A diazonium plant bacterium capable of degrading benzene compounds and its application

Abstract

This invention provides a diazotrophic bacterium capable of degrading benzene compounds and its applications. Specifically, this invention provides a diazotrophic bacterium strain, which has the preservation number CGMCC No. 32883. The diazotrophic bacterium strain of this invention is named DPB548, and it can be used for the degradation of benzene compounds in water or air.

Description

Technical Field

[0001] This invention relates to a plant bacillus and its application, specifically a strain of Phytobacter diazotrophicus capable of degrading benzene compounds and its application in the degradation of benzene compounds. Background Technology

[0002] Indoor benzene compounds mainly include volatile organic compounds such as benzene, toluene, ethylbenzene, and xylene. They are widely found in decoration materials such as paints, coatings, adhesives, cleaning agents, and carpets. Their release period can last for several years, posing a great threat to residents' health.

[0003] Benzene contamination poses various health hazards to humans. Short-term inhalation of high concentrations of benzene can cause acute poisoning, manifesting as dizziness, headache, nausea, vomiting, and fatigue; in severe cases, it can lead to loss of consciousness. Due to its dangerous nature, benzene is classified as a Group 1 carcinogen by the World Health Organization. Long-term exposure to low concentrations of benzene can damage the hematopoietic system, potentially causing leukopenia, aplastic anemia, and even increasing the risk of leukemia. Long-term inhalation of toluene and xylene can damage the nervous system, leading to symptoms such as memory loss, poor concentration, and mood swings, and may also affect liver and kidney function. Benzene contamination poses a greater threat to the health of children and pregnant women, potentially causing fetal developmental abnormalities, miscarriage, or neonatal health problems.

[0004] Currently, there are various methods for controlling indoor benzene pollution, mainly including ventilation, activated carbon adsorption, air purifiers, plant adsorption, and physical and chemical treatments. Each method has its advantages and disadvantages, and a combination of methods is usually necessary to achieve the best results.

[0005] Ventilation is the simplest and lowest-cost method. Increasing air circulation dilutes and removes free benzene compounds from the room. However, this method has limited effectiveness, only temporarily reducing indoor benzene concentrations and is limited by weather conditions. Activated carbon has good adsorption properties for harmful VOCs, but its adsorption capacity is limited and usually only lasts for a period of time, requiring frequent replacement or regeneration. Furthermore, activated carbon adsorbs benzene compounds passively and cannot treat sources of long-term, slow-release benzene compounds, especially high concentrations, and is more suitable for small spaces. Photocatalytic benzene removal uses photocatalysts to decompose benzene compounds under ultraviolet or visible light. However, this method relies on the light source, has a limited catalyst lifespan, and is only suitable for low concentrations. Chemical methods typically involve spraying chemical reagents (catalysts or oxidants) to decompose benzene compounds. Improper use of chemical reagents can cause secondary pollution, and this method is unsuitable for long-term, continuous pollution sources. Using air purifiers is a common method of air purification. Modern air purifiers are equipped with various filters and purification technologies, such as HEPA filters and activated carbon filters, which can effectively remove benzene compounds from the air. However, air purifiers have drawbacks such as high cost, limited effectiveness, and limited purification range. Plasma purification technology uses a high-voltage electric field to generate plasma, which decomposes benzene compounds. This method produces harmful substances such as ozone, and its cost, maintenance, and operating costs are relatively high, making it unsuitable for long-term benzene removal.

[0006] New and efficient air purification solutions need to be developed. Summary of the Invention

[0007] The inventors of this invention discovered a strain of *Phytobacter diazotrophicus* capable of degrading benzene compounds, which can be used to prepare microbial preparations for the degradation of benzene compounds in water or air. This strain is named DPB548 and is deposited at the China General Microbiological Culture Collection Center (CGMCC) (Address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, 100101, China), dated December 2, 2024; accession number: CGMCC No. 32883; classification and nomenclature: *Phytobacter diazotrophicus*.

