Microbial agent and application thereof in arsenic pollution remediation

Abstract

The application discloses a kind of microbial inoculant and its application in arsenic pollution repair, the microbial inoculant includes humic acid reducing bacteria and humic acid, humic acid reducing bacteria is any one of Shewanella oneidensis MR-1 or Geobacter sulfurreducens, humic acid is any one of soil humic acid, water humic acid or coal humic acid.The microbial inoculant prepared by the application is loaded on humic acid by humic acid reducing bacteria, utilizes aerobic-anaerobic dynamic change, periodically generates ·OH, efficiently oxidizes As (III) to As (V) or organic arsenic, and also utilizes ·OH to promote carbonization reaction of humic acid to generate graphite carbon, further enhancing the adsorption and fixation effect of arsenic, without additional oxidizing agent, green and economical, realizing the synergistic effect of microorganisms and humic acid, realizing arsenic oxidation and graphite carbon adsorption integration, with high and lasting repair efficiency.

Description

Technical Field

[0001] This invention relates to the technical field of environmental biology and pollution control, specifically to a microbial agent that can efficiently oxidize and fix arsenic and its application in the remediation of arsenic-contaminated environments. Background Technology

[0002] Arsenic pollution is a major global environmental problem, particularly originating from mining, smelting, and pesticide use. The main forms of arsenic in the environment include trivalent arsenic (As(III)), pentavalent arsenic (As(V)), and organic arsenic (MMA and DMA). Trivalent arsenic is the most toxic and exhibits high mobility and bioavailability, while pentavalent and organic arsenic are less toxic. Therefore, converting highly toxic trivalent arsenic into less toxic pentavalent and organic arsenic and achieving arsenic fixation is a key focus and challenge in the remediation of arsenic-contaminated environments.

[0003] Currently, arsenic pollution control technologies mainly include physical, chemical, and biological methods. Physical methods primarily involve adsorption, which often uses activated carbon and metal oxides. Adsorption is effective for As(V), but its adsorption capacity for As(III) is limited, usually requiring pre-oxidation treatment. Chemical methods mainly include chemical precipitation and chemical oxidation. Chemical precipitation involves adding iron or aluminum salts to precipitate arsenic, but the large dosage can easily cause soil compaction and water salinization. Chemical oxidation uses strong oxidants such as Fenton's reagent, potassium permanganate, and ozone to oxidize As(III) to As(V). While effective, it suffers from high chemical costs, secondary pollution (e.g., iron sludge from the Fenton process), poor environmental adaptability, and potential adverse effects on soil and biological communities. Biological methods mainly rely on the oxidation, adsorption, or methylation processes of microorganisms. For example, arsenic-oxidizing bacteria can be used to oxidize As(III) to As(V), but under natural conditions, this is inefficient and slow. Although microbial remediation is environmentally friendly, it has obvious limitations: (1) low abundance and insufficient activity of natural microbial communities; (2) poor stability of free microbial environment and easy loss; (3) the remediation effect is greatly affected by environmental conditions (pH, temperature, nutrients, etc.).

[0004] Therefore, developing a microbial agent that can achieve both efficient and continuous oxidation of arsenic and good adsorption and fixation of arsenic is of great practical significance for the remediation of arsenic-contaminated environments. Summary of the Invention

[0005] The purpose of this invention is to provide a microbial agent and its application in the remediation of arsenic pollution.

[0006] According to a first aspect of the present invention, a microbial agent is provided, comprising humic acid reducing bacteria and humic acid, wherein the humic acid reducing bacteria is any one of Shewanella oneidensis MR-1 or Geobacter sulfurreducens, and the humic acid is any one of soil humic acid, water humic acid or coal humic acid.

[0007] In some embodiments, humic acid accounts for 50% to 70% of the mass of the above-mentioned microbial agent, and the content of humic acid-reducing bacteria in the above-mentioned microbial agent is 10. 6 ~10 9 cfu / g.

