Seawater efficient heterotrophic nitrification and aerobic denitrification strain and application thereof

Abstract

The invention relates to the technical field of microorganisms, in particular to a seawater efficient heterotrophic nitrification and aerobic denitrification strain and application thereof. The strain is Marinobacter sp. TF26-2, and is preserved in the China General Microbiological Culture Collection Center (CGMCC) on May 27, 2024, the preservation address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the preservation number is CGMCC No.30778. The invention further discloses a preparation method of the strain. The marinobacter TF26-2 provided by the invention has the functions of heterotrophic nitrification and aerobic denitrification at the same time, and can be used in the field of sewage treatment. The strain shows a good denitrification effect under different environmental conditions, is safe to aquatic organisms, and is especially suitable for being used as probiotics or an environmental modifier in the fields of mariculture and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, and in particular to a seawater high-efficiency heterotrophic nitrification and aerobic denitrification bacterial strain and application thereof. Background Art

[0002] With the depletion of marine fishery resources and the growing demand for seafood, the scale of mariculture has steadily increased in recent years, becoming an important means for people to obtain seafood. my country is a major mariculture country, and mariculture plays a vital role in ensuring national food security. However, with the continuous increase in the scale and density of mariculture, the environmental pollution caused by aquaculture has become increasingly serious. In recent years, my country has strengthened its supervision of mariculture pollution, and coastal provinces have successively issued a series of local standards to limit the discharge of mariculture tailwater. Currently, environmental pollution has become a major factor restricting the sustainable development of the mariculture industry.

[0003] During the aquaculture process, low-quality feed, the leaching of shrimp excrement, and the dissolution of biological remains lead to large amounts of nitrogen and phosphorus compounds in aquaculture tailwater. Uncontrolled discharge of this wastewater into the environment can lead to pollution of aquaculture areas and even a series of environmental problems, such as red tides. Among the excess nutrients, such as nitrogen and phosphorus, nitrogen pollution is of particular concern. Studies have shown that high concentrations of ammonia nitrogen can severely damage the gill tissue and immune system of aquatic animals, increasing mortality rates. Nitrite can affect the oxygen-carrying capacity of aquatic organisms and even cause their death. Nitrate is less toxic than ammonia nitrogen and nitrite, but high concentrations can increase the susceptibility of aquatic organisms to various diseases. Therefore, the problem of nitrogen compound pollution in aquaculture environments needs to be urgently addressed.

[0004] Currently, denitrification methods include physical, chemical, and biological methods. Biological methods have become the most promising denitrification method in the aquaculture industry due to their high efficiency, strong economy, and lack of secondary pollution. However, traditional biological denitrification technology requires different environmental conditions to be completed in stages, which has the disadvantages of high operating costs and large floor space. In recent years, heterotrophic nitrifying aerobic denitrifying strains have attracted widespread attention due to their high removal rates of ammonia nitrogen, nitrite, and nitrate under aerobic conditions. Compared with traditional denitrifying microorganisms, heterotrophic nitrifying aerobic denitrifying strains have higher cell growth rates and faster denitrification rates, and there is almost no accumulation of nitrite and nitrate during the reaction process. The simultaneous nitrification and denitrification process based on heterotrophic nitrifying aerobic denitrifying microorganisms can achieve simultaneous denitrification in the same reactor, simplifying the process flow, shortening the hydraulic retention time, and thus greatly reducing water treatment costs. Currently, most of the heterotrophic nitrifying and aerobic denitrifying bacteria isolated come from freshwater environments and have poor activity in high-salt environments such as seawater. Therefore, the development of heterotrophic nitrifying and aerobic denitrifying bacteria in seawater environments is of great significance and is expected to solve the problem of nitrogen pollution in marine aquaculture. Summary of the Invention

[0005] In view of the problems existing in the prior art, the main purpose of the present invention is to provide a seawater high-efficiency heterotrophic nitrification and aerobic denitrification strain and its application.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A strain of Marinobacter sp., which is Marinobacter sp. TF26-2, was deposited in the General Microbiology Center of the China Culture Collection Administration (CGMCC) on May 27, 2024. The deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 30778.

[0008] The Marinobacterium TF26-2 is a Gram-negative bacterium. Its colonies on 2216E agar are milky white, round, with neat edges and a smooth surface, making them easy to pick. It has the biological characteristics of both heterotrophic nitrification and aerobic denitrification.

