Metolachlor anaerobic degradation strain SRB-9 and application thereof

Abstract

The invention belongs to the technical field of environmental microorganisms, and particularly relates to a metolachlor anaerobic degradation strain SRB-9 and application thereof. According to the present invention, a strain SRB-9 capable of efficiently and anaerobically degrading metolachlor (MET) is separated from anaerobic sediments, and the morphological and molecular biological identification results show that the strain belongs to nitrate desulfurization vibrio, is named as Nitatidesulfurvibrio sp. SRB-9, is preserved in the China Center for Type Culture Collection (CCTCC), and has a preservation number of CCTCC M 20251781. The invention further provides a preparation method of the metolachlor-metolachlor anaerobic degradation strain SRB-9, and the metolachlor-metolachlor anaerobic degradation strain SRB-9 can be used for efficiently and anaerobically degrading metolachlor-metolachlor anaerobic degradation strain SRB-9, the bacterial strain can rapidly degrade MET under anaerobic conditions, and the degradation half-life period of the bacterial strain to MET with the concentration of 100 [mu] M is 9.6 d. And the strain can also be used for rapidly and anaerobically degrading five kinds of chloroacetamide herbicides such as alachlor, acetochlor, propisochlor, pretilachlor and butachlor. The strain disclosed by the invention is beneficial to repairing wastewater or soil polluted by various chloroacetamide herbicides, enriches a resource library of pesticide degrading bacteria, and has a good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of environmental microbiology technology, and in particular, this invention relates to an anaerobic degrading strain of isopropyl methylamine, SRB-9, and its applications. Background Technology

[0002] Metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide, MET] is a selective pre-emergence herbicide belonging to the chloroacetamide class. Its main mechanism of action involves inhibiting plant respiration, interfering with protein biosynthesis, and affecting the integrity of biofilms. This product is primarily used for weed control in fields of corn, soybeans, cotton, peanuts, and rice. As one of the world's most important herbicides, its sales have consistently ranked among the top herbicides, and it remains a core product in the global pesticide market.

[0003] Due to its stable chemical properties, high water solubility, and large-scale use, MET poses a potential risk to aquatic environments and has been frequently detected in rivers, lakes, and even groundwater in several countries, including the United States and China. Toxicological studies have shown that MET is also highly toxic to aquatic organisms such as fish, water fleas, and algae. Furthermore, MET has been found to strongly inhibit the quantity and activity of soil microorganisms, significantly reducing soil microbial abundance and diversity, and may have potential impacts on human health. Therefore, in the context of developing sustainable agriculture, research on the environmental fate of MET, risk assessment, and pollution remediation technologies is receiving increasing attention.

[0004] MET in the environment is primarily degraded through microbial activity. Compared to traditional physicochemical remediation methods, microbial degradation technology offers advantages such as high efficiency, speed, and no secondary pollution, while also being cost-effective, at only about 10% of traditional physical and chemical methods. Therefore, it has become a major remediation strategy for environmental pollution. Based on the differences in oxygen requirements of microorganisms, microbial degradation can be divided into aerobic and anaerobic types. Among them, anaerobic bioremediation has become an important method for environmental pollution remediation due to its low energy consumption, high sludge loading, low nutrient requirements, good economic benefits, and wide applicability.

[0005] Currently, there are aerobic degrading strains for MET isolation and screening. Streptomyces sp、 Paracoccus strains such as sp. FLY-8 have low degradation efficiency for MET. Paracoccussp. FLY-8 showed a degradation rate of only 22% for 100 mg / LMET within 5 days. Because MET easily enters anaerobic or microaerobic environments such as sediments, wetlands, flooded soils, and groundwater during use, and currently reported anaerobic degrading strains of MET are scarce, with only a few strains... Proteiniclasticum sediminis BAD-10 T and Cupidesulfovibrio sp. SRB-5, etc. Therefore, the discovery and application research of MET anaerobic degrading bacterial strains is of great significance for enriching MET degrading bacterial strain resources and MET bioremediation applications. Summary of the Invention

[0006] To address the aforementioned shortcomings of existing technologies, this invention provides a strain SRB-9 and its application in the anaerobic degradation of the herbicide metolachlor (MET). This invention isolates and identifies an anaerobic strain that degrades metolachlor (MET), studies its degradation characteristics, substrate profile, and bioremediation potential, and the results enrich the herbicide-degrading bacterial resource library, providing technical support for the development of new herbicide residue remediation methods.

