A method for preparing high-yield bamboo pulp using white rot fungi

Abstract

The present application provides a method for preparing high-yield bamboo pulp using white rot fungi, which belongs to the field of papermaking technology and includes the following steps: hydrothermally pretreating bamboo chips; subjecting the hydrothermally pretreated bamboo chips to pulping treatment to obtain extruded pulp; sterilizing the extruded pulp to obtain sterilized pulp; inoculating the sterilized pulp with white rot fungi that have been subjected to ARTP mutagenesis treatment, and subjecting the sterilized pulp to microbial culture treatment to obtain microbial treated pulp; subjecting the microbial treated pulp to pulping treatment to obtain bamboo pulp. No chemicals are added during the pulping process of the present application method, pulping wastewater is easier to degrade, and energy consumption is lower. After the bamboo pulp obtained is sheeted into paper, the paper has high density, bursting index, tensile strength, and tear index, and the paper exhibits excellent physical properties.

Description

Technical Field

[0001] The present application belongs to the technical field of papermaking, and more specifically, relates to a method for preparing high-yield bamboo pulp by utilizing white rot fungi. Background Art

[0002] China's forest resources are relatively scarce, with per capita forest area less than 1 / 4 of the world's average. However, China has rich bamboo resources, with more than 500 species of bamboo plants. According to the "2021 China Forest and Grassland Ecological Comprehensive Monitoring and Evaluation Report" released by the State Forestry and Grassland Administration, the bamboo forest area in my country in 2021 was 7.5627 million hm2. 2 , accounting for 3.31% of the forest area. The rational, efficient and green use of bamboo will effectively alleviate the current shortage of forest resources in China. Bamboo has a high cellulose content, slender fiber shape, good mechanical properties and plasticity. As a good alternative material for wood papermaking raw materials, bamboo can meet the pulp requirements for making medium and high-end paper. Studies have shown that bamboo chemical composition and fiber properties have good pulping properties. The performance of bamboo pulp is second only to coniferous wood pulp, and is better than broad-leaved wood pulp and grass pulp. Vigorously developing the bamboo pulping and papermaking industry is of great significance to alleviating the current shortage of wood pulp raw materials. Compared with bamboo chemical pulp, bamboo high-yield pulp has the advantages of high yield, low investment, low chemical consumption, and low pollution load.

[0003] At present, most bio-pulping uses microorganisms to coordinate chemical treatment for pulping. For example, Chinese patent CN 115029947A discloses a method for preparing APMP pulp by twin screw extruders using microorganisms for pretreatment. In this patent, 6% sodium hydroxide alkali solution is used to soak wood chips for 8 hours at a temperature of 45°C using alkaline water with a material-liquid ratio of 1:4. The wood chips after impregnation are then extruded and rolled using a twin screw extruder. The amount of chemicals used in the early impregnation process is very large. Patent CN115637600A discloses a method for preparing bamboo pulp using a composite bacterial agent. In this patent, chemicals such as hydrogen peroxide, sodium silicate, caustic soda and DTPA are also added. Patent CN 114775317A discloses a method for preparing paper pulp by pretreating wood chips using vermilion pycnopsis. This patent uses 6% sodium hydroxide alkali solution and cooks for 30 minutes at a temperature of 130°C and a material-liquid ratio of 1:4. There are still problems of large alkali usage and high pulping energy consumption. Summary of the invention

[0004] The purpose of the present application is to provide a method for preparing high-yield bamboo pulp using white rot fungi. No chemicals are added during the pulping process, pulping wastewater is easier to degrade, energy consumption is low, and the physical properties of the paper after white rot fungi treatment are excellent.

[0005] To achieve the above object, the present application provides a method for preparing high-yield bamboo pulp using white rot fungi, comprising the following steps:

[0006] The bamboo chips are subjected to hydrothermal pretreatment;

[0007] The hydrothermally pretreated bamboo chips are subjected to pulping treatment to obtain extruded pulp;

[0008] Sterilizing the extruded slurry to obtain a sterilized slurry;

[0009] Inoculating the sterilized slurry with white rot fungi that have been subjected to ARTP mutation treatment, and performing microbial culture treatment to obtain a slurry treated with microorganisms;

[0010] The pulp treated with the microorganisms is subjected to pulping treatment to obtain bamboo pulp.

