A biological extraction method for fibers in waste tropical crop raw materials

Abstract

The present invention relates to the technical field of fiber extraction, and specifically discloses a biological extraction method for fibers in waste tropical crop raw materials, comprising the following steps: pretreating the raw materials; pretreating the pretreated raw materials, inoculating with liquid white rot fungus strains to obtain fiber raw materials; loosening the fiber raw materials, washing with clear water, and drying and then loosening them to obtain the product. By pretreating the collected waste tropical crops as raw materials, and then selecting biological enzymes to pretreat the pretreated raw materials, the degumming efficiency of the crops is improved, the fineness and softness of the crop fibers are enhanced. Finally, by inoculating with liquid white rot fungus strains and mixing the strains evenly with the pretreatment product for deep treatment, the degradation degree of lignin and hemicellulose in the crops is increased, which is beneficial to the extraction of crop fibers, realizing the efficient utilization of waste crops.

Description

Technical Field

[0001] The present invention specifically relates to the technical field of fiber extraction, and more specifically, to a biological extraction method for fibers in waste tropical crop raw materials. Background Art

[0002] China is one of the major producers of bananas and pineapples. Each year, tens of millions of tons of banana and pineapple by-products (such as pineapple leaves, banana stalks, etc.) are generated. The vast majority of these by-products are discarded as garbage, seriously polluting the environment. A large amount of cellulose fibers are contained in banana stalk phloem and pineapple leaves. Developing and utilizing them can not only expand the source of natural fibers but also protect the ecological environment.

[0003] The chemical compositions of banana phloem fibers and pineapple leaf fibers are similar to those of other bast fibers. They contain more gum impurities, especially with a relatively high lignin content (4%-13%), which is much higher than that of ramie and flax (1%-3%) and lower than that of jute (10%-15%). Therefore, the softness and spinnability of banana phloem fibers and pineapple leaf fibers are better than those of jute but inferior to those of ramie and flax.

[0004] Taking appropriate degumming treatment before spinning of banana phloem fibers and pineapple leaf fibers can improve the spinnability of the fibers, reduce the residual gum rate of the fibers, and improve the yarn quality. The traditional methods for extracting banana and pineapple fibers mainly include three types: manual method, mechanical method, and chemical method. The manual extraction method has problems such as high labor costs and hard fiber. The mechanical method saves labor, but the fiber strength is relatively low and the damage is large, unable to meet the requirements of spinning. When extracting fibers by the chemical method, after the modified pineapple fibers are processed through deep processing, they are white in appearance, soft and smooth to the touch, and have excellent strength, but the environmental pollution is serious. Therefore, it is very necessary to develop a biological extraction method for banana and pineapple fibers.

[0005] Yan Tingting (2011) disclosed a method using laccase / mediator treatment to solve the problem of high lignin content in jute, resulting in thick and hard fibers. Tian Yinghua et al. used biological enzymes to degrade hemicellulose and lignin in pineapple leaf fiber raw materials to extract fibers. The residual gum rate of the fibers reached below 25.53%, the fiber breaking strength reached above 44.81 CN / tex, and the fineness was above 650 counts [Patent No.: ZL202010749926.6]. Li Longxiang disclosed a banana fiber and banana peel fiber extraction process and equipment, which fully utilized banana peel as a cheap source of fiber raw materials, had a green and environmental protection social effect, and the developed facial mask base cloth was superior to the base cloth products of other plant fibers [Patent No.: ZL201910219336.X]. There has been no report on the combined treatment of bacteria and enzymes to extract pineapple leaf fibers and banana stalk phloem fibers. Summary of the Invention

[0006] The purpose of the present invention is to provide a biological extraction method for fibers in waste tropical crop raw materials to solve the problems raised in the above background art.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A biological extraction method for fibers in waste tropical crop raw materials, comprising the following steps:

[0009] S10. Collect waste tropical crops as raw materials and pretreat the raw materials;

[0010] S20. Select biological enzymes to perform pretreatment on the pretreated raw materials under the condition of a bath ratio of 1:30. Put the pretreatment product into a Mason jar, inoculate with a liquid strain of white rot fungus, shake the waste tropical crop raw materials in the Mason jar to make the strain and the pretreatment product evenly mixed, and put the Mason jar into a constant temperature and humidity incubator for 7 - 15 days to obtain fiber raw materials;

[0011] S30. Loosen the fiber raw materials, wash them with clear water, and obtain the product after drying and loosening.

