Multi-product preparation method based on arabinoxylan-lignin compound

Abstract

The invention relates to the technical field of plant extraction, in particular to a multi-product preparation method based on an arabinoxylan-lignin compound. The method comprises the following steps: treating a lignocellulose raw material by adopting a weak base extracting solution and a strong base extracting solution, and separating an obtained strong base extracting and dealkalizing suspension into an arabinoxylan-lignin compound dispersion liquid and arabinoxylan; performing enzymolysis on the dispersion liquid, and filtering enzymatic hydrolysate to obtain a precipitate which is lignin and a filtrate which is xylooligosaccharide liquid; and separating and purifying the xylooligosaccharide liquid to obtain xylooligosaccharide, xylose and arabinose. According to the method, on the basis of a weak base-strong base two-step extraction process, obtained arabinoxylan-lignin compound dispersion liquid is subjected to enzymolysis, so that lignin, xylooligosaccharide, xylose and arabinose can be continuously prepared, and the reutilization of the arabinoxylan-lignin compound is realized.

Description

Technical Field

[0001] This invention relates to the field of plant extraction technology, and more specifically, to a method for preparing multiple products based on arabinoxylan-lignin complex. Background Technology

[0002] Lignocellulose raw materials are mainly composed of three major components: cellulose, hemicellulose (mainly arabinoxylan), and lignin. These three components are intertwined and connected by chemical bonds such as ester bonds, anisole bonds, and phenyl glycosidic bonds, forming a dense and complex structure that makes separation and degradation difficult. To efficiently utilize lignocellulose resources, existing technologies typically employ alkaline pretreatment to break the bonds between the three components and achieve separation.

[0003] However, in actual production, it was found that even after alkaline pretreatment and precipitation to separate water-insoluble arabinoxylan, a considerable portion of arabinoxylan remained in the system as an arabinoxylan-lignin complex. This complex, due to the stable aggregate mixture formed between lignin and arabinoxylan, gradually forms a colloidal dispersion as the pH of the solution decreases. This increases the viscosity of the system, preventing the precipitate from settling naturally and making it difficult to separate effectively using conventional solid-liquid separation methods (such as centrifugation and filtration). Consequently, the recovery rate of arabinoxylan products is reduced, resulting in significant resource waste.

[0004] Furthermore, due to its complex structure, low component purity, and relatively stable properties, this residual arabinoxylan-lignin complex is difficult to further transform into high-value-added bio-based products and can only be treated as low-value waste. This not only reduces the overall utilization efficiency of lignocellulose resources but also puts pressure on the environment.

[0005] Xylooligosaccharides are degradation products of arabinoxylan, composed of 2-9 xylose units with a degree of polymerization. They are widely used in the food and feed industries and are important functional oligosaccharides. Currently, industrial production mainly involves hydrolyzing raw materials rich in arabinoxylan, such as corn stalks, followed by separation and purification. For example, some methods use weak acids to directly degrade straw raw materials. However, due to the complex structure of the three components of straw, the degradation reaction conditions must be increased. While hemicellulose degrades and dissolves, lignin condenses under acidic conditions, losing a large number of reactive groups, making it difficult to obtain highly reactive alkali lignin, thus limiting its utilization value. Furthermore, the xylooligosaccharide solution after hemicellulose hydrolysis is easily affected by the pore size distribution of the membrane filter material during membrane filtration. The filtration separation efficiency between the main component xylobiose and the hydrolysis byproduct xylose monosaccharides in the xylooligosaccharide product is low, resulting in excessive xylose content in the obtained xylooligosaccharide product. Alternatively, extending the filtration time to reduce xylose content may lead to excessive xylobiose leaching, reducing the product yield.

