Bacterial strain for degrading polyethylene plastic as well as separation method and application of bacterial strain

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to a bacterial strain for degrading polyethylene plastics and a separation method and application thereof. The bacterial strain is PEI LAB L-A-17, the classification name of the bacterial strain is Brevundimonas huaxiensis, the bacterial strain is preserved in the China General Microbiological Culture Collection Center on September 26, 2024, and the preservation number is CGMCC No.32083. The invention further discloses a preparation method of the bacterial strain. The strain is separated and screened from intestinal tract fluid of larvae of Lasioderma serricorne gnawing polyethylene plastic, the strain grows by taking the polyethylene plastic as a unique carbon source, and polyethylene can be effectively degraded. The invention provides a new strain resource for biodegradation of polyethylene, and has important significance on treatment of polyethylene plastic wastes.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and in particular relates to a strain for degrading polyethylene plastics, and a separation method and application thereof. Background Art

[0002] Polyethylene (PE) is a widely used synthetic material with ethylene as a monomer. It is non-toxic, odorless, anti-oxidant, and acid and alkali resistant. Due to its excellent physical and chemical properties, it is widely used in packaging, construction, automobiles, electronics and other fields. However, with the mass production and consumption of polyethylene plastics, the "white pollution" problem it brings is becoming increasingly serious. Due to the inefficiency of recycling waste plastics, most of the plastic waste is released into the environment, and is ubiquitous from land to water. At the same time, waste plastics may also become a carrier of disease transmission, enter the human body through the food chain, and cause health problems.

[0003] At present, polyethylene plastics are mostly treated by non-biological methods such as landfill incineration, which easily causes waste of resources and secondary pollution, and the treatment cost is high. Therefore, in addition to the development of new environmentally friendly plastic products, the treatment technology for the safe and green disposal of polyethylene and other plastic wastes is urgently needed to be researched and developed. The biodegradation method uses microorganisms to digest and metabolize polyethylene plastics, decompose polyethylene into small molecular compounds through enzymatic reactions, and finally convert them into harmless water, carbon dioxide and other inorganic salts. While degrading polyethylene, it can promote the recycling of carbon resources, which is of great significance to improving the ecological environment. The biodegradation method has become a research hotspot in the field of environmental protection because of its advantages such as low cost, environmental sustainability, and multiple treatment occasions. The known microorganisms that can degrade polyethylene plastics mainly include Pseudomonas, Stenotrophomonas, Klebsiella, Acinetobacter, Rhodococcus, Staphylococcus, Streptococcus and Bacillus. Most of these strains have the ability to degrade the PE surface and / or form biofilms on the PE surface.

[0004] Some prior arts have also reported on polyethylene plastic degrading bacteria. For example, patent CN117821314A discloses a method for screening polyethylene plastic degrading bacteria and its application. The patent obtains a strain with polyethylene degradation ability by acclimating and enriching the sample to be separated, transferring it to a culture medium with polyethylene as the sole carbon source and culturing it for a period of time. The obtained polyethylene plastic degrading bacteria include Ochrobactrum intermedium D2-6-1 and Pseudoxanthomonas sp. D4-2-1. Patent CN115960782B discloses a marine polyethylene plastic degrading bacteria and its application. The strain is Evansella clarkii SCSIO 43802, which is isolated from the seagrass bed ecosystem and grows with polyethylene plastic as the sole carbon source. The strain can degrade polyethylene plastic, especially degrading plastic in marine habitats.

[0005] Although biodegradation has environmental advantages, there are currently few effective microbial resources that can degrade plastic waste such as polyethylene, and the treatment efficiency is low and the degradation rate is slow, which greatly limits the promotion and application of microbial degradation of plastics. Therefore, it is still urgent to seek green and environmentally friendly degradation methods and screen new and efficient plastic degrading bacteria. Summary of the invention

[0006] In view of this, one of the purposes of the present invention is to provide a strain capable of degrading polyethylene plastic, wherein the strain can effectively degrade polyethylene plastic.

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

[0008] The strain has the function of degrading polyethylene plastic, the strain is PEI LAB LA-17, and its classification name is Brevundimonas huaxiensis. It was deposited in the General Microbiology Center of China Microbiological Culture Collection Administration on September 26, 2024, and the deposit number is CGMCC No.32083.

