Extraction process for efficiently extracting cellulose from aquilaria sinensis

Abstract

The invention discloses an extraction process for efficiently extracting cellulose from aquilaria sinensis, and relates to the technical field of textile fibers. The extraction process for efficiently extracting cellulose from aquilaria sinensis at least comprises the following steps: cleaning aquilaria sinensis, removing impurities, drying and crushing to obtain aquilaria sinensis powder; adding the aquilaria sinensis powder into petroleum ether, and performing reflux treatment to obtain dewaxed aquilaria sinensis powder; adding the dewaxed aquilaria sinensis powder into a compound enzyme solution, performing ultrasonic treatment, filtering, washing and drying to obtain enzymolysis aquilaria sinensis powder; adding the enzymolysis aquilaria sinensis powder into a sodium hydroxide solution, extracting at low temperature, heating, stirring, extracting and filtering to obtain alkali extraction cellulose filter residues; and dispersing the alkali extraction cellulose filter residue in a bleaching solution, stirring, adding disodium ethylene diamine tetraacetate, stirring, filtering, washing and drying to obtain the aquilaria sinensis cellulose. The aquilaria sinensis fiber prepared by the extraction process provided by the invention is high in cellulose content, moderate in polymerization degree and good in reaction activity.

Description

Technical Field

[0001] This invention relates to the field of textile fiber technology, specifically to an efficient extraction process for cellulose from *Agrostis stenoptera*. Background Technology

[0002] Cellulose is the most abundant renewable and biodegradable polysaccharide in nature. Its molecular structure possesses excellent mechanical properties and functionalization potential, and it is widely used in various industrial fields such as textiles, papermaking, food, medicine, and bio-based materials. It is one of the core raw materials for preparing green and environmentally friendly products to replace fossil resources, and its resource utilization has attracted widespread attention. Lignocellulosic biomass, as the main source of cellulose, is mainly composed of cellulose, hemicellulose, and lignin. These three components form a complex and dense structure similar to "reinforced concrete." Cellulose is encapsulated by hemicellulose, lignin, and impurities such as lipids and waxes, making the efficient separation and purification of cellulose a core technical challenge in the industry. As a widely distributed grass in South my country (especially Dongguan and surrounding areas), *Agrostis stenoptera* is abundant and readily available. Its fiber has a high cellulose content and has been shown to possess natural antibacterial properties, making it a highly promising lignocellulose raw material. Its application in the textile new materials field is being explored, contributing to the upgrading of local specialty industries. However, the current utilization rate of *Agrostis stenoptera* resources is low. Most of it is not utilized for high-value purposes after harvesting, being used only for simple weaving, composting, or direct disposal. This not only wastes renewable resources but also potentially imposes an environmental burden. Therefore, realizing the high-value transformation of *Agrostis stenoptera*, especially the extraction of high-purity cellulose, has significant economic and ecological value.

[0003] Currently, traditional processes for extracting cellulose from herbaceous plants mainly include acid hydrolysis, alkaline hydrolysis, and single enzymatic hydrolysis. However, these processes generally have many defects and are difficult to meet the needs of industrial production and high-quality cellulose preparation. While acid hydrolysis is simple to operate and has a relatively fast extraction rate, it requires strong acids as catalysts. This not only leads to the breakage of cellulose molecular chains and a decrease in the degree of polymerization, affecting product quality, but also generates a large amount of highly polluting wastewater, causing serious environmental damage. Furthermore, it causes severe equipment corrosion, increasing production energy consumption and costs. Alkaline hydrolysis often uses high-temperature, strong alkali to directly treat the raw materials. Although it can dissolve hemicellulose and lignin to some extent, it easily causes cellulose yellowing and degradation, resulting in low product whiteness and purity. Additionally, it requires large amounts of alkali, making subsequent wastewater treatment difficult and costly. While single enzymatic hydrolysis has the advantages of being environmentally friendly and causing less damage to cellulose, it can only degrade a single type of non-cellulose impurity. Enzymatic hydrolysis efficiency is low, processing time is long, and enzyme preparation costs are high, making large-scale application difficult. Furthermore, some processes use single physical or chemical treatment methods without synergistic effects, resulting in low cellulose extraction rates and high impurity residues, making it difficult to meet the high-purity cellulose requirements of viscose spinning, high-end papermaking, and other fields. Therefore, developing an efficient, environmentally friendly cellulose extraction process from *Hedysarum heterotropoides* that can improve the overall performance of cellulose is of significant practical importance. Summary of the Invention

[0004] The purpose of this invention is to provide an efficient extraction process for cellulose from *Aquilaria sinensis*, thereby solving the following technical problems: Existing cellulose extraction processes from plants suffer from low extraction rates, low cellulose content, and environmentally unfriendly processes.

