Method for preparing biological eucommia rubber from primary fermented eucommia bark
By employing a method involving single-stage rolling, deep freezing, urea fermentation, and enzymatic hydrolysis, the high energy consumption and poor quality of the gum extracted from Eucommia bark in existing technologies have been resolved. This method achieves efficient and low-energy extraction of Eucommia gum, resulting in high-quality Eucommia gum.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUHAN ZIWUYUAN SCI & TECH
- Filing Date
- 2026-03-24
- Publication Date
- 2026-06-19
AI Technical Summary
In existing technologies, when extracting eucommia gum from eucommia bark, the crushing step causes the high-polymerization-degree long-chain eucommia gum filaments to become short chains. Strong acid or strong alkali treatment results in high energy consumption, a large amount of waste liquid, and damage to the gum filaments, affecting the quality of the eucommia gum.
The method employs a single rolling pressing, deep freezing, urea fermentation, and enzymatic hydrolysis process. Rolling pressing softens the bark of Eucommia ulmoides and increases its exposed area, freezing destroys the cell walls, and after fermentation, urea solution and enzymatic ultrasonic treatment are used to remove cellulose and lignin. Finally, Eucommia ulmoides gum is extracted using organic solvents.
To obtain high-quality Eucommia gum, the adverse effects of strong acids and alkalis are avoided, and the extraction efficiency and extraction rate are improved. Eucommia gum has long gum fibers and excellent physical properties.
Abstract
Description
Technical Field
[0001] This invention relates to a process for extracting high-molecular-weight Eucommia gum from natural raw materials, specifically to a method for preparing bio-Eucommia gum from fermented Eucommia bark. Background Technology
[0002] Eucommia ulmoides gum is an excellent polymer material with dual rubber-plastic properties. Broadly speaking, it is divided into two categories: natural eucommia ulmoides rubber and synthetic eucommia ulmoides rubber. Both have the same chemical composition as natural rubber from the rubber tree (Hevea brasiliensis), but their molecular structures differ. Eucommia ulmoides gum is trans-polyisoprene, while natural rubber is cis-polyisoprene. Eucommia ulmoides is a precious economic tree species unique to China and one of the most widely used and important collagen-producing plants in the world. The leaves, bark, and fruit peel of Eucommia ulmoides are rich in a white, filamentous substance—eucommia ulmoides gum. The discovery of the unique "rubber-plastic duality" of eucommia ulmoides gum has expanded its application fields.
[0003] Eucommia bark is a traditional Chinese medicine with the effects of tonifying the liver and kidneys, strengthening muscles and bones, and calming the fetus. Currently, besides its use as a medicinal herb, Eucommia bark is also a high-quality raw material for extracting Eucommia gum. Eucommia bark is the bark of the Eucommia tree, and it is more difficult to extract Eucommia gum from it than from Eucommia leaves and fruits, which also contain Eucommia gum components, because its texture is relatively hard and rich in cellulose and lignin. Current techniques for extracting Eucommia gum from Eucommia leaves, bark, or fruit generally involve steps such as drying, pulverizing, enzymatic hydrolysis (or strong acid / alkali decomposition), organic solvent extraction, and cooling or alcohol precipitation. The drawbacks of existing Eucommia gum extraction techniques are: the pulverizing step transforms the originally highly polymerized long-chain Eucommia gum filaments into short chains, affecting the physical properties of the extracted Eucommia gum; strong acid or alkali treatment is generally accompanied by high-temperature cooking (100℃), which not only consumes a lot of energy and produces a lot of waste liquid, but also damages the gum filaments to some extent, resulting in poor-quality Eucommia gum. Therefore, it is necessary to study and provide a new method for extracting Eucommia gum, especially a method for extracting Eucommia bark raw material, which is difficult to extract. Summary of the Invention
[0004] This invention provides a method for preparing bio-eucommia gum from fermented Eucommia bark, aiming to overcome the above-mentioned shortcomings in the prior art.
[0005] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A method for preparing bio-eucommia gum from fermented Eucommia bark, comprising the following steps:
[0006] S1. First roll pressing: The freshly harvested Eucommia bark is fed into a double roll press and pressed. After pressing, the Eucommia bark becomes thinner and initially softens. The juice extracted by pressing is collected and refrigerated for later use.