[0008] The 16S rRNA sequence of Phytobacter diazotrophicus DPB548 (SEQ ID NO.1):

[0009] TTGAAGAGTTTGATCATGGCTCAGATTGAACGCTGGCGGCAGGCCTAACACATGCAAGTCGAACGGTAGCACAGAGAGCTTGCTCTCGGGTGACGAGTGGCGGACGGGTGAGTAATGTCTGGGAAACTGCCCGATGGAGGGGGATAACTACTGGAAACGGTAGCTAATACCGCATAATGTCGCAAGACCAAAGAGGGGGACCTTCGGGCCTCTTGCCATCGGATGTGCCCAGATGGGATTAGCTAGTTGGTGAGGTAATGGCTCACCAAGGCGACGATCCCTAGCTGGTCTGAGAGGATGACCAGCCACACTGGAACTGAGACACGGTCCAGACTCCTACGGGAGGCAGCAGTGGGGAATATTGCACAATGGGCGCAAGCCTGATGCAGCCATGCCGCGTGTGTGAAGAAGGCCTTCGGGTTGTAAAGCACTTTCAGCGGGGAGGAAGGCGATACGGTTAATAACCGTGTTGATTGACGTTACCCGCAGAAGAAGCACCGGCTAACTCCGTGCCAGCAGCCGCGGTAATACGGAGGGTGCAAGCGTTAATCGGAATTACTGGGCGTAAAGCGCACGCAGGCGGTCTGTCAAGTCGGATGTGAAATCCCCGGGCTCAACCTGGGAACTGCATTCGAAACTGGCAGGCTTGAGTCTTGTAGAGGGGGGTAGAATTCCAGGTGTAGCGGTGAAATGCGTAGAGATCTGGAGGAATACCGGTGGCGAAGGCGGCCCCCTGGACAAAGACTGACGCTCAGGTGCGAAAGCGTGGGGAGCAAACAGGATTAGATACCCTGGTAGTCCACCGCCGTAAACGATGTCGACTTGGAGGTTGTGCCCTTGAGGCGTGGCTTCCGGAGCTAACGCGTTAAGTCGACCGCCTGGGGAGTACGGCCGCAAGGTTAAAACTCAAATGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGATGCAACGCGAAGAAC CTTACCTGGTCTTGACATCCACGGAATTTGGCAGAGATGCCTTAGTGCCTTCGGGAACCGTGAGACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTTGTGAAATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTTATCCTTTGTTGCCAGCGGTCCGGCCGGGAACTCAAAGGAGACTGCCAGTG ATAAACTGGAGGAAGGTGGGGATGACGTCAAGTCATCATGGCCCTTACGACCAGGGCTACACACGTGCTACAATGGCATATACAAAGAGAAGCGACCTCGCGAGCAAGCGGACCTCATAAAGTATGTCGTAGTCCGGATTGGAGTCTGCAACTCGACTCCATGAAGTCGGAATCGCTAGTAATCG TGGATCAGAATGCCACGGTGAATACGTTCCCGGGCCTTGTACACACCGCCCGTCACACCATGGGAGTGGGTTGCAAAAGAAGTAGGTAGCTTAACCTTCGGGAGGGCGCTTACCACTTTGTGATTCATGACTGGGGTGAAGTCGTAACAAGGTAACCGTAGGGGAACCTGCGGTTGGATCACCTCCTT

[0010] Thus, on the one hand, the present invention provides a diazotrophic plant bacterium (Phytobacter diazotrophicus) with accession number CGMCC No. 32883.

[0011] On the other hand, the present invention also provides a bacterial preparation containing the diazobacterium plantarum DPB548 described in the present invention (i.e., the strain with preservation number CGMCC No. 32883, or diazobacterium plantarum DPB548).

[0012] According to a specific embodiment of the present invention, the bacterial preparation of the present invention can be a liquid preparation or a solid preparation of live bacteria.

[0013] In some specific embodiments of the present invention, the bacterial preparation is a liquid preparation.

[0014] In some other specific embodiments of the present invention, the bacterial preparation is a solid preparation, such as lyophilized powder.

[0015] According to a specific embodiment of the present invention, the bacterial preparation of the present invention may include one or more of the following formulations:

[0016] Flower nutrient soil containing the diazoxide-eating plant bacteria described in this invention;

[0017] A bacterial solution containing the diazoxide-eating plant bacillus described in this invention is used to irrigate indoor green plants; preferably, the green plants are pothos or other common indoor green plants, planted in well-ventilated flower pots;

[0018] A carrier packing material for a purification device containing the diazoxide-eating plant bacillus described in this invention; preferably, the carrier packing material is one or more of nano-carrier packing material and agar gel;

[0019] A liquid preparation containing the diazoxide-eating plant bacillus described in this invention; preferably, the liquid preparation is a spray.

