Method for improving permeability of raw bamboo skin
The waxy layer and lignin of the epidermis of the original bamboo are removed by combining lipase and laccase, improving its permeability and porosity, solving the problem of hydrophobicity of the original bamboo is hindered from the penetration of the modifier, and achieving environmentally friendly and low-cost The modification effect enhances the anti-mold and anti-corrosion performance of bamboo.
Patent Information
- Application Number
- CN202411507600.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2024-12-10
AI Technical Summary
The hydrophobicity of the original bamboo skin hinders the penetration of the modifier, making it difficult to effectively improve its anti-mold, anti-corrosion and cracking properties. The existing treatment methods such as microwave or supercritical CO2 treatment equipment are complex and costly, and alkali cooking technology contaminates the environment. And change the color of the bamboo.
Through the combined treatment of lipase and laccase, the waxy layer of the original bamboo is removed and lignin is degraded, the hydrophilicity and porosity of its epidermis are improved, and the treatment parameters are optimized using phosphate buffering system and enzymatic conditions, including pH, temperature and Time to ensure processing effect.
It significantly improves the permeability and hydrophilicity of the original bamboo skin, reduces processing costs, and is environmentally friendly and pollution-free. The modifier can penetrate into the inside of the bamboo more effectively, enhancing its anti-mold and anti-corrosion properties.
Smart Images
Figure CN119099008A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of raw bamboo processing, and in particular to a method for improving the permeability of raw bamboo epidermis. Background Art
[0002] Bamboo is a renewable biomass resource widely distributed in China. Due to its renewability, low cost and sustainability, bamboo is considered to be one of the most important alternatives in green and energy-saving buildings. Since 2013, China has issued a series of policy documents, including the Green Building Action Plan, the Action Plan for Promoting the Production and Application of Green Building Materials and the National New Urbanization Plan (2014-2020). Bamboo structures and bamboo engineering materials have been officially recognized and included in the field of green buildings and environmentally sustainable materials. However, raw bamboo has problems such as easy mildew, decay and cracking. Before using it as an engineering material, it needs to be modified to improve its mildew, corrosion and cracking resistance. At the same time, the raw bamboo used in bamboo buildings is usually 7-8 meters long, and due to the presence of bamboo nodes, it is difficult for the modifier to enter the middle part from the end. Therefore, it is necessary to improve the lateral permeability of the raw bamboo skin so that the modifier can directly penetrate into the raw bamboo through the bamboo skin. However, there is a strong hydrophobic bamboo wax on the raw bamboo skin, which hinders the penetration of the modifier.
[0003] At present, the industry mainly processes bamboo through microwave or supercritical CO2, which has complex equipment and high cost. In addition, alkali boiling technology is also commonly used in the market, which will produce a large amount of wastewater and pollute the environment. After alkali boiling, the original bamboo will change from green to yellow, losing its natural color. Summary of the invention
[0004] The purpose of the present invention is to provide a method for improving the permeability of raw bamboo skin. The present invention effectively improves the permeability and hydrophilicity of raw bamboo skin through the combined treatment of lipase and laccase, and has the characteristics of low processing cost and environmental protection.
[0005] The technical solution provided by the present invention is as follows: a method for improving the permeability of raw bamboo epidermis, using lipase to enzymatically hydrolyze the raw bamboo to remove its wax layer, thereby obtaining lipase-treated raw bamboo with exposed stomata; then using laccase to enzymatically hydrolyze the lipase-treated raw bamboo to degrade and dissolve its lignin, thereby obtaining bio-enzyme-treated raw bamboo with pores.
[0006] In the above method for improving the permeability of raw bamboo skin, the lipase enzymatic treatment of raw bamboo includes: preparing a phosphate buffer system, adjusting the pH to 6-9, then adding lipase, mixing evenly, adding raw bamboo, and finally heating for enzymatic hydrolysis.
[0007] In the aforementioned method for improving the permeability of raw bamboo skin, the lipase is added at a concentration of 50-150 U / g.