[0006] Therefore, how to effectively break the complex structure between arabinoxylan and lignin, make full use of alkaline extraction, remove the shielding structure of lignocellulose, and achieve efficient separation and high-value utilization of arabinoxylan has become a technical problem that urgently needs to be solved in the field of lignocellulose resource conversion. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for preparing multiple products based on arabinoxylan-lignin complex.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: This invention provides a method for preparing multiple products based on arabinoxylan-lignin complexes, comprising the following steps: S1. The lignocellulose raw material is extracted, separated, and pH adjusted by sequentially using a weak alkali extract and a strong alkali extract to obtain a strong alkali-extracted dealkali suspension. S2. Separate the strong alkali extraction and dealkali-removing suspension into an arabinoxylan-lignin complex dispersion and arabinoxylan; S3. Using the arabinoxylan-lignin complex dispersion as an enzymatic hydrolysis substrate, xylanase is used for enzymatic hydrolysis to obtain the enzymatic hydrolysis product; S4. Filter the enzymatic hydrolysis product and wash the precipitate. The precipitate after washing is lignin. Combine the filtrate and the washing solution to obtain a xylooligosaccharide solution. S5. The xylooligosaccharide solution is further processed to prepare xylose, arabinose and xylooligosaccharide. In step S4, before enzymatic hydrolysis, the pH of the enzymatic hydrolysis substrate is adjusted to 4.5-5.5; the amount of xylanase added is 2-100 U / g arabinoxylan; the enzymatic hydrolysis temperature is 60℃ and the time is 8-36 h.

[0009] Further, in step S5, the post-processing involves decolorizing and desalting the xylooligosaccharide solution, and then separating xylooligosaccharide, xylose, and arabinose using chromatographic separation, wherein the degree of polymerization of the xylooligosaccharide is 2-9 xylose units.

[0010] Further, in step S2, the strong alkali extraction and dealkali-removing suspension is filtered using a fibrous material to obtain a filter layer; the filter layer is washed with a weak alkali solution and water, and the filtrate and washing liquid are combined to obtain the arabinoxylan-lignin complex dispersion; the solid in the filter layer is separated to obtain the arabinoxylan.

[0011] Furthermore, the fibrous material includes pulp, cotton, and chemical fibers, and the thickness of the filter layer is 1-10 cm; the filtration method using the fibrous material is to apply pressure of 0.2-0.6 mPa to the upper part of the fibrous material and / or to evacuate the lower part of the fibrous material.

[0012] Furthermore, the weak alkaline solution used for cleaning the filter layer is a Na2CO3 or K2CO3 solution, with a mass percentage of Na2CO3 or K2CO3 of 5%-20%.

[0013] Further, the specific process of step S1 is as follows: the lignocellulose raw material is mixed with the weak alkaline extract and heated for extraction to obtain a first solid phase and a first liquid phase; the first solid phase is mixed with the strong alkaline extract and heated for cooking to obtain a second solid phase and a second liquid phase; the second liquid phase is subjected to strong alkali recovery and pH adjustment by adding acid to obtain the strong alkali extract dealkalized suspension.

[0014] Furthermore, the weak alkaline extract is a Na2CO3 solution with a mass percentage of 5-8%, and the strong alkaline extract is a sodium hydroxide solution with a mass percentage of 4%-10%; the heating temperature is 70-100℃, the extraction time is 80-120 min, and the heating and cooking temperature is 80-90℃, the extraction time is 70-90 min.

[0015] Furthermore, the method for recovering the strong alkali is to perform electrodialysis or membrane filtration on the second liquid phase, and the recovery is completed when the mass percentage of the strong alkali in the second liquid phase is 0.5-1.0%.

[0016] Furthermore, the method of adjusting pH by adding acid involves adding HCl, H2SO4 or H3PO4 to the second liquid phase after the strong alkali recovery is completed, and adjusting the pH value to 7-12.

