Solution spinning of protein-cellulosic blend fibers

Abstract

Provided are compositions and methods related to cellulosic materials combined with protein powder and that are subjected to aging conditions under temperature during a process that includes wet spinning to produce fibers. The method yields mechanically strong fibers.

Description

Attorney Docket No.: 074339.00278 SOLUTION SPINNING OF PROTEIN-CELLULOSIC BLEND FIBERS CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 518,522, filed August 9, 2023, the entire disclosure of which is incorporated herein by reference. BACKGROUND

[0002] The production of regenerated protein fibers achieved commercial success through the innovative work of Italian chemist Antonio Ferretti in 1935. SNIA Viscosa, based in Milan, introduced the world's first commercially produced protein fibers called Lanital™ in 1936, which were derived from milk casein. This was followed by Courtaulds in Great Britain (Caslen and Fibrolan casein fibers) and Enka in the Netherlands, Germany, and the United States (Aralac and R-53 casein fibers). To enhance the wet properties of the fibers, they were treated with formaldehyde or aluminum salts to create cross-links between the proteins within the fibers. In 1945, SNIA Viscosa replaced Lanital™ fibers with Merinova™ casein fibers, which exhibited improved properties compared to Lanital™ fibers.[1]

[0003] From the mid-20th century until the 1960s, vegetable-based regenerated protein fibers were also produced in addition to casein fibers. These included Ardil fibers, produced by the British ICI Company, derived from oilseed peanuts proteins, and Vicara fibers, produced by the American Virginia-Carolina Corporation, made from corn zein proteins. Fabrics made from regenerated protein fibers were highly desirable, possessing softness, luster, resilience, a pleasing hand feel, and thermal resistance. They served as substitutes for wool or silk and gained popularity among European fashion designers.[1]However, the advent of cheaper synthetic fibers with superior mechanical properties in the early 1960s significantly impacted the commercial production of regenerated protein fibers. Consequently, their production was discontinued entirely in the mid-1960s.[1]

[0004] Today, the increasing global population demands higher quantities of textiles. Worldwide fiber production has increased, reaching 78 million tons in 2010, including approximately one million tons of wool and 0.15 million tons of silk. Wool and silk remain expensive fibers, with selling prices ranging from approximately €14-23 / kg and €28-40 / kg, respectively.[1]

[0005] Polymer blending plays a crucial role as a cost-effective alternative to graft copolymerization and developing new polymers, which can be time-consuming andexpensive. Extensive research has been dedicated to blending different polymers, aiming to create innovative products that exhibit desirable properties from each component.

[0006] Fibers derived from cellulose-protein solutions have gained attention as innovative fibers, primarily due to their unique physical structure and exceptional properties that set them apart from conventional regenerated fibers. Developing effective solvents for protein solutions is essential for various applications in the textile and materials industries. Solvents are important in dissolving and transforming proteins into usable forms such as filaments and fibers. However, identifying and selecting solvents that meet the necessary criteria, including feasibility, cost-effectiveness, and compatibility with spinning technologies, remains a significant challenge.

[0007] In 1969, Johnson disclosed use of NMMO (N-Methylmorpholine-N-Oxide), focusing on its ability to dissolve cellulose and other natural polymers[3]. The natural polymers included wool, silk, hair, feathers, β-amylose, casein, zein, gelatin, gum arabic, and lignin. In a study by Firgo et al. (1998) from Lenzing AG, gelatin was incorporated into an NMMO-water-cellulose solution to regulate fiber fibrillation[4]. Similarly, Stall and Turbak (1999) utilized gelatin to decrease fibrillation by causing to control the rapid precipitation of cellulose from NMMO solution[5]. However, as highlighted by Schuster et al. (2012), the presence of gelatin and other structural proteins such as collagen, milk proteins (caseins, whey proteins) resulted in low efficiencies during experimental spinning processes due to the hydrolytic activity of the solvent[6]. Consequently, the degradation products contaminated the coagulation bath, posing challenges for solvent recovery.

[0008] Heinemann and Taeger (2000) described a blend of cellulose and silk fibroin fibers produced using the Lyocell process[7]. Subsequently, they revealed that silk fibroin does not fully dissolve in NMMO without including an organic solvent such as DMSO, resulting in the absence of a fiber-forming solution. However, the addition of DMSO in the Lyocell process not only negatively impacts the solubility of cellulose but also complicates the recovery of the solvent.

