Bacterium with activity of degrading polyethylene plastic and application thereof

Abstract

The invention provides a bacterium with polyethylene plastic degradation activity and application thereof, and belongs to the technical field of polyethylene plastic degradation. The bacterium with the activity of degrading the polyethylene plastic, provided by the invention, comprises at least one of pseudomonas putida ZSA123 with the preservation number of CGMCC (China General Microbiological Culture Collection Center) No.34958 and enterobacter hormaechei LBA140 with the preservation number of CGMCC No.34957. The bacterium provided by the invention can obviously reduce the load, tensile stress and fracture displacement rate of a polyethylene plastic film, and when the bacterium is used for degrading polyethylene plastic, a relatively high weight loss rate can be achieved while the degradation time is shortened, and the degradation rate of the bacterium on the polyethylene plastic is far higher than that of an existing strain in the field.

Description

Technical Field

[0001] The invention belongs to the technical field of polyethylene plastic degradation, and particularly relates to bacteria with polyethylene plastic degradation activity and application thereof. Background Art

[0002] Plastic waste has poor natural degradation and accumulates in freshwater, marine, and terrestrial environments. Larger plastics typically degrade and break down in some way, forming smaller plastic fragments. Plastics exposed to sunlight undergo photooxidative degradation under ultraviolet radiation, and after a brief period of natural degradation, they mostly exist as microplastics. Under natural conditions, microplastics can further decompose into "nanoplastics" less than 100nm in size. As an emerging pollutant, micro- and nanoscale plastics (NPs) pose a potential risk to the environment and human health.

[0003] During the agricultural production process, polyethylene (PE) mulch becomes a long-term residue in the soil due to its difficult-to-degrade nature. Studies have shown that the content of microplastics accumulated in agricultural soil is already much higher than that in the ocean. The residual mulch in the soil of the farmland system not only hinders the normal growth of crops, but also causes significant damage to the ecological environment. According to WTO data, tiny particles of 9 types of plastics were detected in human stool samples from many countries, among which PE had the highest content. This means that PE microplastics have entered the human body and accumulated, which may cause irreversible damage to multiple organs of the human body. Therefore, discovering microbial resources with the ability to degrade PE and exploring its biodegradation potential are of great significance for controlling "white pollution" and protecting the agricultural ecological environment.

[0004] As research deepens, people are paying more and more attention to the potential of microorganisms to degrade PE. Biodegradation strategies are very likely to become one of the effective ways to reduce agricultural "white pollution" and provide valuable bacterial resources for the development of efficient bacterial agents for degrading agricultural film residues. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a bacterium having significant activity in degrading polyethylene plastic.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a bacterium with the activity of degrading polyethylene plastic, comprising at least one of Pseudomonas putida ZSA123 and Enterobacter hormaechei LBA140; the Pseudomonas putida ZSA123 has a preservation number of CGMCC No. 34958, and is classified as Pseudomonas putida; the Enterobacter hormaechei LBA140 has a preservation number of CGMCC No. 34957, and is classified as Enterobacter hormaechei.

[0008] The present invention also provides a bacterial agent with the activity of degrading polyethylene plastic, comprising at least one of the culture solution of Pseudomonas putida ZSA123 and the culture solution of Enterobacter hallii LBA140.

[0009] Preferably, the method for preparing the culture solution of Pseudomonas putida ZSA123 comprises the following steps: inoculating Pseudomonas putida ZSA123 into LB liquid culture medium and culturing at 25°C to 35°C.

[0010] Preferably, the method for preparing the culture solution of Enterobacter hallii LBA140 comprises the following steps: inoculating Enterobacter hallii LBA140 into LB liquid culture medium and culturing at 25°C to 35°C.

[0011] Preferably, the culture time is more than 10 days.

[0012] The present invention also provides the use of the above bacteria or the above bacterial agent in degrading polyethylene plastics.

[0013] The present invention also provides a method for degrading polyethylene plastics, comprising the following steps: inoculating the above bacteria into a culture solution containing a substance to be degraded, and culturing.

[0014] Preferably, the culture medium includes LB liquid culture medium.

[0015] Preferably, the culture temperature is 25°C to 35°C.

[0016] The present invention also provides a method for degrading polyethylene plastics, comprising the following steps: mixing a substance to be degraded with the above-mentioned bacterial agent and co-culturing the mixture.

