SOY alginate fibers

Abstract

The present invention provides fibers and methods to produce fibers composed of soy protein isolate (SPI) and alginate (Alg.) that allow for the integration of colored recombinant proteins to generate inherently-colored fibers.

Description

[0001] Attorney Docket No.: WERE-002 / 02WO 39529 / 20 SOY ALGINATE FIBERS FIELD OF DISCLOSURE This disclosure relates to textile fibers. BACKGROUND The fashion industry is one of the biggest contributors to climate change, producing 1.2 billion tons of CO2 emissions per year and the single largest source of microplastic pollution globally. The linear take-make-waste production model makes the fashion industry responsible for 10% of global CO2emissions annually. The textile industry is also one of the most chemically intensive and ecotoxic industries on earth and the second largest source of industrial water pollution after agriculture, both in terms of the volume generated and toxicity of effluents. Textile production is responsible for the majority of microplastic pollution globally (35%), with machine washing of synthetic textiles responsible for 23% of micro plastic pollution in the ocean. Textile dyeing and finishing accounts for 20% of global water waste, including the consumption of half a trillion gallons of freshwater to dye textiles alone. The market and the prospect of future life on Earth demands that consumer goods be bio-derived, degradable, and produced by low pollution, low carbon-footprint process. With 15% of the industry’s carbon footprint coming from conventional fiber production and 36% from the dyeing and finishing phase, current alternatives to conventional fibers such as recycled polyester, organic cotton, and man-made cellulose continue to present environmental shortcomings. These fibers are still dependent on water and land intensive agricultural practices, intensive chemical processing, and the use of synthetic dyes. They also continue shed microplastics and leach toxic dyes and finishes into the environment. Another alternative, biosynthentic and regenerated protein-based fibers, faces challenges in textile utility, ranging from poor mechanical properties to high thermal shrinkage (e.g. recombinant spider silk). Regenerated bulk protein fibers suffer from poor tensile partially due to lack of molecular entanglement after extrusion into fiber form. This issue is caused by several issues associated with fiber manufacturing from bulk protein feedstocks. First, bulk protein mixtures contain low molecular weight subunits which do not easily entangle. Second, designing processing methods to denature the secondary and tertiary Attorney Docket No.: WERE-002 / 02WO 39529 / 20 protein structure is difficult. Finally, it is difficult to design a solution spinning process that does not re-fold the protein before coagulation even if it was successfully denatured. For many bulk protein fiber materials, such as soy proteins and milk proteins, highly successful denaturing processes still yield weak fibers. Moreover, the potential environmental performance benefits of biofibers fabricated from bulk proteins such as soy protein isolate (SPI) is offset by the use of reagents with high toxicity and carbon footprints in processing the biopolymer (“dope”), and fiber coagulation and crosslinking baths, including urea, formaldehyde and glutaraldehyde. SUMMARY The present invention provides fibers and methods to produce fibers composed of soy protein isolate (SPI) and alginate (Alg.) that allow for the integration of colored recombinant proteins to generate inherently-colored fibers. Fibers of the invention harness microbial biosynthesis of designer proteins, green chemistry processing, and biopolymers that can be derived from waste streams to engineer compostable textile fibers with DNA-programmed color. Advantageously, the invention provides a colored, fully biomacromolecule-based fiber spun without the use of solvents other than water, without a separate dyeing step, and using only environmentally-friendly reagents. This process is compatible with currently industrially- relevant textile equipment, including wet spinning equipment. Aspects of the invention provide a method of preparing fibers that comprises preparing a mixture comprising soy protein isolate and water. A colored recombinant protein is added to the mixture. Notably, alginate is then added to the mixture comprising SPI, water, and the colored recombinant protein. This method produces a fiber with coloring incorporated into the structure of the fibers by being covalently bound into the bulk fiber material, without the need for subsequent dying. The method may further comprise the step of mixing a denaturant into the mixture prior to the step of providing a colored recombinant protein into the mixture. Advantageously, the denaturant may be a denaturant with a limited environmental impact, for example sodium dodecyl sulfate (SDS). The denaturant may be mixed into the mixture at alkaline conditions. Alkaline conditions may be produced by adding a base to the mixture until the desired pH is achieved, for example at least a pH of 10. Any base may be used, for example the base may be Attorney Docket No.: WERE-002 / 02WO 