Method for removing bast sizing material by using compound enzyme

Abstract

The invention discloses a method for removing a bast sizing material by using a compound enzyme, which belongs to the technical field of pulping and papermaking pretreatment, and is characterized by comprising the following steps of: 1) peeling off barks from trunks or branches, and peeling and removing an outer skin layer; (2) putting the peeled bast into a boiling water bath, and cooking for 1 hour; 3) putting the soaked bark into a compound enzyme solution with the temperature of 40-60 DEG C and the pH value of 4-7, and treating for 2-6 hours, wherein the compound enzyme solution comprises pectinase, cutinase and xylanase; and 4) continuously stirring through a magnetic stirrer in the enzyme treatment process. According to the method, the compound enzyme method is adopted to remove the sizing material in the bark, so that the damage to fibers in the chemical degumming process can be reduced; meanwhile, the pulping performance of the fiber can be improved, the treated enzyme liquid can be repeatedly used, the discharge and treatment capacity of wastewater are reduced, and the pollution to the environment is reduced.

Description

Technical Field

[0001] The invention relates to a method for degumming bast, and more specifically to a method for pretreating bast papermaking raw materials with biological enzymes. Background Art

[0002] As the largest natural plant fiber, wood provides abundant raw materials for the pulp and paper industry. In traditional industrial production, the pretreatment of plant materials usually involves chemical methods, such as degumming under strong alkali or acidic conditions. However, these chemical methods may produce waste and have a negative impact on the environment. Therefore, the development of bio-enzyme degumming technology has received widespread attention. In recent years, the degumming treatment of bast fiber has gradually attracted people's attention, but the raw materials targeted are relatively single and not universal. For example, Chinese patent application CN202310395640.6 (publication number CN116732618A, publication date September 12, 2023) discloses a bio-enzyme degumming process for hemp fiber degumming, which removes the colloid on the surface of hemp fiber by bio-enzyme treatment; and another Chinese patent application CN200610044256.8 (publication number CN1858343A, publication date November 8, 2006) discloses a "method for preparing light leaf paper pulp for making viscose fiber", which is a pulp raw material for making viscose fiber from paper mulberry bast. In addition, some existing biological methods also take a long time and have relatively low efficacy. For example, the "biological enzyme degumming method for tree bast fiber" disclosed in Chinese patent CN200810025684.5 (publication number CN101215718, publication date 2008.07.09) is to first treat the fiber with an acidic enzyme solution, or with an alkaline enzyme solution to achieve the purpose of tree bast degumming, which basically takes about 10 hours. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a rapid and simple bio-enzyme degumming method for bast fiber, which can retain the fiber quality and reduce wastewater pollution, in view of the above-mentioned deficiencies in the prior art.

[0004] The technical solution of the present invention is as follows:

[0005] A method for removing bast rubber by using a composite enzyme comprises the following steps:

[0006] 1) Peeling bark off a tree trunk or branch and removing the outer layer of bark;

[0007] 2) Place the peeled bast in a boiling water bath and cook for 1 hour;

[0008] 3) Then, the soaked bark is placed in a compound enzyme solution at a temperature of 40 to 60°C and a pH of 4 to 7 for 2 to 6 hours;

[0009] 4) Continuous stirring was performed by a magnetic stirrer during the enzyme treatment.

[0010] In the above-mentioned method of removing bast rubber with a composite enzyme, in step 1), for three-year-old trees, the old bark on the bark surface is removed mechanically, and then the bast layer is separated from the tree trunk manually or by a barking machine; while for branches or shrubs grown within one year, the bast can be directly peeled off manually or by a barking machine for later use.

[0011] In the above-mentioned method for removing bast rubber with a composite enzyme, the deionized water used in step 2) is homemade in the laboratory and completely immerses the bast.

[0012] In the above-mentioned method for removing bast glue with a composite enzyme, the solid-liquid ratio of bast to enzyme solution in step 3) is 1g:10-20mL, wherein the bast is calculated based on the absolute dry weight, and the optimal condition is 1g:20mL.

[0013] In the above-mentioned method for removing bast rubber with a compound enzyme, the optimal compound enzyme in step 3) contains 2g / L pectinase, 1g / L xylanase, and 1g / L cutinase, and is treated at pH 6.8 and 50°C for 4 hours.

