Method for promoting white-rot fungi to degrade plastics through pretreatment technology

Abstract

The invention relates to the technical field of solid waste treatment, and discloses a method for promoting white-rot fungi to degrade plastics by a pretreatment technology, which comprises the following steps: adding plastics into dimethylbenzene, heating and stirring until the plastics are completely dissolved, uniformly spreading on a glass plate, cooling, separating, air-drying to obtain a plastic film, and shearing the plastic film into a size of 30mm * 30mm to obtain an original polystyrene plastic film; an original polystyrene plastic film is put into a beaker for pretreatment, white-rot fungi degradation is performed after pretreatment, and the plastic degradation effect of the white-rot fungi is enhanced; the problems that in the prior art, plastic molecular chains cannot be efficiently decomposed, the degradation efficiency is low, the energy consumption is high, secondary pollutants can be generated in the degradation process, and engineering application is difficult to achieve are solved.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment technology, and in particular to a method for promoting the degradation of plastics by white-rot fungi through pretreatment technology. Background Technology

[0002] With the rapid increase in global plastic consumption, the large-scale management and scientific disposal of plastic waste has become a pressing global environmental challenge. Polystyrene, in particular, has seen widespread application, ranging from everyday packaging and electronic devices to building materials, leading to its continuous accumulation in the natural environment and creating a severe chain reaction of environmental pollution. This accumulated plastic not only disrupts the balance of ecosystems and interferes with the survival and reproduction of plants and animals, but also poses a potential threat to human health through bioaccumulation in the food chain, drawing significant global attention to the control of plastic pollution.

[0003] Currently, various technical pathways for plastic degradation have been explored, including biodegradation, photodegradation, thermal degradation, and chemical degradation. However, each method has significant limitations in its applicability. Taking biodegradation as an example, although it has the natural advantage of being environmentally friendly, most microorganisms cannot efficiently decompose plastic molecular chains due to the metabolic characteristics of microorganisms. Furthermore, the degradation efficiency is heavily dependent on multiple factors such as the type of microorganism, ambient temperature, and pH value, making it difficult to promote on a large scale in practical applications. Photodegradation and thermal degradation often require specific extreme conditions, which not only consume a lot of energy but may also produce secondary pollutants. Although chemical degradation has a faster reaction rate, it is easily constrained by reagent costs and the control of reaction conditions, making it difficult to achieve engineering applications.

[0004] This demonstrates that the field of plastic degradation still faces numerous technological bottlenecks, and a mature technological system that can be widely applied in engineering practice has not yet been formed. Therefore, there is an urgent need for a method to degrade plastics that can reduce the environmental accumulation of plastic waste at its source and has significant ecological and environmental value in reducing carbon emissions, reducing energy consumption, and curbing the spread of pollutants. Summary of the Invention

[0005] The present invention aims to provide a pretreatment technology to promote the degradation of plastics by white-rot fungi, in order to solve the problems of existing technologies that cannot efficiently decompose plastic molecular chains, have low degradation efficiency, high energy consumption, generate secondary pollutants during the degradation process, and are difficult to achieve engineering applications.

[0006] To achieve the above objectives, the present invention provides the following method:

[0007] The present invention provides a pretreatment technique to promote the degradation of plastics by white-rot fungi:

[0008] Plastic is added to xylene, heated and stirred until completely dissolved, spread evenly on a glass plate, cooled, separated, and air-dried to obtain a plastic film. The plastic film is cut into 30mm×30mm pieces to obtain the original polystyrene plastic film. The original polystyrene plastic film is placed in a beaker for pretreatment. After pretreatment, it is subjected to degradation by white-rot fungi to enhance the degradation effect of white-rot fungi on plastic.

[0009] Preferably, the plastic is polylactic acid, polystyrene, or a product containing polylactic acid or polystyrene.

[0010] Preferably, the heating temperature is 80~90℃, the stirring rate is 100~150r / min, and the stirring time is 0.5~1h.