[0009] The total genome length of the Marinobacterium TF26-2 is 4285951 bp, the G+C content is 57.24%, and it contains 3925 predicted protein coding sequences (CDSs), accounting for 90.69% of the complete genome.

[0010] An application of the Marinobacterium, wherein the application of the Marinobacterium is in heterotrophic nitrification and / or aerobic denitrification.

[0011] The application of the Marinobacter sp. TF26-2 in treating nitrogen-containing water environments.

[0012] The application of the Marinobacter sp. TF26-2 in treating nitrogen-containing wastewater.

[0013] The application of the Marinobacter sp. TF26-2 in treating aquaculture tail water.

[0014] The aquaculture tail water is fresh water, brackish water or sea water.

[0015] A heterotrophic nitrification and aerobic denitrification bacterial agent containing the strain.

[0016] An application of the heterotrophic nitrification and aerobic denitrification bacterial agent, and an application of the bacterial agent in heterotrophic nitrification and / or aerobic denitrification.

[0017] The bacterial agent is used in the treatment of nitrogen-containing wastewater.

[0018] The bacterial agent uses one or more of glucose, sodium acetate, sodium citrate and sodium succinate as carbon sources and is used to treat sewage with a C / N ratio of 5 to 20 and a salinity range of 0‰ to 40‰.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) The present invention's Marinobacterium TF26-2 possesses both heterotrophic nitrification and aerobic denitrification capabilities. Under aerobic conditions, the strain achieved a 24-hour ammonia nitrogen removal rate of 99.8%, with a maximum ammonia nitrogen removal efficiency of 3.79 mg / L / h. No accumulation of nitrite or nitrate occurred during the ammonia nitrogen removal process. Nitrogen balance analysis revealed that the strain could convert over 45% of ammonia nitrogen into a gaseous nitrogen excretion system, demonstrating that the strain itself can achieve both nitrification and denitrification.

[0021] (2) The heterotrophic nitrifying aerobic denitrifying Marinobacterium TF26-2 of the present invention has a good nitrogen removal effect in a variety of carbon sources. Its ammonia nitrogen removal rate within 24 hours is above 98% when glucose, sodium acetate, sodium citrate or sodium succinate is the sole carbon source, and the nitrite and nitrate removal rate can reach 99.8% when sodium acetate or sodium succinate is the sole carbon source.

[0022] (3) The heterotrophic nitrifying aerobic denitrifying Marinobacterium TF26-2 of the present invention has a good nitrogen removal effect in a wide range of carbon-nitrogen ratios. Its removal rate of nitrite and nitrate can reach more than 94.8% within a carbon-nitrogen ratio range of 5 to 20 within 24 hours.

[0023] (4) The heterotrophic nitrifying aerobic denitrifying Marinobacterium TF26-2 of the present invention has a good nitrogen removal effect in a wide salinity range. Its ammonia nitrogen removal rate within 24 hours is higher than 97% within the salinity range of 0‰ to 40‰; and its nitrite removal rate within the salinity range of 10‰ to 40‰ is higher than 99.9%.

[0024] (5) The heterotrophic nitrifying aerobic denitrifying Marinobacter TF26-2 of the present invention is a biosafety strain. 7 It is harmless to Litopenaeus vannamei at low CFU / mL concentrations and can be used as a probiotic or environmental improver in aquaculture.

[0025] (6) Genes related to nitrogen cycle were found in the genome of the heterotrophic nitrifying aerobic denitrifying Marinobacter TF26-2 of the present invention, including but not limited to the gene nxrB encoding nitrite oxidoreductase, the gene napA encoding nitrate reductase, the gene nirB encoding nitrite reductase, the gene nosZ encoding nitrous oxide reductase, etc., further confirming the heterotrophic nitrifying aerobic denitrification characteristics of the strain at the genetic level. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a 16S rRNA phylogenetic tree diagram of Marinobacterium TF26-2 in the examples of the present invention.

[0027] Figure 2 This is a graph showing the removal of ammonia nitrogen by Marinobacterium TF26-2 in an example of the present invention.

[0028] Figure 3 This is a diagram showing the denitrification effect and growth of Marinobacterium TF26-2 under different carbon source conditions in an example of the present invention.