[0007] S2. Deep freezing: Immerse the Eucommia bark treated in S1 in water until thoroughly soaked, then remove and drain. Place it in a freezer at -18°C or below for deep freezing treatment. After it is thoroughly frozen, remove it from the freezer and thaw it to room temperature for later use.
[0008] S3. Secondary Rolling and Fermentation: The thawed Eucommia bark from S2 is fed back into the roller press for rolling. The rolled Eucommia bark becomes thinner and softer. The juice extracted from the roller press is mixed with the juice stored in S1 to obtain a juice mixture. Urea solution is added to the juice mixture to obtain a spraying liquid. The spraying liquid is then evenly sprayed onto the Eucommia bark after the secondary rolling. Finally, the Eucommia bark is piled up and allowed to ferment naturally.
[0009] S4. Enzymatic hydrolysis: The fermented Eucommia bark is put into the pre-prepared enzymatic hydrolysate, the enzymatic hydrolysis temperature is controlled at 40-45℃, and the enzymatic hydrolysis is carried out by ultrasonication for 24-38 hours. After filtration, the filter residue is collected for later use.
[0010] S5. Extraction and separation: The filter residue from S4 is added to an organic solvent and heated under reflux to fully dissolve the Eucommia gum fibers. Then, the mixture is filtered, and the filtrate is frozen to precipitate. The mixture is filtered again, and the filtrate is reused. The precipitate obtained from the filtration is Eucommia gum.
[0011] Based on the above technical solution, the present invention can also make the following further specific choices or better choices.
[0012] Specifically, in S1, each piece of fresh Eucommia bark undergoes at least two stages of rolling during the rolling process in the roller press. During the first stage of rolling, the gap between the two pairs of rollers is controlled at 3-4 mm. During the second stage of rolling, the gap between the two pairs of rollers is controlled at 1.5-2.5 mm. The length of the fresh Eucommia bark along the axial direction of the tree is 10-20 cm. During the rolling process, the fresh Eucommia bark is unfolded and fed into the roller press along the axial direction.
[0013] Specifically, in S2, the Eucommia bark is soaked in water for at least 45 minutes to allow it to fully absorb water and become thoroughly soaked.
[0014] Specifically, during the deep freezing process in S2, the temperature inside the freezer is controlled between -25°C and -18°C. Thorough freezing means ensuring that the temperature inside and outside the Eucommia bark is consistent with the temperature inside the freezer.
[0015] Specifically, in S3, each piece of Eucommia bark undergoes at least one rolling process during the rolling process in the roller mill, and the gap between the two pairs of rollers in this rolling process is controlled to be 0.6-1.2mm.
[0016] Specifically, the concentration of urea solution in S3 is 20-25wt%, the mass ratio of juice mixture to urea is 1:3-5, the dosage ratio of Eucommia bark to spray solution is 1g:0.2-0.4mL, after the Eucommia bark is piled up and covered with a film, it is allowed to ferment naturally more than twice. Each fermentation lasts for 18-24 hours and the fermentation temperature is controlled not to exceed 60℃. After each fermentation, the pile is opened and ventilated at room temperature for 5-10 hours.
[0017] Specifically, the concentration of cellulase in the enzymatic hydrolysate of S4 is 0.28-0.35 wt%, the concentration of ligninase is 0.4-0.5 wt%, and the pH is controlled at 4-5.
[0018] Specifically, during ultrasonic enzymatic hydrolysis in S4, the ultrasonic power is 450-550W, and the frequency is preferably 25-30KHz.
[0019] Specifically, the organic solvent used in S5 is petroleum ether or chloroform, the reflux temperature is 65-80℃, and the reflux time is 4-6h.
[0020] Specifically, in S5, filtrate freezing precipitation refers to lowering the filtrate temperature to 0°C and maintaining it for more than 1 hour.