[0009] Yao et al. (2005) conducted a study in which they utilized an ionic liquid ([BMIM]Cl) to produce blend fibers of cellulose and silk fibroin, with a protein ratio of up to 40%[8]. Despite varying the composition of the coagulation bath, they observed a protein loss of at least 21% compared to the initial amount added to the solid dope[9]. Similarly, when keratin was blended with cellulose in solutions prepared in ionic liquids, the resulting fibers also experienced protein leeching during regeneration[10,11]. This leads to contamination of the coagulation bath, thereby complicating the recovery of the solvent and increasing theassociated costs. Thus, there is an ongoing and unmet need for improved protein-cellulosic blend fibers. The present disclosure is pertinent to this need. BRIEF SUMMARY

[0010] The present disclosure provided compositions and methods for using a process that modifies cellulose and protein mixtures to produced regenerated fibers. In an example, a method comprises: i) combining a cellulosic material and protein with an ionic liquid; ii) subjecting the cellulosic material, protein and the ionic liquid to a heat treatment, wherein the heat treatment optionally comprises a temperature of approximately 90°C, and wherein the heat treatment is performed for a period of time that is optionally approximately 2-4 hours. The mixture of ii) is held at a temperature that is optionally approximately 60°C for a period of time that is optionally 12-48 hours. This step can be performed in the absence of mixing. Once the mixture of ii) is aged as in the preceding step or steps, the disclosure includes wet spinning the cellulosic material and the protein mixture to thereby produce the regenerated fibers. BRIEF DESCRIPTION OF THE FIGURES

[0011] FIG.1A. The top of FIG.1A shows a representative laboratory-scale solution spinning setup and process. The setup shows, starting on the left with the dope and pump, a coagulation container, two washing baths, heated rollers, and a winder. The bottom of FIG. 1A shows representative photographs that correspond to the top of FIG.1A.

[0012] FIG.1B shows representative photographs of protein-cellulose blend fibers produced using the solution process shown in FIG.1A. The process shown in FIG.1A and the results shown in FIG.1B were produced according to the representative processes and reagents shown in Table 1 (provided as FIG 2.)

[0013] FIG.1C provides representative graphs of mechanical properties of the cellulosic fibers (stress as MPa, and percentage strain).

[0014] FIG.2 provides Table 1, showing, from left column to the right, representative Dope concentrations, Protein concentrations, Solvent, Mixing conditions, Aging conditions, Spinning temperature, Pump speed, Spinneret hole size, Coagulation bath conditions, Washing baths conditions, Washing bath temperatures and Roller speeds, and Drying temperatures. The cellulose used for each protein type shown in the left column is cellulose triacetate.DETAILED DESCRIPTION

[0015] Unless defined otherwise herein, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0016] Every numerical range given throughout this specification includes its upper and lower values, as well as every narrower numerical range that falls within it, as if such narrower numerical ranges were all expressly written herein.

[0017] Although claimed subject matter will be described in terms of certain examples, other examples, including examples that do not provide all of the benefits and features set forth herein, are also within the scope of this disclosure. The steps of the method described in the various examples and examples disclosed herein are sufficient to carry out the methods of the present invention. Thus, in an example, the method consists essentially of a combination of the steps of the methods disclosed herein. In another example, the method consists of such steps.

[0018] As used in the specification and the appended claims, the singular forms “a” "and” and “the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another example includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about” or “approximately” it will be understood that the particular value forms another example. The term “about” and “approximately” in relation to a numerical value encompass variations of + / -10%, + / - 5%, or + / - 1%.

[0019] This disclosure includes all materials, material combinations, solutions, times, temperatures, and mechanical properties described herein. The disclosure includes all steps individually and in combination, including but not necessarily performing all some or described steps sequentially. The disclosure includes all materials produced by the described methods, and articles of manufacture that incorporate a described material produced by a described method.