[0012] As a further scheme of the present invention: In step S10, the method for pretreating the raw materials includes the following steps:

[0013] S11. Weigh a certain amount of waste tropical crops, stir them in 80°C hot water for 1 h, and wash them 4 times with tap water to remove the sundries and dust on the surface of the waste crops;

[0014] S12. Dry the waste crops and cut them into pieces 3 - 5 cm long;

[0015] S13. Add an aqueous sodium hydroxide solution to the cut waste crops, and treat them in a temperature environment of 30 - 90°C for 60 - 120 min. After cooling to room temperature, obtain a solid-liquid mixture;

[0016] S14. Put the obtained solid-liquid mixture into a cold trap and stir it. Stir for 4 h at the solid-liquid critical phase temperature, let it stand to room temperature, then centrifuge to remove the supernatant. Centrifuge and wash it with tap water for multiple times until the supernatant is neutral. Take out the residue and dry it at 60°C to constant weight to obtain the pretreated raw materials.

[0017] As a further scheme of the present invention: In step S13, the mass fraction of the aqueous sodium hydroxide solution is 3 - 5 wt%, and the solid-liquid ratio of the waste crops to the aqueous sodium hydroxide solution is 1:24.

[0018] As a further scheme of the present invention: In step S20, the types of biological enzymes selected include xylanase and pectinase.

[0019] As a further solution of the present invention: in step S20, the temperature for pretreating the raw materials pretreated with biological enzymes is 40 - 50 °C, the time is 2 - 4 h, and the pH value is 7 - 9.

[0020] As a further solution of the present invention: in step S20, the white rot fungus liquid spawn includes Phanerochaete chrysosporium, Trametes versicolor, and Phanerochaete sordida.

[0021] As a further solution of the present invention: when loading the pretreatment product into a Mason jar, deionized water is also added to make the moisture content of the substrate reach 75%. A 0.22 - μm glass fiber membrane is used to replace the cover slip of the separation cover, the separation cover is covered, and the mouth of the Mason jar is wrapped with a stainless - steel cover slip and two layers of newspaper.

[0022] As a further solution of the present invention: after the pretreatment product is loaded into the Mason jar, sterilization treatment is also required. The method of the sterilization treatment is: sterilize in a temperature environment of 121 °C for 30 - 60 min, and after an interval of 12 h, sterilize again in a temperature environment of 121 °C for 30 min.

[0023] As a further solution of the present invention: in step S20, the inoculation amount of the white rot fungus liquid spawn is 5% v / w.

[0024] As a further solution of the present invention: when culturing the Mason jar in a constant - temperature and constant - humidity incubator for 7 - 15 days in step S20, keep the temperature of the constant - temperature and constant - humidity incubator at 28 °C and the humidity at 75%.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention pretreats the collected waste tropical crops as raw materials to destroy the crystallinity of lignocellulose, then selects biological enzymes to pretreat the pretreated raw materials to improve the degumming efficiency of the crops, making the crop fibers have improved fineness and softness. Finally, by inoculating the white rot fungus liquid spawn and mixing the spawn evenly with the pretreatment product for deep treatment, the degradation degree of lignin and hemicellulose in the crops is increased, which is beneficial to the extraction of crop fibers, realizing the efficient utilization of waste crops. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flowchart of the biological extraction method of fibers in waste tropical crop raw materials. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, in conjunction with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] Embodiment 1

[0029] Please refer to Figure 1 , in the embodiment of the present invention, a biological extraction method for fibers in waste tropical crop raw materials includes the following steps:

[0030] S10. Collect waste tropical crops as raw materials and pre-treat the raw materials. It should be noted that the waste tropical crops include pineapple leaves, banana stems, mulberry bark, coconut shells, etc. In this embodiment, pineapple leaves are preferably used. In addition, in step S10, there is also a preliminary treatment step for pineapple leaves, and this step is: cut off the thorns on the edges of the pineapple leaves, and use the method of beating or rolling to crack the pineapple leaves, and mechanically scrape off most of the mesophyll.

[0031] In step S10 of the embodiment of the present invention, the method for pre-treating the raw materials includes the following steps:

[0032] S11. Weigh a certain amount of waste tropical crops, stir them in 80°C hot water for 1 h, and wash them 4 times with tap water to remove the sundries and dust on the surface of the waste crops.

