Search

CN-121975886-A - Low-branched beta- (1, 3) -D-galactan with high main chain bond content and collaborative enzymatic preparation method thereof

CN121975886ACN 121975886 ACN121975886 ACN 121975886ACN-121975886-A

Abstract

The invention provides low-branched-chain beta- (1, 3) -D-galactan with high main chain bond content and a collaborative enzymatic method thereof, belonging to the technical field of preparation of polysaccharide with a specific structure. According to the method, larch arabinogalactan is used as a substrate, a composite enzyme system consisting of beta- (1, 6) -D-galactanase and alpha-1, 3-arabinosidase derived from penicillium oxalicum is utilized to carry out synergistic and directional enzymolysis, and beta- (1, 6) -D-galactose side chains and connected arabinose are effectively removed, so that beta-1, 3-galactan with complete main chain and obviously reduced branched chains is obtained. The low-branched-chain beta- (1, 3) -D-galactan prepared by the invention can be used in the fields of immunomodulators, functional food additives and the like, and has the effects of obviously enhancing the immunocompetence, improving the intestinal health and the like.

Inventors

  • TANG SHUO
  • HUANG XIAODE
  • CHEN BIN
  • WANG LEI

Assignees

  • 中华全国供销合作总社南京野生植物综合利用研究所

Dates

Publication Date
20260505
Application Date
20251222

Claims (10)

  1. 1. The preparation method of the low-branched-chain beta-1, 3-galactan is characterized by comprising the following steps: S1, dissolving larch arabinogalactan in a buffer solution with the pH of 5.5-6.5 to prepare a polysaccharide solution with the concentration of 1-4% w/v, and then adding a complex enzyme for enzymolysis reaction, wherein the complex enzyme comprises beta- (1, 6) -D-galactanase and alpha-1, 3-arabinosidase; S2, heating the solution after the enzymolysis reaction to inactivate enzymes; S3, purifying the solution after enzyme deactivation to obtain a low-branched-chain beta-1, 3-galactan product.
  2. 2. The method according to claim 1, wherein in step S1, the volume ratio of β - (1, 6) -D-galactosidase to α -1, 3-arabinosidase is 2-5:1.
  3. 3. The method according to claim 1, wherein in the step S1, the complex enzyme is added in an amount of 5 to 15. Mu.L per 10mL parts of the polysaccharide solution.
  4. 4. The method according to claim 1, wherein in step S1, the temperature of the enzymatic hydrolysis reaction is 45-55 ℃ and the reaction time is 4-12 hours.
  5. 5. The method according to claim 1, wherein in step S2, the heating treatment is performed at a temperature of 90 to 100 ℃ for a treatment time of 15 to 25 minutes.
  6. 6. The method according to claim 1, wherein in step S3, the purification treatment comprises ultrafiltration using an ultrafiltration membrane having a molecular weight cut-off of 500 to 2000 Da, collecting the concentrated solution which is cut-off and drying.
  7. 7. A low branched beta-1, 3-galactan prepared by the process of any one of claims 1-6.
  8. 8. The low branched beta-1, 3-galactan according to claim 7, wherein the galactose residues are not less than 50% by mole based on → 3) -Galp- (1→ linkage.
  9. 9. Use of a low branched beta-1, 3-galactan according to claim 7 or 8 in the manufacture of a product for modulating or enhancing immune activity.
  10. 10. The use according to claim 9, wherein said modulating or enhancing immune activity comprises promoting nitric oxide and/or interleukin-6 release by macrophages.

Description

Low-branched beta- (1, 3) -D-galactan with high main chain bond content and collaborative enzymatic preparation method thereof Technical Field The invention relates to the technical field of preparation of polysaccharides with specific structures, in particular to low-branched-chain beta- (1, 3) -D-galactan with high main chain bond content and a collaborative enzymatic method thereof. Background Larch arabinogalactan (Arabinogalactan, AG) is a neutral polysaccharide widely existing in conifer xylem, especially larch (Larix olgensis) with the most abundant content of 25% -30%. The polysaccharide has a highly branched structure, wherein the main chain of the polysaccharide is formed by connecting beta- (1, 3) -D-galactose through beta-1, 3 glycosidic bonds, and the side chain of the polysaccharide mainly comprises beta- (1, 6) -D-galactose and a small amount of L-arabinose, so that a complex branch network is formed. Studies have shown that the higher structure of polysaccharides has a decisive influence on their biological activity, in particular that polysaccharides with beta- (1, 3) -D-galactose as main chain are capable of forming stable triple helix structures in aqueous solution, and this feature is considered as a key basis for the immunological activity of polysaccharides. The study by Chen et al has demonstrated that polysaccharide FVPH having a complete triple helix structure exhibits significantly enhanced immunomodulatory activity compared to polysaccharide FVPU with a disrupted triple helix structure. Arabinogalactan has the same type of glycosidic linkage as compared to β - (1, 3) -D-glucan, but differs in structure in that arabinogalactan has a richer β - (1, 6) -D-galactose side chain and a small amount of arabinose side chain. However, larch arabinogalactan does not possess a stable triple helix structure, mainly due to its abundant side chain structure, which blocks the formation and stabilization of hydrogen bonds between the main chains, thereby affecting the integrity of the triple helix structure. This phenomenon is particularly evident in arabinogalactans, where the highly branched side chain structure severely interferes with the ordered arrangement of the main chain, resulting in the inability to form a triple helix structure with biological activity. Therefore, by effectively regulating and controlling the abundance of the branched chains, reconstructing the higher structure of the arabinogalactan is a key for improving the immunocompetence of the arabinogalactan. The directed degradation of arabinogalactan side chains requires the involvement of specific enzyme systems, including arabinosidase and beta- (1, 6) -D-galactosidase. Through scientific compounding of the enzymes, the accurate degradation of the arabinogalactan branched chains can be realized, so that the low branched chain beta- (1, 3) -D-galactan with a definite structure is obtained. In the prior art, a specific degradation method aiming at the branched chains of the arabinogalactan does not exist, and the beta- (1, 3) -D-galactan with controllable branched chain content cannot be obtained. This not only limits the intensive research on the relationship of arabinogalactan structure to activity, but also hampers the application and development of arabinogalactan as a functional food additive and drug delivery vehicle. The patent aims at providing an innovative method for directionally degrading arabinogalactan branched chains through complex enzyme to obtain low-branched-chain beta- (1, 3) -D-galactan, solves the problem of lacking a structure-controllable beta- (1, 3) -D-galactan preparation technology in the prior art, and lays a foundation for developing arabinogalactan derivatives with higher biological activity. Disclosure of Invention The prior art lacks a specific degradation method aiming at the arabinogalactan branched chains, and the low branched chain beta- (1, 3) -D-galactan with a definite structure cannot be obtained, so that the application of the arabinogalactan branched chains in the fields of functional foods, medicines and cosmetics is restricted. The invention aims to overcome the defects of the prior art and provide an enzymatic method for preparing low-branched-chain beta-1, 3-galactan with mild conditions, strong specificity and controllable product structure. It is another object of the present invention to provide a low branched beta-1, 3-galactan having a specific molecular weight produced by the above method. In order to achieve the above purpose, the invention adopts the following technical scheme: in a first aspect, the invention provides a method for preparing low branched beta-1, 3-galactan, comprising the steps of: S1, dissolving larch arabinogalactan in a buffer solution with the pH of 5.5-6.5 to prepare a polysaccharide solution with the concentration of 1-4% (w/v), and then adding a complex enzyme for enzymolysis reaction, wherein the complex enzyme comprises beta- (1, 6) -D-galactanas