[0011] Furthermore, the conditions of the ARTP mutagenesis treatment are: mutagenesis temperature 25-35° C., mutagenesis time 80-120 s, helium flow rate 5-15 SLM.

[0012] Furthermore, the temperature of the hydrothermal pretreatment is 80-100° C., and the time is 1-3 hours.

[0013] Furthermore, during the hydrothermal pretreatment process, the solid-liquid ratio is 1:2 to 1:6.

[0014] Furthermore, the slurry extrusion treatment is carried out in a single-screw extrusion decomposition machine, the extrusion diameter of the single-screw extrusion decomposition machine is 80-100 mm, the compression ratio is 3:1-4:1, the rotation speed is 30-40 r / min, and the number of extrusions is 2 times.

[0015] Furthermore, the sterilization treatment is carried out in a high pressure sterilizer, the sterilization pressure is 0.1-0.14 MPa, the sterilization temperature is 120-130° C., and the sterilization time is 20-40 min.

[0016] Furthermore, the inoculation amount of the white rot fungus after the ARTP mutagenesis treatment in the sterilized slurry is: based on the absolute dry slurry, the number of white rot fungus spores added per 100g of absolute dry slurry is 2×10 8 ~3×10 8 indivual.

[0017] Furthermore, the conditions for the microorganism culture treatment are: the culture temperature is 28-32° C., the culture humidity is 65-85% RH, and the culture time is 28-35 days.

[0018] Furthermore, the number of refining stages in the refining treatment is 2 stages, the gap between the grinding discs in the first stage is 0.4-0.2 mm, the gap between the grinding discs in the second stage is 0.2-0.1 mm, and the refining concentration is 20%-30%.

[0019] Furthermore, the method also includes the steps of screening, concentrating and sheeting the bamboo pulp.

[0020] Compared with the prior art, this application has the following technical effects:

[0021] The present application discloses a method for preparing high-yield bamboo pulp using white rot fungi. The bamboo pieces are first subjected to hydrothermal pretreatment, and then subjected to pulping treatment. After the hydrothermal pretreatment, the bamboo pieces can be fully moistened, so that the extruded bamboo fibers are more dispersed and loose, which is conducive to the subsequent fuller contact between the white rot fungi hyphae and the bamboo fibers and improves the efficiency of microbial pulping. In addition, the present application uses white rot fungi that have been subjected to ARTP mutagenesis treatment to perform microbial culture treatment on the sterilized pulp. Under the action of the white rot fungi, cavities and grooves appear in the bamboo material, the pore size and specific surface area increase, and the hemicellulose and lignin in the bamboo material are partially degraded. At the same time, the relaxation of the fiber cell wall produced is also conducive to the separation of fibers during pulping and the development of fine fibers, which saves energy consumption and helps to interweave and combine fibers when forming paper sheets. No chemicals are added in the pulping process of the present application, pulping wastewater is easier to degrade, and energy consumption is lower. On the other hand, the present application uses white rot fungi that have been subjected to ARTP mutagenesis treatment to treat bamboo pulp, and screens out strains with strong hemicellulose degradation ability and weak lignin degradation ability through ARTP mutagenesis. The hemicellulose degradation rate of the bamboo pulp treated with this strain is higher than that of the bamboo pulp treated with white rot fungi that have not been subjected to ARTP mutagenesis. Under the same treatment conditions, the physical properties of the bamboo pulp treated with white rot fungi after ARTP mutagenesis are better than the physical properties of the bamboo pulp directly treated with conventional white rot fungi and the bamboo pulp without any fungus treatment.

[0022] The bamboo pulp obtained by the method of preparing high-yield bamboo pulp using white rot fungi in the present application is sheeted into paper. The paper has high density, bursting index, tensile strength and tear index, and the paper exhibits excellent physical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 A flow chart of a method for preparing high-yield bamboo pulp using white rot fungi provided in an embodiment of the present application;

[0025] Figure 2 This is a diagram showing the growth status of white rot fungi on bamboo chips after inoculation and mutagenesis treatment provided in Example 1 of the present application. DETAILED DESCRIPTION

[0026] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0027] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0028] The weight of the relevant components mentioned in the specification of the examples of this application can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the specification of the examples of this application, it is within the scope disclosed in the specification of the examples of this application. Specifically, the mass described in the specification of the examples of this application can be a mass unit known in the biochemical field such as μg, mg, g, kg, etc.