[0020] The disclosure relates to use of cellulosic materials combined with a protein component and a solvent / ionic liquid that are subjected to aging conditions under temperature. By use of a wet spinning process of a cellulose and protein blend solution, the described methods yields mechanically strong fibers comprising a cellulose and protein blend solution. Thus, the disclosure provides methods for making regenerated cellulosic fibers (alsoreferred to as manmade cellulosic fibers) and the regenerated fibers themselves. Accordingly, in an aspect, the disclosure provides for use of combinations of proteins and cellulose. The described composite materials based on compatible polysaccharides and proteins hold promising potential as textile materials. These composites can offer unique properties and functionalities that surpass those of conventional textiles, enabling the development of sustainable and high-performance textile products. By leveraging the properties of cellulose, and proteins, the disclosure can provide eco-friendly fabrics that reduce environmental impact while maintaining the desired functionality and aesthetics demanded by the textile industry.

[0021] In examples, the protein component of a described fiber is obtained from any suitable source, subject to a proviso described below. In examples, a protein component used in a method and incorporated into a described fiber is obtained from a plant or plant product. In examples, the plant or plant product has a relatively high protein content. In examples, the source of the protein is any of beans, legumes, lentils, nuts, seeds, oats, broccoli, Brussels sprouts, peas including but not limited to green peas and chickpeas, quinoa, wild rice, or edamame. In examples, a protein component used in a method and incorporated into a described fiber is obtained from a microbial source, including but not necessarily any type of yeast or bacteria. The yeast or bacteria may be engineered to produce a specific protein. In examples, a protein component used in a method and incorporated into a described fiber may be obtained from a non-human animal. As such, the protein may be obtained or derived from muscle or other animal parts, such as wool. Any protein component may be used in an extracted and / or purified form. Any protein may be provided for use in a described method in a granular form, such as a powder.

[0022] In examples, the cellulosic material used in a described method and incorporated into described fibers comprises any chain length. In examples, the cellulosic material has a chain length (i.e., monomeric units) that is 300 to 10,00 units, In examples, the cellulosic material has a chain length of 300 and 1700 units. In examples, the cellulosic material comprises cellulose I, with structures Iα and Iβ, or a combination thereof. In examples, the cellulosic material comprises cellulose II. In examples, the cellulosic material comprises cellulose III cellulose IV. In examples, the cellulosic material is obtained from any suitable source, including but not limited to paper or cardboard. In examples, the cellulosic material is obtained from any plant, including, but not limited to monocots and dicots. In examples, the cellulosic materials is obtained from deciduous trees, or coniferous trees. In examples, the cellulosic material is obtained from plant parts, such as leaves, flowers,branches, fruit, kernels, ears, cobs, husks, stalks, roots, or pulp. In examples, the cellulosic material is obtained from a plant hybrid, such as Eucalyptus urograndis. In examples, the cellulose is derived from a fungal, algal, or bacterial source. In an example, the cellulosic material comprises pullulan. In examples, the cellulosic material is cellulose triacetate or methyl cellulose.

[0023] In examples, a fiber produced according to this disclosure comprises a cellulosic component that comprises or consists of any single, or any combination, of the foregoing types of cellulosic material.

[0024] In examples, any described process and fibers as described herein may be free of any one or combination of poly(vinyl chloride) (PVC), polypropylene (PP), poly(ethylene- co-vinyl acetate) (EVA), poly(ethylene terephthalate) (PET), Polylactic acid (PLA), hydroxypropyl methylcellulose (HPMC), nylon, linear low-density polyethylene (LLDPE), or ethylene vinyl alcohol (EVOH). In examples, any described process and fibers as described herein may be free of any polypeptides which comprise alternating repeats of crystallite- forming subsequences and amorphous subsequences. In examples, the described fibers do not exhibit a triboelectric effect.

[0025] In examples, a fiber produced according to this disclosure consists essentially of (i.e., it includes only trace amounts of solvent or other components), or consists of cellulosic material and protein as described herein. In examples, fibers produced according to the present disclosure may be incorporated into any article of manufacture, non-limiting examples of which include textiles. In examples, the disclosure includes a fiber and a plurality of fibers produced by a described method.

