Pseudomonas stutzeri SND-1 strain as well as culture method and application thereof

Abstract

The invention discloses a pseudomonas stutzeri SND-1 strain as well as a culture method and application thereof. According to the invention, a broad-salt synchronous nitrification and denitrification functional strain SND-1 capable of efficiently degrading nitrogen concentration in an aquaculture water body is separated from a prawn aquaculture pond, and the strain is identified as Stutzeria stutzeri according to colonial morphology and 16S rDNA gene sequencing analysis and phylogenetic analysis, the pseudomonas stutzeri SND-1 strain is preserved in the China Center for Type Culture Collection (the preservation number is CCTCC NO: M 20242216) on October 15, 2024, and the pseudomonas stutzeri SND-1 strain is preserved in the China Center for Type Culture Collection (CCTCC). The pseudomonas stutzeri SND-1 strain belongs to heterotrophic ammonia oxidizing bacteria, has a heterotrophic nitrification-aerobic denitrification function, can efficiently degrade ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen in fresh water, seawater and aerobic environments, has no toxic effect on aquatic animals, and can be applied to ecological restoration of fresh water or seawater water environments.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of microbial technology, and particularly relates to a Pseudomonas stutzeri SND-1 strain and a culture method and application thereof. BACKGROUND

[0002] In recent years, with the increasing scale of freshwater and seawater aquaculture, high-density aquaculture mode brings higher aquaculture output, but also brings a large amount of residual feed and excrement to the aquaculture water, leading to eutrophication and excessive growth of algae in the water, forming water bloom, and further causing water hypoxia, acidification and other problems. Ammonia nitrogen, as an important inorganic substance in the nitrogen cycle, is one of the main factors leading to water eutrophication. The methods for removing ammonia nitrogen mainly include chemical drug oxidation method, physical adsorption method, flocculation sedimentation method and biological method.

[0003] At present, the most economical and effective method for removing ammonia nitrogen is biological method, and the main process is to convert ammonia nitrogen into nitrogen gas through the action of a series of microorganisms, which is completed by nitrifying bacteria and denitrifying bacteria in most wastewater treatment facilities, that is, ammonia nitrogen is first oxidized to nitrite nitrogen and nitrate nitrogen by aerobic autotrophic nitrifying bacteria, and then nitrate nitrogen is reduced to nitrogen gas by anaerobic heterotrophic denitrifying bacteria. Since Winogradsky first discovered the ammonia oxidation of bacteria in 1890, researchers have paid great attention to the mechanism and separation and purification method of ammonia-oxidizing bacteria. The ammonia oxidation of ammonia-oxidizing bacteria includes two oxidation processes, which utilize their own ammonia mono oxygenase (AMO) and hydroxylamine oxidoreductase (HAO) to react, and finally oxidize ammonia nitrogen to nitrite nitrogen.

[0004] Most of the ammonia-oxidizing bacteria existing in natural water bodies belong to gram-negative obligate chemotrophic autotrophic bacteria, which have the disadvantages of slow growth rate and difficulty in forming dominant bacterial flora; heterotrophic bacteria have the advantage of faster growth rate than autotrophic bacteria, and the population is more likely to quickly expand to form a dominant bacterial flora. In order to efficiently and quickly degrade the nitrogen concentration in water, it is urgent to isolate and screen out heterotrophic ammonia-oxidizing bacteria harmless to aquatic economic animals. SUMMARY

[0005] In view of the above technical problems, the present application provides a Pseudomonas stutzeri SND-1 strain and a culture method and application thereof, which can degrade the ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen concentration in water under aerobic environment, and has no toxic and harmful effects on human and cultured organisms. It has the advantages of good degradation effect, high efficiency and no secondary pollution.

[0006] The present application is implemented as follows:

[0007] A first object of the present application is to provide a Stutzerimonas stutzeri SND-1 strain, which was deposited with the China Center for Type Culture Collection on October 15, 2024, at an address of No. 299, Bajiyi Road, Wuchang District, Wuhan City, Hubei Province, Wuhan University, and has a preservation number of CCTCC NO: M 20242216.

[0008] Further, a culture of the above-mentioned Stutzerimonas stutzeri SND-1 strain.

[0009] The term "culture" refers to a collective term for a liquid or solid product (all substances in the culture container, fermentation product) that grows a microbial population after being artificially inoculated and cultured. That is, a product obtained by growing and / or amplifying microorganisms, which can be a biologically pure culture of microorganisms, or can contain a certain amount of culture medium, metabolites or other components produced during the culture process.

[0010] Further, the above-mentioned Stutzerimonas stutzeri SND-1 strain or the culture of the above-mentioned Stutzerimonas stutzeri SND-1 strain is applied in the preparation of a microbial agent.

[0011] Preferably, the application is to reduce the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen in water under euryhaline conditions.

[0012] Further, the above-mentioned Stutzerimonas stutzeri SND-1 strain or the culture of the above-mentioned Stutzerimonas stutzeri SND-1 strain is applied in the preparation of a microbial agent.

[0013] Preferably, the application is to reduce the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen in water under euryhaline conditions.

[0014] A second object of the present application is to provide a microbial agent, which comprises the above-mentioned Stutzerimonas stutzeri SND-1 strain or the culture of the above-mentioned Stutzerimonas stutzeri SND-1 strain.

[0015] A third object of the present application is to provide a microecological preparation, which comprises the above-mentioned Stutzerimonas stutzeri SND-1 strain or the culture of the above-mentioned Stutzerimonas stutzeri SND-1 strain.

[0016] A fourth object of the present application is to provide a culture method of the above-mentioned Stutzerimonas stutzeri SND-1 strain, which is placed in an LB liquid medium and continuously cultured at 28-37℃ and 180r / min for 18-36h.

[0017] The present application has the following advantages:

[0018] The present application provides a Pseudomonas stutzeri SND-1 strain which can degrade the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen in aquaculture wastewater under freshwater or seawater conditions. The strain belongs to a euryhaline aerobic heterotrophic bacterium and can degrade the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen in freshwater or seawater under aerobic conditions. It has no toxic effects on aquatic animals, has the advantages of wide application conditions, good degradation effect, high efficiency and no secondary pollution, and can be used to improve the water environment under aerobic conditions.

