Prussella adamsii with multifunctional environment restoration capability and application of Prussella adamsii

Abstract

The invention discloses a strain of P.adami with multifunctional environment restoration capability and application thereof, and belongs to the technical field of microorganisms. According to the invention, a P.aryabhattai strain is screened from soil of mining wasteland in a manganese ore area and belongs to Priesta aryabhattai, and tests prove that the strain can oxidize manganese to form a biological manganese oxide, can move, is resistant to acid, alkali and high salt, has moderate biofilm production capacity, and can be used for preparing a biofilm. The composite material can generate hydrogen sulfide, adsorb and remove heavy metals (Cd and Pb), degrade polycyclic aromatic hydrocarbon (phenanthrene) and promote plant growth, and can be applied to water and soil to achieve the purposes of removing Cd, Pb and phenanthrene and promoting plant growth.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, and particularly relates to a Priestia aryabhattai strain with multifunctional environmental remediation ability and its application. Background Art

[0002] The rapid development of industrialization and urbanization has led to an increasing accumulation of pollutants such as heavy metals and polycyclic aromatic hydrocarbons in the environment. Among numerous heavy metal elements, Cd and Pb often co-occur and are prone to cause combined pollution. Polycyclic aromatic hydrocarbons are listed as priority control pollutants due to their high toxicity and persistence. These pollutants can be enriched through the food chain, leading to health risks such as cancer, nerve damage, and immune system disorders. In recent years, the excessive use of chemical fertilizers and pesticides, as well as the unreasonable discharge of livestock manure and industrial wastewater, have caused a sharp decline in soil quality and increasingly serious soil-borne diseases, greatly affecting the quality and yield of crops and even triggering environmental degradation problems.

[0003] Therefore, it is urgent to reduce heavy metal and organic pollution and improve soil quality. Although traditional physicochemical remediation technologies (such as chemical leaching, pyrolysis adsorption, ion exchange, etc.) can quickly remove pollutants, they have drawbacks such as high cost, secondary pollution, and damage to soil microbial communities, making it difficult to be applied on a large scale in complex environments (such as mining areas, industrial waste lands). Microbial remediation technology has become a research hotspot due to its environmental friendliness, low cost, and sustainability. Microorganisms can effectively remove heavy metals and organic substances through mechanisms such as adsorption, precipitation, redox, or degradation. For example, some Bacillus sp. adsorb heavy metals by secreting extracellular polymeric substances (EPS), and Pseudomonas sp. degrades polycyclic aromatic hydrocarbons through oxygenase. However, existing functional microorganisms generally have the following limitations: (1) Single function: Most strains only target a single pollutant (such as adsorbing cadmium or degrading phenanthrene), making it difficult to deal with the widespread multiple pollution problems in the actual environment. (2) Poor environmental adaptability: Extreme environments (such as high salt, acidic, or alkaline conditions) will significantly inhibit the activity of microorganisms. (3) Insufficient colonization ability: The motility and biofilm formation ability of microorganisms directly affect their migration and colonization efficiency at pollution sites. Strains lacking motility or biofilm formation ability are difficult to survive stably in heterogeneous soils or waters. (4) Lack of plant growth-promoting characteristics (such as producing indole acetic acid, siderophores), and unable to form a synergistic remediation system with plants. Therefore, the development of microorganisms with multiple functions has become the research focus for reducing heavy metal and organic pollution and improving soil quality. Summary of the Invention

[0004] In view of the above-mentioned prior art, the object of the present invention is to provide a Priestia aryabhattai strain with multifunctional environmental remediation capabilities and its applications. The present invention screened a Priestia aryabhattai strain XT78 from the soil of a manganese mining waste land. It has been experimentally proven that this strain can oxidize manganese to form biological manganese oxides, can move, tolerate acids, bases and high salts, and has a medium ability to produce biofilms. It can produce hydrogen sulfide, adsorb and remove heavy metals (Cd, Pb), degrade polycyclic aromatic hydrocarbons (phenanthrene), and promote plant growth. It can be applied to water bodies and soils to achieve the purpose of removing Cd, Pb, phenanthrene and promoting plant growth.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In the first aspect of the present invention, a Priestia aryabhattai strain XT78 is provided. This strain was deposited at the China Center for Type Culture Collection (abbreviated as CCTCC, address: Wuhan University, Luojia Hill, Wuchang, Hubei) on April 27, 2025, and its biological deposit number is: CCTCC NO: M 2025911.