[0029] Figure 4 This is a diagram showing the denitrification effect and growth of Marinobacterium TF26-2 under different carbon-nitrogen ratios in an embodiment of the present invention.

[0030] Figure 5 This is a diagram showing the denitrification effect and growth of Marinobacterium TF26-2 under different salinity conditions in an example of the present invention. DETAILED DESCRIPTION

[0031] The drawings that constitute part of the embodiments of the inventions provided in this specification are used to assist in understanding the embodiments of the inventions provided in this specification. The contents provided in the drawings and their related descriptions in the embodiments of the inventions provided in this specification can be used to explain the embodiments of the inventions provided in this specification, but do not constitute improper limitations on the embodiments of the inventions provided in this specification.

[0032] In order to more clearly illustrate the technical features, objectives and beneficial effects of the present invention, Figure 1-5 The present invention is further described in detail with reference to the accompanying drawings and embodiments. The following is a detailed description of the technical solution of the present invention, but it should not be understood as limiting the scope of implementation of the present invention.

[0033] Unless otherwise specified, the experimental materials, reagents, or devices used in the present invention can be obtained from conventional commercial channels.

[0034] In the following examples, 2216E liquid medium and 2216E solid medium for marine bacterial enrichment were purchased from Qingdao Haibo Biotechnology Co., Ltd. Their composition (g / L) was as follows: 5.0 g of peptone, 1.0 g of yeast extract, 0.1 g of ferric citrate, 19.45 g of sodium chloride, 5.98 g of magnesium chloride, 3.24 g of sodium sulfate, 1.8 g of calcium chloride, 0.55 g of potassium chloride, 0.16 g of sodium carbonate, 0.08 g of potassium bromide, 0.034 g of strontium chloride, 0.022 g of boric acid, 0.004 g of sodium silicate, 0.0024 g of sodium fluoride, 0.0016 g of ammonium nitrate, and 0.008 g of disodium hydrogen phosphate. The solvent was deionized water, and the pH was 7.6 ± 0.2. The solid 2216E medium used consisted of the above-mentioned 2216E liquid medium supplemented with 1.5% agar.

[0035] The composition of the EM medium used for strain enrichment culture is (g / L): ammonium sulfate 0.5, sodium nitrite 0.5, sodium acetate 0.1, sodium chloride 30, ferrous sulfate 0.03, magnesium sulfate 0.03, potassium dihydrogen phosphate 1.0, calcium chloride 1.0, and the solvent is distilled water.

[0036] The following NM and DM culture media are single nitrogen source culture media used to simulate marine aquaculture tail water. Their specific components are as follows:

[0037] The composition of NM medium is (g / L): ammonium sulfate 0.096, sodium acetate 0.344, dipotassium hydrogen phosphate 0.004, potassium dihydrogen phosphate 0.004, and the solvent is filtered seawater (0.22 μm filter membrane).

[0038] The composition of DM1 medium is (g / L): sodium nitrite 0.100, sodium acetate 0.344, dipotassium hydrogen phosphate 0.004, potassium dihydrogen phosphate 0.004, and the solvent is filtered seawater (0.22 μm filter membrane).

[0039] The composition of DM2 medium is (g / L): potassium nitrate 0.144, sodium acetate 0.344, dipotassium hydrogen phosphate 0.004, potassium dihydrogen phosphate 0.004, and the solvent is filtered seawater (0.22 μm filter membrane).

[0040] The initial pH value of the above culture medium was adjusted to 7.2±0.2, 2% agar was added to prepare solid plates, and the plates were autoclaved at 121°C for 20 min before use.

[0041] In the following examples, water quality testing was performed according to the standard method in the "Ocean Monitoring Specification for Seawater Analysis" (GB 17378.4-2007). - -N, NO3 - -N, TAN and TN were determined by N-(1-naphthyl)-2-ethylenediamine spectrophotometry, zinc cadmium reduction method, hypobromite oxidation method and alkaline potassium persulfate spectrophotometry, respectively.

[0042] Cell optical density (OD 600 ) was determined using a microplate scanning spectrophotometer (Power Wave XS2, BioTec, USA).

