Heterotrophic nitrification-aerobic denitrification pseudomonas with low temperature resistance and application thereof

Abstract

The present application relates to the technical field of microorganism, and provide a kind of heterotrophic nitrification-aerobic denitrification pseudomonas sp. With application of low temperature resistance, the strain is pseudomonas sp. SW1, preservation number is CCTCC NO: M 20221797.The heterotrophic nitrification-aerobic denitrification bacteria pseudomonas sp. SW1 of low temperature resistance of the present application has the characteristics of low temperature resistance, grows well at 4-10 ℃, simultaneously has strong heterotrophic nitrification-aerobic denitrification denitrification capacity, and the enrichment culture of strain is carried out in relatively low nitrogen source, and this condition is extremely consistent with the application scene of strain in domestic sewage.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, and in particular to a low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas aeruginosa and its applications. Background Technology

[0002] With the rapid development of my country's economy and the acceleration of urbanization, the issue of domestic sewage discharge has received increasing attention. The volume of domestic sewage discharged in my country continues to grow, and the sewage composition is complex and diverse, making treatment increasingly difficult. Currently, my country's urban sewage treatment plant pollutant discharge standards are divided into Class A, Class B, Class II, and Class III standards, mainly controlling 12 pollutant indicators, including Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD5), Suspended Solids (SS), Animal and Vegetable Oils, Total Nitrogen (as N), Ammonia Nitrogen (as N), and Total Phosphorus (as P). In low-temperature environments, the physical, chemical, and biological properties of sewage change. Low temperatures increase sewage viscosity and reduce sedimentation performance, affecting the operating efficiency of sewage treatment equipment. Simultaneously, low temperatures inhibit microbial activity, reducing the rate of organic matter degradation during biological treatment and resulting in poor nitrogen and phosphorus removal, posing numerous challenges to sewage treatment. my country's sewage discharge standards even include separate winter ammonia nitrogen discharge concentration standards for this reason. Furthermore, low temperatures can also cause sludge bulking during sewage treatment, further increasing treatment difficulty and costs.

[0003] CN115725477A discloses a wide-temperature-range heterotrophic nitrifying-aerobic denitrifying pale yellow Pseudomonas aeruginosa. After being cultured at 5℃ for 5 days, the denitrification efficiency of this strain for ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen was 45.8%, 52.9%, and 49.8%, respectively. Its low-temperature denitrification efficiency is relatively slow. Therefore, cultivating a strain with faster denitrification efficiency under low-temperature conditions is of great significance for wastewater treatment facilities operating in cold regions or during winter. Summary of the Invention

[0004] In view of this, the present invention proposes a low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas aeruginosa with high denitrification efficiency under low-temperature conditions and its application.

[0005] The technical solution of the present invention is implemented as follows: In the first aspect, the present invention provides a low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas strain, wherein the strain is Pseudomonas sp. SW1, with accession number CCTCCNO: M 20221797.

[0006] Secondly, this invention provides an application of low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas aeruginosa in removing inorganic nitrogen pollutants from wastewater under low-temperature conditions.

[0007] Based on the above technical solutions, preferably, the temperature of the wastewater is not lower than 4°C.

[0008] Based on the above technical solutions, preferably, the pH value of the wastewater is 5-11.

[0009] Based on the above technical solutions, preferably, the dissolved oxygen content in the wastewater is 2-8 mg / L.

[0010] Based on the above technical solutions, preferably, the inorganic nitrogen is one or more of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen.

[0011] Based on the above technical solutions, preferably, Pseudomonas SW1 is added to the wastewater to be treated to remove inorganic nitrogen pollutants from the water, and the OD600 value of the bacterial agent is 0.01±0.001.

[0012] Thirdly, the present invention provides a bacterial agent for low-temperature denitrification, comprising the aforementioned Pseudomonas sp. SW1.