39529 / 20 selected from the group comprising sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg(OH)2), calcium hydroxide (Ca(OH)2), aluminum hydroxide, ammonia. The mass ratio of alginate to SPI may be between 1:2 and 2:1. For example, the mass ratio may be 1:1 or 1:2 alginate to SPI. In preferred aspects, the mass ratio is 1:2 alginate to SPI. Advantageously, the colored recombinant protein may comprise less than 1% of the fiber mass. In the step of preparing the mixture the SPI may be about 10-25 wt% of the mixture. The ratio of SPI to a subsequence denaturant in the mixture may be about 10:3. This provides that allows for water to not only be the primary solvent, but the only solvent. The present invention also provides the advantage of providing a rapid and efficient process for fiber production. For example, the mixing step may be completed within 30 minutes. The providing step may be conducted as quickly as 12 hours after the mixing step is completed. Aspects of the invention further comprise the step of adding hydrochloric acid to the mixture to neutralize the pH of the mixture prior to the step of providing a colored recombinant protein to the mixture. Aspects of the invention benefit from the insight that covalently linking glutamine residues to lysine residues increases the molecular weight of soy protein globulins. Prior to the present invention, enhancing the molecular weight of proteins was unexplored as a route to enhance fiber strength. Aspects of the invention, therefore, comprise the step of covalently linking glutamine residues to lysine residues. For example, methods may comprise adding transglutaminase to the mixture prior to adding alginate to the mixture, thereby covalently linking glutamine residues to lysine residues. The step of covalently linking residues may comprise adding transglutaminase at room temperate followed by heating the solution to above 50 °C to deactivate the transglutaminase. For example, the step of covalently linking residues may comprise heating the solution to up to 90°C. Advantageously, fibers of the invention have improved viscosity that allows for enhanced molecular entanglement for protein solution. This allows for the wet spinning of fibers. Aspects of the invention, therefore, also include the step of wet spinning the mixture using a hand-held syringe, filament tow, or multifilament spinneret. The step of wet spinning Attorney Docket No.: WERE-002 / 02WO 39529 / 20 the mixture may comprise wet spinning the mixture into a coagulation bath. The coagulation bath may comprise an acid and / or a salt. The acid may be selected from the group comprising hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3), acetic acid (HC2H3O2), carbonic acid (H2CO3), citric acid (C6H8O7), and acid (C6H4(OCOCH3)CO2H). The salt may be any organic or inorganic salt, e.g. the coagulation bath may comprise 0.25-10% CaCl2 and / or 0.25-3% HCl. In aspects of the invention the pH of the coagulation bath is in the pH range 2.8-5.8. The step of wet spinning the mixture in a coagulation bath may further comprise the step of wet spinning the mixture in a second coagulation bath. The second coagulation bath may be substantiall similar to or different from the first coagulation bath. For example, the second second coagulation bath may also have a pH range 2.8-5.8. For example, the pH of the first and / or second coagulation bath is adjusted to a value between 2.8 and 5.8 by a weak or strong acid, or by a buffer such as sodium citrate. Methods of the invention provide for the preparation of fibers that do not use environmentally harmful denaturants, for example urea, thiols, or glutaraldehyde. Alginate used in methods of the invention may be in any form. For example, the alginate may be in the form of calcium alginate or alginic sodium salt. The alginate may be provided in a mixture with water at 5 wt%. Methods of the invention also allow for temperature-controlled variation is the viscosity of the mixture during fiber formation, allowing for control of the tenacity and elongation at break % of the fiber. For example, after adding transglutaminase to the solution, the solution may be heated to denature transglutaminase, thereby controlling viscosity of the solution. For example, the solution may be heated within 10 hours of adding transglutaminase. Preferably, the solution may be heated within 5 hours of adding transglutaminase. The solution may be heated up to between 70-90°C. The solution may be heated to an elevated temperate for at least 30 minutes. Methods of the invention may produce a fiber comprising a tenacity greater than 5 cN / tex. Methods of the invention may produce a fiber comprising an elongation at break % greater than 5%. Aspects of the invention provide a high molecular weight fiber, for example as produced by methods of the invention. The fiber comprises soy protein isolate (SPI) Attorney Docket No.: WERE-002 / 02WO 39529 / 20 comprising glutamine residues covalently linked to lysine residues, alginate, and a colored recombinant protein. As described above, the glutamine residues may be linked to lysine residues by transglutaminase. Glutamine residues may also be linked to lysine residues by physical