A strain, biological composition and method suitable for denitrification treatment of hypersaline water bodies

Abstract

This invention belongs to the field of microbiology and water treatment technology, and relates to a strain, biological composition, and method suitable for denitrification treatment of high-salinity water. The biological composition is *Tritonella motilityis*, with accession number CGMCC No. 38221. Tritonibacter mobile s, CGMCC No. 38222 of Bacillus glutamate Glutamicibacter sp . Cape Paracoccus, CGMCC No. 38223 Paracoccus hominiensis Composition. This invention utilizes the synergistic effect of microorganisms with different biological functions to accelerate and enhance the biological nitrogen removal process in recirculating aquaculture systems suitable for marine aquaculture, while simultaneously achieving NH4+ removal. + - N, NO2 ‑ - N and NO3 ‑ It can effectively remove -N; it can also be used for biological nitrogen removal in aquaculture wastewater.

Description

Technical Field

[0001] This invention belongs to the field of microbial and water treatment technology, and relates to a strain, biological composition and method suitable for the treatment of recirculating water and tailwater in marine aquaculture. Background Technology

[0002] Recirculating aquaculture is an aquaculture model that integrates water treatment and intensive farming. In this multi-stage water treatment process, the biological treatment stage is the primary site for removing dissolved nitrogen compounds. In seawater recirculating aquaculture, the biological treatment stage typically employs a moving bed biofilm reactor (MBBR) process based on biofilm technology. In an MBBR, nitrifying bacteria on the surface of the biological carrier can remove toxic NH4+. + -N and NO2 - -N is converted to NO3 - -N, thereby reducing NH4+ in the water. + -N and NO2 - -N's harm to aquatic organisms can be mitigated through water recycling. MBBR can also be used for denitrification of marine aquaculture wastewater, reducing its harm to the surrounding environment. However, the high salinity of marine aquaculture wastewater significantly inhibits biofilm formation and nitrifying bacteria colonization (Fan & Sun, 2024, Jiang et al., 2025), thus prolonging the start-up period of MBBR systems (Li et al., 2019). This increases the operating costs of marine recirculating aquaculture systems and greatly limits their development.

[0003] The study by Tadda et al. (2021) found that inoculating mature biofilms into seawater MBBRs achieved NH4+ + -N (removal rate 95.3%) and NO2 - - Highly efficient removal of N (removal rate 99.6%), but NO3 - -N accumulated significantly, not only failing to degrade but also increasing from 50 mg / L to 77.60 mg / L. Li et al. (2019) found that gradually increasing the influent salinity could effectively accelerate the start-up of the MBBR, 16-18 days earlier than the untreated control group, but it also resulted in the accumulation of large amounts of NO3. - -N. Since nitrate accumulation also has a serious impact on aquatic animals and the surrounding aquatic environment, the biological treatment sections of recirculating aquaculture systems and the biological treatment processes for aquaculture wastewater urgently need to be able to simultaneously degrade NH4+. + - N, NO2 - - N and NO3 - -N biological treatment technology. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a bacterial strain, biological composition, and method suitable for denitrification treatment in high-salinity water bodies. Through the synergistic effect of microorganisms with different biological functions, it accelerates and enhances the biological nitrogen removal process in recirculating aquaculture systems suitable for marine aquaculture, simultaneously achieving NH4+ removal. + - N, NO2 - - N and NO3 - Highly efficient removal of -N. This technology can also be used for biological nitrogen removal in aquaculture wastewater.

[0005] The technical solution adopted in this invention is as follows: a strain suitable for denitrification treatment in high-salinity water, wherein the strain is *Tritonella motilityis*. Tritonibacter mobilis It was deposited on April 13, 2026 at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 38221.

[0006] Furthermore, the present invention provides another strain suitable for denitrification treatment in high-salinity water bodies, said strain being *Bacillus glutamicum*. Glutamicibacter sp. was deposited on April 13, 2026 at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 38222.

[0007] Furthermore, the present invention provides another strain suitable for denitrification treatment in high-salinity water, said strain being *Paracococcus faecium*. Paracoccus homiensis It was deposited at the China General Microbiological Culture Collection Center (CGMCC) on April 13, 2026, with accession number CGMCC No. 38223.