[0013] The low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas sp. SW1 of the present invention and its application have the following beneficial effects compared with the prior art: The low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas sp. SW1 of the present invention has the characteristic of low temperature resistance. It still has a certain nitrogen metabolism capacity in an environment of 4℃, and has a wide temperature tolerance range, from 4℃ to 40℃, and can metabolize ammonia nitrogen. In addition, it can metabolize 99% of ammonia nitrogen at 10-30℃, and the total nitrogen removal rate is about 70%. It has a strong heterotrophic nitrification-aerobic denitrification nitrogen removal capacity. Moreover, the enrichment culture of the strain is carried out in a relatively low nitrogen source. This condition is extremely consistent with the application scenario of the strain in domestic sewage. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This shows the colony morphology of the bacterial strain of this invention on agar medium;

[0016] Figure 2 The denitrification efficiency of the strain of this invention when ammonia nitrogen is the only nitrogen source;

[0017] Figure 3 The denitrification efficiency of the strain of this invention when nitrate nitrogen is the only nitrogen source;

[0018] Figure 4 The denitrification efficiency of the strain of this invention when nitrite is the only nitrogen source;

[0019] Figure 5 The denitrification efficiency of the strain of the present invention at different pH values;

[0020] Figure 6 The denitrification efficiency of the strain of the present invention at different temperatures;

[0021] Figure 7 The denitrification efficiency of the strain of this invention under different carbon sources

[0022] Figure 8 The denitrification efficiency of the strain of this invention under different C / N ratios;

[0023] Figure 9 The figures show the contour plots and response surface plots of the effect of temperature and pH on total nitrogen removal rate in the Box-Behnken Design experiment. Figure (a) is the response surface plot and Figure (b) is the contour plot.

[0024] Figure 10 The figures show contour plots and response surface plots of the total nitrogen removal rate based on the test temperature and C / N ratio in the Box-Behnken Design experiment. Figure (a) is the response surface plot, and Figure (b) is the contour plot.

[0025] Figure 11 The figures show contour plots and response surface plots of pH and C / N ratio for total nitrogen removal in the Box-Behnken Design experiment. Figure (a) is the response surface plot and Figure (b) is the contour plot.

[0026] Figure 12 The denitrification effect of the strain of this invention in domestic wastewater was tested.

[0027] Figure 13 This is a test of the denitrification effect of the strain of the present invention in dyeing and printing wastewater. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] This invention provides a low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas strain and its application. The strain is Pseudomonas sp. SW1, deposited at the China Center for Type Culture Collection (CCTCC), Wuhan University, Wuhan, China, on November 14, 2022, with accession number CCTCC NO: M 20221797. The strain was identified as active on November 21, 2022.

[0030] This invention also provides an application of low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas bacteria in removing ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen from wastewater under low-temperature conditions: Pseudomonas SW1 is added to the wastewater to be treated to remove inorganic nitrogen pollutants. The OD600 value of the bacterial agent is 0.01±0.001, the wastewater temperature is not lower than 4℃, the pH value is 5-11, the C / N ratio is 9-15, and the dissolved oxygen content is 2-8 mg / L. The inorganic nitrogen is one or more of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen.

[0031] The following examples further illustrate the present invention, but do not constitute a limitation thereof. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0032] I. Isolation and Identification of Strains

[0033] The strain was isolated by the inventor from a sample of domestic sewage in 2022. The culture method is as follows: (1) Isolation method

[0034] Take 100 mL of rural domestic sewage sample into a 250 mL Erlenmeyer flask, add NH4Cl to the sample to achieve a concentration of nitrate nitrogen of 30 mg / L, and perform screening and acclimatization. Seal the flask with sealing film to ensure aerobic conditions during metabolism, and place the Erlenmeyer flask in a constant temperature shaking incubator at 10℃ and 150 rpm for incubation, monitoring the ammonia nitrogen concentration. When the ammonia nitrogen concentration is undetectable, inoculate 10 mL of the enrichment solution into a 250 mL Erlenmeyer flask containing 100 mL of enrichment medium and continue the above incubation method.