[0008] In the aforementioned method for improving the permeability of raw bamboo skin, the lipase is added at a concentration of 150 U / g.
[0009] In the aforementioned method for improving the permeability of raw bamboo skin, the lipase enzymolysis temperature is 25-55° C., the enzymolysis time is 6-25 hours, and stirring is continued during the enzymolysis process.
[0010] In the aforementioned method for improving the permeability of raw bamboo skin, the enzymatic hydrolysis temperature is 40° C. and the enzymatic hydrolysis time is 24 hours.
[0011] In the above method for improving the permeability of raw bamboo skin, the laccase enzymatic hydrolysis treatment of raw bamboo treated with lipase specifically includes: preparing a phosphate buffer solution, adjusting the pH to 4-6, adding laccase, mixing evenly, adding raw bamboo treated with lipase, and heating for enzymatic hydrolysis.
[0012] In the aforementioned method for improving the permeability of raw bamboo epidermis, the laccase is added at a concentration of 0.2-0.4 U / mL.
[0013] In the aforementioned method for improving the permeability of raw bamboo epidermis, the concentration of laccase added is 0.237 U / mL.
[0014] In the aforementioned method for improving the permeability of raw bamboo skin, the enzymatic hydrolysis temperature of the laccase is 45° C., the heating enzymatic hydrolysis time is 24 hours, and stirring is continued during the process.
[0015] Compared with the prior art, the present invention uses lipase to perform enzymatic hydrolysis on raw bamboo to remove its wax layer, thereby obtaining lipase-treated raw bamboo with exposed pores. After the hydrophobic wax layer is removed, the hydrophilicity of the raw bamboo epidermis can be improved, and the permeability is also improved after the pores are exposed; laccase is used to perform enzymatic hydrolysis on the lipase-treated raw bamboo to degrade and dissolve its lignin, thereby obtaining bio-enzyme-treated raw bamboo with pores, thereby further improving its permeability. The lipase and laccase used in the present invention have low material costs, and no pollutants are generated during the action process, which is green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 Schematic diagram of the water contact angle of the raw bamboo skin of untreated raw bamboo, buffer treatment group, lipase treatment group and lipase-laccase combined treatment group;
[0017] Figure 2 The results of water contact angle of untreated raw bamboo and raw bamboo treated with different lipase concentrations;
[0018] Figure 3 The contact angle results of untreated raw bamboo and raw bamboo treated with lipase-laccase;
[0019] Figure 4These are the microscopic morphological characteristics of untreated raw bamboo, raw bamboo treated with lipase, and raw bamboo treated with lipase-laccase combined. DETAILED DESCRIPTION
[0020] The present invention is further described below in conjunction with the embodiments and drawings, but they are not intended to limit the present invention.
[0021] Example 1: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 6 (by preparing 0.2 mol / L KH2PO4 and Na2HPO4), adding lipase with a concentration of 50 U / g into the phosphate buffer system and mixing evenly, adding the raw bamboo into the phosphate buffer system, performing enzymolysis at 25°C for 6 hours, stirring continuously during the process, using lipase enzymolysis to remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 4, adding ABTS laccase medium and laccase with a concentration of 0.2 U / mL into the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo.
[0022] Example 2: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 7, adding lipase with a concentration of 100 U / g into the phosphate buffer system and mixing evenly, adding the raw bamboo into the phosphate buffer system, performing enzymolysis at 35°C for 12 hours, stirring continuously during the process, using lipase to remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 4.5, adding ABTS laccase medium and laccase with a concentration of 0.25 U / mL into the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo.
[0023] Example 3: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 8, adding lipase with a concentration of 100 U / g into the phosphate buffer system and mixing evenly, adding the raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using lipase to remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 4.5, adding ABTS laccase medium and laccase with a concentration of 0.3 U / mL into the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo.
[0024] Example 4: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 8, adding lipase with a concentration of 100 U / g into the phosphate buffer system and mixing evenly, adding the raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using lipase to remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 4.5, adding ABTS laccase medium and laccase with a concentration of 0.3 U / mL into the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo.