[0029] The present application provides a method for preparing high-yield bamboo pulp using white rot fungi. The preparation process is as follows: Figure 1 As shown, the following steps are included:

[0030] (1) The bamboo pieces are subjected to hydrothermal pretreatment at a temperature of 80 to 100°C for 1 to 3 hours; during the hydrothermal pretreatment, the solid-liquid ratio can be controlled to be 1:2 to 1:6. In addition, the length of the bamboo pieces is 18 to 35 mm and the width is 10 to 20 mm. The bamboo pieces are dust-removed before the hydrothermal pretreatment.

[0031] (2) subjecting the hydrothermally pretreated bamboo chips to pulping treatment to obtain extruded pulp; specifically, the pulping treatment process can be carried out in a single-screw extrusion deflaking machine, the extrusion diameter of the single-screw extrusion deflaking machine is 80 to 100 mm, the compression ratio is 3:1 to 4:1, the rotation speed is 30 to 40 r / min, and the number of extrusions is 2 times.

[0032] (3) sterilizing the extruded slurry to obtain a sterilized slurry; specifically, the sterilization can be performed in a high pressure sterilizer, the sterilization pressure is 0.1-0.14 MPa, the sterilization temperature is 120-130° C., and the sterilization time is 20-40 min. Preferably, the sterilization temperature is 121° C. and the sterilization time is 20 min.

[0033] (4) Inoculating the sterilized slurry with white rot fungi after ARTP mutagenesis treatment and performing microbial culture treatment to obtain a slurry after microbial treatment; specifically, the conditions for ARTP mutagenesis treatment are: mutagenesis temperature 25-35°C, mutagenesis time 80-120s, helium flow rate 5-15SLM. The inoculation amount of the white rot fungi after ARTP mutagenesis treatment in the sterilized slurry is: based on the absolute dry slurry, the number of white rot fungi spores added per 100g of absolute dry slurry is 2×10 8 ~3×10 8 The conditions for the microbial culture treatment are: the culture temperature is 28-32°C, the culture humidity is 65-85%RH, and the culture time is 28-35 days.

[0034] (5) washing the pulp after microbial treatment and then refining it to obtain bamboo pulp. Specifically, the pulping process has two refining stages, the first stage has a grinding disc gap of 0.4-0.2 mm, the second stage has a grinding disc gap of 0.2-0.1 mm, and the refining concentration is 20%-30%.

[0035] Furthermore, the embodiment of the present application also includes the steps of screening, concentrating and sheeting the prepared bamboo pulp, using a pulp screening machine to screen the pulp after the second high-concentration refining, and then concentrating it. After measuring the moisture content in the pulp, a certain amount of pulp is weighed and dispersed by a deflaker, and then sheeted and dried by a sheeting machine. The sheet basis weight is 60g / m 2 .

[0036] In the above step (4), ARTP mutagenesis is atmospheric pressure room temperature plasma mutagenesis. The present application example uses the atmospheric pressure room temperature plasma mutagenesis equipment of Beijing Siqingyuan Biotechnology Co., Ltd. to carry out the mutagenesis treatment of white rot fungi. The specification of the mutagenesis equipment is ADHOC, the model is ARTP-Ⅱ, and high purity helium (99.999%) is used as the working gas. The present application example uses Phanerochaete chrysosporium as a white rot fungus for illustration, and other types of white rot fungi can also play a similar role.

[0037] During the ARTP mutagenesis process, the mutagenesis temperature, mutagenesis time and helium flow rate are all adjustable. Before the ARTP mutagenesis experiment, the helium bottle and the chiller are turned on, and the sterile operating room and the internal operating space of the instrument are ultraviolet sterilized for 30 minutes to ensure that the environment is sterile. In the specific implementation of this application, the mutagenesis temperature is set to 30°C and the helium flow rate is fixed to 10SLM. By adjusting the mutagenesis time, different degrees of damage are caused to the spores of the chrysosporium original hairy leather fungus to obtain different lethality rates. The chrysosporium original hairy leather fungus after mutagenesis is placed in a hemicellulose liquid culture medium in the dark for a period of time, and the cultured bacterial suspension is respectively coated on a hemicellulose-guaiacol solid culture medium and a hemicellulose-aniline blue solid culture medium, and placed in a 30°C incubator for culture. The laccase produced by white rot fungi will react with guaiacol to develop a color, and the peroxide-type enzyme produced will react with aniline blue to produce a fading reaction. Strains with small or no color change and fading circles are the target strains to be screened out. Based on this, strains with strong hemicellulose degradation ability and weak lignin degradation ability are screened out as target strains for subsequent biopulping.