[0014] In the above-mentioned method for removing bast rubber by using a composite enzyme, during the enzyme treatment in step 4), continuous stirring is performed at a speed of 200-500 rpm using a magnetic stirrer.

[0015] The present invention provides a method for removing the size in the bast by the above-mentioned treatment method to obtain raw pulp suitable for pulping and papermaking.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] (1) The method adopted by the present invention is a biological enzyme treatment method. Compared with the chemical treatment method, it reduces the damage to the bast fiber during the chemical degumming process and retains the original properties of the fiber. At the same time, the enzyme solution can be reused, reducing pollution to the environment.

[0018] (2) The present invention is applicable to a wide range of raw materials and has strong universality.

[0019] (3) The present invention adopts a one-stage complex enzyme treatment, which takes a short time and is simple to operate, and is suitable for industrial rapid production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an optical microscope observation of bast fiber after bio-enzyme degumming. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. If the manufacturer of the reagents or instruments used is not indicated, they are deemed to be conventional products that can be purchased commercially.

[0022] Example 1

[0023] (1) Removing the bark: Take freshly cut mulberry branches and manually separate the bark from the branch stem, trying to avoid bringing in the hard wood fiber layer inside the branch.

[0024] (2) Cold water immersion treatment: The bark of the tree branches was placed in boiling water and boiled for 1 h. The deionized water used in this example was homemade in the laboratory.

[0025] (3) Compound enzyme solution treatment: The bark treated with cold water was placed in a neutral enzyme solution at a temperature of 50°C and pH 6.8 at a bath ratio of 1:30 for 4 hours. The pectinase and xylanase used in this example were purchased from Shanghai MacLean Co., Ltd., and the cutinase used was from Ruichenxing Biotechnology (Guangzhou) Co., Ltd., where the concentrations of pectinase, cutinase, and xylanase were 2 g / L, 1 g / L, and 1 g / L, respectively.

[0026] (4) During the enzyme solution treatment process, continuous stirring is performed at a speed of 200-500 rpm using a magnetic stirrer to promote the contact reaction between the enzyme solution and the phloem.

[0027] After the reaction is completed, the bark is filtered, washed, freeze-dried and other processes to form pulp for papermaking. The filtrate after treatment is collected and inactivated at high temperature and then the sugar content is determined.

[0028] Example 2

[0029] (1) Removing the bark: Take freshly cut mulberry branches and manually separate the bark from the branch stem, trying to avoid bringing in the hard wood fiber layer inside the branch.

[0030] (2) Cold water immersion treatment: The bark of the tree branches was placed in boiling water and boiled for 1 h. The deionized water used in this example was homemade in the laboratory.

[0031] (3) Compound enzyme solution treatment: The bark treated with cold water was placed in a neutral enzyme solution at a temperature of 50°C and pH 6.8 at a bath ratio of 1:30 for 4 hours. The pectinase and xylanase used in this example were purchased from Shanghai MacLean Co., Ltd., where the concentrations of pectinase and xylanase were 2 g / L and 1 g / L, respectively.

[0032] (4) During the enzyme solution treatment process, continuous stirring is performed at a speed of 200-500 rpm using a magnetic stirrer to promote the contact reaction between the enzyme solution and the phloem.

[0033] After the reaction is completed, the bark is filtered, washed, freeze-dried and other processes to form pulp for papermaking. The filtrate after treatment is collected and inactivated at high temperature and then the sugar content is determined.

[0034] Example 3

[0035] (1) Removing the bark: Take freshly cut mulberry branches and manually separate the bark from the branch stem, trying to avoid bringing in the hard wood fiber layer inside the branch.

[0036] (2) Cold water immersion treatment: The bark of the tree branches was placed in boiling water and boiled for 1 h. The deionized water used in this example was homemade in the laboratory.

[0037] (3) Compound enzyme solution treatment: The bark treated with cold water was placed in a neutral enzyme solution at a temperature of 50°C and pH 6.8 at a bath ratio of 1:30 for 4 hours. The pectinase used in this example was purchased from Shanghai MacLean Co., Ltd., and the cutinase used was from Ruichenxing Biotechnology (Guangzhou) Co., Ltd., where the pectinase and cutinase were 2 g / L and 1 g / L, respectively.

