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US-12624126-B2 - Dextran-alpha-glucan graft copolymers and derivatives thereof

US12624126B2US 12624126 B2US12624126 B2US 12624126B2US-12624126-B2

Abstract

Disclosed herein are compositions comprising at least one alpha-glucan graft copolymer derivative compound (e.g., ether or ester) having a degree of substitution (DoS) up to about 3.0. The precursors of these derivative compounds are graft copolymers that comprise a dextran backbone and alpha-glucan side chains. At least about 30% of the glycosidic linkages of the alpha-glucan side chains are alpha-1,3 glycosidic linkages. Further disclosed are methods of producing graft copolymer derivatives, as well as their use in various applications and products.

Inventors

  • Douglas J. Adelman
  • Natnael Behabtu
  • Christian Peter Lenges
  • Kyle Kim
  • Geert Van Der Kraan
  • Rong Guan

Assignees

  • Nutrition & Biosciences USA 4, Inc.

Dates

Publication Date
20260512
Application Date
20210603

Claims (20)

  1. 1 . A composition comprising at least one graft copolymer ether compound having a degree of substitution (DoS) up to about 3.0, wherein the graft copolymer comprises: (i) a backbone comprising dextran, and (ii) one or more alpha-glucan side chains comprising at least about 30% alpha-1,3 glycosidic linkages; wherein the graft copolymer ether compound is (i) an anionic graft copolymer ether compound, or (ii) a cationic graft copolymer ether compound, and wherein the graft copolymer ether compound is crosslinked.
  2. 2 . The composition of claim 1 , wherein the graft copolymer comprises about 20 wt % to about 80 wt % of said backbone, and about 20 wt % to about 80 wt % of said one or more alpha-glucan side chains.
  3. 3 . The composition of claim 1 , wherein the one or more alpha-glucan side chains comprise at least about 90% alpha-1,3 glycosidic linkages.
  4. 4 . The composition of claim 3 , wherein the weight-average degree of polymerization (DPw) of the one or more alpha-glucan side chains is at least about 15.
  5. 5 . The composition of claim 3 , wherein the one or more alpha-glucan side chains comprise about 100% alpha-1,3 glycosidic linkages.
  6. 6 . The composition of claim 1 , wherein the weight-average degree of polymerization (DPw) of the one or more alpha-glucan side chains is at least about 15.
  7. 7 . The composition of claim 1 , wherein the dextran comprises at least about 90% alpha-1,6 glycosidic linkages.
  8. 8 . The composition of claim 1 , wherein the weight-average molecular weight (Mw) of the dextran is at least about 5000 Daltons.
  9. 9 . The composition of claim 1 , wherein the graft copolymer ether compound is water-soluble.
  10. 10 . The composition of claim 1 , wherein the DoS of the graft copolymer ether compound is about 0.05 to about 0.9.
  11. 11 . The composition of claim 1 , wherein the DoS of the graft copolymer ether compound is 0.3 to 1.25.
  12. 12 . The composition of claim 1 , wherein the graft copolymer ether compound is the anionic graft copolymer ether compound.
  13. 13 . The composition of claim 12 , wherein the anionic graft copolymer ether compound comprises carboxymethyl groups.
  14. 14 . The composition of claim 1 , wherein the graft copolymer ether compound is the cationic graft copolymer ether compound.
  15. 15 . The composition of claim 14 , wherein the cationic graft copolymer ether compound comprises quaternary ammonium groups.
  16. 16 . The composition of claim 1 , wherein the composition is a: (a) flocculation agent, (b) absorbent, (c) viscosity modifier, (d) paper, (e) emulsion, or (f) builder agent.
  17. 17 . The composition of claim 1 , wherein the graft copolymer ether compound is crosslinked using a diglycidyl ether.
  18. 18 . The composition of claim 17 , wherein the diglycidyl ether is ethylene glycol diglycidyl ether.
  19. 19 . A flocculation method comprising: (a) mixing a graft copolymer ether compound according to claim 1 into an aqueous composition that comprises suspended solids, whereby at least a portion of the suspended solids becomes flocculated; and (b) optionally, separating the flocculated solids of (a) from the aqueous composition.
  20. 20 . An absorption method comprising: contacting a graft copolymer ether compound according to claim 1 with an aqueous liquid-comprising composition, wherein the compound absorbs aqueous liquid from the liquid-comprising composition.