[0008] According to a second aspect of the present invention, a method for preparing a microbial inoculant is provided, comprising the following steps: S1. Inoculate humic acid-reducing bacteria into anaerobic culture medium and culture until OD. 600 =0.6~1.0, centrifuge to collect bacterial cells, and resuspend in sterile phosphate buffer to a bacterial concentration of 10. 8 ~10 9 A bacterial suspension of humic acid-reducing bacteria was prepared by using cfu / g. S2. Grind the humic acid, sieve it, rinse it with deionized water to remove soluble impurities, and dry it to obtain pretreated humic acid; S3. In an anaerobic glove box, the humic acid pretreated in step S2 is mixed with the bacterial suspension prepared in step S1 at a mass-to-volume ratio of 1:20. After sealing, the mixture is shaken and cultured. After the culture is completed, the solid material is collected by centrifugation under anaerobic conditions, rinsed, and the unattached bacteria are removed to obtain a microbial agent. The agent is then stored in a wet state in an anaerobic bag at 4°C for later use.

[0009] In some embodiments, in step S1, humic acid-reducing bacteria are inoculated at a volume ratio of 1.5%, and the anaerobic fermentation medium comprises the following components: 2.5 g / L sodium bicarbonate, 0.25~1.5 g / L ammonium chloride, 0.1~0.5 g / L yeast extract, and 20 mM sodium lactate. The anaerobic culture conditions are 30~60℃ and the anaerobic culture time is 36~96 hours. In step S2, the sieve mesh size is 150 mesh, the drying temperature is 60℃, and the drying time is 12 hours. In step S3, the shaking culture conditions are 25~60℃, and the shaking culture time is 24~48 hours.

[0010] According to a third aspect of the present invention, the application of the above-described microbial agent or a microbial agent prepared by the above-described method in the remediation of arsenic pollution is provided.

[0011] According to a fourth aspect of the present invention, a method for remediating arsenic pollution in water is provided. The method comprises: mixing a microbial agent or a microbial agent prepared by the above method with arsenic-polluted water to construct an oxidation-reduction cycle treatment system, continuously oxidizing trivalent arsenic contained in the arsenic-polluted water, and taking samples at the end of each cycle to determine the remediation status of the arsenic-polluted water.

[0012] In some implementations, microbial agents are mixed with arsenic-contaminated water at a mass ratio of 1-5:995-999, and the oxidation-reduction cycle treatment system creates an aerobic or anaerobic environment by continuously introducing air or high-purity N2 into the system.

[0013] In some implementations, each cycle of the oxidation-reduction cycle treatment system is anaerobic followed by aerobic, with the anaerobic period lasting 18-48 hours and the aerobic period lasting 6-24 hours. The reaction temperature of the oxidation-reduction cycle treatment system is 30-60°C, and the continuous reaction time of the oxidation-reduction cycle treatment system is 4-10 cycles.

[0014] According to a fifth aspect of the present invention, a method for remediating arsenic pollution in soil is provided. The method comprises: mixing a microbial agent or a microbial agent prepared by the above method with arsenic-contaminated soil, performing dry-wet alternating treatment to construct an oxidation-reduction cycle treatment system, continuously oxidizing trivalent arsenic in the arsenic-contaminated soil, and taking samples before the end of the aerobic period of each cycle to determine the remediation status of the arsenic-contaminated soil.

[0015] In some implementations, microbial agents are mixed with arsenic-contaminated soil at a mass ratio of 1-5:995-999. The oxidation-reduction cycle treatment system creates aerobic and anaerobic environments by alternating drying and flooding of the arsenic-contaminated soil. In each cycle of the oxidation-reduction cycle treatment system, the drying period is 1-3 days and the flooding period is 2-6 days. The continuous reaction time of the oxidation-reduction cycle treatment system is 8-20 cycles.