[0017] Beneficial effects of the present invention:

[0018] The bacteria provided by the present invention can significantly reduce the load, tensile stress and fracture displacement rate of polyethylene plastic film. When the bacteria of the present invention are used to degrade polyethylene plastic, a high weight loss rate can be achieved while shortening the degradation time, and the degradation rate of polyethylene plastic is far higher than that of existing strains in the field.

[0019] Preservation Instructions

[0020] The classification name of the Pseudomonas putida ZSA123 of the present invention is Pseudomonas putida, and it is deposited in the General Microbiology Center of the China Culture Collection Administration Committee, located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, with the deposit number CGMCC No. 34958 and the deposit date being June 20, 2025.

[0021] The classification name of the Enterobacter hormaechei LBA140 of the present invention is Enterobacter hormaechei, and it is deposited in the General Microbiology Center of the China Culture Collection Administration Committee, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, with a deposit number of CGMCC No. 34957 and a deposit date of June 20, 2025. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Photos of the greater wax moth before (left) and after (right) feeding on PE film;

[0023] Figure 2 The comparative analysis results of Fourier transform infrared spectra of residual polymers in the feces of greater wax moth larvae and the control PE sample, where the arrows indicate the characteristic peaks of degradation;

[0024] Figure 3 Comparison of thermogravimetric analysis curves of feces of larvae fed on plastic and control PE samples, where A is the result of feces sample of larvae fed only on PE film, B is the result of feces sample of larvae fed on PE film and wheat bran, C is the result of feces sample of larvae fed only on wheat bran, and D is the result of untreated PE film;

[0025] Figure 4 is the change in molecular weight (Mw) of residual polymers and polyethylene (PE) in fecal samples determined by gel permeation chromatography (GPC), where A is the result of fecal samples of larvae fed only with PE film, B is the result of fecal samples of larvae fed with PE film and wheat bran, C is the result of fecal samples of larvae fed only with wheat bran, and D is the result of untreated PE film;

[0026] Figure 5 The growth curves of the two dominant degrading bacteria over 30 days;

[0027] Figure 6 This is the degradation change diagram of polyethylene film by two dominant degrading bacteria over 30 days;

[0028] Figure 7 These are the surface microscopic changes under a scanning electron microscope after 30 days of co-culture of the membrane with the inoculated strains. The left picture shows the results of strain ZSA123, and the right picture shows the results of strain LBA140. DETAILED DESCRIPTION

[0029] The present invention provides a bacterium with the activity of degrading polyethylene plastic, comprising at least one of Pseudomonas putida ZSA123 and Enterobacter hormaechei LBA140; the Pseudomonas putida ZSA123 has a preservation number of CGMCC No. 34958, and is classified as Pseudomonas putida; the Enterobacter hormaechei LBA140 has a preservation number of CGMCC No. 34957, and is classified as Enterobacter hormaechei.

[0030] The bacteria described in the present invention are screened and isolated from the intestines of Galleria mellonella larvae that gnaw on plastic. The strains isolated and screened were subjected to phylogenetic tree analysis based on 16S rDNA sequences, morphological characteristics were analyzed using Gram staining analysis and electron scanning microscope imaging, and physiological characteristics were analyzed using API kit (50CHB) analysis and enzyme activity analysis. The results showed that ZSA123 belonged to Pseudomonas putida and LBA140 belonged to Enterobacter hallii.

[0031] Experiments have confirmed that inoculating polyethylene (PE) films with either Pseudomonas putida ZSA123 or Enterobacter hallii LBA140 significantly reduced the load, tensile stress, and fracture displacement of the PE films compared to uninoculated PE films. The PE films treated with Pseudomonas putida ZSA123 and Enterobacter hallii LBA140 showed weight loss rates of 28.6% and 25.0%, respectively, after 30 days, with bacterial growth positively correlated with the degree of degradation. The weight loss rates achieved by the strains of the present invention exceed those previously reported in studies of polyethylene plastic degradation using strains of the same genus or species. For example, Kang et al. (2023) found that Enterobacter hallii, derived from Tenebrio molitor larvae, degraded polystyrene film at a rate of (2.76±0.22)% under static anaerobic conditions. An earlier study by Kyaw et al. (2012) showed significant differences in the efficiency of different strains of the genus Pseudomonas: Pseudomonas aeruginosa caused LDPE film (NTUC plastic bags) to lose 20% of its weight within 120 days, while the degradation rates of Pseudomonas aeruginosa and Pseudomonas putida, both of the same genus, were only 11% and 9%, respectively. Overall, although microbial degradation efficiency is affected by the type of plastic polymer, its chemical properties, and culture conditions, the strain isolated from the larvae of the greater wax moth exhibited a relatively higher degradation rate, indicating its potential for application in the bioremediation of plastic waste.