entrapment. The fiber may comprise advantageous properties in compared to biosynthetic fibers, including a tenacity greater than 5 N / tex and / or an elongation at break % greater than 5%. Advantageously, because the recombinant proteins are incorporated into the molecular structure of the fibers, the high molecular weight fibers of the invention also retain color fastness, resisting change in its color characteristics or transfer of its recombinant colored proteins, including lightfastness, was fastness, and rub fastness. For example, the color of the fiber may remain unfaded after 24 hours in water. The color of the fiber may remain unfaded after one week in ambient light. Fibers of the invention may remain unfaded after abrasion is applied to the fabric. Remaining unfaded in the fiber may define a loss of less than 80%, 85%, 90%, 95%, 96%, 97%, 98%, or 99% of the color of the fiber. Aspects of the invention also provide fibers and method of preparing fibers that comprise soy protein isolate and alginate, without a recombinant colored protein. For example, methods may comprise preparing a mixture comprising soy protein isolate and water. Alginate is then added to the mixture comprising SPI and water. This method produces a fiber without the need for subsequent dying. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 is a graph of solution viscosity following the addition of transglutaminase. FIG.2 is a table of mechanical properties of fibers of the invention. FIG.3A and FIG.3B are graphs of the properties of fibers of the invention. FIG.4 shows colored fibers of the invention. FIG.5 shows a summary of the impact of using transglutaminase on the resulting color of fibers. FIG.6 shows dip-dyed fibers of the invention. FIG.7A and FIB 7B are image multi-filament non-colored fibers of the invention. FIG.8 is a table of multi-filament spun fibers of the invention. FIG.9 is a table of tensile testing results of monofilament fibers. Attorney Docket No.: WERE-002 / 02WO 39529 / 20 FIG.10 is an image of monofilament fiber spools of the invention. FIG.11 is an image of multifilament fiber spools of the invention. FIG.12 is an image of multifilament fibers of the invention. FIG.13A-B are images of Western Blot and SDS-PAGE showing cross-linking in fibers of the invention. DETAILED DESCRIPTION The present invention provides fibers and methods to produce fibers composed of soy protein isolate (SPI) and calcium alginate (Alg.) that allow for the integration of colored recombinant proteins to generate inherently-colored fibers. Fibers of the invention harness microbial biosynthesis of designer proteins, green chemistry processing, and biopolymers that can be derived from waste streams to engineer compostable textile fibers with DNA- programmed color. These fibers address three of the industry’s largest areas of impact: 1) greenhouse gas emissions, 2) toxicity and water usage from the dyeing and finishing phase; and 3) microplastic pollution from petroleum-derived fibers. Advantageously, the invention provides a colored, fully biomacromolecule-based fiber spun without the use of solvents other than water, without a separate dyeing step, and using only environmentally-friendly reagents. This process is compatible with currently industrially- relevant textile equipment, including wet spinning equipment. Inherent color and function provided by protein structure allow fibers of the invention to eliminate petrochemicals and water and chemical intensive textile dyeing and finishing processes from the fashion supply chain. The climate change mitigation potential of biofabrication processes and products is estimated at 1-2.5 billion tons CO2-eq. per year by 2030. Greater carbon offsets may be achieved if bioengineering is used to disrupt conventional textile manufacturing, which is currently expected to constitute 25% of the global carbon budget by 2050. Fibers of the invention are designed to be biodegradable by and non-toxic to microorganisms in the environment, for safe degradation at end of product life. As part of this circular process, healthy soil is produced and acts as an important climate regulator, with the potential to mitigate an additional 23.8 Gt of CO2-eq. per year globally. Transglutamase Transglutaminase enzymes include proteins which facilitate the formation of an isopeptide bond between a carboxamide group of a glutamine and an amino group of a lysine Attorney Docket No.: WERE-002 / 02WO 39529 / 20 in a peptide. A transglutaminase may be isolated from any source, for example, a bacterial or mammalian cell. A transglutaminase curing bath may be used in aspects of the invention, comprising a solution that contains transglutaminase for the purpose of crosslinking molecules that are exposed to the solution. For example, transglutaminase may be a “meat glue” formulation as sold under the trade name ACTIVA. Aspects of the invention employ an environmentally benign process to enhance molecular weight of soy protein globulins by linking glutamine and lysine residues with transglutaminase. Transglutaminase covalently links lysine and glutamine residues to one another. This has the effect of enhancing the molecular weight of soy protein globulins. Methods of