Bacillus velezensis fl-3 and application thereof

Abstract

The application discloses bacillus velezensis FL-3 and application thereof, the bacillus velezensis FL-3 is preserved in Guangdong Microbial Culture Collection Center, the preservation date is December 18, 2023, the preservation number is GDMCC No: 64155, and the preservation address is No. 59, Building 5, 100, Xianlie Middle Road, Guangzhou.The application is separated to the soil of rape field applied with trifluralin by enrichment domestication separation method, obtains trifluralin high-efficiency degradation bacteria FL-3, and FL-3 is bacillus velezensis by morphological and molecular identification, and the degradation rate of FL-3 to trifluralin is 80.81% in 14d, the optimum degradation condition of FL-3 is 35 DEG C, pH is 8, inoculation amount is 5%, and the degradation rate of 14d degradation strain to trifluralin is 82.59%.

Description

Technical Field

[0001] This invention relates to a Bacillus species, specifically to Bacillus belesii FL-3 and its applications. Background Technology

[0002] Trifluralin, chemically known as 2,6-dinitro-N,N-dipropyl-4-trifluoromethylaniline, has the molecular formula C2. 13 H 16 F3N3O4 is a dinitroaniline selective pre-emergence herbicide that is currently widely used.

[0003] In practical agricultural production, trifluralin is generally formulated as an emulsifiable concentrate. Besides its widespread use in farmland, it is also widely used in aquaculture. Trifluralin is safe, highly effective, and has a broad spectrum of herbicidal and control properties, making it widely used in agricultural production. Trifluralin is readily soluble in most organic solvents such as hexane, ethanol, acetonitrile, ethyl acetate, xylene, and acetone. Under natural conditions, trifluralin is easily volatile and photodegraded. In soil, however, it is usually fixed to the soil due to adsorption by soil colloids, making it less mobile and less prone to volatilization.

[0004] Trifluralin's mechanism of action is primarily through entry into the coleoptile structure of grassy weeds, while for some dicotyledonous weeds it is absorbed via the hypocotyl. Microtubules in plants can polymerize and participate in cell division. After entering the cell, trifluralin first inhibits the development of microtubule tissue, disrupting normal metabolic activities in weed cells and hindering mitosis, thus causing weed death. It is noteworthy that due to its poor leaching properties, trifluralin readily interacts with active groups in soil organic matter to form difficult-to-degrade bound compounds, causing delayed soil pollution and harming the growth and development of subsequent crops. Trifluralin can also toxicize and affect the genes of mammals, and its carcinogenicity is classified as Group C. The U.S. Environmental Protection Agency classifies trifluralin as a persistent bioaccumulator. While some European countries have restricted or even banned the use of trifluralin, its relatively high cost-effectiveness means it remains a commonly used agricultural herbicide in my country.

[0005] The use of pesticides has significantly improved agricultural production efficiency in my country. Pimentel et al. (Amounts of pesticides reaching target pests: Environmental impacts and ethics[J]. Journal of Agricultural & Environmental Ethics, 1995, 8(1): 17-29) studied the fate of pesticides in the environment and found that only a small amount of pesticides can be directly used to control weeds, while more than 99% of pesticides are released directly or indirectly into the natural environment. These pesticides released into the natural environment will then accumulate in surface water through atmospheric and water cycles, affecting the ecological environment and even threatening the safety of drinking water. A large portion of these pesticides will also be adsorbed into the soil by soil colloids and undergo degradation and transformation by various factors such as microorganisms. Trifluralin plays a vital role in agricultural production in my country, but its extensive use has become one of the important causes of soil pollution in my country. The impact of trifluralin on soil microorganisms is also significant, specifically affecting the quantity and distribution of soil microorganisms, altering their community structure, reducing their metabolic activity, and inhibiting the activity of certain enzymes in the soil. The effects of trifluralin as an exogenous pollutant on soil microorganisms have been confirmed by numerous studies, and there are also many researches on its impact on the nitrogen cycle in soil.

