Antibiotic-resistant marine heterotrophic ammonia assimilation-aerobic denitrification bacterium and application thereof

Abstract

The invention discloses an antibiotic-resistant marine heterotrophic ammonia assimilation-aerobic denitrification bacterium and application thereof, and belongs to the field of aquaculture water treatment. The invention relates to marine antibiotic-resistant efficient marine denitrifier LAN01, which can take polyhydroxyalkanoate as a unique carbon source, can realize the functions of heterotrophic ammonia assimilation and aerobic denitrification under the stress of sulfamethoxazole antibiotics with different concentrations, and can synchronously convert phosphate. The strain has multiple resistances of high salinity, high alkalinity, antibiotics and the like, and can be used in the directions of mariculture tail water treatment, seawater circulating aquaculture water treatment, high-salt sewage treatment, saline-alkali soil bioremediation and the like so as to realize synchronous recovery of nutrient elements such as nitrogen and phosphorus in a mariculture environment.

Description

Technical Field

[0001] The present invention belongs to the technical fields of aquaculture water treatment and ecological environment governance and restoration, and specifically relates to a marine heterotrophic ammonia assimilation-aerobic denitrifying bacterium resistant to antibiotics and its application. Background Art

[0002] Intensive seawater aquaculture tail water usually contains high concentrations of inorganic nitrogen and phosphate, and is affected by the use of antibiotics during the aquaculture process. While causing seawater eutrophication, it promotes the widespread dissemination of antibiotics and resistance genes. Sulfonamide antibiotics represented by sulfamethoxazole (SMX), as the main antibiotics used in seawater aquaculture, have high water solubility and low octanol-water partition coefficient, so they are more likely to remain in the aquaculture water for a long time and pose continuous ecological risks. The biofloc technology has been proven to be able to remove ammonia nitrogen and phosphate simultaneously under heterotrophic conditions. The biofloc technology is mainly used for in-situ aquaculture or as a component of a recirculating aquaculture system, and the carbon-nitrogen ratio in water is adjusted by inputting a carbon source to promote heterotrophic bacteria to rapidly assimilate ammonia nitrogen in water into bacterial protein. Ammonia assimilation does not involve complex nitrification-denitrification processes, and can directly assimilate ammonia nitrogen and phosphate produced by fish into bioflocs, thus realizing the synchronous recovery of nutrients such as nitrogen and phosphorus, and avoiding the large emission of greenhouse gases (N2O) during the nitrification and denitrification processes. It is a low-carbon and environmentally friendly nitrogen recovery technology.

[0003] However, ammonia-assimilating bacteria are generally sensitive to most antibiotics, resulting in problems such as poor shock resistance and low microbial activity during the actual application of seawater aquaculture water treatment, thus reducing the nitrogen and phosphorus removal efficiency of the system. The salt-tolerant and antibiotic-resistant heterotrophic ammonia-assimilating bacteria screened in this patent have good shock load capacity against antibiotic water quality, can play a good ammonia assimilation role under different seawater aquaculture water quality conditions, and simultaneously remove phosphate in water, providing a new solution for seawater aquaculture water treatment. Summary of the Invention

[0004] One aspect of the present invention is to provide a marine heterotrophic ammonia assimilation-aerobic denitrifying bacterium (Marinobacter nitratireducens) LAN01 resistant to antibiotics, which was deposited on November 08, 2024 at the China General Microbiological Culture Collection Center (CGMCC), with the deposit name being LAN01 and the deposit number being: CGMCC No. 32548. The deposit address is: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, China, Postcode: 100101.