[0007] In a first aspect, the present invention provides a MET anaerobic degrading strain SRB-9, belonging to the genus *Vibrio nitrate-desulfurizing* (…). Nitratidesulfovibrio Its classification is named Nitratidesulfovibrio sp. SRB-9 was deposited on August 5, 2025 at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC M 20251781. The deposit address is: Wuhan University, No. 299 Bayi Road, Wuchang District, Wuhan, Hubei Province.

[0008] The anaerobic degrading strain SRB-9 of the present invention forms round colonies on MPM solid plates with a diameter of 0.1-0.3 mm, a smooth surface, and a pale yellow color; the bacterial cells are curved and arc-shaped, have flagella, and are 0.4-0.6 μm × 2-2.6 μm in size.

[0009] In a second aspect, the present invention provides a microbial agent for degrading the herbicide MET, said microbial agent containing Nitratidesulfovibrio sp. SRB-9.

[0010] In some embodiments, the microbial agent is a liquid microbial agent, a solid microbial agent, or a powder.

[0011] In some embodiments, the liquid bacterial agent comprises: an emulsion, a suspension, or a fermentation broth containing strain SRB-9; in one embodiment, the liquid bacterial agent is prepared by resuspending the bacterial cells in a buffer solution, wherein the bacterial agent contains... Nitratidesulfovibrio The number of sp. SRB-9 is 1.0 × 10 6 -1.0 × 109 cfu / mL.

[0012] In some embodiments, the bacterial agent is a solid bacterial agent, prepared by immobilizing the bacterial cells onto a solid carrier.

[0013] In some embodiments, the powder includes lyophilized powder and wettable powder.

[0014] In a third aspect, the present invention provides the application of the anaerobic degrading strain SRB-9 of the present invention to degrade six chloroacetamide herbicides, namely MET, metolachlor, acetochlor, isopropachlor, pretilachlor, and butachlor, in the environment or equipment facilities. Preferably, the environment is livestock manure compost, livestock wastewater, groundwater, flooded soil, and wetlands contaminated with MET, metolachlor, acetochlor, isopropachlor, pretilachlor, or butachlor. Preferably, the equipment facilities are wastewater treatment equipment or facilities.

[0015] This invention utilizes anaerobic sludge collected from near a farm. After enrichment, domestication, and purification, a strain capable of efficiently and rapidly degrading MET through anaerobic processes was obtained. Morphological and molecular biological identification confirmed that this strain belongs to the genus *Vibrio nitrate-desulfurizing*. Nitratidesulfovibrio ), named Nitratidesulfovibrio sp. SRB-9. This strain can rapidly degrade MET under anaerobic conditions, with a degradation half-life of 9.6 days for 100 μM MET, indicating that the anaerobic degrading strain SRB-9 can be used as a biodegrading bacterium for the bioremediation of MET-contaminated environments.

[0016] Beneficial effects: (1) This invention screened and obtained a highly efficient MET anaerobic degradative strain, namely Nitratidesulfovibrio sp. SRB-9, the resulting strain SRB-9, has a good anaerobic degradation effect on MET and enriches the seed resource bank for anaerobic degradation of herbicides.

[0017] (2) The strain SRB-9 of the present invention has a high efficiency in anaerobic degradation of MET. The degradation half-life of MET at a concentration of 100 μM is 9.6 d, indicating that strain SRB-9 has good remediation potential in the bioremediation of anaerobic environments contaminated with MET.