using transglutaminase enzymes are described, for example, in PCT Pub. No. WO 2021 / 195257, the entirety of the contents of which are incorporated by reference herein. Without being bound by a mechanism of action, it is understood that transglutaminase lacks selectivity for the ends of soy globulins, resulting in covalent linkages randomly selected from the portion of the protein chain that is exposed / reactive. Aspects of the invention generate a high molecular weight branched polymer, with the branched architecture still allowing for enhanced molecular entanglement of the protein solution. Transglutaminase linking may be used in the invention to compensate for the lower amount of protein unfolding and the relatively low molecular weight of soy globulins by significantly enhancing molecular weight. FIG. 1 is a graph of solution viscosity following the addition of transglutaminase. Viscosity is plotted as a function of following addition of transglutaminase addition for a solution of 10% SPI and 1% transglutaminase. The unheated sample gelled after an exponential increase in kinematic viscosity. The viscosity of unheated samples stabilized over time. The unheated mixture viscosity increasing dramatically with time indicates increasing molecular weight, and has a steeper slope when the transglutaminase concentration is higher. The transglutaminase can be degraded with heat. As shown , the 90° bath halts the viscosity increases before the solution gels. Colored recombinant proteins Colored proteins used together with the invention may be naturally occurring proteins, engineered proteins, or proteins derived from naturally occurring proteins. Colored proteins may include chromoproteins (visible light) and fluorescent (UV) proteins. Attorney Docket No.: WERE-002 / 02WO 39529 / 20 Colored proteins may include proteins derived from coral or fluorescent proteins, for example red fluorescent proteins from Discosoma coral. The structure of naturally occurring proteins may be altered to alter the color of the protein. Colored proteins may be recombinantly expressed. Recombinantly expression includes any protein that is expressed from a non-naturally occurring, recombinant DNA construct. The recombinantly expressed protein may be expressed, for example, from a recombinant DNA expression construct in E. coli or S. cerevisiae. The colored protein may be a green fluorescent protein (GFP), a red fluorescent protein (RFP), a near-infrared fluorescent protein, or a blue fluorescent protein (BFP). Near-infrared fluorescent proteins may include fluorescent proteins that are visible as colors other than red, for example, near-infrared fluorescent proteins include small ultra-red fluorescent protein, which actually fluoresces blue. Recombinantly expressed colored proteins may be codon optimized. For example, colored proteins may include the chromoproteins meffRed, eforRed, asPink, spisPink, scOrange, fwYellow, amilGFP, amajLime, cjBlue, meffBlue, aeBlue, amilCP, tsPurple, and gfasPurple, as described in Liljeruhm et al. (2018) J Biol Eng. Experimental Examples First sample dope preparation procedure The following procedure was conducted and yielded approximately 400 mL of dope: STEP 1: Soy protein isolate solution formation 1. Oil bath was set to 70 °C. 2. 20g SPI was added to 200ml diH2O. 3. Solution placed on the oil bath and 7 ml 1M NaOH added on stirrer for 30 mins (pH~10-10.3). 4. 6g SDS added and solution continued to stir for 30 min. The vortex reached the top of the solution when SDS slowly added so that the SDS mixed in fully. A 30 minute timer was started after the SDS was fully mixed in. 5. The solution was removed from the oil bath and left static on the bench (at alkaline conditions) overnight. 6. The next day, the solution was neutralized using 1M HCl (~8ml) and sonicated to create a homogeneous solution. Some protein precipitates may form. The solid was Attorney Docket No.: WERE-002 / 02WO 39529 / 20 broken up in a point probe sonicator. Remaining solid chunks, when present, were removed manually. 7. OPTIONAL: An optional step was included in specific runs. a. Transglutaminase, as sold under the trade name ACTIVA was added to the solution. b. The solution was left at room temperature. c. Then the solution was heated to 90°C after approximately 4 hours. 8. OPTIONAL: In an additional optional step included in specific runs, a colored protein was added with the transglutaminase, after heating the solution, or to the SPI solution that is was not treated with transglutaminase. STEP 2: Alginate solution formation 1. 10g alginic acid sodium salt was added to 200 ml diH2O. 2. The solution was stirred with an overhead mechanical stirrer until well mixed. STEP 3: Dope preparation 1. The SPI and alginate solutions were mixed together in a 1:1 ratio by mass. 2. Bubbles were removed by centrifuge. The centrifuge was run at 2000 x G for 10 minutes and most of the bubbles were removed. STEP 4: Wet spinning process: A wet spinning formulation was demonstrated to be produced through a hand-held syringe and on two different multifilament setups. Different concepts and accomplishments were achieved on each system. Notable fiber mechanisms are summarized in the table below:

[0002] Attorney Docket No.: WERE-002 / 02WO 39529 / 20 Coagulation Post-coagulation bath options Noteworthy results bath that have been demonstrated FIG. 2 is a table of mechanical properties of fibers of the invention. Mechanical properties are detailed for fiber that were extruded from a monofilament hand-held syringe, a fused multifilament, or pulled from a single filament from a multifilament tow. Best mechanical properties are included for each wet spinning configuration. FIG. 3A is a graph of tenacity (cN / tex) and tenacity at yield (cN / tex) of fibers of invention with only a first wash and after a stretching step with a water bath between rollers. FIG.3B is a graph of strain at break yield strain of fibers of invention only a first wash and after a stretching step with a water bath between rollers. Wet drawings (stretching) of fibers enhances mechanical properties. Advantageously, stretching enhances the tenacity of fibers by around a factor of 2. “Dope-dyeing” preparations Sample fibers were “dope-dyed” as monofilaments for three colored proteins, mScarlet-Q (pink chromoprotein), aeBlue (a chromoprotein derived from the anemone Actinia equina), and tsPurple. Fibers were “dope-dyed” on a benchtop multifilament line using engineered colored proteins. FIG.4 shows colored dope-dyed fibers of the invention. Attorney Docket No.: WERE-002 / 02WO 39529 / 20 FIG.5 shows a summary of the impact of using transglutaminase on the resulting color of fibers. Fibers were stress-tested by dipping into various baths of water, buffer, and spin finish. There was no noticeable impact of transglutaminase on color fastness. The fibers had no noticeable color loss overnight in water or after 10 seconds in neutral spin finish (up to 10%) or an anionic surfactant (up to 10%). The fibers experienced substantial color loss in buffers at pH 3, 7.4, 9, and 11 and some color loss in pH 5 buffer. The table below provides a summary of color stability for multifilaments subjected to stress testing by dipping into water, spin finish, and buffers. As described above, since transglutaminase had no noticeable impact on colorfastness, the results for each color apply to the “no TG,” “with TG,” and “after TG” groups. TS Purple MScarlet n “Dope-dyeing” preparations Fibers were colored with “dip-dyed” fibers by dipping a non-colored fiber into a bath of water, transglutaminase, and colored protein overnight. Dip dying was demonstrated with mScarlet-Q, glutamine-tagged mScarlet, and aeBlue. FIG.6 shows dip-dyed fibers of the invention. Dope-dyed fibers present vibrant colors in previously non-colored fibers. Spinning results FIG.7A shows an image of a multi-filament non-colored fiber of the invention. FIG.7B shows an image of multi-filament non-colored fibers of the invention. Attorney Docket No.: WERE-002 / 02WO 39529 / 20 FIG.8 provides a table of the multi-filament fibers of the invention. Row 1 describes the properties of the fiber of FIG.7A and row 2 describes the properties of the fibers of FIG. 7B. As shown, fibers of the invention may be spun using a multi-filament spinner without significant entanglement or loss of favorable properties. Second sample dope preparation procedure Typical dope was made of a mixture ranging from 2:1 to 1:1 ratio of soy protein isolate in water (8-10 wt.%) and medium to high viscosity alginic acid, sodium salt (2.5-5.0 wt.