[0017] The beneficial effects of this invention are as follows: (1) The method for preparing multiple products based on arabinoxylan-lignin complex of the present invention, on the basis of the two-step extraction process of weak base-strong base, enzymatically hydrolyzes the obtained arabinoxylan-lignin complex dispersion so that it can be further prepared into lignin, xylooligosaccharide, xylose and arabinose, thereby realizing the reuse of arabinoxylan-lignin complex. (2) The multi-product preparation method based on arabinoxylan-lignin complex of the present invention has mild enzymatic hydrolysis conditions and subsequent separation treatment conditions, which reduces the impact on the chemical properties of each component during the separation process and improves the application of each component in downstream products; (3) The multi-product preparation method based on arabinoxylan-lignin complex of the present invention can take into account the reactivity of lignin during the enzymatic preparation of xylooligosaccharides, prevent lignin from being condensed and degraded, reduce the destruction of active sites, and ensure the application value of lignin. (4) The multi-product preparation method based on arabinoxylan-lignin complex of the present invention uses filamentous fiber material as filter material, which does not require the circulation of the entire solution, but only needs to maintain the pressure of the cleaning liquid, thus saving power and energy and achieving high cleaning efficiency. (5) The multi-product preparation method based on arabinoxylan-lignin complex of the present invention effectively solves the problem that the hydrolysis efficiency is low due to the influence of the complex component structure of the raw material when directly hydrolyzing lignocellulose raw material, and it is impossible to obtain arabinoxylan and high-purity lignin products at the same time. The present invention can obtain multiple products such as lignin, xylooligosaccharide, xylose and arabinose while preparing arabinoxylan, which provides a feasible path for large-scale low-cost separation of lignocellulose and high-value utilization of components. Attached Figure Description

[0018] Figure 1 This is a process flow diagram of the multi-product preparation method based on arabinoxylan-lignin complex of the present invention. Detailed Implementation

[0019] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0020] like Figure 1 As shown, the multi-product preparation method based on arabinoxylan-lignin complex of the present invention includes the following steps: S1. The lignocellulose raw material is extracted, separated, and pH adjusted by sequentially using a weak alkaline extraction solution and a strong alkaline extraction solution to obtain a strong alkaline extraction dealkalized suspension. S2. The strong alkali extraction and dealkali-removing suspension is separated into an arabinoxylan-lignin complex dispersion and arabinoxylan; S3. Using the arabinoxylan-lignin complex dispersion as an enzymatic hydrolysis substrate, xylanase is used for enzymatic hydrolysis to obtain the enzymatic hydrolysis product; S4. Filter the enzymatic hydrolysis product and wash the precipitate. The precipitate after washing is lignin. Combine the filtrate and the washing solution to obtain a xylooligosaccharide solution. S5. The xylooligosaccharide solution is post-processed to prepare xylooligosaccharides, xylose and arabinose.

[0021] The strong-base extraction and dealkalization suspension obtained after weak-base-strong-base extraction still contains a considerable portion of the arabinoxylan-lignin complex after the separation of water-insoluble arabinoxylan. This dispersion is a mixture of multiple components and is difficult to utilize. The method of this invention involves enzymatic hydrolysis of the arabinoxylan-lignin complex dispersion, followed by further separation and processing of the hydrolysis products to ultimately obtain lignin, xylooligosaccharides, xylose, and arabinose, achieving the simultaneous preparation of multiple products.

[0022] Preferably, in step S4, before enzymatic hydrolysis, the pH of the hydrolysis substrate is adjusted to 4.5-5.5; the amount of xylanase added is 2-100 U / g arabinoxylan; the hydrolysis temperature is 60℃; and the time is 8-36 h.

[0023] In the above-described method of the present invention, the enzymatic hydrolysis conditions and subsequent separation treatment conditions are mild, which can effectively separate lignin, xylooligosaccharides, xylose and arabinose, reduce the impact on the chemical properties of each component during the separation process, and improve the application of each component in downstream products. Compared with the prior art, the above-described method of the present invention can take into account the reactivity of lignin during the preparation of xylooligosaccharides, prevent lignin from being condensed and degraded, and prevent a large number of active sites from being destroyed, thus ensuring the application value of lignin.

[0024] Preferably, in step S5, the post-processing involves decolorizing and desalting the xylooligosaccharide solution, and then separating xylooligosaccharide, xylose, and arabinose using chromatographic separation, wherein the degree of polymerization of the xylooligosaccharide is 2-9 xylose units.