[0005] The objective of this invention can be achieved through the following technical solutions: An efficient extraction process for cellulose from *Agrostis chinensis* includes at least the following steps: After washing, removing impurities, drying, and pulverizing, the grass is obtained as grass powder. The powdered agarwood was added to petroleum ether and refluxed to obtain dewaxed agarwood powder. The dewaxed *Alopecurus aequalis* powder was added to a compound enzyme solution, ultrasonically treated, filtered, washed and dried to obtain enzymatically hydrolyzed *Alopecurus aequalis* powder. The enzymatically hydrolyzed *Dendrobium nobile* powder was added to a sodium hydroxide solution, extracted at low temperature, then heated and stirred for further extraction and filtration to obtain alkali-extracted cellulose residue. The alkali-extracted cellulose residue was dispersed in a bleaching solution, stirred, and then disodium ethylenediaminetetraacetate was added. The mixture was stirred, filtered, washed, and dried to obtain sedge cellulose.

[0006] As a further aspect of the present invention: the particle size of the *Achyranthes bidentata* powder is 40-60 mesh, the ratio of the *Achyranthes bidentata* powder to the petroleum ether is 1g:8-12mL, and the reflux treatment temperature is 80-90℃ and the time is 6-9h.

[0007] As a further aspect of the present invention: the composite enzyme solution is a mixed solution of pectinase and xylanase, wherein the concentration of pectinase is 1.5-2.5 wt%, the concentration of xylanase is 0.5-1.5 wt%, and the pH value of the composite enzyme solution is 4-6.

[0008] As a further aspect of the present invention: the ratio of the dewaxed angelica powder to the compound enzyme solution is 1g:10-20mL, and the ultrasonic treatment power is 150-300W, the temperature is 45-55℃, and the time is 1-3h.

[0009] As a further aspect of the present invention: the concentration of the sodium hydroxide solution is 8-15 wt%, and the ratio of the enzymatic hydrolyzed angelica powder to the sodium hydroxide solution is 1 g: 8-15 mL.

[0010] As a further aspect of the present invention: the low-temperature extraction temperature is 0-10℃ and the time is 30-60 min, and the heating and stirring extraction temperature is 80-95℃ and the time is 60-120 min.

[0011] As a further aspect of the present invention: the bleaching solution is a mixture of sodium chlorite solution and acetic acid solution, wherein the concentration of sodium chlorite solution is 1.5-2.5 wt%, the concentration of acetic acid solution is 2-4 wt%, and the material-to-liquid ratio of alkali-extracted cellulose to the bleaching solution is 1 g: 12-20 mL.

[0012] As a further aspect of the present invention: the mass of the disodium ethylenediaminetetraacetate is 0.5-1% of the mass of the bleaching solution.

[0013] The beneficial effects of this invention are: The extraction process for high-efficiency cellulose extraction from *Hemiberlesia lataniae* provided by this invention includes the steps of raw material pretreatment, degreasing and dewaxing, enzymatic hydrolysis and ultrasonication, segmented temperature-controlled alkali extraction, and complexation bleaching and refining. The obtained *Hemiberlesia lataniae* cellulose has a high α-cellulose content, moderate degree of polymerization, and good reactivity, and can be directly used for alkalization, xanthation, and dissolution to prepare viscose solutions. This provides a new, efficient, green, and high-value-added approach for the resource utilization of gramineous herbaceous fibers. The extraction process for high-efficiency cellulose extraction from *Hemiberlesia lataniae* provided by this invention uses readily available herbaceous resources as raw materials, turning waste into treasure and increasing added value. Furthermore, the overall chemical reagent usage is controllable, the conditions are mild, and the wastewater load is relatively low. Compared with the traditional one-step strong acid and strong alkali method, it is more environmentally friendly, combining ecological and economic benefits.