[0011] Preferably, the step of pretreating the raw polystyrene plastic film in a beaker includes: placing the raw polystyrene plastic film in the beaker, then adding a 20%~50% H2O2 solution to the beaker, and then subjecting it to ultraviolet radiation to construct a reaction system; the ultraviolet light source for the ultraviolet radiation is an LED ultraviolet lamp with a wavelength of 280~370nm, the LED ultraviolet lamp is fixed to the top of the beaker, maintaining a distance of 15cm from the mouth of the beaker, and then the irradiation is turned on.

[0012] Preferably, the pretreatment temperature conditions are: 25°C, and the pretreatment time is 7-10 days.

[0013] Preferably, during the pretreatment process, a certain volume of reaction solution is extracted every 24 hours, filtered through a 0.22 μm microporous filter, and then analyzed using a spectrophotometer via a titanium oxalate colorimetric reaction at the maximum absorption wavelength λ. max The absorbance was measured at 400 nm to detect the concentration of H2O2 solution. Based on the detection results, a quantitative amount of H2O2 solution was added to the reaction solution to ensure that the oxidation rate of polystyrene remained stable.

[0014] Preferably, after pretreatment, the polystyrene film is soaked in deionized water for 2 hours, rinsed repeatedly, and dried in a 40°C oven for 24 hours to obtain the pretreated polystyrene film.

[0015] Preferably, the step of pretreatment followed by degradation of white-rot fungi includes: preparing a culture medium composed of 200 g / L potato extract, 20 g / L glucose, 1.5 g / L magnesium sulfate heptahydrate, 3 g / L potassium dihydrogen phosphate, and 20 g / L agar powder, adjusting the pH of the *Phanerochaete chrysosporium* culture medium to 7-7.5; inoculating *Phanerochaete chrysosporium* onto the sterilized culture medium under sterile conditions, and culturing it in a 37°C incubator for 2-3 days until the logarithmic growth phase is reached, obtaining a *Phanerochaete chrysosporium* culture; placing the pretreated polystyrene plastic film in the *Phanerochaete chrysosporium* culture for co-culturing, with a cycle of 7 days. After each cycle, the pretreated polystyrene plastic film is washed and placed in a new *Phanerochaete chrysosporium* culture, and this process is repeated for 5-6 cycles to degrade the white-rot fungi.

[0016] The beneficial effects of this invention are as follows: This invention pre-treats plastics by placing them in a synergistic reaction system composed of ultraviolet radiation and hydrogen peroxide for 7 days. Then, the pre-treated plastics are co-cultured with white-rot fungi in their logarithmic growth phase, achieving efficient degradation of the plastics. Scanning electron microscopy revealed pores and cracks on the surface of the pre-treated plastics. After 35 days of co-culture, the original plastics did not pyrolyze, while the surface morphology of the pre-treated plastics showed significant pyrolysis changes and was covered with a large number of white-rot fungal hyphae. Plastic quality testing showed a significant decrease in plastic mass before and after the reaction. The pre-treated plastics exhibited a significantly increased weight loss rate, and decreased number-average and weight-average molecular weights, indicating that the plastics were degraded by the white-rot fungi. Therefore, the method provided by this invention can enhance the degradation effect of white-rot fungi on plastics. The process is simple and easy to implement, has prospects for large-scale application, effectively achieves the harmless degradation of plastic pollutants, and is of great significance for environmental protection. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0018] Figure 1 Images of polystyrene plastic film provided in embodiments of the present invention, wherein (a) is an image of the original polystyrene plastic film, (b) is an image of the pretreated polystyrene plastic film, and (c) is an image of the pretreated polystyrene plastic film after 35 days of biodegradation;

[0019] Figure 2These are images of the co-culture experiment of polystyrene plastic film and *Phanerochaete chrysosporium* provided in the embodiments of the present invention, wherein (a) is an image of the original polystyrene plastic film and *Phanerochaete chrysosporium* co-culture, and (b) is an image of the pretreated polystyrene plastic film and *Phanerochaete chrysosporium* co-culture.

[0020] Figure 3 Scanning electron microscope images of pretreated polystyrene plastic films in Example 1 and Comparative Examples 1 and 2, provided as embodiments of the present invention.

