Bacterium DY-11 for degrading phenanthrene and benzopyrene in petroleum-contaminated soil and application of bacterium DY-11

Abstract

The invention discloses a bacterium DY-11 for degrading phenanthrene and benzopyrene in petroleum-contaminated soil and application of the bacterium DY-11. The bacterial strain is Achromobacter expander DY-11, and the preservation number of the bacterial strain is GDMCC No: 66005. Experiments prove that the strain DY-11 can respectively utilize phenanthrene and benzopyrene as carbon sources to degrade phenanthrene and benzopyrene, and after the strain DY-11 is cultured in inorganic salt culture solutions with the initial concentration of phenanthrene and benzopyrene being 50 mg.L <-1 > and 25 mg.L <-1 > respectively for 7 days, the degradation rates of phenanthrene and benzopyrene can reach 65% or above. Therefore, the DY-11 is a strain which can degrade phenanthrene and benzopyrene and has very strong tolerance to phenanthrene and benzopyrene, has strong adaptability to polycyclic aromatic hydrocarbons, and has better application potential in the aspect of bioremediation.

Description

Technical Field

[0001] The present invention relates to the field of microbial technology, and in particular to a bacterium DY-11 capable of degrading phenanthrene and benzopyrene in petroleum-contaminated soil and applications thereof. Background Art

[0002] With the rapid development of modern industrial processes, industrial pollution is increasingly affecting soil. Various persistent organic pollutants (POPs), such as polycyclic aromatic hydrocarbons (PAHs), are present in contaminated soil. PAHs are ubiquitous in the environment and continue to accumulate, attracting widespread attention. Human activities such as mining, agriculture, and high background levels in the soil have led to severe pollution and exceeding environmental standards for PAHs. PAHs are the primary pollutants in chemical parks and surrounding soils, as well as in oil and mining areas, and wastewater irrigation areas. Phenanthrene, a tricyclic aromatic hydrocarbon, is closely linked to the carcinogenicity of PAHs. Due to its unique chemical structure, phenanthrene has become a model compound for PAH research. Benzopyrene, a planar polycyclic structure composed of five fused benzene rings, is a potent carcinogen that binds to DNA in human cells to form adducts and induce genetic mutations. Due to their potential carcinogenic, teratogenic, mutagenic, and bioaccumulative properties, these two substances pose significant risks to the ecological environment and human health.

[0003] The natural degradation of toxic and hazardous organic pollutants in the environment primarily relies on the metabolism of relevant microorganisms. Bioremediation technology offers the advantages of low cost, high efficacy, and no secondary pollution, making it the most promising approach for remediating phenanthrene and benzo(a)pyrene pollution. Currently, only a few strains have been reported to degrade phenanthrene and benzo(a)pyrene, primarily including Virgibacillus, Chryseobacterium, and Bacillus. Because most microorganisms in the environment are unculturable, many, particularly those with specialized functions, cannot be isolated through pure culture. Therefore, identifying strains that can effectively degrade high concentrations of phenanthrene and benzo(a)pyrene has significant practical value and practical significance.

[0004] The strain reported in this study is Achromobacter anxifer, which can be isolated from various terrestrial and aquatic habitats. Currently, there are relatively few reports on the degradation of pollutants by Achromobacter anxifer, and no studies have been reported on the degradation of phenanthrene and benzopyrene by Achromobacter anxifer, either domestically or internationally. Summary of the Invention

[0005] The first object of the present invention is to provide an Achromobacter anxifer DY-11 strain, with a deposit number of GDMCC No: 66005.

[0006] In the present invention, a strain DY-11 (Achromobacter anxifer DY-11) was domesticated and isolated from petroleum-contaminated soil in Ningbo, Zhejiang Province. It uses high concentrations of phenanthrene and benzo[a]pyrene as carbon sources. The strain was identified and its growth characteristics and degradation properties of phenanthrene and benzo[a]pyrene were studied, providing a reference for bioremediation of PAHs-contaminated environments.

[0007] The second object of the present invention is to provide the use of the Achromobacter anxifer DY-11 in the degradation of polycyclic aromatic hydrocarbons.

[0008] Preferably, the polycyclic aromatic hydrocarbons include phenanthrene and benzopyrene.

[0009] Preferably, the bacterial suspension of Achromobacter anxifer DY-11 is applied to water or soil contaminated by polycyclic aromatic hydrocarbons.