[0035] After five consecutive transfers, the enriched culture was diluted and spread on a solid medium. After incubation at 10°C until visible colonies were formed, single colonies were picked and streaked onto plates for isolation. After five rounds of streaking, pure strains were obtained.

[0036] Liquid culture medium formula: Magnesium sulfate (MgSO4) 0.18-0.22 g / L, Sodium chloride (NaCl) 2 g / L, Dipotassium hydrogen phosphate (K2HPO4) 0.08-0.12 g / L, Sodium bicarbonate (NaHCO3) 0.8-1.2 g / L, Ammonium chloride (NH4Cl) 0.112-0.116 g / L, Sodium acetate (CH3COONa) 1.010-1.036 g / L, Trace elements 1 mL, Ferrous sulfate heptahydrate (FeSO4·7H2O) 0.050 g / 10 mL.

[0037] The formula for the trace element stock solution is as follows: copper sulfate pentahydrate (CuSO4·5H2O) 0.1 g / L, zinc sulfate heptahydrate (ZnSO4·7H2O) 0.5 g / L, cobalt chloride hexahydrate (CoCl2·6H2O) 0.5 g / L, manganese sulfate tetrahydrate (MnSO4·4H2O) 0.2 g / L, sodium molybdate dihydrate (Na2MoO4·2H2O) 0.1 g / L, and boric acid (H3BO3) 0.1 g / L.

[0038] Solid culture medium is made by adding 1-2% by weight of agar powder to liquid culture medium.

[0039] (2) Strain identification

[0040] 1. Observation of bacterial morphology

[0041] The bacterial strain was cultured at 10℃ and 150r / min to the logarithmic phase. The bacterial solution was diluted and evenly spread on a solid plate, and then cultured at 10℃ in a biochemical incubator. After a single colony was formed on the plate, it was observed and examined under a Gram stain.

[0042] 2. Colony morphology characteristics

[0043] The colonies are pale yellow, round, with a raised center, smooth surface, slightly moist, and tend to stick together when picked up. They are Gram-negative, with short rod-shaped cells, each 2.5-3.5 μm long and 0.8-1.2 μm wide (see...). Figure 1 ).

[0044] 3. Molecular identification of strains

[0045] Using bacterial genome as DNA template, 16S rRNA was amplified using 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'-GGTTACCTTGTTACGACTT-3') as upstream and downstream primers.

[0046] The PCR reaction conditions were as follows: 94℃ pre-denaturation for 4 min; 94℃ denaturation for 25 s, 58℃ annealing for 30 s, 72℃ extension for 30 s, for a total of 25 cycles; final extension at 72℃ for 5 min. After amplification, the PCR products were subjected to 1% agarose gel electrophoresis to check the integrity of the PCR products. Finally, the PCR products were sent to the sequencing department of Sangon Biotech (Shanghai) Co., Ltd. for sequencing.

[0047] The amplified strain's 16S rDNA gene contained an effective nucleotide sequence of approximately 1443 bp, as shown in SEQ ID NO:1. This sequence was input into GenBank and compared with database sequences using Blast software. The results showed a high similarity (100%) to the 16S rDNA sequence of *Pseudomonas sp.*. Based on the phylogenetic analysis of the 16S rDNA gene and its physiological and biochemical characteristics, a new strain of *Pseudomonas sp.* was identified and named SW1 (hereinafter referred to as "strain SW1"). This strain has been deposited at the China Center for Type Culture Collection (CCTCC), accession number: CCTCC M 20221797.

[0048] II. Nitrogen metabolism characteristics of strain SW1

[0049] (1) Heterotrophic nitrification-aerobic denitrification performance test of strain SW1

[0050] Preparation of bacterial suspension of strain SW1: (1) Pseudomonas SW1 strain was inoculated into liquid culture medium and cultured to the logarithmic growth phase. The resulting bacterial suspension was centrifuged to remove the supernatant and washed with sterile physiological saline to obtain Pseudomonas SW1 mother liquor; (2) Liquid culture medium was prepared and sterilized in an autoclave at 103.4 kPa and 121°C for 20 min and cooled to room temperature; (3) Pseudomonas SW1 mother liquor was added to the cooled culture medium and fermented to obtain Pseudomonas SW1 liquid bacterial suspension (OD600≈0.01).