[0016] The beneficial effects of this invention are as follows: The microbial agent prepared by this invention contains humic acid-reducing bacteria and humic acid. By loading specific humic acid-reducing bacteria onto a humic acid carrier, the aerobic-anaerobic dynamic changes in the environment are utilized to periodically generate ·OH, which efficiently oxidizes As(III) to As(V) or organic arsenic. Furthermore, ·OH is used to promote the carbonization reaction of humic acid, generating graphite carbon, which further enhances the adsorption and fixation effect on arsenic, significantly reducing the toxicity and migration of arsenic. No external oxidant is required, making it green and economical. This invention achieves synergistic effects between microorganisms and humic acid, integrating arsenic oxidation and graphite carbon adsorption, resulting in high and long-lasting remediation efficiency. Attached Figure Description

[0017] Figure 1This is a scanning electron microscope (SEM) characterization image of the microbial agent of Example 1 of the present invention.

[0018] Figure 2 This is a comparison chart of the ·OH content in each cycle of the arsenic-contaminated water remediation process between the experimental group and the control group in Example 3 of the present invention.

[0019] Figure 3 This is a comparison chart of the changes in the content of different forms of arsenic between the experimental group and the control group during the remediation of arsenic-contaminated water in Example 3 of the present invention. Figure 3 A is a comparison chart of the dynamic changes in As(III) content; Figure 3 B is a comparison chart of the dynamic changes in As(V) content; Figure 3 C is a comparison chart of the dynamic changes in the content of organic arsenic (MMA and DMA).

[0020] Figure 4 This is a graph showing the changes in the proportion of different forms of arsenic during the remediation of arsenic pollution in water by microbial agents in the experimental group of Example 3 of the present invention.

[0021] Figure 5 This is a graph showing the change in ·OH content during the remediation of soil arsenic pollution by the microbial inoculant of Example 4 of the present invention.

[0022] Figure 6 The images shown are optical microscopy and Raman spectroscopy characterizations of humic acid after soil arsenic pollution remediation in Example 4 of the present invention. Figure 6 A is a diagram of the carbonized humic acid region under an optical microscope; Figure 6 B is the Raman spectral characterization of the humic acid carbonization region.

[0023] Figure 7 This is a graph showing the changes in the content and proportion of different forms of arsenic during the soil arsenic pollution remediation process in Example 4 of the present invention. Figure 7 A shows the changes in the content of arsenic in different forms; Figure 7 B is a graph showing the changes in the proportion of different forms of arsenic during the four cycles of the remediation process. Detailed Implementation

[0024] The present invention is further described in detail through specific implementation examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. After reading this invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims. Unless otherwise specified, all raw materials and reagents of the present invention are commercially available.

[0025] Example 1

[0026] A method for preparing a microbial inoculant includes the following steps: S1. A humic acid-reducing bacterium, *Shewanella oneidensis* MR-1, was isolated and screened from paddy soil (collected from Fuzhou, Fujian). This humic acid-reducing bacterium was identified as *Shewanella oneidensis* MR-1 by 16S rRNA inoculation into anaerobic medium (composition: NaHCO3 2.5 g / L, NH4Cl 0.25 g / L, yeast extract 0.5 g / L, sodium lactate 20 mM, pH 6.8-7.2) at a volume ratio of 1.5% and cultured in an anaerobic incubator at 30℃ for 36 hours until OD (digestive oxygen saturation). 600 =1.0, centrifuge at 8000 rpm for 10 min, collect the bacterial cells, and resuspend in sterile phosphate buffer (PBS, 0.1 M, pH 7.0) to a bacterial concentration of 10. 9 CFU / mL was used to obtain a bacterial suspension of humic acid-reducing bacteria; S2. Take 10.0 g of humic acid, grind it and pass it through a 150-mesh sieve. Rinse it three times with deionized water to remove soluble impurities. Dry it at 60℃ for 12 hours to obtain pretreated humic acid. S3. In an anaerobic glove box (N2 atmosphere, O2 < 0.1%), 10.0 g of the pretreated humic acid from step S2 was mixed with 200 mL of the Shewanella oneidensis MR-1 bacterial suspension prepared in step S1 in a 500 mL Erlenmeyer flask. After sealing, the flask was placed on a shaker and cultured at 120 rpm for 24 hours at 30–60 °C. After the culture was completed, the solid material was collected by centrifugation at 4000 rpm for 5 min under anaerobic conditions. The solid material was gently washed three times with PBS buffer to remove unattached bacteria and obtain a microbial agent. The agent was then stored in a wet state in an anaerobic bag at 4 °C for later use.