Description

This application is the National Stage application of International Application No. PCT/US2021/035623 (filed Jun. 3, 2021), which claims the benefit of U.S. Provisional Appl. No. 63/034,437 (filed Jun. 4, 2020), both of which prior applications are incorporated herein by reference in their entirety. FIELD The present disclosure is in the field of polysaccharides and polysaccharide derivatives. For example, the disclosure pertains to derivatives of dextran-alpha-glucan graft copolymers, methods of their production, and use of this material in various applications. BACKGROUND Driven by a desire to use polysaccharides in various applications, researchers have explored for polysaccharides that are biodegradable and that can be made economically from renewably sourced feedstocks. One such polysaccharide is alpha-1,3-glucan, an insoluble glucan polymer characterized by having alpha-1,3 glycosidic linkages. This polymer has been prepared, for example, using a glucosyltransferase enzyme isolated from Streptococcus salivarius (Simpson et al., Microbiology 141:1451-1460, 1995). Also for example, U.S. Pat. No. 7,000,000 disclosed the preparation of a spun fiber from enzymatically produced alpha-1,3-glucan. Various other glucan materials have also been studied for developing new or enhanced applications. For example, U.S. Patent Appl. Publ. No. 2015/0232819 discloses enzymatic synthesis of several insoluble glucans having mixed alpha-1,3 and -1,6 linkages. Despite this work, new forms of alpha-1,3-glucan are desired to enhance the economic value and performance characteristics of this material in various applications. Compositions comprising alpha-1,3-glucan in the form of a derivatized graft copolymer are presently disclosed to address this need. SUMMARY In one embodiment, the present disclosure concerns a composition comprising at least one graft copolymer ether or ester compound having a degree of substitution (DoS) up to about 3.0, wherein the graft copolymer comprises: (i) a backbone comprising dextran, and (ii) alpha-glucan side chains comprising at least about 30% alpha-1,3 glycosidic linkages. In another embodiment, the present disclosure concerns a method of producing a graft copolymer ether or ester compound herein, the method comprising: (a) contacting a graft copolymer in a reaction with at least one etherification agent or esterification agent comprising an organic group, wherein at least one organic group is etherified or esterified to the graft copolymer thereby producing a graft copolymer ether or ester compound, wherein the graft copolymer ether or ester compound has a degree of substitution (DoS) up to about 3.0, wherein the graft copolymer comprises: (i) a backbone comprising dextran, and (ii) alpha-glucan side chains comprising at least about 30% alpha-1,3 glycosidic linkages; and (b) optionally, isolating the graft copolymer ether or ester compound produced in step (a). In another embodiment, the present disclosure concerns a flocculation method comprising: (a) mixing a graft copolymer ether or ester compound herein into an aqueous composition that comprises suspended solids, whereby at least a portion of the suspended solids becomes flocculated; and (b) optionally, separating the flocculated solids of (a) from the aqueous composition. In another embodiment, the present disclosure concerns an absorption method comprising: contacting a graft copolymer ether or ester compound herein with an aqueous liquid-comprising composition, wherein the compound absorbs aqueous liquid from the liquid-comprising composition. DETAILED DESCRIPTION The disclosures of all cited patent and non-patent literature are incorporated herein by reference in their entirety. Unless otherwise disclosed, the terms “a”, “an” and “the” as used herein are intended to encompass one or more (i.e., at least one) of a referenced feature. Where present, all ranges are inclusive and combinable, except as otherwise noted. For example, when a range of “1 to 5” (i.e., 1-5) is recited, the recited range should be construed as including ranges “1 to 4”, “1 to 3”, “1-2”, “1-2 & 4-5”, “1-3 & 5”, and the like. The term “copolymer” herein refers to a polymer comprising at least two different types of alpha-glucan, such as dextran and alpha-1,3-glucan. The terms “graft copolymer”, “branched copolymer” and the like herein generally refer to a copolymer comprising a “backbone” (or “main chain”) and side chains branching from the backbone. The side chains are structurally distinct from the backbone. Examples of graft copolymers herein are “dextran-alpha-1,3-glucan graft copolymers” (and like terms) that comprise a backbone comprising dextran, and side chains of alpha-1,3-glucan. A backbone in some aspects can itself be a branched dextran as disclosed herein; the addition of alpha-1,3-glucan side chains to such a backbone (thereby forming a graft copolymer herein) can be, for example, via enzymatic extension from non-reducing ends presented by short br