[0010] The third object of the present invention is to provide the use of the Achromobacter anxifer DY-11 in the preparation of a polycyclic aromatic hydrocarbons-degrading bacterial agent.

[0011] A fourth object of the present invention is to provide a polycyclic aromatic hydrocarbon-degrading bacterial agent comprising the above-mentioned Achromobacter anxifer DY-11 or a pure culture thereof as an active ingredient.

[0012] The fifth object of the present invention is to provide the use of the Achromobacter anxifer DY-11 or bacterial agent in the bioremediation of polycyclic aromatic hydrocarbons-contaminated environments.

[0013] Preferably, the polycyclic aromatic hydrocarbons (PAHs) polluting the environment include PAHs polluting water and / or soil. The PAHs include phenanthrene and benzopyrene.

[0014] A sixth object of the present invention is to provide a method for degrading polycyclic aromatic hydrocarbons, which comprises applying the Achromobacter anxifer DY-11 or the bacterial agent to an environment contaminated by polycyclic aromatic hydrocarbons to degrade the polycyclic aromatic hydrocarbons.

[0015] The present invention domesticated and isolated a petroleum-contaminated soil strain DY-11 from Ningbo, Zhejiang Province, which uses phenanthrene and benzo[a]pyrene as carbon sources. Based on strain morphology, 16S rDNA gene sequencing analysis, and phylogenetic analysis, the strain was identified as Achromobacter anxifer DY-11. The optimal environmental conditions for DY-11 growth are a temperature of 28°C, a pH of 7, and no sodium chloride. 16S rDNA gene sequencing analysis of the strain showed that the closest relative to DY-11 was Achromobacter anxifer strain LMG 26857 (99.57%). DY-11 is able to utilize phenanthrene and benzo[a]pyrene as carbon sources, and can grow at initial concentrations of 50 mg / L phenanthrene and 50 mg / L benzo[a]pyrene, respectively. -1 and 25 mg·L -1 After culturing in inorganic salt culture medium for 7 days, the degradation rate can reach more than 65%. Therefore, this strain has good application potential in the bioremediation of polycyclic aromatic hydrocarbons.

[0016] Achromobacter anxifer DY-11 was deposited on March 12, 2025 in Guangdong Provincial Microbiological Culture Collection Center (GDMCC), address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou City, Guangdong Province, Postal Code: 510070, and the deposit number is: GDMCC No: 66005. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 These are the front and back views of strain DY-11 grown on LB solid medium for 12 hours.

[0018] Figure 2 This is the phylogenetic information of strain DY-11.

[0019] Figure 3 Shows the growth of strain DY-11 under different conditions.

[0020] Figure 4 is the degradation efficiency of strain DY-11 in high concentration phenanthrene and benzo[a]pyrene inorganic salt medium (the initial concentrations of phenanthrene and benzo[a]pyrene were 50 mg·L -1 and 25 mg·L -1 ). DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings and specific examples, but the examples do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0022] Example 1: Isolation and identification of Achromobacter anxifer DY-11

[0023] 1. Sample source

[0024] Soil samples were collected from a petroleum-contaminated soil in Ningbo, Zhejiang Province. They were acclimated for a long time using high concentrations of phenanthrene and benzo[a]pyrene as carbon sources, respectively. Through multiple screening, separation and purification, highly efficient phenanthrene and benzo[a]pyrene-degrading bacteria were obtained.

[0025] 2. Culture medium

[0026] 2.1 Inorganic salt culture medium

[0027] Inorganic salt culture medium is used for enrichment and culturing of microorganisms in samples and for phenanthrene and benzopyrene degradation experiments under pure bacterial conditions. The medium formula is shown in Table 1. It is prepared by adding all ingredients to water, stirring, and sterilizing.

[0028] Table 1 Inorganic salt culture medium formula

[0029]

[0030]

[0031] 2.2 Nutrient medium

[0032] Nutrient media are used for the isolation, purification, preservation, and activation of bacteria for routine microbial cultivation. The types and compositions of liquid nutrient media used in this experiment are shown in Table 2. If solid media are required, simply add 1.5-2% agar powder to the original medium formula. Unless otherwise specified for strain culture conditions, adjust the medium pH to 7. Preparation is by adding all ingredients to water, stirring, and sterilizing.

