Aerobic denitrifying halomonas tianzhou LHT6 and application of aerobic denitrifying halomonas tianzhou LHT6

Abstract

The invention relates to an aerobic denitrification halomonas tianxiuensis LHT6, the preservation number of which is CGMCC No.32312. The strain can tolerate salinity, heavy metal ions and antibiotic stress under the condition of low carbon nitrogen ratio to realize efficient denitrification, and has application significance in actual treatment of water bodies such as aquaculture wastewater and pharmaceutical wastewater.

Description

Technical Field

[0001] The invention relates to aerobic denitrifying Halomonas LHT6 and application thereof. Background Art

[0002] Nitrogen pollution is an important environmental issue in contemporary times. Excessive nitrogen emissions can cause black and smelly water bodies and eutrophication, seriously endangering ecological balance and human health. At the same time, due to the construction and maintenance of urban sewage pipe networks, the water quality of the sewage treatment system inlet water shows the characteristics of a low carbon-nitrogen ratio. The lack of carbon sources restricts the removal of nitrogen in water bodies; at the same time, natural water bodies also have low carbon-nitrogen ratio characteristics because carbon sources cannot be added. Therefore, under the background of dual carbon (carbon peak and carbon neutrality), in order to achieve carbon emission reduction, less carbon source addition and the development of new biological denitrification technologies suitable for low carbon-nitrogen ratio water bodies are the general trend of sewage treatment plant development. The emergence of aerobic denitrification and the separation of aerobic denitrifying bacteria have broken the limitation that traditional biological denitrification technology needs to be carried out in the same reactor, and has been widely used in biological denitrification.

[0003] In addition, with the continuous development of aquaculture, pharmaceutical industry, etc., a large amount of wastewater is generated. This type of wastewater not only contains a large amount of nitrogen, but also contains high salinity and different types of antibiotics. Studies have shown that the presence of salinity will inhibit cell growth, cause an imbalance in the osmotic pressure inside and outside the cell, and lead to cell dehydration or even death; it will also change the nitrogen metabolism pathway of denitrifying bacteria and reduce the expression of denitrification genes. The broad antibacterial spectrum of antibiotics will kill or inhibit the growth and reproduction of microorganisms, and will also inhibit the metabolic activity and enzyme activity of cells. At the same time, some saline wastewater also contains heavy metal ions, such as Zn (II), Cu (II), Mn (II) and Fe (II). The presence of heavy metal ions usually has a toxic effect on microorganisms and even causes the direct death of microorganisms. These factors also restrict the denitrification efficiency of this type of water body, which in turn affects the sewage treatment effect.

[0004] Therefore, screening out aerobic denitrifying bacteria that can tolerate salinity, heavy metal ion and antibiotic stress and achieve efficient nitrogen removal under low carbon-nitrogen ratio conditions has application significance in the actual treatment of aquaculture wastewater, pharmaceutical wastewater and other water bodies. Summary of the invention

[0005] The present invention aims to provide a kind of Halomonas LHT6 which can tolerate salinity, heavy metal ion and antibiotic stress and realize efficient denitrification under low carbon-nitrogen ratio conditions and its application.

[0006] The present invention adopts the following technical solution: An aerobic denitrifying bacterium Halomonas tianxiuensis) LHT6, whose deposit number is CGMCC No.32312. The strain was deposited on October 23, 2024 at the General Microbiology Center of China Microbiological Culture Collection Administration, with the address in Beijing, China.

[0007] Furthermore, the Halomonas truncatula LHT6 can perform aerobic denitrification.

[0008] Furthermore, the Halomonas LHT6 can denitrify under the condition of C / N of 2-10.

[0009] In particular, the Halomonas sp. LHT6 can efficiently denitrify under the condition of C / N of 4.

[0010] Furthermore, the Halomonas truncatula LHT6 can grow and remove nitrate under pH conditions of 7 to 11.

[0011] In particular, the Halomonas sp. LHT6 can grow and remove nitrate at a pH of 10.

[0012] Furthermore, the Halomonas truncatula LHT6 can grow and remove nitrates under conditions containing 0% to 15% NaCl.

[0013] In particular, the Halomonas sp. LHT6 can grow and remove nitrate under the condition of 15% NaCl.

[0014] Furthermore, the Halomonas truncatula LHT6 may be resistant to oxacillin, cefuroxime sodium, streptomycin, lincomycin, vancomycin, polymyxin B, cotrimoxazole, clindamycin, doxycycline and metronidazole.