[0018] (3) The strain SRB-9 of the present invention can not only rapidly degrade MET, but also rapidly degrade five other chloroacetamide herbicides such as metolachlor, acetochlor, isopropachlor, propachlor and butachlor.

[0019] (4) The strains of the present invention can be widely used for anaerobic remediation of chloroacetamide-based weed-contaminated environments such as anaerobic sewage treatment plants, anaerobic reactors, groundwater and flooded soil. Attached Figure Description

[0020] Figure 1 Colony and cell morphology of anaerobic strain SRB-9, where A represents the colony morphology of anaerobic strain SRB-9 and B represents the cell morphology.

[0021] Figure 2 Phylogenetic analysis of the 16S rRNA gene of anaerobic strain SRB-9.

[0022] Figure 3 The effects of environmental conditions on the degradation of isometolachlor by the anaerobic strain SRB-9 were investigated. Specifically, A represents the effect of different temperatures on the degradation of isometolachlor by the anaerobic strain SRB-9; B represents the effect of different pH values ​​on the degradation of isometolachlor by the anaerobic strain SRB-9; C represents the effect of different electron acceptors on the degradation of isometolachlor by the anaerobic strain SRB-9; and D represents the effect of different electron donors on the degradation of isometolachlor by the anaerobic strain SRB-9.

[0023] In this invention, the MET anaerobic degrading strain SRB-9 belongs to the genus *Vibrio nitrate-desulfurizing* (…). Nitratidesulfovibrio Its classification is named Nitratidesulfovibrio sp. SRB-9 was deposited on August 5, 2025 at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC M 20251781. The deposit address is: Wuhan University, No. 299 Bayi Road, Wuchang District, Wuhan, Hubei Province.

[0024] In this invention, "strain SRB-9", "anaerobic degrading strain SRB-9", and " Nitratidesulfovibrio "sp.SRB-9" refers to the strain with accession number CCTCC M 20251781 screened in this invention. Those skilled in the art will understand that they have the same meaning in this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Unless otherwise specified, the equipment and reagents used in the embodiments and experimental examples are commercially available. Unless otherwise stated, all reagents used in this invention are analytical grade reagents. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0026] The culture medium formulations described in the following examples are as follows: Anaerobic enrichment and acclimatization medium (MSM, g / L): K2HPO4·3H2O, 0.35 g; KH2PO4, 0.27 g; MgCl2·6H2O, 0.15 g; NH4Cl, 0.53 g; CaCl2·2H2O, 0.073 g; sodium pyruvate, 0.5 g; FeSO4·7H2O, 0.5 g (added before boiling and dispensing); ascorbic acid, 0.1 g (added before boiling and dispensing); resazurite, 1.0 mg; trace element complex solution, 1.0 mL; vitamin complex solution, 1.0 mL (added after sterilization); pH 7.0, diluted with pure water to 1.0 L.

[0027] Anaerobic isolation and culture medium (MPM, g / L): NH4Cl, 1.0 g; NaCl, 1.0 g; K2HPO4·3H2O, 0.5 g; MgCl2·6H2O, 0.05 g; Na2SO4, 1.1 g; CaCl2·2H2O, 0.05 g; sodium lactate, 2.0 g; ascorbic acid, 0.10 g; cysteine ​​hydrochloride, 0.2 g; yeast extract, 1.0 g; resazurite, 1.0 mg; trace element complex solution, 1.0 mL; vitamin complex solution, 1.0 mL; pH adjusted to 7.2 with phosphate buffer, and purified water added to 1.0 L. Solid medium supplemented with 1.7% agar.

[0028] Deoxygenation of the culture medium: Boil the prepared culture medium, and while it is still hot, dispense 30 mL of the medium into 50 mL serum bottles. Seal the bottles with rubber stoppers and secure them with aluminum caps. Purge with nitrogen for 30 minutes to remove oxygen, then autoclave at 115 °C for 30 minutes. The sterilized culture medium should remain colorless. If the color turns slightly red or red, it indicates that oxygen has not been completely removed.