[0025] Preferably, decolorization is carried out using activated carbon, and desalination and decolorization are carried out using anion and cation exchange resins. Both of these methods can keep the chemical properties of the product stable during decolorization and desalination, further improving the diversity and application value of the final product.

[0026] After enzymatic hydrolysis of the arabinoxylan-lignin complex, the precipitated lignin was separated by filtration through a filter cloth or centrifugation. The liquid phase was a sugar solution containing xylooligosaccharides, xylose, and arabinose. The mixed sugar solution was purified by desalting and decolorizing with anion and cation exchange resins and activated carbon.

[0027] Preferably, the purified mixed sugar solution is first passed through a cation exchange resin column, then sequentially through an anion exchange resin column and an activated carbon decolorization column at a flow rate of 1-5 times the column volume to desalt and decolorize, thereby purifying the enzymatically hydrolyzed mixed sugar solution.

[0028] Preferably, the desalted and decolorized mixed sugar solution is concentrated to a concentration of 40%-70% to obtain a mixed syrup. The mixed syrup is then separated by a calcium-type chromatographic separation resin column. The chromatographic separation column can be a single column with fractional sample loading or a simulated moving bed with continuous sample loading. The chromatographic separation resin elutes sequentially due to the different adsorption forces of xylooligosaccharides, xylose, and arabinose components in the mixed syrup, and each component is separated by receiving different fractions, ultimately yielding xylooligosaccharide, xylose, and arabinose products.

[0029] Preferably, in step S2, the separation method can be centrifugation or filtration.

[0030] In a further preferred embodiment, the suspension is first washed with a weak alkaline solution or pure water, and then the suspension is washed by centrifugation. The light phase is the arabinoxylan-lignin complex suspension, and the heavy phase is the arabinoxylan.

[0031] By washing the filter layer with water, the insoluble lignin and sodium carbonate salts of sodium carbonate can be washed away, thereby purifying the arabinoxylan intercepted by the filter layer.

[0032] Washing with a weak alkaline solution requires the recovery of the weak alkaline solution and pH adjustment before enzymatic hydrolysis, which is cumbersome and consumes a large amount of acid. In contrast, purifying arabinoxylan by washing with water only requires pH adjustment before enzymatic hydrolysis, making the process simpler and cheaper. Therefore, pure water washing suspension is preferred in this step.

[0033] The filtration method involves using fibrous materials to filter a strong alkali-extracted dealkali suspension, resulting in a filter layer. Then, arabinoxylan is separated from the filter layer after washing with a weak alkali solution. The arabinoxylan gel particles can be intercepted in the tortuous channels formed in the fibrous filter material. The gaps and channels of different sizes formed by the filter material and gel particles during the filtration process, through continuous solvent washing, can fully clean and filter out lignin, effectively reducing the residue of the arabinoxylan-lignin complex and thus improving the product recovery rate.

[0034] Preferably, the thickness of the filter layer is 1-10cm, and the fibrous material includes pulp, cotton, and chemical fiber. The filtration method is to apply pressure of 0.2-0.6mPa to the upper part of the fibrous material.

[0035] The use of filamentous fiber materials and the aforementioned separation conditions offer significant advantages for large-scale industrial production. Because the method of this invention can yield multiple products, large-scale production has greater industrial value in practical applications. The filamentous fiber filter layer used in this invention can be scaled up arbitrarily according to production needs, enabling continuous large-scale operation within the same equipment without the need for expensive high-speed centrifuges. Furthermore, the filamentous fiber filter material itself is inexpensive, can be repeatedly washed and reused, and only requires maintaining a certain level of hydraulic pressure or vacuum to propel the liquid through the curved flow channel; the power consumption is far lower than the enormous energy consumption required for the high-speed rotation of a centrifuge.

[0036] There are many materials that can be used as filter aids, but most of them are granular filter media. If the target product needs to be recovered, granular filter aids are difficult to separate. This invention selects filamentous fiber filter media, which cleverly solves the problems of difficult sedimentation of arabinoxylan suspension and easy clogging of filter layer by gel. Filamentous fiber filter layer has the advantages of high sample carrying capacity, high separation efficiency, low filtration power consumption, and easy separation, recycling and reuse of filter media.