[0038] A method for preparing high-yield bamboo pulp using white rot fungi according to an embodiment of the present application is illustrated below through a plurality of specific embodiments.

[0039] Example 1

[0040] Example 1 of the present application provides a method for preparing high-yield bamboo pulp using white rot fungi, comprising the following steps:

[0041] (1) After the bamboo chips are dusted, they are pre-impregnated with water at 100°C for 1 hour, and the material-liquid ratio of bamboo chips to water is 1:3. The bamboo chips after the hydrothermal impregnation treatment are extruded and rolled with a single-screw extruder. The extrusion diameter of the extruder is 90 mm, the compression ratio is 4:1, and the speed is 38 r / min. The extruded slurry is sterilized in a high-pressure sterilizer at 121°C for 20 minutes for use.

[0042] (2) In a solid culture medium (1 L of potato cooking liquid, 20 g glucose, 3 g KH 2 PO 4 、1.5 g MgSO 4 7H 2 The mature spores of Phanerochaete chrysosporium grown on the slant (0.05 g, 0.005 g vitamin B1, 20 g agar) were washed off the slant, placed in a triangular shake flask filled with glass beads and shaken to release the spores, and the mycelium was filtered through three layers of lens paper to obtain a spore suspension. 1 mL of the spore suspension was centrifuged at 6000 rpm for 6 min, and washed three times with water. The spore concentration was 10 7About 100 μL of the spore suspension prepared in advance is placed on the slide, and at the same time, a corresponding 1.5 mL EP tube (plastic centrifuge tube) containing 1 mL of sterile water is prepared to hold the treated slide.

[0043] ARTP mutagenesis of white rot fungi: Before the ARTP mutagenesis experiment, open the helium bottle and the chiller, and sterilize the sterile operating room and the internal operating space of the instrument with ultraviolet for 30 minutes to ensure that the environment is sterile. Place the slide containing the spore suspension into the mutagenesis platform of the instrument for mutagenesis treatment. The treatment temperature is 30°C, the helium flow rate is 10SLM, and the treatment time is 80s, 90s, 100s, 110s, and 120s respectively. After the mutagenesis treatment, fully shake the EP tube containing the slide for 1 minute to ensure that the spores on the slide are completely washed off. Pipette 1mL of the induced spore suspension into 100mL of hemicellulose liquid culture medium and culture it in the dark at 160rpm and 30°C for 48h. The composition of the hemicellulose liquid culture medium is: liquid fermentation medium (NaCl 0.05g, MgSO 4 0.05 g, (NH 4 ) 2 SO 4 0.3g, KH 2 PO 4 0.1g, CaCl 2 0.03g, 100mL of distilled water, and 1mL of trace element mixture) were added with 5% xylo-oligosaccharide. The trace element mixture contained FeSO 4 7H 2 O 0.0005g, MnSO 4 7H 2 O0.0016g, ZnSO 4 7H 2 O 0.0014g, CoCl 20.002g. After the culture is completed, 90μL of the bacterial suspension in the shake flask is respectively applied to the hemicellulose-guaiacol solid medium and the hemicellulose-aniline blue solid medium, and placed in a 30°C incubator for culture. The composition of the hemicellulose-guaiacol solid medium is as follows: 0.1% guaiacol is added to the hemicellulose solid medium (5% xylo-oligosaccharides and 2% agar are added to the liquid fermentation medium). The composition of the hemicellulose-aniline blue solid medium is as follows: 0.1g / L aniline blue is added to the hemicellulose solid medium. The laccase produced by white rot fungi will react with guaiacol to develop a color, and the peroxide-type enzyme produced will produce a fading reaction with aniline blue. According to the color development reaction and the fading reaction, strains with strong hemicellulose degradation ability and weak lignin degradation ability are selected as the target strains for subsequent biopulping. The screening results of white rot fungi obtained at different mutagenesis treatment times are shown in Table 1 below:

[0044] Table 1

[0045]

[0046] Note: “—” means no color change.