[0021] Compared with the prior art, the beneficial effects of the present invention are:
[0022] This invention involves a first rolling process, deep freezing after immersion in water, and a second rolling process on fresh Eucommia bark. This process loosens and softens the cellulose and lignin structure of the bark, increasing its exposed surface area. Simultaneously, the rolling and freezing processes cause moderate cell wall damage, releasing nutrients such as polysaccharides, amino acids, vitamins, and minerals along with the juice extracted during rolling. After the second rolling, the nutrient-rich juice mixture is mixed with a urea solution and sprayed onto the pre-treated bark surface. This results in a richer nutrient content on the bark surface, facilitating more efficient fermentation during subsequent pile fermentation and promoting faster and better initial consumption of cellulose and lignin. After fermentation, the bark undergoes further enzymatic and ultrasonic treatment to remove cellulose and lignin, fully releasing the Eucommia gum fibers. Finally, the gum is dissolved and extracted using an organic solvent, followed by cooling and precipitation to obtain high-quality Eucommia gum.
[0023] No strong acids or alkalis were used during the entire extraction process, and the fresh Eucommia bark was not dried or pulverized. As a result, the extracted Eucommia gum fibers were longer. At the same time, the Eucommia gum was not adversely affected by strong alkalis, strong acids, and high temperatures, resulting in high-quality Eucommia gum. Pretreatments such as rolling, freezing, fermentation, and spraying followed by fermentation made ultrasonic enzymatic hydrolysis more efficient and thorough, thus ensuring a high Eucommia gum extraction rate. Detailed Implementation
[0024] The technical solutions provided by the present invention will be clearly and completely described below with reference to specific embodiments. 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.
[0025] Unless otherwise specified, all raw materials used in the following examples are commercially available products, and all methods used are conventional methods in the art.
[0026] It should be noted that the fresh Eucommia bark used in the following embodiments of the present invention is preferably fresh bark that has been harvested from the Eucommia tree within one month and has not been dried. If the harvested Eucommia bark is older than one month and has a moisture content of less than 50%, it should be moistened with water before roller pressing to ensure that the moisture content of the bark is above 65%. In the following embodiments, the length of the fresh Eucommia bark used along the axial direction of the tree is 10-20 cm (preferably by girdling). During roller pressing, the fresh Eucommia bark is spread out and fed into the roller press along the axial direction. The ligninase in the enzymatic hydrolysate used in the following embodiments is preferably laccase.
[0027] Example 1
[0028] A method for preparing bio-eucommia gum from fermented Eucommia bark includes the following steps:
[0029] S1. First rolling: The freshly harvested Eucommia bark is fed into a double-roller press and rolled. After at least two stages of rolling, the gap between the two pairs of rollers is controlled at 3mm during the first stage of rolling and 1.5mm during the second stage of rolling. The Eucommia bark becomes thinner and softens initially after rolling. The juice extracted by rolling is collected and refrigerated for later use.
[0030] S2. Deep freezing: Immerse the Eucommia bark treated in S1 in water for more than 45 minutes. After soaking, remove and drain. Then place it in a freezer at -18°C for deep freezing for 1-2 hours. After it is fully frozen (the temperature inside and outside of the Eucommia bark reaches the set temperature in the freezer, the same below), remove it from the freezer and thaw it to room temperature for later use.
[0031] S3. Secondary Rolling and Fermentation: The thawed Eucommia bark from S2 is fed back into the roller press for at least one stage of rolling, with the gap between the two pairs of rollers controlled at 0.6 mm. The rolled Eucommia bark becomes thinner and softer. The juice extracted from the roller press is mixed with the juice stored in S1 to obtain a juice mixture. Urea aqueous solution is added to the juice mixture to obtain a spray solution with a concentration of 20 wt% and a mass ratio of juice mixture to urea of 1:5. The spray solution is then evenly sprayed onto the Eucommia bark after the secondary rolling, with a ratio of Eucommia bark to spray solution of 1 g: 0.4 mL. Finally, the Eucommia bark is piled up, covered with a thin film, and allowed to ferment naturally at least twice. Each fermentation lasts for 22 hours, and the fermentation temperature is controlled not to exceed 60°C. After each fermentation, the pile is opened and ventilated at room temperature for 8 hours.