[0032] In some embodiments of the present invention, the bacteria having the activity of degrading polyethylene plastic is Pseudomonas putida ZSA123, or Enterobacter hallii LBA140, or a combination of Pseudomonas putida ZSA123 and Enterobacter hallii LBA140.

[0033] The present invention also provides a bacterial agent with the activity of degrading polyethylene plastic, comprising at least one of the culture solution of Pseudomonas putida ZSA123 and the culture solution of Enterobacter hallii LBA140.

[0034] In the present invention, the method for preparing the culture broth of Pseudomonas putida ZSA123 preferably comprises the following steps: inoculating Pseudomonas putida ZSA123 into LB liquid culture medium and culturing at 25°C to 35°C. The present invention does not particularly limit the specific source of the LB liquid culture medium; conventional commercially available products in the art can be used. In the present invention, the culture temperature is preferably 28°C to 32°C, more preferably 30°C to 31°C; the culture duration is preferably at least 10 days, more preferably 10 to 60 days, and even more preferably 20 to 50 days.

[0035] In the present invention, the method for preparing the culture broth of Enterobacter hallii LBA140 preferably comprises the following steps: inoculating Enterobacter hallii LBA140 into LB liquid culture medium and culturing at 25°C to 35°C. The present invention does not particularly limit the specific source of the LB liquid culture medium; conventional commercially available products in the art can be used. In the present invention, the culture temperature is preferably 28°C to 32°C, more preferably 30°C to 31°C; the culture duration is preferably 10 days or more, more preferably 10 days to 60 days, and even more preferably 20 days to 50 days.

[0036] The bacterial inoculum provided by the present invention is capable of degrading polyethylene plastic and converting it into low-molecular-weight substances. Given that the growth of the strain is positively correlated with the degree of degradation, adjusting the incubation temperature and time can further enhance the degradation performance of polyethylene plastic, effectively improving the effectiveness, productivity, and selectivity of polyethylene plastic regeneration.

[0037] The present invention also provides the use of the above bacteria or the above bacterial agent in degrading polyethylene plastics.

[0038] The present invention also provides a method for degrading polyethylene plastics, comprising the following steps: inoculating the above bacteria into a culture solution containing a substance to be degraded, and culturing.

[0039] In the present invention, the culture medium preferably comprises LB liquid medium. In the present invention, the culture temperature is preferably 25°C to 35°C, more preferably 27°C to 34°C, and even more preferably 39°C to 32°C. In the present invention, the material to be degraded preferably comprises polyethylene plastic or waste containing polyethylene plastic. In the method for degrading polyethylene plastic of the present invention, the culture duration is preferably 10 days or longer.

[0040] The present invention also provides a method for degrading polyethylene plastic, comprising the steps of mixing a substance to be degraded with the aforementioned bacterial agent and co-culturing the mixture. In the present invention, the incubation temperature is preferably 25°C to 35°C, more preferably 27°C to 34°C, and even more preferably 39°C to 32°C. In the present invention, the substance to be degraded preferably comprises polyethylene plastic or waste containing polyethylene plastic. In the method for degrading polyethylene plastic of the present invention, the incubation time is preferably at least 10 days.

[0041] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0042] In the following examples, unless otherwise specified, all methods are conventional.

[0043] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0044] Example 1

[0045] Isolation, screening and identification of bacteria from the intestines of greater wax moth larvae:

[0046] (1) Acclimation of wax moth larvae

[0047] A total of 360 uniformly shaped wax moth larvae were selected and, after being starved for 2 days, randomly divided into an experimental group and a control group. The experimental group was further divided into two subgroups: one subgroup was fed only polyethylene (PE) film, and the other subgroup was fed a mixture of PE film and wheat bran (the weight ratio of PE film to wheat bran was 7:3). Each group had three replicates. During the experiment, the larvae in the control group were fed an amount of wheat bran equivalent to 1.2 times their body weight and sprayed with distilled water daily. They were placed in an intelligent climate chamber at 35°C and 60% humidity for rearing. The experiment lasted for 15 days, and the weight, number of surviving larvae, and number of pupae were recorded every 3 days, and wheat bran was supplemented as needed.