[0025] Example 5: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 9, adding lipase with a concentration of 150 U / g into the phosphate buffer system and mixing evenly, adding the raw bamboo into the phosphate buffer system, performing enzymolysis at 45°C for 24 hours, stirring continuously during the process, using lipase to remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 5, adding ABTS laccase medium and laccase with a concentration of 0.25 U / mL into the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo.
[0026] Example 6: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 8, adding lipase with a concentration of 150 U / g into the phosphate buffer system and mixing evenly, adding the raw bamboo into the phosphate buffer system, performing enzymolysis at 50°C for 24 hours, stirring continuously during the process, using lipase to remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 6, adding ABTS laccase medium and laccase with a concentration of 0.24 U / mL into the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo.
[0027] Example 7: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 8.5, adding lipase with a concentration of 150 U / g into the phosphate buffer system and mixing evenly, adding the raw bamboo into the phosphate buffer system, performing enzymolysis at 55°C for 24 hours, stirring continuously during the process, using lipase to remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 4, adding ABTS laccase medium and laccase with a concentration of 0.22 U / mL into the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo.
[0028] Example 8: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 8.5, adding lipase at a concentration of 150U / g to the phosphate buffer system and mixing evenly, adding the raw bamboo to the phosphate buffer system, performing enzymolysis at 45°C for 12 hours, stirring continuously during the process, using lipase to enzymolyze and remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 5, adding ABTS laccase medium and laccase at a concentration of 0.23U / mL to the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo to the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo
[0029] Example 9: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 8.5, adding lipase at a concentration of 150U / g to the phosphate buffer system and mixing evenly, adding the raw bamboo to the phosphate buffer system, performing enzymolysis at 50°C for 12 hours, stirring continuously during the process, using lipase to enzymolyze and remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 4.5, adding ABTS laccase medium and laccase at a concentration of 0.235U / mL to the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo to the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo
[0030] Example 10: A method for improving the permeability of raw bamboo epidermis, preparing a phosphate buffer system with a pH of 8.5, adding lipase with a concentration of 150 U / g into the phosphate buffer system and mixing evenly, adding the raw bamboo into the phosphate buffer system, performing enzymolysis at 40°C for 24 hours, stirring continuously during the process, using lipase to remove the wax layer of the raw bamboo, and rinsing with water to obtain lipase-treated raw bamboo with exposed stomata; preparing a phosphate buffer system with a pH of 4.5, adding ABTS laccase medium and laccase with a concentration of 0.237 U / mL into the phosphate buffer system and mixing evenly, adding the lipase-treated raw bamboo into the phosphate buffer system, performing enzymolysis at 45°C for 24 hours, stirring continuously during the process, using laccase to degrade and dissolve the lignin of the lipase-treated raw bamboo, and rinsing with water to obtain the bio-enzyme-treated raw bamboo.
[0031] In order to further verify the optimal parameters of the method for improving the permeability of raw bamboo epidermis, the following experiment was carried out, setting up untreated raw bamboo (blank group), alkali boiling treatment group and lipase treatment group, laccase treatment group and lipase-laccase combined treatment group. The product was dried in an oven at 60°C to constant weight, and then the raw bamboo was sealed on all sides with epoxy resin, leaving only the bamboo epidermis outside, and then immersed in water, the water weight gain rate was calculated, and the water contact angle was measured by instrument.
[0032] The lipase dosage of the lipase treatment group was fixed at 50 U / g, and the pH of the phosphate buffer system, treatment temperature, treatment time, and the soaking weight gain rate after the experiment were shown in Table 1 below.