[0006] Trifluralin can be degraded through physical, chemical, or biological reactions. Under experimental conditions, the main degradation pathways of trifluralin in soil include photolysis, volatilization, and leaching. Photolysis and volatilization are two important degradation pathways. However, trifluralin is difficult to photolyze and volatilize at soil depths below 0.2m, and mainly relies on microbial degradation. Microbial degradation is the most important pathway for trifluralin degradation. Several fluroxypyr degrading bacteria have been studied and reported both domestically and internationally. For example, Bellinaso (Biodegradation of the herbicide trifluralin by bacteria isolated from soil[J]. Fems Microbiology Ecology,2003,43(2):191-194) isolated eight fluroxypyr degrading strains from soil that had been continuously treated with fluroxypyr for 40 years and tested the degradation ability of these strains for fluroxypyr. Finally, four strains with significant degradation effects on fluroxypyr were screened out, namely Klebsiella sp., Herbaspirillum sp., and two Bacillus strains, with degradation rates of 24.60%, 16.40%, 25.00%, and 18.40%, respectively. Sato Yoko et al. (Degradation of Trifluralin by Bacteria Isolated from Soil[J]. Weed Research, 1992, 37(3): 213-219) isolated two trifluralin-degrading bacteria from soil and tested their ability to degrade trifluralin. Ni Haiyan (Isolation, Identification, Degradation Pathway Analysis and Nitroreductase Gene Cloning of Pendimethalin-Degrading Strains[D]. Nanjing Agricultural University. 2016) isolated a Bacillus subtilis Y3 strain from soil and extracted the functional gene PNR from it, verifying that this gene can degrade trifluralin. Ji Li et al. (Isolation, Identification and Degradation Characteristics of Trifluralin-Degrading Strains[J]. Jiangsu Agricultural Sciences. 2016, (3): 390-393) isolated a strain Leucobacter that degrades trifluralin from aquaculture water. Erguven et al. (The capacity of some newlybacteria and fungi for biodegradation of herbicide trifluralin under agiated culture media[J]. Cellular and Molecular Biology (Noisy-le-Grand, France), 2016, 62(6):74) isolated 11 bacteria and fungi that can degrade trifluralin.

[0007] Currently, there is limited research on the degradation characteristics of trifluralin-efficient strains. Summary of the Invention

[0008] The purpose of this invention is to provide a Bacillus berberis FL-3 and its application, which can effectively degrade trifluralin.

[0009] To achieve the above objectives, the present invention provides a Bacillus velezensis FL-3, which is deposited at the Guangdong Provincial Center for Microbial Culture Collection, date of deposit: December 18, 2023, accession number: GDMCC No: 64155, address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

[0010] Another object of the present invention is to provide the application of the aforementioned Bacillus berberis FL-3 in the degradation of fluroxypyr.

[0011] Preferably, the seed culture of Bacillus berberis FL-3 is used to degrade trifluralin.

[0012] Preferably, the OD of the seed culture of Bacillus belyi FL-3 is... 600 Version 1.0 and above.

[0013] Preferably, the seed culture of Bacillus belye FL3 is used to degrade trifluralin at a temperature of 25–40°C, a pH of 7–9, an inoculum amount of 2–5%, a trifluralin concentration of 0.1–1 mg / L, and a degradation time of more than 7 days.

[0014] Another object of the present invention is to provide a degrading agent containing the aforementioned Bacillus freundii FL-3 for degrading fluroxypyr.