[0021] Figure 4 Scanning electron microscope images of polystyrene plastic films after 35 days of biodegradation in Example 1 and Comparative Examples 1 and 2, which are provided as embodiments of the present invention.

[0022] Figure 5 Infrared spectra of polystyrene plastic films in Example 1 and Comparative Examples 1 and 2 provided for embodiments of the present invention;

[0023] Figure 6 In Example 1, which is an embodiment of the present invention, and in Comparative Examples 1 and 2, the mass change of the polystyrene plastic film during the biodegradation process was detected.

[0024] Figure 7 The weight loss rate of polystyrene plastic film detected during the biodegradation process in Example 1 and Comparative Examples 1 and 2 provided for the embodiments of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product, or end that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or ends.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] Currently, various technical pathways for plastic degradation have been explored, including biodegradation, photodegradation, thermal degradation, and chemical degradation. However, each method has significant limitations in its applicability. Taking biodegradation as an example, although it has the natural advantage of being environmentally friendly, most microorganisms cannot efficiently decompose plastic molecular chains due to the metabolic characteristics of microorganisms. Furthermore, the degradation efficiency is heavily dependent on multiple factors such as the type of microorganism, ambient temperature, and pH value, making it difficult to promote on a large scale in practical applications. Photodegradation and thermal degradation often require specific extreme conditions, which not only consume a lot of energy but may also produce secondary pollutants. Although chemical degradation has a faster reaction rate, it is easily constrained by reagent costs and the control of reaction conditions, making it difficult to achieve engineering applications.

[0029] This demonstrates that the field of plastic degradation still faces numerous technological bottlenecks, and a mature technological system that can be widely applied in engineering practice has not yet been formed. Therefore, there is an urgent need for a method to degrade plastics that can reduce the environmental accumulation of plastic waste at its source and has significant ecological and environmental value in reducing carbon emissions, reducing energy consumption, and curbing the spread of pollutants.

[0030] The present invention aims to provide a pretreatment technology to promote the degradation of plastics by white-rot fungi, in order to solve the problems of existing technologies that cannot efficiently decompose plastic molecular chains, have low degradation efficiency, high energy consumption, generate secondary pollutants during the degradation process, and are difficult to achieve engineering applications.

[0031] This invention provides a method for promoting the degradation of plastics by white-rot fungi through pretreatment, comprising the following steps:

[0032] Add plastic to xylene, heat and stir until completely dissolved, spread evenly on a glass plate, cool, separate, and air dry to obtain a plastic film; the plastic is polylactic acid, polystyrene, or a product containing polylactic acid or polystyrene; the heating temperature is 80~90℃, the stirring rate is 100~150r / min, and the stirring time is 0.5~1h;

[0033] Cut the plastic film into 30mm x 30mm pieces to obtain the original polystyrene plastic film;

[0034] Raw polystyrene plastic film was pretreated in a beaker before being subjected to degradation by white-rot fungi to enhance the degradation effect of the fungi on the plastic. The raw polystyrene plastic film was placed in the beaker, and then a 20%–50% H₂O₂ solution was added. Ultraviolet radiation was then applied to establish the reaction system. An LED UV lamp with a wavelength of 280–370 nm was used as the UV light source. The LED UV lamp was fixed to the top of the beaker, maintained at a distance of 15 cm from the rim, and irradiated. The pretreatment temperature was 25℃ for 7–10 days. During the pretreatment, a certain volume of the reaction solution was extracted every 24 hours, filtered through a 0.22 μm microporous filter, and analyzed using a spectrophotometer. The colorimetric reaction was performed using titanium oxalate, and the sample was analyzed at the maximum absorption wavelength λ. max The absorbance was measured at 400 nm to detect the concentration of H2O2 solution. Based on the detection results, a quantitative amount of H2O2 solution was added to the reaction solution to ensure that the oxidation rate of polystyrene remained stable. After pretreatment, the polystyrene was soaked in deionized water for 2 hours, rinsed repeatedly, and dried in an oven at 40°C for 24 hours to obtain the pretreated polystyrene plastic film. A culture medium was prepared, consisting of 200 g / L potato extract, 20 g / L glucose, 1.5 g / L magnesium sulfate heptahydrate, 3 g / L potassium dihydrogen phosphate, and 20 g / L agar powder. The pH of the *Phanerochaete chrysosporium* culture medium was adjusted to 7-7.5.