[0051] Using ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen as the sole nitrogen sources, with a C / N ratio of 10, strain SW1 was inoculated at a 1% (v / v) inoculation ratio into 250 ml Erlenmeyer flasks containing 100 mL of the above-mentioned liquid culture medium. The bacterial suspension of strain SW1 (OD600≈0.01) was then incubated at 10°C with a shaker speed of 150 rpm. Samples were taken every 6 hours during the incubation period to measure the ammonia nitrogen and total nitrogen concentrations of the culture medium. The results are shown below. Figures 2-4 As shown.

[0052] Depend on Figures 2-4It can be seen that when ammonia nitrogen is used as the sole nitrogen source, strain SW1 can achieve a removal rate of 99.98% for ammonia nitrogen and a removal rate of 59.46% for total nitrogen (see...). Figure 2 When nitrate nitrogen is used as the sole nitrogen source, strain SW1 can achieve a nitrate nitrogen removal rate of 97.65% and a total nitrogen removal rate of 59.16% (see...). Figure 3 When nitrite was used as the sole nitrogen source, strain SW1 achieved a nitrite removal rate of 78.10% and a total nitrogen removal rate of 47.74% (see [link to relevant documentation]). Figure 4 This demonstrates that the strain SW1 of the present invention can remove ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen, and has a wide range of applications.

[0053] III. Optimization of culture conditions for strain SW1

[0054] (1) The effect of strain SW1 on heterotrophic nitrification-aerobic denitrification nitrogen removal at different pH values

[0055] A bacterial suspension of strain SW1 (OD600≈0.01) was inoculated at a 1% (v / v) ratio into 100 mL of the above-mentioned culture medium in a 250 mL Erlenmeyer flask. The flask was incubated at different pH values ​​(5, 7, 9, 10, 11) with a shaking speed of 150 rpm. The initial ammonia nitrogen concentration was set at 30 mg / L, and the culture was incubated for 30 h. During this period, samples were taken to measure the ammonia nitrogen concentration and total nitrogen concentration of the culture medium after 30 h. The results are shown below. Figure 5 .

[0056] like Figure 5 As shown, at pH 5, 41.95% of the ammonia nitrogen in the culture medium was still removed. At pH 7 and 9, strain SW1 could remove more than 99.48% of the ammonia nitrogen, and the removal rate of total nitrogen could also reach about 70%. At pH 10, strain SW1 removed 83.06% of the ammonia nitrogen and 52.31% of the total nitrogen. At pH 11, 73.54% of the ammonia nitrogen in the culture medium was still removed. This indicates that strain SW1 can tolerate strong alkalinity at pH 10-11 and has certain application prospects in the treatment of strongly alkaline wastewater (such as dyeing and printing wastewater).

[0057] (2) The effect of heterogeneous nitrification-aerobic denitrification nitrogen removal by strain SW1 at different temperatures

[0058] A bacterial suspension of strain SW1 (OD600≈0.01) was inoculated at a 1% (v / v) ratio into 100 mL of the above-mentioned culture medium in a 250 mL Erlenmeyer flask. The flasks were then incubated at different temperatures (4℃, 10℃, 20℃, 30℃, and 40℃). The rotation speed was set to 150 r / min, and the initial ammonia nitrogen concentration was 30 mg / L. The culture was incubated for 30 h. During this period, samples were taken to measure the ammonia nitrogen and total nitrogen concentrations of the culture medium after 30 h. The results are shown below. Figure 6 .

[0059] like Figure 6 As shown, strain SW1 can metabolize 44.75% of ammonia nitrogen at 4℃. When the temperature is raised to 10℃ and cultured for 30 hours, strain SW1 can achieve ammonia nitrogen removal rate of 99.71% and total nitrogen removal rate of 72.13%. Further increasing the temperature to 40℃, although the ammonia nitrogen removal rate of strain SW1 decreases slightly, it still reaches 97.38%.

