LU500846B1

LU500846B1 - Method for pulping wheat straw by using xylanase and pectinase

Info

Publication number: LU500846B1
Application number: LU500846A
Authority: LU
Inventors: Kaiquan Liu; Xingxiang Ji; Piwu Li; Shan Wei; Ruiming Wang
Original assignee: Univ Qilu Technology
Priority date: 2021-06-11
Filing date: 2021-11-10
Publication date: 2022-05-10
Also published as: CN113265898A; CN113265898B

Abstract

The present disclosure belongs to the field of biotechnology and relates to a method for pulping wheat straw using xylanase and pectinase. The method comprises: swelling the wheat straw; and putting the swelled wheat straw in an alkaline solution after welling treatment, adjust the pH to neutral; under neutral conditions, use a mixture of xylanase and pectinase to enzymatically treat and grind the slurry treated with the alkaline solution to obtain. The pulping method of the present disclosure uses agricultural waste wheat straw as primary raw material, which is of great significance for the recycling of biomass resources. The combined treatment of xylanase and pectinase reduces the amount of chemical reagents and reduces energy consumption of pulping; at the same time, the cooking process of raw materials is cancelled, and the target grinding degree can be obtained under the conditions of normal temperature and pressure.

Description

METHOD FOR PULPING WHEAT STRAW BY USING XYLANASE AND LUS00846

PECTINASE TECHNICAL FIELD

[01] The present disclosure belongs to the field of biotechnology, and is a pulping method for wheat straw pulping using biological enzymes at normal temperature and pressure.

BACKGROUND ART

[02] Disclosure of the background information is only intended to increase the understanding of the overall background of the present present disclosure, and is not necessarily regarded as an acknowledgement or any form of suggestion that the information constitutes the prior art known to those of ordinary skill in the art.

[03] The paper industry is faced with global problems such as energy shortage, environmental pressure, and lack of papermaking raw materials, and it is in urgent need of reform and transformation. Since modern times, wood is the main raw material for papermaking. However, my country’s wood resources are increasingly scarce. In recent years, wood resources have become more and more dependent on imports. Therefore, it is necessary to speed up the search for other papermaking materials to replace wood to avoid uncontrolled forests. Deforestation and the ensuing ecological problems. The pollution of pulping with non-wood fiber raw materials is more serious than that of wood fiber raw materials. The waste liquid obtained from the pulping of non-wood fiber raw materials is generally recycled by the alkali method. Some materials in the waste liquid that can be reused are processed. recycle and re-use. However, "pollution first, then treatment" is not a good solution after all. Whether it is processing cost or manpower and material resources, it is a huge pressure for small-scale paper mills. Therefore, it is necessary to solve the problem from the root cause. From the beginning of the pulping process to improve, to reduce waste liquid pollution as much as possible, which is of great significance for environmental protection and human development.

[04] Mechanical pulping and chemical pulping are two pulping methods commonly used in the pulp and paper industry, and the two are often used in combination. The energy consumption of mechanical pulping is relatively high. Therefore, people have always demanded a pulping method that can effectively reduce energy consumption. In addition, due to the addition of chemical reagents in the chemical pulping process, many toxic substances are discharged in nature, and these toxic substances are extremely harmful to animals and humans.

[05] Biological enzyme preparations have the advantages of mild reaction conditions and high reaction efficiency, and can also achieve the purpose of saving resources and reducing pulping energy consumption in the pulp and paper industry. In addition, the addition of enzymes in the biological pulping process will increase the brightness of the pulp to a certain extent and improve the strength properties of the pulp. In short, the use of enzyme preparations to process pulping raw materials, the reaction process is simple and controllable, temperature and pH changes will not have too much influence on the degree of cellulose polymerization, the production cost is high, and overall, it is 1 possible to put into production Sex is greater. LU500846

SUMMARY

[06] In view of the environmental pollution and high energy consumption problems of chemical mechanical pulping, the present disclosure establishes a pulping method under normal temperature and pressure conditions based on actual conditions. The advantage of the pulping method is that the amount of chemical reagents added is reduced, thereby reducing the emission of harmful substances; at the same time, the addition of enzymes reduces the energy consumption of pulping.