%) Soy protein isolate solution: 1. Deionized (DI) water was poured into a flask 2. The flask was placed in 70 °C 3. Soy protein isolate (SPI) was added to the flask 4. The solution pH was adjusted to 10-11.5 with 1M NaOH and stirred for 30 minutes 5. SDS was added to the flask and stirred for 30 minutes 6. The solution was aged in static condition for at least 12 hours 7. pH was adjusted to ~7.5 with 1M HCl 8. The solution was stirred until the solution became homogeneous 9. Transglutaminase was added to flask and stirred for 40 minutes 10. 3 hours after adding transglutaminase (#8), the solution was stirred for 60 minutes in 60 C Alginate solution 1. Alginate was slowly dissolved in DI water Dope preparation 1. The soy protein isolate and alginate solutions were mixed together in a 1:1 to 1:2 ratio by solution mass alginate solution to soy protein isolate solution. Attorney Docket No.: WERE-002 / 02WO 39529 / 20 Wet spinning process: The formulation produced continuous fibers through a wet spinning process. The process included extrusion through a coagulation medium and subsequent steps of washing, dewatering, and sizing or finishing application. Rollers that carried the fibers through the process induced various draw conditions through variable speeds producing fibers with a range of mechanical properties. FIG.9 is a table of tensile testing results of monofilament fibers. The elongation at break of SA fibers ranged approximately from 3 to 13 (%) and tenacity (strength at break divided by the denier) from 7 to 13 (cN / tex.). Ten fibers were tested per sample and the average value and the standard deviation were calculated. Coagulation bath composition - 0.3-5.0 % CaCl2ranges - pH 4-7 - 20C-25C Fiber properties FIG.10 is an image of monofilament fiber spools of the invention. FIG.11 is an image of multifilament fiber spools of the invention. FIG.12 is an image of multifilament fibers of the invention. Multifilament fibers surface morphology is captured below with optical microscope at 40x. FIG. 13A-B are images of Western Blot and SDS-PAGE showing cross-linking in fibers of the invention. TGase activity with SPI and tagged mScarlet proteins was demonstrated. The difference in banding patterns between SDS-PAGE gel lanes 6 and 13 indicated that SPI crosslinks with itself, forming protein multimers that are too large to migrate into the gel. The difference in banding patterns between SDS-PAGE gel lanes 2 and 8 indicated that mScarlet with the LQSP-tag crosslinks with itself, forming multimers of the protein. Identical banding patterns between lane 8 in both the SDS-PAGE and Western Blot confirm that the observed protein multimers were in fact mScarlet species as they all contain the his tag found on this protein. Lastly, the presence of high molecular weight bands that show up in lane Attorney Docket No.: WERE-002 / 02WO 39529 / 20 14 of both gels (but don't appear in lanes 8-12) indicated some crosslinking between SPI and mScarlet as these bands only appear in the presence of SPI and show up on the Western Blot, Incorporation by Reference References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes. Equivalents Various modifications of the invention and many further embodiments thereof, in addition to those shown and described herein, will become apparent to those skilled in the art from the full contents of this document, including references to the scientific and patent literature cited herein. The subject matter herein contains important information, exemplification and guidance that can be adapted to the practice of this invention in its various embodiments and equivalents thereof.