[0014] The extraction process for high-efficiency cellulose extraction from *Hemiberlesia lataniae* provided by this invention first involves washing, removing impurities, drying, and pulverizing the raw material to remove non-fibrous impurities such as mud, sand, humus, and coarse fiber bundles, resulting in uniform particle size and increased specific surface area, which is beneficial for subsequent solvent penetration and mass transfer in the reaction. Then, petroleum ether is added for Soxhlet reflux degreasing and dewaxing at 80-90℃ for 6-9 hours to directionally remove lipids, waxes, pigments, and fat-soluble impurities from the raw material, preventing them from encapsulating fibers and hindering enzymatic hydrolysis and alkaline extraction, while preserving the cellulose crystal structure, thus laying the foundation for subsequent high-purity extraction.

[0015] The extraction process provided by this invention also includes an enzymatic hydrolysis step, employing a composite enzyme system composed of pectinase and xylanase, combined with ultrasound-assisted treatment, to degrade non-cellulose polysaccharides such as pectin and hemicellulose in plant cell walls, efficiently breaking down cell walls without degrading the cellulose backbone. The ultrasound treatment step shortens the enzymatic hydrolysis time and reduces the amount of enzyme used, achieving efficient cell wall disruption under mild conditions of 45-55℃ and pH 4.5-5.5. Compared with traditional high-temperature and high-pressure chemical methods, this method results in higher retention of cellulose polymerization degree, less loss of crystallinity, and higher activity of the obtained fibers.

[0016] The alkali extraction process provided by this invention involves first performing cold alkali soaking at a low temperature of 0-10℃ to allow the alkali solution to fully penetrate and swell the fiber, dissolving some hemicellulose and small molecule lignin. This avoids the direct degradation, yellowing, and rapid drop in polymerization degree of cellulose caused by high temperature and strong alkali. Then, the temperature is rapidly raised to 80-95℃ for high-temperature extraction to enhance the removal of remaining hemicellulose, lignin, ash, and other impurities. By using segmented temperature-controlled alkali extraction, the purity and whiteness of cellulose can be significantly improved, while retaining a good degree of polymerization and reactivity, making it more suitable for subsequent preparation of viscose solutions.