[0020] On the other hand, the present invention also provides a method for culturing the aforementioned diazoxide-eating plant bacillus, the method comprising:

[0021] The diazoxide-eating plant bacillus described in this invention is inoculated into a culture medium for fermentation culture.

[0022] According to a specific embodiment of the present invention, in the cultivation method of the present invention, the culture medium is a culture medium containing yeast powder and / or yeast peptone.

[0023] According to a specific embodiment of the present invention, in the cultivation method of the present invention, the fermentation cultivation conditions are 25-37℃ and the fermentation time is 14-24 hours.

[0024] According to a specific embodiment of the present invention, the fermentation culture broth of the present invention can be prepared into a liquid bacterial agent as needed, or it can be further prepared into a powder by freeze-drying.

[0025] In some specific embodiments of the present invention, the present invention also provides a method for preparing a freeze-dried powder containing the aforementioned diazoxide-eating plant bacteria, the method comprising:

[0026] The aforementioned diazoxide-eating plant bacteria are fermented and then freeze-dried with the addition of a protective agent to prepare freeze-dried powder.

[0027] On the other hand, the present invention also provides the use of the *Bacillus diazoxide* or the bacterial preparation described herein in the preparation of formulations for degrading benzene series compounds.

[0028] According to a specific embodiment of the present invention, the benzene series compounds include one or more of benzene, toluene, ethylbenzene, and xylene.

[0029] On the other hand, the present invention also provides a method for degrading benzene compounds, the method comprising:

[0030] Contact the diazoxide-eating plant bacillus and the bacterial preparation described in this invention with the sample or environment of the benzene series compounds to be degraded.

[0031] According to some specific embodiments of the present invention, the sample of the benzene series compounds to be degraded is a water body, and the method includes adding the diazobacterium plantarum or the bacterial preparation to the water body.

[0032] According to some specific embodiments of the present invention, the environment in which the benzene series compounds to be degraded are indoor air environments, and the method includes preparing a bacterial preparation containing *Bacillus diazoxide* into a bacterial solution or thoroughly mixing it with soil, and filling the sealed bag with a bacterial preparation filler. Preferably, the sealed bag material is a non-woven fabric or other small-pore material that allows air circulation. The concentration of the bacterial preparation can be 1–5 × 10⁻⁶. 7 CFU / g.

[0033] According to some specific embodiments of the present invention, the *Bacillus diazoxide* of the present invention can be used in conjunction with green plants to prepare a bacterial solution for watering the roots of plants planted in well-ventilated flowerpots. The device is placed in an environment where benzene compounds are to be degraded, thereby degrading indoor benzene compounds and beautifying the indoor environment. Preferably, the plants are common indoor green plants such as pothos. The amount of bacterial solution added can be 10-50 mL / time. The concentration of the bacterial preparation can be 1×10⁻⁶. 8 ~10 9 CFU / mL.

[0034] According to some specific embodiments of the present invention, the bacterial solution prepared by *Bacillus diazoxide* is filled into a nano-carrier packing material by using it in conjunction with a small aerodynamic device, or prepared into a gel with agar or the like and filled into an alumina foam carrier packing material. The bacterial preparation is placed in the small aerodynamic device, and a fan is used to purify indoor air containing benzene compounds by sending it into the packing material. The concentration of the bacterial preparation can be 1×10⁻⁶. 8 ~10 9 CFU / mL.

[0035] According to some specific embodiments of the present invention, a spray solution is prepared by adding a thickener and a stabilizer for spraying onto indoor object surfaces. Preferably, the thickener is sodium alginate, added at an amount of 0.05% to 0.2%, and the stabilizer can be phosphate buffer solution with a pH of 7.4. The concentration of the bacterial preparation in the spray solution form can be 1 to 2 × 10⁻⁶. 8 CFU / mL.