[0015] Furthermore, the Halomonas sp. LHT6 can grow and remove nitrate under conditions containing Zn (II) ions, Cu (II) ions, Mn (II) ions and / or Fe (II) ions.

[0016] An application of the above-mentioned Halomonas LHT6 in sewage treatment.

[0017] An application of the above-mentioned Halomonas LHT6 in treating aquaculture wastewater or pharmaceutical wastewater containing salt, antibiotics and / or heavy metal ions under low carbon-nitrogen ratio conditions.

[0018] A sewage treatment agent comprising the above-mentioned Halomonas truncatula LHT6.

[0019] The beneficial effects of the present invention are as follows: the Halomonas LHT6 of the present invention has excellent salt resistance, heavy metal resistance, alkali resistance, and antibiotic resistance. Especially under the condition of C / N of 4, it can still carry out aerobic denitrification and achieve efficient denitrification in harsh environments. It has application significance in the actual treatment of water bodies such as aquaculture wastewater and pharmaceutical wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a scanning electron micrograph of strain LHT6.

[0021] Figure 2 This is the phylogenetic tree of strain LHT6.

[0022] Figure 3 The denitrification characteristics of strain LHT6 under different carbon-nitrogen ratios.

[0023] Figure 4 The denitrification characteristics of strain LHT6 under different carbon source conditions.

[0024] Figure 5 NO3 in strain LHT6 under different pH - -N and TDN removal rates.

[0025] Figure 6 NO3 of strain LHT6 under the influence of different rotation speeds - -N and TDN removal rates.

[0026] Figure 7 This is a picture of the plate results of the drug sensitivity test for strain LHT6.

[0027] Figure 8 The strain LHT6 was affected by different concentrations of sulfamethoxazole under the influence of NO3 - -N and TDN removal rates.

[0028] Fig. 9 NO3 in strain LHT6 under the influence of different concentrations of tetracycline - -N and TDN removal rates.

[0029] Fig.10 The denitrification performance of strain LHT6 under different salinities.

[0030] Fig.11 This is the nitrate nitrogen removal ability of strain LHT6 under the influence of different concentrations of heavy metals. DETAILED DESCRIPTION

[0031] Example 1 Isolation and screening of LHT6 10mL of fresh activated sludge sample from a pharmaceutical wastewater treatment plant in Shijiazhuang was added to a 250mL conical flask containing 100mL of enrichment medium (LB medium) for enrichment culture. The culture conditions were 25℃ and 120rpm. The medium was replaced every 2 days for a total of 4 days. After the culture, the mixed solution (7.5mL) was taken to a 250mL conical flask containing 150mL of denitrification medium, and cultured at 25℃ and 120rpm. The pharmaceutical wastewater and denitrification medium were prepared according to the ratio (v / v) of 0 / 10, 1 / 9, 2 / 8, 3 / 7, 4 / 6, 5 / 5, 6 / 4, 7 / 3, and 8 / 2 to prepare the acclimation medium. Each concentration of the medium was cultured for 3 days and repeated twice. The acclimation process took about 54 days.

[0032] Take 1 mL of the bacterial suspension after acclimation and add it to 9 mL of buffer. -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 , 10 -6 Serial dilutions were performed from 10 -6 Take 0.2mL of the mixed solution of 100% concentration and transfer it to the solid denitrification medium. Use a sterile spreader stick after high pressure sterilization to evenly spread the bacterial solution on the agar plate, seal it and invert it at 25℃ to culture at a constant temperature until colonies are visible to the naked eye. Use a sterile inoculation loop that has been burned by an alcohol lamp and cooled to pick colonies of different shapes and sizes and streak them on the agar plate. After isolating a single colony, streak it several times to obtain a purified single bacteria, and store it in a 4℃ refrigerator for screening.

[0033] The isolated single colonies were inoculated into 100 mL of LB medium for enrichment culture for 2 days. After the culture, the bacterial mixture was centrifuged at 6000 r / min, the obtained bacteria were shaken with buffer and 10 mL was inoculated into a 250 mL conical flask containing 150 mL of fresh denitrification medium. The denitrification ability was identified and single bacteria with a nitrate nitrogen removal rate of more than 90% were screened out. The denitrification efficiency was verified again for at least 3 times, and the single strain LHT6 with a nitrate nitrogen removal rate of more than 90% was screened out.