[0009] Furthermore, the nucleotide sequence of 16S rDNA of the strain is shown in SEQ ID NO: 1.

[0010] Furthermore, the strain is a Gram-negative bacterium, in the shape of a short rod; its colony characteristics and bacterial morphology are: light yellow, round, protruding, relatively viscous and opaque.

[0011] Furthermore, the physiological and biochemical characteristics of the strain are: negative in PEI LAB LA-17V.P test, positive in glucose acid production test, negative in CIT citrate test, negative in IND indole test, negative in GEL gelatin liquefaction test, and negative in H2S hydrogen sulfide test.

[0012] In recent years, insects feeding on polyolefin plastics have attracted the attention of researchers, the most representative of which include Tenebrio molitor, Tenebrio obscurus, Zophobas morio of the order Tenebrionidae, and Galleria mellonella and Plodia interpunctella of the order Lepidoptera. Existing studies have shown that the intestinal microorganisms of such insects are likely to play an important role in the biodegradation of polyolefin plastics. However, there are currently few cases of extracting strains from insects and using them for the degradation of polyethylene plastics. The present invention isolates and screens a polyethylene plastic-degrading bacterium from the intestinal fluid of tobacco beetle larvae that gnaw on polyethylene plastics, and the strain can grow using polyethylene plastics as the sole carbon source. The present invention provides a new bacterial strain resource for the biodegradation of polyethylene plastic mulch, and provides new resources and ideas for the treatment of polyethylene plastic waste in the environment, and has broad application prospects.

[0013] A second object of the present invention is to provide a preparation product for degrading polyethylene plastics.

[0014] To achieve the above object, the present invention adopts the following technical solutions:

[0015] A preparation product for degrading polyethylene plastic, wherein the preparation product uses the aforementioned strain as an active ingredient.

[0016] A third object of the present invention is to provide a method for separating and screening the aforementioned strains.

[0017] To achieve the above object, the present invention adopts the following technical solutions:

[0018] The method for separating and screening the aforementioned strains comprises the following steps:

[0019] 1) Insects that chew polyethylene plastics are used as the source of bacteria, and a culture medium with polyethylene plastics as the only carbon source is used for enrichment culture to obtain a culture solution containing plastic-degradable microorganisms;

[0020] 2) Purifying the culture fluid obtained in step 1) by solid TSA medium streaking method; then adding medium with polyethylene plastic as the sole carbon source for further culturing, and screening out polyethylene degrading bacteria PEI LAB LA-17.

[0021] Furthermore, the insects that gnaw on polyethylene plastic are larvae of tobacco beetles.

[0022] Furthermore, in step 1), the culture conditions are: constant temperature shaking culture at 25-35°C and 140-160r / min for 24-48 days; more preferably, constant temperature shaking culture at 30°C and 150r / min for 30 days.

[0023] Further, in step 1), the culture medium is a carbon source-free mineral salt liquid culture medium composed of the following components: K2HPO4·3H2O 0.5-1.0 g / L, KH2PO4 0.5-1.0 g / L, NH4NO3 0.7-1.3 g / L, MgSO4·7H2O 0.3-0.7 g / L, NaCl 0.003-0.007 g / L, FeSO4·7H2O 0.001-0.003 g / L, ZnSO4·7H2O 0.001-0.003 g / L, and MnSO4·H2O 0.0005-0.002 g / L.

[0024] Preferably, the carbon source-free mineral salt liquid culture medium consists of the following components: K2HPO4·3H2O 0.7 g / L, KH2PO4, 0.7 g / L, NH4NO3 1.0 g / L, MgSO4·7H2O 0.5 g / L, NaCl 0.005 g / L, FeSO4·7H2O 0.002 g / L, ZnSO4·7H2O 0.002 g / L, and MnSO4·H2O 0.001 g / L.

[0025] Further, in step 2), the solid TSA culture medium is composed of the following components: tryptone, soy peptone, sodium chloride, agar powder and distilled water; the ratio of tryptone, soy peptone, sodium chloride, agar powder and distilled water is 5-7g: 1-3g: 1-3g: 350-500mL: 5-7g.