[0007] Compared with the previously reported Priestia aryabhattai strains, the main characteristics of the Priestia aryabhattai strain XT78 of the present invention are as follows:

[0008] (1) It can oxidize manganese to form biological manganese oxides;

[0009] (2) It has strong environmental adaptability and can tolerate acid, base and high salt stresses;

[0010] (3) It has adsorption and degradation effects on various heavy metals and organic pollutants;

[0011] (4) It can move, has motility and swarming ability, which enables the strain to survive stably in heterogeneous soils or water bodies;

[0012] (5) It has the ability to produce biofilms, which can improve soil quality.

[0013] (6) It has the ability to produce ammonia, IAA and siderophores, and can promote crop growth.

[0014] Therefore, the Priestia aryabhattai strain XT78 of the present invention combines multiple functions and has broad application prospects in reducing heavy metal and organic pollution and improving soil quality.

[0015] In a second aspect of the present invention, a bacterial agent is provided, which contains the above-mentioned Priestia aryabhattai XT78.

[0016] Preferably, in the bacterial agent, Priestia aryabhattai XT78 exists in the form of cultured viable bacteria, bacterial suspension or fermentation broth.

[0017] Furthermore, the bacterial suspension is prepared by the following method:

[0018] Inoculate Priestia aryabhattai XT78 into LB liquid medium and culture it at 35 °C and 150 r / min for 12 h. Centrifuge the culture solution, and resuspend the bacterial cell precipitate with sterile water to obtain the bacterial suspension.

[0019] Furthermore, in addition to containing Priestia aryabhattai XT78, the bacterial agent may also include excipients or carrier matrices, etc.; such as trehalose, glucose, carboxymethyl cellulose, dextrin, soluble starch, peat, diatomite.

[0020] The dosage form of the bacterial agent can be liquid agent, emulsion, suspending agent, powder, granule, wettable powder or water dispersible granule.

[0021] In a third aspect of the present invention, the above-mentioned Priestia aryabhattai XT78 or bacterial agent is provided for use in improving soil quality.

[0022] Priestia aryabhattai XT78 of the present invention has medium biofilm-forming ability. The formation of biofilm can improve soil structure, increase soil air permeability and water holding capacity, thereby improving soil quality and providing a more favorable environment for plant growth.

[0023] In a fourth aspect of the present invention, the above-mentioned Priestia aryabhattai XT78 or bacterial agent is provided for use in the following (1) or (2):

[0024] (1) Removing residual polycyclic aromatic hydrocarbons in the environment;

[0025] (2) Preparing a product for removing residual polycyclic aromatic hydrocarbons in the environment.

[0026] Preferably, the polycyclic aromatic hydrocarbon is phenanthrene.

[0027] The fifth aspect of the present invention provides the application of the above-mentioned Priestia aryabhattai XT78 or the bacterial agent in the following (1) or (2):

[0028] (1) Remediating heavy metal pollution in the environment;

[0029] (2) Preparing a product for remediating heavy metal pollution in the environment.

[0030] Preferably, the heavy metal pollution is Cd pollution and Pb pollution.

[0031] The sixth aspect of the present invention provides the application of the above-mentioned Priestia aryabhattai XT78 or the bacterial agent in promoting plant growth and development.

[0032] In the above application, the Priestia aryabhattai XT78 or the bacterial agent promotes plant growth and development through at least one of the following pathways:

[0033] (1) Producing ammonia;

[0034] (2) Producing auxin;

[0035] (3) Producing siderophores.