[0019] The main difference and advantage of the Pseudomonas stutzeri SND-1 strain of the present application and the strains disclosed in the prior art (patent numbers CN201910882118.4, CN200610020315., CN202110624074.2, CN200910273046.X and CN201210151039.4, etc.) are:

[0020] (1) The ammonia nitrogen removal rate of the Pseudomonas stutzeri SND-1 strain of the present application is significantly faster than that of the existing strains, which can achieve the effect of quickly removing ammonia nitrogen in a short time, and the ammonia nitrogen removal rate is higher.

[0021] (2) The Pseudomonas stutzeri SND-1 strain of the present application has euryhalinity and can efficiently degrade ammonia nitrogen in freshwater or seawater (salinity range 0-35) environment, and has a wider application range; and has the functions of simultaneous heterotrophic nitrification and aerobic denitrification, and can also efficiently degrade nitrite nitrogen, nitrate nitrogen and total nitrogen concentration.

[0022] (3) The Pseudomonas stutzeri SND-1 strain of the present application is isolated from prawn culture ponds and has no toxic effects on aquatic animals when applied in aquaculture water, and can be widely used in aquatic animal breeding scenes.

[0023] DEPOSIT DESCRIPTION

[0024] Address of deposit: No. 299, Bayi Road, Wuchang District, Wuhan, Hubei Province, China

[0025] Date of deposit: October 15, 2024

[0026] Name of strain: Pseudomonas stutzeri

[0027] Latin name: Stutzerimonas stutzeri

[0028] Strain number: SND-1

[0029] Depository: China Center for Type Culture Collection

[0030] Abbreviation of depository: CCTCC

[0031] CCTCC NO: M 20242216 BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Figure 4 is a phylogenetic tree based on 16S rDNA of Pseudomonas stutzeri SND-1 strain.

[0033] Figure 2 Figure 5 is a growth curve of Pseudomonas stutzeri SND-1 strain. DETAILED DESCRIPTION

[0034] In order to better understand the present application, the present application is further described in detail below in conjunction with examples and drawings, which are provided for those skilled in the art to understand, and the following examples are not a limitation on the scope of protection of the present application, and any changes and variations made on the basis of the present application are within the scope of protection of the present application.

[0035] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0036] The materials, reagents, etc. used in the following examples are commercially available unless otherwise specified.

[0037] Example 1 Isolation and screening of Pseudomonas stutzeri SND-1 strain

[0038] S1. Sampling: The strain sample of this experiment is an active mud sample from a pond, which is collected from a certain shrimp mariculture farm in Fujian. The collected mud sample is immediately stored in a 4°C refrigerator for standby use.

[0039] S2. Enrichment culture: 10g of mud sample is weighed and added with 100ml of sterile water to stir uniformly to mix mud and water. After standing for 5 minutes, 10ml of supernatant is aspirated and placed in 100ml of MA sterilized culture medium, which is cultured under the condition of 37°C and 180r / min for 5d.

[0040] MA culture medium: anhydrous glucose 5.0g, ferric citrate 0.1g (boiled with heat), Na2SO4 3.24g, MgCl2 5.9g, KCl 0.55g, CaCl2 1.8g, NaHCO3 0.16g, NaCl 20g, H2O 1L, pH 7.6±0.2, sterilized at 121°C for 30min.

[0041] LB liquid culture medium: NaCl 30g, yeast extract 5g, peptone 10g, H2O 1L, pH 7.4-7.5, sterilized at 121°C for 30min.

[0042] When the above culture medium is used to make solid culture medium, 16-20g / L of agar is additionally added.

[0043] S3. Separation and purification: 100 μL of the enriched bacterial solution was taken and added to a 1.5 mL centrifuge tube containing 900 μL of sterile water, mixed well, and 10 -1 -10 -7 different dilution gradients of the bacterial suspension. Then, 200 μL of the bacterial suspension at three dilution gradients of 10 -5 , 10 -6 , and 10 -7 were uniformly spread on MA solid medium with a glass triangle rod. The diluted and spread MA solid medium was cultured at 37°C on an inverted shaker until visible colonies were formed. Single colonies with different morphologies, sizes, and colors were selected from the medium with a loop. The selected colonies were streaked on new MA solid medium and cultured at 37°C on an inverted shaker. The streaking and separation were repeated multiple times until colonies with consistent morphology and no contamination were obtained. The purified single colonies were inoculated on LB slant solid medium and stored in a refrigerator at 4°C.

[0044] Example 2 Identification of Pseudomonas stutzeri SND-1 strain

[0045] The purified bacteria were used to extract the genomic DNA of the strain with TaKaRa MiniBEST Bacteria Genomic DNA Extraction Kit Ver.3.0. The universal primers 27F (5'- AGAGTTTGATCCTGGCTCAG-3', as shown in SEQ ID NO:2) and 1492R (5'-GGTTACCTTGTTACGACTT-3', as shown in SEQ ID NO:3) for 16S rDNA sequence were used as PCR reaction primers, and 2×TsingKE Master Mix system was used for PCR amplification. The PCR reaction system was: genomic DNA 1 μL, 2×TsingKE Master Mix 25 μL, 27F Primer (10 μM) 1 μL, 1492R Primer (10 μM) 1 μL, dH2O 22 μL. The PCR reaction conditions were: pre-denaturation at 94°C for 10 min, 30 cycles of 94°C for 30 s, 55°C for 30 s, 72°C for 1.5 min, and extension at 72°C for 10 min. The obtained PCR product was purified and sent to GenScript Biotech (Shanghai) Co., Ltd. for sequencing.

[0046] The 16S rDNA sequence of strain SND-1 (as shown in SEQ ID NO: 1) was uploaded to the NCBI database and subjected to BLAST homologous sequence alignment, the results showed that the similarity with Stutzerimonas stutzeri strain SM12 (MT356167.1) and Stutzerimonas stutzeri strain OsEnb_ALM_B7 (MN889324.1) were both higher than 100%, and the phylogenetic tree constructed by MEGA7 is as shown in Figure 1 The above analysis results, the strain was identified as Stutzerimonas stutzeri SND-1.