[0026] Preferably, in the solid TSA culture medium, the ratio of tryptone, soy peptone, sodium chloride, agar powder and distilled water is 6g:2g:2g:400mL:6g.

[0027] Preferably, the method comprises the following steps:

[0028] 1. Prepare the intestinal bacterial suspension of tobacco beetle larvae;

[0029] 2. adding a carbon-free mineral salt liquid culture medium and a polyethylene film to the obtained intestinal bacteria suspension for culturing to obtain a culture solution;

[0030] 3. Take a small amount of culture solution and place it on TSA solid culture medium for plate coating. After obvious colonies grow on the plate, observe the size, color and morphology of the colonies, and mark the strains with different morphologies; purify the isolated bacteria by TSA solid culture medium streak method; add carbon-free mineral salt liquid culture with polyethylene film as the only carbon source and continue to culture, and screen out polyethylene degrading bacteria PEI LAB LA-17.

[0031] A fourth object of the present invention is to provide a method for degrading polyethylene plastic using the aforementioned strain.

[0032] To achieve the above object, the present invention adopts the following technical solutions:

[0033] The method for degrading polyethylene plastic using the aforementioned strain comprises co-culturing the strain and polyethylene plastic to degrade the polyethylene plastic; the strain grows with polyethylene as the sole carbon source.

[0034] Furthermore, the strain is cultured together with polyethylene plastic in an inorganic salt culture medium.

[0035] Furthermore, during the culture process, a culture medium containing trace elements required by the microbial strains is added.

[0036] Furthermore, during the degradation process, the chemical structure of polyethylene plastic changes, and carbonyl, hydroxyl and carboxylic acid groups appear.

[0037] The fifth object of the present invention is to provide an application of the aforementioned strain and / or the aforementioned preparation product in the preparation of a degradation agent for degrading polyethylene plastic.

[0038] To achieve the above object, the present invention adopts the following technical solutions:

[0039] Use of the aforementioned strain and / or the aforementioned preparation product in the preparation of a degradation agent for degrading polyethylene plastic.

[0040] The beneficial effects of the present invention are:

[0041] 1. The present invention isolates and screens a strain that can effectively degrade polyethylene plastic from the intestinal fluid of the larvae of tobacco beetles (Lasioderma serricorne) that gnaw polyethylene plastic: Brevundimonas huaxiensis PEI LAB LA-17. The strain can use polyethylene plastic as the sole carbon source for growth and effectively degrade polyethylene. Currently, there is no method for treating polyethylene using the strain. The present invention provides a new strain resource for the biodegradation of polyethylene plastic mulch.

[0042] 2. The PEI LAB LA-17 of the present invention can effectively degrade polyethylene plastics. Scanning electron microscopy was used to observe that the surface of the plastic polyethylene was rough and had obvious cracks; Fourier transform infrared spectroscopy found that the chemical structure of the polyethylene plastic changed after degradation, indicating that the strain has a good degradation effect on polyethylene plastics. The present invention provides new resources and ideas for the treatment of polyethylene plastic waste in the environment, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is the colony morphology of PEI LAB LA-17;

[0044] Figure 2 This is the Gram staining identification result of PEI LAB LA-17;

[0045] Figure 3 This is the phylogeny of PEI LAB LA-17 based on 16S rDNA sequence;

[0046] Figure 4 This is the growth curve of PEI LAB LA-17 using polyethylene plastic film as carbon source;

[0047] Figure 5 This is a fluorescence image of bacterial activity detection of PEI LAB LA-17 on polyethylene plastic film;

[0048] Figure 6 This is a scanning electron microscope observation image of PEI LAB LA-17 on polyethylene plastic film;

[0049] Figure 7 This is a morphological feature diagram of polyethylene plastic after degradation by PEI LAB LA-17 under a scanning electron microscope; Figure 7 -A is the morphological characteristics of the control group; Figure 7 -B is the morphological characteristics of the PEI LAB LA-17 strain treatment group;

[0050] Figure 8 This is the infrared spectrum of the structure of polyethylene plastic after degradation in PEI LAB LA-17. DETAILED DESCRIPTION

[0051] The technical solution of the present invention will be further described clearly and completely in conjunction with specific embodiments below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present invention.