[0048] After 15 days of culture, there were many erosion holes on the surface of the PE membrane (see Figure 1), demonstrating that G. mellonella can ingest PE. In the subgroup fed only with PE film, the initial average weight of the PE film sheets was 14.80 g. After 15 days of incubation, the average weight of the PE film sheets decreased by 0.50 g. This weight loss steadily increased with increasing incubation time, indicating that G. mellonella larvae ingesting PE film sheets is not a temporary phenomenon. After an additional 10 days of incubation, the weight of G. mellonella larvae in the experimental group fed only with PE film increased significantly, indicating that acclimation effectively activated the PE-degrading microorganisms in the intestine.

[0049] (2) Detection and analysis of components in the excreta of greater wax moth larvae

[0050] The components of the excreta of the greater wax moth larvae of different groups (PE frass group: fed with PE film only, PE+branfrass group: fed with PE film + wheat bran, bran frass group: fed with wheat bran only) were detected by infrared spectroscopy (FT-IR). The PE control group (untreated PE film) was also detected by infrared spectroscopy (FT-IR). The results are shown in the figure. Figure 2 As shown, in stool samples, 1623 cm -1 The absorption peak that appears at is located in the carbonyl (C=O) stretching vibration region (1750cm -1 to 1680cm -1 ), indicating the presence of significant carbonyl (C=O) functional groups. -1 to 1400cm -1 Characteristic peaks were also detected in the alcohol group (R-OH) bending vibration region of the PE sample. In contrast, the control PE sample did not show the carbonyl characteristic peak, and the peak shape of the alcohol group bending vibration region was narrower and the intensity was lower. In addition, the fecal samples of larvae that ingested PE showed a peak at 3000-3500 cm -1 The band showed a significantly broadened, high-intensity absorption peak, indicating that it has stronger hydrophilic characteristics than the control PE sample. These results confirm the formation of oxygen-containing functional groups (carbonyl and hydroxyl groups), indicating that microorganisms in the larval gut can degrade PE.

[0051] Thermogravimetric analysis (TGA) showed that Figure 3 As shown in the figure, insect feces gradually lose weight as the temperature rises, accompanied by multiple energy transition points. These changes indicate that insect feces have undergone multiple pyrolysis processes. The weight loss of PE, on the other hand, shows a single characteristic. At 490°C, PE reaches its energy peak, and the weight of the material decreases by more than 90%. Insect feces show a richer weight loss pattern, proving that in addition to plastic components, insect feces also contain other substances. In the stage where the weight loss rate of plastics decreases significantly, the weight loss rate of insect feces decreases significantly, indicating that there is less plastic content in insect feces.

[0052] The molecular weight of wax moth feces and PE of different groups was determined by gel permeation chromatography (GPC). Figure 4 As shown, the molecular weight distribution of insect feces exhibited a uniform leftward shift relative to the PE curve. The shift was most pronounced in the group fed only PE, with a relative shift of 3139 relative to the PE raw material. Further data analysis revealed that the weight-average molecular weight of insect feces was 2671, while PE was as high as 5427, 2.03 times the weight of insect feces. This phenomenon is hypothesized to be due to the selective mineralization of high-molecular-weight polyethylene by microorganisms in the gut of the Greater Glyptostroboides moth larvae, indicating that these microorganisms have the ability to degrade PE.

[0053] (3) Evaluation of the degradation performance of PE-degrading strains in the intestines of G. mellonella larvae

[0054] Ten larvae were randomly selected from each group and soaked in a 75% ethanol solution and sterile saline for 1 minute. The larvae were then placed on absorbent paper to remove the surface saline. The larvae were then transferred to a sterile tray, and the entire intestinal tract was removed with a scalpel. The intestinal bacterial suspension was then ground with an appropriate amount of sterile NaCl solution to obtain the intestinal bacterial suspension. Glycerol was added proportionally and the suspension was stored at -20°C until further use. 0.5 mL of the intestinal fluid was then added to flasks containing 100 mL of LB liquid medium and cultured in a shaker at 35°C and 160 rpm for 3 days. 5 mL of the culture medium enriched with intestinal flora of the greater wax moth larvae was inoculated into an inorganic salt medium MSM (ingredients: 0.2 g / LMgSO4·7H2O, 1.0 g / LNH4NO3, 0.01 g / LCaCl2, 0.5 g / LKH2PO4, 1.5 g / LNa2HPO4, pH 7.2) containing 1% (w / v) sterilized PE powder (particle size ≤100 μm). The inoculated culture system was aerobically cultured at 30°C and 160 rpm under shaking conditions for 10 days.