[0015] The Bacillus belyssus FL-3 of the present invention and its application have the following advantages:

[0016] This invention uses an enrichment and domestication separation method to isolate trifluralin-treated rapeseed soil and obtain FL-3, a highly efficient trifluralin-degrading bacterium. Morphological and molecular identification confirmed that FL-3 is Bacillus belye. FL-3 showed a trifluralin degradation rate of 80.81% after 14 days. After optimization of degradation conditions, the optimal degradation conditions for FL-3 were 35℃, pH 8, and inoculum size of 5%. After 14 days, the degradation rate of trifluralin by the degrading strain was 82.59%. Attached Figure Description

[0017] Figure 1 This shows the colony morphology of the FL-3 degrading strain of the present invention.

[0018] Figure 2The Gram staining results are for the FL-3 degrading strain of this invention.

[0019] Figure 3 This is a phylogenetic tree diagram of the FL-3 degrading strain of the present invention.

[0020] Figure 4 The growth curve of the FL-3 degrading strain of the present invention is shown.

[0021] Figure 5 This invention investigates the effect of different culture temperatures on the degradation ability of FL-3 degrading strains.

[0022] Figure 6 This invention investigates the effect of different pH values ​​on the degradation ability of FL-3 degrading strains.

[0023] Figure 7 This invention investigates the effect of different inoculum amounts on the degradation ability of FL-3 degrading strains.

[0024] Figure 8 This invention investigates the effect of different substrate concentrations on the degradation ability of FL-3 degrading strains.

[0025] Figure 9 This invention relates to the effect of different culture times on the degradation ability of FL-3 degrading strains. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The reagents and culture media used in the following experimental examples:

[0028] The purity of the trifluralin standard was 99.3% (Shenyang Chemical Research Institute Pesticide Testing Laboratory); the soil sample came from a rapeseed field where trifluralin was applied by the Qinghai Academy of Agricultural and Forestry Sciences.

[0029] LB medium: 3g meat extract, 10g peptone, 5g lactose and 0.024g bromothymol blue, pH=7.0, sterilized at 115℃ for 30min; solid medium with 1.5% agar added.

[0030] Modified Martin medium: 2g yeast extract, 20g glucose, 5g peptone, 1g dipotassium hydrogen phosphate and 0.5g magnesium sulfate, pH=6.4±0.2, sterilized at 121℃ for 30min; solid medium with 1.5% agar added.

[0031] Gao's No. 1 medium: 0.5g sodium chloride, 20g soluble starch, 1g potassium nitrate, 0.5g dipotassium hydrogen phosphate, 0.01g ferrous sulfate and 0.244g anhydrous magnesium sulfate, sterilized at 121℃ for 30min; solid medium is supplemented with 1.5% agar.

[0032] Inorganic salt culture medium: ammonium sulfate 0.4g, ammonium nitrate 1.2g, potassium dihydrogen phosphate 0.5g, dipotassium hydrogen phosphate 1.5g, magnesium sulfate 0.5g, sodium chloride 0.5g and yeast extract 0.05g, pH 7.0, sterilized at 121℃ for 30min; solid culture medium with 1.5% agar added.

[0033] Experiment Example 1: Screening of Degrading Strains

[0034] 1. Screening of degrading strains

[0035] Weigh 1g of soil enriched with trifluralin and add 9mL of sterile water to prepare a soil suspension. Dilute with sterile water sequentially to obtain 10... -4 ~10 -1 Soil suspensions of different concentrations were plated (0.1 mL each) onto three solid agar plates (LB, Modified Martin, and Gao's No. 1) containing 1 mg / L trifluralin. Three replicates were made for each medium. After incubation at 30°C for 3 days, colony growth on the plates was observed. Single colonies were picked from the plates and streaked repeatedly until pure cultures and single colonies appeared. Each colony was numbered and stored in the corresponding solid agar slant.

[0036] Strains with the potential to degrade trifluralin, obtained through domestication, were inoculated into three liquid culture media (LB, modified Martin, and Gao's No. 1) and cultured for 3 days to obtain seed culture. The seed culture was then inoculated at a 1% inoculation rate into the three liquid culture media containing 1 mg / L trifluralin and cultured at 30°C with shaking at 180 rpm. Samples were taken every 1, 3, 5, 7, and 14 days, with each culture medium containing the same concentration of trifluralin but without inoculation serving as a control. After pretreatment according to the culture medium pretreatment method, the degradation rate of trifluralin by each strain was analyzed using GC-ECD.