[0036] The *Phytobacter diazotrophicus* of this invention is used to degrade benzene compounds, offering advantages such as being environmentally friendly, highly persistent, efficient, free of secondary pollution, and cost-effective. Furthermore, it can adapt to various environmental conditions and is suitable for wide application. Compared to traditional benzene removal methods, the microbial benzene removal method of this invention features high specificity, no harmful byproducts, and high cost-effectiveness. Attached Figure Description

[0037] Figure 1 A phylogenetic tree was constructed based on the 16S rRNA sequences of the strain DPB548 of this invention and other plant bacilli.

[0038] Figure 2 The GC elution chromatograms are for several benzene compounds involved in this invention.

[0039] Figure 3 Peak diagrams of benzene series compounds prepared for two time points.

[0040] Figure 4 This shows the increase in biomass (expressed as OD) of strain DPB548 after 24 hours of culture in media using various benzene series compounds as the sole carbon source. 600 express).

[0041] Figure 5 The left image shows the residual amounts of each benzene series compound in the liquid after 24 hours of treatment by strain DPB548 (expressed as peak area) and the corresponding degradation rates of each benzene series compound (right image).

[0042] Figure 6 The results showed that strain DPB548 had an initial total concentration of 120 g / m³ in the air. 3 The residual amount of each benzene series compound in the upper air of the glass test tube after 24 hours of treatment with the mixed benzene series compounds (left, expressed as peak area) and the corresponding degradation rate of each benzene series compound (right).

[0043] Figure 7 The results showed that strain DPB548 had an initial total concentration of 60 g / m³ in the air. 3 The residual amount of each benzene series compound in the upper air of the glass test tube after 24 hours of treatment with the mixed benzene series compounds (left, expressed as peak area) and the corresponding degradation rate of each benzene series compound (right).

[0044] Preservation of biological materials for patent procedures:

[0045] Phytobacter diazotrophicus strain DPB548:

[0046] Deposit date: December 2, 2024;

[0047] Preservation institution: China General Microbiological Culture Collection Center (CGMCC);

[0048] Address of the depository: Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, 100101, China;

[0049] Accession number: CGMCC No. 32883;

[0050] Classification and nomenclature: Phytobacter diazotrophicus. Detailed Implementation

[0051] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention.

[0052] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art.

[0053] In addition to the specific methods, equipment, and reagents used in the embodiments, based on the knowledge of those skilled in the art and the description of this invention, any prior art methods, equipment, and materials similar to or equivalent to those described, equipment, and reagents in the embodiments of this invention can be used to implement this invention.

[0054] Unless otherwise stated, the experimental methods, detection methods and preparation methods disclosed in this invention all adopt conventional techniques in this technical field.

[0055] To facilitate understanding of this invention, certain technical and scientific terms are specifically defined below. Unless otherwise expressly defined herein, all other technical and scientific terms used herein have the meanings commonly understood by those skilled in the art.

[0056] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment / implementation, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0057] Example 1: Screening and identification of Phytobacter diazotrophicus strain DPB548

[0058] 1. Isolation and culture of bacteria targeting benzene compounds

[0059] Place 45g of commercially available horticultural potting soil in a well-sealed container, and add 25mL of a 400mg / L benzene series compound solution (benzene, toluene, ethylbenzene, xylene, and various benzene series compounds prepared in a 1:1:1:1 ratio). Place the container in a fume hood, and water the soil a second time after half a month. After one month of treatment, collect the treated soil for microbial isolation.

[0060] Specifically, 5g of soil was placed in a 50mL centrifuge tube containing 20mL of LB medium and incubated in a constant-temperature shaker for 72h (200rpm, 25℃). The cultured sample was then centrifuged at 14000×g for 2min, and the bacterial cells were collected and frozen for subsequent 16S sequencing. 250μL of the enriched culture was added to 4mL of M9 medium (containing the basic components: Na2HPO4 (12.8g / L), KH2PO4 (3.0g / L), NaCl (0.5g / L), NH4Cl (1.0g / L)) containing 50mg / L benzene series compounds. After preparation and sterilization, 2μM MgSO4 and 100nM MgSO4 were added. The bacterial culture was prepared for 2 days (200 rpm, 25℃) in CaCl2, with trace elements ZnSO4·7H2O (0.15 g / L), MnSO4·H2O (0.26 g / L), CoCl2·6H2O (0.03 g / L), FeSO4·7H2O (4.50 g / L), NiCl2·6H2O (0.02 g / L), CuCl2 (0.01 g / L), Na2MoO4·2H2O (0.10 g / L), and H3BO3 (0.06 g / L). After 2 days, the bacterial culture was preserved and the bacterial cells were collected. The culture was then inoculated again at a 5% inoculum into M9 medium containing 100 mg / L benzene series solution and cultured for 3 days. After 3 days, the bacterial culture was preserved and the bacterial cells were collected. Similarly, 5% inoculum was inoculated into M9 medium containing 200 mg / L benzene series solution and cultured, and passaged three times at a concentration of 200 mg / L, with each passage cultured for 2 days. Single bacteria were isolated by dilution and plating of the third-generation bacterial culture.