[0055] Take 1mL of culture medium and divide it into test tubes, dilute it with 9mL of sterile water to make 10 -1 The suspension was diluted serially to make 10 -2 , 10 -3 , 10 -4 , 10 -5 Suspensions of different concentrations. Spread 200 μL of each suspension onto LB medium, with three replicates per group. Incubate at 30°C for 2–3 days. After bacterial growth, select strains with distinct characteristics (morphology, size, and color) and purify them by streaking onto LB plates. Inoculate the purified strains onto slant culture medium. Repeat the isolation and purification process several times to obtain single colonies. Store at 4°C for later use.

[0056] The membrane pieces were numbered and weighed initially. After sterilization, they were added to the corresponding conical flasks. The strains were inoculated into LB liquid medium with the membrane pieces and cultured in a shaking incubator at 35°C and 150 rpm for 30 days. The OD of each culture medium was measured every 5 days. 600 The value is used as an indicator of the growth of the inoculated bacteria. Take out the membrane every 5 days, sterilize and clean it with anhydrous ethanol, rinse with sterile water and dry it, and then weigh it. Take out the PE membrane that has been inoculated with bacteria for 30 days, fix it with gold spray, and use SEM to observe the microscopic changes on the surface of the membrane. The membrane that has not been inoculated with degrading bacteria for 30 days is used as a control. Fourier transform infrared spectrometer is used to measure the changes in the surface chemical functional groups of the PE membrane. The scanning wavelength range is 1000~3500cm -1 , with a resolution of 4.0 cm -1 The load, tensile stress and fracture displacement rate of PE membranes inoculated with bacteria for 30 days and the blank control group were measured using an electronic universal testing machine at room temperature and a tensile speed of 50 mm / min.

[0057] According to the above method, 11 strains were selected and 200 μL of cell suspensions of different dilutions were evenly spread on the agar surface, and then covered with sterile PE film to evaluate the basic growth ability of the isolated bacteria on the culture medium. They were inoculated into the culture medium containing the PE film and co-cultured. The growth of the strains and the weight loss rate of the film were measured every 5 days. The results are as follows: Figure 5 and Figure 6 As shown in the figure, it was found that two strains ZSA123 (membrane No. 1, screened on LB culture medium plate) and LBA140 (membrane No. 6, screened on LB culture medium plate) had strong degradation ability. After 30 days of cultivation, the OD values ​​of strains ZSA123 and LBA140 were 600 The values ​​were 2.60 and 2.77 respectively (see Figure 5 At the same time, the weight loss rates of PE under the degradation of strains ZSA123 and LBA140 reached 30.76% and 28.22% respectively (p < 0.05) (see Figure 6 ).

[0058] The surface structure changes of PE membranes after co-culture with 11 different strains for 30 days were observed under SEM. All membranes showed roughness. Among them, membranes No. 1 (strain ZSA123) and No. 6 (strain LBA140) showed holes (see Figure 7 ), while the surface structure of the uninoculated control PE membrane remained unchanged under the same conditions.

[0059] During the 30-day degradation period, compared to the control group (uninoculated PE membrane, No. 12), the PE membranes treated with the two dominant bacteria (strains ZSA123 and LBA140) showed significant decreases in load, tensile stress, and fracture displacement rate (Table 1). This indicates that the degrading bacteria ZSA123 (membrane 1) and LBA140 (membrane 6) of the present invention have significant degradation efficiency on PE membranes and weaken the toughness of the PE membrane material.

[0060] Table 1 Load, tensile stress and fracture displacement rate of the membrane after 30 days of inoculation with dominant degrading bacteria

[0061] Diaphragm serial number Strain name Load (N) Tensile stress (MPa) Fracture displacement rate (%) Diaphragm 1 ZSA123 3.17804 12.43169 299.74015 Diaphragm 6 LBA140 5.45266 20.11756 383.66559 Diaphragm 12 Control 8.01524 36.28774 443.93826

[0062] (4) Molecular biological identification and phylogenetic analysis of the PE-degrading bacterial strains of the present invention

[0063] DNA was extracted from the bacterial suspension and amplified by PCR. Universal bacterial primers 27F and 1492R were used. The PCR reaction system (50 μL) included 2 μL each of the upstream and downstream primers (10 μmol / L), 2 μL DNA template, 25 μL TaqDNA MasterMix, and 21 μL ddH2O. Amplification conditions were as follows: 94°C for 5 min; 30 cycles of 94°C for 50 s, 55°C for 48 s, and 72°C for 1 min; and 72°C for 10 min. The product was detected by gel electrophoresis and sent to Sangon for sequencing. Sequencing results were aligned using BLAST; phylogenetic trees were constructed using the maximum likelihood analysis software RaxML-HPC2 in the CIPRES Science Gateway (http: / / www.phylo.org / ).