[0017] The extraction process provided by this invention further involves complexation bleaching after alkaline extraction. Sodium chlorite is used for bleaching under weakly acidic conditions, selectively oxidizing and degrading residual lignin and pigments. This bleaching process is gentle and has minimal impact on cellulose strength. Disodium EDTA is then added to chelate and remove metal ions, inorganic salts, and ash from the system, reducing the adverse effects of metal ions on the color and thermal stability of cellulose and improving its purity and stability. After multi-stage washing with dilute alkali, hot water, and deionized water, the obtained cellulose has high whiteness, low ash content, and few chemical impurities, with a quality close to that of cotton pulp. This improves the uniformity, stability, filterability, and spinnability of the subsequent viscose solution preparation, significantly enhancing the quality of the finished viscose fiber. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1: The extraction process for high-efficiency cellulose extraction from *Heliotropium indicum* includes the following steps: After washing 500g of raw *Agrostis stenoptera* with tap water to remove mud, sand and surface impurities, it was dried in a 60℃ forced-air drying oven until constant weight. The dried *Agrostis stenoptera* was then pulverized using a pulverizer and passed through a 50-mesh standard sieve to obtain *Agrostis stenoptera* powder. Wrap the above 200g of *Hypericum perforatum* powder in filter paper and place it in a Soxhlet extractor. Add 1000mL of petroleum ether and reflux in an 85℃ water bath for 8 hours. After extraction, place it in a fume hood for 24 hours until the petroleum ether completely evaporates to obtain dewaxed *Hypericum perforatum* powder, weighing approximately 185g. Add 3000 mL of acetate-sodium acetate buffer solution with a pH of 5.0 to a 5 L reactor, add 60 g of pectinase (2.0% by mass) and 30 g of xylanase (1.0% by mass), and stir until completely dissolved to obtain a composite enzyme solution. Add 180 g of the above dewaxed sedge powder to the above composite enzyme solution and sonicate at 50 °C, ultrasonic power 300 W, and frequency 28 kHz for 2 h. After treatment, filter with a plate and frame filter press. Wash the filter residue three times with 2000 mL of deionized water at 40 °C each time until the pH test paper shows neutrality. Then vacuum dry at 60 °C to constant weight to obtain enzymatically hydrolyzed sedge powder. Add 150g of the above-mentioned enzymatically hydrolyzed *Achyranthes bidentata* powder to 2000mL of a 12% sodium hydroxide solution pre-cooled to 5℃. After low-temperature extraction at 5℃ and 150r / min for 45min, rapidly raise the temperature to 90℃ at a rate of 8℃ / min and continue stirring for 90min. After extraction, vacuum filter the solution while it is still hot using a 200-mesh filter cloth. Wash the filter residue twice with 1500mL of water each time to obtain alkali-extracted cellulose. The above-mentioned 280g of alkali-extracted cellulose (containing approximately 80g of dry matter) was dispersed in 1600mL of a bleaching solution containing 32g of sodium chlorite (to make the sodium chlorite mass fraction in the bleaching solution 2.0%) and 48mL of glacial acetic acid (to make the acetic acid mass fraction approximately 3.0%). The solution was stirred and bleached in a 75℃ water bath for 1.5h. Then, 12.8g of disodium ethylenediaminetetraacetate (0.8% of the total mass of the bleaching solution) was added, and the reaction was continued for 30min. After the reaction was completed, the solution was filtered. The filter residue was first washed once with 500mL of 0.5% dilute sodium hydroxide solution, then washed twice with 500mL of 60℃ hot water each time, and then washed with deionized water until the pH of the filtrate was 7.0. Finally, the solution was dried to constant weight in a vacuum drying oven at 50℃ to obtain sphagnum moss cellulose.

[0020] Example 2: The extraction process for high-efficiency cellulose extraction from *Gynostemma pentaphyllum* includes the following steps: After washing 500g of raw grass with tap water to remove mud, sand and surface impurities, place it in a 60℃ forced-air drying oven to dry to constant weight. Then, crush the dried grass with a pulverizer and pass it through a 40-mesh standard sieve to obtain grass powder. Wrap the above 200g of *Hypericum perforatum* powder in filter paper and place it in a Soxhlet extractor. Add 1000mL of petroleum ether and reflux in an 80℃ water bath for 9 hours. After extraction, place it in a fume hood for 24 hours until the petroleum ether completely evaporates to obtain dewaxed *Hypericum perforatum* powder, weighing approximately 185g. Add 3000 mL of acetate-sodium acetate buffer solution with a pH of 5.0 to a 5 L reactor, add 45 g of pectinase (1.5% by mass) and 15 g of xylanase (1.0% by mass), and stir until completely dissolved to obtain a composite enzyme solution. Add 180 g of the above dewaxed sedge powder to the above composite enzyme solution and sonicate at 45 °C, ultrasonic power 200 W, and frequency 25 kHz for 3 h. After treatment, filter with a plate and frame filter press. Wash the filter residue three times with 2000 mL of deionized water at 40 °C each time until the pH test paper shows neutrality. Then vacuum dry at 60 °C to constant weight to obtain enzymatically hydrolyzed sedge powder. Add 150g of the above-mentioned enzymatically hydrolyzed *Achyranthes bidentata* powder to 2000mL of a 15% sodium hydroxide solution pre-cooled to 5℃. After low-temperature extraction at 0℃ and 200r / min for 60min, rapidly raise the temperature to 95℃ at a rate of 5℃ / min and continue stirring for 120min. After extraction, vacuum filter the solution while it is still hot using a 200-mesh filter cloth. Wash the filter residue twice with 60℃ hot water, using 1500mL of water each time, to obtain alkaline-extracted cellulose. The above-mentioned 280g of alkali-extracted cellulose (containing approximately 80g of dry matter) was dispersed in 1600mL of a bleaching solution containing 40g of sodium chlorite (making the mass fraction of sodium chlorite in the bleaching solution 2.5%) and 64mL of glacial acetic acid (making the mass fraction of acetic acid approximately 4.0%). The solution was stirred and bleached in an 80℃ water bath for 1 hour. Then, 13.6g of disodium ethylenediaminetetraacetate (0.8% of the total mass of the bleaching solution) was added, and the reaction was continued for 30 minutes. After the reaction was completed, the solution was filtered. The filter residue was first washed once with 500mL of 0.5% dilute sodium hydroxide solution, then washed twice with 500mL of 60℃ hot water each time, and then washed with deionized water until the pH of the filtrate was 7.0. Finally, the solution was dried to constant weight in a vacuum drying oven at 50℃ to obtain sedge cellulose.