[0047]

[0048] Example 3 Growth curve of Pseudomonas stutzeri SND-1 strain

[0049] The pure strain SND-1 was inoculated into sterilized LB liquid medium and cultured at 37°C and 180 r / min for 24 h to prepare seed liquid. The seed liquid was inoculated into 100 ml of LB liquid medium at 2% and cultured at 37°C and 180 r / min for 48 h. The OD 600 was measured every hour to reflect the growth of the strain SND-1. 600 The growth curve was plotted with OD 600 as the vertical coordinate and the culture time as the horizontal coordinate.

[0050] The OD 600 of the bacterial suspension was measured at regular time intervals to reflect the growth of the strain SND-1. As shown in FIG. 1, the strain SND-1 was in the lag phase from 0 to 6 h, and the growth rate was slow. At 6 h, the strain SND-1 entered the logarithmic growth phase, and the growth rate was fast. The difference between the growth curves was large, and the growth of the strain SND-1 accelerated. After 18 h, the growth of the strain SND-1 decelerated, and the growth reached the maximum at 36 h, and the strain SND-1 entered the stable phase. Figure 2

[0051] Example 4 Denitrification rate of Pseudomonas stutzeri SND-1 strain at different time periods

[0052] The pure strain SND-1 was inoculated into sterilized LB liquid medium and cultured at 37°C and 180 r / min for 24 h to prepare seed liquid. The eel seawater aquaculture tail water was used as the background, and the strain SND-1 was inoculated into 1 L of the tail water at 1.5%, and 0.22 g of white sugar was added per liter of the tail water as a carbon source, and the pH was 7.6. The tail water was cultured at 37°C and 180 r / min, and samples were collected at 0, 2, 4, 6, 8, 10, 12, 16, 20 and 24 h, and centrifuged at 8000 r / min and 28°C. The concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen in the supernatant were measured. The results (the data are listed to the maximum removal rate, and the same below) are shown in Tables 1, 2, 3, 4 and 5.

[0053] As shown in Table 1, in the lag phase of bacterial growth, the ammonia nitrogen removal rate is low at the hydraulic retention time (HRT) of 0-6h, and the removal rate increases rapidly at the HRT of 6-12h, the ammonia nitrogen removal rates are 82.62% and 96.01% at the HRT of 10h and 12h respectively, and the ammonia nitrogen removal rate reaches the maximum of 97.02% at the HRT of 16h. The ammonia nitrogen removal rate of the Pseudomonas sp. MA-ZP17-13 disclosed in the patent CN201910882118.4 is only 88.8% at 72h, and the ammonia nitrogen removal rate of the Alcanivorax sp. DN-7 disclosed in the patent CN202110624074.2 is only more than 90% at 120h. The SND-1 strain of Pseudomonas stutzeri of the present application has higher ammonia nitrogen removal rate and shorter necessary HRT than the Pseudomonas sp. MA-ZP17-13 and the Alcanivorax sp. DN-7, which shows that the SND-1 strain of the present application has higher efficiency and faster ammonia nitrogen removal function as a heterotrophic ammonia oxidizing strain, and has great industrial application prospect.

[0054] As shown in Table 2, in the lag phase of bacterial growth, the nitrite nitrogen removal rate is low at the HRT of 0-2h, and the removal rate increases rapidly at the HRT of 2-10h, the nitrite nitrogen removal rates are 81.76% and 94.34% at the HRT of 10h and 12h respectively, and the nitrite nitrogen removal rate reaches the maximum of 97.48% at the HRT of 16h.

[0055] As shown in Table 3, in the lag phase of bacterial growth, the nitrate nitrogen removal rate is low at the HRT of 0-2h, and the removal rate increases rapidly at the HRT of 2-8h, the nitrate nitrogen removal rate is 67.72% at the HRT of 10h, and the nitrate nitrogen removal rate reaches the maximum of 71.92% at the HRT of 16h.

[0056] As shown in Table 4, in the lag phase of bacterial growth, the inorganic nitrogen removal rate is low at the HRT of 0-6h, and the removal rate increases rapidly at the HRT of 6-12h, the inorganic nitrogen removal rates are 79.74% and 90.47% at the HRT of 10h and 12h respectively, and the inorganic nitrogen removal rate reaches the maximum of 92.35% at the HRT of 16h.

[0057] As shown in Table 5, in the lag phase of bacterial growth, the total nitrogen removal rate is low at the HRT of 0-6h, and the removal rate increases rapidly at the HRT of 6-12h, the total nitrogen removal rate is 67.44% at the HRT of 12h, and the total nitrogen removal rate reaches the maximum of 69.97% at the HRT of 16h.

[0058] In summary, the SND-1 strain can be economically and effectively applied to tail water treatment with the necessary HRT range of 10-16h, has the advantages of shorter necessary HRT and high removal rate, and has good application prospect.

[0059] Table 1 Ammonia nitrogen removal rate of Pseudomonas stutzeri SND-1 strain at different time periods

[0060] Time (h) Ammonia nitrogen concentration (mg / L) of treatment group Ammonia nitrogen removal rate (%) 0 13.779±0.044 0 2 12.998±0.013 5.67 4 11.930±0.019 13.42 6 10.712±0.015 22.26 8 7.147±0.018 48.13 10 2.395±0.013 82.62 12 0.550±0.002 96.01 16 0.411±0.010 97.02

[0061] Table 2 Nitrite nitrogen degradation rate of Pseudomonas stutzeri SND-1 strain at different time periods

[0062]

[0063]

[0064] Table 3 Nitrate nitrogen degradation rate of Pseudomonas stutzeri SND-1 strain at different time periods

[0065] Time (h) Nitrate nitrogen concentration (mg / L) of treatment group Nitrate nitrogen removal rate (%) 0 4.026±0.063 0 2 3.574±0.090 11.23 4 2.572±0.034 36.12 6 2.321±0.073 42.36 8 1.309±0.007 67.48 10 1.300±0.017 67.72 12 1.292±0.014 67.92 16 1.156±0.097 71.92

[0066] Table 4 Inorganic nitrogen removal rate of Pseudomonas stutzeri SND-1 strain at different time periods

[0067] Time (h) Inorganic nitrogen concentration (mg / L) of treatment group Inorganic nitrogen removal rate (%) 0 21.739±0.132 0 2 20.370±0.076 6.30 4 17.913±0.047 17.60 6 16.112±0.169 25.88 8 10.518±0.021 51.62 10 4.404±0.024 79.74 12 2.072±0.013 90.47 16 1.663±0.103 92.35