[0036] Advantages of the present invention:

[0037] The Priestia aryabhattai XT78 of the present invention can oxidize 100 mmol / L Mn at a high concentration 2+ to form biological manganese oxides for environmental remediation, can perform movements such as swimming and swarming, tolerate acids and alkalis (pH = 5-9) and high salts (1%-7%), and has a medium ability to produce biofilms; can degrade phenanthrene, and the degradation rate of 10 mg / L phenanthrene reaches 68.30% within 72 h; can efficiently adsorb and remove Cd and Pb, the removal rate of 2.5 mg / L Cd reaches 97.79% within 48 h, and the removal rate of 400 mg / L Pb reaches 75.06% within 48 h; and can produce substances such as ammonia, auxin, and siderophores, and has the effect of promoting plant growth.

[0038] The Priestia aryabhattai XT78 of the present invention can tolerate acids and alkalis, high salts and produce biofilms, integrating the functions of adsorbing and removing heavy metals Cd and Pb in water bodies and soils, degrading polycyclic aromatic hydrocarbon phenanthrene, producing biological manganese oxides, and promoting plant growth. It is a multifunctional strain and has broad application prospects. Description of the Drawings

[0039] Figure 1 This is the colony morphology diagram of the strain XT78 of the present invention.

[0040] Figure 2 This is the scanning electron microscope image of the strain XT78 of the present invention.

[0041] Figure 3 This is the phylogenetic tree diagram of the strain XT78 of the present invention.

[0042] Figure 4 This is the result diagram of the ability of the strain XT78 of the present invention to produce biological manganese oxides.

[0043] Figure 5 This is the result diagram of the growth density of the strain XT78 of the present invention under different pH conditions.

[0044] Figure 6 This is the result diagram of the growth density of the strain XT78 of the present invention under different salinity conditions.

[0045] Figure 7 This is the result diagram of the motility test of the strain XT78 of the present invention.

[0046] Figure 8 This is the result diagram of the swarming test of the strain XT78 of the present invention.

[0047] Figure 9 This is the result diagram of the hydrogen sulfide production test of the strain XT78 of the present invention.

[0048] Figure 10 This is the result diagram of the biofilm production of the strain XT78 of the present invention.

[0049] Figure 11 This is the result diagram of the ammonia production ability of the strain XT78 of the present invention.

[0050] Figure 12 This is the result diagram of the auxin production ability of the strain XT78 of the present invention.

[0051] Figure 13 This is the result diagram of the siderophore production ability of the strain XT78 of the present invention. Detailed implementation manners

[0052] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0053] To enable those skilled in the art to more clearly understand the technical solution of this application, the technical solution of this application will be described in detail below in combination with specific embodiments. If the specific experimental conditions are not specified in the embodiments, they are usually in accordance with conventional conditions or the conditions recommended by reagent companies; for the reagents, consumables, etc. used in the following embodiments, unless otherwise specified, they can all be obtained through commercial channels. Among them:

[0054] LB liquid medium: 10.0 g of NaCl, 10.0 g of peptone, 5.0 g of yeast extract, 1000 mL of distilled water, adjust the pH to 7.0, and autoclave at 121 °C for 20 min.

[0055] LB solid medium: 10.0 g of NaCl, 10.0 g of peptone, 5.0 g of yeast extract, 15 g of agar powder, 1000 mL of distilled water, adjust the pH to 7.0, and autoclave at 121 °C for 20 min.

[0056] LB medium containing Mn 2+ : 10.0 g of NaCl, 10.0 g of peptone, 5.0 g of yeast extract, 1000 mL of distilled water, adjust the pH to 7.0, and autoclave at 121 °C for 20 min. After sterilization, add 1000 mmol / L Mn 2+ mother liquor filtered and sterilized with a 0.22 μm microporous filter membrane to make the final concentration of Mn 2+ 100 mmol / L.