[0027] The prepared microbial inoculants were observed by scanning electron microscopy. Specific results are shown in [link to relevant documentation]. Figure 1 .like Figure 1 As shown, in the microbial agent prepared in this embodiment, the humic acid-reducing bacterium Shewanella oneidensis MR-1 is effectively loaded onto the surface of humic acid, with a unit loading of 10 on the carrier (humic acid). 8 cfu / g.

[0028] Example 2

[0029] A method for preparing a microbial inoculant includes the following steps: S1. A humic acid-reducing bacterium, *Geobacter sulfurreducens*, was isolated and screened from paddy soil (collected from Fuzhou, Fujian). This bacterium was identified as *Geobacter sulfurreducens* by 16S rRNA. The *Geobacter sulfurreducens* strain was inoculated at a volume ratio of 1.5% into anaerobic medium (composition: NaHCO3 2.5 g / L, NH4Cl 1.5 g / L, yeast extract 0.1 g / L, NaH2PO4 0.6 g / L, KCl 0.1 g / L, sodium lactate 20 mM, sodium fumarate 40 mM, L-cysteine ​​hydrochloride 0.5 g / L, vitamin mixture 10 mL / L, trace element solution 10 mL / L, pH 6.8-7.2) and cultured in an anaerobic incubator at 30℃ for 72 hours until OD (digestive tract growth) reached. 600 =0.6, centrifuged at 8000 rpm for 10 min, collected the bacterial cells, washed twice with pre-reduced anaerobic phosphate buffer (PBS, 0.1 M, pH 7.0, containing 1 mM cysteine) and resuspended to a bacterial concentration of 10. 9 CFU / mL was used to obtain a bacterial suspension of humic acid-reducing bacteria; S2. Take 10.0 g of humic acid, grind it and pass it through a 150-mesh sieve. Rinse it three times with deionized water to remove soluble impurities. Dry it at 60℃ for 12 hours to obtain pretreated humic acid. S3. In an anaerobic glove box (N2 atmosphere, O2 < 0.1%), 10.0 g of the pretreated humic acid from step S2 was mixed with 200 mL of the Geobacter sulfurreducens bacterial suspension prepared in step S1 in a 500 mL Erlenmeyer flask. An induction solution containing the following components was added: 20 mM sodium acetate, 30 mM NaHCO3, 0.25 g / L NH4Cl, and 0.5 mM L-cysteine. The flask was sealed and placed on a shaker. It was cultured at 120 rpm for 36–48 hours at 25–30 °C. After the culture was completed, the solid material was collected by centrifugation at 4000 rpm for 10 min under anaerobic conditions. The solid material was gently washed three times with PBS buffer to remove unattached bacteria, and a microbial agent was obtained. The agent was stored in a wet state in an anaerobic bag at 4 °C for later use.

[0030] Example 3: Remediation of Arsenic-Contaminated Water by Microbial Agents

[0031] 3.1 Preparation of Simulated Arsenic-Contaminated Water: Simulated groundwater was prepared using deionized water with the following basic components: CaCl2 0.5 mM, MgSO4 0.5 mM, NaHCO3 2 mM, pH 7.2 ± 0.1. NaAsO2 was added to the simulated groundwater as the arsenic source to achieve an initial As(III) concentration of 75.0 ± 0.1 mg / L, thus obtaining the simulated arsenic-contaminated water body.