[0043] Example 1

[0044] The breeding process of the heterotrophic nitrifying aerobic denitrifying Marinobacter TF26-2 provided in this embodiment comprises the following steps:

[0045] (1) Enrichment of strains: The experimental samples were taken from a shrimp seawater aquaculture pond in Dongying, Shandong Province. 5.0 mL of the sample was taken and added to 500 mL of sterilized EM medium and cultured at 30°C and 160 rpm for 5 days. Then 5 mL of the enrichment solution was transferred to freshly prepared EM and cultured again at 30°C and 160 rpm for 5 days. The enrichment process was repeated three times.

[0046] (2) Isolation, purification, and preservation of strains: Take the third enrichment solution and dilute it to the appropriate concentration using PBS buffer. Spread 100 μL of the dilution onto a Seawater 2216E solid plate and incubate at 30°C. Pick a single colony and perform streak purification. The purified strains are numbered and stored in a -20°C freezer using 25% glycerol.

[0047] (3) Screening of heterotrophic nitrifying and aerobic denitrifying bacteria: The isolated and purified strains were inoculated into 2216E liquid culture medium and cultured at 30°C and 160 rpm until the OD 600 When the value reached 0.6, the bacteria were inoculated at a 1% (v / v) ratio into sterilized NM and DM1 culture media. Cultures were shaken at 30°C and 160 rpm for 48 hours, and the supernatant was centrifuged. Ammonia nitrogen and nitrite concentrations in the supernatant were measured. Three replicates were set up for each strain, and a control group was left uninoculated. A strain with high and stable heterotrophic nitrification and aerobic denitrification efficiency was selected, and Marinobacter TF26-2 was obtained.

[0048] The strain Marinobacter sp. TF26-2 was deposited in the General Microbiology Center of the China Culture Collection Administration (CGMCC) on May 27, 2024. The deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 30778.

[0049] Example 2

[0050] The steps for identifying the biological and other related characteristics of the screened Marinobacterium TF26-2 include:

[0051] (1) Morphological identification: After the above screening and separation, a heterotrophic nitrification-aerobic denitrification strain TF26-2 was obtained. This strain is a Gram-negative bacterium. The colonies on 2216E agar are milky white, round, with neat edges and a smooth surface, and are easy to pick.

[0052] (2) Molecular biological identification: Bacterial genomic DNA was extracted using the TIANamp bacterial genomic DNA extraction kit (Tiangen Biochemical Technology Co., Ltd.). The universal primers 27F / 1492R were used to amplify the 16S rRNA sequence of the strain. The PCR product sequencing was completed by Beijing Qingke Biotechnology Co., Ltd. The gene sequence obtained by sequencing was compared with the 16S rRNA gene sequence in the NCBI database. It was found that the strain TF26-2 showed a high homology with a variety of Marinobacter species, among which the similarity with the strain Marinobacter sp. KU17G3 reached 99.72%. The phylogenetic tree was constructed using the Neighbor-Joining (NJ) method using MEGA11 software (see Figure 1 ), it was found that strain TF26-2 was most closely related to Marinobacter. Combined with the strain morphology, the strain was identified as Pseudomonas, γ-Proteobacteria, Pseudomonadales, Marinobacteriaceae, Marinobacter genus, and named Marinobacter sp. TF26-2.

[0053] Example 3

[0054] Genome analysis of strains

[0055] DNA from the strain was extracted using SDS extraction combined with purification columns. DNA quality was tested using Nanodrop and Qubit electrophoresis. Sequencing was performed using the NovaSeq 6000 (Illumina, USA) second-generation sequencing platform and the PromethION (Nanopore, UK) third-generation sequencing platform. Filtered reads were assembled using Unicycler software. The assembled genome of the strain was predicted using Prokka software. The predicted gene sequences were compared with functional databases to obtain gene annotation information.

[0056] Sequencing results revealed that the genome of Marinobacter TF26-2 is 4,285,951 base pairs in length, with a G+C content of 57.24%. It contains 3,925 predicted protein-coding sequences (CDSs), representing 90.69% of the complete genome. Genes related to the nitrogen cycle were identified in the Marinobacter TF26-2 genome, including nxrB, encoding nitrite oxidoreductase; napA, encoding nitrate reductase; nirB, encoding nitrite reductase; and nosZ, encoding nitrous oxide reductase. These findings further confirm the strain's heterotrophic nitrification and aerobic denitrification characteristics at the genetic level.