[07] In order to achieve the above technical objectives, the present disclosure employs the following technical solutions:

[08] The first aspect of the present disclosure provides a method for pulping wheat straw using xylanase and pectinase, which comprises:

[09] Swelling treatment of wheat straw;

[10] Treating the swelled wheat straw in an alkaline solution, and then adjust pH to neutral;

[11] Under neutral conditions, using a mixture of xylanase and pectinase to enzymatically treat and grind a slurry after treated with the alkaline solution to obtain.

[12] It is found in the research that under normal temperature, pressure and neutral conditions, the use of a combination of swelling, KOH treatment and enzyme treatment for pulping has certain application value for reducing pulping pollution and reducing pulping energy consumption.

[13] The second aspect of the present disclosure provides a pulp prepared by any of the above methods.

[14] The third aspect of the present disclosure provides an application of the mixture of xylanase and pectinase in wheat straw pulping.

[15] The beneficial effects of the present disclosure are:

[16] (1) The pulping method of the present disclosure uses agricultural waste—wheat straw as primary raw material, which is of great significance to the recycling of biomass resources. The combined treatment of xylanase and pectinase reduces the amount of chemical reagents, reduce the energy consumption of pulping; at the same time, cancel the cooking process of the raw materials, and the target grinding degree can be obtained under the conditions of normal temperature and pressure.

[17] (2) The operation method of this application is simple, low cost, universal, and easy to scale production.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[18] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further descriptions of the present disclosure. Unless otherwise specified, all technical and scientific terms used in the present disclosure have the same meanings as commonly understood by those of ordinary skill in the technical field to which the present disclosure belongs.

[19] It should be noted that the terms used here are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to 2 the present disclosure. As used herein, unless the context clearly indicates otherwise, the LUS00846 singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and/or "including" are used in this specification, they indicate the features, steps, operations, devices, components, and/or combinations thereof.

[20] Term explanation

[21] In the present disclosure, "rotation speed" refers to the total number of rotation in the grinding process.

[22] A method for pulping wheat straw using xylanase and pectinase includes the following steps:

[23] (1) Place the naturally air-dried wheat straw and water in a water bath at a ratio of 1:8 for 2h swelling treatment;

[24] (2) Add 1.5% potassium hydroxide (KOH) solution for treatment, and adjust the pH to neutral with phosphoric acid solution after standing for 1 hour;

[25] (3) Under neutral conditions, add a mixture of xylanase and pectinase at an appropriate temperature, the addition amount is 10U/g absolutely dry pulp, and the reaction is 30min;

[26] (4) Grind the processed samples with a grinder, and set the rotation speed to 3000r.

[27] The above is only a preliminary determination of the process route, and the parameters in the process flow can be adjusted appropriately.

[28] In some embodiments, in the swelling treatment, the volume ratio of wheat straw to water is 1:6 to 10, preferably 1:8.

[29] Swelling is an important process of pulping. During the swelling process, the cellulose in the wheat straw and the hydroxyl groups contained in the hemicellulose interact with water molecules. The water molecules enter the amorphous area of the cellulose and form hydrogen bonds with the adsorbed water molecules. The shaping zone is relatively irregular, which is caused by the characteristics of easy adsorption of water molecules. During swelling, the distance between the cellulose molecular chains becomes larger, the specific volume and specific surface area of the cellulose increase, the fiber diameter swells, and the fiber deforms, which is beneficial to subsequent pulping.

[30] In some embodiments, the swelling treatment time is 1 to 3 hours, preferably 2 hours.

[31] In some embodiments, the alkaline solution is potassium hydroxide solution, and preferably, the molar concentration of the potassium hydroxide solution is 1.5%. KOH ionizes in water to form K* and OH. OH" acts on the phenolic structure of the lignin molecule at a higher temperature, causing the ct-aromatic ether bond (X-alkyl bond) to break, and break the P-aromatic ether bond and methyl aryl ether bond in the non-phenolic structure, thereby making the lignin molecule smaller, and introducing hydrophilic groups into the smaller lignin molecule to dissolve the lignin into the slurry, so as to break away from the fiber.

[32] In some embodiments, the treatment time in the alkaline solution is 0.8 to 1.2h, preferably 1h.

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[33] In some embodiments, the total amount of the enzyme in the mixture of LU500846 xylanase and pectinase is 10 U/g of absolute dry pulp, and the ratio of xylanase to pectinase is 1:1 to 2.

[34] In some embodiments, the time of the enzyme treatment is 20 to 40 min, preferably 30 min.