Claims

Attorney Docket No.: WERE-002 / 02WO 39529 / 20 CLAIMS We claim:

1. A method of preparing fibers, the method comprising: preparing a mixture comprising soy protein isolate (SPI) and water; providing a colored recombinant protein to the mixture; and adding alginate to the mixture.

2. The method of claim 1, further comprising the step of mixing a denaturant into the mixture prior to the step of providing a colored recombinant protein into the mixture.

3. The method of claim 2, wherein the denaturant is sodium dodecyl sulfate (SDS).

4. The method of claim 2, wherein the step of mixing SDS into the mixture is conducted at alkaline conditions.

5. The method of claim 4, wherein the alkaline conditions comprise at least a pH of 10.

6. The method of claim 1, further comprising the step of aging the mixture prior to the step of adding alginate to the mixture.

7. The method of claim 1, wherein the mass ratio of alginate to SPI is between 1:2 and 2:

1.

8. The method of claim 7, wherein the mass ratio is 1:1 or 1:

2.

9. The method of claim 1, wherein the colored recombinant protein comprises less than 1% of the fiber mass.

10. The method of claim 1, wherein in the step of preparing the mixture the SPI is about 10- 25 wt% of the mixture.Attorney Docket No.: WERE-002 / 02WO 39529 / 20 11. The method of claim 2, wherein the ratio of SPI to denaturant in the mixture is about 10:

3.

12. The method of claim 2, wherein the mixing step is completed within 30 minutes.

13. The method of claim 2, wherein the providing step is conducted at least 12 hours after the mixing step is completed.

14. The method of claim 7, further comprising the step of adding hydrochloric acid to the mixture to neutralize the pH of the mixture prior to the step of providing a colored recombinant protein to the mixture.

15. The method of claim 1, further comprising the step of covalently linking glutamine residues to lysine residues in the SPI by adding transglutaminase to the mixture prior to adding alginate to the mixture.

16. The method of claim 15, wherein the step of covalently linking residues comprises adding transglutaminase at room temperate followed by heating the solution to above 50 °C to deactivate the transglutaminase.

17. The method of claim 16, wherein the step of covalently linking residues comprises heating the solution to up to 90°C.

18. The method of claim 1, further comprising the step of wet spinning the mixture using a hand-held syringe, filament tow, or multifilament spinneret.

19. The method of claim 18, wherein the step of wet spinning the mixture comprises wet spinning the mixture into a coagulation bath.

20. The method of claim 18, wherein the coagulation bath comprises an acid and / or CaCl2.Attorney Docket No.: WERE-002 / 02WO 39529 / 20 21. The method of claim 20, wherein the coagulation bath comprises 0.25-10%w / v CaCl2.

22. The method of claim 20, wherein the acid in the coagulation bath comprises 0.25-3% HCl.

23. The method of claim 19, wherein the pH of the coagulation bath is in the pH range 2.8- 5.

8.

24. The method of claim 23, further comprising the step of wet spinning the mixture in a second coagulation bath, wherein the pH of a secondary coagulation bath is the pH range 2.8- 5.

8.

25. The method of claim 24, wherein the pH of the first and / or second coagulation bath is adjusted to a value between 2.8 and 5.8 by a weak or strong acid, or by a buffer such as sodium citrate.

26. The method of claim 1, wherein the method does not comprise the use of urea, thiols, or glutaraldehyde.

27. The method of claim 1, wherein in the step of adding alginate, the alginate is in the form of alginic sodium salt.

28. The method of claim 1, wherein in the step of adding the alginate, the alginate is provided in a mixture with water at 5 wt%.

29. The method of claim 1, wherein the fiber comprises a tenacity greater than 5 cN / tex.

30. The method of claim 1, wherein the fiber comprises an elongation at break % greater than 5%.

31. A high molecular weight fiber comprising:Attorney Docket No.: WERE-002 / 02WO 39529 / 20 soy protein isolate (SPI) comprising glutamine residues covalently linked to lysine residues; alginate; and a colored recombinant protein.

32. The high molecular weight fiber of claim 31, wherein glutamine residues are linked to lysine residues by transglutaminase 33. The high molecular weight fiber of claim 31, wherein glutamine residues are linked to lysine residues by physical entrapment.

