Acid-resistant heterotrophic nitrification-aerobic denitrification bacterium as well as application and screening method thereof

Abstract

The invention belongs to the technical field of microorganisms, and relates to an acid-resistant heterotrophic nitrification-aerobic denitrification bacterium and application thereof. The heterotrophic nitrification-aerobic denitrification bacterium is acinetobacter, the name of the heterotrophic nitrification-aerobic denitrification bacterium is acinetobacter HY24, the heterotrophic nitrification-aerobic denitrification bacterium is preserved in the China Center for Type Culture Collection, and the preservation number of the heterotrophic nitrification-aerobic denitrification bacterium is CCTCC NO: M20241231. The acinetobacter HY24 can be used for treating acidic wastewater containing a single nitrogen source or a mixed nitrogen source, can efficiently remove ammonia nitrogen and nitrate nitrogen in a water body, does not accumulate nitrite nitrogen, and has great application potential in the field of sewage treatment. The obtaining and screening method comprises the following steps: taking sludge of a municipal sewage treatment plant, adding the sludge into an enrichment liquid for culturing, taking supernate, screening and purifying the supernate by using a heterotrophic nitrifying bacteria screening solid culture medium and an aerobic denitrifying bacteria screening solid culture medium in sequence, and carrying out acid resistance screening by using culture mediums with different pH values, the steps are simple, and the operation is convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms and relates to acid-resistant heterotrophic nitrification-aerobic denitrification bacteria and an application and screening method thereof. Background Art

[0002] With the rapid development of the economy, water pollution in my country is becoming increasingly serious. A large amount of domestic sewage and industrial wastewater are discharged without being effectively treated, which has a great adverse impact on the ecological environment and biological health. The discharge of high-concentration inorganic nitrogen wastewater will cause a significant increase in the content of nitrogen compounds in the water body, causing serious environmental problems such as eutrophication of rivers and deterioration of water sources. In addition, ammonia nitrogen and nitrate nitrogen will be converted into nitrite nitrogen or nitrosamines under certain conditions, posing a threat to biological health. Therefore, such wastewater must be treated to meet the standards before being discharged.

[0003] Common methods for denitrification of wastewater are divided into physical, chemical and biological methods. Although the traditional biological method can remove nitrogen from water through biological metabolism (see Chinese patent CN111454857B), due to the different reaction conditions of autotrophic nitrification and anaerobic denitrification, it also costs a lot in terms of time and economy. Heterotrophic nitrification-aerobic denitrification microorganisms can remove nitrogen from wastewater by nitrification and denitrification reactions at the same time and in the same place. [2] However, most of them have good biological denitrification effects under neutral or weakly alkaline conditions, while the growth rate and enzyme activity of bacteria will be inhibited under acidic conditions. For some acidic wastewater, the denitrification effect of such strains is not obvious and the cost is high. Summary of the invention

[0004] The first technical problem to be solved by the present invention is to provide acid-resistant heterotrophic nitrification-aerobic denitrification bacteria: Acinetobacter HY24.

[0005] The second technical problem to be solved by the present invention is to provide the application of the above-mentioned acid-resistant heterotrophic nitrification-aerobic denitrification bacteria in the treatment of acidic wastewater containing a single nitrogen source or a mixed nitrogen source.

[0006] The third technical problem to be solved by the present invention is to provide a method for screening the above-mentioned acid-resistant heterotrophic nitrification-aerobic denitrification bacteria.

[0007] In order to solve the above technical problems, the present invention provides an acid-resistant heterotrophic nitrification-aerobic denitrification bacterium, the heterotrophic nitrification-aerobic denitrification bacterium is of the genus Acinetobacter, named Acinetobacter soli HY24, the preservation date is June 14, 2024, the preservation address is Wuhan, Wuhan University, China, and the preservation number of the collection in the China Center for Type Culture Collection is CCTCC NO: M20241231. And the use of the above Acinetobacter HY24 in the treatment of acidic wastewater containing a single nitrogen source or a mixed nitrogen source.

[0008] For the purpose of simple description, the acid-resistant heterotrophic nitrification-aerobic denitrification bacteria, i.e., Acinetobacter HY24, described in the present invention is hereinafter referred to as strain HY24.