[0037] The above-mentioned culture medium pretreatment method is as follows: Measure 10 mL of LB, modified Martin, or Gao's No. 1 culture medium (accurate to 0.01 mL), add 10 mL of n-hexane, vortex for 3 min to mix, add 4 g MgSO4 and 1 g NaCl, vortex for 1 min. Centrifuge at 5000 rpm for 5 min, take 1.5 mL of the supernatant and place it in a purified centrifuge tube (containing 100 mg MgSO4 and 100 mg PSA), vortex for 1 min, centrifuge at 12000 rpm for 2 min, and filter the supernatant through a 0.22 μm filter membrane for GC-ECD detection.

[0038] The formula for calculating the degradation rate is as follows:

[0039] Q(%)=(C0-C t ) / C0×100%

[0040] In the formula, Q is the degradation rate of trifluralin (%); C0 is the initial concentration of trifluralin (mg / L); C t The residual trifluralin content (mg / L) in the culture medium after the culture is completed.

[0041] A total of 22 bacterial strains were screened in the experiment. Among them, strains FL-3, FL-5, and FL-6 showed significant differences from their corresponding blank control groups, indicating that these three strains had a degrading effect on trifluralin. Specifically, the degradation rates of strain FL-3 at 1d, 3d, 5d, 7d, and 14d were 19.58%, 51.99%, 58.37%, 78.99%, and 80.81%, respectively. The trifluralin concentration in each culture medium gradually decreased with the extension of treatment time. The trifluralin concentration in the culture medium of strain FL-3 decreased most rapidly within 3 days, from an initial concentration of 1 mg / L to 0.39 mg / L.

[0042] 2. Identification of degrading strains

[0043] (1) Morphological identification

[0044] The isolated and purified strains were streaked on solid plates and incubated at 30°C. The morphology of the colonies growing on the plates was observed. Strain FL-3 was incubated on LB medium for 24 hours. Sterile water was spotted onto glass slides, and a small amount of spores were picked up with a needle, evenly dispersed, and spread in water. After fixation, Gram staining was performed, and the morphology of the strains was observed under a 100× optical microscope with an oil immersion lens.

[0045] The colony morphology of strain FL-3 is as follows Figure 1 As shown, FL-3 colonies are pale yellow with an irregular, rough, and wrinkled surface.

[0046] like Figure 2 As shown, the Gram staining result of FL-3 is purple, indicating that FL-3 is a Gram-positive bacterium, and all of them are short rod-shaped.

[0047] (2) Molecular identification

[0048] Genomic DNA was extracted from strain FL-3 and amplified by PCR using universal bacterial primers 27F / 1492R, gyrA, gyrB, and rpoB (Table 1). The amplified products were sequenced. After obtaining the sequences, the obtained gene sequences were entered into the NCBI website through the Blast window for homology alignment. A phylogenetic tree of all genes was constructed using Phylosuite software.

[0049] Table 1 shows the primer information.

[0050]

[0051] Strain FL-3 was amplified using universal bacterial primers 27F / 1492R, gyrA, gyrB, and rpoB, yielding nucleotide fragments of 1415 bp, 993 bp, 1040 bp, and 1155 bp. The obtained sequences were uploaded to the GenBank database for BLAST alignment analysis. Strains with high homology were selected for phylogenetic tree analysis. The results showed that FL-3 clustered with Bacillus velezensis Q6 (OQ181207.1) in the same branch. Figure 3 Based on morphological and molecular biological identification, strain FL-3 was identified as Bacillus velezensis.