[0032] S4. Enzymatic hydrolysis: The fermented Eucommia bark is put into the pre-prepared enzymatic hydrolysate. The concentration of cellulase in the enzymatic hydrolysate is 0.28wt%, the concentration of ligninase is 0.4wt%, the pH is controlled at 4, the enzymatic hydrolysis temperature is controlled at 40℃, and the enzymatic hydrolysis is performed by ultrasonication for 30h with an ultrasonic power of 500W. After filtration, the filter residue is collected for later use.
[0033] S5. Extraction and separation: Add the filter residue from S4 to the organic solvent petroleum ether or chloroform, heat and reflux to fully dissolve the Eucommia ulmoides gum fibers. The reflux temperature is 80℃ and the reflux time is 4h. After reflux, filter while hot, then cool the filtrate to 0℃ and maintain it for more than 1h to allow the dissolved and extracted Eucommia ulmoides gum to precipitate. Filter again, reuse the filtrate, and the precipitate is Eucommia ulmoides gum.
[0034] Example 2
[0035] A method for preparing bio-eucommia gum from fermented Eucommia bark includes the following steps:
[0036] S1. First rolling: The freshly harvested Eucommia bark is fed into a double-roller press and rolled. After at least two stages of rolling, the gap between the two pairs of rollers is controlled at 3mm during the first stage of rolling and 1.8mm during the second stage of rolling. The Eucommia bark becomes thinner and softens initially after rolling. The juice extracted by rolling is collected and refrigerated for later use.
[0037] S2. Deep freezing: Immerse the Eucommia bark treated in S1 in water for more than 45 minutes. After soaking, remove and drain. Then place it in a freezer at -25°C for deep freezing for 1-2 hours. After freezing, remove it from the freezer and thaw it to room temperature for later use.
[0038] S3. Secondary Rolling and Fermentation: The thawed Eucommia bark from S2 is fed back into the roller press for at least one stage of rolling, with the gap between the two pairs of rollers controlled at 0.8 mm. The rolled Eucommia bark becomes thinner and softer. The juice extracted from the roller press is mixed with the juice stored in S1 to obtain a juice mixture. Urea aqueous solution is added to the juice mixture to obtain a spray solution with a concentration of 23 wt% and a mass ratio of juice mixture to urea of 1:5. The spray solution is then evenly sprayed onto the Eucommia bark after the secondary rolling, with a ratio of Eucommia bark to spray solution of 1 g: 0.3 mL. Finally, the Eucommia bark is piled up, covered with a thin film, and allowed to ferment naturally at least twice. Each fermentation lasts for 20 hours, and the fermentation temperature is controlled not to exceed 60°C. After each fermentation, the pile is opened and ventilated at room temperature for 7 hours.
[0039] S4. Enzymatic hydrolysis: The fermented Eucommia bark is put into the pre-prepared enzymatic hydrolysate. The concentration of cellulase in the enzymatic hydrolysate is 0.35wt%, the concentration of ligninase is 0.5wt%, the pH is controlled at 5, the enzymatic hydrolysis temperature is controlled at 45℃, and the enzymatic hydrolysis is carried out by ultrasonication for 38 hours with an ultrasonic power of 450W. After filtration, the filter residue is collected for later use.
[0040] S5. Extraction and separation: Add the filter residue from S4 to the organic solvent petroleum ether or chloroform, heat and reflux to fully dissolve the Eucommia ulmoides gum fibers. The reflux temperature is 65℃ and the reflux time is 6h. Then filter, cool the filtrate to 0℃ and maintain it for more than 1h to allow the dissolved and extracted Eucommia ulmoides gum to precipitate. Filter again, reuse the filtrate, and the precipitate is Eucommia ulmoides gum.
[0041] Example 3
[0042] A method for preparing bio-eucommia gum from fermented Eucommia bark includes the following steps:
[0043] S1. First rolling: The freshly harvested Eucommia bark is fed into a double-roller press and rolled. After at least two stages of rolling, the gap between the two pairs of rollers is controlled at 4mm during the first stage of rolling and 2mm during the second stage of rolling. The Eucommia bark becomes thinner and softens initially after rolling. The juice extracted by rolling is collected and refrigerated for later use.