[0038] (4) During the enzyme solution treatment process, continuous stirring is performed at a speed of 200-500 rpm using a magnetic stirrer to promote the contact reaction between the enzyme solution and the phloem.

[0039] After the reaction is completed, the bark is filtered, washed, freeze-dried and other processes to form pulp for papermaking. The filtrate after treatment is collected and inactivated at high temperature and then the monosaccharide content is determined.

[0040] Comparative Example 1

[0041] (1) Removing the bark: Take freshly cut mulberry branches and manually separate the bark from the branch stem, trying to avoid bringing in the hard wood fiber layer inside the branch.

[0042] (2) Cold water immersion treatment: The bark of the tree branches was placed in boiling water and boiled for 1 h. The deionized water used in this example was homemade in the laboratory.

[0043] (3) Treatment with compound enzyme solution: The bark that has been soaked in cold water is placed in a neutral enzyme solution at a temperature of 50°C and a pH of 6.8 at a bath ratio of 1:30 for 4 hours.

[0044] (4) During the enzyme solution treatment process, continuous stirring is performed at a speed of 200-500 rpm using a magnetic stirrer to promote the contact reaction between the enzyme solution and the phloem.

[0045] After the reaction is completed, the bark is filtered, washed, freeze-dried and other processes to form pulp for papermaking. The filtrate after treatment is collected and inactivated at high temperature and then the monosaccharide content is determined.

[0046] The monosaccharide content in the solution after enzymatic hydrolysis (calculated based on the original 1g of bark) was determined by ion chromatography. The results are shown in Table 1:

[0047]

[0048] Table 1

[0049] As can be seen from Table 1, compared with comparative case 1, the addition of biological enzymes allows more aldehyde acid and sugars to be released from the bark. Under the optimal conditions, the amount of aldehyde acid released reaches 8.09 mg / L, which indicates that the treatment with the compound enzymes has greatly reduced the pectin in the bark, and the removal of pectin makes the fiber easier to use in the future. It can be seen that the use of compound enzymes can effectively remove the glue in the bast fiber, providing a basis for the use of bast fibers such as bark in the field of pulping and papermaking.

[0050] The above embodiments are only preferred implementation modes of the present invention and are only used to explain the present invention rather than to limit the present invention. Any changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for removing bast rubber by using a composite enzyme, characterized in that The steps include: 1) Peeling bark off a tree trunk or branch and removing the outer layer of bark; 2) Place the peeled bast in a boiling water bath and cook for 1 hour; 3) Then, the soaked bark is placed in a compound enzyme solution at a temperature of 40 to 60°C and a pH of 4 to 7 for 2 to 6 hours; 4) Continuous stirring was performed by a magnetic stirrer during the enzyme treatment.

2. The method for removing bast rubber by using a composite enzyme according to claim 1, characterized in that: The bark used in step (1) is one of paper mulberry, mulberry, celtis sinensis and smilax china.

3. The method for removing bast rubber by using a composite enzyme according to claim 1, characterized in that: In step (3), the solid-liquid ratio of bast to enzyme solution is 1 g:10-20 mL, wherein the bast is calculated based on the absolute dry weight.

4. The method for removing bast rubber by using a composite enzyme according to claim 1, characterized in that: In step (3), the reaction temperature of bast and complex enzyme is 40-60°C, wherein the optimum temperature is 50°C.

5. The method for removing bast rubber by using a composite enzyme according to claim 1, characterized in that: In step (3), the pH of the reaction between the bark and the complex enzyme is 4-7, wherein the optimal pH is 6.

8.

6. The method for removing bast rubber by using a composite enzyme according to claim 1, characterized in that: In step (3), the enzyme solution comprises cutinase, pectinase and xylanase, and the concentrations of the cutinase, pectinase and xylanase are 1-2 g / L, 1-2 g / L and 1 g / L respectively.

7. The method for removing bast rubber by using a composite enzyme according to claim 1, characterized in that: In step (3), the reaction time of the complex enzyme and the bark is 2 to 6 hours, and the optimal reaction time is 4 hours.

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