[0009] The acquisition and screening of acid-resistant strains includes the following steps:

[0010] (1) 10 g of sludge from a municipal sewage treatment plant was added with 100 mL of enrichment liquid and incubated overnight at 30° C. and 200 rpm to obtain a mixed solution;

[0011] (2) taking 0.1 mL of the supernatant of the mixed solution obtained in step (1) for gradient dilution, and applying them respectively on a heterotrophic nitrification screening solid culture medium with a neutral pH, selecting single colonies with different morphologies and good growth for purification and culture, and finally screening out multiple strains of heterotrophic nitrifying bacteria after repeated screening and purification;

[0012] (3) selecting a single colony of heterotrophic nitrifying bacteria obtained in step (2) and inoculating it into a solid medium for screening aerobic denitrifying bacteria with a neutral pH, repeatedly screening and culturing for multiple times, selecting bacteria with good growth and storing them in 50% glycerol, precooling them in refrigerators at 4°C and -20°C for 30 minutes respectively, and finally storing them in a refrigerator at -80°C for long-term storage;

[0013] (4) The original strain stored in a -80°C refrigerator was inoculated into an 18×180 mm test tube containing 3 mL of aerobic denitrification medium at pH 5.5, and cultured at 30°C and 200 rpm for 24 h to confirm that the cell concentration was normal and the strain grew well;

[0014] (5) Take 200 uL of the bacterial solution obtained in step (4) and transfer it to an 18×180 mm test tube containing 3 mL of aerobic denitrification medium at pH 5.0, and culture it in a shaking incubator at 30° C. and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain grows well;

[0015] (6) Take 200 uL of the bacterial solution obtained in step (5) and transfer it to an 18×180 mm test tube containing 3 mL of aerobic denitrification medium at pH 4.5, and culture it in a shaking incubator at 30° C. and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain grows well;

[0016] (7) Take 80uL of the bacterial solution obtained in step (6), spread it on an aerobic denitrification solid medium, pick out single colonies with good growth, perform purification culture multiple times, obtain several strains with good growth, inoculate them into an aerobic denitrification medium with a pH of 4.5, and culture them in a shaking table at 30°C and 200rpm for 24h, then measure the nitrogen content in the fermentation liquid, and select the strain with the best denitrification effect for subsequent screening;

[0017] (8) The strain obtained in step (7) was gradually inoculated into an 18×180 mm test tube containing 3 mL of heterotrophic nitrification medium at pH 5.5, and cultured at 30° C. and 200 rpm for 24 h to confirm that the cell concentration was normal and the strain grew well;

[0018] (9) Take 200 uL of the bacterial solution obtained in step (8) and transfer it to an 18×180 mm test tube containing 3 mL of heterotrophic nitrification medium at pH 5.0. Incubate at 30°C and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain is growing well.

[0019] (10) Take 200 uL of the bacterial solution obtained in step (9) and transfer it to an 18×180 mm test tube containing 3 mL of heterotrophic nitrification medium at pH 4.5, and culture it in a shaking incubator at 30°C and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain is growing well;

[0020] (11) taking 80 uL of the bacterial solution obtained in step (10) in a heterotrophic nitrification medium at a pH of 4.5, spreading it on a heterotrophic nitrification solid medium, and picking out a single colony with good growth for purification and culture;

[0021] (12) The strain obtained in step (11) was inoculated into a heterotrophic nitrification medium with a pH of 4.5, and the nitrogen content in the fermentation broth was measured after culturing at 30° C. and 200 rpm on a shaker for 24 h to screen the strain with the best denitrification effect, that is, to screen out heterotrophic nitrification-aerobic denitrification bacteria with acid resistance;

[0022] The above culture media were all adjusted to pH with 1 mol / L sterile hydrochloric acid. Identification of strains: The total DNA of the strains obtained by repeated screening was extracted using a bacterial total DNA extraction kit, and the qualified DNA samples were sent to Shanghai Meiji Biomedical Technology Co., Ltd. for subsequent whole genome determination. The whole genome sequence of bacteria was used to identify and analyze microorganisms to determine the species of bacteria. It was identified as Acinetobacter soli, containing a linear chromosome, 3418311bp bases, a total of 3240 genes, and no plasmid structure. It was named Acinetobacter soliHY24, and the accession number in GenBank is CP151168.

