Aquatic microbacterium and its application in degrading atrazine

Abstract

This invention discloses an aquatic microbacterium and its application in the degradation of atrazine. The aquatic microbacterium is named *Aquamicrobium lusatiense* HR8, with accession number CGMCC No. 28916. This invention also discloses a microbial agent comprising the aquatic microbacterium, a method for culturing the aquatic microbacterium, and a method for degrading triazine herbicides. This invention is the first to disclose the use of *Aquamicrobium* to degrade atrazine. Aquamicrobium HR8 achieved a 100% degradation rate of 200 mg / L atrazine in 48 hours. Its application in the bioremediation of atrazine-contaminated environments can overcome the current shortcomings of poor atrazine bioremediation and removal efficiency, while simultaneously reducing secondary pollution to the environment.

Description

Technical Field

[0001] This invention relates to the field of biodegradation, specifically to an aquatic microbacterium and its application in the degradation of atrazine. Background Technology

[0002] Atrazine (2-chloro-4-diethylamino-6-isopropylamino-1,3,5-triazine) is a water-soluble triazine herbicide with a broad spectrum of weed control, effective against a variety of annual grasses and broadleaf weeds, and also exhibiting some inhibitory effects on certain perennial weeds. It effectively controls barnyard grass, foxtail, sedge, amaranth, knotweed, lambsquarters, cruciferous and legume weeds, and is suitable for dryland crops such as corn, sorghum, sugarcane, fruit trees, nurseries, and woodlands. It was initially patented in 1958 and began commercial use in the United States in 1959. Currently, it is one of the most widely used herbicides in the world, with an annual production exceeding 36,000 tons.

[0003] The widespread use of atrazine has led to a series of environmental and ecological problems. Its persistent and mobile nature in aquatic environments results in high residue levels in soil and groundwater, and once it enters a watershed, it can spread for miles. In addition to direct consequences such as reduced biodiversity, yield losses, and food safety issues, it also has long-term reproductive, endocrine, and hormonal disruption effects. It harms not only crustaceans, insects, mollusks, fish, amphibians, and reptiles, but can also cause birth defects, low birth weight, reproductive tumors, low sperm count in men, and menstrual problems in women.

[0004] Therefore, removing atrazine from the environment is considered an urgent priority, and exploring effective remediation measures to eliminate atrazine in the environment has become a research hotspot. Currently, from the perspectives of cost, efficiency, quality, degradation efficiency, and safety, microbial-enhanced bioremediation remains the most promising method for pesticide degradation. Researchers have isolated and screened a large number of atrazine-degrading bacteria from various environments, including bacteria, fungi, and actinomycetes, but existing degrading strains still have significant limitations. Therefore, screening for highly efficient atrazine-degrading strains, processing them into microbial agents through fermentation, and applying them to the degradation of pesticide residues to eliminate atrazine residues in soil, water bodies, and agricultural products remains the primary task of remediation work. Summary of the Invention

[0005] To address the lack of a highly efficient bacterium or fungicide for degrading triazine herbicides such as atrazine in existing technologies, this invention provides an aquamicrobacterium and its application in atrazine degradation. The Aquamicrobium lusatiense HR8 provided by this invention has the advantage of highly efficient degradation of triazine herbicides.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] One of the technical solutions provided by this invention is: an isolated bacterium, the bacterium being Aquamicrobium lusatiense, named Aquamicrobium lusatiense HR8, which is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC No. 28916, and the deposit date being November 8, 2023.

[0008] The biological characteristics of the bacteria are as follows: colonies are regular in shape, round, with smooth edges, pale yellow to yellow, opaque, moist and viscous, and easily picked up; mature colonies have a diameter of 0.5 cm. In R2A liquid fermentation medium, it reaches the logarithmic growth phase within 48 hours of shaking culture and reaches the stationary phase within 5 days. The fermentation broth is turbid, milky yellow, and viscous. This bacterium is a Gram-negative aerobic bacterium that can use atrazine as its sole carbon source; it grows in an environment with a temperature of 20–40℃ and a pH of 5.0–9.0.