[0047] According to Table 1, strains with larger growth (i.e., larger diameter of hyphae), smaller or no color change and fading circles were selected as target strains for subsequent pulping. Small color change circles represent low laccase activity, and small fading circles represent low peroxidase activity. Laccase and peroxidase are enzymes that degrade lignin. Low activity of these two enzymes represents weak ability to degrade lignin; and the larger the hyphae circle, the better the growth of the fungus, and thus the stronger ability to degrade hemicellulose. Thus, strain No. 3 was selected as the optimal strain (it does not produce a color change circle, and the width of the fading circle is only 3.2-3.0=0.2cm), which is a strain with strong hemicellulose degradation ability and weak lignin degradation ability, and strain No. 3 was used for subsequent biopulping. That is, when the mutagenesis temperature is 30°C and the helium flow rate is 10SLM, the best target strain can be obtained when the mutagenesis time is controlled to 100s.

[0048] (3) The sterilized slurry of step (1) is inoculated with the No. 3 white rot fungus screened in step (2) for treatment. The bacterial treatment step is as follows: the sterilized slurry is cooled under the irradiation of an ultraviolet lamp on a workbench, and after it is completely cooled, a spore suspension of the cultured mutagenic white rot fungus is added, and a liquid fermentation medium (the composition of the liquid fermentation medium is: 0.05 g NaCl, MgSO 4 0.05 g, (NH 4 ) 2 SO 4 0.3g, KH 2 PO 4 0.1g, CaCl 20.03g, distilled water 100mL, trace element mixture 1mL (each 10mL of trace element mixture contains FeSO 4 7H 2 O 0.0005g, MnSO 4 7H 2 O 0.0016g, ZnSO 4 7H 2 O 0.0014g, CoCl 2 0.002 g), 1 mL of trace element mixture was added to every 100 mL of liquid matrix), and the mixture was placed in a biochemical incubator for culture. The inoculation amount of the white rot fungus after ARTP mutagenesis treatment in the sterilized slurry was: based on the absolute dry slurry, the number of white rot fungus spores added per 100 g of absolute dry slurry was 2×10 8 The culture temperature was 30°C, the culture humidity was 75% RH, and the culture time was 28 days.

[0049] The preparation steps of the spore suspension of the induced white rot fungus are as follows: inoculate the induced white rot fungus into a solid culture medium (1L potato cooking liquid, 20g glucose, 3g KH 2 PO 4 、1.5 g MgSO 4 7H 2 The cultured spores were washed off the slant with sterile water, placed in a triangular shake bottle filled with glass beads and shaken to release the spores. The mycelium was filtered with three layers of lens paper to obtain a spore suspension with a spore concentration of 10 8 About pcs / mL.

[0050] (4) After washing the pulp treated with white rot fungi, the pulp was refined at a pulp concentration of 25%, with the gap between the first-stage milling discs being 0.4 mm and the gap between the second-stage milling discs being 0.2 mm.

[0051] (5) The pulp after the second high-concentration refining is screened by a pulp screener, and then concentrated. After the water content in the pulp is measured, a certain amount of pulp is weighed and dispersed by a deflaker, and a sheet making machine is used to make sheets and dry them. The quantitative weight of the sheet is 60g / m 2 .

[0052] Example 2

[0053] Example 2 of the present application provides a method for preparing high-yield bamboo pulp using white rot fungi, comprising the following steps:

[0054] (1) After the bamboo chips are dusted, they are pre-impregnated with water at 100°C for 1 hour, and the material-liquid ratio of bamboo chips to water is 1:4. The bamboo chips after the hydrothermal impregnation treatment are extruded and rolled with a single-screw extruder. The extrusion diameter of the extruder is 90 mm, the compression ratio is 4:1, and the speed is 38 r / min. The extruded slurry is placed in a high-pressure sterilizer for sterilization at 121°C for 20 minutes for use.