[0052] In an embodiment of the present invention, a strain PEI LAB LA-17 that can degrade polyethylene plastic is provided, which is classified and named Brevundimonas huaxiensis, and was deposited in the General Microbiological Center of China National Microbiological Culture Collection Committee on September 26, 2024. The deposit address is No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, China, and the deposit number is CGMCC No. 32083.

[0053] In the embodiment of the present invention, the sequence information involved is shown in Table 1.

[0054] Table 1. List of sequence information

[0055]

[0056] Example 1. Enrichment, separation, screening and identification of PEI LAB LA-17

[0057] (1) Enrichment, separation and screening

[0058] Disinfect the larvae of tobacco beetles gnawing on plastic until they are clean. Pull out the intestines after dissection under sterile conditions, remove the intestinal fluid, and prepare an intestinal bacterial suspension. Add the prepared intestinal bacterial suspension to 50 ml of sterilized carbon-free mineral salt liquid culture medium into a conical flask, and add a sterile polyethylene film (2×2 cm 2 ), and then cultured at 30°C and 150rpm for 30 days. Take a small amount of culture solution and place it on TSA solid culture medium for plate coating. After obvious colonies grow on the plate, observe the size, color, and morphology of the colonies, and mark the strains with different morphologies. Then purify and number the isolated bacteria by TSA solid culture medium streaking method, and store them in a 4°C refrigerator for later use. Then, by adding a carbon-free mineral salt liquid culture medium with polyethylene film as the only carbon source, measuring OD600 can indicate that strains are growing in the culture medium, and finally screen out a bacterium that can efficiently degrade polyethylene plastics, marked as PEI LAB LA-17.

[0059] Among them, the formula of the carbon-free mineral salt liquid culture medium is: K2HPO4·3H2O 0.7g / L, KH2PO4, 0.7g / L, NH4NO31.0g / L, MgSO4·7H2O 0.5g / L, NaCl 0.005g / L, FeSO4·7H2O 0.002g / L, ZnSO4·7H2O0.002g / L, MnSO4·H2O 0.001g / L;

[0060] TSA medium: 6 g tryptone, 2 g soy peptone, 2 g sodium chloride, 400 mL distilled water, and 6 g agar powder added to the solid medium.

[0061] (2) Colony characteristics and colony morphology

[0062] The colony morphology of PEI LAB LA-17 is as follows Figure 1 As shown in the figure, the PEI LAB LA-17 strain is light yellow, round, protruding, viscous and opaque. After being stained by Gram staining, the bacteria can be observed under an oil microscope. It is a Gram-negative bacterium with a short rod shape. For details, see Figure 2 .

[0063] (3) Physiological and biochemical characteristics

[0064] The strain PEI LAB LA-17V.P test was negative, the glucose acid production test was positive, the CIT citrate test was negative, the IND indole test was negative, the GEL gelatin liquefaction test was negative, and the H2S hydrogen sulfide test was negative.

[0065] (4) Molecular Biological Identification

[0066] 1) Use Tiangen DNA extraction kit according to the manufacturer's instructions to extract bacterial DNA of the target strain.

[0067] 2) PCR amplification was performed using 16SrDNA sequence primers 27F and 1492R as amplification primers. The nucleotide sequence of 27F is shown in SEQ ID NO:2, and the nucleotide sequence of 1492R is shown in SEQ ID NO:3. PCR amplification was performed in a 20 μL reaction system, with 1 μL of template DNA, 10 μL of 2×Mix, 1 μL of primer 27F, 1 μL of primer 1492R, and 7 μL of ddH2O. The conditions for PCR amplification included: the amplification program was pre-denaturation at 95°C for 4 min; denaturation at 95°C for 1 min, annealing at 55°C for 1 min, extension at 72°C for 1 min, and 35 cycles; finally, extension at 72°C for 10 min and storage at 4°C.

[0068] 3) The amplified products were detected by electrophoresis, and the amplified products of the strains were sent to Shanghai Shenggong Biotechnology Co., Ltd. for sequencing. The obtained sequences were compared with the existing sequences in the NCBI database for BLAST analysis, and strains with similar homology were selected to construct a phylogenetic tree using MEGA 11 software.