[0033] Table 2 Luria-Bertani medium (LB) components

[0034]

[0035] 3. Domestication, screening and isolation of strains

[0036] The collected contaminated soil was added to the enrichment medium (inorganic salt medium) at a concentration of 50 mg·L -1 The concentration of phenanthrene is 25 mg·L -1 Benzopyrene was used as the degradation substrate and cultured in a 28°C incubator with shaking in the dark. The strain was acclimated using an inorganic salt medium containing either phenanthrene or benzopyrene as the carbon source, with each acclimation period lasting 7 days. A 10% inoculum was transferred to fresh enrichment medium using the same culture system and the enrichment process repeated three times.

[0037] The fourth-generation enrichment culture sample obtained above was spread and separated using the dilution plating method, and the sample was separated using a nutrient medium. The spread sample was incubated at the original culture temperature. After approximately 48 hours, distinct single colonies formed on the culture medium surface. Several distinct single colonies were selected based on their morphology, size, color, transparency, and other characteristics, and streak-purified on nutrient medium plates and cultured. If single colonies with different characteristics were still observed on the streak-purified plates, they were streaked again until only single colonies with the same characteristics were observed on the same plate. The experiment screened and identified a strain, DY-11, that was highly effective in degrading both phenanthrene and benzopyrene. The purified single colonies were cultured in the corresponding liquid nutrient medium until the logarithmic phase. The bacterial suspension was mixed with sterile glycerol and aliquoted into sterile 2 mL cryovials (glycerol concentration: 15%) for long-term storage at -80°C.

[0038] 4. Strain identification

[0039] 4.1 Morphological characteristics

[0040] DY-11 is a bacterium isolated from a petroleum-contaminated soil in Ningbo, Zhejiang Province. After activation, it can form white, round, smooth, slightly convex, opaque, non-spore, and non-flagellated colonies with a diameter of 1.5 mm after growing on LB medium plates under aerobic conditions at 28°C for 12 hours. Figure 1 ).

[0041] 4.2 Molecular biological characteristics

[0042] Molecular biological characterization primarily involves sequencing and phylogenetic tree construction. Before sequencing and phylogenetic tree construction, bacterial DNA must be extracted (the bacterial genomic DNA rapid extraction kit used in the experiment was from Beijing Adlai Biotechnology Co., Ltd.). To study bacterial taxonomy, it is often necessary to amplify the 16S rRNA gene and construct a phylogenetic tree. The amplified gene is a segment of DNA that encodes rRNA in prokaryotes. Because of its high conservation, specificity, and relatively suitable sequence length, it is often used to detect and identify bacteria.

[0043] Polymerase chain reaction (PCR) is mainly used to amplify different gene fragments. PCR requires different primers (27F and 1492R; Baker et al., 2003). The PCR amplification reaction system is: 10× buffer 2.5μL, Mg 2+1.5 μL of dNTP (25 mmol / L), 0.3 μL of dNTP (25 mmol / L), 0.5 μL of forward primer (10 mmol / L), 0.5 μL of reverse primer (10 mmol / L), 0.25 μL of Taq enzyme, 0.1 μL of DNA template, and 19.35 μL of deionized water. PCR amplification reaction conditions: denaturation at 95°C, annealing at 55°C, and extension at 72°C for 30 cycles, followed by extension at 72°C for 10 min. After completion of the PCR reaction, the tube was stored at 4°C. After amplifying the desired gene, a gel block is prepared using 0.75-1% agarose and the nucleic acid dye GelRed. The PCR product and DNA markers of various lengths are added to the gel block and placed in an electrophoresis apparatus filled with TBE (Tris boric acid) buffer. The apparatus is operated at a constant voltage for 20 minutes, then removed and observed under a 300nm UV lamp to confirm successful PCR amplification. Successfully amplified PCR products are then sent to BGI Genomics for sequencing using the same primers as the amplification primers.

[0044] The bacterial 16s rRNA gene sequence obtained by sequencing was uploaded to EzTaxon-e

[0045] The website (http: / / eztaxon-e.ezbiocloud.net / ) compares the submitted sequence with the 16S rRNA gene sequences of representative strains of recognized species to determine sequence similarity. Based on the sequence alignment results, the corresponding representative strain can be selected as the model strain for the experimental isolate. The 16S rRNA gene sequence of the model strain can also be obtained, allowing phylogenetic analysis to demonstrate differences between the model strain and the experimental isolate, thereby identifying the isolate. Phylogenetic trees are constructed using the MEGA 5.05 program, typically using the neighbor-joining, minimum evolution, and maximum parsimony methods. The neighbor-joining method is the most commonly used, and the bootstrap value is often set to 1000 replicates.