[0068] Table 5 Total nitrogen removal rate of Pseudomonas stutzeri SND-1 strain at different time periods

[0069] Time (h) Total nitrogen concentration (mg / L) of treatment group Total nitrogen removal rate (%) 0 39.981±0.121 0 2 39.009±0.096 2.43 4 35.107±0.087 12.19 6 29.854±0.091 25.33 8 27.423±0.147 31.41 10 23.741±0.108 40.62 12 13.018±0.093 67.44 16 12.006±0.110 69.97

[0070] Example 5 Determination of nitrogen removal effect of Pseudomonas stutzeri SND-1 strain on aquaculture water quality under different carbon sources

[0071] The pure strain SND-1 was inoculated in sterilized LB liquid medium, and seed liquid was prepared by culturing at 37°C and 180r / min for 24h. The eel seawater aquaculture tail water was used as the background, and the strain SND-1 was inoculated in 1L tail water at an inoculation amount of 2%, 0.22g of different carbon sources was added per liter of tail water, and the pH was 7.6. Six treatment groups of different carbon sources were set: brown sugar, white sugar, sodium acetate, sodium succinate, maltose, and glucose. After 16h of culture in a constant temperature shaker at 37°C and 180r / min, the sample was collected, high-speed centrifugation was carried out at 28°C and 8000r / min, and the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and total nitrogen in the supernatant were measured. The determination results are shown in Tables 6, 7, 8, 9, and 10.

[0072] The denitrification effect of strain SND-1 was different under different carbon sources. Under the conditions of background ammonia nitrogen concentration of 6.079±0.025 mg / L, nitrite nitrogen concentration of 1.305±0.035 mg / L, nitrate nitrogen concentration of 2.405±0.032 mg / L and total nitrogen concentration of 25.141±0.160 mg / L, the removal rates of inorganic nitrogen and total nitrogen were higher when the carbon source was red sugar and sodium acetate. When sodium succinate was used as the sole carbon source, the removal rates of inorganic nitrogen and total nitrogen reached the highest value of 91.34% and 62.71% at HRT of 16 h. When white sugar was used as the carbon source, the removal rates of inorganic nitrogen and total nitrogen were 89.27% and 61.48% at HRT of 16 h, which had no significant difference (P>0.05) with the denitrification effect of the sodium succinate group. Considering the cost, white sugar was suitable as the carbon source for strain SND-1 denitrification.

[0073] Table 6 Determination of the degradation effect of Pseudomonas stutzeri SND-1 strain on ammonia nitrogen in aquaculture water under different carbon sources

[0074] Carbon source Ammonia nitrogen concentration (mg / L) of treatment group Ammonia nitrogen removal rate (%) Maltose 1.205±0.030 80.17 Glucose 1.082±0.088 82.20 Brown sugar 0.479±0.021 92.12 Sodium acetate 0.427±0.018 92.97 White sugar 0.376±0.037 93.82 Sodium succinate 0.238±0.019 96.09

[0075] Table 7 Determination of the degradation effect of Pseudomonas stutzeri SND-1 strain on nitrite nitrogen in aquaculture water under different carbon sources

[0076] Carbon source Nitrite nitrogen concentration (mg / L) of treatment group Nitrite nitrogen removal rate (%) Maltose 0.292±0.020 77.6 Glucose 0.267±0.010 79.54 Brown sugar 0.389±0.028 70.24 Sodium acetate 0.192±0.010 85.33 White sugar 0.148±0.007 88.64 Sodium succinate 0.119±0.019 90.88

[0077] Table 8 Determination of the degradation effect of Pseudomonas stutzeri SND-1 strain on nitrate nitrogen in aquaculture water under different carbon sources

[0078] Carbon source Nitrate nitrogen concentration (mg / L) of treatment group Nitrate nitrogen removal rate (%) Maltose 1.071±0.033 55.49 Glucose 1.013±0.039 57.88 Brown sugar 0.714±0.025 70.33 Sodium acetate 0.585±0.013 75.66 White sugar 0.560±0.003 76.74 Sodium succinate 0.492±0.018 79.56

[0079] Table 9 Determination of the degradation effect of Pseudomonas stutzeri SND-1 strain on inorganic nitrogen in aquaculture water under different carbon sources

[0080] Carbon source Inorganic nitrogen concentration (mg / L) of treatment group Inorganic nitrogen removal rate (%) Maltose 2.568±0.081 75.03 Glucose 2.514±0.119 74.46 Brown sugar 1.581±0.018 83.68 Sodium acetate 1.204±0.032 87.65 White sugar 1.083±0.045 89.27 Sodium succinate 0.848±0.005 91.31

[0081] Table 10 Determination of the degradation effect of Pseudomonas stutzeri SND-1 strain on total nitrogen in aquaculture water under different carbon sources

[0082] Carbon source Total nitrogen concentration (mg / L) of treatment group Total nitrogen removal rate (%) Maltose 12.460±0.091 50.44 Glucose 12.261±0.092 51.23 Brown sugar 9.989±0.089 60.27 Sodium acetate 9.926±0.073 60.52 White sugar 9.684±0.095 61.48 Sodium succinate 9.375±0.063 62.71

[0083] Example 6 Determination of the denitrification effect of Pseudomonas stutzeri SND-1 strain on aquaculture water under different C / N

[0084] The pure strain SND-1 was inoculated into sterilized LB liquid medium, and cultured at 37°C and 180 r / min for 24 h to prepare a seed liquid. The eel aquaculture tail water was used as a background, and the strain SND-1 was inoculated into 1 L of the tail water at a inoculation amount of 2%, and the pH was 7.6. Sugar was used as a carbon source to set up three treatment groups with different C / N: 4, 6 and 8. After being cultured in a constant-temperature shaker at 37°C and 180 r / min for 16 h, samples were collected, and the supernatant was measured for the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen at a high speed of 28°C and 8000 r / min. The measurement results are shown in Tables 11, 12, 13, 14 and 15.