[0009] The bacteria were sequenced by 16S rDNA and compared with sequences in GenBank by BLAST homology. The results showed that the strain had high homology with Aquamicrobium lusatiense, with a similarity of more than 99%. The strain was named Aquamicrobium lusatiense HR8.

[0010] The second technical solution provided by the present invention is: a bacterial agent, wherein the bacterial agent includes the bacteria as described in the first technical solution.

[0011] In a specific embodiment of the present invention, the viable count of the bacteria in the bacterial agent is 1×10⁻⁶. 4 CFU / mL or higher, 1×10 5 CFU / mL or higher, 1×10 6 CFU / mL or higher, 1×10 7 CFU / mL or higher or 1×10 8 CFU / mL or higher, for example, 1×10 4 ~1×10 8 CFU / mL.

[0012] In a specific embodiment of the present invention, the microbial agent further includes a culture medium for culturing the bacteria and / or microbial agent excipients.

[0013] In a specific embodiment of the present invention, the culture medium is LB medium or R2A medium; and / or, the excipients for the microbial agent include excipients, disintegrants, binders, thickeners, solubilizers, preservatives, lubricants and / or lyophilization protectants.

[0014] In this invention, the bacterial agent uses an effective amount of the bacteria as the active ingredient and can be prepared by adding conventional excipients, disintegrants, binders, thickeners, solubilizers, preservatives, lubricants and / or lyophilization protectants, etc., according to conventional formulation processes in the art.

[0015] The third technical solution provided by the present invention is: a method for culturing bacteria as described in one of the technical solutions, the method comprising culturing the bacteria in a culture medium.

[0016] In this invention, the culture medium can be a conventional culture medium in the art, the culture temperature can be a conventional temperature in the art, the culture time can be a conventional time in the art, the culture pH can be a conventional pH in the art, and the culture rotation speed can be a conventional rotation speed in the art. The initial inoculum size can be a conventional inoculum size in the art, as long as these culture conditions are sufficient to grow Aquamicrobium lusatiense HR8. After culture, the effective viable count in the culture medium can reach 10. 4 More than 1 / mL.

[0017] In a specific embodiment of the present invention, the method satisfies one or more of the following conditions:

[0018] (1) The culture medium is LB medium or R2A medium;

[0019] (2) The culture temperature is 20-40℃, preferably 30℃;

[0020] (3) The culture time is 24 to 60 hours, preferably 48 hours;

[0021] (4) The pH of the culture is 5.0 to 9.0, preferably 7.0;

[0022] (5) The culture rotation speed is 150–180 rpm, preferably 160 rpm; and,

[0023] (6) The initial inoculum amount for the culture is 2% (v / v) to 20% (v / v), preferably 15% (v / v).

[0024] The fourth technical solution provided by the present invention is: a method for preparing the bacterial agent as described in the second technical solution, the method comprising culturing the bacteria using the method described in the third technical solution.

[0025] The fifth technical solution provided by the present invention is: a method for degrading triazine herbicides, the method comprising: applying bacteria as described in technical solution one or a microbial agent as described in technical solution two to an area contaminated by the triazine herbicide.

[0026] Triazine herbicides, also known as triazine-based herbicides, are widely used for pre- and post-emergence weed control, managing the growth of annual herbaceous plants and broadleaf weeds. There are 36 varieties of triazine herbicides, divided into symmetrical triazines (1,3,5-triazines, also known as homotriazines) and asymmetrical triazines (1,2,4-triazines). Homotriazines are the main commercial herbicides and can be further divided into chlorinated triazines (such as atrazine, simazine, and terbufos), thiomethyl-S-triazines (such as promethazine, atrazine, and terbufos), fluoroalkyl-S-triazines (such as triazine-indoxachlor and triazine-fluazine), and methoxytriazines (such as propiconazole and terbufos). These herbicides are selective herbicides, targeting the D1 protein of photosynthetic system II (PSII) and exerting their weed-controlling effect by inhibiting plant photosynthesis.