[35] In some embodiments, the number of rotation speed of the grinding is 2500-3000r, preferably 2500r or 2850r.

[36] The present disclosure will be further described in detail below with reference to specific embodiments. It should be pointed out that the specific embodiments are for explaining rather than limiting the present disclosure.

[37] Example 1:

[38] (1) Place the naturally air-dried wheat straw and water in a water bath at a ratio of 1:7 for swelling treatment for 2 hours;

[39] (2) Add 2.0% potassium hydroxide (KOH) solution for treatment, and adjust the pH to neutral with phosphoric acid solution after standing for 1 hour;

[40] (3) Under neutral conditions, add a mixture of xylanase and pectinase at 80 °C, wherein the addition ratio of xylanase and pectinase is 1:1, and the addition amount is 10U/ g absolutely dry pulp, react for 30min;

[41] (4) Grind to process samples with a grinder and set rotation speed to 2500r.

[42] The pulp grinding degree measured after the above steps is 44.33° SR.

[43] Example 2:

[44] (1) Place the natural air-dried wheat straw and water in a water bath at a ratio of 1:7.56 for 2h swelling treatment;

[45] (2) Add 1.75% potassium hydroxide (KOH) solution for treatment, and adjust the pH to neutral with phosphoric acid solution after standing for 1 hour;

[46] (3) Under neutral conditions, add a mixture of xylanase and pectinase at 80 °C, wherein the addition ratio of xylanase and pectinase is 1:1, and the addition amount is 10U/ g absolutely dry pulp, react for 30min;

[47] (4) Grind to process samples with a grinder, and set the rotation speed to 2850r.

[48] The pulp grinding degree measured after the above steps is 43° SR.

[49] Example 3:

[50] Compared with Example 1, under the condition that other factors remain unchanged, adjust t rotation speed and test the relationship between it and the degree of grinding. The results show that when the number of rotation speed reaches 2000-3000r, it can reach 40-45° SR. It is the same as normal demand of the factory.

[S1] Finally, it should be noted that the above descriptions are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Although the present disclosure has been described in detail with reference to the foregoing embodiments, for those skilled in the art. The technical solutions described in the foregoing embodiments may still be modified, or some of them may be equivalently replaced. Any modification, equivalent replacement, improvement, etc.

made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure. Although the foregoing description of the specific implementation of the present disclosure is not a limitation of the protection 4 scope of the present disclosure, those skilled in the art should understand that on the LU500846 basis of the technical solution of the present disclosure, Various modifications or variations made by those skilled in the art without inventive work still fall within the protection scope of the present disclosure.

Claims

WHAT IS CLAIMED IS: LUS00846

1. A method for pulping wheat straw using xylanase and pectinase, wherein it comprises: Swelling treatment of wheat straw; Treating the swelled wheat straw in an alkaline solution, and then adjust pH to neutral; Under neutral conditions, using a mixture of xylanase and pectinase to enzymatically treat and grind slurry after treated with the alkaline solution to obtain.

2. The method for pulping wheat straw using xylanase and pectinase according to claim 1, wherein, in the swelling treatment, a volume ratio of wheat straw to water is 1:6 to 10, preferably 1:8.

3. The method for pulping wheat straw using xylanase and pectinase according to claim 1, wherein the swelling treatment time is 1 to 3 hours, preferably 2 hours.

4. The method for pulping wheat straw using xylanase and pectinase according to claim 1, wherein the alkaline solution is potassium hydroxide solution, preferably, a molar concentration of potassium hydroxide solution is 1.5%.

5. The method for pulping wheat straw using xylanase and pectinase according to claim 1, wherein the treatment time in the alkaline solution is 0.8 to 1.2h, preferably 1h.

6. The method for pulping wheat straw using xylanase and pectinase according to claim 1, wherein a total amount of enzyme in the mixture of xylanase and pectinase is 10U/g absolutely dry pulp, a ratio of xylanase to pectinase is 1:1 to 2.

7. The method for pulping wheat straw using xylanase and pectinase according to claim 1, wherein an enzyme treatment time is 20 to 40 min, preferably 30 min.

8. The method for pulping wheat straw using xylanase and pectinase according to claim 1, wherein a grinding rotation speed is 2500 to 3000r, preferably 2500r or 2850r.

9. Pulp prepared by a method of any one of claims 1 to 8.

10. Application of the mixture of xylanase and pectinase in wheat straw pulping.

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