[0032] 3.2 Experimental Design: Two parallel experiments were set up, an experimental group and a control group, both conducted in 250 mL glass reactors, with a working volume of 150 mL for each group. Experimental group: Microbial inoculant prepared in Example 1 was added to a final concentration of 2.0 g / L; Control group: Simulated arsenic-contaminated water was used without the addition of microbial inoculant. Each group had three replicates.

[0033] 3.3 Remediation Process for Arsenic-Contaminated Water: The reactors of the experimental and control groups were subjected to anaerobic conditions for 48 hours to ensure that the adsorption of arsenic by the microbial agent prepared in Example 1 reached equilibrium. After adsorption equilibrium, an automatic control system was used to continuously introduce air or high-purity N2 into the reactor periodically to construct an oxidation-reduction cycle system. Each cycle was 72 hours: the first 48 hours were the anaerobic period, during which high-purity N2 was continuously introduced into the reactor at a flow rate of 0.2 L / min to ensure that DO in the system was <0.2 mg / L; the following 24 hours were the aerobic period, during which air was introduced into the reactor at a flow rate of 0.5 L / min to aerate the system and make DO >6.0 mg / L. The reactors of both the experimental and control groups were run at a constant temperature of (30±1)℃ for 4 cycles (a total of 288 hours). Samples were taken at the end of each cycle, filtered through a 0.22 μm filter membrane, and the water quality was measured.

[0034] 3.4 Water quality testing and results

[0035] 3.4.1 During the remediation process of arsenic-contaminated water bodies described in 3.3, water samples were taken during both the aerobic and anaerobic phases of each cycle. Coumarin was immediately added as a ·OH scavenging agent, and the ·OH content in the water samples was determined by measuring the fluorescence intensity of 7-hydroxycoumarin using a microplate reader. Specific results are shown in [link to results]. Figure 2 .

[0036] like Figure 2 As shown, compared with the control group, the experimental group produced a large amount of ·OH in the redox cycle system, and the production of ·OH showed obvious periodicity.

[0037] 3.4.2 High-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was used to determine the arsenic speciation (As(III), As(V), DMA, and MMA) in the water sample taken in 3.3. Specific results are shown in [link to results]. Figure 3 .

[0038] Changes in the content of different forms of arsenic during the reaction process, such as Figure 3 A~ Figure 3 As shown in Figure C, the As(III) content in the experimental group continued to decrease, and the rate of decrease was faster during the aerobic period. The contents of As(V), DMA, and MMA continued to increase, indicating that the microbial agent prepared in Example 1 effectively oxidized As(III), realized the speciation of arsenic in the water, and remediated the arsenic pollution in the water. In addition, the As(III) content in the control group did not change significantly, and no large amounts of As(V), DMA, and MMA were produced, indicating that the arsenic pollution in the water without the addition of the microbial agent prepared in Example 1 was not remediated.

[0039] 3.4.3 According to Figure 3 A~ Figure 3 Data from C further analyzes the remediation effect of microbial agents on arsenic in water bodies; specific results can be found in [link to data]. Figure 4 .

[0040] Figure 4 It is based on Figure 3 The results show the proportions of different forms of arsenic, where the adsorbed arsenic is calculated by subtracting the initial arsenic content from the adsorbed arsenic content. Figure 3 The total amount of arsenic detected in the sample is used. For example... Figure 4 As shown, the addition of the microbial agent prepared in Example 1 to the water body of the experimental group effectively reduced the proportion of As(III). After four cycles of continuous reaction, As(III) accounted for only 21% of the total arsenic. Most of the arsenic was adsorbed or oxidized into As(V), DMA and MMA, which are less toxic. This effectively reduced the toxicity and bioavailability of arsenic in the water body, achieved the remediation of arsenic-polluted water bodies, and reduced environmental risks.

[0041] Example 4: Remediation of Arsenic-Contaminated Soil by Microbial Inoculants

[0042] 4.1 Preparation of arsenic-contaminated soil: Paddy soil from surrounding farmland was collected, and NaAsO2 solution was added to make the total arsenic concentration reach 75 mg / kg (of which As(III) accounted for 70%), and aged for 30 days.