[0035] The preparation steps of potato extract are as follows: Peel and cut fresh potatoes into pieces, mix potatoes and deionized water at a ratio of 1:5 (mass-volume ratio, g:mL), boil for 30-40 minutes, filter with double-layer sterile gauze, and take the filtrate to make up to the corresponding concentration. The starch content of the potatoes should be ≥15%. The pH value of the culture medium is adjusted by using a 1 mol / L hydrochloric acid solution or a 0.5 mol / L sodium hydroxide solution. During the adjustment process, a precision pH meter is used for real-time monitoring with an error range of ±0.1. The preparation sequence of the culture medium is as follows: First, mix the potato extract with potassium dihydrogen phosphate and magnesium sulfate heptahydrate and stir for 10-15 minutes until completely dissolved. Then, add glucose and agar powder, continue stirring for 5-8 minutes, adjust the pH value, and finally make up to the required volume. After the culture medium is made up to the required volume, autoclave it at 121℃ and 0.1MPa for 25-30 minutes. After sterilization, quickly place it on a sterile operating table to cool. The cooling rate is controlled at 1-2℃ / min to avoid crystallization of agar powder.

[0036] Under sterile conditions, *Phanerochaete chrysosporium* was inoculated onto a sterilized culture medium and cultured at 37°C for 2-3 days until the logarithmic growth phase was reached, yielding a *Phanerochaete chrysosporium* culture. A pretreated polystyrene plastic film was then placed within the *Phanerochaete chrysosporium* culture for co-culture, with a 7-day cycle. After each cycle, the pretreated polystyrene plastic film was washed and placed into a new *Phanerochaete chrysosporium* culture. This process was repeated 5-6 times to allow for the degradation of the white-rot fungus.

[0037] Example 1

[0038] 1. Pretreatment of plastics

[0039] Polystyrene plastic raw material is added to xylene, heated and stirred until completely dissolved, spread evenly on a glass plate, cooled, separated, and air-dried. Then the plastic film is cut into 30mm×30mm sizes to obtain the original polystyrene plastic film.

[0040] The original plastic film was placed in a beaker, and then 20 ml of 30% H2O2 was added before ultraviolet irradiation was applied to construct the reaction system. An LED ultraviolet lamp with a wavelength of 365 nm was selected as the ultraviolet light source, fixed at the top of the beaker, 15 cm away from the mouth of the beaker, and turned on for irradiation.

[0041] Since H2O2 is continuously consumed during the reaction, a certain volume of the reaction solution needs to be extracted every 24 hours. After filtration through a 0.22μm microporous filter, the absorbance is measured at the maximum absorption wavelength λmax=400nm using a spectrophotometer and titanium oxalate (IV) colorimetric reaction to detect the H2O2 concentration. Based on the detection results, a quantitative amount of H2O2 is added to the suspension to ensure that the oxidation rate of polystyrene remains stable.

[0042] Pre-treatment lasted 7 days. After the treatment, the plastic film was soaked in deionized water for 2 hours, rinsed repeatedly, and dried in a 40℃ oven for 24 hours to obtain the pre-treated polystyrene plastic film.

[0043] 2. Culture of *Phanerochaete chrysosporium*

[0044] (1) Source of strain: China Center for Type Culture Collection (Wuhan), strain number: BKMF-1767, CCTCC, number AF96007.

[0045] (2) The composition of the culture medium: 200 g / L potato extract, 20 g / L glucose, 1.5 g / L magnesium sulfate heptahydrate, 3 g / L potassium dihydrogen phosphate and 20 g / L agar powder, with a pH of 7.5.

[0046] (3) Culture method: In a sterile environment, Phanerochaete chrysosporium was inoculated onto a sterilized culture medium and cultured in a 37°C incubator for 2 days to reach the logarithmic growth phase, at which time the biomass of Phanerochaete chrysosporium was the most abundant, and the culture of Phanerochaete chrysosporium was obtained.