[0033] S12. After drying the waste crops, cut them into pieces 3 - 5 cm long. It should be noted that the purpose of using the physical treatment method is mainly to destroy the crystallinity of lignocellulose. In this embodiment, the physical treatment method also includes steam explosion method, ultrasonic treatment method and microwave treatment method.

[0034] S13. Add sodium hydroxide aqueous solution to the cut waste crops, and treat them in a 30°C temperature environment for 60 min. After cooling to room temperature, a solid-liquid mixture is obtained. It should be noted that when treating crop fibers at low temperature, the hydroxide ions in the alkali solution can expand the swelling between the microfibers of the crops. Under the action of shear external force, it is beneficial to remove hemicellulose and lignin. After treatment, the overall structure of the crop microfibers changes from dense before treatment to loose, and there is dispersion and bending between the microfibers.

[0035] Further, in step S13 of the embodiment of the present invention, the mass fraction of the sodium hydroxide aqueous solution is 3 wt%, and the solid-liquid ratio of the waste crops to the sodium hydroxide aqueous solution is 1:24.

[0036] S14. Put the obtained solid-liquid mixture into a cold trap and stir it for 4 h at the solid-liquid critical phase temperature. After standing to room temperature, centrifuge and remove the supernatant. Centrifuge and wash it with tap water multiple times until the supernatant is neutral. Take out the residue and dry it at 60 °C to constant weight to obtain the pretreated raw material.

[0037] S20. Under the condition of a bath ratio of 1:30, select a biological enzyme to pretreat the pretreated raw material. Put the pretreatment product into a Mason jar, inoculate the liquid strain of white rot fungus, and shake the waste tropical crop raw material in the Mason jar to make the strain and the pretreatment product evenly mixed. Put the Mason jar into a constant temperature and humidity incubator and culture it for 7 days, keeping the temperature of the constant temperature and humidity incubator at 28 °C and the humidity at 75%.

[0038] It should be noted that after adding the liquid strain of white rot fungus to treat the crops, the degradation degree of lignin and hemicellulose in the crops is improved, which is beneficial to the extraction of crop fibers to obtain fiber raw materials. It should be noted that using biological enzymes (xylanase, pectinase) to pretreat the crops can improve the degumming efficiency of the crops, not only reduce environmental pollution, but also effectively improve the properties such as the fineness and flexibility of the fibers, making the crop fibers have improved fineness and softness, thus being beneficial to the extraction of crop fibers.

[0039] In step S20 of the embodiment of the present invention, the types of biological enzymes selected include xylanase and pectinase; further, in this embodiment, the temperature for pretreating the pretreated raw material with the selected biological enzyme is 40 °C, the time is 2 h, and the pH value is 7.

[0040] In step S20 of the embodiment of the present invention, the liquid strain of white rot fungus includes Trametes gallica, Trametes versicolor, and Phanerochaete chrysosporium. Further, the inoculation amount of the liquid strain of white rot fungus is 5% v / w.

[0041] In step S20 of the embodiment of the present invention, when loading the pretreatment product into the Mason jar, deionized water is also added to make the moisture content of the matrix reach 75%. Replace the separation cover slide with a 0.22 μm glass fiber membrane, cover the separation cover, and wrap the mouth of the Mason jar with a stainless steel cover slide and two layers of newspaper. After loading the pretreatment product into the Mason jar, sterilization treatment is also required. The method of the sterilization treatment is: sterilize in a temperature environment of 121 °C for 30 min. After an interval of 12 h, sterilize again in a temperature environment of 121 °C for 30 min.

[0042] S30. Loosen the fiber raw material and wash it with clear water. After drying, loosen it to obtain the fiber extracted from the waste tropical crop raw material.