[0043] 4.2 Experimental design: Add 5.0 g of the microbial agent prepared in Example 1 (i.e., 1% w / w) to 500 g of arsenic-contaminated soil, mix evenly, and repeat 3 times.

[0044] 4.3 Arsenic-Contaminated Soil Remediation Process: Arsenic-contaminated soil was placed in plastic basins and subjected to a "dry-wet alternation" cycle treatment to construct an oxidation-reduction cycle treatment system. Each cycle included a drying period and a flooding period. The drying period involved natural drainage for one day to create an aerobic environment. The flooding period involved maintaining a water layer of 3-5 cm for two days to create an anaerobic environment. This cycle was repeated for a total of four cycles (12 days). Samples were taken during both the drying and flooding periods of each cycle, freeze-dried, ground, and sieved through a 100-mesh sieve for later use.

[0045] 4.4 Detection and Results

[0046] 4.4.1 Soil samples were taken during the flooding and drying periods of each cycle in the remediation process of arsenic-contaminated soil described in 4.3. Coumarin was immediately added as a ·OH scavenging agent, and the ·OH content in the water samples was determined by measuring the fluorescence intensity of 7-hydroxycoumarin using a microplate reader. Specific results are shown in [link to results]. Figure 5 .

[0047] Depend on Figure 5 It can be seen that a large amount of ·OH is continuously generated during the redox fluctuation of the redox cycle treatment system constructed by the "dry-wet alternation" cycle treatment, and the content of ·OH during the drying period is significantly higher than that during the flooding period.

[0048] 4.4.2 Humic acid in the remediated soil was characterized using an optical microscope. Specific results are shown in [link to results]. Figure 6 A. For example Figure 6 As shown in Figure A, after the repair was completed, obvious carbonization of the humic acid in the microbial agent could be observed under an optical microscope.

[0049] The carbonized region was further characterized using Raman spectroscopy. The results are shown below. Figure 6 B. For example Figure 6 As shown in B, graphite carbon is generated in the carbonized region, which is beneficial for the adsorption and fixation of arsenic in the soil.

[0050] 4.4.3 High-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was used to determine the arsenic speciation (As(III), As(V), DMA, and MMA) in the soil samples taken in 4.3. Specific results are shown in [link to results]. Figure 7 A.

[0051] Depend on Figure 7 As can be seen from A, after adding the microbial agent prepared in Example 1, the content of As(III) in the soil continued to decrease and was accompanied by a gradual increase in the content of As(V), DMA and MMA, indicating that the microbial agent prepared in Example 1 of the present invention effectively achieved the transformation of arsenic in the soil.

[0052] Further analysis of the proportion of different forms of arsenic in the soil during the four cycles of the remediation process is shown in the following figures. Figure 7 B. By Figure 7 As shown in B, after adding the microbial agent prepared in Example 1, the proportion of As(III) continued to decrease, accounting for only 3.8% after four reaction cycles. The proportions of As(V), DMA and MMA gradually increased, and most of the arsenic was effectively adsorbed and fixed. This indicates that the microbial agent of the present invention effectively reduced the toxicity of arsenic in the soil and achieved arsenic fixation, repaired arsenic-contaminated soil, and alleviated the toxicity and spread of arsenic in the soil.

[0053] The above descriptions are merely some embodiments of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A microbial inoculant, characterized in that, The microbial agent includes humic acid reducing bacteria and humic acid. The humic acid reducing bacteria is either Shewanella oneidensis MR-1 or Geobacter sulfurreducens, and the humic acid is either soil humic acid, water humic acid, or coal humic acid.

2. The microbial inoculant according to claim 1, characterized in that, The humic acid accounts for 50% to 70% of the mass of the microbial agent, and the content of humic acid-reducing bacteria in the microbial agent is 10. 6 ~10 9 cfu / g.

