Enterobacter hallii and its application

Abstract

The present invention belongs to the field of microbial treatment technology, and specifically relates to a strain of Enterobacter hollandii and its application, which has the ability to efficiently dissolve Fe from iron tailings. 2+ / 3+ , Ca 2+ Mg 2+ The functional strain is used to treat coastal saline soil. The dissolved free metal ions can accurately target the Na + , by virtue of ion exchange, Na + Desorption and discharge of cultivated soil from saline soil bodies can effectively improve the high salinity and single composition problems of coastal saline soil, and provide advanced and reliable technical means for the ecological restoration and agricultural utilization of coastal saline soil.

Description

Technical Field

[0001] The present invention belongs to the field of microbial treatment technology, and specifically relates to a strain of Enterobacter holmii and its application, and in particular to a strain with the ability to efficiently dissolve Fe from iron tailings. 2+ / 3+ , Ca 2+ Mg 2+ Functional bacteria that absorb high-valent metal cations such as cations, and based on soil colloid adsorption and ion replacement, achieve efficient treatment of coastal saline soil. Background Art

[0002] Coastal saline soil, a subtype of salinized soil, refers to soils containing salt throughout their entire profile, formed by the action of ocean tides or high-concentration groundwater. Widely distributed in coastal areas worldwide, it is characterized by its wide distribution, large existing area, high degree of salinization, and rapid growth, making it a pressing issue for land resource utilization and the ecological environment. In recent years, driven by global climate change, increasing seawater intrusion, and irrational human activities, the area of ​​coastal saline soil has been increasing at an average annual rate of approximately 0.5-1%, severely restricting ecological protection, agricultural development, and economic development in coastal areas.

[0003] Coastal saline soils are characterized by high salt content throughout the soil, primarily composed of NaCl and Na2SO4. Therefore, traditional methods for improving saline-alkali soils are not fully applicable. For example, freshwater flushing methods are inefficient and require significant water resources. Chemical treatments can pollute surrounding water bodies through surface runoff and soil infiltration. Traditional biological improvement methods are not suitable for high-salt wastelands and tidal flats. Iron tailings, rich in valuable metals such as Fe, Ca, and Mg, have great potential for replacing soil sodium salts, promoting salt leaching, and migrating to deeper layers. Furthermore, as a potential resource for improving coastal saline soils, iron tailings have a significant stockpile volume and annual growth rate. Therefore, if iron tailings can be rationally utilized, they could potentially be transformed into a reliable resource for improving coastal saline soils, achieving a synergistic solution for improving coastal saline soils and achieving high-value utilization of iron tailings.

[0004] The main factor restricting the application of iron tailings in coastal saline soil improvement is the difficulty in efficiently utilizing the high-valent metal elements such as Fe, Ca, and Mg contained in them. First, the complex mineral structure, tight crystal structure, and high chemical bond energy of iron tailings make it difficult for Fe, Ca, and Mg ions to easily escape from the lattice and dissolve. At the same time, the three-dimensional network structure of associated minerals such as silicates and carbonates significantly impedes the dissolution of high-valent metal ions. Second, the lack of suitable dissolution technology is also a key factor. Existing technologies, such as traditional acid leaching, not only have energy consumption issues but are also unsuitable for in-situ application in coastal saline soil. Microbial dissolution technology, due to its long-term effectiveness, no secondary pollution, in-situ application, and simultaneous soil microecological improvement, can play a key role in coastal saline soil improvement when used in conjunction with iron tailings. However, as an emerging technology approach, microbial enhancement of iron tailings for coastal saline soil improvement cannot yet meet the needs of practical applications due to the difficulty in finding functional bacteria that are both tolerant to the harsh high-salt environment and can efficiently dissolve metals. Summary of the Invention

[0005] The purpose of the present invention is to provide a strain of Enterobacter holliformis and its application, which has the ability to efficiently dissolve Fe from iron tailings and the problem of low utilization efficiency of high-valent metal elements such as Fe, Ca, and Mg in the application of iron tailings in coastal salt soil treatment. 2 + / 3+ , Ca 2+ Mg 2+ Functional bacteria that absorb high-valent metal cations such as cations, and based on soil colloid adsorption and ion replacement, achieve efficient treatment of coastal saline soil.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect of the present invention, a strain is provided, characterized in that the strain is classified and named Enterobacter hormaechei H9, and is deposited in the China Center for Type Culture Collection on December 12, 2024, with a deposit number of CCTCC NO: M 20242800.