[0057] Example 4

[0058] The Marinobacterium TF26-2 obtained above was applied to the field of marine aquaculture tail water denitrification, and its denitrification performance was measured. The specific steps are as follows:

[0059] The strain was inoculated into 2216E liquid medium at a ratio of 1% (v / v) and cultured at 30°C and 160 rpm for 12 hours. The bacterial solution was then centrifuged and the supernatant removed. The remaining bacterial pellet was washed twice with sterilized NM medium and resuspended to an OD of 600 =0.6 to remove the influence of the previous culture medium. The resuspended bacterial suspension was inoculated into NM culture medium at a ratio of 1% (v / v) and cultured at 160 rpm and 30°C for 24 hours. Samples were taken regularly to analyze the optical density (OD 600 ), and after centrifugation at 6500 rpm for 5 minutes, TAN, NO2 - -N, NO3 - -N and soluble total nitrogen (TN) concentrations. Take samples without centrifugation to measure initial and final TN (see Figure 2 ).

[0060] Depend on Figure 2It can be seen that the removal rate of ammonia nitrogen by Marinobacterium TF26-2 under simulated seawater aquaculture conditions is as high as 99.8% in 24 hours, the maximum ammonia nitrogen removal efficiency is 3.79 mg / L / h, and there is no accumulation of nitrite and nitrate during the ammonia nitrogen removal process, indicating that this strain has a good ammonia nitrogen removal effect.

[0061] Example 5

[0062] The aforementioned Marinobacterium TF26-2 is applied to the field of sewage treatment, and the testing and verification of its optimal growth and denitrification conditions include the following steps:

[0063] (1) Setting of different environmental factors: In the carbon source experiment, glucose, sucrose, sodium acetate, sodium succinate, and sodium citrate were selected as the sole carbon source, respectively. The initial concentrations of (NH4)2SO4, NaNO2, and KNO3 were 20 mg / L (C / N=10). For the C / N ratio experiment, sodium acetate was used to adjust the C / N ratio of the solution to 0, 5, 10, 15, and 20 to explore their removal effects on different forms of nitrogen compounds ((NH4)2SO4, NaNO2, and KNO3, 20 mg / L). For the salinity experiment, the medium used in the culture medium was deionized water instead of seawater. In order to supplement the elements required by the microorganisms, the following (g / L) were added to the culture medium: 0.03FeSO4·7H2O, 0.03MgSO4·7H2O, 0.5CaCl2, 0.01MnSO4·4H2O, 0.5CaCO3, 0.75KH2PO4, and 0.75Na2HPO4. The salinity (‰) of the culture medium (C / N = 10) was adjusted to 0, 10, 20, 30, and 40 using sodium chloride. Other conditions were the same as those in the C / N ratio experiment. The culture medium was autoclaved before use.

[0064] (2) Preparation of seed solution and formal experiment: The experimental strain was inoculated into 2216E medium overnight to activate the strain, and washed twice with sterile saline to remove the influence of the previous culture medium. The bacterial solution was resuspended with sterile saline to OD 600 =0.6, inoculated into the above culture medium at a ratio of 1% (v / v). Then cultured at 160 rpm and 30°C for 24 hours. Samples were taken to measure the optical density (OD 600 After centrifugation at 6500 rpm for 5 minutes, TAN and NO2 were measured. - -N and NO3 - -N concentration (see Figure 3-5 ).

[0065] Figure 3The results show the nitrogen removal and growth performance of Marinobacterium TF26-2 under different carbon source conditions. The results show that the strain's ammonia nitrogen removal rate is over 98% when glucose, sodium acetate, sodium citrate, or sodium succinate are the sole carbon sources, and its nitrite and nitrate removal rates reach 99.8% when sodium acetate or sodium succinate are the sole carbon sources.

[0066] Figure 4 The nitrogen removal and growth performance of Marinobacterium TF26-2 under different carbon-nitrogen ratios was shown. The results showed that strain TF26-2 had excellent removal of ammonia nitrogen, nitrite, and nitrate within a carbon-nitrogen ratio range of 5 to 20. The strain achieved the highest biomass after 24 hours when ammonia nitrogen was the sole nitrogen source and the carbon-nitrogen ratio was 15.