[0026] In examples, the fibers are produced using at least in part a wet spinning process. Wet spinning processes and reagents used to perform the method generally are known in the art, and can be adapted to produce the described fibers by the skilled artisan when given the benefit of the present disclosure. Wet spinning is performed using an ionic liquid (IL) as a type of solvent. In non-limiting examples, an ionic liquid used in a described method is a so-called “room temperature” IL. In examples, the IL is 1-ethyl-3- methylimidazolium acetate (EMIMOc) or dimethyl sulfoxide (DMSO). In examples, the IL comprises any of N-methylmorpholine N-oxide monohydrate (NMMO ^H2O), Dialkylimidazolium-based ILs, including [Amim]Cl, [Bmim]Cl, [Emim]Cl, [Emim]OAc, [Bmim]OAc, and 1-ethyl-3-methylimidazolium diethylphosphate ([Emim][(EtO)2PO2]), and ammonium-based ILs such as tetrabutylammonium acetate (TBAA) / DMSO, and [DBNH]OA. In examples, the IL is 1-allyl-3-methylimidazolium chloride ([Amim]Cl); 1-allyl-2,3-dimethylimidazolium bromide ([ADmim]Br); 1-allyl-3-methylimidazolium formate ([Amim]HCOO); 1-butyl-3-methylimidazolium aminoethanoate ([Bmim][H2NCH2COO]); 1- butyl-3-methylimidazolium benzoate ([Bmim][PhCO2]); 1-butyl-3-methylimidazolium chloride ([Bmim]Cl); 1-butyl-3-methylimidazolium formate ([Bmim][HCOO]); 1-butyl-3- methylimidazolium acetate([Bmim]OAc); 1-ethyl-3-methylimidazolium acetate ([Emim]OAc); 1-ethyl-3-methylimidazolium methylphosphonate [Emim][(MeO)(H)PO2]; 1- ethyl-3-methylimidazolium diethylphosphate ([Emim][Et2PO4]); N,N-dimethyl-2- methoxyethylammonium acetate ([(Me)2(MeOEt)NH]OAc); Triethyl-2-(2- methoxyethoxy)ethanammonium acetate ([Me(OEt)3-Et3N]OAc); 3-methyl-N- butylpyridinium chloride ([C1NC4Py]Cl); 1-ethyl-3-methylimidazolium Levulinate ([Emim]Lev); 1-butil-3-methylimidazolium Levulinate ([Bmim]Lev); 1,5- diazabicyclo[4.3.0]non-5-ene acetate [DBNH]OAc; 1,5-diazabicyclo[4.3.0]non-5-ene propionate [DBNH][CO2Et]; 1,8-diazabicyclo[5.4.0]undec-7-ene propionate [DBUH][CO2Et]; 1,1,3,3-tetramethylguanidine propionate:1-ethyl-3-methylimidazolium acetate 1:1 [TMGH][CO2Et]: [Emim]OAc; 1,1,3,3-tetramethylguanidine acetate [TMG]OAc; 1,1,3,3-tetramethylguanidine propionate [TMG][CO2Et]; 1,1,3,3-tetramethylguanidine acetate [TMG]OAc; 1,8-diazabicyclo[ 5.4.0]undec-7-ene acetate [DBUH]OAc; 1,8- diazabicyclo[ 5.4.0]undec-7-ene propionate [DBUH][CO2Et]; 1,8-diazabicyclo[ 5.4.0]undec- 7-ene butanoate [DBUH][CO2Pr]; 1,8-diazabicyclo[ 5.4.0]undec-7-ene hexanoate [DBUH][CO2Pen]; 1,8-diazabicyclo[ 5.4.0]undec-7-ene octanoate [DBUH][CO2Ept]; or 1,8- diazabicyclo[ 5.4.0]undec-7-ene acetate [DBUH]OAc.

[0027] Non-limiting examples of the starting materials and methods, reagents, temperatures and time periods for processing the materials are shown in FIG.2, which provides Table 1. In examples the cellulosic material comprises cellulose derived from plant matter or bacteria. In examples, the protein comprises pea protein, soy protein, wool protein, or yeast protein. In representative examples, as shown in Table 1 of FIG.2, the pea protein and the cellulose are present as approximately 9-15% of the weight of a combination of the cellulose, the pea protein, and the solvent / ionic liquid. In an example, pea protein is present as approximately 20%-60% of the weight of a combination of the cellulose and the protein. In an example, soy protein and the cellulose are present as approximately 9% of the weight of a combination of the cellulose, the soy protein, and the solvent / ionic liquid. In an example, the soy protein is present as approximately 20% of the weight of the combination of the soy protein and the cellulose. In an example, the wool protein and the cellulose are present as approximately 14% of the weight of a combination of the cellulose, the pea protein, and thesolvent / ionic liquid. In an example, the wool protein is present as approximately 50% of the weight of a combination of the cellulose and the wool protein. In an example, the yeast protein and the cellulose are present as approximately 13% of the weight of a combination of the cellulose, the pea protein, and the solvent / ionic liquid. In an example, the yeast protein is present as approximately 50% of the weight of a combination of the cellulose and the yeast protein.