[0027] In a specific embodiment of the present invention, the triazine herbicide includes triazine herbicides.

[0028] In a specific embodiment of the present invention, the triazine herbicide includes atrazine.

[0029] In a specific embodiment of the present invention, the viable count of the bacteria or the bacterial agent is 1 × 10⁻⁶. 4 CFU / g or higher, 1×10 5 CFU / g or higher, 1×10 6 CFU / g or higher, 1×10 7 CFU / g or higher or 1×10 8 CFU / g or higher, for example, 1×10 4 ~1×10 8 CFU / g.

[0030] In a specific embodiment of the present invention, the conditions for the degradation of the triazine herbicide by the bacteria or the bacterial agent satisfying one or more of the following:

[0031] (1) The temperature is 20-40℃, preferably 30℃;

[0032] (2) The duration is 2 days or more, 3 days or more, 5 days or more, 7 days or more, 10 days or more, 14 days or more, 20 days or more, or 28 days or more; and,

[0033] (3) The pH is 5.0 to 9.0, preferably 7.0.

[0034] In this invention, the conditions for degrading the triazine herbicide can be conventional in the art, suitable for the growth and metabolism of the strain, such as temperature, time and / or pH, as long as these conditions can degrade the triazine herbicide.

[0035] The sixth technical solution provided by the present invention is: the application of bacteria as described in technical solution one or bacterial agents as described in technical solution two in the degradation of triazine herbicides.

[0036] In a specific embodiment of the present invention, the triazine herbicide includes triazine herbicides.

[0037] In a specific embodiment of the present invention, the triazine herbicide includes atrazine.

[0038] The reagents and raw materials used in this invention are all commercially available.

[0039] The positive and progressive effects of this invention are as follows:

[0040] This invention discloses for the first time the degradation of atrazine using aquamicrobium. The aquamicrobium HR8 of this invention achieves a 100% degradation rate of 200 mg / L atrazine in 48 hours. Applied to the bioremediation of atrazine-contaminated environments, it overcomes the shortcomings of current bioremediation methods for atrazine removal, while simultaneously reducing secondary pollution. Furthermore, this invention provides a microbial agent containing aquamicrobium HR8 for atrazine degradation. This agent is easy to use, has low operating costs, good efficacy, and minimal negative environmental impact, showing great promise for development and utilization. The aquamicrobium HR8 of this invention is of great significance for reducing and eliminating atrazine contamination in groundwater and soil.

[0041] Information on the preservation of biological materials

[0042] The aquatic microorganism Aquamicrobium lusatiense HR8 of this invention was deposited on November 8, 2023, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, 100101, China, with accession number CGMCC No. 28916. The culture name is Aquamicrobium lusatiense HR8, and the classification name is Aquamicrobium lusatiense. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0044] Figure 1 The colony morphology of strain HR8 on R2A solid medium.

[0045] Figure 2 Images of strain HR8 under a thermal field emission scanning electron microscope.

[0046] Figure 3 This is an image of colonies formed by atrazine lysis zones after strain HR8 was cultured for 5 days in MSM basal inorganic salt medium containing 500 mg / L atrazine.

[0047] Figure 4 The comparison results of strain HR8 on NCBI are shown.

[0048] Figure 5 Phylogenetic tree of strain HR8.

[0049] Figure 6 Standard curve for atrazine.

[0050] Figure 7 The degradation curve of atrazine by strain HR8 is shown.

[0051] Figure 8 The degradation of atrazine by HR8 under different atrazine concentrations is shown in the figure.

[0052] Figure 9 The degradation of atrazine by HR8 under different inoculation amounts is shown in the diagram.

[0053] Figure 10 The degradation of atrazine by HR8 under different temperature conditions is shown in the diagram.

[0054] Figure 11 The degradation of atrazine by HR8 under different pH conditions is shown in the diagram. Detailed Implementation

[0055] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0056] The culture medium used in the examples includes:

[0057] LB medium: 10g peptone, 5g yeast extract, 10g NaCl, adjust pH to 7.2-7.4, sterilize at 121℃ for 30min.