[0052] The above-mentioned strain FL-3 (Bacillus velezensis FL-3) is deposited at the Guangdong Provincial Microbial Culture Collection Center, date of deposit: December 18, 2023, accession number: GDMCC No: 64155, address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

[0053] 3. Growth curve of the strain

[0054] The selected FL-3 cells were inoculated into LB liquid medium using an inoculation loop and cultured at 30℃ and 180 rpm with shaking for 12 h to obtain the seed culture. 1% of the seed culture was then inoculated into fresh LB liquid medium and cultured at 30℃ and 180 rpm with shaking. The OD of the fermentation broth was measured every 2 h. 600 The growth curve of the strain was plotted using blank LB liquid medium as a control.

[0055] like Figure 4 As shown, FL-3 is in a slow growth phase from 0 to 8 hours; it enters a rapid growth phase from 8 to 10 hours; it enters a stable growth phase from 12 to 36 hours; and it enters a decline phase from 36 to 48 hours.

[0056] Experimental Example 2: Single-Factor Degradation Characteristics

[0057] Strain strain FL-3 was inoculated into 250 mL of LB liquid medium using an inoculation loop and cultured at 28 °C and 180 rpm for 12 h with shaking to obtain the seed culture. 1% of the seed culture was then inoculated into fresh LB liquid medium and cultured at 30 °C and 180 rpm with shaking until the logarithmic growth phase (OD50) was reached. 600 =1.0) was used as the seed liquid, and its degradation characteristics were studied, as follows:

[0058] 1. Effect of temperature on the degradation of trifluralin by bacterial strains

[0059] The seed culture of strain FL-3 was inoculated at a rate of 3% into LB liquid medium containing 1 mg / L trifluralin. The initial pH was adjusted to 7.0, and the culture temperatures were set at 20℃, 25℃, 30℃, 35℃, and 40℃, with each treatment replicated three times. The culture was carried out in a shaker at 180 r / min in the dark for 14 days, and the degradation of trifluralin was measured at 1, 3, 5, 7, and 14 days.

[0060] The results are as follows Figure 5 As shown, after inoculation, the degradation rate of trifluralin by the strain increased with increasing temperature, with the best degradation effect at 35℃. FL-3 exhibited the lowest degradation ability at 20℃. This may be because lower or higher temperatures affect bacterial growth, leading to lower enzyme activity and thus affecting the strain's ability to degrade trifluralin. The degradation rate of the strain was fastest from 1 to 7 days, and slowed significantly after 7 days. The degradation rate of FL-3 at 35℃ for 7 days was 79.96%; from 7 to 14 days, the degradation rate of FL-3 at 35℃ for 14 days was 86.91%.

[0061] 2. Effect of pH on the degradation of trifluralin by bacterial strains

[0062] The seed culture of strain FL-3 was inoculated at a rate of 3% into LB liquid medium containing 1 mg / L trifluralin. The culture temperature was set at 30℃, and the initial pH of the liquid medium was adjusted to 4, 5, 6, 7, 8, and 9. Each treatment was replicated three times. The culture was carried out in a shaker at 30℃ and 180 r / min in the dark for 14 days. The degradation rate of trifluralin was measured at 1, 3, 5, 7, and 14 days.

[0063] The results are as follows Figure 6 As shown, 14 days after inoculation, the degradation rate of trifluralin by the strain increased with increasing pH, with the fastest degradation rate observed between days 1 and 7. pH had no significant effect on the degradation rate of FL-3. The degradation rate of trifluralin gradually slowed down with increasing degradation days. At 14 days, FL-3 showed the best degradation effect on trifluralin at pH 7 and 8, with degradation rates reaching 84.02% and 85.19%, respectively.

[0064] 3. Effect of inoculum size on the degradation of trifluralin by the strain

[0065] Seed culture of strain FL-3 was inoculated into LB liquid medium containing 1 mg / L trifluralin at inoculation rates of 1%, 2%, 3%, 4%, and 5%, respectively. The initial pH was adjusted to 7.0. The control group was added with 5% sterile water. The cultures were incubated in a shaker at 30℃ and 180 r / min under light for 14 days. The degradation rate of trifluralin was measured at 1, 3, 5, 7, and 14 days.