[0057] Inorganic salt medium: 2000 mg of sucrose, 2800 mg of Na2HPO4, 1000 mg of KH2PO4, 500 mg of (NH4)2SO4, 53 mg of MgCl2, 50 mg of Ca(NO3)2·4H2O, C 10 H 14 N2Na2O8 0.5 mg, 0.2 mg of FeSO4·7H2O, 0.01 mg of ZnSO4·7H2O, 0.003 mg of MnCl2·4H2O, 0.03 mg of H3BO3, 0.02 mg of CoCl2·6H2O, 0.001 mg of CuCl2·2H2O, 0.002 mg of NiCl2·6H2O, 0.003 mg of H4MoNa2O6, 1000 mL of deionized water, adjust the pH to 7.0, autoclave at 121 °C for 20 min.

[0058] Salkowski's color reagent: 30 mL of concentrated sulfuric acid, 1.5 mL of 0.5 mol / L FeCl3·6H2O solution, dissolved in 50 mL of deionized water.

[0059] Peptone ammonification medium: 5 g of peptone, 1000 mL of deionized water, pH 7.2, sterilized at 121 °C for 20 min.

[0060] Example 1: Isolation and identification of strains

[0061] 1. Isolation of strains:

[0062] Manganese-oxidizing bacteria were isolated from the soil near the abandoned manganese mine in Xiangtan City, Hunan Province. The collected soil was cultured by the liquid culture method.

[0063] Take 5 g of soil and add it to 50 mL of LB medium containing Mn 2+ . Incubate in a constant temperature shaker at 35 °C and 150 r / min for 2 d. Use the plate culture method for isolation and preservation, and number and store in a 4 °C refrigerator.

[0064] Inoculate the preserved purified strain into LB solid medium and streak to isolate single colonies. Pick a single colony into liquid LB medium and incubate at 35 °C and 150 r / min in a constant temperature shaker until its logarithmic growth phase. Centrifuge and wash the culture solution twice with sterile water and resuspend the bacterial cells to obtain a bacterial suspension (OD 600 ≈ 0.8). Inoculate the bacterial suspension into LB medium containing Mn 2+ at an inoculation amount of 2% (v / v). Use the LB medium containing Mn 2+ without adding the bacterial solution as a control, and shake culture for 48 h to detect the content of biological manganese oxides (BMOs).

[0065] Take 0.5 mL of the cultured solution after incubation, add 1 mL of 0.04% LBB color reagent. Observe the color change from light blue to dark blue to qualitatively detect the biological manganese oxides in the sample. After qualitative detection by LBB, determine the strain with the strongest ability to produce BMOs and name it XT78.

[0066] 2. Identification of strains:

[0067] (1) Morphological identification:

[0068] Observe the colony morphology of the obtained strain XT78 ( Figure 1 ). The main biological characteristics of this strain are: the colony is yellowish-white, regular in shape and round, with neat edges, bulging in the middle, relatively viscous, and growing densely and vigorously. Observe the strain XT78 under a SEM scanning electron microscope at 10.0K ( Figure 2 ). The cells are rod-shaped, with blunt ends, about 2 microns in length and about 1 micron in diameter; usually single, and sometimes short chain-like arrangements can be seen (such as 2 cells connected).

[0069] (2) Molecular biological identification:

[0070] The 16S rDNA of strain XT78 was amplified by PCR, and the PCR amplification product was sequenced by Shanghai Personal Biotechnology Co., Ltd. The sequence of its 16S rDNA is shown in SEQ ID NO.1.

[0071] The 16S rDNA sequencing result of strain XT78 was uploaded to GenBank for Blast analysis to construct a phylogenetic tree ( Figure 3 ), and it was found that strain XT78 had the highest similarity with Priestia aryabhattai B8W22 and was in the same branch.