[0058] R2A medium: KH2PO4 0.3g, MgSO4·7H2O 0.05g, sodium pyruvate 0.3g, soluble starch 0.5g, glucose 0.5g, casein hydrolysate 0.5g, peptone 0.5g, yeast extract 0.5g, adjust pH to 7.2, sterilize at 121℃ for 30min.

[0059] Inorganic salt medium (MSM): 0.5g NaNO3, 1.0g (NH4)2SO4, 2.5g Na2HPO4, 1.0g KH2PO4, 1mL micro-element stock solution (pH 7.0), sterilized at 121℃ for 30min. After cooling to room temperature, add 1mL vitamin solution and 1mL calcium-magnesium solution. Add atrazine at different concentrations as the sole nitrogen source according to the experimental design requirements.

[0060] Trace element stock solution: 108 mg Al2(SO4) 3· 18H2O, 56mg CoSO4·7H2O, 56mg CuSO4·5H2O, 3.0g FeSO4·7H2O, 611mg H3BO3, 28mg KBr, 56mg KI, 28mg LiCl, 389mg MnCl2·4H2O, 28mg Na2MoO4·2H2O, 28mg Na2WO4·2H2O, 58mg NiCl2·6H2O, 28mg SnCl2·2H2O, 34mg ZnSO4·H2O. Filter through a 0.2μm membrane and store at room temperature, protected from light.

[0061] Vitamin solution: 200mg para-aminobenzoic acid, 200mg biotin, 200mg folic acid, 200mg niacin, 100mg calcium pantothenate, 100mg pyridoxine hydrochloride, 100mg riboflavin, 100mg thiamine, 1mg vitamin B1 12 Store at room temperature, protected from light, through a 0.2μm filter membrane.

[0062] Calcium-magnesium solution: 30g CaCl2, 20g MgCl2. Sterilize at 121℃ for 20min, and store at room temperature away from light.

[0063] The corresponding solid separation and purification medium can be obtained by adding 20 g / L agar to the above liquid culture medium.

[0064] Experimental equipment: Agilent-1100 high-performance liquid chromatography (HPLC) system was used; column: Ultimate XB-C18 column (150 mm × 4.6 mm, 5 μm); mobile phase: methanol-water (80:20 v / v); flow rate: 1.0 mL / min. -1 Column temperature: 25℃, wavelength: 254nm, injection volume: 5μL.

[0065] The atrazine herbicide used in the examples was purchased from SIGMA (Shanghai, China).

[0066] The above implementation methods will be described in more detail below with reference to specific examples.

[0067] Example 1: Obtaining and Identifying Atrazine-Degrading Bacteria

[0068] 1. Isolation and screening of degrading bacteria FH-1

[0069] Weigh 10g of soil (sludge from the wastewater treatment pond of Nanjing Pesticide Factory) that has been contaminated with atrazine for a long time, and add it to a 250mL Erlenmeyer flask containing 100mL of inorganic salt medium containing 100mg / L atrazine. Incubate on a shaker (30℃, 150rpm) for 7 days. Take 10mL of the culture and inoculate it into 100mL of fresh inorganic salt medium containing 200mg / L atrazine. Continue incubation, continuously transferring the culture until the final atrazine concentration reaches 1000mg / L. Take 1mL of the bacterial culture and dilute it stepwise to 10... -2 10 -3 10 -4 10 -5 and 10 -6 Five concentration gradients were used, and each dilution was isolated using the spread plating method on solid inorganic salt medium containing 1000 mg / L atrazine. After two days of incubation at 30°C, single colonies were picked based on their different morphologies and characteristics, repeatedly streaked for purification, and strains with the same morphology were merged based on both colony appearance and microscopic observation. The resulting strains were then inoculated onto R2A solid medium slants for storage and future use. Finally, a strain capable of growing on isolation medium with 1000 mg / L atrazine was obtained and named HR8. Its colony morphology on R2A solid medium is shown in the figure below. Figure 1 As shown, the bacterial cell image under a thermal field emission scanning electron microscope is as follows: Figure 2 As shown.