[0066] The results are as follows Figure 7 As shown, the degradation rate of trifluralin by FL-3 increased with increasing inoculum size. At 7 days, the degradation effect was best with an inoculum size of 5%, reaching 76.82%. With increasing degradation time, the degradation rate gradually slowed down. At 14 days, FL-3 showed the best degradation effect with an inoculum size of 4%, reaching 85.19%. The experimental results indicate that both excessively high and low inoculum sizes affect the degradation ability of the strain. With low inoculum sizes, the growth cycle of the strain is longer; with excessive inoculum sizes, the number of strains gradually increases with the metabolic process, leading to competition for nutrients and oxygen, resulting in nutrient deficiency during degradation and affecting the growth and reproduction of the strain.

[0067] 4. Effect of substrate concentration on the degradation of trifluralin by the strain

[0068] The seed culture of strain FL-3 was inoculated at a rate of 3% into LB liquid medium containing 0.1 mg / L, 1 mg / L, and 10 mg / L trifluralin. The initial pH was adjusted to 7.0, and each treatment was replicated three times. The culture was carried out in a shaker at 30℃ and 180 r / min in the dark for 14 days. The degradation rate of trifluralin was measured at 1, 3, 5, 7, and 14 days.

[0069] The results are as follows Figure 8 As shown, the degradation ability of LF-3 at concentrations of 0.1 and 1 mg / L did not differ significantly. However, the degradation effect of the strain on trifluralin decreased significantly with increasing concentration to 10 mg / L. When the trifluralin concentration was 0.1 mg / L, the degradation rate of FL-3 was 81.07% after 14 days; when the concentration increased to 1 mg / L, the degradation rate was 83.01% after 14 days; and when the substrate concentration was 10 mg / L, the degradation rate was only 31.36% after 14 days. Therefore, it can be preliminarily concluded that the strain exhibits better degradation efficiency between concentrations of 0.1 and 1 mg / L.

[0070] 5. Effect of culture time on the degradation of trifluralin by the strain

[0071] The seed culture of strain FL-3 was inoculated at a rate of 3% into LB liquid medium containing 1 mg / L trifluralin. The initial pH was adjusted to 7.0. The control group was treated with 5% sterile water. Each treatment was repeated three times. The culture was carried out in a shaker at 30°C and 180 r / min under light for 1, 3, 5, 7, 14, 21, and 28 days. The residual amount of trifluralin was measured after the culture was completed.

[0072] The results are as follows Figure 9 As shown, the degradation rate of trifluralin by strain FL-3 increased with time, and the degradation rate showed a relatively rapid trend from 1 to 7 days, followed by a decrease from 7 to 28 days. The degradation rates of trifluralin by FL-3 at 1, 3, 5, 7, 14, and 28 days were 18.43%, 27.29%, 59.12%, 73.19%, 80.63%, 86.92%, and 90.37%, respectively. At 28 days of degradation culture, the degradation rate of FL-3 was 78.37% higher than that of the control (CK).

[0073] 6. Response surface optimization

[0074] Based on the single-factor experiments, degradation temperature (°C), pH, and inoculum size (%) were selected as independent variables, and the degradation rate of trifluralin was used as the response value. A Box-Behnken three-factor, three-level experiment was designed with a total of 17 experimental sites to explore the optimal degradation conditions of trifluralin-degrading strains.