[0085] The denitrification effect of the strain SND-1 was different under different C / N. Under the conditions of a background ammonia nitrogen concentration of 5.365±0.044 mg / L, a nitrite nitrogen concentration of 1.880±0.023 mg / L, a nitrate nitrogen concentration of 2.579±0.016 mg / L and a total nitrogen concentration of 24.911±0.079 mg / L, the denitrification effect of the strain SND-1 was improved with the increase of C / N in the range of C / N 4-6. When C / N was 6, the removal rates of inorganic nitrogen and total nitrogen reached the highest of 76.44% and 58.96% respectively under HRT 16 h. Therefore, the strain SND-1 belongs to a heterotrophic functional strain, and C / N 6 is the most suitable application condition for the denitrification effect of the strain SND-1.

[0086] Table 11 Measurement of the ammonia nitrogen degradation effect of the Pseudomonas stutzeri SND-1 strain under different C / N in aquaculture water quality

[0087] C / N Ammonia nitrogen concentration (mg / L) of treatment group Ammonia nitrogen removal rate (%) 4 1.974±0.051 63.21 6 1.087±0.014 79.74

[0088] Table 12 Measurement of the nitrite nitrogen degradation effect of the Pseudomonas stutzeri SND-1 strain under different C / N in aquaculture water quality

[0089] C / N Nitrite nitrogen concentration (mg / L) of treatment group Nitrite nitrogen removal rate (%) 4 0.278±0.004 85.23 6 0.705±0.020 62.50

[0090] Table 13 Measurement of the nitrate nitrogen degradation effect of the Pseudomonas stutzeri SND-1 strain under different C / N in aquaculture water quality

[0091] C / N Nitrate nitrogen concentration (mg / L) of treatment group Nitrate nitrogen removal rate (%) 4 0.598±0.026 76.82 6 0.523±0.010 79.72

[0092] Table 14 Measurement of the inorganic nitrogen degradation effect of the Pseudomonas stutzeri SND-1 strain under different C / N in aquaculture water quality

[0093] C / N Inorganic nitrogen concentration (mg / L) of treatment group Inorganic nitrogen removal rate (%) 4 2.849±0.059 71.00 6 2.315±0.025 76.44

[0094] Table 15 Measurement of the total nitrogen degradation effect of the Pseudomonas stutzeri SND-1 strain under different C / N in aquaculture water quality

[0095] C / N Total nitrogen concentration (mg / L) of treatment group Total nitrogen removal rate (%) 4 11.090±0.166 55.48 6 10.223±0.098 58.96

[0096] Example 7 Determination of the effect of Pseudomonas stutzeri SND-1 strain on nitrogen removal in aquaculture water at different addition amounts

[0097] The pure strain SND-1 was inoculated into sterilized LB liquid medium and cultured at 37°C and 180 r / min for 24 h to prepare seed liquid. The eel seawater aquaculture tail water was used as the background, and the strain SND-1 was inoculated into 1 L of tail water at different inoculation amounts, with white sugar as the carbon source, and the C / N was adjusted to 6, and the pH was 7.6. Three treatment groups with different addition amounts were set: 1%, 1.5%, and 2%, and after 16 h of culture in a 37°C constant temperature shaker at 180 r / min, the samples were collected, centrifuged at 28°C and 8000 r / min, and the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and total nitrogen in the supernatant were measured. The results are shown in Tables 16, 17, 18, 19, and 20.

[0098] The nitrogen removal effects of the strain SND-1 at different addition amounts were different. Under the conditions of a background ammonia nitrogen concentration of 6.401 ± 0.010 mg / L, a nitrite nitrogen concentration of 2.868 ± 0.026 mg / L, a nitrate nitrogen concentration of 4.366 ± 0.004 mg / L, and a total nitrogen concentration of 34.123 ± 0.092 mg / L, the removal rates of inorganic nitrogen and total nitrogen reached the highest of 75.16% and 60.15% at an addition amount of 1.5% and an HRT of 16 h, and the addition amount of 1.5% was the most suitable application condition for the nitrogen removal effect of the strain SND-1.

[0099] Table 16 Effect of Pseudomonas stutzeri SND-1 strain on ammonia nitrogen degradation in aquaculture water at different addition amounts

[0100] Addition amount (%) Ammonia nitrogen concentration (mg / L) of treatment group Ammonia nitrogen removal rate (%) 1％ 4.002±0.040 37.48 1.5％ 1.679±0.086 73.77 2.0％ 3.136±0.080 51.01

[0101] Table 17 Effect of Pseudomonas stutzeri SND-1 strain on nitrite nitrogen degradation in aquaculture water at different addition amounts

[0102] Addition amount (%) Nitrite nitrogen concentration (mg / L) of treatment group Nitrite nitrogen removal rate (%) 1％ 1.908±0.023 33.48 1.5％ 0.331±0.032 88.46

[0103] Table 18 Effect of Pseudomonas stutzeri SND-1 strain on nitrate nitrogen degradation in aquaculture water at different addition amounts

[0104] Addition amount (%) Nitrate nitrogen concentration (mg / L) of treatment group Nitrate nitrogen removal rate (%) 1％ 3.341±0.025 23.48 1.5％ 1.377±0.028 68.46

[0105] Table 19 Effect of Pseudomonas stutzeri SND-1 strain on inorganic nitrogen degradation in aquaculture water at different addition amounts

[0106] Addition amount (%) Inorganic nitrogen concentration (mg / L) of treatment group Inorganic nitrogen removal rate (%) 1％ 9.250±0.035 32.16 1.5％ 3.387±0.133 75.16

[0107] Table 20 Determination of the effect of Pseudomonas stutzeri SND-1 strain on the degradation of total nitrogen in aquaculture water at different addition amounts

[0108] Addition amount (%) Total nitrogen concentration (mg / L) of treatment group Total nitrogen removal rate (%) 1％ 26.527±0.176 22.26 1.5％ 13.598±0.061 60.15

[0109] Example 8 Determination of the effect of Pseudomonas stutzeri SND-1 strain on the nitrogen removal in aquaculture water at different salinities

[0110] The pure strain SND-1 was inoculated into sterilized LB liquid medium and cultured at 37°C and 180 r / min for 24 h to prepare seed liquid. The tail water of eel mariculture was used as the background, and the strain SND-1 was inoculated into 1 L of tail water at an inoculation amount of 1.5%, with white sugar as the carbon source, the C / N was adjusted to 6, and the pH was 7.6. Eleven treatment groups with different salinities were set: 0, 2, 4, 6, 8, 10, 15, 20, 25, 30, and 35. After 16 h of culture in a constant temperature shaker at 37°C and 180 r / min, the samples were collected and centrifuged at 8000 r / min and 28°C. The concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and total nitrogen in the supernatant were measured, and the results are shown in Tables 21, 22, 23, 24, and 25.