[0055] (2) The sterilized slurry in step (1) was inoculated with the No. 3 white rot fungus selected in Example 1 for treatment. The bacterial treatment step was as follows: the sterilized slurry was cooled under the irradiation of an ultraviolet lamp on a workbench, and after it was completely cooled, a spore suspension of the cultured white rot fungus after mutagenesis was added, and a liquid fermentation medium (the composition of the liquid fermentation medium was: 0.05 g NaCl, MgSO 4 0.05 g, (NH 4 ) 2 SO 4 0.3g, KH 2 PO 4 0.1g, CaCl 2 0.03g, distilled water 100mL, trace element mixture 1mL (each 10mL of trace element mixture contains FeSO 4 7H 2 O 0.0005g, MnSO 4 7H 2 O 0.0016g, ZnSO 4 7H 2 O 0.0014g, CoCl 2 0.002 g), 1 mL of trace element mixture was added to every 100 mL of liquid matrix), and the mixture was placed in a biochemical incubator for culture. The inoculation amount of the white rot fungus after ARTP mutagenesis in the sterilized slurry was: based on the absolute dry slurry, the number of white rot fungus spores added per 100 g of absolute dry slurry was 3×10 8 The culture temperature was 30°C, the culture humidity was 75% RH, and the culture time was 32 days.

[0056] The steps for preparing the spore suspension of white rot fungi after mutagenesis are the same as those in Example 1.

[0057] (3) After washing the pulp treated with white rot fungi, the pulp was refined at a pulp concentration of 25%, with the gap between the first-stage milling discs being 0.4 mm and the gap between the second-stage milling discs being 0.2 mm.

[0058] (4) The pulp after the second high-concentration refining is screened by a pulp screener, and then concentrated. After the water content in the pulp is measured, a certain amount of pulp is weighed and dispersed by a deflaker, and a sheet making machine is used to make sheets and dry them. The quantitative weight of the sheet is 60g / m 2 .

[0059] Example 3

[0060] Example 3 of the present application provides a method for preparing high-yield bamboo pulp using white rot fungi, comprising the following steps:

[0061] (1) After the bamboo chips are dusted, they are pre-impregnated with water at 100°C for 1 hour, and the material-liquid ratio of bamboo chips to water is 1:6. The bamboo chips after the hydrothermal impregnation treatment are extruded and rolled with a single-screw extruder. The extrusion diameter of the extruder is 90 mm, the compression ratio is 4:1, and the speed is 38 r / min. The extruded slurry is sterilized in a high-pressure sterilizer at 121°C for 20 minutes for use.

[0062] (2) The sterilized slurry in step (1) was inoculated with the No. 3 white rot fungus selected in Example 1 for treatment. The bacterial treatment step was as follows: the sterilized slurry was cooled under the irradiation of an ultraviolet lamp on a workbench, and after it was completely cooled, a spore suspension of the cultured white rot fungus after mutagenesis was added, and a liquid fermentation medium (the composition of the liquid fermentation medium was: 0.05 g NaCl, MgSO 4 0.05 g, (NH 4 ) 2 SO 4 0.3g, KH 2 PO 4 0.1g, CaCl 2 0.03g, distilled water 100mL, trace element mixture 1mL (each 10mL of trace element mixture contains FeSO 4 7H 2 O 0.0005g, MnSO 4 7H 2 O 0.0016g, ZnSO 4 7H 2 O 0.0014g, CoCl 2 0.002 g), 1 mL of trace element mixture was added to every 100 mL of liquid matrix), and the mixture was placed in a biochemical incubator for culture. The inoculation amount of the white rot fungus after ARTP mutagenesis treatment in the sterilized slurry was: based on the absolute dry slurry, the number of white rot fungus spores added per 100 g of absolute dry slurry was 2×10 8 The culture temperature was 30°C, the culture humidity was 75% RH, and the culture time was 28 days.

[0063] The steps for preparing the spore suspension of white rot fungi after mutagenesis are the same as those in Example 1.

[0064] (3) After washing the pulp treated with white rot fungi, the pulp was refined at a pulp concentration of 25%, with the gap between the first-stage milling discs being 0.4 mm and the gap between the second-stage milling discs being 0.2 mm.

[0065] (4) The pulp after the second high-concentration refining is screened by a pulp screener, and then concentrated. After the water content in the pulp is measured, a certain amount of pulp is weighed and dispersed by a deflaker, and a sheet making machine is used to make sheets and dry them. The quantitative weight of the sheet is 60g / m 2 .

[0066] Comparative Example 1

[0067] The difference between the embodiment 1 and the embodiment 1 is that the pulp after extrusion in step (1) is directly subjected to pulping treatment without being treated with white rot fungi, and the other process conditions are the same.