[0021] Example 3: The extraction process for high-efficiency cellulose extraction from *Gynostemma pentaphyllum* includes the following steps: After washing 500g of raw grass with tap water to remove mud, sand and surface impurities, place it in a 60℃ forced-air drying oven to dry to constant weight. Then, crush the dried grass with a pulverizer and pass it through a 40-mesh standard sieve to obtain grass powder. Wrap the above 200g of *Hypericum perforatum* powder in filter paper and place it in a Soxhlet extractor. Add 1000mL of petroleum ether and reflux in a 90℃ water bath for 6 hours. After extraction, place it in a fume hood for 24 hours until the petroleum ether is completely evaporated to obtain dewaxed *Hypericum perforatum* powder, weighing approximately 185g. Add 3000 mL of acetate-sodium acetate buffer solution with a pH of 5.0 to a 5 L reactor, add 75 g of pectinase (2.5% by mass) and 45 g of xylanase (1.5% by mass), and stir until completely dissolved to obtain a composite enzyme solution. Add 180 g of the above dewaxed sedge powder to the above composite enzyme solution and sonicate at 55 °C, ultrasonic power 400 W, and frequency 40 kHz for 1.5 h. After treatment, filter with a plate and frame filter press. Wash the filter residue three times with 2000 mL of deionized water at 40 °C each time until the pH test paper shows neutrality. Then vacuum dry at 60 °C to constant weight to obtain enzymatically hydrolyzed sedge powder. Add 150g of the above-mentioned enzymatically hydrolyzed *Achyranthes bidentata* powder to 2000mL of 8% sodium hydroxide solution pre-cooled to 5℃. After low-temperature extraction at 10℃ and 150r / min for 30min, rapidly heat to 80℃ at a rate of 10℃ / min and continue stirring for 60min. After extraction, vacuum filter the solution while it is still hot using a 200-mesh filter cloth. Wash the filter residue twice with 1500mL of water each time to obtain alkali-extracted cellulose. The above-mentioned 280g of alkali-extracted cellulose (containing approximately 80g of dry matter) was dispersed in 1600mL of a bleaching solution containing 24g of sodium chlorite (making the mass fraction of sodium chlorite in the bleaching solution 1.5%) and 32mL of glacial acetic acid (making the mass fraction of acetic acid approximately 2.0%). The solution was stirred and bleached in an 80℃ water bath for 1 hour. Then, 8.28g of disodium ethylenediaminetetraacetate (0.5% of the total mass of the bleaching solution) was added, and the reaction was continued for 40 minutes. After the reaction was completed, the solution was filtered. The filter residue was first washed once with 500mL of 0.5% dilute sodium hydroxide solution, then washed twice with 500mL of 60℃ hot water each time, and then washed with deionized water until the pH of the filtrate was 7.0. Finally, the solution was dried to constant weight in a vacuum drying oven at 50℃ to obtain sedge cellulose.

[0022] Compared with Example 1, Comparative Example 1 omits the step of enzymatic hydrolysis of dewaxed sedge powder and directly adds dewaxed sedge powder to sodium hydroxide solution for extraction. The remaining components and preparation methods are completely consistent with those of Example 1.

[0023] Compared with Example 1, Comparative Example 2 omits the low-temperature extraction step in the alkaline extraction process and directly adds the enzymatically hydrolyzed *Achyranthes bidentata* powder to a sodium hydroxide solution for heating and stirring extraction. The remaining components and preparation methods are completely consistent with those of Example 1.