[0061] The above bacterial cultures were serially diluted using... 1 / 5TSB culture medium plate, select 10 -3 10 -4 10 -5 10 -6 Four concentrations of dilution were plated. After single bacteria grew, they were picked and cultured in their corresponding liquid culture media. After 3 days, they were streaked for purification, and then single bacteria were picked and cultured in liquid media again. After two purifications, the bacteria were preserved.

[0062] 2. Bacterial species identification targeting benzene compounds

[0063] For the screened strains, species identification was performed based on their 16S rRNA sequences. 5 μL of bacterial culture was transferred to a PCR tube, 45 μL of bacterial lysis buffer was added, and the mixture was incubated at 90°C for 10 min. Further, the full-length 16S rRNA of the strain was obtained via PCR.

[0064] Preparation of the reaction mixture: 1 μL DNA template, 1 μL 27F forward primer (10 μM), 1 μL 1492R reverse primer (10 μM), 1 μL PrimeSTAR Max DNA Polymerase (2×), and 7 μL ddH2O. PCR reaction program: ① 98℃ for 3 min, ② 98℃ for 15 sec, ③ 56℃ for 15 sec, ④ 72℃ for 15 sec, cycle ② to ④ for 35 times, ⑤ 72℃ for 5 min.

[0065] The 27F forward primer sequence is 5′-AGAGTTTGATCCTGGCTCAG-3′ (SEQ ID NO.2).

[0066] The reverse primer sequence for 1492R is 5′-TATACGGYTACCTTGTTACGACTT-3′ (SEQ ID NO.3).

[0067] The PCR products were subjected to Sanger sequencing, and the sequences were aligned using BLAST on the NCBI website. Based on the similarity between the target sequence and nucleic acid sequences in the database, the isolated strain capable of degrading benzene compounds was identified as *Phytobacter diazotrophicus*. A phylogenetic tree constructed based on the 16S rRNA sequences of strain DPB548 and other plant bacilli is shown below. Figure 1 Furthermore, the present invention performed whole-genome sequencing on this strain. According to GTDB (Genome Taxonomy Database) annotations, the average nucleotide identity (ANI) between the strain of the present invention and the published whole-genome sequence of Phytobacter diazotrophicus DSM17806 is 95%. Based on the principle that an ANI value ≥95%-96% is generally considered to indicate that two genomes belong to the same species, the accurate species information of the strain of the present invention was finally confirmed as Phytobacter diazotrophicus, with the Chinese name *Phytobacter diazotrophicus*.

[0068] The strain of this invention was ultimately named DPB548. This strain has been deposited at the China General Microbiological Culture Collection Center (CGMCC) (Address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences, 100101, China), deposited on December 2, 2024; accession number: CGMCC No. 32883; classification: Phytobacter diazotrophicus.

[0069] Example 2: Detection of the degradation ability of Phytobacter diazotrophicus strain DPB548 on benzene series compounds in liquid.

[0070] This experiment used an Agilent 8890 gas chromatograph system to detect the concentration of benzene compounds in the upper air of glass shaker tubes.

[0071] The total volume of the glass culture tubes used in the experiment was 30 mL. The glass tubes and rubber stoppers were sterilized and dried before use. 5 mL of M9 culture medium was added, followed by a stock solution of benzene, toluene, ethylbenzene, and xylene (equal parts of m-xylene, p-xylene, and o-xylene), with a concentration of 100 mg / mL, resulting in a working concentration of 200 mg / L for the benzene series compounds. The glass tubes were quickly sealed with rubber stoppers and secured with aluminum rings. The glass tubes were then shaken for 30 seconds to mix thoroughly. Based on the poor water solubility of benzene series compounds, the benzene series compound content in the upper air layer of the glass culture tubes was directly measured.