[0043] Example 2

[0044] Please refer to Figure 1, in the embodiments of the present invention, a method for biologically extracting fibers from waste tropical crop raw materials includes the following steps:

[0045] S10. Collect waste tropical crops as raw materials and pre-treat the raw materials. It should be noted that the waste tropical crops include pineapple leaves, banana stalks, mulberry bark, coconut shells, etc. In this embodiment, pineapple leaves are preferably used. Additionally, in step S10, there is also a preliminary treatment step for pineapple leaves, which is: cut off the thorns on the edges of the pineapple leaves, use the method of knocking or rolling to crack the pineapple leaves, and mechanically scrape off most of the mesophyll;

[0046] In step S10 of the embodiments of the present invention, the method for pre-treating the raw materials includes the following steps:

[0047] S11. Weigh a certain amount of waste tropical crops, stir them in hot water at 80 °C for 1 h, and wash them 4 times with tap water to remove the sundries and dust on the surface of the waste crops;

[0048] S12. Dry the waste crops and cut them into lengths of 3 - 5 cm. It should be noted that the purpose of using the physical treatment method is mainly to destroy the crystallinity of lignocellulose. In this embodiment, the physical treatment method also includes steam explosion method, ultrasonic treatment method, and microwave treatment method;

[0049] S13. Add an aqueous sodium hydroxide solution to the cut waste crops, and treat them in a temperature environment of 90 °C for 120 min. After cooling to room temperature, a solid-liquid mixture is obtained. It should be noted that when treating crop fibers at low temperature, the hydroxide ions in the alkali solution can expand the swelling between the microfibers of the crops. Under the action of shear external force, it is beneficial to remove hemicellulose and lignin. After treatment, the overall structure of the crop microfibers changes from being dense before treatment to being loose, and dispersion and bending occur between the microfibers;

[0050] Furthermore, in step S13 of the embodiments of the present invention, the mass fraction of the aqueous sodium hydroxide solution is 5 wt%, and the solid-liquid ratio of the waste crops to the aqueous sodium hydroxide solution is 1:24;

[0051] S14. Put the above-obtained solid-liquid mixture into a cold trap and stir it. Stir it for 4 h at the solid-liquid critical phase temperature. After standing to room temperature, centrifuge to remove the supernatant. Centrifuge and wash it with tap water multiple times until the supernatant is neutral. Take out the residue and dry it at 60 °C to constant weight, and thus obtain the pre-treated raw materials.

[0052] S20. Under the condition of a liquor ratio of 1:30, select biological enzymes to pretreat the pretreated raw materials, put the pretreatment products into Mason bottles, inoculate with liquid white-rot fungus strains, shake the waste tropical crop raw materials in the Mason bottles to make the strains and pretreatment products mix evenly, and put the Mason bottles into a constant temperature and humidity incubator for 15 days. It should be noted that when the Mason bottles are placed in the constant temperature and humidity incubator for 15 days, keep the temperature of the constant temperature and humidity incubator at 28 °C and the humidity at 75%. It should be noted that after adding the liquid white-rot fungus strains to treat the crops, the degradation degree of lignin and hemicellulose in the crops is improved, which is beneficial to the extraction of crop fibers;

[0053] It should be noted that using biological enzymes (xylanase, pectinase) to pretreat crops can improve the degumming efficiency of crops, not only reduce environmental pollution, but also effectively improve the properties such as the fineness and spinnability of fibers, making the crop fibers have improved fineness and softness, thus being beneficial to the extraction of crop fibers;

[0054] In step S20 of the embodiment of the present invention, the types of biological enzymes selected include xylanase and pectinase; further, in this embodiment, the temperature for pretreating the pretreated raw materials with the selected biological enzymes is 50 °C, the time is 4 h, and the pH value is 9.

[0055] In step S20 of the embodiment of the present invention, the liquid white-rot fungus strains include Trametes gallica, Trametes versicolor, and Phanerochaete chrysosporium. Further, the inoculation amount of the liquid white-rot fungus strains is 5% v / w.

[0056] In step S20 of the embodiment of the present invention, when the pretreatment products are put into Mason bottles, deionized water is also added to make the moisture content of the matrix reach 75%. Replace the separation cover slip with a 0.22 μm glass fiber membrane, cover the separation cover, wrap the mouth of the Mason bottle with a stainless steel cover slip and two layers of newspaper. After the pretreatment products are put into the Mason bottles, sterilization treatment is also required. The method of the sterilization treatment is: sterilize in a temperature environment of 121 °C for 60 min, and after an interval of 12 h, sterilize again in a temperature environment of 121 °C for 30 min.

[0057] S30. Loosen the fiber raw materials and wash them with clean water, and then loosen them after drying to obtain the fibers extracted from the waste tropical crop raw materials.