[0046] A 1404-bp 16S rRNA gene sequence was obtained through PCR and gene sequencing. Comparison of the 16S rRNA genes revealed a 99.57% similarity between the strain and Achromobacter anxifer strain LMG 26857. These results indicate that the bacterium DY-11 isolated in the present invention belongs to the species Achromobacter anxifer, which is registered in GenBank as NR 117708.1.

[0047] The 16S rRNA gene sequence of strain DY-11 is as follows:

[0048] TTACCTGCAAGTCGAACGGCAGCACGGACTTCGGTCTGGTGGCGAGTGGCGAACGGG

[0049] TGAGTAATGTATCGGAACGTGCCCAGTAGCGGGGGATAACTACGCGAAAGCGTAGCTA

[0050] ATACCGCATACGCCCTACGGGGGAAAGCAGGGGATCGCAAGACCTTGCACTATTGGAG

[0051] CGGCCGATATCGGATTAGCTAGTTGGTGGGGTAACGGCTCACCAAGGCGACGATCCGT

[0052] AGCTGGTTTGAGAGGACGACCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTA

[0053] CGGGAGGCAGCAGTGGGGAATTTTGGACAATGGGGGAAACCCTGATCCAGCCATCCC

[0054] GCGTGTGCGATGAAGGCCTTCGGGTTGTAAAGCACTTTTGGCAGGAAAGAAACGTCG

[0055] CGGGTTAATACCCCGCGAAACTGACGGTACCTGCAGAATAAGCACCGGCTAACTACGT

[0056] GCCAGCAGCCGCGGTAATACGTAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAA

[0057] GCGTGCGCAGGCGGTTCGGAAAGAAAGATGTGAAATCCCAGAGCTTAACTTTGGAAC

[0058] TGCATTTTTAACTACCGAGCTAGAGTGTGTCAGAGGGAGGTGGAATTCCGCGTGTAGC

[0059] AGTGAAATGCGTAGATATGCGGAGGAACACCGATGGCGAAGGCAGCCTCCTGGGATA

[0060] ACACTGACGCTCATGCACGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAG

[0061] TCCACGCCCTAAACGATGTCAACTAGCTGTTGGGGCCTTCGGGCCTTGGTAGCGCAGC

[0062] TAACGCGTGAAGTTGACCGCCTGGGGAGTACGGTCGCAAGATTAAAACTCAAAGGAA

[0063] TTGACGGGGACCCGCACAAGCGGTGGATGATGTGGATTAATTCGATGCAACGCGAAA

[0064] AACCTTACCTACCCTTGACATGTCTGGAATCCTGAAGAGATTTAGGAGTGCTCGCAAG

[0065] AGAACCGGAACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGG

[0066] TTAAGTCCCGCAACGAGCGCAACCCTTGTCATTAGTTGCTACGAAAGGGCACTCTAAT

[0067] GAGACTGCCGGTGACAAACCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCC

[0068] TTATGGGTAGGGCTTCACACGTCATACAATGGTCGGGACAGAGGGTCGCCAACCCGCG

[0069] AGGGGGAGCCAATCCCAGAAACCCGATCGTAGTCCGGATCGCAGTCTGCAACTCGAC

[0070] TGCGTGAAGTCGGAATCGCTAGTAATCGCGGATCAGCATGTCGCGGTGAATACGTTCC

[0071] CGGGTCTTGTACACACCGCCCGTCACACCATGGGAGTGGGTTTTACCAGAAGTAGTTA

[0072] GCCTAACCGCAAGGGGGGCGATAC

[0073] The phylogenetic tree was constructed using the 16S rRNA gene sequence of DY-11 and the 16S rRNA gene sequence with the highest similarity to it, thereby obtaining the homology results between the 16S rRNA gene of DY-11 and the 16S rRNA gene with the highest similarity to it. The phylogenetic tree constructed using the neighbor-joining method is shown in Figure 2 Currently, there are few reports on the application of this strain in the environmental field. Therefore, obtaining highly efficient phenanthrene and benzopyrene-degrading bacteria has important theoretical and practical significance for the treatment and deep remediation of phenanthrene- and benzopyrene-contaminated soils and PAHs pollution.

[0074] The above results show that the strain DY-11 isolated in the present invention is the species Achromobacter anxifer, and is named Achromobacter anxifer DY-11, which was deposited in the Guangdong Provincial Microbiological Culture Collection Center (GDMCC) on March 12, 2025, address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou City, Guangdong Province, Postal Code: 510070, and the deposit number is: GDMCC No: 66005.