[0008] Furthermore, the present invention also provides a biological composition suitable for denitrification treatment of high-salinity water, the biological composition being *Tritonella motilityis* with accession number CGMCC No. 38221. Tritonibacter mobili s, CGMCC No. 38222 of Bacillus glutamicum Glutamicibacter sp., CGMCC No. 38223, *Paracoccus capillaris* Paracoccus homiensis composition.

[0009] Furthermore, the present invention provides the use of the biological composition for preparing microbial agents for the treatment of recirculating aquaculture water and tailwater in marine aquaculture.

[0010] Furthermore, the present invention provides a bacterial agent suitable for denitrification treatment of high saline water bodies, the bacterial agent comprising the aforementioned biological composition.

[0011] Furthermore, the present invention provides a method for denitrification treatment of high-salinity water bodies, the method comprising: inoculating the biological composition or bacterial agent into the water body to be treated.

[0012] Preferably, the biological composition or microbial agent is inoculated into a seawater moving bed biofilm reactor in the water body to be treated.

[0013] The beneficial effects of this invention are as follows: This invention screened three new bacterial strains, including two heterotrophic nitrifying-aerobic denitrifying bacteria (CGMCC No. 38223 and CGMCC No. 38222) and one bacterium with high biofilm formation capacity (CGMCC No. 38221). Through the synergistic effect of microorganisms with different biological functions, the biological nitrogen removal process in recirculating aquaculture systems suitable for marine aquaculture is accelerated and enhanced, simultaneously achieving NH4+ removal. + - N, NO2 - - N and NO3 - It is highly efficient at removing -N; it can also be used for biological nitrogen removal in aquaculture wastewater. Attached Figure Description

[0014] Figure 1 The images show the colony morphology of each strain on a 2216E plate and the cell morphology under SEM in the embodiments of the present invention; from left to right, they are strains NI-11, NI-8 and W-1, and the SEM magnification is 20000×. Figure 2 This is the phylogenetic tree of the three strains screened in this embodiment of the invention; Figure 3 This invention illustrates the removal effects of a single strain and a synthetic bacterial community composed of three strains on different types of nitrogen compounds in the embodiments of the present invention; wherein, (a) NH4 + -N; (b)NO2 - -N; (c)NO3 - -N; Figure 4 The co-culture performance of the three strains; including (a) changes in biomass; (b) absolute viable count; and (c) relative proportions and dominance shifts. Figure 5 Schematic diagram of MBBR device and K5 carrier; Figure 6 The denitrification effect of moving bed biofilm reactors (MBBR) inoculated with different combinations of bacterial communities was studied. Among them, MBBR1 was not inoculated with any bacteria, MBBR2 was inoculated with NI-8+NI-11+W-1, MBBR3 was inoculated with NI-8+NI-11, MBBR4 was inoculated with NI-8+W-1, MBBR5 was inoculated with NI-11, and MBBR6 was inoculated with W-1. Figure 7Biofilm formation on the carriers during the start-up of each moving bed biofilm reactor. Detailed Implementation

[0015] To facilitate understanding of the present invention, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and specific examples. The following examples or drawings are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0016] This invention isolated a series of HN-AD (heterotrophic nitrifying-aerobic denitrifying bacteria) bacteria from seawater RAS. Using a top-down strategy, the HN-AD bacterial community was constructed by combining the heterotrophic nitrification-aerobic denitrification ability and colonization ability of the microorganisms. The denitrification ability and mechanism of the synthetic bacterial community were characterized, with the aim of providing an effective alternative for the bioaugmentation of seawater aquaculture tailwater treatment.

[0017] I. Enrichment, Isolation and Purification of Bacteria 1. Preparation of culture medium The enrichment medium (EM) contains the following components (g / L): 0.5 (NH4)2SO4, 0.5 NaNO2, 0.1 CH3COONa, 0.03 FeSO4·7H2O, 0.03 MgSO4·7H2O, 1 KH2PO4, 1 CaCl2 and 1 L filtered seawater (0.22 μm filter membrane). Nitrification medium (NM) and denitrification medium (DM1 and DM2) were prepared according to previous research (Liu et al., 2023) to simulate marine aquaculture wastewater. NM contained the following components (g / L): 0.344 g sodium acetate, 0.096 g (NH4)2SO4, 0.004 g K2HPO4·3H2O, 0.004 g KH2PO4, and 1 L of filtered seawater (0.22 μm filter membrane). DM1 and DM2 used 0.100 g NaNO2 and 0.144 g KNO3, respectively, to replace the (NH4)2SO4 in NM, with the remaining components being the same as NM.