[0058] Example 3

[0059] Please refer to Figure 1 , in the embodiment of the present invention, a method for biologically extracting fibers from waste tropical crop raw materials includes the following steps:

[0060] S10. Collect waste tropical crops as raw materials and pre-treat the raw materials. It should be noted that the waste tropical crops include pineapple leaves, banana stalks, mulberry bark, coconut shells, etc. In this embodiment, pineapple leaves are preferably used. In addition, in step S10, there is also a preliminary treatment step for pineapple leaves, and this step is: cut off the thorns on the edge of the pineapple leaves, use the method of knocking or rolling to crack the pineapple leaves, and mechanically scrape off most of the mesophyll;

[0061] In step S10 of the embodiment of the present invention, the method for pre-treating the raw materials includes the following steps:

[0062] S11. Weigh a certain amount of waste tropical crops, stir them in 80°C hot water for 1 h, and wash them 4 times with tap water to remove the sundries and dust on the surface of the waste crops;

[0063] S12. Dry the waste crops and cut them into pieces 3 - 5 cm long. It should be noted that the purpose of using the physical treatment method is mainly to destroy the crystallinity of lignocellulose. In this embodiment, the physical treatment method also includes steam explosion method, ultrasonic treatment method and microwave treatment method;

[0064] S13. Add sodium hydroxide aqueous solution to the cut waste crops, and treat them in a 60°C temperature environment for 90 min. After cooling to room temperature, a solid-liquid mixture is obtained. It should be noted that when treating crop fibers at low temperature, the hydroxide ions in the alkali solution can expand the swelling between the microfibers of the crops. Under the action of shear external force, it is beneficial to remove hemicellulose and lignin. After treatment, the overall structure of the crop microfibers changes from dense before treatment to loose, and dispersion and bending appear between the microfibers;

[0065] Furthermore, in step S13 of the embodiment of the present invention, the mass fraction of the sodium hydroxide aqueous solution is 4 wt%, and the solid-liquid ratio of the waste crops to the sodium hydroxide aqueous solution is 1:24;

[0066] S14. Put the above-obtained solid-liquid mixture into a cold trap and stir it. Stir it for 4 h at the solid-liquid critical phase temperature. After standing to room temperature, centrifuge to remove the supernatant. Centrifuge and wash it with tap water multiple times until the supernatant is neutral. Take out the residue and dry it at 60°C to constant weight, and then the pre-treated raw materials are obtained.

[0067] S20. Under the condition of a liquor ratio of 1:30, select bioenzymes to pretreat the pretreated raw materials. Put the pretreatment products into Mason bottles, inoculate with liquid white-rot fungus strains, shake the waste tropical crop raw materials in the Mason bottles to make the strains and the pretreatment products evenly mixed. Put the Mason bottles into a constant temperature and humidity incubator for 10 days. It should be noted that when the Mason bottles are placed in the constant temperature and humidity incubator for 10 days, keep the temperature of the constant temperature and humidity incubator at 28 °C and the humidity at 75%. It should be noted that after adding the liquid white-rot fungus strains to treat the crops, the degradation degree of lignin and hemicellulose in the crops is improved, which is beneficial to the extraction of crop fibers;

[0068] It should be noted that using bioenzymes (xylanase, pectinase) to pretreat crops can improve the degumming efficiency of crops, not only reduce environmental pollution, but also effectively improve the properties such as the fineness and flexibility of fibers, making the crop fibers have improved fineness and softness, thus being beneficial to the extraction of crop fibers;

[0069] In step S20 of the embodiment of the present invention, the types of bioenzymes selected include xylanase and pectinase; further, in this embodiment, the temperature for selecting bioenzymes to pretreat the pretreated raw materials is 45 °C, the time is 3 h, and the pH value is 8.

[0070] In step S20 of the embodiment of the present invention, the liquid white-rot fungus strains include Trametes gallica, Trametes versicolor and Phanerochaete chrysosporium. Further, the inoculation amount of the liquid white-rot fungus strains is 5% v / w.

[0071] In step S20 of the embodiment of the present invention, when the pretreatment products are put into Mason bottles, deionized water is also added to make the moisture content of the matrix reach 75%. Replace the separation cover slide with a 0.22 μm glass fiber membrane, cover the separation cover, wrap the mouth of the Mason bottle with a stainless steel cover slide and two layers of newspaper. After the pretreatment products are put into the Mason bottles, sterilization treatment is also required. The method of the sterilization treatment is: sterilize in a temperature environment of 121 °C for 45 min, and after an interval of 12 h, sterilize again in a temperature environment of 121 °C for 30 min.