[0005] The second aspect of the present invention provides a biological characteristic of the said bacterium (Marinobacter nitratireducens) LAN01 as follows:

[0006] (1) After culturing on nutrient agar medium at 30 °C for 48 - 72 h, smooth, moist, opaque, round, milky white colonies are formed, with a colony diameter of 1 - 2 mm;

[0007] (2) The cells of Marinobacter nitratireducens LAN01 are Gram-negative, rod-shaped, 0.3 - 0.5 μm wide × 1.0 - 2.0 μm long ( Figure 2 );

[0008] (2) It can grow on a liquid medium with one or several of NH4Cl, NaNO2, and KNO3 as the nitrogen source;

[0009] (3) The growth temperature required for Marinobacter nitratireducens LAN01 is 15 - 40 °C, the optimum growth temperature is 30 °C, the required salinity for growth is 2 - 4%, the required pH for growth is 7.5 - 9.5, the dissolved oxygen is 1 - 6 mg / L, and the rotation speed is 180 - 200 r / min;

[0010] (4) 16S rRNA gene sequence

[0011] The whole genome of Marinobacter nitratireducens LAN01 was sequenced, and its 16S rRNA gene sequence was intercepted for BLAST alignment. The results showed that the 16S rRNA gene sequence of Marinobacter nitratireducens LAN01 had a high similarity with Marinobacter nitratireducens strain AK21, as Figure 1 shown. However, previous reports on Marinobacter nitratireducens, including Marinobacter nitratireducens strain AK21, only reported its nitrate reduction ability, and none of them reported its abilities of antibiotic-resistant heterotrophic ammonia assimilation, phosphorus removal, and potential antibiotic degradation. Therefore, it can be determined that this Marinobacter nitratireducens LAN01 belongs to a novel strain in the species of Marinobacter nitratireducens.

[0012] The third aspect of the present invention is to provide a screening method for the antibiotic-resistant and highly efficient seawater nitrogen and phosphorus removal strain, and the screening method includes the following steps:

[0013] a) Isolation of strains: Take the bioflocs in the biofilter with polyhydroxyalkanoate (PHA) as the solid carbon source, and after interception through a 200-mesh filter, use sterile seawater to prepare a bacterial suspension and transfer it to a bacterial selection medium (with SMX) for screening until the ammonia nitrogen degradation rate exceeds 80% within 24 hours. Continue acclimatization and culture for 2 cycles (each cycle corresponds to 24 hours of culture in the bacterial selection medium), and then purify the strain;

[0014] b) Strain purification: Take 1 mL of the culture solution of the screened and domesticated bacteria (OD 600 =0.4), diluted with sterile PBS solution, for example, 10 3 -10 6 times, and then streak culture on a solid culture medium at a constant temperature of 30°C. After 48 to 72 hours, a single colony is picked after colonies grow on the culture medium; the picked single colony is purified 2 to 3 times, wherein the purification is performed by performing the bacterial selection culture medium acclimation in step a and the solid culture medium culture in step b;

[0015] c) inoculating the strain purified by b) into a bacterial enrichment medium for expansion culture;

[0016] As a preferred embodiment of the present invention, the culture medium is prepared according to the following ratio:

[0017] Bacteria selection medium: 20 g / L PHA powder, 0.25 g / L ammonium chloride, 0.015 g / L potassium dihydrogen phosphate, 0.035 g / L potassium hydrogen phosphate, 0.01 g / L anhydrous manganese sulfate, 0.03 g / L ferrous sulfate heptahydrate, 10 mg / L SMX, sterilized with high-pressure steam (e.g., high pressure 0.1 MPa, sterilization for 20 min) and ultrafiltered seawater (salinity 3.0%), and then sterilized again for use;

[0018] Bacterial solid culture medium: 15 g / L agar, 5 g / L sodium citrate dihydrate, 0.25 g / L ammonium chloride, 0.015 g / L potassium dihydrogen phosphate, 0.035 g / L potassium hydrogen phosphate, 0.01 g / L anhydrous manganese sulfate, 0.03 g / L ferrous sulfate heptahydrate, sterilized with high-pressure steam (e.g., high pressure 0.1 MPa, sterilization for 20 min) and ultrafiltered seawater (salinity 3.0%), and then sterilized again for use;

[0019] Bacteria enrichment medium: 20g / L PHA powder, 0.25g / L ammonium chloride, 0.15g / L potassium dihydrogen phosphate, 0.35g / L potassium hydrogen phosphate, 0.01g / L anhydrous manganese sulfate, 0.03g / L ferrous sulfate heptahydrate, 10mg / L SMX;

[0020] Preferably, in the application, the particle size of the bacterial culture medium PHA powder is 50 mesh to 200 mesh.