[0037] Preferably, step S1 is a two-step extraction process of weak base and strong base. The specific process is as follows: the raw material is mixed with the weak base extract and heated for extraction to obtain a first solid phase and a first liquid phase. The first solid phase is mixed with the strong base extract and heated for cooking to obtain a second solid phase and a second liquid phase. The second liquid phase is subjected to strong base recovery and pH adjustment by adding acid to obtain a strong base extract dealkalized suspension.

[0038] First, a weak alkaline extract was used for extraction, followed by a strong alkaline extract. By fully utilizing the differences in the degradation properties of the weak and strong alkaline extracts on the three chemical bonds connecting the raw material lignocellulose and their solubility properties on lignin and arabinoxylan, a two-step preparation of alkali lignin and arabinoxylan was achieved.

[0039] Traditional strong alkali processes dissolve lignin and hemicellulose simultaneously. Although the bonds are broken, arabinoxylan and lignin still form indivisible complex aggregates. In addition, strong alkali itself tends to further degrade both into scattered small molecules, resulting in a decrease in the yield of lignin and arabinoxylan and difficulty in improving purity.

[0040] The above steps of the present invention first selectively extract soluble lignin with a mild weak alkali. The system is mild and has minimal degradation. Furthermore, the weak alkali extraction can yield lignin with high purity. At the same time, after treatment with a weak alkali, extraction with a strong alkali can improve the efficiency of separating arabinoxylan.

[0041] Preferably, the weak alkaline extract is a Na2CO3 solution with a mass percentage of 5-8%, and the strong alkaline extract is a sodium hydroxide solution with a mass percentage of 4%-8%; the heating temperature is 70-100℃, the extraction time is 80-120 min, and the heating and cooking temperature is 80-90℃, the extraction time is 70-90 min.

[0042] Preferably, the raw materials and the weak alkaline extract are mixed in a solid-liquid mass-volume ratio of 1:5-12, and the first solid phase is mixed with the strong alkaline extract in a solid-liquid mass-volume ratio of 1:5-12.

[0043] Preferably, for the first liquid phase, alkali lignin can be obtained by adjusting the pH value with acid, and the second solid phase is the cellulose product, which can be used for pulping or further saccharification, and then fermented by microorganisms to produce fuel ethanol, etc.

[0044] Preferably, the method for recovering strong alkali is to perform electrodialysis or membrane filtration on the second liquid phase, and the recovery is completed when the mass percentage of strong alkali in the second liquid phase is 0.5-1.0%.

[0045] Preferably, the method for adjusting the pH by adding acid is to add HCl, H2SO4 or H3PO4 to the second liquid phase after the strong alkali recovery is completed, and adjust the pH value to 7-12.

[0046] Preferably, the specific process of step S1 of the present invention is as follows: S1-1. First, the raw material is crushed into filamentous fibers or fine particles. After washing with water, impurities such as salts, microorganisms, and their metabolites are removed from the raw material, followed by screw extrusion. The raw material treated as above is mixed with a 6% Na2CO3 solution at a solid-liquid mass-to-volume ratio of 1:8, heated to 90℃, and extracted for 80 minutes. Then, solid-liquid separation is performed to obtain the first liquid phase and the first solid phase.

[0047] The lignocellulose raw materials used are specifically one or more of the following: sugarcane bagasse, sugarcane leaves, corn stalks, corn cobs, bamboo, reeds, wheat straw, and rice straw.

[0048] S1-2. Na2CO3 in the first liquid phase is recovered by electrodialysis or nanofiltration / ultrafiltration membrane filtration; the pH value of the first liquid phase is adjusted by adding acid to obtain a precipitate, the precipitate is separated and dried to obtain alkali lignin.

[0049] Preferably, the method for adjusting the pH value by adding acid in this step is to add HCl to the first liquid phase and adjust the pH value to 2-4.

[0050] S1-3. Add 8% NaOH solution by mass to the first solid phase, with a solid-liquid mass-volume ratio of 1:6. Extract by boiling at 80℃ for 70 min. After extraction, perform solid-liquid separation to obtain the second solid phase and the second liquid phase.