[0024] Compared with Example 1, Comparative Example 3 only differs in that it does not add disodium ethylenediaminetetraacetate to the bleaching solution, and is directly washed and dried after bleaching. The remaining components and preparation methods are completely consistent with those of Example 1.

[0025] Performance testing Cellulose extraction rate calculation: P = m1 / m0 × 100%; Where: P is the cellulose extraction rate, %; m0 is the mass of dewaxed *Hylocereus undatus* powder, g; m1 is the mass of *Hylocereus undatus* cellulose, g; the test results are shown in Table 1; Cellulose content calculation: Place the cellulose from *Strombax ceiba* into a clean, dry 250 mL Erlenmeyer flask. Add a nitric acid-ethanol mixture at a material-to-liquid ratio of 1:25 (g / mL). Attach a reflux condenser and incubate in a boiling water bath for 1 hour. Remove the solvent. Repeat this process three to five times until the fiber turns white. Wash the residue with an appropriate amount of nitric acid-ethanol mixture, then wash with hot water until neutral. Finally, wash twice with anhydrous ethanol and dry to constant weight. The calculation formula is: C=(m1×m2) / (m0×m1)×100%; In the formula: m0 is the mass of dewaxed *Agrostis stenoptera* powder, g; m1 is the mass of *Agrostis stenoptera* cellulose, g (dry weight); m2 is the mass of *Agrostis stenoptera* cellulose after treatment with a nitric acid-ethanol mixture, g (dry weight); C is the cellulose content, %; the test results are shown in Table 1. Cellulose viscosity test: Take about 10g of sample, dissolve it in 100mL of water, stir into a slurry, filter it into 3 uniform slurry cakes on a Buchner funnel, place them in an oven at 105℃ and dry to constant weight, take them out and place them in a desiccator, cool to room temperature and then conduct the test. Based on the volume of the brown bottle containing the copper ammonia solution, calculate the required sample mass using the following formula: m = ρV / (1-W) In the formula: m is the sample amount, g; ρ is the mass concentration of the cellulose copper ammonia solution, ρ=0.01g / mL; V is the volume of the brown bottle containing the copper ammonia solution, mL; W is the analytical moisture mass fraction of the sample, %, W=0, i.e., measured on an absolutely dry basis.

[0026] The viscosity of cellulose cuprammonium is calculated using the following formula: η=ρtK; Where: η is the dynamic viscosity, mPa·s; ρ is the density of the cellulose copper ammonia solution, ρ=0.97g / mL; t is the outflow time of the sample solution, s; K is the correction coefficient of the capillary viscometer; the test results are shown in Table 1; Antibacterial performance test: The *Gynostemma pentaphyllum* cellulose sample was irradiated with a light source of 50W and a wavelength of 420nm for 30 minutes. Antibacterial performance tests were conducted on the light-treated composite fiber sample, the pure viscose fiber sample, and the untreated composite fiber sample VF-5 according to GB / 20944.3-2088 "Evaluation of Antibacterial Properties of Textiles Part 3: Oscillation Method". *Staphylococcus aureus*, *Escherichia coli*, and *Candida albicans* were selected as experimental strains. The antibacterial rate was calculated using the following formula: Y = (W t -Q t ) / W t ×100%; In the formula: Y is the antibacterial rate, %; W t Q represents the average colony growth of the control sample after 18 hours of shaking incubation; t The average value of colony growth after shaking culture of composite fiber samples for 18 hours is shown in Table 1. Table 1: Statistical Table of Cellulose Performance Test Data of Examples 1-3 and Comparative Examples 1-3 As shown in Table 1, the *Gynostemma pentaphyllum* cellulose prepared by the high-efficiency extraction process provided in Examples 1-3 of this invention exhibits high polymerization degree, low degradation degree, and excellent antibacterial properties. In Comparative Example 1, the enzymatic hydrolysis step was omitted, resulting in a significant decrease in the extraction rate and content of *Gynostemma pentaphyllum* cellulose, as well as a decrease in copper-ammonia viscosity. This indicates that enzymatic hydrolysis not only helps improve extraction efficiency but also opens the cell wall under mild conditions, reducing damage to cellulose from subsequent alkali treatment, thereby preserving a higher degree of polymerization. In Comparative Example 2, the low-temperature extraction step in the alkali extraction process was omitted, resulting in a significant decrease in the copper-ammonia viscosity of the obtained *Gynostemma pentaphyllum* cellulose, indicating that direct high-temperature alkali extraction leads to severe cellulose degradation. In Comparative Example 3, no disodium EDTA was added during the bleaching process, resulting in a slight decrease in the copper-ammonia viscosity of the obtained *Gynostemma pentaphyllum* cellulose, as well as a slight decrease in whiteness and antibacterial rate. This indicates that by complexing metal ions, the oxidative degradation of cellulose during bleaching is reduced, helping to maintain the polymerization degree and stability of cellulose.