[0023] Preservation of strains: Add sterile 50% glycerol and overnight cultured bacterial solution into a strain preservation tube at a ratio of 1:1. Mix the bacterial solution and glycerol in the preservation tube thoroughly, pre-cool in 4℃ and -20℃ refrigerators for 30 minutes respectively, and finally place in a -80℃ refrigerator for long-term preservation.

[0024] The culture medium formula used is as follows (the pH value of the following culture medium is adjusted with 1 mol / L sterile hydrochloric acid):

[0025] Enrichment medium (g / L): C4H4Na2O4 4.7g, KNO3 1g, NH4Cl 1g, KH2PO4 0.007g, K2HPO4 0.027g, MgSO4 0.005g, trace element solution 2ml, pH 7.0-7.5;

[0026] Heterotrophic nitrification medium (g / L, nitrogen content 100 mg / L): C6H5Na3O7 5.375, NH4Cl0.382, KH2PO40.007, K2HPO4 0.35, MgSO4 0.005, trace element solution 2mL, pH 4.5.

[0027] Aerobic denitrification medium (g / L, nitrogen content 100 mg / L): KNO3 0.7214, C6H5Na3O75.375, KH2PO40.007, K2HPO4 0.35, MgSO4 0.005, trace element solution 2mL, pH 4.5.

[0028] Synchronous heterotrophic nitrification-aerobic denitrification medium (g / L, nitrogen content is 100 mg / L): KNO3 0.3607, NH4Cl0.191, C6H5Na3O7 5.375, KH2PO4 0.007, K2HPO4 0.35, MgSO4 0.005, trace element solution 2mL, pH 4.5.

[0029] Trace element solution (g / L): EDTA 0.1g, ZnSO4 . 7H2O 0.0078g, CaCl2 0.011g, MnCl ˙ 4H2O0.008g, FeSO 4˙ 7H2O 0.01g, (NH4)6Mo7O 24 0.0021 g, CuSO 4˙ 5H2O0.0032g, COCl 2˙ 6H2O0.0032g.

[0030] Advantages of the present invention: The present invention provides an acid-resistant heterotrophic nitrification-aerobic denitrification bacteria:

[0031] Under acidic conditions (pH 4.5), ammonia nitrogen and nitrate nitrogen in water can be removed efficiently without nitrite nitrogen accumulation.

[0032] Under acidic conditions (pH 4.5), when nitrate nitrogen is the only nitrogen source, the nitrate nitrogen removal rate reaches 62%, and there is no ammonia nitrogen accumulation; when ammonia nitrogen is the only nitrogen source, the ammonia nitrogen removal rate reaches 100%, and there is no nitrate nitrogen accumulation.

[0033] Under acidic conditions (pH 4.5), it has good simultaneous nitrification and denitrification effects, with ammonium nitrogen and nitrate nitrogen removal rates reaching 84% and 75% respectively, no nitrite accumulation, and a COD removal rate of 94%.

[0034] Moreover, the steps of strain acquisition and screening are simple and the raw materials are easily available. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a correlation view of the ammonium and nitrate nitrogen concentrations, pH, and OD600 values ​​in the fermentation broth of strain HY24 during the heterotrophic nitrification stage.

[0036] Figure 2 This is a correlation view of the ammonium nitrogen and nitrate nitrogen concentrations, pH and OD600 values ​​in the fermentation broth of strain HY24 during the aerobic denitrification stage.

[0037] Figure 3 It is a correlation view of pH and OD600 values ​​as well as ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, TN and COD concentrations in the fermentation broth of strain HY24 under simultaneous nitrification and denitrification. DETAILED DESCRIPTION

[0038] The acquisition and screening of acid-resistant strains includes the following steps:

[0039] (1) 10 g of sludge from the Chengnan Wastewater Treatment Plant in Wuhu City was added with 100 mL of enrichment liquid and incubated overnight at 30°C and 200 rpm to obtain a mixed solution;

[0040] (2) taking 0.1 mL of the supernatant of the mixed solution obtained in step (1) for gradient dilution, and applying them respectively on a heterotrophic nitrification screening solid culture medium with a neutral pH, selecting single colonies with different morphologies and good growth for purification and culture, and finally screening out multiple strains of heterotrophic nitrifying bacteria after repeated screening and purification;

[0041] (3) selecting a single colony of heterotrophic nitrifying bacteria obtained in step (2) and inoculating it into a solid medium for screening aerobic denitrifying bacteria with a neutral pH, repeatedly screening and culturing for multiple times, selecting bacteria with good growth and storing them in 50% glycerol, precooling them in refrigerators at 4°C and -20°C for 30 minutes respectively, and finally storing them in a refrigerator at -80°C for long-term storage;