[0034] The specific components of each of the above culture media include: LB medium: tryptone 10 g / L, yeast extract powder 5 g / L, NaCl 10 g / L, sterilize at 121°C for 30 min.

[0035] Denitrification medium: CH3COONa 4.69 g / L, KNO3 0.722 g / L, Wei's salt solution (including K2HPO4·3H2O 0.75 g / L, NaH2PO4·2H2O 0.25 g / L, NaCl 0.12 g / L, MnSO4·H2O 0.01 g / L, MgSO4·7H2O 0.05 g / L, FeSO4·7H2O 0.01 g / L), high pressure sterilization at 121°C for 30 min.

[0036] Solid denitrification medium: CH3COONa 4.69g / L, KNO3 0.722g / L, K2HPO4·3H2O 0.75g / L, NaH2PO4·2H2O 0.25g / L, NaCl 0.12g / L, MnSO4·H2O 0.01g / L, MgSO4·7H2O 0.05g / L, FeSO4·7H2O 0.01g / L, agar 20g / L, high pressure sterilization at 121℃ for 30min.

[0037] Buffer: NaCl 8g / L, KCl 0.2g / L, Na2HPO4·12H2O 3.63g / L, KH2PO4 0.24g / L, adjust pH to 7.4.

[0038] Example 2 Morphological and molecular identification of LHT6 Electron microscopic observation of strain LHT6 showed that the cells had a rod-shaped appearance (e.g. Figure 1 The genomic DNA of the strain was extracted, and the PCR product was amplified using the universal primers 27F / 1492R for bacterial 16S rRNA gene amplification, and sent to Shanghai Meiji Biopharmaceutical Technology Co., Ltd. for sequence sequencing. The sequencing results (shown as SEQ ID No. 1) were compared and analyzed in the NCBI database to identify their species relationship, and it was found that strain LHT6 was Halomonas tianxiuensis With high similarity, the phylogenetic tree of strain LHT6 was constructed using MEGA (11.0). Figure 2 shown.

[0039] Based on the above analysis, strain LHT6 was identified as: Halomonas tianxiuensis ( Halomonas tianxiuensis ). The strain was deposited at the General Microbiology Center of China Microbiological Culture Collection Administration on October 23, 2024, at the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, with the deposit number CGMCC No. 32312.

[0040] Example 3 Effect of different C / N ratios on aerobic denitrification characteristics of strain LHT6 The activated seed liquid of strain LHT6 was inoculated into denitrification medium with C / N of 2, 4, 6, 8, and 10 at a 5% inoculum rate (the KNO3 content was fixed, the carbon-nitrogen ratio was controlled by changing the CH3COONa content, and the other components of the medium were the same as those in Example 1), and cultured at 25°C and 120rpm for 72 h. Samples were taken at 0 h, 12 h, 24 h, 36 h, 48 h, 60 h, and 72 h to measure OD 600 , nitrate nitrogen (NO3 - -N), ammonia nitrogen (NH4 + -N), nitrite nitrogen (NO2 - -N) and total dissolved nitrogen (TDN).

[0041] The results are as follows Figure 3 As shown in the figure, strain LHT6 can achieve efficient denitrification when C / N is 2, 4, 6, 8 and 10, and the removal rates of TDN are 98.85%, 98.15%, 97.14%, 97.25% and 98.17% respectively. When C / N is 4, 6, 8, the denitrification rate of the strain is higher than that when C / N is 2 and 10. Combined with the requirements of energy-saving and efficient nitrogen reduction under the "dual carbon background", C / N of 4 is selected as the optimal carbon-nitrogen ratio of the strain.

[0042] Denitrification medium (C / N=4): CH3COONa 1.3667 g / L, KNO3 0.722 g / L, Wei's salt solution (including K2HPO4·3H2O 0.75 g / L, NaH2PO4·2H2O 0.25 g / L, NaCl 0.12 g / L, MnSO4·H2O 0.01 g / L, MgSO4·7H2O 0.05 g / L, FeSO4·7H2O 0.01 g / L), pH 7.5, high pressure sterilization at 121℃ for 30 min.

[0043] Example 4 Effects of different carbon sources on aerobic denitrification characteristics of strain LHT6 After changing the C / N ratio, the activated seed solution of strain LHT6 was inoculated into fresh denitrification medium at a 5% inoculum rate (the C / N ratio was determined to be 4, and the medium formula was consistent with Example 3 except for changing the carbon source type), and cultured at 25°C and 120 rpm for 72 h. Samples were taken at 0 h, 12 h, 24 h, 36 h, 48 h, 60 h, and 72 h to measure the OD 600 , nitrate nitrogen, ammonia nitrogen, nitrite nitrogen and total dissolved nitrogen.