[0070] Degradation zone experiment: Take 1 mL of bacterial suspension and inoculate it into a test tube containing 10 mL of R2A medium. Incubate on a shaker (30℃, 150 rpm) for 24 h. Use an inoculation loop to dip HR8 bacterial suspension from R2A medium and streak it onto a Petri dish containing 500 mg / L atrazine basal inorganic salt medium (MSM). After 5 days of incubation, the colonies that grow form atrazine dissolution zones at the bottom. Figure 3 As shown.

[0071] 2. Identification of HR8 degrading bacteria

[0072] (1) Morphological identification of the degrading bacterium HR8

[0073] The degrading bacteria HR8 obtained above through isolation and purification were inoculated onto solid LB medium and placed in a 30°C incubator for static culture. Single colonies in the logarithmic growth phase with stable colony size were selected for morphological description: the degrading bacteria HR8 grew rapidly on LB solid plate medium, with regular shape, round shape, smooth edges, pale yellow to yellow color, opaque, moist and viscous colonies that were easy to pick up, and mature colonies with a diameter of 0.5 cm.

[0074] (2) Homology analysis of 16S rDNA of degrading bacteria

[0075] 16S rDNA was extracted from strain HR8 and amplified using universal primers (27F (5'-AGAGTTTGATCCTGGCTCAG-3'), SEQ ID NO:1; 1492R (5'-GGTTACCTTGTTACGACTT-3'), SEQ ID NO:2). The PCR amplification program was as follows: pre-denaturation 95℃, 5 min; denaturation 95℃, 30 s; annealing 56℃, 30 s; extension 72℃, 1.5 min; final extension 72℃, 10 min; cycle number 35. A 50 μL amplification system consisted of 25 μL of 2×Taq Master Mix, 1 μL of genomic DNA, 1 μL each of 1492R and 27F primers, and sterile water to a final volume of 50 μL. After the reaction, the products were detected by 1% agarose gel electrophoresis and then sent to Sangon Biotech (Shanghai) Co., Ltd. for sequencing. Sequencing yielded the 16S rDNA sequence (SEQ ID NO:3) of strain HR8, consisting of 1390 base pairs. Alignment with the NCBI database was performed, and the results are as follows: Figure 4 As shown, the species with the highest sequence similarity to the species to be tested was Aquamicrobium lusatiense, with a sequence similarity of 99.78%.

[0076] Aquatic microbe HR8 16S rDNA (SEQ ID NO:3):

[0077]

[0078] Construction of the phylogenetic tree for strain HR8: Seven strains with high sequence similarity to strain HR8 were selected, and a phylogenetic tree for strain HR8 was constructed using MEGA5 software. The constructed phylogenetic tree is as follows: Figure 5 The strain with the highest similarity to strain HR8 is Aquamicrobium lusatiense, which is named Aquamicrobium HR8.

[0079] Example 2: Study on the degradation characteristics of the strain (different atrazine concentrations, inoculum sizes, temperatures, and pH)

[0080] 1. Construction of the atrazine standard curve

[0081] A standard curve for atrazine was prepared using high-performance liquid chromatography (HPLC). Specifically, the herbicide standard was serially diluted with methanol to obtain atrazine samples with concentrations of 1000 mg / L, 500 mg / L, 250 mg / L, 125 mg / L, 62.5 mg / L, and 31.25 mg / L. The diluted atrazine standards were filtered through a 0.22 μm microporous membrane and ultrasonically removed to remove air bubbles before injection and detection. The standard curve was constructed using a Cartesian coordinate system, with the peak area on the ordinate and the atrazine sample concentration on the abscissa. Concentrations and peak areas are shown in Table 1 and [Table data would be inserted here]. Figure 6 .

[0082] Table 1. Atrazine concentration and peak area in the samples.