[0072] Based on the comprehensive identification results of morphology and molecular biology, strain XT78 was identified as Priestia aryabhattai. The isolated and screened Priestia aryabhattai XT78 was deposited in the China Center for Type Culture Collection, and the deposit information is as follows:

[0073] Biological material (strain) cited: XT78;

[0074] Proposed taxonomic name: Priestia aryabhattai;

[0075] Registration number: CCTCC NO: M 2025911;

[0076] Deposit date: April 27, 2025.

[0077] Example 2: Preparation of Priestia aryabhattai XT78 bacterial suspension

[0078] A single colony of Priestia aryabhattai XT78 was inoculated into 50 mL of LB liquid medium and cultured at 35 °C and 150 r / min for 12 h. The culture solution was centrifuged, and the bacterial precipitate was washed three times with sterile water. Then, the cell concentration was adjusted to OD 600 = 0.8 with sterile water to prepare a Priestia aryabhattai XT78 bacterial suspension.

[0079] Example 3: Manganese oxidation performance test of Priestia aryabhattai XT78

[0080] The Priestia aryabhattai XT78 bacterial suspension prepared in Example 2 was inoculated into 50 mL of LB medium containing Mn 2+ at an inoculum size of 2% (v / v), and cultured in the dark at 35 °C and 150 r / min in a shaker. The Mn-containing 2+LB medium was used as a control. Samples were taken on the 7th day. 0.5 mL of the cultured broth was taken and 1 mL of 0.04% LBB color reagent was added to observe the color change for qualitative detection of biological manganese oxides in the samples. After qualitative detection with LBB ( Figure 4 ), it was found that the culture product of strain XT78 had an obvious color reaction, changing from light blue to dark blue, indicating that strain XT78 could produce biological manganese oxides.

[0081] Example 4: Physiological and biochemical tests of Priestia aryabhattai XT78

[0082] 1. Acid-base and salt tolerance tests of strain XT78

[0083] (1) Acid-base tolerance performance:

[0084] HCl and NaOH solutions were used to adjust the pH value of LB liquid medium to pH = 5, 6, 7, 8, 9 respectively to obtain media with different acid-base degrees.

[0085] The strain XT78 bacterial suspension prepared in Example 2 was inoculated into 50 mL of sterilized LB medium with different pH values at an inoculation amount of 2% (v / v), and cultured in a shaker at 35 °C and 150 r / min in the dark. LB liquid medium without bacteria was used as a control, and samples were taken at 24 h. The absorbance value OD at 600 nm was measured using a spectrophotometer 600 .

[0086] The results are as Figure 5 shown. The results indicate that strain XT78 grew well within pH = 5 - 9, had relatively good acid-base tolerance performance, and the optimal pH was 7.

[0087] (2) Salt tolerance performance:

[0088] In LB liquid medium, different concentrations of NaCl solutions were added to make the salinity 1%, 3%, 5%, 7%, 9%. The strain XT78 bacterial suspension prepared in Example 2 was inoculated into 50 mL of sterilized LB medium with different salinities at an inoculation amount of 2% (v / v), and cultured in a shaker at 35 °C and 150 r / min in the dark. LB liquid medium without bacteria was used as a control, and samples were taken at 24 h. The absorbance value OD at 600 nm was measured using a spectrophotometer 600 .

[0089] The results are as Figure 6 shown. Strain XT78 grew well within the salinity of 1% - 7%, could tolerate high salinity, and the optimal salinity was 3%.

[0090] 2. Motility test of strain XT78

[0091] Prepare LB solid media with agar concentrations of 0.3% and 0.7% and sterilize them. The LB solid media with 0.3% agar concentration is used to measure the motility of the strain, and the LB solid media with 0.7% agar concentration is used to measure the swarming motility of the strain. Place the two concentrations of LB solid media in a laminar flow hood and dry for 30 min. Then concentrate the bacterial suspension of strain XT78 prepared in Example 2 by 10 times, and take 10 μL and drop it into the LB solid media with 0.3% agar concentration and the LB solid media with 0.7% agar concentration respectively. Make observation records at 48 h, and use a ruler to measure the motility diameter D. As Figure 7 、 Figure 8 shown, after 48 h of culture, it was observed that the strain XT78 changed from a drop to a cloudy turbid circle. The motility diameters D of strain XT78 were 1.8 cm and 2.0 cm > 1 cm respectively, indicating that strain XT78 has motility and swarming motility and can move.