[0044] S2. Deep freezing: Immerse the Eucommia bark treated in S1 in water for more than 45 minutes. After soaking, remove and drain. Then place it in a freezer at -20°C for deep freezing for 1-2 hours. After freezing, remove it from the freezer and thaw it to room temperature for later use.
[0045] S3. Secondary Rolling and Fermentation: The thawed Eucommia bark from S2 is fed back into the roller press for at least one stage of rolling, with the gap between the two pairs of rollers controlled at 1.1 mm. The rolled Eucommia bark becomes thinner and softer. The juice extracted from the roller press is mixed with the juice stored in S1 to obtain a juice mixture. Urea aqueous solution is added to the juice mixture to obtain a spray solution with a concentration of 20 wt% and a mass ratio of juice mixture to urea of 1:4. The spray solution is then evenly sprayed onto the Eucommia bark after the secondary rolling, with a ratio of Eucommia bark to spray solution of 1 g: 0.2 mL. Finally, the Eucommia bark is piled up, covered with a thin film, and allowed to ferment naturally at least twice. Each fermentation lasts for 18 hours, and the fermentation temperature is controlled not to exceed 60°C. After each fermentation, the pile is opened and ventilated at room temperature for 5 hours.
[0046] S4. Enzymatic hydrolysis: The fermented Eucommia bark is put into the pre-prepared enzymatic hydrolysate. The concentration of cellulase in the enzymatic hydrolysate is 0.3wt%, the concentration of ligninase is 0.4wt%, the pH is controlled at 4, the enzymatic hydrolysis temperature is controlled at 40℃, and the enzymatic hydrolysis is carried out by ultrasonic hydrolysis for 24 hours with an ultrasonic power of 550W. After filtration, the filter residue is collected for later use.
[0047] S5. Extraction and separation: Add the filter residue from S4 to the organic solvent petroleum ether or chloroform, heat and reflux to fully dissolve the Eucommia ulmoides gum fibers. The reflux temperature is 75℃ and the reflux time is 5h. Then filter, cool the filtrate to 0℃ and maintain it for more than 1h to allow the dissolved and extracted Eucommia ulmoides gum to precipitate. Filter again, reuse the filtrate, and the precipitate is Eucommia ulmoides gum.
[0048] Example 4
[0049] A method for preparing bio-eucommia gum from fermented Eucommia bark includes the following steps:
[0050] S1. First rolling: The freshly harvested Eucommia bark is fed into a double-roller press and rolled. After at least two stages of rolling, the gap between the two pairs of rollers is controlled at 4mm during the first stage of rolling and 2.5mm during the second stage of rolling. The Eucommia bark becomes thinner and softens initially after rolling. The juice extracted by rolling is collected and refrigerated for later use.
[0051] S2. Deep freezing: Immerse the Eucommia bark treated in S1 in water for more than 45 minutes. After soaking, remove and drain. Then place it in a freezer at -25°C for deep freezing for 1-2 hours. After freezing, remove it from the freezer and thaw it to room temperature for later use.
[0052] S3. Secondary Rolling and Fermentation: The thawed Eucommia bark from S2 is fed back into the roller press for at least one stage of rolling, with the gap between the two pairs of rollers controlled at 1.2 mm. The rolled Eucommia bark becomes thinner and softer. The juice extracted from the roller press is mixed with the juice stored in S1 to obtain a juice mixture. Urea aqueous solution is added to the juice mixture to obtain a spray solution with a concentration of 25 wt% and a mass ratio of juice mixture to urea of 1:3. The spray solution is then evenly sprayed onto the Eucommia bark after the secondary rolling, with a ratio of Eucommia bark to spray solution of 1 g: 0.2 mL. Finally, the Eucommia bark is piled up, covered with a thin film, and allowed to ferment naturally at least twice. Each fermentation lasts for 24 hours, and the fermentation temperature is controlled not to exceed 60°C. After each fermentation, the pile is opened and ventilated at room temperature for 10 hours.