[0083] Concentration mg / L Peak area 1000 4184.989 500 2108.286 250 1092.813 125 562.2705 62.5 288.3488 31.25 146.2462

[0084] From Table 1 and Figure 6 It can be seen that the standard curve for atrazine is y = 4.155x + 33.789, and R² = 0.9999.

[0085] The degradation rate is calculated as follows:

[0086]

[0087] 2. Study on the degradation characteristics of aquatic microorganism HR8

[0088] (1) Degradation curve of degrading bacteria HR8

[0089] The degrading strain HR8 was inoculated into an inorganic salt medium containing 200 mg / L atrazine and cultured at 30°C and 160 rpm in the dark for 48 hours. A control group (CK) was established under the same culture conditions but without inoculation with the degrading strain HR8. Culture media were collected every 6 hours, and the atrazine residue in both groups was determined by high-performance liquid chromatography (HPLC).

[0090] like Figure 7 As shown, strain HR8 has no lag period after inoculation and can completely degrade 200 mg / L atrazine within 48 hours.

[0091] (2) Effect of culture conditions on the degradation ability of HR8 degrading bacteria

[0092] The effects of different initial atrazine concentrations, initial inoculum amounts, temperatures, and pH on the degradation ability of the degrading bacterium HR8 were investigated.

[0093] Different initial atrazine concentrations: Atrazine concentrations in the culture medium were set at 50 mg / L, 100 mg / L, 200 mg / L, 400 mg / L, and 800 mg / L, respectively. The cultures were incubated at 10% inoculum at 30°C for 48 hours. The degradation rate of the strains under each condition was measured at 24 hours and 48 hours. At 24 hours of incubation, the degradation rates for the five treatments were 65.54%, 59.57%, 84.80%, 38.62%, and 10.14%, respectively. At 48 hours of incubation, the degradation rate of atrazine at initial concentrations of 50 mg / L, 100 mg / L, and 200 mg / L all reached 100%. Figure 8 As shown.

[0094] Initial inoculum size: The initial inoculum sizes of the strain were set at 2%, 5%, 10%, 15%, and 20% (v / v), with atrazine concentration of 400 mg / L, and incubated at 30℃ for 48 hours. The degradation rate of the strain under each condition was measured at 24 and 48 hours. At 24 hours of incubation, the degradation rate exceeded 50% for treatments with an inoculum size greater than 10%. At 48 hours of incubation, the degradation rate of the strain exceeded 50% for all inoculum sizes, with the 15% and 20% inoculum sizes achieving a degradation rate of 99%. Figure 9 As shown.

[0095] Culture temperature: The shaking incubators used for HR8 culture were set at 20℃, 25℃, 30℃, 35℃, and 40℃. At an inoculum size of 10% and an atrazine concentration of 400 mg / L, the cultures were cultured for 48 hours. The degradation rate of the strains under each condition was measured at 24 hours and 48 hours. At 24 hours of culture, the degradation rate of the strains exceeded 70% under the conditions of 25℃–35℃. At 48 hours of culture, the degradation rate of the strains was greater than 98% under the conditions of 25℃–35℃, 77.75% at 20℃, and 26.41% at 40℃. Figure 10 As shown.

[0096] pH: The pH of the inorganic salt medium was adjusted to 5, 6, 7, 8, and 9. At an inoculum size of 10% and an atrazine concentration of 400 mg / L, the cultures were incubated at 30°C for 48 hours. The degradation rate of the strains under each condition was measured at 24 and 48 hours. At 24 hours of incubation, the degradation rate did not exceed 50% under both acidic and alkaline conditions. At 48 hours of incubation, the degradation rate reached 100% at pH 7 and 55.82% at pH 8. These results indicate that pH has a significant impact on the degradation of atrazine. Figure 11 As shown.

[0097] Example 3: Preparation of Atrazine Bioremediation Agent

[0098] (1) The strain of water microbacterium HR8 was inoculated into an inorganic salt medium containing 200 mg / L and cultured at 30°C and 160 rpm until the logarithmic growth phase. The degradation rate was measured to obtain the degrading strain.