[0008] The present invention uses a functional selection culture medium that retains only the basic carbon source, nitrogen source and buffer system, and replaces the trace element components with iron tailings powder as the enrichment condition. Samples are taken from the rhizosphere soil of the artificially designed culture and acclimation system. Through multi-stage enrichment and separation and purification, a salt-tolerant strain with the ability to efficiently dissolve Fe from iron tailings is screened. 2+ / 3+ , Ca 2+ Mg 2+ Functional microbial strains of high-valent metals (Enterobacter holmii H9, Enterobacter hormaechei H9 ).

[0009] Enterobacter hallii H9 is a facultative anaerobic, Gram-negative bacterium that forms white, round colonies with smooth, moist surfaces on standard beef extract-peptone agar. It exhibits good growth at pH values ​​between 5 and 9, tolerates NaCl growth within a range of ≤ 8% (w / v), and exhibits an OD 600 (9 h) exceeding 0.19.

[0010] The strain has the ability to efficiently dissolve Fe from iron tailings. 2+ / 3+ , Ca 2+ Mg 2+ The functional strain is used to treat coastal saline soil. The dissolved free metal ions can accurately target the Na + , by virtue of ion exchange, Na + Desorption and discharge of cultivated soil from saline soil bodies can effectively improve the high salinity and single composition problems of coastal saline soil, and provide advanced and reliable technical means for the ecological restoration and agricultural utilization of coastal saline soil.

[0011] A second aspect of the present invention provides a microbial agent containing the aforementioned Enterobacter hallii.

[0012] Furthermore, it includes bacterial strains, bacterial liquid or fermentation liquid.

[0013] The third aspect of the present invention provides the use of the above-mentioned microbial agent in dissolving high-valent metal ions in iron tailings.

[0014] Furthermore, the high-valent metal ions include at least one of iron ions, calcium ions and magnesium ions.

[0015] The functional microbial strain of the present invention is used to treat iron tailings in a liquid culture medium environment. 2 + / 3+ , Ca 2+ Mg 2+ The initial concentrations were 0.25-0.32, 27.96-29-34, and 2.39-2.41 μg·mL -1 , inoculated with Enterobacter holmii H9 ( Enterobacter hormaechei H9 ), the concentrations of different high-valent metal ions increased rapidly. At the 9th hour after inoculation, Fe 2+ / 3+ , Ca 2+ Mg 2+ The concentrations were 12.10-13.42, 55.55-60.32, and 9.99-11.42 μg·mL, respectively. -1 , reaching a peak at the 24th hour, reaching 14.67-16.60, 64.84-70.11 and 13.03-14.54 μg·mL -1 .

[0016] A fourth aspect of the present invention provides the use of the above-mentioned microbial agent in the treatment of coastal saline soil.

[0017] Furthermore, the treatment of coastal saline soil includes promoting the discharge of salt from the coastal saline soil.

[0018] Furthermore, the treatment of coastal saline soil includes reducing the total salinity of coastal saline soil.

[0019] The functional microorganisms of the present invention were used to enhance the improvement of coastal saline soil by iron tailings. Iron tailings were added to the coastal saline soil at a ratio of 10% (w / w) and the iron tailings were added at a ratio of 5 mL·kg -1 The ratio of spraying Enterobacter holmesii H9 ( Enterobacter hormaechei H9 ) solution, and simulated natural precipitation was used for irrigation. The original total salt content of the tillage layer (0-20 cm depth) was 4.17-4.47 g·kg -1 After treatment with this technology, it can be reduced to 2.03-2.39 g·kg -1 ; The original sodium ion content is 787.08-838.62 mg·kg -1 After the application of this technology, it can be reduced to 277.38-338.01 g·kg -1 ; The original free iron content is 0.29-0.39 mg·kg -1 After the application of this technology, it can be increased to 1.81-4.31 mg·kg -1 The Fe / Na ratio increased from 0.0004 to 0.0053-0.0155; the Ca / Na ratio increased from 0.5958 to 0.8825-0.9165. The principle of the present invention is that the bio-enhanced dissolution of high-valent metals in iron tailings leads to the formation of Fe 2+ / 3+ , Ca 2+ etc. for Na + The replacement of Fe in the soil further promotes the discharge of salt and the reduction of total salinity. 2+ / 3+ The significant increase in Fe / Na content, Fe / Na ratio, and Ca / Na ratio can not only promote the improvement of coastal saline soil, but also promote its further utilization.