[0047] 3. Co-culture of plastic and white-rot fungi

[0048] The pretreated polystyrene plastic film was placed in the obtained Phanerochaete chrysosporium culture for co-culture, with a cycle of 7 days. After each cycle, the plastic film was washed and placed in a new Phanerochaete chrysosporium culture for five cycles, for a total of 35 days.

[0049] 4. Biodegradation and Detection Methods

[0050] Polystyrene plastics pretreated for 7 days and those biodegraded for 35 days were observed and tested. The surface morphology of the plastic films was observed using scanning electron microscopy, changes in functional groups were detected using infrared spectroscopy, and the molecular weight difference between the pre- and post-treatment samples was detected by gel permeation chromatography. The mass of the plastic films was measured throughout the co-culture process, and the change in film mass was used to quantify the degradation effect of *Phanerochaete chrysosporium* on the plastic films.

[0051] 5. Test Results

[0052] (1) Scanning electron microscopy observation results

[0053] like Figure 3 As shown in the comparison of electron micrographs of polystyrene plastic film before and after pretreatment, it can be seen that the original polystyrene plastic film surface is smooth and flat before pretreatment; after synergistic pretreatment with ultraviolet radiation and hydrogen peroxide, pores and cracks appear on the surface of the plastic film. This indicates that synergistic aging pretreatment of plastic film with ultraviolet radiation and hydrogen peroxide can significantly change its surface properties, thereby affecting the colonization of *Phanerochaete chrysosporium*.

[0054] Figure 4 These are electron microscope images of polystyrene plastic film after 35 days of biodegradation. It can be seen that the original polystyrene plastic film only has a few wrinkles on the surface after biodegradation, and no *Phanerochaete chrysosporium* is attached. However, after the polystyrene plastic film pretreated with ultraviolet radiation and hydrogen peroxide, more obvious wrinkles and larger pores were found on its surface after biodegradation. At the same time, a large number of *Phanerochaete chrysosporium* can be observed attached to the inside of the plastic film, indicating that significant biodegradation has occurred.

[0055] (2) Infrared spectroscopy detection results

[0056] like Figure 5As shown in the infrared spectrum, significant changes in the surface functional groups of the polystyrene film before and after pretreatment and biodegradation are observed. Changes in absorption peaks at 3025 and 2922 cm⁻¹ are observed before and after pretreatment, which is attributed to the CH stretching vibration of the aromatic ring. A carbonyl (C=O) absorption peak is observed at 1602 cm⁻¹, indicating the introduction of polar groups into the polyethylene backbone, leading to a hydrophobic to hydrophilic transformation of the polyethylene plastic, which is more conducive to the adhesion of *Phanerochaete chrysosporium* to the polystyrene film. The increase in oxygen-containing functional groups may be due to the breakage of CH bonds under ultraviolet light, reacting with oxygen to generate peroxide radicals (CO). These peroxide radicals can absorb hydrogen atoms from the surrounding environment, forming hydroperoxide groups (COOH), which then further decompose into other products (C=O). After co-culturing with *Phanerochaete chrysosporium*, the carbonyl (C=O) absorption peak in the infrared spectrum of the plastic film becomes more pronounced, indicating further oxidative degradation of the polystyrene film.

[0057] (3) Results of plastic film quality testing

[0058] like Figure 6 As shown, the changes in the mass of the plastic film during the biodegradation process are detected over time. As the biodegradation cycle progresses, the mass of the original polystyrene plastic film does not fluctuate significantly, while the mass of the polystyrene plastic film after synergistic pretreatment with ultraviolet radiation and hydrogen peroxide shows a clear decreasing trend.

[0059] (4) Calculation results of plastic weight loss rate

[0060] like Figure 7 The figure shows the change in weight loss rate of the plastic film during the biodegradation process. After 35 days of biodegradation, the original polystyrene plastic film had a weight loss rate of 6.95% on day 35; while the polystyrene plastic film that underwent synergistic pretreatment with ultraviolet radiation and hydrogen peroxide had a weight loss rate of 25.75% on day 35.