[0111] The nitrogen removal effect of the strain SND-1 was different at different salinities. Under the conditions of a background ammonia nitrogen concentration of 6.469 ± 0.032 mg / L, a nitrite nitrogen concentration of 3.369 ± 0.002 mg / L, a nitrate nitrogen concentration of 3.389 ± 0.029 mg / L, and a total nitrogen concentration of 36.087 ± 0.132 mg / L, the nitrogen removal effect of the strain SND-1 increased with increasing salinity in the range of 0-15. At a salinity of 15, the removal rates of inorganic nitrogen and total nitrogen were the highest, reaching 92.99% and 64.09%, respectively, at an HRT of 16 h. In the range of 6-25, the removal rates of inorganic nitrogen were all higher than 60%, and the total nitrogen removal rates were all higher than 30% at an HRT of 16 h. Notably, at a salinity of 25, the removal rates of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen were still 87.35%, 94.31%, and 85.34%, respectively, at an HRT of 16 h. Therefore, the strain SND-1 is a broad-salinity functional strain that can function in the range of 0-35, and the suitable salinity range is 0-25. A salinity of 15 is the most suitable application condition for the strain SND-1 to remove nitrogen.

[0112] Table 21 Effect of Pseudomonas stutzeri SND-1 strain on the degradation of ammonia nitrogen in aquaculture water at different salinities

[0113] Salinity Ammonia nitrogen concentration (mg / L) of treatment group Ammonia nitrogen removal rate (%) 0 5.202±0.024 19.58 2 4.490±0.027 20.59 4 3.709±0.015 22.67 6 3.530±0.009 25.43 8 3.220±0.020 50.22 10 1.531±0.034 76.34 15 0.239±0.018 96.31 20 0.827±0.026 87.21 25 0.818±0.017 87.35

[0114] Table 22 Effect of Pseudomonas stutzeri SND-1 strain on the degradation of nitrite nitrogen in aquaculture water at different salinities

[0115] Salinity Nitrite nitrogen concentration (mg / L) of treatment group Nitrite nitrogen removal rate (%) 0 0.031±0.020 99.08 2 0.040±0.035 98.81 4 0.019±0.013 99.44 6 0.049±0.009 98.55 8 0.044±0.036 98.69 10 0.052±0.031 98.46 15 0.192±0.010 94.31 20 0.415±0.013 87.69 25 0.931±0.005 72.36

[0116] Table 23 Nitrate nitrogen degradation effect of Pseudomonas stutzeri SND-1 strain on aquaculture water quality at different salinities

[0117]

[0118]

[0119] Table 24 Inorganic nitrogen degradation effect of Pseudomonas stutzeri SND-1 strain on aquaculture water quality at different salinities

[0120] Salinity Inorganic nitrogen concentration (mg / L) of treatment group Inorganic nitrogen removal rate (%) 0 8.472±0.065 35.95 2 6.761±0.034 48.88 4 5.971±0.033 54.86 6 5.069±0.017 61.68 8 4.581±0.033 65.37 10 2.124±0.027 83.94 15 0.927±0.026 92.99 20 3.268±0.061 75.29 25 3.703±0.032 72.00 30 9.28±0.03 29.87 35 11.28±0.03 14.75

[0121] Table 25 Total nitrogen degradation effect of Pseudomonas stutzeri SND-1 strain on aquaculture water quality at different salinities

[0122]

[0123]

[0124] Example 9 Determination of nitrogen removal effect of Pseudomonas stutzeri SND-1 strain on aquaculture water quality at different water temperatures

[0125] The pure strain SND-1 was inoculated in sterilized LB liquid medium, and cultured at 37°C and 180 r / min for 24 h to prepare seed liquid. The eel seawater aquaculture tail water was used as the background, the salinity was adjusted to 15, the strain SND-1 was inoculated in 1 L of tail water at an inoculation amount of 1.5%, white sugar was used as the carbon source, the C / N was adjusted to 6, the pH was 7.6, seven treatment groups with different water temperatures were set: 25°C, 28°C, 30°C, 33°C, 35°C, 37°C and 40°C, and after 16 h of culture in a constant temperature shaker at 180 r / min, the sample was collected, high-speed centrifugation was carried out at 28°C and 8000 r / min, the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen in the supernatant were measured, and the determination results are shown in Tables 26, 27, 28, 29 and 30.

[0126] The denitrification effect of strain SND-1 was different at different water temperatures. Under the conditions of background ammonia nitrogen concentration of 9.130±0.015 mg / L, nitrite nitrogen concentration of 1.876±0.017 mg / L, nitrate nitrogen concentration of 5.877±0.071 mg / L and total nitrogen concentration of 30.009±0.120 mg / L, the removal rates of inorganic nitrogen and total nitrogen reached the highest of 78.34% and 57.27% at water temperature of 37℃ and HRT of 16h, and the removal rates of inorganic nitrogen and total nitrogen decreased to 57.96% and 29.18% at water temperature of 40℃ and HRT of 16h. Within the range of water temperature of 28-37℃, the removal rate of inorganic nitrogen was more than 60% and the removal rate of total nitrogen was more than 40% at HRT of 16h, so the suitable water temperature range of strain SND-1 was 28-37℃, and the water temperature of 37℃ was the most suitable application condition for the denitrification effect of strain SND-1.