[0051] S1-4. The second liquid phase obtained in step S1-3 is subjected to strong alkali recovery and pH adjustment by adding acid to obtain a strong alkali extraction and dealkali-removing suspension.

[0052] The present invention will be illustrated by specific embodiments below.

[0053] Example 1 The specific steps for preparing arabinoxylan using the method of the present invention are as follows: Take 120 kg of absolutely dry corn cob raw material, first crush the raw material into small particles and place it in an extraction container, add 6 times the mass of 0.5% NaOH solution and stir to mix well, use extrusion dehydration, and wash to remove impurities such as salts, microorganisms and their metabolites from the raw material.

[0054] Seven times the mass of a weak alkaline extract was added to the cleaned raw material, stirred evenly, and then heated for extraction. In this embodiment, the weak alkaline extract was a 5% (w / w) Na₂CO₃ solution, the temperature was 100°C, and the holding time was 80 min. After extraction, the material was processed using a screw press to separate the solid and liquid phases, obtaining a first solid phase and a first liquid phase.

[0055] The first solid phase was washed with water and then subjected to solid-liquid separation again, with the liquid phase being combined with the first liquid phase. Na2CO3 in the first liquid phase was recovered using an alkali-resistant membrane device. The first liquid phase solution, from which Na2CO3 was removed, was precipitated with acid, and the precipitate was separated and dried to obtain alkali lignin.

[0056] A total of 6 times its mass of NaOH solution was added to the first solid phase and stirred until homogeneous. The mixture was then subjected to heating and boiling extraction. In this embodiment, the final concentration of the NaOH solution was 8%, the heating temperature was 90°C, and the holding time was 70 min. After extraction, the mixture was centrifuged to separate the solid and liquid phases, yielding a second solid phase and a second liquid phase.

[0057] The second solid phase is washed with water and then subjected to solid-liquid separation again. The washed second solid phase is cellulose. The liquid phase obtained from washing is combined with the second liquid phase, and NaOH in the second liquid phase is recovered using an alkali-resistant membrane device. The second liquid phase, from which NaOH has been removed, is then treated with hydrochloric acid to adjust the pH to 9. As the pH value decreases, a precipitate forms, creating a precipitate suspension, which is the strong alkali extraction and dealkali removal suspension.

[0058] It was separated into an arabinoxylan-lignin complex dispersion and arabinoxylan.

[0059] In this embodiment, the strong alkali extraction and dealkali-removed suspension is filtered using pulp material to obtain a filter layer. Arabicaxylan is then separated from the filter layer after washing with a weak alkali solution. The filter layer is 8 cm thick and pressurized at 0.4 MPa. The filter layer is repeatedly washed with Na₂CO₃ solution to dissolve lignin until the effluent is light-colored or colorless. The combined effluents are then used to obtain the arabinoxylan-lignin complex dispersion. The filter layer is then dispersed with pure water, and the solid phase is separated using a twin-screw dehydrator. After concentration and drying, the arabinoxylan product is obtained.

[0060] The pH of the arabinoxylan-lignin solution was adjusted to 5.0, and the enzyme dosage was 20 U / g arabinoxylan. Enzymatic hydrolysis was carried out at 60℃ for 16 h. The hydrolysate was filtered, and the precipitate was washed with water. The precipitate was lignin. The washing liquid phases were combined to obtain a xylooligosaccharide solution. The xylooligosaccharide solution was decolorized by activated carbon and desalted by anion and cation exchange resins.

[0061] The decolorized and desalted xylooligosaccharide solution was concentrated under vacuum, or xylooligosaccharides, xylose, and arabinose were separated directly by chromatographic methods. The yield of xylooligosaccharides was 56.15%, the yield of xylose was 0.48%, and the yield of arabinose was 0.22%.