[0044] The results are as follows Figure 4As shown in the figure, when sodium acetate was used as the sole carbon source, the removal rates of nitrate nitrogen and dissolved total nitrogen were 92.88% and 92.66% in 72 hours, respectively, which were significantly higher than the removal rates when sodium succinate, sodium citrate and sucrose were used as the sole carbon source. When sodium succinate, sodium citrate and sucrose were used as the sole carbon source, the removal efficiency of the strain was low and accompanied by the accumulation of nitrite nitrogen, especially when sodium succinate was used as the carbon source, the removal rates of nitrate nitrogen and dissolved total nitrogen of the strain were only 22.03% and 14.53%. Therefore, sodium acetate was selected as the best single carbon source for strain LHT6.

[0045] Sodium acetate was determined as the single carbon source, and the composition of the denitrification culture medium in subsequent experiments was: CH3COONa 1.3667 g / L, KNO3 0.722 g / L, Wei's salt solution (including K2HPO4·3H2O 0.75 g / L, NaH2PO4·2H2O 0.25 g / L, NaCl 0.12 g / L, MnSO4·H2O 0.01 g / L, MgSO4·7H2O 0.05 g / L, FeSO4·7H2O 0.01 g / L), pH 7.5, and high-pressure sterilization at 121°C for 30 min.

[0046] Example 5 Effect of different pH values ​​on aerobic denitrification characteristics of strain LHT6 The activated cell mixture of strain LHT6 was inoculated into fresh denitrification medium (the medium composition was the same as in Example 4) at a 5% inoculum, and cultured at 25°C and 120 rpm for 120 h. Samples were taken at 24 h, 48 h, 72 h and 120 h to measure OD. 600 , nitrate nitrogen, ammonia nitrogen, nitrite nitrogen and total dissolved nitrogen.

[0047] The results are as follows Figure 5 As shown in the figure, the denitrification efficiency of strain LHT6 under different pH conditions is significantly different. When the pH is 5, 6 and 12, the strain can hardly remove nitrogen; when the pH is 7-11, strain LHT6 can remove more than 90% of nitrate nitrogen and there is no accumulation of nitrite nitrogen. Among them, the growth and nitrogen removal rate of the strain are the fastest at pH 10, and 96.97% of nitrate nitrogen can be removed in 24 hours, with a small amount of nitrite nitrogen accumulation (3.76 mg / L), and all nitrogen can be removed in 48 hours (the removal rate of dissolved total nitrogen is 98.26%). Therefore, strain LHT6 can grow and efficiently remove nitrate at pH 7-11, indicating that the strain is suitable for survival in an alkaline environment, with the optimal pH being 10.

[0048] Example 6 Denitrification characteristics of strain LHT6 under the influence of different rotation speeds The activated cell mixture was inoculated into fresh denitrification medium (the medium formula is the same as in Example 4) at a 5% inoculum amount, and the rotation speed was set to 0, 40, 80, 120, 160, and 200 rpm respectively. The culture was cultured at 25°C for 72 h, and samples were taken every 12 h to measure the OD 600 , nitrate nitrogen, ammonia nitrogen, nitrite nitrogen and total dissolved nitrogen.

[0049] The results are as follows Figure 6 As shown in the figure, strain LHT6 can efficiently remove nitrate under different speed conditions. When the speed is 0rpm, the growth and denitrification rate of the strain are slow, and the nitrogen removal rate reaches more than 90% after 48h of reaction. When the speed is 40-200rpm, it can be found that the nitrogen removal rate of the strain reaches more than 90% after 24h, and the speed is the highest during the reaction process. The faster the growth and denitrification rate of the strain, this is also related to the dissolved oxygen (DO) matched by different speeds. Therefore, for strain LHT6, when the speed is not less than 120rpm, the strain can grow rapidly and have a higher denitrification efficiency.

[0050] Example 7 Drug sensitivity test of strain LHT6 The paper diffusion method was used to test the drug sensitivity of strain LHT6. Take 0.2 mL of the mixed bacterial solution cultured in the denitrification medium for 24 hours and evenly spread it on the surface of the LB solid medium. The plate was placed on the clean bench for 2-3 minutes until the bacterial solution dried. Use sterile tweezers to take the drug sensitivity paper and stick it on the surface of the plate and gently press the paper to make it fit tightly. Then place it in a 35°C constant temperature incubator for 18-24 hours. Three parallel samples were set for each experiment.