[0127] Table 26 Ammonia nitrogen degradation effect of Pseudomonas stutzeri SND-1 strain at different water temperatures in aquaculture tail water

[0128]

[0129]

[0130] Table 27 Nitrite nitrogen degradation effect of Pseudomonas stutzeri SND-1 strain at different water temperatures in aquaculture tail water

[0131] Water temperature (℃) Nitrite nitrogen concentration (mg / L) of treatment group Nitrite nitrogen removal rate (%) 25 0.579±0.025 69.12 28 0.332±0.005 82.32 30 0.572±0.024 69.49 33 0.418±0.026 77.71 35 0.536±0.015 71.45 37 0.198±0.030 89.46

[0132] Table 28 Nitrate nitrogen degradation effect of Pseudomonas stutzeri SND-1 strain at different water temperatures in aquaculture tail water

[0133] Water temperature (℃) Nitrate nitrogen concentration (mg / L) of treatment group Nitrate nitrogen removal rate (%) 25 1.463±0.026 49.12 28 1.087±0.032 62.19 30 1.165±0.012 59.49 33 1.216±0.008 57.71 35 1.396±0.028 51.45 37 0.863±0.035 69.99

[0134] Table 29 Inorganic nitrogen degradation effect of Pseudomonas stutzeri SND-1 strain at different water temperatures in aquaculture tail water

[0135]

[0136]

[0137] Table 30 Total nitrogen degradation effect of Pseudomonas stutzeri SND-1 strain at different water temperatures in aquaculture tail water

[0138] Water temperature (℃) Total nitrogen concentration (mg / L) of treatment group Total nitrogen removal rate (%) 25 21.318±0.112 28.96 28 16.436±0.072 45.23 30 17.651±0.092 41.18 33 17.978±0.079 40.09 35 17.549±0.073 41.52 37 12.823±0.082 57.27

[0139] Example 10 Denitrification effect of Pseudomonas stutzeri SND-1 strain at different pH on aquaculture water quality

[0140] The pure strain SND-1 was inoculated in sterilized LB liquid medium, and cultured at 37℃ and 180r / min for 24h to prepare seed liquid. The eel aquaculture tail water was used as the background, and the strain SND-1 was inoculated in 1L tail water at an inoculation amount of 1.5%, the salinity was adjusted to 15, white sugar was used as the carbon source, the C / N was adjusted to 6, five different pH treatment groups were set: 6, 6.5, 7, 8, and 8.5, and after 16h of culture in a 37℃ constant temperature shaker at 180r / min, the sample was collected, and the supernatant was measured for ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen concentration under the condition of 28℃ and 8000r / min high-speed centrifugation. The determination results are shown in Tables 31, 32, 33, 34 and 35.

[0141] The denitrification effect of the strain SND-1 is different at different pH. Under the conditions of background ammonia nitrogen concentration of 8.570±0.119mg / L, nitrite nitrogen concentration of 1.985±0.014mg / L, nitrate nitrogen concentration of 4.985±0.034mg / L and total nitrogen concentration of 28.912±0.117mg / L, when pH is 8, the removal rates of inorganic nitrogen and total nitrogen reach the highest of 71.83% and 64.27% at HRT of 16h, and when pH is 8.5, the removal rates of inorganic nitrogen and total nitrogen decrease to 71.58% and 45.08% at HRT of 16h, so pH 8 is the most suitable application condition for the denitrification effect of the strain SND-1.

[0142] Table 31 Determing the degradation effect of Pseudomonas stutzeri SND-1 strain on ammonia nitrogen in aquaculture water at different pH

[0143]

[0144]

[0145] Table 32 Determing the degradation effect of Pseudomonas stutzeri SND-1 strain on nitrite nitrogen in aquaculture water at different pH

[0146] pH Nitrite nitrogen concentration (mg / L) of treatment group Nitrite nitrogen removal rate (%) 6 0.584±0.027 70.58 6.5 0.597±0.018 69.90 7 0.766±0.010 61.43 8 0.349±0.008 82.41 8.5 0.508±0.039 74.43

[0147] Table 33 Determing the degradation effect of Pseudomonas stutzeri SND-1 strain on nitrate nitrogen in aquaculture water at different pH

[0148] pH Nitrate nitrogen concentration (mg / L) of treatment group Nitrate nitrogen removal rate (%) 6 1.394±0.019 53.31 6.5 1.495±0.016 49.9 7 1.753±0.017 41.27 8 1.122±0.033 62.41 8.5 1.214±0.037 59.33

[0149] Table 34 Determing the degradation effect of Pseudomonas stutzeri SND-1 strain on inorganic nitrogen in aquaculture water at different pH

[0150] pH Inorganic nitrogen concentration (mg / L) of treatment group Inorganic nitrogen removal rate (%) 6 6.977±0.064 48.47 6.5 7.460±0.036 44.91 7 5.590±0.012 58.72 8 3.814±0.018 71.83 8.5 3.848±0.029 71.58

[0151] Table 35 Determination of degradation effect of Pseudomonas stutzeri SND-1 strain on total nitrogen in aquaculture water at different pH

[0152]

[0153]

[0154] Example 11 Determination of nitrogen removal effect of Pseudomonas stutzeri SND-1 strain on aquaculture water at different dissolved oxygen

[0155] The pure strain SND-1 was inoculated into sterilized LB liquid medium, and cultured at 37°C and 180 r / min for 24 h to prepare seed liquid. The eel seawater aquaculture tail water was used as the background, the salinity was adjusted to 15, the strain SND-1 was inoculated into 1 L of tail water at an inoculation amount of 1.5%, white sugar was used as the carbon source, the C / N was adjusted to 6, the pH was 8, and 7 different dissolved oxygen treatment groups were set: 4, 6, 7, 8, 8.5, 9 mg / L. After 16 h, sampling was performed under the condition of high-speed centrifugation at 28°C and 8000 r / min, and the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen in the supernatant were measured. The determination results are shown in Tables 36, 37, 38, 39 and 40.

[0156] The nitrogen removal effect of the strain SND-1 was different under different dissolved oxygen. Under the conditions of an ammonia nitrogen concentration of 7.055±0.020 mg / L, a nitrite nitrogen concentration of 1.898±0.010 mg / L, a nitrate nitrogen concentration of 2.868±0.030 mg / L and a total nitrogen concentration of 28.912±0.117 mg / L, within the range of dissolved oxygen of 4-8.5 mg / L, the nitrogen removal effect of the strain SND-1 was improved with the increase of dissolved oxygen. When the dissolved oxygen was 8.5 mg / L, the inorganic nitrogen and total nitrogen removal rates reached the highest of 91.21% and 59.27% respectively under the HRT of 16 h. Therefore, the strain SND-1 is an aerobic microorganism, and the dissolved oxygen of 8.5 mg / L is the most suitable application condition for the nitrogen removal effect of the strain SND-1.