[0060] This indicates that strain SW1 can adapt to aquatic environments ranging from 4 to 40°C, with a stronger nitrogen removal capacity at temperatures between 10 and 40°C.

[0061] (3) Heterogeneous nitrification-aerobic denitrification effect of strain SW1 under different carbon sources

[0062] Carbon sources, acting as electron donors, provide energy for bacterial growth and metabolism. They are also an indispensable part of wastewater treatment processes and a key environmental factor in aerobic denitrification. This study selected sucrose, glucose, citrate, acetate, and succinate as carbon sources to investigate the nitrogen metabolism efficiency of strain SW1. A bacterial suspension of strain SW1 (OD600≈0.01) was inoculated at a 1% inoculation ratio into 100 mL of the aforementioned culture medium in a 250 mL Erlenmeyer flask. The culture temperature was 10℃, the rotation speed was 150 r / min, and the initial ammonia nitrogen concentration was 30 mg / L. The culture was maintained for 30 h. During this period, samples were taken to measure the ammonia nitrogen and total nitrogen concentrations of the culture medium after 30 h. The results are shown below. Figure 7 .

[0063] like Figure 7 As shown, when sucrose is the sole carbon source, strain SW1 achieves a 42.29% removal rate of ammonia nitrogen. When acetate, citrate, and succinate are used as carbon sources, strain SW1 maintains a removal rate of over 99.45% for ammonia nitrogen and 66.34%, 74.41%, and 58.56% for total nitrogen, respectively. However, when glucose is the sole carbon source, strain SW1 only achieves a 20.36% removal rate of ammonia nitrogen. This indicates that using acetate, citrate, and succinate as carbon sources can enhance the nitrogen removal capacity of strain SW1.

[0064] (4) The nitrogen removal effect of strain SW1 under different C / N ratios: heterogeneous nitrification-aerobic denitrification

[0065] A bacterial suspension of strain SW1 (OD600≈0.01) was inoculated at a 1% inoculation ratio into 100 mL Erlenmeyer flasks containing the above-mentioned culture medium. The flasks were then cultured at different C / N ratios (3, 6, 9, 12, 15). The culture temperature was set at 10℃, and the initial ammonia nitrogen concentration was 30 mg / L. The culture was carried out for 30 h. During this period, samples were taken to measure the ammonia nitrogen and total nitrogen concentrations of the culture medium after 30 h. The results are shown below. Figure 8 .

[0066] like Figure 8 As shown, with the increase of C / N ratio, the efficiency of heterotrophic nitrification-aerobic denitrification of strain SW1 becomes higher and higher. When the C / N ratio is 3 and 6, the removal rate of ammonia nitrogen by strain SW1 is 38.79% and 76.36%, respectively; when the C / N ratio is 9, the removal rate of ammonia nitrogen by strain SW1 can reach 94.38%; when the C / N ratio is 12 and 15, the removal rate of ammonia nitrogen by strain SW1 is above 99.65%, and the removal rate of total nitrogen also increases to 78.31%.

[0067] This indicates that strain SW1 can adapt to aquatic environments with a C / N ratio of 3-15, with a stronger nitrogen removal capacity at a C / N ratio of 9-15.

[0068] (5) Optimization of culture conditions for strain SW1

[0069] Using Design-expert software, with total nitrogen removal rate as the response value, pH value 7-11, temperature 10-40℃ and C / N ratio 3-15 were selected as factors and value ranges. Each factor was assigned three levels: low, medium and high. The specific design is shown in Table 5.

[0070] Table 1 Independent variables and level codes

[0071]

[0072] The experimental design and results are shown in Table 2 (Note: the initial ammonia nitrogen content was 30 mg / L, and the total nitrogen removal rate was 30 h).