[0062] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing multiple products based on arabinoxylan-lignin complexes, characterized in that, Includes the following steps: S1. The lignocellulose raw material is extracted, separated, and pH adjusted by sequentially using a weak alkaline extract and a strong alkaline extract to obtain a strong alkaline extract dealkalized suspension. S2. Separate the strong alkali extraction and dealkali-removing suspension into an arabinoxylan-lignin complex dispersion and arabinoxylan; S3. Using the arabinoxylan-lignin complex dispersion as an enzymatic hydrolysis substrate, xylanase is used for enzymatic hydrolysis to obtain the enzymatic hydrolysis product; S4. Filter the enzymatic hydrolysis product and wash the precipitate. The precipitate after washing is lignin. Combine the filtrate and the washing solution to obtain a xylooligosaccharide solution. S5. The xylooligosaccharide solution is post-processed to prepare xylooligosaccharide, xylose and arabinose.

2. The method for preparing multiple products based on arabinoxylan-lignin complex according to claim 1, characterized in that, In step S4, before enzymatic hydrolysis, the pH of the hydrolysis substrate is adjusted to 4.5-5.5; the amount of xylanase added is 2-100 U / g arabinoxylan; the hydrolysis temperature is 60℃; and the time is 8-36 h.

3. The method for preparing multiple products based on arabinoxylan-lignin complex according to claim 1, characterized in that, In step S5, the post-processing involves decolorizing and desalting the xylooligosaccharide solution, and then separating xylooligosaccharide, xylose, and arabinose using chromatographic separation. The degree of polymerization of the xylooligosaccharide is 2-9 xylose units.

4. The method for preparing multiple products based on arabinoxylan-lignin complex according to claim 1, characterized in that, In step S2, the strong alkali extraction and dealkali-removing suspension is filtered using a fibrous material to obtain a filter layer; the filter layer is washed with a weak alkali solution or pure water, and the filtrate and washing liquid are combined to obtain the arabinoxylan-lignin complex dispersion; the solid in the filter layer is separated to obtain the arabinoxylan.

5. The method for preparing multiple products based on arabinoxylan-lignin complex according to claim 4, characterized in that, The filamentous material includes pulp, cotton, and chemical fibers, and the thickness of the filter layer is 1-10 cm. The filtration method using the filamentous material is to apply pressure of 0.2-0.6 mPa to the upper part of the filamentous material and / or to evacuate the lower part of the filamentous material.

6. The method for preparing multiple products based on arabinoxylan-lignin complex according to claim 4, characterized in that, The filter cleaning weak alkaline solution is a Na2CO3 or K2CO3 solution, with the mass percentage of Na2CO3 being 5%-20%.

7. A method for preparing multiple products based on arabinoxylan-lignin complex according to any one of claims 1-6, characterized in that, The specific process of step S1 is as follows: the lignocellulose raw material is mixed with the weak alkaline extract and heated for extraction to obtain a first solid phase and a first liquid phase; the first solid phase is mixed with the strong alkaline extract and heated for cooking to obtain a second solid phase and a second liquid phase; the second liquid phase is subjected to strong alkali recovery and pH adjustment by adding acid to obtain the strong alkali extract dealkali suspension.

8. The method for preparing multiple products based on arabinoxylan-lignin complex according to claim 7, characterized in that, The raw material extraction weak alkaline extract is a Na2CO3 solution with a mass percentage of 5-8%, and the strong alkaline extract is a sodium hydroxide solution with a mass percentage of 4%-12%. The heating temperature is 70-100℃, and the extraction time is 80-120 min. The heating and cooking temperature is 80-90℃, and the extraction time is 70-90 min.

9. A method for preparing multiple products based on arabinoxylan-lignin complex according to claim 7, characterized in that, The method for recovering the strong alkali is to perform electrodialysis or membrane filtration on the second liquid phase, and the recovery is completed when the mass percentage of the strong alkali in the second liquid phase is 0.5-1.0%.

10. A method for preparing multiple products based on arabinoxylan-lignin complex according to claim 9, characterized in that, The method for adjusting pH by adding acid is to add HCl, H2SO4 or H3PO4 to the second liquid phase after the strong alkali recovery is completed, and adjust the pH value to 7-12.

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