[0020] A fifth aspect of the present invention provides a method for dissolving high-valent metal ions in iron tailings, using the above-mentioned microbial agent for treatment.

[0021] In a sixth aspect, the present invention provides a method for treating high salinity in coastal saline soil, wherein iron tailings and the above-mentioned microbial agent are added to the coastal saline soil to treat the soil.

[0022] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0023] 1. The present invention relates to a strain of Enterobacter holmii and its application, which has the ability to efficiently dissolve Fe from iron tailings. 2 + / 3+ , Ca 2+ Mg 2+ The functional strain is used to treat coastal saline soil. The dissolved free metal ions can accurately target the Na + , by virtue of ion exchange, Na + Desorption and discharge of cultivated soil from saline soil bodies can effectively improve the high salinity and single composition problems of coastal saline soil, and provide advanced and reliable technical means for the ecological restoration and agricultural utilization of coastal saline soil.

[0024] 2. The present invention utilizes iron tailings as the main material for improvement technology, which not only realizes the efficient management of coastal saline soil, but also applies a large amount of iron tailings to the restoration of saline-alkali land in view of the current characteristics of large iron tailings reserves, rapid production, and low utilization rate, thereby realizing the two-way coupling of large-scale solid waste resource utilization and large-scale coastal saline soil improvement.

[0025] 3. The main material used in this invention is iron tailings, which is rich in Fe, Ca, Mg and other elements, which can replace Na in the soil with relatively low exchange performance. + , which is beneficial to Na + 、Cl - and SO4 2- The soluble salt ions migrate to the underlying soil, eventually reducing the salinity of coastal saline soil.

[0026] 4. This invention utilizes independently selected functional microbial strains to enhance the improvement of coastal saline soils from iron tailings. This approach offers advantages such as low cost and simple processing. The strains are prone to survival and proliferation in the soil, and their effects are long-lasting. The strain employed, Enterobacter hallii, is widely distributed in soils and has been shown in relevant studies to promote plant growth and improve soil nutrient cycling. This approach can achieve long-term restoration of coastal saline soils and synchronize microecological ecosystem regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The colony appearance and development tree diagram ( Figure 1 The a in the figure is a picture of the strain under an optical microscope after Gram staining. Figure 1 b in the figure is a colony picture. Figure 1 (c in the figure is a phylogenetic tree).

[0028] Figure 2This is the OD600 value data graph of Enterobacter hallii H9 in pH (bar graph) and salinity (line graph) gradient culture medium.

[0029] Figure 3 The free Fe in the functional verification medium (iron tailings leachate) 2+ / 3+ ( Figure 3 a) in Ca 2+ ( Figure 3 b) in Mg 2+ ( Figure 3 c) Graph showing the temporal variation of ion concentration.

[0030] Figure 4 Schematic diagram of the verification device for microbial enhancement of iron tailings to improve coastal saline soil.

[0031] Figure 5 This is a data chart showing the contents of eight major salt ions in the improved soil.

[0032] Figure 6 is the Fe content in the soil after improvement ( Figure 6 a), Fe / Na ratio ( Figure 6 b) and Ca / Na ratio ( Figure 6 c) Data graph in . DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to the accompanying drawings.