[0073] Table 2 Experimental Design and Results

[0074] Serial Number C / N Temperature (°C) Total nitrogen removal rate (%) 1 10.5 10 71.89 2 15 25 77.19 3 10.5 25 78.28 4 15 40 58.35 5 6 40 32.22 6 10.5 25 76.12 7 15 25 43.18 8 10.5 25 73.78 9 10.5 10 42.40 10 10.5 40 62.38 11 6 25 31.26 12 10.5 40 33.85 13 6 10 44.16 14 6 25 40.26 15 10.5 25 75.32 16 15 10 64.26 17 10.5 25 75.25

[0075] As shown in Table 2, strain SW1 can effectively remove total nitrogen under conditions of C / N ratio of 6-15, temperature of 10-40℃, and pH of 7-11. It can also tolerate strong alkalinity at pH of 10-11 in an environment of 10℃, and can be applied to the treatment of strongly alkaline wastewater under low temperature conditions in northern winters.

[0076] Construction and feasibility analysis of the heterotrophic nitrification model: Experimental results were analyzed using Design-Expert software. The relationship between factors (C / N, temperature, pH) and response values ​​(total nitrogen removal rate) was fitted using a quadratic polynomial, and the equation was derived:

[0077]

[0078] In the above formula, Y represents the total nitrogen removal rate, and X1, X2, and X3 represent the coded values ​​of C / N, temperature, and pH, respectively. The homogeneity of variance test using ANOVA was used to study the effects of each factor and its interaction on the response value (total nitrogen removal rate), verifying the goodness of fit of the coded value equation. The results are shown in Table 3.

[0079] Table 3. Response surface methodology analysis of strain SW1

[0080] factor sum of squares Degrees of freedom Mean Square F value p-value Significance Model 5097.14 9 566.35 99.31 ＜0.0001 significant AC / N 1130.25 1 1130.25 198.19 ＜0.0001 BT 161.28 1 161.28 28.28 0.0011 C-pH 1275.91 1 1275.91 223.73 ＜0.0001 AB 9.09 1 9.09 1.59 0.2472 AC 156.45 1 156.45 27.43 0.0012 BC 0.2325 1 0.2325 0.0408 0.8457 <![CDATA[A 2 ]]> 989.63 1 989.63 173.53 ＜0.0001 <![CDATA[B 2 ]]> 480.03 1 480.03 84.17 ＜0.0001 <![CDATA[C 2 ]]> 652.41 1 652.41 114.4 ＜0.0001 Residual 39.92 7 5.7 Lack of Fit 29.08 3 9.69 3.57 0.1251 not significant Pure Error 10.85 4 2.71 Cor Total 5137.06 16

[0081] The F-value and P-value determine the significance of the heterotrophic nitrification model. A larger F-value and a smaller P-value indicate a stronger model significance. Table 3 shows that the P-value of this experimental model is <0.001, indicating that the model equation is significant. The lack-fit term is an important data point for evaluating the reliability of the equation; if significant, it indicates poor simulation and requires adjustment; if insignificant, it indicates good simulation. The lack-fit term of this fitted model is 0.1251 > 0.01, indicating that the model is not significant at the 0.01 level. The lack-fit term and pure error are not significant, indicating a good model fit and good stability of the experiment.

[0082] The effects of C / N ratio, temperature, and pH on the nitrification and denitrification capacity of strain SW1 and the interactions among the three factors were studied using response surface methodology. The results are shown in [Figure number missing]. Figure 9-11 .

[0083] Figure 9-11 The influence of the three factors on the total nitrogen removal rate of strain SW1, from largest to smallest, is as follows: initial pH value > temperature > carbon-to-nitrogen ratio. The optimal conditions for heterotrophic nitrification nitrogen removal by strain SW1 are: carbon-to-nitrogen ratio of 8.924, pH value of 7.909, and temperature of 22.766℃, with a maximum total nitrogen removal rate of 72.232%. Through F-test, p-value, lack-of-fit analysis, and validation experiments under optimal conditions, the model is proven to be effective and reliable in predicting the influence of each factor on the heterotrophic nitrification TN removal rate of strain SW1.