[0029] Detection conditions for chloroacetamide herbicides: High performance liquid chromatography (1260 Infinity II, Agilent, USA); Agilent XDB-C 18 (5 μm, 4.6 × 250 mm); Mobile phase: acetonitrile: ultrapure water = 80:20 (v / v); Detection wavelength: 222 nm; Flow rate: 1.0 mL / min; Column temperature: 30 °C; Injection volume: 20 μL.

[0030] Example 1 Isolation and Identification of Strain SRB-9 (1) Enrichment, domestication and isolation of MET anaerobic degrading bacteria

[0031] Sludge from the sediment was inoculated into serum bottles containing 100 μM MET and 30 mL MSM, and incubated at 37 °C and 150 rpm for 7 days. The previous generation enrichment solution was transferred at a concentration of 5% to 30 mL of fresh MSM containing 100 μmol / L MET. The MET degradation rate in each transfer was measured to be above 90%, and this process was repeated up to four generations. The fifth generation enrichment solution was then spread onto MPM solid medium containing 100 mg / L MET using the dilution-spreading method in an anaerobic chamber. The plates were inverted and placed in an anaerobic jar, and incubated at 37 °C for 7 days. After single colonies grew on the plates, they were streaked multiple times for purification, and their MET degradation effect was verified.

[0032] Using MET as the selection pressure, a MET-degrading anaerobic bacterium, designated SRB-9, was finally isolated and purified.

[0033] (2) Morphological and molecular biological identification of anaerobic degrading strain SRB-9 In an anaerobic chamber, the anaerobic degrading strain SRB-9 was inoculated onto MPM solid plates and incubated at 37 °C for 7 days. Colony morphology was then observed. The colonies of the anaerobic degrading strain SRB-9 on MPM solid plates were round, 0.1–0.3 mm in diameter, with a smooth surface and a pale yellow color. Figure 1 (A) The bacterial cells are curved and arc-shaped, with flagella, and measure 0.4–0.6 μm × 2–2.6 μm. Figure 1 (B). This strain is Gram-negative and grows strictly anaerobicly; it can grow at temperatures ranging from 16 to 47 °C, with an optimal growth temperature of 37–42 °C; it can also grow at pH values ​​ranging from 5.0 to 10.0, with an optimal growth pH of 6.0–9.0.

[0034] Total DNA was extracted from strain SRB-9 using a high-salt method. The 16S rRNA gene sequence of strain SRB-9 was amplified using the universal primer pairs 27F (5′-AGAGTTTGATCCTGGCTCAG-3′) and 1492R (5′-TACGGCTACCTTGTTACGACTT-3′) as templates for bacterial identification. The PCR amplification product was sequenced by a sequencing company. The obtained 16S rRNA gene sequence of strain SRB-9 was compared with the 16S rRNA genes of reported type strains in the EzBioCloud database (www.ezbiocloud.net) for homology analysis. Sequences with high homology to type strains were selected, and a phylogenetic tree of resistant strains was constructed using the neighbor-joining method with MEGA 11.0 software. Figure 2As shown, the 16S rRNA gene sequence of the strain SRB-9 isolated in this invention is similar to... Nitratidesulfovibrio vulgaris Hildenborough T The highest homology was 98.45%.