[0018] The bacterial strain was purified and preserved using 2216E medium. The pH of the medium was adjusted to 7.5 ± 0.3. Solid medium was prepared by adding 2% (w / v) agar to the above medium. All reagents used in this study were of analytical grade. All media were autoclaved at 121°C for 20 min before use.

[0019] 2. Screening of strains Experimental samples were obtained from the biofilm and water of the MBBR (Mass Bacterial Biofilm Reactor) in a Litopenaeus vannamei seawater recirculating aquaculture system (Dongying, China). 10 g of sample was added to 200 mL of sterile EM (Effective Microorganisms) and incubated at 30 ℃ with shaking at 160 r / min for 3 days. Subsequently, 10 mL of the above culture medium was transferred to 200 mL of EM and incubated under the same conditions. This process was repeated three times to enrich the target bacterial population.

[0020] Take the final enrichment solution and perform serial dilutions using sterile PBS buffer, selecting an appropriate dilution (10⁻⁶). -4 10 -5 10 -6 100 μL of each strain was spread onto 2216E solid plates and incubated upside down at 30°C for 48 h. Single colonies with different colors, sizes, morphologies, and textures were picked using an inoculation loop and streaked onto 2216E plates to obtain single colonies. The purified strains were numbered and stored in a -20°C freezer with 25% glycerol. The colony morphology of each strain on 2216E plates and the cell morphology under SEM are shown below. Figure 1 As shown.

[0021] II. Molecular biological identification of the strain This invention screened three bacterial strains, NI-8, NI-11, and W-1, from biofilm and water samples of a Litopenaeus vannamei marine aquaculture system in Dongying. Genomic DNA was extracted from these strains using the TIANamp bacterial genomic DNA extraction kit (Tiangen Biotech, Beijing). The 16S rRNA gene sequence was amplified using universal primers 27F and 1492R, and the amplified products were sent to Beijing Qingke Biotechnology Co., Ltd. for sequencing. The sequences of the three strains are shown in SEQ ID NO. 1-3, respectively. Homology comparison analysis was performed between the obtained sequences and known 16S rRNA gene sequences in the NCBI database.

[0022] Phylogenetic trees constructed based on 16S rRNA gene sequences (e.g.) Figure 2 As shown in the figure, strains NI-8, NI-11, and W-1 exhibit different phylogenetic relationships. NI-8 is more closely related to NI-11, while W-1 is relatively more distantly related to both. Homology comparison of 16S rRNA sequences reveals that NI-8 and... Tritonibacter mobilis strain A09D-002 showed the highest similarity (100%), hence it was named *Tritonella motilityis*. Tritonibacter mobilis ;NI-11 and Paracoccus homiensis strain UNIMAS AA-M02 showed the highest similarity (99.93%), hence the name *Paracococcus capensis*. Paracoccus homiensis W-1 was identified as GlutamicibacterMember of the genus, named Bacillus glutamicum. Glutamicibacter sp.

[0023] The above three strains were deposited at the China General Microbiological Culture Collection Center on April 13, 2026, as *Tritonella motilityis*. Tritonibacter mobilis The accession number is CGMCC No. 38221; Bacillus glutamate Glutamicibacter sp. accession number is CGMCC No. 38222; *Paragonimus westermani* Paracoccus homiensis The accession number is CGMCC No. 38223. The address of the depositary is: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0024] III. Functional determination of strains 1. Evaluation of heterotrophic nitrification-aerobic denitrification performance of the strain: A single strain suspension (OD600 = 0.6) in the logarithmic growth phase was inoculated into sterilized nitrification medium NM at an inoculum rate of 1% (v / v) and cultured at 160 rpm and 30°C for 48 hours. The NH4+ content in the supernatant was measured. + -N, NO2 - -N and NO3 - The content of -N. NH4 + -N, NO2 - -N and NO3 - The concentration of -N was determined according to the standard method. Among them, NH4... + The concentration of NO2- was determined using the salicylic acid spectrophotometric method. - -N concentration was determined using the naphthylethylenediamine spectrophotometric method, and nitrate concentration was determined using the zinc-cadmium reduction method. Results showed... P. homiensis NI-11 and Glutamicibacter sp. W-1 exhibits excellent heterotrophic nitrification-aerobic reaction performance, effectively controlling total ammonia nitrogen (TAN) and nitrite (NO2). - -N) and nitrates (NO3) - The removal rates of -N were all above 90% (Table 1).