[0072] S30. Loosen the fiber raw materials and wash them with clear water, and then loosen them after drying to obtain the fibers extracted from the waste tropical crop raw materials.

[0073] In summary, the present invention pre-treats the collected waste tropical crops as raw materials to destroy the crystallinity of lignocellulose, then selects biological enzymes to pre-treat the pre-treated raw materials to improve the degumming efficiency of the crops, making the crop fibers finer and softer. Finally, by inoculating the liquid strain of white-rot fungi and mixing the strain evenly with the pre-treatment product for deep treatment, the degradation degree of lignin and hemicellulose in the crops is increased, which is beneficial to the extraction of crop fibers, realizing the efficient utilization of waste crops.

[0074] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be construed as limiting the claimed invention.

[0075] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A biological extraction method for fibers in waste tropical crop raw materials, characterized in that, It includes the following steps: S10. Collect waste tropical crops as raw materials and pretreat the raw materials; S20. Select biological enzymes to pretreat the pretreated raw materials under the condition of a bath ratio of 1:

30. Put the pretreated product into a Mason jar, inoculate with a liquid strain of white-rot fungi, shake the waste tropical crop raw materials in the Mason jar to make the strain and the pretreated product evenly mixed, and put the Mason jar into a constant temperature and humidity incubator for 7 - 15 days to obtain fiber raw materials; In step S20, when the pretreated product is put into the Mason jar, deionized water is also added to make the moisture content of the substrate reach 75%. Replace the separation cover glass with a 0.22μm glass fiber membrane, cover the separation cover, and wrap the mouth of the Mason jar with a stainless steel cover glass and two layers of newspaper. After the pretreated product is put into the Mason jar, sterilization treatment is also required. The method of the sterilization treatment is: sterilize in a temperature environment of 121°C for 30 - 60 min, and after an interval of 12 h, sterilize again in a temperature environment of 121°C for 30 min; S30. Wash the fiber raw materials with clear water, dry them and then loosen them to obtain the product; Among them, in step S10, the method for pretreating the raw materials includes the following steps: S11. Weigh a certain amount of waste tropical crops, stir them in 80°C hot water for 1 h, and wash them 4 times with tap water to remove the sundries and dust on the surface of the waste crops; S12. Dry the waste crops and then cut them into sections, 3 - 5 cm long; S13. Add an aqueous sodium hydroxide solution to the cut waste crops, and treat them in a temperature environment of 30 - 90°C for 60 - 120 min. After cooling to room temperature, a solid-liquid mixture is obtained; S14. Put the solid-liquid mixture obtained in step S13 into a cold trap and stir it. Stir for 4 h at the solid-liquid critical phase temperature. After standing to room temperature, centrifuge to remove the supernatant. Centrifuge and wash it with tap water multiple times until the supernatant is neutral. Take out the residue and dry it at 60°C to constant weight to obtain the pretreated raw materials.

2. The method for biological extraction of fibers from waste tropical crop raw materials according to claim 1, characterized in that, In step S13, the mass fraction of the aqueous sodium hydroxide solution is 3 - 5 wt%, and the solid-liquid ratio of the waste crops to the aqueous sodium hydroxide solution is 1:

24.

3. The biological extraction method of fibers from waste tropical crop raw materials according to claim 1, characterized in that, In step S20, the types of the biological enzymes include xylanase and pectinase.

4. The method for biological extraction of fibers from waste tropical crop raw materials according to claim 3, characterized in that In step S20, the temperature for selecting biological enzymes to pretreat the pretreated raw materials is 40 - 50°C, the time is 2 - 4 h, and the pH value is 7 - 9.

5. The biological extraction method of fibers from waste tropical crop raw materials according to claim 1, characterized in that, In step S20, the liquid strain of white-rot fungi includes Trametes gallica, Trametes versicolor and Phanerochaete chrysosporium.

6. The method for biological extraction of fibers from waste tropical crop raw materials according to claim 5, characterized in that, In step S20, the inoculation amount of the liquid strain of white-rot fungi is 5% v / w.

7. The method for biological extraction of fibers from waste tropical crop raw materials according to claim 1, characterized in that, In step S20, when the Mason jar is put into the constant temperature and humidity incubator for 7 - 15 days, keep the temperature of the constant temperature and humidity incubator at 28°C and the humidity at 75%.

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