[0035] Therefore, based on the morphological and molecular biological identification results of strain SRB-9, the anaerobic degrading strain SRB-9 was identified as belonging to the genus *Vibrio nitrate-desulfurizing*. Nitratidesulfovibrio ), named Nitratidesulfovibrio sp.SRB-9. The strain SRB-9 isolated in this invention belongs to the genus *Vibrio nitratedesulfonii*. Nitratidesulfovibrio This discovery enriches the seed resource bank of MET-degrading bacteria. The strain was deposited on August 7, 2025, at the China Center for Type Culture Collection (CCTCC M 20251781), located at Wuhan University, No. 299 Bayi Road, Wuchang District, Wuhan, Hubei Province. Example 2 Study on the MET degradation characteristics of anaerobic strain SRB-9

[0036] Add 1.0 mL of bacterial culture (OD) of strain SRB-9 to the deoxygenated MSM. 600 = 0.6) and a certain amount of MET were added to make a final concentration of 100 μM, and then the mixture was incubated in a shaker at 37 °C and 150 rpm. The concentration of MET was measured at different time points. The control group did not contain strain SRB-9. Each control and treatment group was repeated three times. Following the above procedure, the effects of different temperatures (16 °C, 25 °C, 30 °C, 37 °C, 42 °C and 47 °C), different pH values ​​(5.0, 6.0, 7.0, 8.0, 9.0 and 10.0), different electron acceptors (Na2SO4, NaNO3, FeCl3 and Na2CO3) and different electron donors (sodium formate, sodium acetate, sodium pyruvate, sodium succinate, sodium lactate and sodium citrate) on the degradation of MET by the anaerobic degrading strain SRB-9 were studied.

[0037] Depend on Figure 3 It can be seen that the anaerobic degrading strain SRB-9 achieves a MET degradation rate of over 50% at temperatures of 30-47 °C and over 70% at temperatures of 37-42 °C. Its optimal temperature for MET degradation is 37-42 °C. Figure 3 (A). At pH 6.0-10.0, the anaerobic degrading strain SRB-9 exhibits a MET degradation rate greater than 50%, with the optimal pH for MET degradation being 6.0-10.0. Figure 3 (B) The effects of different electron acceptors on the degradation of MET by the anaerobic degrading strain SRB-9, as shown in Figure 1. Figure 3As shown in Figure C, strain SRB-9 could not degrade MET without the addition of an electron acceptor or with the addition of NaNO3, FeCl3, or Na2CO3 as electron acceptors. Only with the addition of Na2SO4 as an electron acceptor could strain SRB-9 degrade MET, indicating that sulfate is the optimal electron acceptor for the anaerobic degradation of MET by strain SRB-9. The effects of different electron donors on the MET degradation by strain SRB-9 are shown below. Figure 3 As shown in Figure D, compared with MSM without electron acceptors, strain SRB-9 was able to rapidly degrade MET when sodium formate, sodium succinate, and sodium lactate were added, indicating that the optimal electron acceptors for the anaerobic degradation of MET by strain SRB-9 are sodium formate, sodium succinate, and sodium lactate.

[0038] The above results indicate that the optimal temperature range for the anaerobic degrading strain SRB-9 to degrade MET is 37-42 °C, the optimal pH range is 6.0-10.0, the optimal electron acceptor is sulfate, and the optimal electron donors are sodium formate, sodium succinate, and sodium lactate. Example 3: Determination of the anaerobic degradation ability of anaerobic strain SRB-9 on MET

[0039] 1.0 mL of anaerobic strain SRB-9 bacterial culture (OD) 600 = 0.6) was added to 30 mL of deoxygenated MSM at pH 7.0, followed by the addition of a certain amount of MET to achieve final concentrations of 10 μM, 100 μM, 400 μM, and 800 μM. The mixture was then incubated at 37 °C and 150 rpm in a shaker. Samples were taken at different time points to determine the concentration of metolachlor, and the anaerobic degradation dynamics of metolachlor were fitted to calculate its half-life. The control group did not receive the anaerobic degrading strain SRB-9. Each control and treatment group had three replicates.