[0025] Table 1. Nitrification and denitrification performance of the three strains .

[0026] 2. Evaluation of bacterial colonization ability: A suspension of a single bacterial strain in the logarithmic growth phase (OD200) was prepared. 600= 0.6) was diluted 1:3 with fresh sterile 2216E medium, and 200 μL of this diluted bacterial suspension was inoculated into a 96-well plate. After incubation at 30°C for 72 h, the culture was washed twice with 250 μL of sterile physiological saline, dried, and fixed at 60°C for 30 min. Then, 200 μL of 0.1% crystal violet solution was added to each well for staining for 5 min, washed three times with physiological saline, and dried at 60°C for 10 min. Finally, 200 μL of 33% glacial acetic acid was added to each well for incubation for 5 min, and the OD value was recorded at 630 nm. The biofilm formation ability was evaluated by comparing the OD value with the control group. 2 mL of the logarithmic phase bacterial suspension (OD) was taken. 600 = 0.6) Transfer to a test tube and let stand for observation. Take a sample from the top of the test tube at intervals to measure the OD. 600 Value. The auto-aggregation rate of the strain is calculated using the following formula: At and A0 represent the OD at time t and 0, respectively. 600 Value. Tritonibacter mobilis NI-8 was mixed with the two bacterial strains mentioned above at a 1:1 ratio and incubated at 30°C for 24 h. The biofilm formation and self-aggregation abilities of the co-cultured bacterial solutions were then determined using the same method. The results are shown in Table 2. Tritonibacter mobilis NI-8 possesses strong biofilm formation and self-aggregation capabilities, and when co-cultured with two other strains, it also induces the cultures to exhibit strong biofilm formation and self-aggregation capabilities.

[0027] Table 2 Tritonibacter mobilis Colonization ability of NI-8 strain and its co-culture with other strains .

[0028] IV. Construction of synthetic microbial communities and evaluation of nitrogen degradation and biofilm formation capabilities. Will Tritonibacter mobilis NI-8 P. homiensis NI-11 and Glutamicibacter Synthetic bacterial cultures of sp. W-1 were mixed in equal volumes to form different combinations to construct synthetic bacterial communities. A final volume of 5 mL of the synthetic community was inoculated into 95 mL of NM medium and incubated at 160 r / min and 30℃ for 24 h. The nitrogen removal efficiency was then assessed using the methods described above. The synthetic community composed of three strains exhibited a higher biofilm formation capacity, reaching 30.47 ± 0.76. Its total nitrogen removal efficiency in NM medium reached 99.85 ± 0.20 (Table 3).

[0029] Table 3. Nitrogen removal efficiency and biofilm formation capacity of different bacterial combinations .

[0030] Given the excellent performance of the three-strain bacterial combination in total nitrogen removal efficiency, the removal effects of single-strain bacteria and the synthetic bacterial group composed of three strains on different types of nitrogen compounds were tested. The results are as follows: Figure 3 As shown, strain NI-11 showed resistance to NH4+ within 36 hours of culture. + -N, NO2 - -N and NO3 - Strain W-1 showed good removal efficiency for NO2, achieving removal rates of 88.90%, 97.49%, and 91.88%, respectively. - -N and NO3 - The removal rates of -N reached 99.80% and 96.01%, respectively, for NH4+. + The removal rate of -N was slightly lower, at 71.22%. Strain NI-8 showed a slightly lower removal rate for NH4+. + The removal rate of -N was 76.62%, and the removal rate of NO2 was [missing information]. - -N and NO3 - The removal rates of -N were relatively low, at only 29.08% and 48.59%. Compared to single strains, the synthetic microbial community achieved NO2 removal in a shorter time. - -N and NO3 - Highly efficient removal of -N, especially for NH4+ + -N, NO2 - -N and NO3 - The removal rates of -N reached 98.58%, 99.87% and 96.95% respectively, showing good removal effects on nitrogen in different states.