[0061] (5) Gel permeation chromatography results

[0062] Table 1 shows the changes in weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the plastic film before and after 35 days of biodegradation. Table 1 shows that pretreatment with synergistic ultraviolet radiation and hydrogen peroxide before biodegradation can significantly reduce the molecular weight of polystyrene plastic.

[0063] Table 1. Changes in Mw and Mn of polystyrene plastic film before and after biodegradation in Example 1

[0064] sample Mw Mn Original PS 161655 300642 After the original PS biodegradation 149757 297810 <![CDATA[After biodegradation by UV + H2O2-PS]]> 77242 238639

[0065] Comparative Example 1

[0066] The difference from Example 1 is that the pretreatment method for the plastic film is only hydrogen peroxide pretreatment.

[0067] The prepared raw polystyrene plastic film was placed in a hydrogen peroxide solution and pretreated in the dark for 7 days. Figure 3 As shown, no significant changes were observed on the surface of the plastic film after pretreatment with hydrogen peroxide alone. Subsequently, the pretreated polystyrene plastic film was co-cultured with *Phanerochaete chrysosporium* for 35 days. Figure 4 As shown, only a few wrinkles appear on the surface of the biodegraded plastic film, such as Figure 7 As shown, the weight loss rate on day 35 was 7.89%, and the changes in Mw and Mn are shown in Table 2.

[0068] Comparative Example 2

[0069] The difference from Example 1 is that the pretreatment method for the plastic film is only ultraviolet radiation pretreatment.

[0070] The prepared raw polystyrene plastic film was placed in a beaker and pretreated under ultraviolet radiation for 7 days. Figure 3 As shown, the surface of the plastic film did not show significant changes after separate pretreatment with ultraviolet radiation. Subsequently, the pretreated polystyrene plastic film was co-cultured with *Phanerochaete chrysosporium* for 35 days. Figure 4 As shown, after biodegradation, the plastic film surface only showed a few wrinkles and a few *Phanerochaete chrysosporium* fungi attached, such as... Figure 7 As shown, the weight loss rate on day 35 was 7.39%, and the changes in Mw and Mn are shown in Table 2.

[0071] Table 2. Changes in Mw and Mn of polystyrene plastic films before and after biodegradation in Comparative Examples 1 and 2.

[0072] sample Mw Mn <![CDATA[After biodegradation of H2O2-PS]]> 157833 310984 UV-PS biodegradation 121539 253882

[0073] In summary, pretreatment of polystyrene plastics can significantly alter their surface morphology and increase their hydrophilicity. Pores and cracks were observed in the pretreated polystyrene film. During co-cultivation, the pretreated film developed obvious cracks. The attachment and growth of *Phanerochaete chrysosporium* on the polystyrene film were also observed. Infrared spectroscopy revealed an enhanced carbonyl (C=O) absorption peak after pretreatment, indicating oxidation of the pretreated film. Quality testing results showed that the pretreatment process promoted the pyrolysis of polystyrene plastics during biodegradation, accelerating its quality decline. Significant changes in Mw and Mn also indicate large-scale pyrolysis of the polymer film, forming smaller polymers and molecules.

[0074] The beneficial effects of this invention are as follows: This invention pre-treats plastics by placing them in a synergistic reaction system composed of ultraviolet radiation and hydrogen peroxide for 7 days. Then, the pre-treated plastics are co-cultured with white-rot fungi in their logarithmic growth phase, achieving efficient degradation of the plastics. Scanning electron microscopy revealed pores and cracks on the surface of the pre-treated plastics. After 35 days of co-culture, the original plastics did not pyrolyze, while the surface morphology of the pre-treated plastics showed significant pyrolysis changes and was covered with a large number of white-rot fungal hyphae. Plastic quality testing showed a significant decrease in plastic mass before and after the reaction. The pre-treated plastics exhibited a significantly increased weight loss rate, and decreased number-average and weight-average molecular weights, indicating that the plastics were degraded by the white-rot fungi. Therefore, the method provided by this invention can enhance the degradation effect of white-rot fungi on plastics. The process is simple and easy to implement, has prospects for large-scale application, effectively achieves the harmless degradation of plastic pollutants, and is of great significance for environmental protection.