[0051] After the culture is completed, the diameter of the inhibition zone is measured with a caliper and the results are judged according to the antibiotic sensitivity standards of the Clinical Laboratory Standards Institute (CLSI). Figure 7 The results of the antibiotic resistance experiment are shown in Table 1. According to the performance of the strain in the resistance test, it can be used as an indicator organism in aquaculture.

[0052] Table 1 Results of drug sensitivity test of strain LHT6 .

[0053] Example 8 Denitrification characteristics of strain LHT6 under the influence of different concentrations of sulfamethoxazole (sulfonamide antibiotics) According to the performance of the strain in Example 7, sulfamethoxazole, which showed drug resistance in the drug resistance experiment and was widely used in practice, was selected. The activated seed solution of strain LHT6 was inoculated into fresh denitrification medium containing different concentrations of sulfamethoxazole (0, 50, 100, 250, 500, 1000 μg / L) at a 5% inoculation rate (the composition of the denitrification medium was consistent with that in Example 4), and cultured at 25°C and 120rpm under constant temperature shaking conditions, and samples were taken regularly to determine nitrate nitrogen, ammonia nitrogen, nitrite nitrogen and dissolved total nitrogen.

[0054] like Figure 8 As shown in the figure, after adding different concentrations of sulfamethoxazole to the denitrification culture, strain LHT6 removed almost all nitrogen at 48h (removal rate reached more than 99%). A small amount of nitrite accumulated during the reaction, but it was finally completely removed. These results show that strain LHT6 can tolerate the influence of sulfamethoxazole in the range of 1000μg / L and has good denitrification performance. It can be applied to antibiotic wastewater treatment to achieve efficient denitrification.

[0055] Example 9 Denitrification characteristics of strain LHT6 under the influence of different concentrations of tetracycline (tetracycline antibiotics) According to the performance of the strain in Example 7, tetracycline was selected, which showed sensitive characteristics in the drug resistance experiment and was frequently detected in the sewage treatment system. The activated seed solution of strain LHT6 was inoculated into fresh denitrification medium containing different concentrations of tetracycline (0, 50, 100, 250, 500 μg / L) at a 5% inoculum (the composition of the denitrification medium was consistent with that in Example 4), and cultured at 25°C and 120rpm under constant temperature shaking conditions. Samples were taken every 24 hours to determine nitrate nitrogen, ammonia nitrogen, nitrite nitrogen and dissolved total nitrogen.

[0056] The results are as follows Fig. 9 As shown in the figure, when different concentrations of tetracycline were added to the denitrification medium, the removal rate of nitrate by strain LHT6 could reach more than 95% at 144h; the removal efficiency was the highest when tetracycline was not added, and the removal rates of nitrate nitrogen and dissolved total nitrogen within 48h could reach 97.77% and 97.33%, respectively. Among them, the denitrification rate of strain LHT6 decreased with the increase of tetracycline concentration in the medium. Compared with the case without tetracycline, strain LHT6 could completely remove all nitrogen at 144h when 500μg / L tetracycline was added. It can be seen that although the strain was sensitive to tetracycline in the drug sensitivity test, the strain can still tolerate tetracycline within a certain concentration range and can be applied to wastewater treatment containing sensitive antibiotics.

[0057] Example 10 Salt tolerance characteristics and mechanism analysis of strain LHT6 The activated seed culture liquid of strain LHT6 was inoculated into fresh denitrification culture medium with salinity (NaCl) of 0%, 3%, 5%, 8%, 10%, 12% and 15% (the culture medium formula is the same as that in Example 4) at a 5% inoculation amount, and cultured at a constant temperature and shaking at 25°C and 120rpm. Samples were taken at regular intervals to determine nitrate nitrogen, ammonia nitrogen, nitrite nitrogen and total dissolved nitrogen.