[0027] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0028] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A highly efficient extraction process for cellulose from *Agrostis chinensis*, characterized in that, At least the following steps are included: After washing, removing impurities, drying, and pulverizing, the grass is obtained as grass powder. The powdered agarwood was added to petroleum ether and refluxed to obtain dewaxed agarwood powder. The dewaxed *Achyranthes bidentata* powder was added to a compound enzyme solution, ultrasonically treated, filtered, washed and dried to obtain enzymatically hydrolyzed *Achyranthes bidentata* powder. The enzymatically hydrolyzed *Achyranthes bidentata* powder was added to a sodium hydroxide solution, extracted at low temperature, then heated and stirred for further extraction and filtration to obtain alkali-extracted cellulose residue. The alkali-extracted cellulose residue was dispersed in a bleaching solution, stirred, and then disodium ethylenediaminetetraacetate was added. The mixture was stirred, filtered, washed, and dried to obtain sedge cellulose.

2. The extraction process for high-efficiency cellulose extraction from *Gynostemma pentaphyllum* according to claim 1, characterized in that, The particle size of the *Achyranthes bidentata* powder is 40-60 mesh, the ratio of the *Achyranthes bidentata* powder to the petroleum ether is 1g:8-12mL, and the reflux treatment temperature is 80-90℃ for 6-9h.

3. The extraction process for high-efficiency cellulose extraction from *Gynostemma pentaphyllum* according to claim 1, characterized in that, The composite enzyme solution is a mixed solution of pectinase and xylanase, wherein the concentration of pectinase is 1.5-2.5 wt%, the concentration of xylanase is 0.5-1.5 wt%, and the pH value of the composite enzyme solution is 4-6.

4. The extraction process for high-efficiency cellulose extraction from *Gynostemma pentaphyllum* according to claim 1, characterized in that, The ratio of the dewaxed dandelion powder to the compound enzyme solution is 1g:10-20mL, and the ultrasonic treatment power is 150-300W, the temperature is 45-55℃, and the time is 1-3h.

5. The extraction process for high-efficiency cellulose extraction from *Gynostemma pentaphyllum* according to claim 1, characterized in that, The concentration of the sodium hydroxide solution is 8-15 wt%, and the ratio of the enzymatic hydrolyzed *Clerodendrum trichotomum* powder to the sodium hydroxide solution is 1 g: 8-15 mL.

6. The extraction process for high-efficiency cellulose extraction from *Gynostemma pentaphyllum* according to claim 1, characterized in that, The low-temperature extraction is performed at a temperature of 0-10℃ for 30-60 minutes, while the heating and stirring extraction is performed at a temperature of 80-95℃ for 60-120 minutes.

7. The extraction process for high-efficiency cellulose extraction from *Gynostemma pentaphyllum* according to claim 1, characterized in that, The bleaching solution is a mixture of sodium chlorite solution and acetic acid solution, wherein the concentration of sodium chlorite solution is 1.5-2.5 wt%, the concentration of acetic acid solution is 2-4 wt%, and the material-to-liquid ratio of alkali-extracted cellulose to the bleaching solution is 1 g: 12-20 mL.

8. The extraction process for high-efficiency cellulose extraction from *Gynostemma pentaphyllum* according to claim 1, characterized in that, The mass of the disodium ethylenediaminetetraacetate is 0.5-1% of the mass of the bleaching solution.

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