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Example

[0035] Screening, identification and preservation of strains

[0036] Establishment of functional selection culture medium:

[0037] The functional selection medium for screening microbial strains capable of dissolving high-valent metals from iron tailings has a specific formula of: glucose 10.0 g·L -1 , peptone 5.0 g·L -1 , iron tailings (200 mesh) 2.0 g·L -1 、NaCl8.0 g·L -1 、KCl 0.2 g·L -1 、Na2HPO4 g·L -1 、KH2PO4 g·L -1Place the functional selection medium in a high-temperature steam sterilizer, set the temperature to 121°C for 30 minutes, cool to room temperature, and then adjust the pH value to 7.0 with NaOH and HCl solution for later use.

[0038] Establishment of artificial cultivation and domestication system:

[0039] Wheat was planted using coastal saline soil (collected from Gudao Town, Dongying City, Shandong Province, 118.42'58'' E, 37.48'59'' N. Soil sampling was performed at a depth of 0-30 cm, removing rocks, plant and animal debris, and other debris. Properties are shown in Table 1 ), iron tailings (collected from the Gongchangling Iron Tailings Dump, Liaoyang City, Liaoning Province, 123.03'26'' N, 41.02'56'' N. Samples were collected at a depth of 0-30 cm. Element distribution is shown in Table 2 ). A commercially available nutrient matrix soil was mixed in a 1:1:1 ratio. Pots were removed on the 90th day after planting, and the rhizosphere soil was collected.

[0040] Table 1 Basic properties of the tested coastal saline soil

[0041]

[0042] Table 2 Basic properties of the tested iron tailings

[0043]

[0044] a. Enrichment culture: After collecting rhizosphere soil, place 5.0 g of soil into a 250 mL conical flask containing 100 mL of functional selection medium. Set the temperature to 30 °C and the rotation speed to 120 rpm. -1 , cultured in a shaking incubator for 12 hours;

[0045] b. Plate culture and purification: Diethylpyrocarbonate treated water (DEPC water) was used to culture the bacterial solution at 10 -1 -10 -9 Perform serial dilutions, inoculating 100 μL of the dilution into a culture dish, spreading evenly with an L-shaped applicator, and incubating at 37°C for 3 days. After incubation, pick a single colony with a 1 μL inoculating loop and continue to isolate and purify the bacteria on beef extract peptone agar plates multiple times. After each purification, incubate at 37°C for 3 days until a single colony is visible to the naked eye on the plate.

[0046] c. Preservation of bacterial strains: Pick a single colony and inoculate it into 5 mL of Luria-Bertani medium (Solarbio, Product No. L1010) using a 1 μL inoculation loop. Then, incubate at 37°C and 120 rpm for 1 h. -1After culturing for 12 hours, add 800 μL of culture medium to a 2 mL sterile cryopreservation tube, add 200 μL of sterile glycerol (80% v / v), mix well, and store in a -80°C refrigerator. Meanwhile, store the single colony on the plate in a 4°C refrigerator.

[0047] d. Bacteria identification:

[0048] Take an appropriate amount of bacterial cells and add them to a 2mL centrifuge tube. Add 567 μL of TE buffer and repeatedly pipette to resuspend. Then add 30 μL of 10% SDS and 15 μL of proteinase K and mix thoroughly. Incubate at 55°C for 30 minutes. Add an equal volume of chloroform:isoamyl alcohol solution (24:1 volume ratio) and centrifuge at 12,000 rpm for 4-5 minutes. Then, transfer the supernatant to a fresh tube and add 0.6-0.8 times the volume of isopropanol. Gently mix until the DNA precipitates and centrifuge at 12,000 rpm for 10 minutes. Wash with 1 mL of 70% ethanol and centrifuge at 12,000 rpm for 10 minutes. Discard the ethanol. Dry in a clean bench and resuspend in 50 μL of TE buffer or deionized water.

[0049] The sequenced strains were identified by SeqMan splicing, vector sequence removal and chimera detection, and compared and classified at the National Center for Biotechnology Information (NCBI). A total of 1 bacterial strain, Enterobacter hallii H9 ( Enterobacter hormaechei H9 )belong Enterobacter It is a facultative anaerobic bacterium with Gram-negative properties. It grows on ordinary beef extract-peptone agar medium to form white, round colonies with smooth and moist surfaces. Figure 1 shown.