[0042] (4) The original strain stored in a -80°C refrigerator was inoculated into an 18×180 mm test tube containing 3 mL of aerobic denitrification medium at pH 5.5, and cultured at 30°C and 200 rpm for 24 h to confirm that the cell concentration was normal and the strain grew well;

[0043] (5) Take 200 uL of the bacterial solution obtained in step (4) and transfer it to an 18×180 mm test tube containing 3 mL of aerobic denitrification medium at pH 5.0, and culture it in a shaking incubator at 30° C. and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain grows well;

[0044] (6) Take 200 uL of the bacterial solution obtained in step (5) and transfer it to an 18×180 mm test tube containing 3 mL of aerobic denitrification medium at pH 4.5, and culture it in a shaking incubator at 30° C. and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain grows well;

[0045] (7) Take 80uL of the bacterial solution obtained in step (6), spread it on an aerobic denitrification solid medium, pick out single colonies with good growth, perform purification culture multiple times, obtain several strains with good growth, inoculate them into an aerobic denitrification medium with a pH of 4.5, and culture them in a shaking table at 30°C and 200rpm for 24h, then measure the nitrogen content in the fermentation liquid, and select the strain with the best denitrification effect for subsequent screening;

[0046] (8) The strain obtained in step (7) was gradually inoculated into an 18×180 mm test tube containing 3 mL of heterotrophic nitrification medium at pH 5.5, and cultured at 30° C. and 200 rpm for 24 h to confirm that the cell concentration was normal and the strain grew well;

[0047] (9) Take 200 uL of the bacterial solution obtained in step (8) and transfer it to an 18×180 mm test tube containing 3 mL of heterotrophic nitrification medium at pH 5.0. Incubate at 30°C and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain is growing well.

[0048] (10) Take 200 uL of the bacterial solution obtained in step (9) and transfer it to an 18×180 mm test tube containing 3 mL of heterotrophic nitrification medium at pH 4.5, and culture it in a shaking incubator at 30°C and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain is growing well;

[0049] (11) taking 80 uL of the bacterial solution obtained in step (10) in a heterotrophic nitrification medium at a pH of 4.5, spreading it on a heterotrophic nitrification solid medium, and picking out a single colony with good growth for purification and culture;

[0050] (12) The strain obtained in step (11) was inoculated into a heterotrophic nitrification medium with a pH of 4.5, and the nitrogen content in the fermentation broth was measured after culturing at 30° C. and 200 rpm on a shaker for 24 h to screen the strain with the best denitrification effect, that is, to screen out heterotrophic nitrification-aerobic denitrification bacteria with acid resistance;

[0051] The culture medium formula used is as follows (the pH value of the following culture medium is adjusted with 1 mol / L sterile hydrochloric acid):

[0052] Enrichment medium (g / L): C4H4Na2O4 4.7g, KNO3 1g, NH4Cl 1g, KH2PO4 0.007g, K2HPO4 0.027g, MgSO4 0.005g, trace element solution 2ml, pH 7.0-7.5;

[0053] Heterotrophic nitrification medium (g / L, nitrogen content 100 mg / L): C6H5Na3O7 5.375, NH4Cl0.382, KH2PO40.007, K2HPO4 0.35, MgSO4 0.005, trace element solution 2mL, pH 4.5.

[0054] Aerobic denitrification medium (g / L, nitrogen content 100 mg / L): KNO3 0.7214, C6H5Na3O75.375, KH2PO40.007, K2HPO4 0.35, MgSO4 0.005, trace element solution 2mL, pH 4.5.

[0055] Synchronous heterotrophic nitrification-aerobic denitrification medium (g / L, nitrogen content is 100 mg / L): KNO3 0.3607, NH4Cl0.191, C6H5Na3O7 5.375, KH2PO4 0.007, K2HPO4 0.35, MgSO4 0.005, trace element solution 2mL, pH 4.5.

[0056] Trace element solution (g / L): EDTA 0.1g, ZnSO4 . 7H2O 0.0078g, CaCl2 0.011g, MnCl ˙ 4H2O0.008g, FeSO 4˙ 7H2O 0.01g, (NH4)6Mo7O 24 0.0021 g, CuSO 4˙ 5H2O0.0032g, COCl 2˙ 6H2O0.0032g.