[0021] The application of Marinobacter nitratireducens LAN01 obtained in the present invention is used for denitrification and phosphorus removal of seawater aquaculture tail water; especially for denitrification and phosphorus removal of seawater aquaculture tail water containing antibiotics such as SMX. It can be used for the synchronous recovery of nutrients such as nitrogen and phosphorus under antibiotic stress conditions; it can convert ammonia nitrogen into bioflocs in seawater aquaculture tail water, achieve efficient carbon-nitrogen coupling treatment, and is easy to precipitate and separate.

[0022] Preferably, in the application, the concentrations of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen in the seawater aquaculture tail water are all below 50 mg / L.

[0023] Preferably, in the application, the concentration of phosphate in the seawater aquaculture tail water is below 20 mg / L.

[0024] Preferably, in the application, the concentration of antibiotics such as SMX in the seawater aquaculture tail water is below 20 mg / L.

[0025] Preferably, in the application, the temperature of the degradation process of denitrification and phosphorus removal of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen in the seawater aquaculture tail water is 15 - 40 °C.

[0026] Preferably, in the application, the pH of the denitrification and phosphorus removal process in the seawater aquaculture tail water is 7.5 - 9.5.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] 1. A strain of Marinobacter nitratireducens LAN01 with the ability of antibiotic-tolerant heterotrophic ammonia assimilation-aerobic denitrification screened and isolated in the present invention can exhibit good ammonia assimilation performance and assimilate phosphate under different concentrations of SMX stress, and synchronously reduce nitrite and nitrate nitrogen through denitrification, with stable treatment effect and high denitrification and phosphorus removal efficiency in the actual treatment of aquaculture tail water.

[0029] 2. This strain has good tolerance to the antibiotic SMX and has potential degradation ability. The degradation rate of low-concentration SMX (3.0 mg / L) is as high as 93.8%, and the degradation rate of 20 mg / L SMX can reach 29.1%. The main metabolic mechanism is biological absorption during ammonia assimilation, and a higher ammonia nitrogen / SMX ratio promotes the biotransformation of SMX.

[0030] 3. This strain synchronously absorbs nitrogen and phosphorus in the form of ammonia assimilation, promotes the recycling of nutrients in the tail water of seawater aquaculture, and has good flocculation and precipitation ability, being easy to separate. It can be used to enhance the nitrogen and phosphorus removal in seawater biological filters, showing broad application prospects in the fields of seawater aquaculture technology and ecological environment governance and restoration technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the phylogenetic tree diagram of the strain Marinobacter nitratireducens_LAN01;

[0032] Figure 2 It is the scanning electron microscope image of the strain Marinobacter nitratireducens_LAN01;

[0033] Figure 3 It is the removal effect and growth curve of ammonia nitrogen and phosphate in the culture medium by the strain Marinobacter nitratireducens_LAN01;

[0034] Figure 4 It is the removal effect and growth curve of nitrite nitrogen, nitrate nitrogen and phosphate in the culture medium by the strain Marinobacter nitratireducens_LAN01;

[0035] Figure 5 It is the comparison diagram of the removal effect of ammonia nitrogen by the strain Marinobacter nitratireducens_LAN01 under different concentrations of SMX stress conditions;

[0036] Figure 6 It is the nitrogen and phosphorus removal and SMX degradation effect diagram of the strain Marinobacter nitratireducens_LAN01 in the actual treatment of aquaculture tail water;

[0037] Figure 7 It is the nitrogen removal pathway of the strain Marinobacter nitratireducens_LAN01 predicted based on the KEGG database;

[0038] Figure 8 It is the whole genome map of the strain Marinobacter nitratireducens_LAN01. DETAILED DESCRIPTION OF THE INVENTION

[0039] The following will describe the present invention in detail with reference to the accompanying drawings.