[0050] 16S rRNA sequence:

[0051]

[0052] Preservation of functional microorganisms:

[0053] Enterobacter hallii H9 ( Enterobacter hormaechei H9 ) has been deposited with the China Center for Type Culture Collection (CCTCC), located at 299 Bayi Road, Wuchang District, Wuhan City, Hubei Province, Wuhan University, under accession number CCTCC M20242800, and the date of deposit is December 12, 2024. In the laboratory, long-term storage of the strain is achieved by inoculating it in MB 2216 medium (Difco, Catalog No. 279110) containing 30% glycerol and storing it at -80°C. Short-term storage is achieved by inoculating the strain onto slants on beef extract peptone agar and storing it at 4°C until needed.

[0054] Example 2

[0055] Experiment on growth tolerance of strains to pH and salinity

[0056] Salinity gradient culture medium configuration:

[0057] Using salt-free Luria-Bertani medium as the basis, NaCl was added thereto to obtain a total of 8 salinity gradient culture media with salinity of 0, 1, 2, 3, 4, 5, 6, and 7% (w / v), respectively. The pH value was 7.0. The culture media were sterilized in a high-temperature steam sterilizer at 121°C for 30 min and cooled for later use.

[0058] The salt-free Luria-Bertani medium has the following formula: peptone 10 g·L -1 Yeast extract 5.0 g·L -1 , pH 7.0.

[0059] pH gradient medium configuration:

[0060] Using standard Luria-Bertani medium (Solarbio, Cat. No. L1010) as the base, adjust the pH with 5 M NaOH or 2 M HCl to obtain eight pH gradients of 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0. Sterilize in a high-temperature steam autoclave at 121°C for 30 min and cool until ready for use.

[0061] Growth tolerance experiment of salinity and pH value:

[0062] Enterobacter holmii H9 ( Enterobacter hormaechei H9 ) was frozen in glycerol (Example 1) and inoculated into salinity gradient and pH gradient culture medium at a ratio of 1% (v / v). Three replicates were set for each gradient. The culture medium was incubated at 30°C and 120 r·min-1 The culture was carried out for 9 hours, and the OD value of the bacterial solution was measured to record the growth of the strain ( Figure 2 ).

[0063] The experimental results showed that Enterobacter hallii H9 showed good growth ability at pH values ​​of 5-9, with OD600 reaching 0.20-0.42 after 9 hours of culture. Growth was also observed when the amount of NaCl added was less than 8, with OD600 exceeding 0.19. Example

[0064] Experiment on the promotion of high-valent metal ion dissolution from iron tailings by bacterial strains

[0065] Establishment of culture medium for dissolution of high-valent metal ions from solid waste:

[0066] The functional verification medium for verifying the efficacy of the microbial strain in dissolving high-valent metals from iron tailings is specifically formulated as follows: glucose 10.0 g·L -1 , peptone 5.0 g·L -1 , iron tailings (100 mesh) 2.0 g·L -1 、NaCl 8.0g·L -1 、KCl 0.2 g·L -1 、Na2HPO4 g·L -1 、KH2PO4 g·L -1 Place the functional selection medium in a high-temperature steam sterilizer, set the temperature to 121°C for 30 minutes, cool to room temperature, and then adjust the pH value to 7.0 with NaOH and HCl solution for later use.

[0067] Establishment of functional verification experimental system:

[0068] This implementation case is divided into experimental group 1 and control group, a total of 2 groups.

[0069] Experimental group 1 was to use Enterobacter holmii H9 ( Enterobacter hormaechei H9 ) was inoculated into the above-mentioned functional verification medium (250 mL Erlenmeyer flask, containing 100 mL of medium liquid) at a ratio of 1% (v / v) and set up 3 replicates. The culture medium was stirred at 30 °C and 120 r·min -1 The mixture was cultured for 7 days to obtain an iron tailings dissolution solution.

[0070] The control group was a function verification culture medium without inoculation of functional microorganisms.