[0092] 3. Test for H2S production by strain XT78

[0093] Take 10 μL of the bacterial suspension of strain XT78 prepared in Example 2 and inoculate it into the sterilized lead acetate solid medium (HaiBo Biotechnology Co., Ltd., Qingdao High-Tech Industrial Park), and place it in a constant temperature incubator at 30 °C for 48 h. Judge whether H2S is produced by whether PbS precipitate is generated.

[0094] As Figure 9 shown, a dark brown PbS precipitate appeared in the center of the bacteria XT78, proving that strain XT78 can produce H2S during growth. Strains that produce H2S have significant application potential in the fields of heavy metal immobilization, organic matter degradation, wastewater treatment, etc. through mechanisms such as sulfide precipitation, microbial adsorption, and metabolic synergy.

[0095] Example 5: Test for biofilm production by Priestia aryabhattai XT78

[0096] Dilute the bacterial suspension of strain XT78 prepared in Example 2 by 100 times, and add 200 μL per well to a 96-well plate. Incubate statically at 30 °C for 2 d, wash twice with PBS to remove unadsorbed bacteria, and air dry naturally. Add 100 μL of 0.1% crystal violet staining solution to each well, and perform staining treatment for 30 min. Aspirate the crystal violet staining solution, wash off the surface floating color with PBS, and air dry. Then add 200 μL of 95% ethanol, let stand for 15 min to dissolve the crystal violet, and analyze the biofilm content by detecting the absorbance value (As) at 590 nm of the sample. Use the LB medium without adding the bacterial suspension of strain XT78 as a control and perform the same treatment, denoted as LB(Ac).

[0097] Based on the OD value generated by bacterial biofilms at 590 nm, the ability of bacteria to form biofilms was evaluated as follows: If As ≤ Ac, there is no function of biofilm production; if Ac < As ≤ (2×Ac), there is a low biofilm production ability; if (2×Ac) < As ≤ (4×Ac), there is a medium biofilm production ability; if (4×Ac) < As, there is a strong biofilm production ability.

[0098] The results are as Figure 10 shown, and the strain XT78 has a medium biofilm production ability at 48 h.

[0099] Example 6: Test on the adsorption and removal of heavy metals Cd and Pb by Priestia aryabhattai XT78

[0100] The strain XT78 bacterial suspension prepared in Example 2 was inoculated into 50 mL of LB liquid medium containing 2.5 mg / L Cd 2+ (or 400 mg / L Pb 2+ ) at an inoculation amount of 2% (v / v), and cultured in the shaker at 35 °C and 150 r / min in the dark. The LB liquid medium containing Cd 2+ (or Pb 2+ ) without bacteria was used as a control, and samples were taken at 24 and 48 h respectively. After filtration with 0.22 μm, the content of Cd (or Pb) was measured by ICP, and the heavy metal removal rate was calculated.

[0101] Calculation of heavy metal removal rate:

[0102] In the formula: x: the removal rate of strain XT78 (%); C X : the concentration of heavy metal (Cd or Pb) in the inoculated culture solution; C CK : the concentration of heavy metal (Cd or Pb) in the non-inoculated control culture solution.

[0103] The results are shown in Table 1. As time goes by, the removal rates of heavy metals Cd and Pb by strain XT78 continuously increase, reaching 97.79% and 75.06% respectively at 48 h. Therefore, it shows that the strain has an efficient effect on the adsorption and removal of heavy metals.