[0099] (2) The above-cultured strain was inoculated into R2A medium at a volume ratio of 15%, and cultured at 30°C and 160 rpm until the logarithmic growth phase to obtain the seed culture.

[0100] (3) Adding 20 mL of the obtained seed culture (OD600 = 2) to LB liquid fermentation medium can promote the high-density growth of the aforementioned aquatic microorganism HR8, reaching a viable count of 1 × 10⁻⁶. 4 ~1×10 8 The concentration is CFU / mL, and atrazine can be degraded.

[0101] Example 4: The effect of HR8 microbial agent on soil remediation

[0102] Weigh 1000g of soil, add atrazine aqueous solution and mix well to make the atrazine concentration in the soil 20mg / kg (i.e., prepare soil contaminated with atrazine). Add soil bioremediation agent containing HR8 strain (obtained from Example 3) at a ratio of 1×10 8 CFU / g was applied to the soil, thoroughly mixed, and placed in a dark incubator at 30℃ for constant temperature incubation. Samples were taken periodically to determine the residue of atrazine in the soil.

[0103] The results showed that the degradation rate of atrazine was significantly improved by using soil bioremediation agents containing HR8 strain. After 14 days, the degradation rate of atrazine in the soil with HR8 strain reached 65.92%, while the degradation rate of atrazine without strain was only 38.94% after 14 days.

[0104] The above description is only a preferred embodiment of the present invention and does not constitute a limitation on the scope of the claims. Other substantially equivalent substitutions that can be conceived by those skilled in the art are all within the protection scope of the present invention.

Claims

1. An isolated bacterium, said bacterium being *Aquamicrobium lusatiense*, characterized in that, The bacteria was named Aquamicrobium lusatiense HR8, with accession number CGMCC No. 28916.

2. A microbial agent, characterized in that, The bacterial agent includes the bacteria as described in claim 1.

3. The microbial agent as described in claim 2, characterized in that, The viable count of the bacteria in the bacterial agent is 1×10⁻⁶. 4 CFU / mL or higher.

4. The microbial agent as described in claim 2 or 3, characterized in that, The bacterial agent also includes a culture medium for culturing the bacteria and / or bacterial agent excipients.

5. The microbial agent as described in claim 4, characterized in that, The culture medium is LB medium or R2A medium; The excipients for the microbial agent are selected from one or more of the following: excipients, disintegrants, binders, thickeners, solubilizers, preservatives, lubricants, and freeze-drying protectants.

6. A method for culturing bacteria as described in claim 1, characterized in that, The method includes culturing the bacteria in a culture medium.

7. The method as described in claim 6, characterized in that, The method satisfies the following conditions: (1) The culture medium is LB medium or R2A medium; (2) The culture temperature is 20–40℃; (3) The culture time is 24 to 60 hours; (4) The pH of the culture is 5.0–9.0; (5) The rotation speed of the culture is 150–180 rpm; and, (6) The initial inoculum size for the culture is 2% (v / v) to 20% (v / v).

8. A method for preparing the microbial agent according to any one of claims 2-5, characterized in that, The method includes culturing the bacteria using the method described in claim 6 or 7.

9. A method for degrading triazine herbicides, characterized in that, The method includes: applying the bacteria as described in claim 1 or the microbial agent as described in any one of claims 2-5 to an area contaminated by the triazine herbicide; The triazine herbicide in question is atrazine.

10. The method as described in claim 9, characterized in that, In the bacteria or the bacterial agent, the viable count of the bacteria is 1 × 10⁻⁶. 4 CFU / g or higher.

11. The method as described in claim 9 or 10, characterized in that, The bacteria or the bacterial agent degrade the triazine herbicide under the following conditions: (1) The temperature is 20-40℃; (2) The time is more than 2 days; and, (3) pH is 5.0 to 9.

0.

12. The use of the bacteria as described in claim 1 or the microbial agent as described in any one of claims 2-5 in the degradation of triazine herbicides; The triazine herbicide mentioned is atrazine.

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