[0071] Determination of dissolution efficiency (high-valent metal ion concentration):

[0072] The enhanced effect of functional strains on the dissolution of high-valent metal ions in iron tailings was measured by the free Fe 2+ / 3+ , Ca 2+ Mg 2+ Ion concentration performance. At the 9th hour, 1st, 3rd, 5th, and 7th day of culture, 10 mL of liquid was collected and the culture medium was heated at 4 °C and 8000 r·min. -1 After centrifugation for 10 min, the supernatant was collected and passed through a 0.45 μm water-based polyethersulfone filter membrane and a C18 column in sequence to remove suspended particulate impurities and organic matter, respectively. Finally, the supernatant was diluted 5 times with 2.5% HNO3 and the Fe content was determined according to the national environmental protection standard method "Determination of 32 elements in water by inductively coupled plasma optical emission spectrometry" (HJ 776-2015). 2+ / 3+ , Ca 2+ Mg 2+ concentration.

[0073] Evaluation of dissolution efficiency:

[0074] Enterobacter hallii H9 ( Enterobacter hormaechei H9 ) for Fe in iron tailings 2+ / 3+ , Ca 2+ Mg 2+ All showed good leaching efficiency (such as Figure 3 ). In the functional verification culture medium, Fe 2+ / 3+ , Ca 2+ Mg 2+ The initial concentrations were 0.25-0.32, 27.96-29-34, and 2.39-2.41 μg·mL -1 The control group never showed significant differences. After inoculation with EH and PM strains, the concentrations of different high-valent metal ions increased rapidly. At the 9th hour of inoculation, the concentrations of Fe in the experimental group 1 and experimental group 2 increased significantly. 2+ / 3+ , Ca 2+ Mg 2+ The concentrations were 12.10-13.42, 55.55-60.32, and 9.99-11.42 μg·mL, respectively. -1 , reaching a peak at the 24th hour, which were 14.67-16.60, 64.84-70.11 and 13.03-14.54 μg·mL -1 . Example

[0075] Experiment on improving coastal saline soil by microbial enhancement of iron tailings

[0076] Soil column verification test materials and equipment:

[0077] The locations for collecting coastal saline soil and iron tailings for testing were the same as those in Example 1. Representative soil profiles were selected, and soil from the 0-20 cm and 20-40 cm layers was collected for soil column experiments. The soil from the same layer was thoroughly mixed and air-dried, then passed through a 4 mm sieve and loaded into the soil column. Enterobacter hormaechei H9 ) were cultured in Luria-Bertani medium (Solarbio, Product No. L1010) for 10 h, and then rotated at 3000 r·min -1 The cells were centrifuged at 4 °C for 10 min to obtain the cells, which were then washed three times with 0.01 M sodium dihydrogen phosphate buffer (PBS) and then redissolved and adjusted to 10 8 The concentration of CFU / mL.

[0078] The soil column experiment was conducted using a transparent acrylic glass column with an inner diameter of 20 cm and a height of 40 cm. A 1 cm diameter hole was reserved at the bottom of each soil column to facilitate the drainage of leachate. First, a 5 cm thick quartz sand layer was placed as a filter layer to prevent soil at the bottom of the column from clogging the column outlet. Then, a layer of nylon mesh was evenly laid on the quartz sand in each column. Based on the actual bulk density of the soil at the sampling site (1.4 g cm -3 ), weigh the required 30 cm high-salinity soil, and mix or spray the above iron tailings and bacterial solution into the soil according to the experimental design. After mixing evenly, fill the soil column evenly. Fill each soil column 6 times, 5 cm each time, and reserve a 5 cm water storage layer above the soil column (such as Figure 4 shown).

[0079] This implementation case is divided into experimental group 1, experimental group 2 and control group, a total of 3 groups.

[0080] Experimental group 1 was to add iron tailings to coastal saline soil at a ratio of 10% (w / w) and fill the soil column;

[0081] Experimental group 2 was to add iron tailings to the coastal saline soil at a ratio of 10% (w / w) and at the same time add 5 mL·kg -1 The ratio of spraying Enterobacter holmesii H9 ( Enterobacter hormaechei H9 ) bacterial solution and fill the soil column;

[0082] The control group was simply filled with the same mass of coastal saline soil as that of the experimental groups without any other treatment.