34. The high molecular weight fiber of claim 31, wherein the color of the fiber remains unfaded after 24 hours in water.

35. The high molecular weight fiber of claim 31, wherein the color of the fiber remains unfaded after one week in ambient light.

36. A method of preparing fibers, the method comprising: preparing a mixture comprising soy protein isolate (SPI) and water adding alginate to the mixture.

37. The method of claim 36, further comprising the step of mixing a denaturant into the mixture prior to the step of adding alginate to the mixture.

38. The method of claim 37, wherein the denaturant is sodium dodecyl sulfate (SDS).

39. The method of claim 38, wherein the step of mixing SDS into the mixture is conducted at alkaline conditions.

40. The method of claim 39, wherein the alkaline conditions comprise at least a pH of 10.Attorney Docket No.: WERE-002 / 02WO 39529 / 20 41. The method of claim 36, further comprising the step of aging the mixture prior to the step of adding alginate to the mixture.

42. The method of claim 36, wherein the mass ratio of alginate to SPI is between 1:2 and 2:

1.

43. The method of claim 42, wherein the mass ratio is 1:1 or 1:

2.

44. The method of claim 36, wherein in the step of preparing the mixture the SPI is about 10-25 wt% of the mixture.

45. The method of claim 37, wherein the ratio of SPI to denaturant in the mixture is about 10:

3.

46. The method of claim 36, wherein the mixing step is completed within 30 minutes.

47. The method of claim 36, wherein the providing step is conducted at least 12 hours after the mixing step is completed.

48. The method of claim 47, further comprising the step of adding hydrochloric acid to the mixture to neutralize the pH of the mixture prior to the step of adding alginate to the mixture.

49. The method of claim 36, further comprising the step of covalently linking glutamine residues to lysine residues in the SPI by adding transglutaminase to the mixture prior to adding alginate to the mixture.

50. The method of claim 49, wherein the step of covalently linking residues comprises adding transglutaminase at room temperate followed by heating the solution to above 50 °C to deactivate the transglutaminase.Attorney Docket No.: WERE-002 / 02WO 39529 / 20 51. The method of claim 49, wherein the step of covalently linking residues comprises heating the solution to up to 90°C.

52. The method of claim 36, further comprising the step of wet spinning the mixture using a hand-held syringe, filament tow, or multifilament spinneret.

53. The method of claim 52, wherein the step of wet spinning the mixture comprises wet spinning the mixture into a coagulation bath.

54. The method of claim 53, wherein the coagulation bath comprises an acid and / or CaCl2.

55. The method of claim 54, wherein the coagulation bath comprises 0.25-10%w / v CaCl2.

56. The method of claim 54, wherein the acid in the coagulation bath comprises 0.25-3% HCl.

57. The method of claim 53, wherein the pH of the coagulation bath is in the pH range 2.8- 5.

8.

58. The method of claim 57, further comprising the step of wet spinning the mixture in a second coagulation bath, wherein the pH of a secondary coagulation bath is the pH range 2.8- 5.

8.

59. The method of claim 58, wherein the pH of the first and / or second coagulation bath is adjusted to a value between 2.8 and 5.8 by a weak or strong acid, or by a buffer such as sodium citrate.

60. The method of claim 36, wherein the method does not comprise the use of urea, thiols, or glutaraldehyde.Attorney Docket No.: WERE-002 / 02WO 39529 / 20 61. The method of claim 36, wherein in the step of adding alginate, the alginate is in the form of alginic sodium salt.

62. The method of claim 36, wherein in the step of adding the alginate, the alginate is provided in a mixture with water at 5 wt%.

63. The method of claim 36, wherein the fiber comprises a tenacity greater than 5 cN / tex.

64. The method of claim 36, where in the fiber comprises an elongation at break % greater than 5%.

65. A high molecular weight fiber comprising: soy protein isolate (SPI) comprising glutamine residues covalently linked to lysine residues; and alginate.

66. The high molecular weight fiber of claim 65, wherein glutamine residues are linked to lysine residues by transglutaminase 67. The high molecular weight fiber of claim 66, wherein glutamine residues are linked to lysine residues by physical entrapment.

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