsion to a temperature T １ Then, T １ is the pour point (T ｃｏｎｔ ) higher than the transition temperature (T ｄｉｓｐ ) or less, i.e., T ｃｏｎｔ <T １ ≦T ｄｉｓｐ the transition temperature is selected from the group consisting of a freezing point, a glass transition temperature, and a pour point; T ｄｉｓｐ >T ｃｏｎｔ The method of claim 2, wherein

7. For the phase inversion (b), the anti-solvent is heated to a temperature T ２ Cool to T ２ T ｄｉｓｐ The method of claim 6, wherein the temperature is lower than the reference temperature.

8. T ２ T １ The method of claim 7, wherein the

9. The method according to any one of claims 1 to 8, wherein the biopolymer is a polysaccharide, preferably the biopolymer is cellulose.

10. 10. The method of claim 9, wherein the biopolymer is cellulose and may be selected from the group consisting of virgin cellulose, recycled cellulose, pulp cellulose and microcrystalline cellulose and combinations thereof, preferably the biopolymer is microcrystalline cellulose.

11. 9. The method of any one of claims 1 to 8, wherein the biopolymer is present in the dispersed phase in an amount of from about 2% to about 12% by weight, preferably from about 4% to about 10% by weight, based on the total weight of the dispersed phase.

12. 9. The method of any one of claims 1 to 8, wherein the dispersed phase is prepared by adding the biopolymer to the solvent, the solvent comprising water before the addition of the biopolymer, or the solvent comprising water only after the addition of the biopolymer.

13. The method of any one of claims 1 to 8, wherein the solvent of the dispersed phase comprises from about 2% to about 12% by weight of water, preferably from about 4% to about 10% by weight of water.

14. The method of any one of claims 1 to 8, wherein the solvent of the dispersed phase further comprises an ionic liquid.

15. The method of any one of claims 1 to 8, wherein the anti-solvent is substantially free of organic solvents.

16. The method of any one of claims 1 to 8, wherein the anti-solvent further comprises an ionic liquid.

17. 17. The method of claim 16, wherein the ionic liquid is present in the anti-solvent at a concentration of up to about 50% by weight, preferably up to about 30% by weight, based on the total weight of the anti-solvent.

18. The method of any one of claims 1 to 8, wherein the anti-solvent consists of water.

19. The method of claim 14, wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium acetate.

20. The method according to any one of claims 1 to 8, wherein the temperature of the dispersed phase during extrusion or membrane emulsification is from about 5°C to less than about 100°C, preferably from about 20°C to about 80°C.

21. The method according to any one of claims 1 to 8, wherein the temperature of the anti-solvent is from about 5°C to about 80°C, preferably from about 15°C to about 60°C.

22. Biopolymer particles produced by the method of any one of claims 1 to 8.

23. 23. The biopolymer particles of claim 22, wherein the particles have a diameter of from about 1 μm to about 500 μm.

24. 23. The biopolymer particles of claim 22, wherein the particles have a diameter of about 0.2 mm to about 3 mm.

25. 23. The biopolymer particles of claim 22, wherein the particles have a diameter of about 1 mm to about 10 mm.

Images