[0075] (1) Equation analysis of response surface regression equation

[0076] Based on the single-factor experiments, a Box-Behnken experiment was conducted using temperature, pH, and inoculum size. The experimental design and results of the FL-3 response value are shown in Tables 2 and 3. The degradation rate of trifluralin in the tables was fitted, and the equation of the conditional regression model for FL-3 degradation of trifluralin is as follows:

[0077] Y=83.44-5.57A-1.73B+4.49C+6.57AB+3.27AC+3.78BC-3.37A 2 -7.76B 2 -2.5

[0078] 2C 2

[0079] The formula shows that the effects of the three factors on the degradation of trifluralin during the FL-3 degradation process are not in a conventional linear relationship, indicating that there are interactive effects among the factors during the degradation process of the strain.

[0080] An analysis of variance was performed on the FL-3 regression equation, and the results are shown in Table 4. The F-value of the model was 35.96, P < 0.0001, indicating that the model has high reliability. The P-value for the lack-of-fit term was 0.2037 > 0.05, indicating that the lack-of-fit term was not significant and there were no factors causing the lack of fit. The linear terms A, B, and C and the quadratic term A... 2 B 2 C 2 The p-values ​​for the interaction terms AB, AC, and BC were all <0.05, indicating that each factor had a significant impact on the response results. Analysis of variance showed that the order of influence of the three factors on the trifluralin degradation rate was A > C > B, i.e., temperature > inoculum size > pH value. Table 5 shows the fitting results of the response data. Table 5 shows that the coefficient of determination R of the regression equation... 2 The value is 0.9788, indicating that the model can explain 97.88% of the response value variations. Adjusted R-value. 2 The value of 0.9516 indicates that over 95.16% of the variation in the trifluralin degradation rate in the quadratic response surface model originates from the influence of temperature, pH, and inoculum size, demonstrating a good fit of the regression equation model. The CV (CV) of 2.35% < 10% indicates high reliability and accuracy of the experimental results. The Adeq Precision (17.4822 > 4) further confirms the model's rationality and reliability. The predicted variance R0 is [not specified in the original text]. 2 With Adjusted Variance R 2 The fact that both values ​​are high and the difference is less than 0.2 indicates that the model can fully simulate the experimental process.

[0081] Table 2 shows the Box-Behnken experimental factors and levels for optimizing the conditions for FL-3 degradation of fluroxypyr.

[0082]

[0083] Table 3 shows the Box-Behnken experimental design and results for optimizing the degradation conditions of FL-3 on fluroxypyr.

[0084]

[0085] Table 4 shows the analysis of variance of the FL-3 response surface methodology results.

[0086]

[0087]

[0088] Table 5 shows the fitting results of the FL-3 response data.

[0089]

[0090] The above analysis of the response surface methodology reveals that the optimal conditions for FL-3 degradation of trifluralin are: 35℃, pH 8.1093, and inoculum size of 5%, with a predicted degradation rate of 82.12%. Revising the degradation conditions to 35℃, pH 8, inoculum size of 5%, and substrate concentration of 1 mg / L, the degradation time under these conditions was 14 days, yielding an actual trifluralin degradation rate of 82.59%.

[0091] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A Bacillus velezensis FL-3 strain, characterized in that, This Bacillus belyss FL-3 is deposited at the Guangdong Provincial Center for Microbial Culture Collection, date of deposit: December 18, 2023, accession number: GDMCC No: 64155, address: 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

2. The application of Bacillus berberis FL-3 as described in claim 1 in the degradation of fluroxypyr.

3. The application according to claim 2, characterized in that, The seed culture of Bacillus flavonoids FL-3 was used to degrade trifluralin.

4. The application according to claim 3, characterized in that, OD of the seed culture of Bacillus belyss FL-3 600 Version 1.0 and above.

5. The application according to claim 3, characterized in that, The seed culture of Bacillus belye FL3 was used to degrade trifluralin at a temperature of 25–40°C, a pH of 7–9, an inoculum size of 2–5%, a trifluralin concentration of 0.1–1 mg / L, and a degradation time of more than 7 days.

6. A degrading agent containing Bacillus freundii FL-3 as described in claim 1 for degrading fluroxypyr.

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