[0033]
[0034] Table 1
[0035] From the above table, we can see that the order of the three factors affecting weight gain rate is pH>temperature>time. The best treatment process is to place the raw bamboo in a phosphate buffer system with a pH of 8.5 and perform lipase enzymolysis at 40°C for 24 hours. Figure 1 As shown in the figure, the contact angle of the original bamboo skin of the untreated material is about 105.9°, while the contact angle of the original bamboo treated with pH 8.5 buffer solution only drops to 97.5°. At the same time, the contact angle of the original bamboo skin treated with lipase is as high as 73.5°, which is 32.4° lower than that of the untreated material, indicating that lipase treatment can change the wettability of the original bamboo skin and improve its hydrophilicity.
[0036] The buffer pH was determined to be 8.5, the treatment temperature was 40°C, the treatment time was 24 h, and according to the lipase activity, the lipase concentrations of the lipase treatment group were set to 50 U / g, 100 U / g, 150 U / g, and a blank group without lipase was added. The weight gain rate of the original bamboo epidermis after soaking in water for 168 h is shown in Table 2 below.
[0037] Lipase concentration (U / g) Weight gain rate after soaking in water for 168 hours (%) Blank group 6.37 50 8.02 100 11.75 150 19.38
[0038] Table 2
[0039] As can be seen from the table above, with the increase of lipase concentration, the weight gain rate of the original bamboo skin increased to varying degrees. The weight gain rate of the blank group untreated bamboo after 168 hours of soaking was 6.37%, while the weight gain rate after 150U / g lipase treatment reached 19.38%, an increase of 13.01%. Figure 2 As shown in the figure, with the increase of lipase concentration, the water contact angle continued to decrease. The water contact angle of the blank group was 105.9°, while the water contact angle after treatment with 150U / g lipase decreased to 73.5°, a decrease of 32.4°, proving that the hydrophilicity of the original bamboo skin was improved after treatment. Therefore, the lipase concentration was determined to be 150U / g.
[0040] The laccase concentrations of the laccase treatment groups were set to 0.2U / mL, 0.23U / mL, 0.237U / mL, 0.24U / mL, 0.27U / mL, 0.3U / mL, and 0.4U / mL, and the blank group without lipase was added. The weight gain rate of the original bamboo skin soaked in water for 168 hours is shown in Table 3 below;
[0041] Laccase concentration (U / mL) Weight gain rate after soaking in water for 168 hours (%) Blank group 6.37 0.2 8.33 0.23 9.62 0.237 11.28 0.24 11.03 0.27 10.28 0.3 9.41 0.4 8.52
[0042] Table 3
[0043] It can be seen from the above table that with the increase of laccase concentration, the weight gain rate of the original bamboo skin increased to varying degrees, reaching the peak value in the 0.237U / mL group, so the laccase concentration was determined to be 0.237U / mL.
[0044] The lab values of untreated raw bamboo, alkali-treated raw bamboo and lipase-treated raw bamboo were measured, as shown in Table 3 below.
[0045] L* a* b* ΔE Original bamboo 40.60 -4.57 17.55 Alkali cooking of raw bamboo 67.24 4.15 25.89 29.25 Lipase treated raw bamboo 34.98 0.69 12.21 9.37
[0046] Table 4
[0047] The ΔE of the raw bamboo after lipase treatment is smaller than that of the raw bamboo treated with alkali, indicating that the color of the raw bamboo after lipase treatment is closer to the color of the raw bamboo itself. At the same time, a* represents the red-green axis chromaticity index in the Lab color system. A positive value indicates that the color is reddish, and a negative value indicates that the color is greenish. The raw bamboo treated with lipase has a smaller a*, indicating that it is more green.
[0048] The weight gain rate of untreated raw bamboo, raw bamboo treated with lipase, raw bamboo treated with laccase, and raw bamboo treated with lipase-laccase combined treatment after soaking in water for 168 hours was measured. The results are shown in Table 4 below.
[0049] Table 5
[0050] Lipase treatment followed by laccase treatment further improved the permeability of the original bamboo skin, and the weight gain rate after 168 hours of soaking in water could reach 22.37%, which was 16.00% higher than that of the untreated original bamboo. Figure 3 As shown, the contact angles of HEMA (hydroxyethyl methacrylate), epoxy resin and mildew inhibitor on the original bamboo skin all decreased.