[0053] S4. Enzymatic hydrolysis: The fermented Eucommia bark is put into the pre-prepared enzymatic hydrolysate. The concentration of cellulase in the enzymatic hydrolysate is 0.35wt%, the concentration of ligninase is 0.4wt%, the pH is controlled at 4, the enzymatic hydrolysis temperature is controlled at 42℃, and the enzymatic hydrolysis is performed by ultrasonication for 35 hours with an ultrasonic power of 450W. After filtration, the filter residue is collected for later use.
[0054] S5. Extraction and separation: Add the filter residue from S4 to the organic solvent petroleum ether or chloroform, heat and reflux to fully dissolve the Eucommia ulmoides gum fibers. The reflux temperature is 70℃ and the reflux time is 6h. Then filter, cool the filtrate to 0℃ and maintain it for more than 1h to allow the dissolved and extracted Eucommia ulmoides gum to precipitate. Filter again, reuse the filtrate, and filter out the precipitate as Eucommia ulmoides gum.
[0055] Comparative Example 1
[0056] It is basically the same as Example 1, except that the first rolling process in S1 and the second rolling process in S3 are missing. Instead, the fresh Eucommia bark is directly subjected to deep freezing treatment in S2, and the spraying liquid in the fermentation step in S3 is replaced with a 20wt% urea aqueous solution.
[0057] Comparative Example 2
[0058] It is basically the same as Example 1, except that the deep freezing treatment of S2 is missing. After the first rolling is completed, the rolled Eucommia bark is directly subjected to the second rolling and fermentation treatment of S3.
[0059] Comparative Example 3
[0060] It is basically the same as Example 1, except that the enzymatic hydrolysis treatment of S4 is missing and extraction and separation are carried out directly after the fermentation of S3.
[0061] Comparative Example 4
[0062] It is basically the same as Example 1, except that the secondary rolling process of S3 is missing, and the Eucommia bark after S2 is directly subjected to the fermentation process of S3.
[0063] It should be noted that the Eucommia bark used in Examples 1 to 4 and Comparative Examples 1 to 4 was harvested from Eucommia trees in the same region and of similar age. The methods disclosed in each example and comparative example involved dividing the fresh Eucommia bark from which Eucommia gum was to be extracted into multiple groups and repeating the process according to the corresponding example or comparative example. The average extraction rate of Eucommia gum for each example and comparative example was then calculated. The extraction rate was expressed as the weight ratio of the extracted Eucommia gum to the fresh Eucommia bark (with a moisture content of approximately 65%). The results showed that the average extraction rate of Eucommia gum corresponding to Examples 1 to 4 was between 4-6%, while the average extraction rate corresponding to Comparative Examples 1 to 4 was all below 2%. Clearly, the extraction method provided by this invention has a certain synergistic effect among its steps; the absence of any step or part of a step would lead to a significant decrease in the extraction rate.
[0064] In addition, this invention also uses a conventional process of drying and pulverizing Eucommia bark before extraction (Chinese Invention Patent CN201210307899.2) to extract Eucommia gum from the same batch of Eucommia bark raw materials. The results show that, under the premise of using the ratio of extracted Eucommia gum to fresh Eucommia bark as the Eucommia gum extraction rate, the average extraction rate of this method of drying and pulverizing before extraction is about 4%, which is close to the lower limit of the average extraction rate of each embodiment of this invention. However, because it involves ultra-fine pulverization of Eucommia bark, the molecular weight of the obtained Eucommia gum is lower, and its physical properties such as tensile strength, elasticity and toughness are significantly worse than those of the Eucommia gum extracted in Examples 1 to 4 of this invention. The Eucommia gum extracted by the method provided by this invention is of better quality.