[0057] Preparation of seed solution: Take out the glycerol tube of HY24 strain stored in -80℃ refrigerator, and use a pipette to take 50-100μL into a newly sterilized 3mL liquid LB test tube in a clean bench. Place the test tube in a shaker at 28℃, 200rpm / min for 12-14h, inoculate it into 100mL sterile LB liquid culture medium for 12-14h, wash with sterile physiological saline, and add the same volume of sterile heterotrophic nitrification or aerobic denitrification culture medium to prepare the seed solution of the strain. The composition of LB culture medium (g / L): NaCl 10g, peptone 10g, yeast extract 5g, pH 7.0-7.5.

[0058] Denitrification performance test:

[0059] (1) Heterotrophic nitrification performance test

[0060] The above seed solution was inoculated into a heterotrophic medium with a pH of 4.5 at an inoculum of 2%, and cultured at 28°C and 200 rpm / min for 0 to 60 hours. The pH and OD600 values ​​of the fermentation liquid were measured every 12 hours from 0 hours, and the fermentation liquid was retained. Sodium citrate was used as the sole carbon source, ammonium chloride was used as the sole nitrogen source, the C / N ratio was 15, and the initial total nitrogen (TN) concentration was related to the ammonia nitrogen (NH4 + -N) concentration was 100 mg / L, and nitrate nitrogen concentration was 0; 8 mL of fermentation liquid was pipetted into a 10 mL centrifuge tube, and after balancing, centrifuged at 12000 rpm / min for 10 min using a high-speed centrifuge. 6 mL of supernatant was taken from the centrifuge tube and placed in a new 10 mL centrifuge tube to determine its nitrate nitrogen and ammonia nitrogen concentrations. The results are shown in Figure 1 shown.

[0061] Depend on Figure 1 It can be seen that during the heterotrophic nitrification process of strain HY24, the pH value in the fermentation broth rose slowly, reaching the highest value at 28h, and then stabilized at around 8.7; OD600 reached the maximum at 24h, and then the density of the bacteria began to decrease due to the lack of nutrients required for growth, and the OD600 value decreased slightly, and then stabilized; NH4 + -N concentration slowly decreases and can be completely removed in 48 hours, with a denitrification rate of 100%, but NO3 - -N began to appear after 48 hours, indicating that strain HY24 had a significant denitrification effect in acidic high-ammonia nitrogen wastewater; NO3 - -N increased slightly, indicating that NH4 + -N→NO3 - -N transformation pathway.

[0062] (2) Aerobic denitrification performance test

[0063] The above seed solution was inoculated in an aerobic medium with a pH of 4.5 at an inoculum of 2%, and cultured at 28°C and 200 rpm / min for 0 to 60 hours. The pH and OD600 values ​​of the fermentation liquid were measured every 12 hours from 0 hour, and the fermentation liquid was retained. Sodium citrate was used as the sole carbon source, potassium nitrate was used as the sole nitrogen source, the C / N ratio was 15, and the initial total nitrogen (TN) concentration was related to the nitrate nitrogen (NO3 - -N) concentration is 100mg / L and ammonia nitrogen concentration is 0; use a pipette to draw 8mL of fermentation liquid into a 10mL centrifuge tube, balance it and centrifuge it at 12000rpm / min for 10min in a high-speed centrifuge, take 6mL of supernatant from the centrifuge tube and put it into a new 10mL centrifuge tube to determine its nitrate nitrogen and ammonia nitrogen concentrations. The results are as follows Figure 2 shown.

[0064] Depend on Figure 2 It can be seen that the pH value of the fermentation liquid gradually increased from 4.5 to about 9.0 within 0 to 60 h, and the fermentation liquid gradually tended to be alkaline; OD 600 It reached its maximum value at 12h, and then the density of bacteria remained basically stable; NO3 - The -N content dropped significantly from 0 to 12 hours, and then slowly decreased to 37.8 mg / L at 60 hours, and the nitrate nitrogen removal rate was 62%. The denitrification effect was obvious; there was no NH4 + -N production, indicating that NO3 may not exist in strain HY24 - -N→NH4 + -N conversion pathway.