[0068] Comparative Example 2

[0069] The difference between the method and Example 1 is that the white rot fungi inoculated in step (3) are those that have not been subjected to ARTP mutagenesis treatment, that is, an equal amount of white rot fungi cultured on a solid medium are directly inoculated, and other process conditions are the same.

[0070] The qualified pulp samples obtained after the second refining in Example 1, Comparative Example 1 and Comparative Example 2 were tested for their physical properties by using a fiber analyzer before sheet making, and the fiber morphology of the pulp samples obtained under different conditions was analyzed. The results are shown in Table 2 below:

[0071] Table 2

[0072]

[0073] As shown in Table 2, the number average length and mass average length of bamboo pulp treated with post-mutation white rot fungi are higher than those of pulp not treated with post-mutation white rot fungi and pulp not treated with post-mutation white rot fungi. This indicates that after bamboo is treated with post-mutation white rot fungi, the fiber morphology of the pulp is conducive to improving the physical strength and tightness of the finished paper, and the physical properties of the paper are improved.

[0074] The specific surface area and pore size of the fibers in the qualified pulp samples obtained after the second refining in Example 1, Comparative Example 1 and Comparative Example 2 were tested using a Quantachrome NOVA specific surface and pore size distribution analyzer. The specific surface area and average pore size of the fibers were calculated based on the adsorption isotherm curve, the BET equation (Brunauer-Emmett-Teller) and the Barrett-Joyner-Halenda (BJH) model, and the results are shown in Table 3 below:

[0075] Table 3

[0076] sample <![CDATA[MBET specific surface area (m 2 / g)]]> BJH pore size (nm) Comparative Example 1 0.899 1.193 Comparative Example 2 0.901 1.218 Example 1 0.903 1.269

[0077] The test results in Table 3 show that the specific surface area and pore size of the pulp fiber treated with white rot fungi after mutation are increased compared with the pulp fiber treated with white rot fungi without mutation and the pulp fiber treated with white rot fungi without mutation.

[0078] According to the method of the US Renewable Energy Center (NREL / TP-510-42618), the chemical components of the qualified pulp samples obtained after the second refining in Example 1, Comparative Example 1 and Comparative Example 2 were analyzed, and the results are shown in Table 4 below:

[0079] Table 4

[0080] sample Hemicellulose degradation rate (%) Lignin degradation rate (%) Comparative Example 1 4.58 7.69 Comparative Example 2 35.74 18.39 Example 1 43.62 13.55

[0081] The results in Table 4 show that the hemicellulose degradation rate of the pulp treated with induced white rot fungi is the highest, and the lignin degradation rate is lower than that of the pulp not treated with induced white rot fungi, but higher than that of the pulp not treated with white rot fungi.

[0082] In addition, the refining energy consumption of the pulp treated with hydrothermal pretreatment, single screw extrusion and induced white rot fungi at high concentration was reduced from 385kWh / t to 362kWh / t, a decrease of 6.4%, compared with the refining energy consumption of the pulp treated with hydrothermal pretreatment, single screw extrusion and no white rot fungi. The refining energy consumption of the pulp treated with no induced white rot fungi was 378kWh / t, a decrease of 1.8% compared with the refining energy consumption of the pulp treated with no white rot fungi.

[0083] The slurry sheets in Example 1, Comparative Example 1 and Comparative Example 2 were tested, and the results are shown in Table 5 below:

[0084] Table 5

[0085]

[0086] It can be seen from Table 5 that the compactness, bursting index, tensile strength and tearing index of the finished paper are improved after the treatment with the induced white rot fungus. Combined with the analysis of the pulp fiber morphology in Table 2, it can be seen that the fiber kink index increases, indicating that the fiber becomes softer and is not easily cut during the pulping process, which improves the bonding force between the paper fibers, thereby improving the compactness, bursting index and other physical strengths of the finished paper.

[0087] In the method for preparing high-yield bamboo pulp using white rot fungi in the embodiment of the present application, the bamboo chips are first subjected to hydrothermal pretreatment, and then subjected to single-screw extrusion and decomposition to fully swell the bamboo chips, so that the extruded bamboo filaments are more dispersed and loose. Compared with the bamboo chips, the accessibility of the white rot fungi hyphae to the bamboo filaments is higher, that is, the contact is more complete.