[0040] To more clearly illustrate the purpose, technical solution and advantages of the present invention, the following provides a detailed description of the present invention in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0041] Example 1

[0042] Cultivation method: The bioflocs (passed through a 200-mesh filter screen) taken from the biological filter of seawater aquaculture tail water treatment in Lingshui Li'an Port, Hainan (110.06E, 18.43N) were inoculated into a bacterial selection medium and cultured with shaking in a shaker at 25°C and 180 r / min. The supernatant was taken every 24 h to detect ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and phosphate using an ultraviolet-visible spectrophotometer, and the concentration of targeted SMX was detected using HPLC-MS until the ammonia nitrogen degradation rate exceeded 80% after 24 h. Then, it was continuously acclimated and cultured for 2 cycles. 1 mL of the screened and acclimated bacterial culture solution (OD 600 = 0.4) was diluted, for example, 10 3 、10 4 、10 5 and 10 6 times, etc., with a sterile PBS solution, and then streaked on a solid medium for plate culture. The culture conditions were a constant temperature of 30°C. After 48 - 72 h, when colonies grew on the medium, single colonies were picked and purified 2 - 3 times, and then inoculated into a bacterial enrichment medium for enrichment culture, and its ability to remove nitrogen and phosphorus while being resistant to antibiotics was comprehensively investigated.

[0043] The measured 16S rDNA sequences were input into the GenBank database website of the NCBI website for similarity comparison, and a phylogenetic tree was drawn, Figure 1 as shown. The results showed that Marinobacter nitratireducens LAN01 had the highest similarity with Marinobacter nitratireducens. Combining physiological and biochemical characteristics, colony morphology, and heterotrophic ammonia assimilation characteristics, this strain was identified and named Marinobacter nitratireducens_LAN01.

[0044] Example 2

[0045] The method for measuring the physicochemical characteristics of nitrogen and phosphorus metabolism of Marinobacter nitratireducens LAN01 strain is as follows

[0046] (1) Inoculate Marinobacter nitratireducens LAN01 into the bacterial enrichment medium and culture it in a shaker at 25 °C and 180 r / min for 24 h to obtain an activated bacterial solution. ① Take the obtained activated bacterial solution of Marinobacter nitratireducens LAN01 and centrifuge it at 2500 rpm for 10 min; ② After removing the supernatant, resuspend and wash the bacterial cells with sterilized PBS solution; centrifuge at 2500 rpm for 10 min. ③ After resuspending the bacterial cells with PBS solution, inoculate them into the media containing ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen as nitrogen sources respectively according to an inoculation amount of 5%, and sample at time points to measure the utilization and transformation of various nitrogen sources by this strain.

[0047] The ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen media in the above method are prepared with ultrafiltered and sterilized seawater, the seawater salinity is 3.0%, and the other components are as follows:

[0048]

[0049] As Figure 3 shown, this strain can utilize ammonia nitrogen as a nitrogen source (corresponding to the ammonia assimilation medium), and no nitrite nitrogen and nitrate nitrogen are produced during the ammonia nitrogen degradation process, and phosphate is simultaneously degraded. In the presence of a high concentration of ammonia oxidation inhibitor, 100 mg / L allylthiourea (ATU) (i.e., adding a high concentration of ATU to the ammonia assimilation medium), this strain can still ensure effective ammonia nitrogen removal, proving that the nitrogen removal mechanism of strain LAN01 is mainly ammonia assimilation.

[0050] As Figure 4 shown, this strain can utilize nitrite and nitrate as nitrogen sources (corresponding to the denitrification medium), and simultaneously degrade phosphate. No nitrite nitrogen and ammonia nitrogen accumulation occur during the denitrification process, and the total nitrogen is converted into biomass without nitrogen loss.

[0051] Example 3

[0052] Antibiotic-resistant ammonia assimilation ability of Marinobacter nitratireducens LAN01 strain:

[0053] Strain LAN01 contains SMX resistance (sul1 and sul2) genes and potential degradation (sadA and sadC) genes. As Figure 5 shown, this strain can exert efficient ammonia assimilation under different stress conditions of 0 - 20 mg / L SMX (adding different concentrations of SMX to the ammonia assimilation medium in Example 2), and the removal rate of the initial ammonia nitrogen concentration of 45 mg / L can reach 100% within 8 h.