[0065] (3) Simultaneous nitrification and denitrification performance test

[0066] The seed liquid was inoculated with a 2% inoculum in a mixed nitrogen medium with a pH of 4.5, and cultured at 28°C and 200 rpm / min for 0 to 48 h. The pH and OD of the fermentation liquid were measured every 12 h starting from 0 h. 600 Sodium citrate was used as the sole carbon source, potassium nitrate and ammonium chloride were used as nitrogen sources, C / N was 15, the initial total nitrogen (TN) concentration was 100 mg / L, and the ammonia nitrogen and nitrate nitrogen concentrations were both 50 mg / L; 8 mL of fermentation liquid was taken with a pipette and placed in a 10 mL centrifuge tube, and after balancing, it was centrifuged in a high-speed centrifuge at 12000 rpm / min for 10 min, and 6 mL of supernatant was taken from the centrifuge tube and placed in a new 10 mL centrifuge tube to determine its ammonia nitrogen (NH4 + -N), nitrate nitrogen (NO3 - -N), total nitrogen (TN), COD, nitrite nitrogen (NO2 - -N) concentration. The results are as follows Figure 3 shown.

[0067] The results showed that the strain could simultaneously remove ammonium nitrogen and nitrate nitrogen from the fermentation broth under acidic mixed nitrogen (initial pH was 4.5, initial ammonium nitrogen and nitrate nitrogen contents were both 50 mg / L) Figure 3 A). The concentrations of ammonium nitrogen and nitrate nitrogen of strain HY24 decreased significantly within 12 hours. After 12 hours, the ammonium nitrogen remained almost unchanged, and the nitrate nitrogen gradually decreased. At 48 hours, the concentrations of ammonium nitrogen and nitrate nitrogen were 8.2 mg / L and 12.4 mg / L, respectively, and the removal rates were 84% and 75%, respectively. The above results show that when strain HY24 carries out simultaneous nitrification and denitrification in a mixed nitrogen source, the removal rate of ammonium nitrogen is lower than the removal rate of ammonia nitrogen when NH4Cl is the only nitrogen source, and the removal rate of nitrate nitrogen is higher than the removal rate of nitrate nitrogen when KNO3 is the only nitrogen source. The growth of the strain in a mixed nitrogen source reached its maximum at 24 hours and then tended to stabilize. The pH value in the fermentation broth gradually increased with the fermentation time, indicating that strain HY24 can still produce alkaline substances to neutralize the pH in the fermentation broth during simultaneous nitrification and denitrification. There was no accumulation of nitrite during the entire culture period. TN and COD in the fermentation broth gradually decreased, and at 48 hours, the removal rate of COD reached 94% ( Figure 3 B).

[0068] The above results show that strain HY24 can carry out simultaneous nitrification and denitrification in acidic nitrogen-containing wastewater. Its denitrification characteristics in mixed nitrogen sources are slightly different from those in single nitrogen sources, but the cell growth state and pH in the fermentation broth are similar to those in single nitrogen sources. Strain HY24 can adapt well to heterotrophic nitrification-aerobic denitrification process in acidic environment and does not accumulate nitrite, so it can be used for the treatment of acidic wastewater containing single or mixed nitrogen sources.

Claims

1. Acid-resistant heterotrophic nitrification-aerobic denitrification bacteria, characterized by: The heterotrophic nitrification-aerobic denitrification bacteria belongs to the genus Acinetobacter, is named Acinetobacter HY24, and is preserved in the China Center for Type Culture Collection with a preservation number of CCTCC NO: M20241231.

2. The use of the acid-resistant heterotrophic nitrification-aerobic denitrifying bacteria according to claim 1, characterized in that: Application in the treatment of acidic wastewater containing single or mixed nitrogen sources.