[0104] Table 1: Test results of the adsorption and removal of heavy metals by strain XT78

[0105]

[0106] Example 7: Test on the degradation of polycyclic aromatic hydrocarbon phenanthrene by Priestia aryabhattai XT78

[0107] Degradation of phenanthrene by strain XT78: The strain XT78 suspension prepared in Example 2 was inoculated with 2% (v / v) inoculum into 50 mL of an inorganic salt medium with a phenanthrene concentration of 10 mg / L. The culture time was set to 72 h, pH was 7.0, and the culture was carried out in a constant temperature incubator at 35°C and 150 r / min. Samples were taken and measured on time. 1.5 mL of sample was taken with a pipette, and centrifuged at 4°C and 8000 rpm for 5 minutes using a high-speed centrifuge. The solution was then sterilized with a disposable syringe. Filter through an organic filter membrane, pipette the sample into a brown sampling bottle, wait for measurement and record the data, and calculate the phenanthrene degradation rate.

[0108] Determination of phenanthrene: Agilent high performance liquid chromatograph was used to determine the concentration of phenanthrene. The detection conditions were: C18 column (5 μm, 250 mm × 4.6 mm), UV detector, detection wavelength of 254 nm, temperature of 25 °C, acetonitrile: ultrapure water (80:20) as mobile phase, flow rate of 1.5 mL / min, injection volume of 5 μL. The degradation rate of phenanthrene was calculated.

[0109] Calculation of the degradation rate of phenanthrene:

[0110] Where: x: degradation rate of strain XT78 (%); C X : the concentration of phenanthrene in the inoculated culture medium; C CK : The concentration of phenanthrene in the uninoculated control culture medium.

[0111] Using methanol (chromatographic grade) as solvent, prepared gradient concentrations of phenanthrene standard solutions of 1, 2.5, 5, 7.5, 10 mg / L, respectively, were injected under the selected liquid chromatography conditions, and the phenanthrene concentration was used as the horizontal axis and the peak area as the vertical axis to draw a phenanthrene standard curve. Its linear equation is y=118.69x-1.575, and the correlation coefficient is 0.9996, indicating that the concentration of phenanthrene and its peak area have a good linear relationship.

[0112] The results are shown in Table 2. At 72 hours, the degradation rate of strain XT78 for 10 mg / L phenanthrene reached 68.30%, indicating that strain XT78 has a high efficiency in degrading phenanthrene.

[0113] Table 2: Test results of degradation of PAHs by strain XT78

[0114]

[0115] Example 8: Test on the performance of Priesteria axyri XT78 in promoting plant growth

[0116] (1) Determination of ammonia production capacity

[0117] Take 10 μL of the bacterial suspension of strain XT78 prepared in Example 2 and inoculate it into the peptone ammonification medium. Use the peptone ammonification medium without inoculation as a control. Repeat each treatment 2 times. Incubate at 28 ± 2 °C with shaking at 180 rpm for 5 days. After the incubation, centrifuge at 10,000 rpm for 10 min. Add 1 mL of Nessler's reagent to the supernatant and observe the change of the solution. If orange or yellow precipitate is produced, it indicates that the strain has the ability to produce ammonia.

[0118] The results are as Figure 11 shown in Table 3. Strain XT78 has a strong ability to produce ammonia, indicating that strain XT78 has deaminase, which can cause the deamination reaction of amino acids to generate ammonia and various acids, thus being beneficial to the growth and development of plants.

[0119] (2) Determination of the ability to produce auxin

[0120] Take 10 μL of the bacterial suspension of strain XT78 prepared in Example 2 and inoculate it into the LB liquid medium containing 5 mmol / L tryptophan. Use the LB liquid medium containing 5 mmol / L tryptophan without inoculation as a control. Repeat each treatment 2 times. Incubate at 28 ± 2 °C with shaking at 180 rpm for 2 days. After the incubation, centrifuge at 10,000 rpm for 10 min. Take 1 mL of the supernatant, add an equal volume of Salkowski's color reagent, and let it stand in the dark for 30 min to develop the color of the culture solution. Then observe the change of the solution color. If the solution turns pink, it indicates that the strain has the ability to produce auxin, and the darker the color, the stronger the ability of the strain to produce auxin.