[0054] Example 4

[0055] Application of Marinobacter nitratireducens strain LAN01 in the treatment of actual seawater aquaculture wastewater

[0056] Using actual seawater aquaculture wastewater as the research object, the feasibility of treating aquaculture wastewater containing antibiotics by Marinobacter nitratireducens LAN01 at 25 °C and pH 7.6 was studied. The concentration of Marinobacter nitratireducens LAN01 in the aquaculture wastewater containing antibiotics was 3 g / L. As Figure 6 shown, in the actual aquaculture wastewater impacted by antibiotics, the SMX concentration was as high as 2.8 mg / L, and the ammonia nitrogen, nitrite nitrogen, nitrate nitrogen and phosphate were 3.6 mg / L, 0.3 mg / L, 7.7 mg / L and 1.6 mg / L respectively. The degradation rates of ammonia nitrogen and nitrite nitrogen were both 100% in 3 h, and the degradation rate of low-concentration SMX (3.0 mg / L) was as high as 93.8%. The above results indicate that strain LAN01 has good removal effects on nitrogen, phosphorus and antibiotics under the conditions of actual seawater aquaculture wastewater, which is better than native microorganisms and has good application potential.

[0057] Example 5

[0058] Analysis of the denitrification pathway of Marinobacter nitratireducens strain LAN01

[0059] As Figure 7 shown, the whole-genome identification results of Marinobacter nitratireducens strain LAN01 indicate that this bacterium contains a large number of ammonia assimilation (glnA and gdhA) genes, that is, it can assimilate ammonia nitrogen in aquaculture wastewater into organic nitrogen (bioflocs) to achieve the removal of ammonia nitrogen. However, it lacks ammonia oxidation (amoA and hao) genes and has a complete denitrification gene pathway, which proves that the denitrification mechanism of strain LAN01 is mainly heterotrophic ammonia assimilation and aerobic denitrification.

[0060] Appendix: 16S rRNA sequence of strain LAN01

[0061]

[0062] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A marine heterotrophic ammonia-assimilating and aerobic denitrifying bacterium Marinobacter nitratireducens LAN01 resistant to antibiotics, characterized in that, It was deposited on November 08, 2024 at the China General Microbiological Culture Collection Center (CGMCC), with the deposit name being LAN01 and the deposit number being: CGMCC No. 32548; the deposit address is: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, China, Zip Code: 100101.

2. An antibiotic-resistant marine heterotrophic ammonia assimilation-aerobic denitrifying bacterium Marinobacter nitratireducens LAN01 according to claim 1, characterized in that, Marinobacter nitratireducens LAN01 belongs to the strain in the species of Marinobacter nitratireducens; The biological characteristics of Marinobacter nitratireducens LAN01 are as follows: After culturing on nutrient agar medium at 30 °C for 48 - 72 h, it forms milky white colonies that are smooth, moist, opaque, and round on the surface, with a colony diameter of 1 - 2 mm; The cells of Marinobacter nitratireducens LAN01 are Gram-negative, rod-shaped, 0.3 - 0.5 μm wide × 1.0 - 2.0 μm long. Marinobacter nitratireducens LAN01 can grow on a liquid medium with one or several of NH4Cl, NaNO2, and KNO3 as nitrogen sources; The temperature required for the growth of Marinobacter nitratireducens LAN01 is 15 - 40 °C, the optimum growth temperature is 30 °C, the salinity required for growth is 2 - 4%, the pH required for growth is 7.5 - 9.5, the dissolved oxygen is 1 - 6 mg / L, and the rotation speed is 180 - 200 r / min.

3. A Marinobacter nitratireducens strain LAN01 with antibiotic tolerance, ammonia assimilation, and aerobic denitrification as claimed in claim 1, characterized in that, The 16S rRNA gene sequence is shown in the sequence listing.