[0072] Manual GC injection using headspace sampling was employed. Specifically, 1 mL of upper-layer air was drawn through a 1 mL syringe with a sealed stopper and manually injected into the GC injection port. Experimental conditions were set as follows: the column used was a DB-WAX (20℃-230℃, 30m*500μm*1μm), with a flow rate of 8 mL / min, a pressure of 5.027 psi, and a constant flow rate. Before the injection port SSL: the heater was set to 200℃, the pressure to 3.3074 psi, the total flow rate to 58 mL / min, and the septum purge flow rate to 3 mL / min. The temperature program was set as follows: initial column temperature 40℃, equilibration time 0.5 min, hold time 3 min, run time 3 min, heating rate 20℃ / min to 190℃, hold time 5 min, run time 15.5 min, followed by a run at 230℃ for 3 min. The carrier gas used in this experiment was nitrogen, with a split ratio of 10:1. The detector was FID, the heater temperature was set to 250℃, the air flow rate was set to 400mL / min, the hydrogen fuel flow rate was 30mL / min, the tail gas flow rate (N2) was 25mL / min, the carrier gas flow rate calibration was constant tail gas + fuel flow rate, the flame was selected, the signal acquisition frequency was 50Hz, and the minimum peak width was 0.004min.

[0073] The elution times of the six benzene series compounds are shown in the figure. Figure 2 See Table 1 for details.

[0074] Table 1. Peak details of benzene series compounds in mixed standards (each benzene series compound has a concentration of 200 mg / L).

[0075]

[0076] To test the stability of the system, two M9 culture medium samples containing benzene compounds were prepared. One sample was prepared and placed in a constant temperature shaker at 25℃ and 200 rpm for 24 hours. The other sample was prepared fresh using the same method before instrumentation. The concentration of benzene compounds in the upper air of both samples was measured. The peak areas of benzene compounds in the upper air of the samples prepared at the two time points were consistent. Figure 3 This indicates that the experimental method is feasible.

[0077] Furthermore, the strain's degradation ability for various benzene compounds was tested. Specifically, the strain was placed in... 1 Pre-culture overnight in 2 TSB liquid medium at 200 rpm and 25°C. Centrifuge the bacterial suspension at 6000 rpm for 6 min, discard the original medium, resuspend in M9 culture solution, and inoculate into glass shaker tubes containing M9 medium. Adjust OD. 600 =0.5, total volume adjusted to 5mL. Add 10μL of a stock solution with a concentration of 100mg / mL for benzene, toluene, ethylbenzene, and xylene (equal parts m-xylene, p-xylene, and o-xylene), respectively, to achieve a working concentration of 200mg / L for each benzene series compound. The control group was a blank sample without added bacteria. Each treatment was replicated in triplicate. The glass shaker tubes were secured with aluminum rings to ensure airtightness. All treatment groups and the control group were placed in a 25℃ constant temperature shaker at 200rpm for 24h. The amount of benzene series compounds in the upper air of the glass tubes was measured, and the degradation rate of each benzene series compound by the strain and the growth status of the strain (OD) were calculated. 600 ).

[0078] The peak area of ​​each benzene series compound represents the content of the substance. The degradation rate of each benzene series compound by the strain after 24 hours was calculated by comparing it with the control group. The calculation formula is as follows: Where A is the peak area of ​​the control group and B is the peak area of ​​the strain treatment group.

[0079] The strain DPB548 of this invention, when cultured for 24 hours in M9 medium with benzene as the sole carbon source, exhibits an increase in growth rate as follows: Figure 4 As shown (OD of 24h) 600 Subtract 0h OD 600 The degradation rate of benzene was 19.52% after 24 hours; the degradation rate of toluene was 21.16%; the degradation rate of ethylbenzene was 21.58%; and the degradation rate of xylene was 58.52%. Figure 5 ).