3. The method for screening acid-resistant heterotrophic nitrification-aerobic denitrifying bacteria according to claim 1, characterized in that: The following steps are involved: (1) 10 g of sludge from a municipal sewage treatment plant was added to 100 mL of enrichment liquid and incubated overnight at 30° C. and 200 rpm to obtain a mixed solution; (2) taking 0.1 mL of the supernatant of the mixed solution obtained in step (1) for gradient dilution, and applying them respectively on a heterotrophic nitrification screening solid culture medium with a neutral pH, selecting single colonies with different morphologies and good growth for purification and culture, and finally screening out multiple strains of heterotrophic nitrifying bacteria after repeated screening and purification; (3) selecting a single colony of heterotrophic nitrifying bacteria obtained in step (2) and inoculating it into a solid medium for screening aerobic denitrifying bacteria with a neutral pH, repeatedly screening and culturing for multiple times, selecting bacteria with good growth and storing them in 50% glycerol, precooling them in refrigerators at 4°C and -20°C for 30 minutes respectively, and finally storing them in a refrigerator at -80°C for long-term storage; (4) The original strain stored in a -80°C refrigerator was inoculated into an 18×180 mm test tube containing 3 mL of aerobic denitrification medium at pH 5.5, and cultured at 30°C and 200 rpm for 24 h to confirm that the cell concentration was normal and the strain grew well; (5) Take 200 uL of the bacterial solution obtained in step (4) and transfer it to an 18×180 mm test tube containing 3 mL of aerobic denitrification medium at pH 5.0, and culture it in a shaking incubator at 30° C. and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain grows well; (6) Take 200 uL of the bacterial solution obtained in step (5) and transfer it to an 18×180 mm test tube containing 3 mL of aerobic denitrification medium at pH 4.5, and culture it in a shaking incubator at 30° C. and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain grows well; (7) Take 80uL of the bacterial solution obtained in step (6), apply it on an aerobic denitrification solid medium, pick out single colonies with good growth and perform purification culture multiple times to obtain several strains with good growth, and separate them into Inoculate into aerobic denitrification medium with a pH of 4.5, culture at 30°C and 200 rpm in a shaker for 24 h, measure the nitrogen content in the fermentation broth, and select the strain with the best denitrification effect for subsequent screening; (8) The strain obtained in step (7) was gradually inoculated into an 18×180 mm test tube containing 3 mL of heterotrophic nitrification medium at pH 5.5, and cultured at 30° C. and 200 rpm for 24 h to confirm that the cell concentration was normal and the strain grew well; (9) Take 200 uL of the bacterial solution obtained in step (8) and transfer it to an 18×180 mm test tube containing 3 mL of heterotrophic nitrification medium at pH 5.

0. Incubate at 30°C and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain is growing well. (10) Take 200 uL of the bacterial solution obtained in step (9) and transfer it to an 18×180 mm test tube containing 3 mL of heterotrophic nitrification medium at pH 4.5, and culture it in a shaking incubator at 30°C and 200 rpm for 24 h to confirm that the cell concentration is normal and the strain is growing well; (11) taking 80 uL of the bacterial solution obtained in step (10) in a heterotrophic nitrification medium at a pH of 4.5, spreading it on a heterotrophic nitrification solid medium, and picking out a single colony with good growth for purification and culture; (12) The strain obtained in step (11) was inoculated into a heterotrophic nitrification medium with a pH of 4.5, and the nitrogen content in the fermentation broth was measured after culturing at 30° C. and 200 rpm on a shaker for 24 h to screen the strain with the best denitrification effect, that is, to screen out heterotrophic nitrification-aerobic denitrification bacteria with acid resistance; The pH values ​​of the above culture media were adjusted with 1 mol / L sterile hydrochloric acid.

4. The method for screening acid-resistant heterotrophic nitrification-aerobic denitrifying bacteria according to claim 3, characterized in that: The effective component content per liter of the enrichment medium is: C4H4Na2O4 4.7g, KNO3 1g, NH4Cl 1g, KH2PO40.007g, K2HPO4 0.027g, MgSO4 0.005g, trace element solution 2ml, pH 7.0-7.5; The effective component contents per liter of the heterotrophic nitrification culture medium are: C6H5Na3O7 5.375 g, NH4Cl 0.382 g, KH2PO4 0.007 g, K2HPO4 0.35 g, MgSO4 0.005 g, and trace element solution 2 mL; The effective component contents per liter of the aerobic denitrification culture medium are: KNO3 0.7214g, C6H5Na3O7 5.375g, KH2PO4 0.007g, K2HPO4 0.35g, MgSO4 0.005g, and trace element solution 2mL; The effective component content of the trace element solution per liter is: EDTA 0.1g, ZnSO4 . 7H2O0.0078g, CaCl20.011g, MnCl ˙ 4H2O 0.008g, FeSO 4˙ 7H2O 0.01g, (NH4)6Mo7O 24 0.0021 g, CuSO 4˙ 5H2O 0.0032g, COCl 2˙ 6H2O 0.0032g.

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