[0028] As will be apparent from Table 1 in FIG.2, the disclosure includes aging of the described materials, prior to and optionally after fiber production. In an example, aging comprises a heat treatment, which comprises exposure of the materials to a temperature of approximately 90°C and a period of time that is approximately 2-4 hours. In example, the cellulosic material, the protein and the solvent / ionic liquid is performed at a temperature that is approximately 60°C for a period of time that is approximately 12-48 hours. In an example, the disclosure provides regenerated fibers produced according to a described method.

[0029] The following Example provides representative aspects of the disclosure, which are not intended to be limiting.

[0030] FIG.1A – FIG.1C illustrat a wet spinning process of the disclosure, which uses a dope made of cellulose with varying protein concentrations. The cellulose and protein solutions were mixed evenly, showing no signs of phase separation. To provide for the production of strong fibers, we adjusted the solid dope content between 9% and 14% w / v depending on the solution’s protein type and resulting viscosity. Table 1 contains the spinning parameters and dope concentrations for pea, soybean, yeast, and wool protein extracts. The described spinning approach produces consistent continuous filaments, allowing for sub-kg-scale production and precise fiber sampling.

[0031] Polymer ageing can occur through physical ageing without any chemical reaction, as well as through chemical changes like crosslinking during the curing of a thermoset. Polymer ageing can also occur through thermal conditioning at high temperatures and photochemical ageing during weathering. For the described protein-cellulose mixture, the samples were kept in in organic solvents (such as DMSO, ionic liquid, or 4- methylmorpholine 4-oxide (NMMO) at 60 °C to provide both physical and thermal ageing.

[0032] Analysis of mechanical properties of the fibers using tensile tests following ASTM standards were performed. The diameters of the cellulosic fibers were approximately 25 ^m. Since the diameter of as-spun cellulose fibers was 55 ^m, a draw ratio ofapproximately 2.0 was calculated. The representative tensile test curves of fibers are shown in FIG.1C.

[0033] Although the present disclosure has been described with respect to one or more particular examples and / or examples, it will be understood that other examples and / or examples of the present disclosure may be made without departing from the scope of the present disclosure.

[0034] The following reference listing is not an indication that any particular reference is material to patentability.

[0035] References: 1. Rijavec T, Zupin Ž. Soybean protein fibres (SPF). INTECH Open Access Publisher; 2011. 2. Wawro D, Stęplewski W. Producing continuous cellulose fibres modified with plant proteins. Fibres & Textiles in Eastern Europe.2010. 3. Johnson DL (1969) Compounds dissolved in cyclic amine oxides. US Patent 3,447,939, 3 Jun 1969. 4. Firgo H, Seidl S, Bartsch P, Koll B, Mulleder E (1998) Cellulose fibre. US Patent 5,795,522, 18 Aug 1998. 5. Stall AD, Turbak AF (1999) Slowing and controlling the rapid precipitation of cellulose from tertiary amine oxide solutions by adding a water soluble polymer having a high molecular weight. US Patent 5,951,933, 14 Sep 1999. 6. Schuster KC, Rous MA, Hainbucher KM, Richardt D, Redlinger S, Firgo H, Kroner G (2012) Functionalized molded cellulose body and method for producing the same. US Patent 13 / 519,369.20 Dec 2012. 7. Heinemann K, Taeger E (2000) Production of solutions of fibrillar proteins, especially silk, comprises dissolving the protein in N-methylmorpholine N-oxide. DE Patent 19,841,649, 27 Apr 2000. 8. Yao Y, Zhang E, Xia X, Yu J, Wu K, Zhang Y, Wang H (2015) Morphology and properties of cellulose / silk fibroin blend fiber prepared with 1-butyl-3- methylimidazolium chloride as solvent. Cellulose 22(1):625–635 9. Yao, Y., Yan, Z., Li, Z., Yi, H., Zhang, Y., & Wang, H. (2018). Effect of Coagulants on Phase Morphology and Property of Cellulose / Silk Fibroin Blend Fiber. In AdvancedFunctional Materials: Proceedings of Chinese Materials Conference 2017 18th (pp. 891-899). Springer Singapore. Zahra, H., Selinger, J., Sawada, D., Ogawa, Y., Orelma, H., Ma, Y., ... & Hummel, M. (2022). Evaluation of Keratin–Cellulose Blend Fibers as Precursors for Carbon Fibers. ACS Sustainable Chemistry & Engineering, 10(26), 8314-8325. Kammiovirta, K., Jääskeläinen, A. S., Kuutti, L., Holopainen-Mantila, U., Paananen, A., Suurnäkki, A., & Orelma, H. (2016). Keratin-reinforced cellulose filaments from ionic liquid solutions. RSC advances, 6(91), 88797-88806.