[0080] Furthermore, 5 mL of solid agar medium was prepared using glass shaker tubes, and 100 μL of bacterial suspension was spread evenly on the slant (OD). 600=0.5), mix the six benzene compounds in equal proportions, and add 5 μL dropwise to the tube wall near the bacteria, ensuring that the final concentration of each benzene compound is 100 mg / L, and that the concentration of each benzene compound in the air after complete volatilization is 20 g / m³. 3 The overall concentration of benzene series compounds was 120 g / m³. 3 .like Figure 6 As shown, after 24 hours of treatment, the concentrations of benzene compounds in the air all decreased. The degradation rate of benzene by strain DPB548 of the present invention was 20.25%; the degradation rate of toluene was 18.13%; the degradation rate of ethylbenzene was 28.17%; and the degradation rate of all xylenes was 26.54%.

[0081] Six benzene compounds were mixed in equal proportions, and 5 μL was added dropwise to the tube wall near the bacteria to ensure that the final concentration of each benzene compound was 50 mg / L, and that the concentration of each benzene compound in the air after complete volatilization was 10 g / m³. 3 The overall concentration of benzene series compounds was 60 g / m³. 3 .like Figure 7 As shown, after 24 hours of treatment, the concentrations of benzene compounds in the air all decreased. The degradation rate of benzene by strain DPB548 of the present invention was 21.25%; the degradation rate of toluene was 22.57%; the degradation rate of ethylbenzene was 34.68%; and the degradation rate of all xylenes was 31.34%.

[0082] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions also fall within the protection scope of this invention.

Claims

1. A type of diazoxide-eating plant bacillus ( Phytobacter diazotrophicus It has the accession number CGMCC No.32883.

2. A bacterial preparation containing the diazoxide-eating plant bacillus as described in claim 1.

3. The bacterial preparation according to claim 2, wherein it is a liquid or solid preparation of live bacteria.

4. The microbial preparation according to claim 2, comprising one or more of the following formulations: Flower nutrient soil containing the diazoxide-eating plant bacteria as described in claim 1; A bacterial solution containing the diazoxide-eating plant bacteria as described in claim 1 for irrigating indoor green plants; A carrier packing material for a purification device containing the diazoxide-eating plant bacteria as described in claim 1; A liquid preparation containing the diazoxide-eating plant bacillus as described in claim 1.

5. The bacterial preparation according to claim 4, wherein, The carrier filler is one or more of nano-carrier fillers and agar gel.

6. The bacterial preparation according to claim 4, wherein, The liquid formulation is a spray.

7. A method for culturing the diazoxide-eating plant bacillus according to claim 1, the method comprising: The diazoxide-eating plant bacillus described in claim 1 is inoculated into a culture medium for fermentation culture.

8. A method for preparing a freeze-dried powder containing the *Bacillus diazoxide* of claim 1, the method comprising: The diazotrophic plantarum described in claim 1 is fermented and then freeze-dried with the addition of a protective agent to prepare freeze-dried powder.

9. The use of the diazoxide-eating plantar bacillus according to claim 1, or the bacterial preparation according to any one of claims 2-6, in the preparation of formulations for degrading benzene series compounds; in, The benzene compounds are selected from one or more of benzene, toluene, ethylbenzene, and xylene.

10. A method for degrading benzene compounds, the method comprising: Contact the diazoxide-eating plant bacillus according to claim 1, or the bacterial preparation according to any one of claims 2-6, with the sample or environment of the benzene series compounds to be degraded; The benzene compounds are selected from one or more of benzene, toluene, ethylbenzene, and xylene.

11. The method according to claim 10, wherein, The sample of the benzene series compounds to be degraded is a water body, and the method includes adding the diazoxide-eating Bacillus plantarum of claim 1 or the bacterial preparation of any one of claims 2-6 into the water body.

12. The method according to claim 10, wherein, The environment in which the benzene series compounds to be degraded are indoor air environments. The method includes preparing a bacterial solution from the *Bacillus diazoxide-eating* of claim 1 or the bacterial preparation of any one of claims 2-6, and then either irrigating it in the soil, spraying it on the surface of indoor objects, or using it in conjunction with a small aerodynamic device; or placing flower nutrient soil containing the *Bacillus diazoxide-eating* of claim 1 in the environment in which the benzene series compounds to be degraded are placed.

13. The method according to claim 12, wherein, The potting soil for flowers contains plants.

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