[0088] After being treated with mutagenic white rot fungi, cavities and grooves appeared in the bamboo, and the pore size and specific surface area increased. The hemicellulose and lignin in the bamboo were partially degraded, and the relaxation of the fiber cell wall was also conducive to the separation of fibers and the development of fine fibers during pulping, which saved energy and helped the interweaving and bonding of fibers when forming paper sheets. Since no chemicals were added during the pulping process, pulping wastewater was easier to degrade and energy consumption was lower.

[0089] In addition, after ARTP mutagenesis, a white rot fungus strain with strong hemicellulose degradation ability and weak lignin degradation ability was screened out. The hemicellulose degradation rate of bamboo pulp treated with this strain was higher than that of bamboo pulp treated with unmutated white rot fungi. Under the same treatment conditions, the physical properties of bamboo pulp treated with white rot fungi after ARTP mutagenesis were better than those of bamboo pulp treated with unmutated white rot fungi and without added bacteria.

[0090] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for preparing high-yield bamboo pulp using white rot fungi, characterized in that: The following steps are involved: The bamboo chips are subjected to hydrothermal pretreatment; The hydrothermally pretreated bamboo chips are subjected to pulping treatment to obtain extruded pulp; Sterilizing the extruded slurry to obtain a sterilized slurry; Inoculate the sterilized slurry with white rot fungi that have been subjected to ARTP mutagenesis treatment, and perform microbial culture treatment to obtain a slurry treated with microorganisms; the white rot fungi are Phanerochaete chrysosporium, the ARTP mutagenesis temperature is 25-35°C, the mutagenesis time is 100s, and the helium flow rate is 5-15 SLM; 1 mL of the spore suspension of Phanerochaete chrysosporium after mutagenesis treatment is placed in a hemicellulose liquid culture medium and cultured in the dark for a period of time, and 90 μL of the cultured bacterial suspension is respectively applied to a hemicellulose-guaiacol solid culture medium and a hemicellulose-aniline blue solid culture medium, the laccase produced by the white rot fungi will react with guaiacol to develop a color, and the peroxide-type enzyme produced will react with aniline blue to produce a fading reaction, and the target strain with a bacterial ring diameter of 3.0 cm and no discoloration phenomenon is screened out; the bacterial ring diameter is 3.0 cm and the fading circle diameter is 3.2 cm for subsequent biopulping; The inoculation amount of white rot fungi after ARTP mutagenesis in the sterilized slurry is: based on the absolute dry slurry, the number of white rot fungi spores added per 100 g of absolute dry slurry is 2×10 8 ~3×10 8 The conditions for microbial culture treatment are as follows: the culture temperature is 28-32 ℃, the culture humidity is 65-85%RH, and the culture time is 28-35 days; The pulp treated with the microorganisms is subjected to pulping treatment to obtain bamboo pulp.

2. The method for preparing high-yield bamboo pulp using white rot fungi according to claim 1, characterized in that: The temperature of the hydrothermal pretreatment is 80-100°C and the time is 1-3 h.

3. The method for preparing high-yield bamboo pulp using white rot fungi according to claim 1, characterized in that: During the hydrothermal pretreatment, the solid-liquid ratio is 1:2-1:

6.

4. The method for preparing high-yield bamboo pulp using white rot fungi according to claim 1, characterized in that: The slurry extrusion process is carried out in a single-screw extrusion deflaking machine, the extrusion diameter of the single-screw extrusion deflaking machine is 80-100 mm, the compression ratio is 3:1-4:1, and the rotation speed is 30-40 r / min.

5. The method for preparing high-yield bamboo pulp using white rot fungi according to claim 1, characterized in that: The sterilization treatment is carried out in a high pressure sterilizer, the sterilization pressure is 0.1-0.14 MPa, the sterilization temperature is 120-130°C, and the sterilization time is 20-40 min.

6. The method for preparing high-yield bamboo pulp using white rot fungi according to claim 1, characterized in that: The number of refining stages in the refining treatment is 2 stages, the gap between the grinding discs in the first stage is 0.4-0.2 mm, the gap between the grinding discs in the second stage is 0.2-0.1 mm, and the refining concentration is 20%-30%.

7. A method for preparing high-yield bamboo pulp using white rot fungi according to any one of claims 1 to 6, characterized in that: The method also includes the steps of screening, concentrating and sheeting the bamboo pulp.

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