Claims

What is claimed is:

1. A method for producing regenerated fibers, the method comprising: i) combining a cellulosic material and protein with an ionic liquid; ii) subjecting the cellulosic material, protein and the ionic liquid to a heat treatment, wherein the heat treatment optionally comprises a temperature of approximately 90°C, and wherein the heat treatment is performed for a period of time that is optionally approximately 2-4 hours; iii) holding the cellulosic material, protein and the ionic liquid of ii) at a temperature that is optionally approximately 60°C for a period of time that is optionally 12-48 hours; and wherein the holding is performed in the absence of mixing; and iv) wet spinning the cellulosic material, protein and the optionally the ionic liquid of iii) to thereby produce the regenerated fibers.

2. The method of claim 1, wherein the cellulosic material comprises cellulose derived from plant matter or bacteria.

3. The method of claim 2, wherein the cellulose is derived from plant matter.

4. The method of claim 3, wherein the protein comprises pea protein, soy protein, wool protein, or yeast protein.

5. The method of claim 4, wherein the protein is the pea protein, and wherein the pea protein and the cellulose are present as approximately 9-15% of the weight of a combination of the cellulose, the pea protein, and the ionic liquid.

6. The method of claim 5, wherein the pea protein is present as approximately 20%-60% of the weight of a combination of the cellulose and the protein.

7. The method of claim 4, wherein the protein is the soy protein, and wherein the soy protein and the cellulose are present as approximately 9% of the weight of a combination of the cellulose, the soy protein, and the ionic liquid.

8. The method of claim 7, wherein the soy protein is present as approximately 20% of the weight of the combination of the soy protein and the cellulose.

9. The method of claim 4, wherein the protein is the wool protein, and wherein the wool protein and the cellulose are present as approximately 14% of the weight of a combination of the cellulose, the pea protein, and the ionic liquid.

10. The method of claim 9, wherein the wool protein is present as approximately 50% of the weight of a combination of the cellulose and the wool protein.

11. The method of claim 4, wherein the protein is the yeast protein, and wherein the yeast protein and the cellulose are present as approximately 13% of the weight of a combination of the cellulose, the pea protein, and the ionic liquid.

12. The method of claim 11, wherein the yeast protein is present as approximately 50% of the weight of a combination of the cellulose and the yeast protein.

13. The method of claim 1, wherein the heat treatment comprises a temperature of approximately 90°C and a period of time that is approximately 2-4 hours; and wherein the holding the cellulosic material, the protein and the solvent is performed at a temperature that is approximately 60°C for a period of time that is approximately 12-48 hours.

14. The method of any one of claims 1–13, wherein the ionic liquid is 1-ethyl-3- methylimidazolium acetate (EMIMOc) or Dimethylsulfoxide (DMSO).

15. Regenerated fibers produced according to the method of claim 14.

16. The regenerated fibers of claim 15, wherein the cellulosic material comprises cellulose. 17 The regenerated fibers of claim 16, wherein the cellulose is derived from plant matter.

18. The regenerated fibers of claim 17, wherein the protein is pea protein.

19. The regenerated fibers of claim 17, wherein the protein is soy protein.

20. The regenerated fibers of claim 17, wherein the protein is wool protein.

21. The regenerated fibers of claim 17, wherein the protein is yeast protein.

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