[0051] The porosity of the original bamboo, the original bamboo treated with lipase, the original bamboo treated with laccase, and the original bamboo treated with lipase-laccase combined treatment was measured by mercury intrusion, as shown in Table 5 below.
[0052] Table 6
[0053] The total pore area of the original bamboo skin is 28.42m 2 / g, the average pore size was 31.87nm, and the porosity was 28.70%. After being treated with lipase and laccase, the total pore area of the original bamboo epidermis increased to 47.59m 2 / g, the average pore size increased to 49.97nm, and the porosity increased to 42.65%, proving that the permeability was improved.
[0054] The original bamboo, the original bamboo treated with lipase and the original bamboo treated with lipase-laccase were observed by electron microscopy. Figure 4 As shown, the original bamboo epidermis is covered with a layer of wax. After lipase treatment, the wax layer is removed and the pores under the wax layer are exposed. After further laccase treatment, a large number of micron-level pores appear in the original bamboo epidermis due to the degradation and dissolution of lignin, which further increases the porosity of the bamboo epidermis.
[0055] In summary, the present invention uses lipase to perform enzymatic hydrolysis on raw bamboo to remove its wax layer, so as to obtain lipase-treated raw bamboo with exposed stomata. After the hydrophobic wax layer is removed, the hydrophilicity of the raw bamboo epidermis can be improved, and the permeability is also improved after the stomata are exposed; laccase is used to perform enzymatic hydrolysis on the lipase-treated raw bamboo to degrade and dissolve its lignin, so as to obtain bio-enzyme-treated raw bamboo with pores, and further improve its permeability; the material cost of lipase and laccase is low, and no pollutants are generated during the action process, which is green and environmentally friendly.
Claims
1. A method for improving the permeability of raw bamboo skin, characterized by: The original bamboo is enzymatically treated with lipase to remove its wax layer, thereby obtaining the lipase-treated original bamboo with exposed stomata; and the lipase-treated original bamboo is enzymatically treated with laccase to degrade and dissolve its lignin, thereby obtaining the bio-enzyme-treated original bamboo with pores.
2. The method for improving the permeability of raw bamboo skin according to claim 1, characterized in that: The lipase enzymatic hydrolysis treatment of raw bamboo comprises: preparing a phosphate buffer system, adjusting the pH to 6-9, then adding lipase, mixing evenly, adding raw bamboo, and finally heating for enzymatic hydrolysis.
3. The method for improving the permeability of raw bamboo skin according to claim 2, characterized in that: The lipase is added at a concentration of 50-150 U / g.
4. The method for improving the permeability of raw bamboo skin according to claim 3, characterized in that: The lipase addition concentration is 150 U / g.
5. The method for improving the permeability of raw bamboo skin according to claim 2, characterized in that: The lipase enzymolysis temperature is 25-55° C., the enzymolysis time is 6-25 hours, and stirring is continued during the enzymolysis process.
6. The method for improving the permeability of raw bamboo skin according to claim 5, characterized in that: The enzymolysis temperature is 40° C. and the enzymolysis time is 24 h.
7. The method for improving the permeability of raw bamboo skin according to claim 1, characterized in that: The enzymatic hydrolysis of lipase-treated raw bamboo by laccase specifically comprises: preparing a phosphate buffer system, adjusting the pH to 4-6, adding laccase, mixing evenly, adding lipase-treated raw bamboo, and heating for enzymatic hydrolysis.
8. The method for improving the permeability of raw bamboo skin according to claim 7, characterized in that: The laccase addition concentration is 0.2-0.4 U / mL.
9. The method for improving the permeability of raw bamboo skin according to claim 8, characterized in that: The laccase addition concentration was 0.237 U / mL.
10. The method for improving the permeability of raw bamboo skin according to claim 7, characterized in that: The enzymolysis temperature of the laccase is 45° C., the heating enzymolysis time is 24 h, and stirring is continued during the process.