[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing bio-eucommia gum from fermented Eucommia bark, characterized in that, Includes the following steps: S1. First roll pressing: The freshly harvested Eucommia bark is fed into a double roll press and pressed. After pressing, the Eucommia bark becomes thinner and softens initially. The juice extracted from the press is collected and refrigerated for later use. S2. Deep freezing: Immerse the Eucommia bark treated in S1 in water until thoroughly soaked, then remove and drain. Place it in a freezer at -18°C or below for deep freezing treatment. After it is thoroughly frozen, remove it from the freezer and thaw it to room temperature for later use. S3. Secondary Rolling and Fermentation: The thawed Eucommia bark from S2 is fed back into the roller press for rolling. The rolled Eucommia bark becomes thinner and softer. The juice extracted from the roller press is mixed with the juice stored in S1 to obtain a juice mixture. Urea solution is added to the juice mixture to obtain a spraying liquid. The spraying liquid is then evenly sprayed onto the Eucommia bark after the secondary rolling. Finally, the Eucommia bark is piled up and allowed to ferment naturally. S4. Enzymatic hydrolysis: The fermented Eucommia bark is put into the pre-prepared enzymatic hydrolysate, the enzymatic hydrolysis temperature is controlled at 40-45℃, and the enzymatic hydrolysis is carried out by ultrasonication for 24-38 hours. After filtration, the filter residue is collected for later use. S5. Extraction and separation: The filter residue from S4 is added to an organic solvent and heated under reflux to fully dissolve the Eucommia gum fibers. Then, the mixture is filtered, and the filtrate is frozen to precipitate. The mixture is filtered again, and the filtrate is reused. The precipitate obtained from the filtration is Eucommia gum.
2. The method for preparing bio-eucommia gum from fermented Eucommia bark according to claim 1, characterized in that, In S1, each piece of fresh Eucommia bark undergoes at least two stages of rolling during the rolling process in the double roller mill. During the first stage of rolling, the gap between the two pairs of rollers is controlled at 3-4 mm. During the second stage of rolling, the gap between the two pairs of rollers is controlled at 1.5-2.5 mm. The length of the fresh Eucommia bark along the axial direction of the tree is 10-20 cm. During rolling, the fresh Eucommia bark is unfolded and fed into the double roller mill along the axial direction.
3. The method for preparing bio-eucommia gum from fermented Eucommia bark according to claim 1, characterized in that, In S2, the Eucommia bark is immersed in water for at least 45 minutes to allow it to fully absorb water and become thoroughly soaked.
4. The method for preparing bio-eucommia gum from fermented Eucommia bark according to claim 1, characterized in that, During the deep freezing process in S2, the temperature inside the freezer is controlled between -25°C and -18°C. Thorough freezing means that the temperature inside and outside the Eucommia bark is consistent with the temperature inside the freezer.
5. The method for preparing bio-eucommia gum from fermented Eucommia bark according to claim 1, characterized in that, In S3, each piece of Eucommia bark undergoes at least one rolling process during the rolling mill, and the gap between the two pairs of rollers in this rolling process is controlled to be 0.6-1.2mm.
6. The method for preparing bio-eucommia gum from fermented Eucommia bark according to claim 1, characterized in that, The concentration of urea solution in S3 is 20-25wt%, the mass ratio of juice mixture to urea is 1:3-5, the ratio of Eucommia bark to spray solution is 1g:0.2-0.4mL, after the Eucommia bark is piled up, it is covered with a film and allowed to ferment naturally more than twice. Each fermentation lasts for 18-24 hours and the fermentation temperature is controlled not to exceed 60℃. After each fermentation, the pile is opened and ventilated at room temperature for 5-10 hours.
7. The method for preparing bio-eucommia gum from fermented Eucommia bark according to claim 1, characterized in that, In S4, the concentration of cellulase in the enzymatic hydrolysate is 0.28-0.35 wt%, the concentration of ligninase is 0.4-0.5 wt%, and the pH is controlled at 4-5.
8. The method for preparing bio-eucommia gum from fermented Eucommia bark according to claim 1, characterized in that, During ultrasonic enzymatic hydrolysis in S4, the ultrasonic power is 450-550W.
9. The method for preparing bio-eucommia gum from fermented Eucommia bark according to claim 1, characterized in that, The organic solvent used in S5 is petroleum ether or chloroform, the reflux temperature is 65-80℃, and the reflux time is 4-6h.
10. A method for preparing bio-eucommia gum from fermented Eucommia bark according to any one of claims 1 to 9, characterized in that, In S5, filtrate freezing precipitation refers to lowering the filtrate temperature to 0°C and maintaining it for more than 1 hour.