[0067] Figure 5 The results show the nitrogen removal and growth performance of Marinobacterium TF26-2 under different salinity conditions. The results show that at salinity levels between 0‰ and 40‰, the strain's ammonia nitrogen removal rate exceeded 97%, and its nitrate removal rate exceeded 74.9%. At salinity levels between 10‰ and 40‰, its nitrite removal rate exceeded 99.9%.

[0068] Example 6

[0069] Biosafety evaluation of strains

[0070] Healthy Litopenaeus vannamei (35 ± 0.81 g) were cultured for one week before the experiment. 100 L of clean seawater was added to each of the six culture tanks, and 24 shrimp were randomly assigned to each tank. The cultured TF26-2 bacterial solution was added to the experimental group to a final concentration of 10 7 cfu / mL. The control group received the same volume of sterilized seawater, with triplicate replicates for each group. Feed the shrimp three times daily at a feed rate of 3% of the shrimp volume. Daily water changes were performed at one-third of the culture water volume. After water changes, the appropriate volume of bacterial solution and sterile seawater was promptly replenished to maintain the experimental bacterial solution concentration. Shrimp were cultured for 7 days in an environment maintained at a temperature of 28-29°C, a dissolved oxygen concentration (DO) of 4.0-5.0 mg / L, and a pH of 7.5-8.1. The shrimp's health was observed daily, and any dead shrimp were removed promptly for inclusion in the survival rate.

[0071] Table 1. Survival statistics of the group with TF26-2 bacterial solution and the control group

[0072]

[0073] The results showed that the shrimps in the bacterial solution group and the control group were in good condition, and there was no significant difference in the survival rate of the shrimps in the two groups, indicating that the strain was effective in the treatment of 10 7The strain is harmless to Litopenaeus vannamei under cfu / mL concentration conditions and is a biosafety strain that can be used in aquaculture.

[0074] In summary, the strain TF26-2 bred in this invention has no adverse effects on aquacultured animals when applied to marine aquaculture tailwater treatment and in marine aquaculture ponds, exhibits high aquatic biosafety, and is suitable for use in most aquaculture waters. Under aerobic conditions, this strain can simultaneously remove ammonia nitrogen, nitrite, and nitrate from water, resolving the need for separate nitrification and denitrification processes in traditional tailwater treatment. This significantly reduces the footprint and operating costs of tailwater treatment projects, offering excellent economic and environmental benefits and promising applications.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A strain of Marinobacterium, characterized in that The strain is Marinobacter sp. TF26-2, which was deposited in the General Microbiology Center of China Microorganism Culture Collection (CGMCC) on May 27, 2024. The deposit address is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 30778.

2. A use of the Marinobacterium according to claim 1, characterized in that: The application of the Marinobacterium in heterotrophic nitrification and / or aerobic denitrification.

3. The use of the Marinobacterium according to claim 2, characterized in that: The application of the Marinobacter sp. TF26-2 in treating nitrogen-containing water environments.

4. The use of Marinobacterium according to claim 3, characterized in that: The application of the Marinobacter sp. TF26-2 in treating nitrogen-containing wastewater.

5. The use of Marinobacterium according to claim 4, characterized in that: The application of the Marinobacter sp. TF26-2 in treating aquaculture tail water.

6. The use of Marinobacterium according to claim 5, characterized in that: The aquaculture tail water is fresh water, brackish water or sea water.

7. A heterotrophic nitrification and aerobic denitrification bacterial agent, characterized in that: The bacterial agent contains the strain described in claim 1.

8. An application of the heterotrophic nitrification and aerobic denitrification bacterial agent according to claim 7, characterized in that: The bacterial agent is used in heterotrophic nitrification and / or aerobic denitrification.

9. The use of the heterotrophic nitrification and aerobic denitrification bacterial agent according to claim 8, characterized in that: The bacterial agent is used in treating nitrogen-containing wastewater.

10. The use of the heterotrophic nitrification and aerobic denitrification bacterial agent according to claim 9, characterized in that: The bacterial agent uses one or more of glucose, sodium acetate, sodium citrate and sodium succinate as carbon sources and is used to treat sewage with a C / N ratio of 5 to 20 and a salinity range of 0‰ to 40‰.

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