[0031] V. Analysis of Co-culture of Three Strains Based on the different colony morphologies of these three strains, a co-culture experiment was conducted, and the results are shown below. Figure 4 The growth curves, number, and distribution of each strain during the culture of the constructed synthetic microbial community were measured. The results showed that the total colony count in the mixed culture reached 2 × 10⁻⁶ after approximately 12 hours. 9 CFU / mL, followed by a slight increase in colony count over the next 12-60 hours, but generally remaining around 10. 9 This is on the order of magnitude, which is similar to the OD of the mixed bacterial culture. 600 The values ​​change in a consistent manner.

[0032] The relative abundance changes of the three strains in the mixed bacterial culture were analyzed. Initially, strain W-1 had a higher proportion, around 70%, while strains NI-8 and NI-11 accounted for approximately 20% and 9%, respectively. With increasing culture time, strain NI-8 gradually became the dominant strain in the system, reaching a relative abundance of 70%–80%, which may be related to its strong biofilm-forming ability. The relative abundance of strain W-1 remained stable at around 20%, while strain NI-11 had the lowest relative abundance, at 3%–4%. No obvious antagonistic phenomenon was observed during the co-culture of the three strains. Therefore, the mixed culture of NI-8, NI-11, and W-1 can be considered a stable HN-AD community.

[0033] VI. Bioenhancing Effect of Synthetic Microbial Community in Moving Bed Biofilm Reactor (MBBR) for Seawater Aquaculture Will T. mobilis NI-8 P. homiensis NI-11 and G. sp. W-1 was inoculated into sterile 2216E medium and cultured at 30°C with shaking at 160 r / min until the logarithmic growth phase. The OD values ​​of each bacterial suspension were then adjusted using fresh sterile 2216E medium. 600 With a value of 0.6, equal volumes of various bacterial suspensions were mixed to prepare seed cultures of different combinations of synthetic bacterial communities. Six moving bed biofilm reactors were filled with 30% K5 carrier. The MBBR device and K5 carrier were as follows... Figure 5 As shown.

[0034] Each reactor was pre-inoculated with activated sludge (3000 mg / L) from the aerobic tanks of a marine aquaculture farm. The reactors were initially operated for 5 days in marine aquaculture wastewater. Aerators were used to control the dissolved oxygen concentration at 5.5–6.5 mg / L, and a thermostat was used to control the reactor temperature at 25.0 ± 1.0℃. MBBR1 was not inoculated with any bacteria; MBBR2 was inoculated with NI-8+NI-11+W-1; MBBR3 with NI-8+NI-11; MBBR4 with NI-8+W-1; MBBR5 with NI-11; and MBBR6 with W-1. Effluent quality was periodically monitored, and the start-up status of the different moving bed biofilm reactors was assessed. Results are as follows: Figure 6 As shown. NH4 in each reactor. + -N concentrations decreased slowly, approaching 0 mg / L in the later stages of startup. The MBBR2 reactor inoculated with a synthetic bacterial community composed of three strains showed the best denitrification effect, with effluent NO2 levels decreasing after approximately 15 days. - The nitrogen concentration was below 1 mg / L, approximately 10 days earlier than MBBR1, and its NO2 concentration was also lower. - -N removal rate reached 99.6%, demonstrating rapid start-up of nitrogen removal capacity. MBBR1 without inoculation of bacterial colonies showed reduced NO2 in the effluent during the later stages of start-up.- The nitrogen concentration was approximately 2.5 mg / L, but NO3... - Nitrogen accumulation was severe, exceeding 10 mg / L. No NO3 was observed during the start-up of the MBBR2 reactor inoculated with three strains of bacteria. - Nitrogen accumulation. A combination of a denitrifying strain (W-1 / NI-11) and a bridging bacterium (NI-8) (MBBR3 and MBBR4), while showing good denitrification efficiency, still resulted in NO3 accumulation. - A small accumulation of nitrogen was observed. Although the MBBR5 and MBBR6 reactors, inoculated only with denitrifying strains W-1 or NI-11, initially achieved NO2 accumulation... - N is removed relatively quickly, but its stability is poor, and NO2 appears later. - N and NO3 - Fluctuations and accumulation of nitrogen (N). It is evident that a proper combination of denitrifying and bridging bacteria is key to achieving rapid start-up and stable operation of the MBBR reactor.