[0069] The results showed that PEI LAB LA-17 was on the same branch as Brevundimonas huaxiensis, and its 16S rDNA sequence was 99.41% similar to Brevundimonas huaxiensis strain 090558 (NR_181184.1). Combining colony morphology, physiological and biochemical characteristics and 16S rDNA sequence analysis, a phylogenetic tree was constructed to determine its genus and species, and it was preliminarily identified as Brevundimonas huaxiensis. Figure 3 The nucleotide sequence of Brevundimonas sinensis 16S rDNA is shown in SEQ ID NO:1.

[0070] Example 2. Degradation effect of PEI LAB LA-17 on polyethylene plastic film

[0071] In order to evaluate the application of PEI LAB LA-17 in the biodegradation of polyethylene plastics, this example selected common polyethylene plastic films for degradation effect determination. PEI LAB LA-17 was inoculated into LB medium and cultured until the logarithmic growth phase. The polyethylene film was cut into 2×2 cm 2 , sterilize with 75% ethanol for 2 hours after weighing, and then use sterile airflow in the clean bench to evaporate the ethanol on the surface to complete surface sterilization. Add 100 ml of carbon-free mineral salt liquid culture medium to the conical flask, add 3 pieces of surface-sterilized polyethylene film, and inoculate the above-mentioned PEI LAB LA-17 culture solution. Place the conical flask in a constant temperature shaking incubator at 30°C and 150r / min for 30 days, during which the growth curve of PEI LAB LA-17 is measured when polyethylene (PE) plastic is the only carbon source. After 90 days, samples were taken to measure the colonization ability of PEI LAB LA-17 in polyethylene film and bacterial viability test (live bacteria / dead bacteria staining kit), as well as the changes in the surface morphology and functional groups of polyethylene film caused by PEI LAB LA-17. The details are as follows:

[0072] (1) Growth of PEI LAB LA-17 strain in polyethylene plastic

[0073] Method: Sterilized polyethylene plastic and PEI LAB LA-17 bacterial solution were added into 50 mL of carbon-free mineral salt liquid culture medium. The control group was treated with no polyethylene film. The OD600 nm of the bacterial solution was recorded at 1d, 3d, 5d, 7d, 14d, 21d and 30d respectively.

[0074] Results: Figure 4As shown, the PEI LAB LA-17 strain showed significant growth in polyethylene plastic culture medium. From the 3rd day to the 7th day, OD600 increased from 0.057 to 0.071, and the strain reached the maximum OD600. After 14 days to 30 days, the bacterial growth rate decreased, and OD600 dropped from 0.067 to 0.061, indicating that the strain has ended the exponential growth phase and has just entered the stable phase.

[0075] (2) Bacterial activity detection

[0076] Methods: The PEI LAB LA-17 strain was cultured in a medium with polyethylene plastic as the sole carbon source for 90 days, and two dyes were used to stain the bacteria on the polyethylene plastic for bacterial viability detection. NucGreen dyed the bacteria green, representing live bacteria, and EthD-III dyed the bacteria red, representing dead bacteria.

[0077] Results: Figure 5 As shown, the PEI LAB LA-17 strain on polyethylene plastic was mostly active after 90 days of cultivation.

[0078] (3) Determination of bacterial biofilm on polyethylene plastic surface

[0079] Method: Rinse the excess culture medium on the polyethylene plastic surface with sterile water, fix it with 2.5% glutaraldehyde for 2 hours, then dehydrate it with a series of ethanol concentrations in gradient, each time for 15 minutes, and then replace it with tert-butanol twice, each time for 30 minutes. After fixation and gold spraying, observe its microscopic morphology under a scanning electron microscope.

[0080] Results: Figure 6 As shown, after 90 days, the surface of untreated (control CK) polyethylene plastic was smooth and no microorganisms were attached. After adding PEI LAB LA-17 strain, the polyethylene film showed adhesion and bacterial colonization was observed. The above results show that PEI LAB LA-17 strain can adapt to the living environment with polyethylene as the carbon source and can grow normally.

[0081] (4) Determination of surface changes of polyethylene plastics

[0082] Methods: First, remove the biofilm, wash the polyethylene plastic with 2% SDS solution for 2 hours, ultrasonicate for 15 minutes to remove the biofilm on the surface, and then wash it with sterile water for 3 times. Place the washed polyethylene plastic in a dryer and dry it for 48 hours. Observe the surface morphology of the treated samples under an optical microscope. Observe the changes of the surface morphology of polyethylene plastic by PEI LAB LA-17 strain under a scanning electron microscope.