[0075] Example 2: Growth conditions of Achromobacter anxifer DY-11

[0076] 1. Determination of growth temperature: Prepare the liquid nutrient culture medium required for the growth of the strain, and sterilize it in an autoclave after preparation. Inoculate the activated strain into the culture medium (experimental group), and use a culture medium without bacteria as a control (control group). Incubate the culture medium at different temperatures for 12 hours. The control group and the experimental group corresponding to each temperature have three replicates. Observe the growth of bacteria every day. When the results are difficult to distinguish with the naked eye, use a visible-ultraviolet spectrophotometer to measure the absorbance of the culture medium at a wavelength of λ=600nm. Finally, the growth temperature and the optimal growth temperature range of the new bacteria are obtained. The test temperatures are as follows: 18℃, 23℃, 28℃, 33℃, and 38℃.

[0077] 2. Determination of Growth pH: Prepare the liquid nutrient medium required for strain growth and adjust the pH of the culture medium using the following buffer system: pH 4.0-5.0, 0.1 mol / L sodium citrate and 0.1 mol / L citric acid; pH 6.0-8.0, 0.1 mol / L NaOH and 0.1 mol / L KH2PO4; pH 9.0-10.0, 0.1 mol / L NaHCO3 and 0.1 mol / L Na2CO3; pH 11.0, 0.1 mol / L NaOH and 0.05 mol / L Na2HPO4. Inoculate the bacteria into the culture medium in triplicate for each pH value. Use an uninoculated culture medium as a control. Incubate the culture medium at the optimal temperature for the growth of the new bacteria for 12 hours. Observe bacterial growth. If the results are difficult to distinguish visually, measure the absorbance of the culture medium at a wavelength of λ = 600 nm using a visible-UV spectrophotometer. Finally, determine the pH at which the new bacteria can grow and the optimal pH range for growth. The pH tested was as follows: 4.0, 5.0, 6.0, 7.0, 8.0, 9.0.

[0078] 3. Salt Concentration Tolerance: Prepare the liquid nutrient medium required for strain growth and adjust the salt concentration of the medium. Inoculate the activated new bacteria into the sterilized culture medium. Perform three replicates for each salt concentration. Use an uninoculated culture medium as a control. Incubate the culture medium at the optimal salinity for the growth of the new bacteria for 12 hours. Observe the bacterial growth. If the bacteria are difficult to distinguish with the naked eye, use a visible-ultraviolet spectrophotometer to measure the absorbance of the culture medium at a wavelength of λ = 600nm. This is best to determine the salt concentration range that the new bacteria can tolerate. Test salt concentrations as follows: 0%, 2%, 4%, 6%, 8%, and 10%.

[0079] like Figure 3 As shown, in nutrient broth medium, DY-11 can grow at a temperature of 18-38°C, with the optimal growth temperature being 28°C, the enrichment temperature of the bacterium; the bacterium can grow at a pH of 4.0-9.0, with the optimal growth pH being 7.0; the bacterium has a weak salt tolerance and can grow at a salt concentration of 0% to 4%, and grows best without the addition of sodium chloride.

[0080] Example 3: Phenanthrene and benzopyrene degradation experiment

[0081] Based on the above experimental results, the optimal growth conditions for the strain were determined to be 28°C, pH 7.0, and no NaCl. Growth and degradation experiments of strain DY-11 in high concentrations of phenanthrene and benzopyrene were conducted under these conditions.

[0082] The strain DY-11 in the logarithmic growth phase was inoculated at a mass fraction of 10% (the absorbance OD of the original bacterial solution was 0.20, and the number of cells in the original bacterial solution was 1.1×10 7 CFU·mL -1 ) were inoculated with an initial phenanthrene concentration of 50 mg·L -1 Or the initial benzopyrene concentration is 25 mg·L -1 The culture was carried out in an inorganic salt medium (formula see Table 1, pH 7.0) at 28°C with shaking for 7 days. The experiment was repeated three times. The treatment without the addition of strain DY-11 was used as the control treatment.