[0035] After a 100-day continuous start-up experiment, the MBBR1 and MBBR2 reactors underwent a 30-day monitoring period in the effluent from seawater aquaculture, with results largely consistent with those observed after 100 days of start-up. The two reactors also tested their performance against NH4+. + MBBR1 showed good removal efficiency for NO2-, with concentrations all below 0.5 mg / L. - -N removal efficiency is lower than MBBR2, and NO3 removal efficiency is lower. - High -N concentration. MBBR2, however, has a high concentration of NH4+. + -N, NO2 - -N and NO3 - -N both showed good removal effects.

[0036] VII. Biofilm Formation During the Start-up Phase of a Moving Bed Biofilm Reactor (MBBR) for Seawater Aquaculture In a moving bed biofilm reactor (MBBR), the formation rate and thickness of the biofilm on the carrier reflect, to some extent, the colonization rate and colonization amount of microorganisms in the reactor. Analysis of the biofilm on the carriers in MBBR1 and MBBR2 revealed that, with increasing operating time, the carrier morphology gradually changed from white to orange-yellow and then further to yellowish-brown. Faster microbial attachment was observed in MBBR2, and this difference in carrier morphology persisted until approximately day 41. Figure 7 ).

[0037] VIII. Nitrogen Removal Capacity of Moving Bed Biofilm Reactor (MBBR) after Start-up To test the simultaneous nitrification-denitrification (SND) efficiency of the reactor, NH4+ at a concentration of 20 mg / L was used. +Experiments were conducted using -N to replace the original seawater aquaculture wastewater in the synthetic moving bed biofilm reactor, and NH4 was detected in the effluent. + -N, NO2 - -N and NO3 - -N. All other conditions remained consistent with the experimental conditions described above. The calculation method for the simultaneous nitrification-denitrification (SND) efficiency when ammonium sulfate was the sole nitrogen source is as follows: ; in, and These represent the concentrations of nitrite nitrogen and nitrate nitrogen in the effluent, respectively. and These represent the ammonia nitrogen concentrations in the influent and effluent, respectively.

[0038] The results showed that the MBBR1 and MBBR2 reactors had a 24-hour effect on NH4+. + The removal rates of -N were all greater than 90%, with no significant difference. However, there was a highly significant difference in SND efficiency between the two groups. The average SND efficiency of MBBR2 was 69.01%, which was significantly higher than that of MBBR1 (34.26%) (Table 4).

[0039] Table 4. Simultaneous nitrification and denitrification capacity of synthetic microbial community-enhanced moving bed biofilm reactor (MBBR) .

Claims

1. A strain suitable for denitrification treatment in high-salinity water bodies, characterized in that: The strain is *Tritonella motilityis*. Tritonibacter mobilis It was deposited on April 13, 2026 at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 38221.

2. A strain suitable for denitrification treatment in high-salinity water bodies, characterized in that: The strain is Bacillus glutamate. Glutamicibacter sp. It was deposited on April 13, 2026 at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 38222.

3. A strain suitable for denitrification treatment in high-salinity water bodies, characterized in that: The strain is *Paracococcus faecium*. Paracoccus homiensis It was deposited at the China General Microbiological Culture Collection Center (CGMCC) on April 13, 2026, with accession number CGMCC No. 38223.

4. A biological composition suitable for denitrification treatment of high-salinity water bodies, characterized in that: Triton's motility as described in claim 1 Tritonibacter mobilis The glutamate bacillus according to claim 2 Glutamicibacter sp. And the Cape Paracoccus as described in claim 3 Paracoccus homiensis composition.

5. The use of the biological composition according to claim 4, characterized in that: This biological composition is used to prepare microbial agents for the treatment of recirculating aquaculture water and tailwater in marine aquaculture.

6. A bacterial agent suitable for denitrification treatment in high-salinity water bodies, characterized in that: The microbial agent contains the biological composition of claim 4.

7. A method for denitrification treatment of high-salinity water, characterized in that: The biological composition of claim 4 or the bacterial agent of claim 6 is inoculated into the water body to be treated.

8. The method according to claim 7, characterized in that: The biological composition of claim 4 or the bacterial agent of claim 6 is inoculated into a seawater moving bed biofilm reactor in the water to be treated.

Images