[0040] The experimental results of the degradation of metolachlor by anaerobic strain SRB-9 at different concentrations are shown in Table 1. The degradation dynamics of metolachlor by strain SRB-9 conformed to the first-order kinetic equation. With time as the horizontal axis and the residual concentration of MET as the vertical axis, the first-order kinetic equation was used ( C = C 0e -kt The fitting equation is derived from the correlation coefficient R. 2 (0.9589-0.9858) indicates that the degradation dynamics of metolachlor by the anaerobic degrading strain SRB-9 follow first-order kinetics. The degradation half-lives of the anaerobic degrading strain SRB-9 for MET at concentrations of 10 μM, 100 μM, 400 μM, and 800 μM (…) are shown in the table. T 1 / 2The degradation times (ln2 / k) were 17.64 d, 9.61 d, 11.12 d, and 21.82 d, respectively. This indicates that the anaerobic degrading strain SRB-9 obtained by screening in this invention has a high degradation efficiency for metolachlor and has great potential for application in the remediation of metolachlor pollution.

[0041] Table 1. First-order kinetic parameters fitted by strain SRB-9 for anaerobic degradation of MET at different concentrations

[0042] Example 4: Study on the effect of anaerobic strain SRB-9 on the anaerobic degradation of different MET isomers

[0043] 1.0 mL of anaerobic degrading strain SRB-9 bacterial culture (OD) 600 = 0.6) was added to 30 mL of deoxygenated MSM at pH 7.0, and then a certain amount of α was added. R ,1 S -Met, α R , 1 R -Met, α S , 1 R -Met and α S , 1 S MET was added to a final concentration of 100 μM, and then cultured in a shaker at 37 °C and 150 rpm. Samples were taken at different time points to determine the concentrations of different MET isomers, and their anaerobic degradation dynamics were fitted to calculate their half-life. The control group did not contain the anaerobic degrading strain SRB-9. Both the control and treatment groups were triple-replicated.

[0044] The experimental results of the degradation of different MET isomers by the anaerobic degrading strain SRB-9 are shown in Table 2. The degradation dynamics of different MET isomers by strain SRB-9 conform to the law of first-order kinetic equation. Plotting time on the horizontal axis and the residual concentration of different MET isomers on the vertical axis, the first-order kinetic equation (C = C0e^(-1 / 2)) is used. -kt The fitting equation is derived from the correlation coefficient R. 2 (0.8443-0.9359) indicates that the degradation dynamics of different MET isomers by the anaerobic degrading strain SRB-9 follow first-order kinetics. The anaerobic degrading strain SRB-9 also exhibits degradation dynamics of α-MET isomers. R ,1 S -MET, α R , 1 R -MET, α S , 1 R -MET, α S , 1 S -MET degradation half-life (T 1 / 2The degradation times (ln2 / k) were 11.83 d, 13.03 d, 12.23 d, and 11.34 d, respectively. This indicates that the anaerobic degrading strain SRB-9 obtained by screening in this invention has a high degradation efficiency for all four MET isomers without selectivity, and has great potential for MET pollution remediation.

[0045] Table 2. First-order kinetic parameters fitted by strain SRB-9 for anaerobic degradation of different MET isomers

[0046] Example 5: Study on the anaerobic degradation ability of anaerobic strain SRB-9 against six chloroacetamide herbicides

[0047] 1.0 mL of anaerobic degrading strain SRB-9 bacterial culture (OD) 600 = 0.6) was added to 30 mL of deoxygenated MSM at pH 7.0, followed by the addition of specific amounts of metolachlor, acetochlor, propachlor, butachlor, isopropachlor, and isopropachlor to achieve a final concentration of 100 μM. The mixture was then incubated at 37 °C and 150 rpm in a shaker. Samples were taken at different time points to determine the concentrations of the six chloroacetamide herbicides, and their anaerobic degradation dynamics were fitted to calculate their half-lives. The control group did not receive the anaerobic degrading strain SRB-9. Each control and treatment group was tested in triplicate.