[0075] The above descriptions are merely embodiments of the present invention. Commonly known technical solutions or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for promoting the degradation of plastics by white-rot fungi through pretreatment technology, characterized in that, The method includes: Plastic is added to xylene, heated and stirred until completely dissolved, spread evenly on a glass plate, cooled, separated, and air-dried to obtain a plastic film. The plastic film is then cut into 30mm×30mm sizes to obtain the original polystyrene plastic film. The original polystyrene plastic film was placed in a beaker for pretreatment. After pretreatment, it was subjected to degradation by white-rot fungi to enhance the degradation effect of white-rot fungi on plastic.

2. The method for promoting the degradation of plastics by white-rot fungi using a pretreatment technique according to claim 1, characterized in that: The plastic is polylactic acid, polystyrene, or a product containing polylactic acid or polystyrene.

3. The method for promoting the degradation of plastics by white-rot fungi using a pretreatment technique according to claim 1, characterized in that: The heating temperature is 80~90℃, the stirring rate is 100~150r / min, and the stirring time is 0.5~1h.

4. The method for promoting the degradation of plastics by white-rot fungi using a pretreatment technique according to claim 1, characterized in that, The step of placing the original polystyrene plastic film into a beaker for pretreatment includes: The original polystyrene plastic film was placed in a beaker, and then a 20%~50% H2O2 solution was added to the beaker, followed by ultraviolet radiation to construct the reaction system. The ultraviolet light source for the ultraviolet radiation is an LED ultraviolet lamp with a wavelength of 280~370nm. The LED ultraviolet lamp is fixed to the top of the beaker, maintaining a distance of 15cm from the mouth of the beaker, and then turned on for irradiation.

5. The method for promoting the degradation of plastics by white-rot fungi using a pretreatment technique according to claim 4, characterized in that: The pretreatment temperature conditions are: 25℃, pretreatment for 7-10 days.

6. The method for promoting the degradation of plastics by white-rot fungi using a pretreatment technique according to claim 4, characterized in that: During the pretreatment process, a certain volume of reaction solution was extracted every 24 hours, filtered through a 0.22 μm microporous filter, and then analyzed using a spectrophotometer via a titanium oxalate colorimetric reaction at the maximum absorption wavelength λ. max The absorbance was measured at 400 nm to detect the concentration of H2O2 solution. Based on the detection results, a quantitative amount of H2O2 solution was added to the reaction solution to ensure that the oxidation rate of polystyrene remained stable.

7. The method for promoting the degradation of plastics by white-rot fungi using a pretreatment technique according to claim 5, characterized in that: After pretreatment, the polystyrene film was soaked in deionized water for 2 hours, rinsed repeatedly, and dried in a 40°C oven for 24 hours to obtain the pretreated polystyrene film.

8. The method for promoting the degradation of plastics by white-rot fungi using a pretreatment technique according to claim 7, characterized in that, The step of pretreatment followed by degradation by white-rot fungi includes: A culture medium was prepared, the components of which were: 200 g / L potato extract, 20 g / L glucose, 1.5 g / L magnesium sulfate heptahydrate, 3 g / L potassium dihydrogen phosphate and 20 g / L agar powder, and the pH of the *Phanerochaete chrysosporium* culture medium was adjusted to 7-7.

5. Under aseptic conditions, *Phanerochaete chrysosporium* was inoculated onto the sterilized culture medium and cultured in a 37°C incubator for 2-3 days until the logarithmic growth phase was reached, thus obtaining a *Phanerochaete chrysosporium* culture. The pretreated polystyrene plastic film was placed in the culture of *Phanerochaete chrysosporium* for co-culture, with a cycle of 7 days. After each cycle, the pretreated polystyrene plastic film was washed and placed in a new culture of *Phanerochaete chrysosporium* for 5-6 cycles to degrade the white-rot fungus.

Images