[0064] Sequence alignment analysis on the Blast platform revealed that the strain ZSA123, the most efficient PE film degrader, shared 95% homology with Pseudomonas putida, leading to the identification of ZSA123 as Pseudomonas putida. Phylogenetic analysis of the dominant strain LBA140 revealed 100% homology with Enterobacter hormaechei, leading to the identification of LBA140 as Enterobacter hormaechei.

[0065] Example 2

[0066] A bacterial agent with polyethylene plastic degradation activity is prepared by inoculating Pseudomonas putida ZSA123 obtained in Example 1 into LB liquid culture medium and culturing at 35° C. for 30 days.

[0067] Example 3

[0068] A bacterial agent with polyethylene plastic degradation activity is prepared by inoculating the Enterobacter hallii LBA140 obtained in Example 1 into LB liquid culture medium and culturing at 30° C. for more than 10 days.

[0069] Example 4

[0070] A method for degrading polyethylene plastics is as follows: after sterilizing the polyethylene plastics, the polyethylene plastics are placed in LB liquid culture medium, and then the Pseudomonas putida ZSA123 obtained in Example 1 is inoculated into the culture medium containing the polyethylene plastics, and cultured at 25° C. for more than 10 days.

[0071] Example 5

[0072] A method for degrading polyethylene plastics is as follows: after sterilizing the polyethylene plastics, the polyethylene plastics are placed in LB liquid culture medium, and then the Enterobacter hallii LBA140 obtained in Example 1 is inoculated into the culture medium containing the polyethylene plastics, and cultured at 35°C for 30 days.

[0073] Example 6

[0074] A method for degrading polyethylene plastics is as follows: after sterilizing the polyethylene plastics, the polyethylene plastics are placed in the bacterial agent obtained in Example 2 and cultured at 35°C.

[0075] Example 7

[0076] A method for degrading polyethylene plastics is as follows: after sterilizing the polyethylene plastics, the polyethylene plastics are placed in the bacterial agent obtained in Example 3 and cultured at 30°C.

[0077] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A bacterium having the activity of degrading polyethylene plastic, characterized in that: It includes at least one of Pseudomonas putida ZSA123 and Enterobacter hormaechei LBA140; the preservation number of Pseudomonas putida ZSA123 is CGMCC No.34958, and its classification name is Pseudomonas putida; the preservation number of Enterobacter hormaechei LBA140 is CGMCC No.34957, and its classification name is Enterobacter hormaechei.

2. A bacterial agent having the activity of degrading polyethylene plastic, characterized in that: The method comprises at least one of a culture solution of Pseudomonas putida ZSA123 and a culture solution of Enterobacter hallii LBA140.

3. The microbial agent according to claim 2, characterized in that The method for preparing the culture solution of Pseudomonas putida ZSA123 comprises the following steps: inoculating Pseudomonas putida ZSA123 into LB liquid culture medium and culturing at 25° C. to 35° C.

4. The microbial agent according to claim 2, characterized in that The method for preparing the culture solution of Enterobacter hallii LBA140 comprises the following steps: inoculating Enterobacter hallii LBA140 into LB liquid culture medium and culturing at 25° C. to 35° C.

5. The bacterial agent according to claim 3 or 4, characterized in that The culture time is more than 10 days.

6. Use of the bacterium according to claim 1 or the bacterial agent according to any one of claims 2 to 5 in degrading polyethylene plastics.

7. A method for degrading polyethylene plastic, characterized in that: The method comprises the following steps: inoculating the bacteria according to claim 1 into a culture solution containing a substance to be degraded, and culturing the solution.

8. The method according to claim 7, characterized in that The culture medium is LB liquid culture medium.

9. The method according to claim 7, characterized in that The culture temperature is 25°C to 35°C.

10. A method for degrading polyethylene plastic, characterized in that: The method comprises the following steps: mixing the substance to be degraded with the bacterial agent according to any one of claims 2 to 5, and co-culturing the mixture.

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