[0157] Table 36 Determination of degradation effect of Pseudomonas stutzeri SND-1 strain on ammonia nitrogen in aquaculture water at different dissolved oxygen

[0158] Dissolved oxygen (mg / L) Ammonia nitrogen concentration (mg / L) of treatment group Ammonia nitrogen removal rate (%) 4 2.852±0.004 59.57 6 2.030±0.022 71.22 7 0.702±0.025 90.05 8 0.447±0.018 93.66 8.5 0.399±0.010 94.34 9 0.667±0.020 90.55

[0159] Table 37 Determination of degradation effect of Pseudomonas stutzeri SND-1 strain on nitrite nitrogen in aquaculture water at different pH

[0160] Dissolved oxygen (mg / L) Nitrite nitrogen concentration (mg / L) of treatment group Nitrite nitrogen removal rate (%) 4 0.974±0.009 48.678 6 0.672±0.027 64.587 7 0.386±0.027 79.668 8 0.234±0.016 87.69 8.5 0.179±0.003 90.55 9 0.217±0.033 88.57

[0161] Table 38 Determination of degradation effect of Pseudomonas stutzeri SND-1 strain on nitrate nitrogen in aquaculture water at different dissolved oxygen

[0162] Dissolved oxygen (mg / L) Nitrate nitrogen concentration (mg / L) of treatment group Nitrate nitrogen removal rate (%) 4 2.029±0.011 29.46 6 1.042±0.016 64.13 7 0.582±0.043 80.25 8 0.548±0.013 81.46 8.5 0.460±0.024 84.55 9 0.499±0.027 83.17

[0163] Table 39 Determination of degradation effect of Pseudomonas stutzeri SND-1 strain on inorganic nitrogen in aquaculture water under different dissolved oxygen

[0164] Dissolved oxygen (mg / L) Inorganic nitrogen concentration (mg / L) of treatment group Inorganic nitrogen removal rate (%) 4 5.855±0.015 50.47 6 3.744±0.057 68.33 7 1.670±0.054 85.87 8 1.229±0.021 89.60 8.5 1.039±0.024 91.21 9 1.383±0.014 88.30

[0165] Table 40 Determination of degradation effect of Pseudomonas stutzeri SND-1 strain on total nitrogen in aquaculture water under different dissolved oxygen

[0166]

[0167]

[0168] Example 12 Safety detection of Pseudomonas stutzeri SND-1 strain in aquaculture application

[0169] The Pseudomonas stutzeri SND-1 was inoculated into sterilized LB liquid medium, and was amplified and cultured in a constant temperature shaker at 37°C and 180 r / min for 24 h to prepare a seed solution. The seed solution was added into a biological filter for treating aquaculture wastewater of a recirculating water Australian eel culture system at an inoculation amount of 5.5 x 10 4 The recirculating water Australian eel culture system was normally fed with feed and managed, and the average water circulation frequency was 9 times per day, and the culture lasted for 15 days.

[0170] During the recirculating water Australian eel culture, the Australian eels grew healthily without disease and death. The results show that the Pseudomonas stutzeri SND-1 strain has stable safety in the nitrogen removal process of Australian eel culture. According to related research, the biological hazard degree of Pseudomonas stutzeri is four categories, and there is no pathogenic object.

[0171] In summary, the Pseudomonas stutzeri SND-1 strain can degrade the ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen concentration in the aquaculture water under an aerobic environment, has no toxic effect on aquatic animals, has the advantages of wide application conditions, good degradation effect, high efficiency and no secondary pollution, and can be applied to degrade the ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and total nitrogen concentration in the water body in a freshwater or seawater culture environment. Compared with the prior art, the ammonia nitrogen removal rate of the Pseudomonas stutzeri SND-1 strain of the present application is obviously higher than that of other patent strains, and the hydraulic retention time is shorter. The Pseudomonas stutzeri SND-1 strain has a wide salt tolerance, and has a remarkable application effect in freshwater and seawater environments. At the same time, it is isolated from the culture environment of aquatic economic animals, has no toxic effect on aquatic animals when applied in the culture water, and can be widely applied to the water environment scene of aquaculture and fishery.

[0172] While the foregoing description has described specific embodiments of the application, one ordinary skill in the art will appreciate that various modifications and changes can be made thereto without departing from the spirit and scope of the application, as set forth in the appended claims.

Claims

1. A strain of *Pseudomonas stearothermii* SND-1, characterized in that: The *Pseudomonas schlegelii* strain SND-1 was deposited at the China Center for Type Culture Collection on October 15, 2024, with accession number CCTCC NO: M 20242216.

2. The culture of Pseudomonas schlegelii SND-1 strain as described in claim 1.

3. The application of the culture of *Pseudomonas schlegelii* SND-1 strain as described in claim 1 or the culture of *Pseudomonas schlegelii* SND-1 strain as described in claim 2 in the preparation of bacterial agents.

4. The application according to claim 3, characterized in that: The application is to reduce the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and total nitrogen in water bodies under euryhaline conditions.

5. The application of the *Pseudomonas schlegelii* SND-1 strain as described in claim 1 or the culture of the *Pseudomonas schlegelii* SND-1 strain as described in claim 2 in the preparation of microecological preparations.

6. The application according to claim 5, characterized in that: The application is to reduce the concentrations of ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and total nitrogen in water bodies under euryhaline conditions.

7. A microbial agent, characterized in that, The bacterial agent comprises the strain of *Pseudomonas schlegelii* SND-1 as described in claim 1 or a culture of the strain of *Pseudomonas schlegelii* SND-1 as described in claim 2.

8. A microecological preparation, characterized in that, The microecological preparation includes the *Pseudomonas schlegelii* SND-1 strain as described in claim 1 or a culture of the *Pseudomonas schlegelii* SND-1 strain as described in claim 2.

9. The method for culturing the *Pseudomonas schlegelii* SND-1 strain according to claim 1, characterized in that: The *Pseudomonas schlegelii* SND-1 strain was placed in LB liquid medium and cultured continuously for 18–36 h at 28–37 °C and 180 r / min.

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