[0084] IV. Application Test of Strain 1 in Domestic Sewage

[0085] 50L of domestic wastewater was collected from the inlet of a domestic wastewater treatment system in Wuhan, Hubei Province. The initial water quality parameters were: ammonia nitrogen 38mg / L, total nitrogen 44mg / L, COD 454mg / L, pH = 7.6, and salinity 0.1%. The wastewater was divided into six 8L plastic cups. Three of these cups were treated with a 1% (v / v) bacterial suspension of strain SW1 (OD600 ≈ 0.01), while the other three served as a control group. All cups were incubated at 10℃ with air introduced through an aerator, maintaining a dissolved oxygen level of 5mg / L. During the test, the changes in ammonia nitrogen, total nitrogen, and COD levels were monitored periodically. The aerobic nitrification and denitrification denitrification capacity of the strain was analyzed. The results are shown below. Figure 12 .

[0086] Depend on Figure 12 It can be seen that the ammonia nitrogen removal rate in the bacterial-added group can reach 99.06%, and the total nitrogen removal rate can reach 56.57%, while the ammonia nitrogen removal rate in the control group is 49.61%, and the total nitrogen removal rate is 24.43%. The denitrification efficiency of strain SW1 in domestic wastewater is very significant. This shows that strain SW1 of the present invention exhibits good aerobic nitrification and denitrification capabilities.

[0087] Example 2: Application Test of Strains in Dyeing and Printing Wastewater

[0088] 25L of dyeing and printing wastewater was collected from the inlet of the wastewater treatment system of a dyeing and printing factory in Jiaxing. The effluent quality of the wastewater was as follows: ammonia nitrogen: 67mg / L, total nitrogen: 93mg / L, COD: 2100mg / L, pH: 10.3, and salinity: 1.4%. The wastewater was divided into six 5L plastic cups. Three of these cups were treated with a 5% suspension of strain SW1 (OD600≈0.01), while the other three served as a control group. All cups were placed in a 10℃ incubator with air introduced through an aerator, maintaining a dissolved oxygen level of 5mg / L. During the test, the changes in ammonia nitrogen, total nitrogen, and COD levels in the system were monitored periodically. The aerobic nitrification and denitrification denitrification capacity of the strain was analyzed. The results are shown in […]. Figure 13 .

[0089] Figure 13 As shown, the ammonia nitrogen removal rate in the bacterial-added group reached 86.27%, and the total nitrogen removal rate reached 50.93%, while the ammonia nitrogen and total nitrogen in the control group remained almost unchanged. The denitrification efficiency of strain SW1 in dyeing and printing wastewater is very significant. This demonstrates that strain SW1 of this invention exhibits excellent aerobic nitrification and denitrification capabilities.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas, characterized in that: The pseudomonads ( Pseudomonas sp. The accession number of SW1 is CCTCC NO: M 20221797.

2. The application of the low-temperature resistant heterotrophic nitrifying-aerobic denitrifying Pseudomonas bacillus described in claim 1 in removing inorganic nitrogen pollutants from wastewater under low-temperature conditions.

3. The application as described in claim 2, characterized in that: The temperature of the wastewater is not lower than 4℃.

4. The application as described in claim 2, characterized in that: The pH value of the wastewater is 5-11.

5. The application as described in claim 2, characterized in that: The dissolved oxygen content in the wastewater is 2-8 mg / L.

6. The application as described in claim 2, characterized in that: The inorganic nitrogen is one or more of ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen.

7. The application as described in claim 2, characterized in that: Pseudomonas SW1 was added to the wastewater to be treated to remove inorganic nitrogen pollutants from the water. The OD600 value of the bacterial agent was 0.01±0.

001.

8. A bacterial agent for low-temperature denitrification, characterized in that: Including the Pseudomonas as described in claim 1 ( Pseudomonas sp. SW1.

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