[0048] The experimental results of the degradation of six chloroacetamide herbicides by the anaerobic degrading strain SRB-9 are shown in Table 3. The degradation dynamics of the six chloroacetamide herbicides by strain SRB-9 conformed to the law of first-order kinetic equation. With time as the horizontal axis and the residual concentration of the six chloroacetamide herbicides as the vertical axis, the first-order kinetic equation (C = C0e) was used. -kt The fitting equation is derived from the correlation coefficient R. 2 (0.8804-0.9886) indicates that the degradation dynamics of the six chloroacetamide herbicides by the anaerobic degrading strain SRB-9 follow first-order kinetics. The degradation half-lives (T1) of anaerobic degrading strain SRB-9 for metolachlor, acetochlor, propachlor, butachlor, isopropachlor, and isopropachlor are shown in the table. 1 / 2 The degradation times (ln2 / k) were 3.14 d, 3.11 d, 2.93 d, 5.93 d, 4.17 d, and 9.14 d, respectively. The degradation rates were: metolachlor ≈ acetochlor ≈ propachlor > propachlor > butachlor > propachlor. This indicates that the anaerobic degrading strain SRB-9 obtained by this invention has high degradation efficiency for all six chloroacetamide herbicides and can be well applied to sites contaminated by chloroacetamide herbicides. Table 3. First-order kinetic parameters of anaerobic degradation of six chloroacetamide herbicides by strain SRB-9

[0049] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection defined by the claims submitted herein.

Claims

1. An anaerobic degrading strain of metolachlor, SRB-9, characterized in that, The strain was classified and named Nitratidesulfovibrio sp. SRB-9 was deposited on August 5, 2025 at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC M 20251781. The deposit address is: Wuhan University, No. 299 Bayi Road, Wuchang District, Wuhan, Hubei Province.

2. The isopropylmetribalaine-degrading anaerobic strain SRB-9 according to claim 1, characterized in that, The anaerobic degrading strain SRB-9 forms round colonies on MPM solid plates. The colonies are smooth, pale yellow, and 0.1–0.3 mm in diameter. The bacterial cells are curved and arc-shaped with polar flagella, and 0.4–0.6 μm × 2.0–2.6 μm in size.

3. A microbial agent for degrading the herbicide metolachlor, characterized in that, The bacterial agent contains the strain described in claim 1. Nitratidesulfovibrio sp. SRB-9.

4. The microbial agent according to claim 3, characterized in that, The microbial agent can be a liquid microbial agent, a solid microbial agent, or a powder.

5. The microbial agent according to claim 4, characterized in that, The bacterial agent is a liquid bacterial agent; preferably, the liquid bacterial agent is an emulsion, a suspension, or a bacterial fermentation broth containing strain SRB-9.

6. The microbial agent according to claim 5, characterized in that, The bacterial agent Nitratidesulfovibrio The quantity of sp.SRB-9 is 1.0 × 10 6 -1.0 × 10 9 cfu / mL.

7. The microbial agent according to claim 3, characterized in that, The powder is a lyophilized powder or a wettable powder.

8. The application of the microbial agent according to any one of claims 3-7, characterized in that, The microbial agent is used to degrade isopropylate and other chloroacetamide herbicides in the environment or equipment facilities; preferably, the chloroacetamide herbicides are metolachlor, acetochlor, isopropylate, propachlor, and butachlor.

9. The application of the isopropylmetribalaine anaerobic degrading strain SRB-9 according to claim 1, characterized in that, The anaerobic degrading strain SRB-9 is used to degrade metolachlor and other chloroacetamide herbicides in the environment or equipment facilities; preferably, the chloroacetamide herbicides are metolachlor, acetochlor, metolachlor, propachlor, and butachlor.

10. The application according to claim 9, characterized in that, The environment refers to livestock and poultry manure compost, aquaculture wastewater, groundwater, flooded soil, and wetlands contaminated with isopropyl acetylamine and five other chloroacetamide herbicides; the equipment and facilities refer to wastewater treatment equipment and facilities.

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