4. A screening method for a strain of antibiotic-resistant Marinobacter nitratireducens LAN01 capable of heterotrophic ammonia assimilation and aerobic denitrification according to any one of claims 1-3, characterized in that, The screening method includes the following steps: a) Isolation of strains: Take the biological flocs in the biological filter using polyhydroxyalkanoate (PHA) as the solid carbon source. After intercepting through a 200-mesh filter screen, prepare a bacterial suspension using sterile seawater and transfer it into a bacterial selection medium for screening until the ammonia nitrogen degradation rate exceeds 80% in 24 h. Continue to acclimatize and culture for 2 cycles, and perform strain purification; b) Strain purification: Take 1 mL of the bacterial culture solution (OD 600 = 0.4) that has been screened and domesticated, dilute it with sterile PBS solution, and then perform streak plate culture on a solid medium. The culture conditions are a constant temperature of 30 °C. After 48 - 72 h, when colonies grow on the medium, pick single colonies; continue to purify the picked single colonies 2 - 3 times. The purification process is to domesticate the bacteria in the selective medium in step a and culture them on the solid medium in b; c) Inoculate the strain purified in b) into a bacterial enrichment medium for scale-up culture.

5. The method according to claim 4, wherein Dilute 10 3 to 6 10 times.

6. The method according to claim 4, wherein The medium is prepared according to the following ratio: Bacterial selection medium: 20 g / L PHA powder, 0.25 g / L ammonium chloride, 0.015 g / L potassium dihydrogen phosphate, 0.035 g / L dipotassium hydrogen phosphate, 0.01 g / L anhydrous manganese sulfate, 0.03 g / L ferrous sulfate heptahydrate, 10 mg / L SMX. Dissolve it using ultrafiltered seawater (salinity 3.0%) after high-pressure steam sterilization (for example, high pressure 0.1 Mpa, sterilization for 20 min), and then sterilize it again for use; Bacterial solid medium: 15 g / L agar, 5 g / L sodium citrate dihydrate, 0.25 g / L ammonium chloride, 0.015 g / L potassium dihydrogen phosphate, 0.035 g / L dipotassium hydrogen phosphate, 0.01 g / L manganese sulfate anhydrous, 0.03 g / L ferrous sulfate heptahydrate, dissolved with ultrafiltered seawater (salinity 3.0%) after autoclaving (e.g., at a high pressure of 0.1 Mpa for 20 min), and then autoclaved again before use; Bacterial enrichment medium: 20 g / L PHA powder, 0.25 g / L ammonium chloride, 0.15 g / L potassium dihydrogen phosphate, 0.35 g / L dipotassium hydrogen phosphate, 0.01 g / L manganese sulfate anhydrous, 0.03 g / L ferrous sulfate heptahydrate, 10 mg / L SMX; The particle size of the PHA powder in the bacterial medium is 50 mesh to 200 mesh.

7. Use of a strain of antibiotic-resistant marine heterotrophic ammonia assimilation-aerobic denitrifying Marinobacter nitratireducens LAN01 according to any one of claims 1-3 for nitrogen and phosphorus removal from seawater aquaculture tail water; particularly for nitrogen and phosphorus removal from seawater aquaculture tail water containing antibiotics such as SMX.

8. Use of a strain of antibiotic-resistant marine heterotrophic ammonia assimilation-aerobic denitrifying Marinobacter nitratireducens LAN01 according to any one of claims 1-3 for synchronous recovery of nutrients such as nitrogen and phosphorus under antibiotic stress conditions.

9. Use of a strain of antibiotic-resistant marine heterotrophic ammonia assimilation-aerobic denitrifying Marinobacter nitratireducens LAN01 according to any one of claims 1-3 for converting ammonia nitrogen into bioflocs in seawater aquaculture tail water, achieving efficient carbon-nitrogen coupling treatment, and being easy to precipitate and separate.

10. The use according to any one of claims 7-9, wherein the concentrations of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen in the seawater aquaculture tail water are all below 50 mg / L; The concentration of phosphate in the seawater aquaculture tail water is below 20 mg / L; The concentration of antibiotics such as SMX in the seawater aquaculture tail water is below 20 mg / L; The temperature of the degradation process of nitrogen and phosphorus removal of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen in the seawater aquaculture tail water is 15-40 °C; The pH of the nitrogen and phosphorus removal process in the seawater aquaculture tail water is 7.5-9.5.

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