[0083] Take each treatment sample for chemical analysis, the specific steps are as follows:

[0084] (1) Sample pretreatment: Each culture sample was extracted with dichloromethane, and 5 μL of a recovery indicator at a concentration of 200 mg / L was added (for samples treated with phenanthrene and benzopyrene, deuterated polycyclic aromatic hydrocarbons were added). After thorough shaking, the sample was transferred to a separatory funnel and allowed to stand. After separation, the organic phase was collected, and the lower layer of liquid was returned to the shake flask and extracted again with an equal volume of dichloromethane. The combined extracts were transferred to a flat-bottomed flask containing an appropriate amount of activated copper sheets and rotary evaporated to concentrate to about 2 mL. A small amount of n-hexane (about 5 mL) was added and rotary evaporated to 2 mL. The washing was repeated three times, and the organic solvent was replaced with n-hexane. The concentrated solution after replacement was purified using a glass column (about 9 mm in diameter). The column fillings were 3 cm 3% deactivated neutral alumina, 3 cm 3% deactivated silica gel, and 1 cm anhydrous sodium sulfate from bottom to top. Activate the column with an appropriate amount of n-hexane. Elute the packed column with 15 mL of a 1:1 hexane / dichloromethane mixture. Collect approximately 15 mL of the eluate in a brown reagent bottle and concentrate it to approximately 0.5 mL using nitrogen purging. Transfer the eluate to a 1.5 mL cell flask and store frozen. Add 5 μL of the internal standard hexamethylbenzene (200 mg / L) before measurement.

[0085] (2) Instrumental analysis: The PAHs content in each treated sample was determined using an Agilent 7890 gas chromatograph-5975 mass spectrometer. The chromatographic column used was an Agilent DB 5-MS capillary column (column length 30m, inner diameter 0.25mm, film thickness 0.25μm). The PAHs content was determined using an Agilent 7890 gas chromatograph-5975 mass spectrometer. The separation and analysis were performed using an Agilent DB 5-MS capillary column (column length 30m, inner diameter 0.25mm, film thickness 0.25μm). The data obtained were processed using an Agilent chromatography workstation, and the quantification of phenanthrene and benzopyrene was performed using a 6-point calibration curve and an internal standard method. The microbial cell concentration was determined using photoelectric turbidimetry, expressed as OD, which is the optical density value of the bacterial solution sample when ultraviolet light passes through it at a wavelength of 600nm.

[0086] According to GC-MS determination and analysis, strain DY-11 was able to degrade phenanthrene and benzopyrene ( Figure 4 ), and in the presence of 50 mg·L -1 Concentration of phenanthrene and 25 mg·L -1 After culturing for 7 days in an inorganic salt culture medium containing a high concentration of benzo[a]pyrene, the degradation rates reached over 65%, 82.1% for phenanthrene and 67.8% for benzo[a]pyrene, respectively. This indicates that strain DY-11 is capable of degrading both phenanthrene and benzo[a]pyrene, and has a strong tolerance to these two compounds.

[0087] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Achromobacter anxifer DY-11, preservation number: GDMCC No: 66005.

2. Use of Achromobacter anxifer DY-11 according to claim 1 in degrading polycyclic aromatic hydrocarbons.

3. The application according to claim 2, wherein The polycyclic aromatic hydrocarbons include phenanthrene and benzo[a]pyrene.

4. The application according to claim 2, characterized in that, It is to apply the bacterial suspension of Achromobacter anxifer DY-11 to the water body or soil polluted by polycyclic aromatic hydrocarbons.

5. Use of Achromobacter anxifer DY-11 according to claim 1 in preparing a polycyclic aromatic hydrocarbon degrading bacterial agent.

6. A polycyclic aromatic hydrocarbon degrading microbial agent, characterized in that, It contains Achromobacter anxifer DY-11 according to claim 1 or its pure culture as an active ingredient.

7. Use of Achromobacter anxifer DY-11 according to claim 1 or the bacterial agent according to claim 6 in the bioremediation of polycyclic aromatic hydrocarbon-polluted environments.

8. The application according to claim 7, characterized in that The polycyclic aromatic hydrocarbon-polluted environment includes polycyclic aromatic hydrocarbon-polluted water bodies and / or soils.

9. The application according to claim 7, characterized in that, The polycyclic aromatic hydrocarbons include phenanthrene and benzo[a]pyrene.

10. A method for degrading polycyclic aromatic hydrocarbons, characterized in that, Applying Achromobacter anxifer DY-11 according to claim 1 or the bacterial agent according to claim 6 to the polycyclic aromatic hydrocarbon-polluted environment to degrade polycyclic aromatic hydrocarbons.

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