[0058] The results of denitrification effect of strain LHT6 under different salinity (0%~15%) are as follows Fig.10 As shown in the results, when C / N was 4, under the influence of 0%~12% salinity, strain LHT6 removed almost all nitrates at 36h, 3d, 5d, 9d, 18d and 35d respectively, and there was no accumulation of nitrite nitrogen; under the influence of 15% salinity, the removal rates of nitrate and total nitrogen of strain LHT6 were 95.55% and 82.38%, respectively, with a small amount of nitrite nitrogen accumulation (11.86mg / L). These results show that salinity has an inhibitory effect on the growth and denitrification effect of the strain. The higher the salinity, the longer the adaptation time required for the growth of the strain. However, the strain can grow and achieve nitrogen removal under salinity stress within 15% under the condition of C / N of 4, indicating that it has a wide range of salt tolerance.

[0059] Obtaining relevant salt-tolerance genes of strain LHT6 through whole genome analysis nha C. ect B. ots A. gd A. pro ABC, kdp system, trk system and bet B. The strain can relieve the stress of high salt environment on cells by taking in, synthesizing and accumulating small molecule compatible substances in the cell, mainly including ect B Synthesized tetrahydropyridine, ots A synthetic trehalose, gd A synthesized glutamate, pro Proline and bet B is involved in the synthesis of betaine. These genes can also act as osmoprotectants to help LHT6 cope with high salt environments. In addition, the strain can also resist high salt stress by transporting small molecules compatible substances within the cell, such as the kdp system and the trk system, which help the intracellular k + These mechanisms endow strain LHT6 with high salt tolerance potential and can be applied to actual saline wastewater treatment.

[0060] Example 11 Tolerance of strain LHT6 to different heavy metal ions The suspension of strain LHT6 in the logarithmic phase was inoculated into denitrification medium containing different concentrations of heavy metal ions Zn (II), Cu (II), Mn (II) and Fe (II) at a 5% inoculation rate. The denitrification medium without heavy metal ions was used as a blank control and cultured at 25°C and 120 rpm. The medium with Zn (II) ions was cultured for 72 hours, the medium with Cu (II) ions was cultured for 120 hours, and the medium with Mn (II) and Fe (II) ions was cultured for 24 hours. The nitrate nitrogen concentration in the culture medium was sampled regularly to analyze the tolerance of strain LHT6 to different types of heavy metal ions.

[0061] The results are as follows Fig.11 As shown in the results, with the increase of concentration, heavy metal ions Zn (II) and Cu (II) showed a certain inhibitory effect on the growth and nitrate removal performance of strain LHT6. When 50 mg / L Zn (II) and Cu (II) ions were added, the nitrate removal rate of strain LHT6 decreased from 87.07% and 91.12% to 25.64% and 29.29% at 72 h and 120 h, respectively, compared with no heavy metal ions. Mn (II) and Fe (II) ions within a certain concentration range showed a significant promoting effect on the denitrification efficiency of strain LHT6. When Mn (II) and Fe (II) ions were added to the culture medium for 24 h, the nitrate removal rate reached more than 95%; and when 100 mg / L Mn (II) and Fe (II) ions were added to the culture medium, the nitrate removal rate of strain LHT6 increased from 91.56% to 100%.

Claims

1. A type of Halomonas spp. Halomonas tianxiuensis ) LHT6, characterized in that, Its deposit number is CGMCC No.32312.

2. The Halomonas truncatula LHT6 according to claim 1, characterized in that It can carry out aerobic denitrification.

3. The Halomonas truncatula LHT6 according to claim 1, characterized in that It can denitrify under the condition of C / N of 2~10.

4. The Halomonas truncatula LHT6 according to claim 1, characterized in that It can grow and remove nitrate at pH 7-11.

5. The Halomonas truncatula LHT6 according to claim 1, characterized in that It can grow and remove nitrates in conditions containing 0%~15% NaCl.

6. The Halomonas truncatula LHT6 according to claim 1, characterized in that It is resistant to oxacillin, cefuroxime sodium, streptomycin, lincomycin, vancomycin, polymyxin B, cotrimoxazole, clindamycin, doxycycline and metronidazole.

7. The Halomonas truncatula LHT6 according to claim 1, characterized in that It can grow and remove nitrate in the presence of Zn(II) ions, Cu(II) ions, Mn(II) ions and / or Fe(II) ions.

8. Use of the Halomonas truncatula LHT6 as claimed in claim 1 in sewage treatment.

9. Use of the Halomonas truncatula LHT6 as claimed in claim 1 in treating aquaculture wastewater or pharmaceutical wastewater containing salt, antibiotics and / or heavy metal ions under low carbon-nitrogen ratio conditions.

10. A sewage treatment agent comprising the Halomonas truncatula LHT6 as claimed in claim 1.

Images