[0083] Results: Figure 7As shown, after 90 days of cultivation, it was observed under a scanning electron microscope that the polyethylene plastic in the PEI LAB LA-17 strain treatment group had a rough surface and clear cracks compared with the control group, while the surface of the control group was relatively smooth and had no cracks.

[0084] (5) Determination of functional groups on the surface of polyethylene plastics

[0085] Method: After the polyethylene film with biofilm removed was naturally dried, it was measured using a Fourier transform infrared spectrometer with a scanning wavelength range of 500-4000cm -1 , resolution 4cm -1 , scan times 32 times.

[0086] Results: Figure 8 As shown, at 500~4000cm -1 The Fourier transform infrared spectra showed that compared with the control group, the PEI LAB LA-17 strain caused the polyethylene film to have a high density at 1000-1500 cm -1 A new CO characteristic peak was generated at 1500-1670 cm -1 A new C=C characteristic peak was generated at 1650-1750cm -1 A new C=O characteristic peak was generated at 3200-3600 cm -1 A new -OH characteristic peak was generated. Studies have shown that the appearance of carbonyl, hydroxyl and carboxylic acid groups is considered to be a preliminary and indispensable step in the oxidation and biodegradation of plastics. The appearance of CO, C=O and -OH is a basic sign of biodegradation of microplastics, indicating that microplastics have undergone oxidative degradation.

[0087] In summary, the present invention isolates and screens a polyethylene plastic degrading bacterium from insects that gnaw polyethylene plastics, and names it Brevundimonas huaxiensis PEI LAB LA-17, which can use polyethylene plastics as the sole carbon source for growth. The PEI LAB LA-17 strain acts on polyethylene plastics, which can induce hydrolysis and cause molecular chain breakage. The bacterium has a good degradation effect on polyethylene film, and shows great application prospects in degrading polyethylene plastics in the environment, providing new resources and ideas for the treatment of microplastic waste in the environment.

Claims

1. A strain capable of degrading polyethylene plastics, characterized in that: The strain is PEI LAB LA-17, which is classified and named Brevundimonas huaxiensis. It was deposited in the General Microbiology Center of China National Microbiological Culture Collection Administration on September 26, 2024, with the deposit number CGMCC No.32083.

2. The strain according to claim 1, characterized in that The nucleotide sequence of 16S rDNA of the strain is shown in SEQ ID NO:

1.

3. A preparation product for degrading polyethylene plastics, characterized in that: The preparation product uses the strain described in any one of claims 1 to 2 as an active ingredient.

4. A method for separating and screening the strain according to any one of claims 1 to 2, characterized in that: The steps include: 1) Insects that chew polyethylene plastics are used as the source of bacteria, and a culture medium with polyethylene plastics as the only carbon source is used for enrichment culture to obtain a culture solution containing plastic-degradable microorganisms; 2) Purifying the culture fluid obtained in step 1) by solid TSA medium streaking method; then adding medium with polyethylene plastic as the sole carbon source for further culturing, and screening out polyethylene degrading bacteria PEI LAB LA-17.

5. The method according to claim 4, characterized in that The insects that gnaw on polyethylene plastic are tobacco beetle larvae.

6. The method according to claim 4, characterized in that In step 1), the culture conditions are: constant temperature shaking culture at 25-35°C and 140-160r / min for 24-48 days.

7. A method for degrading polyethylene plastic using the strain according to any one of claims 1 to 2, characterized in that: The strain described in any one of claims 1 to 2 is co-cultured with polyethylene plastic to degrade the polyethylene plastic; the strain grows with polyethylene as the sole carbon source.

8. The method according to claim 7, characterized in that The strain is cultured together with polyethylene plastic in an inorganic salt medium.

9. The method according to claim 7, characterized in that: During the degradation process, the chemical structure of polyethylene plastic changes, and carbon, hydroxyl and carboxylic acid groups appear.

10. Use of the strain according to any one of claims 1 to 2 and / or the preparation product according to claim 3 in the preparation of a degradation agent for degrading polyethylene plastics.

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