[0083] Testing and analysis of the efficiency of microbial enhanced iron tailings improvement:

[0084] To simulate salt leaching from natural precipitation, an intermittent leaching method was used. Leaching was performed every 12 hours, with 300 mL of leaching water added each time. The experiment lasted for 21 days. A soil sensor (SN-3001-TRREC-Ⅱ, Jinan Jiande Kelun Technology Co., Ltd.) was inserted into the middle of the soil column, and a data logger (RS-TREC-N01-1-Ⅱ, Jinan Jiande Kelun Technology Co., Ltd.) was connected to the end of the soil sensor to store data. pH and conductivity were monitored every 24 hours. After the experiment, the soil was removed from the soil column, naturally dried in the shade, and thoroughly mixed. The exchangeable base ion content (K) of the soil was determined according to the "Determination of Cation Exchange Capacity and Exchangeable Base of Neutral Soils" (NY / T 295-1995). + 、Na + , Ca 2+ Mg 2+ ); Refer to "Soil Testing Part 18: Determination of Soil Sulfate Ion Content" (NY / T 1121.18-2006) to determine the soil sulfate ion content (SO4 2- ); Refer to "Soil Testing Part 17: Determination of Soil Chloride Content" (NY / T 1121.17-2006), determine the chloride ion content in the soil (Cl - ) content; refer to "Analysis of Water-Soluble Salt in Forest Soil" (LY / T 1251-1999), determine the content of carbonate (CO3 2- ) and bicarbonate (HCO3 - ) ion content; refer to the "Determination of Available Iron, Manganese, Copper and Zinc in Soil - Inductively Coupled Plasma Mass Spectrometry" (DB12 / T 1269-2023), "Determination of Available Iron in Forest Soil" (LY / T 1262-1999), and "Determination of Free Iron in Soil - Inductively Coupled Plasma Emission Spectrometry" (T / HNNMIA 86-2023) to determine the content of free iron ions in the soil.

[0085] Evaluation of the efficiency of microbial enhanced iron tailings improvement:

[0086] Adding iron tailings and leaching with simulated precipitation to the soil column of coastal saline soil reduced the total salt content and improved the salt ion composition to a certain extent, while the inoculation of two functional microorganisms further enhanced this process (e.g. Figure 5 and Figure 6 The bio-enhanced dissolution of high-valent metals in iron tailings leads to the formation of Fe 2+ / 3+ , Ca 2+ etc. for Na + The replacement of Fe in the soil further promotes the discharge of salt and the reduction of total salinity. 2+ / 3+The significant increase in Fe / Na content, Fe / Na ratio, and Ca / Na ratio can not only promote the improvement of coastal saline soil, but also promote its further utilization.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An Enterobacter holmii, characterized in that The strain was classified and named Enterobacter hormaechei H9 and deposited in the China Center for Type Culture Collection on December 12, 2024, with the deposit number CCTCCNO: M 20242800.

2. A microbial agent containing the Enterobacter hallii according to claim 1.

3. The microbial agent according to claim 2, characterized in that Including strains, bacterial liquid or fermentation liquid.

4. The use of the microbial agent as claimed in claim 2 in dissolving high-valent metal ions in iron tailings, characterized in that: The high-valent metal ion is selected from at least one of trivalent iron ions, calcium ions and magnesium ions.

5. Use of the microbial agent as claimed in claim 2 in the treatment of coastal saline soil.

6. The use according to claim 5, characterized in that The purpose of controlling coastal saline soil is to promote the discharge of salt from coastal saline soil.

7. The use according to claim 5, characterized in that The purpose of controlling coastal saline soil is to reduce the total salinity of coastal saline soil.

8. A method for dissolving high-valent metal ions in iron tailings, characterized in that: The microbial agent according to claim 2 is used for treatment, and the high-valent metal ions are selected from at least one of trivalent iron ions, calcium ions and magnesium ions.

9. A method for controlling salt in coastal saline soil, characterized in that: Iron tailings and the microbial agent as claimed in claim 2 are added to coastal saline soil to treat the soil.

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