[0121] The results are as Figure 12 shown in Table 3. Strain XT78 has a relatively strong ability to produce auxin, which is beneficial to promoting the growth and development of plants.

[0122] (3) Determination of the ability to produce siderophores

[0123] Take 10 μL of the bacterial suspension of strain XT78 prepared in Example 2 and inoculate it into the sterilized CAS detection solid medium (Haibo Biotechnology Co., Ltd., Qingdao High-tech Industrial Park). Incubate it in a constant temperature incubator at 35 °C for 48 h, and then observe and record the test results.

[0124] The results are as Figure 13 shown in Table 3. The color of the medium around strain XT78 changes from blue to orange-yellow, and a yellow ring appears, which is the siderophore secretion circle. Therefore, strain XT78 can produce siderophores, which is beneficial to promoting the growth and development of plants.

[0125] Table 3: Test results of strain XT78 promoting plant growth

[0126]

[0127] Note: "+" indicates a positive reaction. The more "+", the stronger the ability to produce ammonia, auxin, and siderophore.

[0128] In summary, the multifunctional strain XT78 is a strain that can oxidize manganese to form biological manganese oxides, can move, tolerate acids and alkalis and high salts, and has a medium ability to produce biofilms. It can produce hydrogen sulfide, adsorb and remove heavy metals (Cd, Pb), degrade polycyclic aromatic hydrocarbons (phenanthrene), and promote plant growth.

[0129] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A strain of Priestia aryabhattai XT78, with the preservation number of CCTCC NO: M2025911.

2. A bacterial agent, characterized in that, The bacterial agent contains the Priestia aryabhattai XT78 described in claim 1.

3. The bacterial agent according to claim 2, characterized in that, In the bacterial agent, the Priestia aryabhattai XT78 exists in the form of cultured live bacteria, bacterial suspension or fermentation broth.

4. The microbial agent according to claim 3, characterized in that, The bacterial suspension is prepared by the following method: Inoculate Priestia aryabhattai XT78 into LB liquid medium, culture it at 35 °C and 150 r / min for 12 h, centrifuge the culture solution, and resuspend the bacterial cell precipitate with sterile water to obtain the bacterial suspension.

5. The microbial agent according to claim 2, characterized in that, The dosage form of the bacterial agent is liquid agent, emulsion, suspending agent, powder, granule, wettable powder or water dispersible granule.

6. The application of the Priestia aryabhattai XT78 described in claim 1 or the bacterial agent described in any one of claims 2 - 5 in improving soil quality.

7. The application of the Priestia aryabhattai XT78 described in claim 1 or the bacterial agent described in any one of claims 2 - 5 in the following (1) or (2): (1) Removing polycyclic aromatic hydrocarbons remaining in the environment; (2) Preparing a product for removing polycyclic aromatic hydrocarbons remaining in the environment; Preferably, the polycyclic aromatic hydrocarbon is phenanthrene.

8. The application of the Priestia aryabhattai XT78 described in claim 1 or the bacterial agent described in any one of claims 2 - 5 in the following (1) or (2): (1) Remediating heavy metal pollution in the environment; (2) Preparing a product for remediating heavy metal pollution in the environment; Preferably, the heavy metal pollution is Cd pollution and / or Pb pollution.

9. The application of the Priestia aryabhattai XT78 described in claim 1 or the bacterial agent described in any one of claims 2 - 5 in promoting plant growth and development.

10. The application according to claim 9, characterized in that, The Priestia aryabhattai XT78 or the bacterial agent promotes plant growth and development through at least one of the following pathways: (1) Producing ammonia; (2) Producing auxin; (3) Producing siderophore.

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