3. A method for preparing a microbial inoculant according to any one of claims 1 or 2, characterized in that, Includes the following steps: S1. Inoculate humic acid-reducing bacteria into anaerobic culture medium and anaerobically culture until OD. 600 =0.6~1.0, centrifuge to collect bacterial cells, and resuspend in sterile phosphate buffer to a bacterial concentration of 10. 8 ~10 9 A bacterial suspension of humic acid-reducing bacteria was prepared by using cfu / g. S2. Grind the humic acid, sieve it, rinse it with deionized water to remove soluble impurities, and dry it to obtain pretreated humic acid; S3. In an anaerobic glove box, the humic acid pretreated in step S2 is mixed with the bacterial suspension prepared in step S1 at a mass-to-volume ratio of 1:

20. After sealing, the mixture is shaken and cultured. After the culture is completed, the solid material is collected by centrifugation under anaerobic conditions, rinsed, and the unattached bacteria are removed to obtain a microbial agent. The agent is then stored in a wet state in an anaerobic bag at 4°C for later use.

4. The preparation method according to claim 3, characterized in that, In step S1, the humic acid-reducing bacteria are inoculated at a volume ratio of 1.5%, and the anaerobic fermentation medium comprises the following components: The ingredients are: 2.5 g / L sodium bicarbonate, 0.25~1.5 g / L ammonium chloride, 0.1~0.5 g / L yeast extract, and 20 mM sodium lactate. The anaerobic culture conditions are 30~60℃ and the anaerobic culture time is 36~96 hours. In step S2, the sieve mesh size is 150 mesh. The drying temperature is 60℃ and the drying time is 12 hours. In step S3, the shaking culture conditions are 25~60℃ and the shaking culture time is 24~48 hours.

5. The application of a microbial agent according to any one of claims 1 or 2, or a microbial agent prepared by any one of claims 3 or 4, in the remediation of arsenic pollution.

6. A method for remediating arsenic pollution in water bodies, characterized in that, The method is as follows: a microbial agent as described in any one of claims 1 or 2, or a microbial agent prepared by any one of claims 3 or 4, is mixed with arsenic-polluted water to construct an oxidation-reduction cycle treatment system, continuously oxidizing the trivalent arsenic contained in the arsenic-polluted water, and taking samples at the end of each cycle to determine the remediation status of the arsenic-polluted water.

7. The method according to claim 6, characterized in that, The microbial agent is mixed with the arsenic-contaminated water at a mass ratio of 1~5:995~999. The oxidation-reduction cycle treatment system creates an aerobic or anaerobic environment by continuously introducing air or high-purity N2 into the system.

8. The method according to claim 6, characterized in that, Each cycle of the redox cycle treatment system consists of an anaerobic period followed by an aerobic period, with the anaerobic period lasting 18-48 hours and the aerobic period lasting 6-24 hours. The reaction temperature of the redox cycle treatment system is 30-60℃, and the continuous reaction time of the redox cycle treatment system is 4-10 cycles.

9. A method for remediating arsenic pollution in soil, characterized in that, The method is as follows: a microbial agent according to any one of claims 1 or 2 or a microbial agent prepared by any one of claims 3 or 4 is mixed with arsenic-contaminated soil, and a dry-wet alternating treatment is carried out to construct an oxidation-reduction cycle treatment system to continuously oxidize the trivalent arsenic in the arsenic-contaminated soil. Samples are taken before the end of the aerobic period of each cycle to determine the remediation status of the arsenic-contaminated soil.

10. The method according to claim 9, characterized in that, The microbial agent is mixed with the arsenic-contaminated soil at a mass ratio of 1-5:995-999. The oxidation-reduction cycle treatment system creates anaerobic and aerobic environments by alternating drying and flooding of the arsenic-contaminated soil. In each cycle of the oxidation-reduction cycle treatment system, the drying period is 1-3 days and the flooding period is 2-6 days. The continuous reaction time of the oxidation-reduction cycle treatment system is 8-20 cycles.

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