Low-temperature-resistant heterotrophic nitrification-aerobic denitrification pseudomonas and application thereof

Abstract

The invention relates to the technical field of microorganisms, and provides a low-temperature-resistant heterotrophic nitrification-aerobic denitrification pseudomonas and application thereof, the strain is pseudomonas (Pseudomonas sp.) SW1, and the preservation number is CCTCC (China Center for Type Culture Collection) NO: M 20221797. The low-temperature-resistant heterotrophic nitrification-aerobic denitrification bacterium Pseudomonas sp. SW1 has the characteristic of low temperature resistance, can well grow at 4-10 DEG C, and has relatively strong heterotrophic nitrification-aerobic denitrification nitrogen removal capability, and the enrichment culture of the strain is carried out in a relatively low nitrogen source, and the condition is extremely consistent with the application scene of the strain in domestic sewage.

Description

Technical Field

[0001] The invention relates to the technical field of microorganisms, and in particular to low-temperature-resistant heterotrophic nitrification-aerobic denitrification Pseudomonas and applications thereof. Background Art

[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 amount of domestic sewage discharged in my country continues to grow, and the composition of sewage is complex and diverse, making it increasingly difficult to treat. At present, the pollutant discharge standards for urban sewage treatment plants in my country are divided into Class A standards, Class B standards, Class II standards, and Class III standards. The main controlled pollutant indicators involve 12 items, including chemical oxygen demand (COD), biochemical oxygen demand (BOD5), suspended solids (SS), animal and vegetable oils, total nitrogen (in terms of N), ammonia nitrogen (in terms of N), and total phosphorus (in terms of P). In a low temperature environment, the physical, chemical, and biological properties of sewage change. Among them, low temperature will increase the viscosity of sewage and deteriorate the sedimentation performance, affecting the operating efficiency of sewage treatment equipment. At the same time, low temperature inhibits the activity of microorganisms, reduces the degradation rate of organic matter in the biological treatment process, and the poor nitrogen and phosphorus removal effects bring many challenges to sewage treatment. my country's sewage discharge standards even set a separate winter ammonia nitrogen discharge concentration standard. In addition, low temperatures may also cause problems such as sludge bulking during sewage treatment, further increasing the difficulty and cost of treatment.

[0003] CN115725477A discloses a wide temperature range heterotrophic nitrification-aerobic denitrification Pseudomonas flavus. After being cultured at 5°C for 5 days, the denitrification effects of the strain on ammonia nitrogen, nitrate nitrogen and nitrite nitrogen are 45.8%, 52.9% and 49.8% respectively. Its low-temperature denitrification efficiency is relatively slow. Therefore, cultivating a strain with a faster denitrification efficiency under low temperature conditions is of great significance for sewage treatment facilities operating in cold areas or in winter, which have high denitrification performance. Summary of the invention

[0004] In view of this, the present invention proposes a low-temperature resistant heterotrophic nitrification-aerobic denitrification Pseudomonas with faster denitrification efficiency under low temperature conditions and application thereof.

[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 nitrification-aerobic denitrification Pseudomonas, wherein the strain is Pseudomonas sp. SW1, and the preservation number is CCTCCNO: M 20221797.

[0006] In a second aspect, the present invention provides an application of low-temperature-resistant heterotrophic nitrification-aerobic denitrification Pseudomonas to remove inorganic nitrogen pollutants in sewage under a low-temperature environment.

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

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

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

[0010] On the basis of the above technical solution, preferably, the inorganic nitrogen is one or more of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen.

[0011] On the basis of the above technical solution, preferably, Pseudomonas SW1 is added to the sewage to be treated to remove inorganic nitrogen pollutants in the water, and the OD600 value of the bacterial agent is 0.01±0.001.

[0012] In a third aspect, the present invention provides a bacterial agent for low-temperature denitrification, comprising the above-mentioned Pseudomonas sp. SW1.

[0013] The low-temperature-resistant heterotrophic nitrification-aerobic denitrifying Pseudomonas sp. and its application in the present invention have the following beneficial effects compared with the prior art: the low-temperature-resistant heterotrophic nitrification-aerobic denitrifying bacteria Pseudomonas sp. SW1 of the present invention has the characteristic of being resistant to low temperatures, still has a certain nitrogen metabolism ability in an environment of 4°C, and has a wide temperature tolerance range, can metabolize ammonia nitrogen from 4°C to 40°C, and can metabolize 99% of ammonia nitrogen at 10-30°C, and the total nitrogen removal rate is also about 70%, has strong heterotrophic nitrification-aerobic denitrification denitrification ability, and the enrichment culture of the strain is carried out in a relatively low nitrogen source, and this condition is extremely consistent with the application scenario of the strain in domestic sewage. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 The colony morphology of the strain of the present invention on agar medium;

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

[0017] Figure 3 is the denitrification efficiency of the strain of the present invention when nitric nitrogen is the only nitrogen source;

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

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

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

[0021] Figure 7 is the denitrification efficiency of the strain of the present invention under different carbon sources

[0022] Figure 8 is the denitrification efficiency of the strain of the present invention at different C / N ratios;

[0023] Fig. 9 The contour map and response surface map of the Box-BehnkenDesign test temperature and pH on total nitrogen removal rate. Figure (a) is the response surface map, and Figure (b) is the contour map;

[0024] Fig.10 The contour map and response surface map of Box-BehnkenDesign test temperature and C / N on total nitrogen removal rate. Figure (a) is the response surface map, and Figure (b) is the contour map.

[0025] Fig.11 The contour map and response surface map of the Box-BehnkenDesign test on the effects of pH and C / N on total nitrogen removal efficiency. Figure (a) is the response surface map, and Figure (b) is the contour map.

[0026] Fig.12 The denitrification test effect of the strain of the present invention in domestic wastewater;

[0027] Fig.13 The denitrification test effect of the strain of the present invention in printing and dyeing wastewater. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The present invention provides a low-temperature-resistant heterotrophic nitrification-aerobic denitrifying Pseudomonas and its application, wherein the strain is Pseudomonas sp. SW1, which is deposited in the China Center for Type Culture Collection (CCTCC), address: Wuhan University, Wuhan, China, the deposit date is November 14, 2022, the deposit number is CCTCC NO: M 20221797, and the strain was identified as being in an active state on November 21, 2022.

[0030] The present invention also provides an application of low-temperature resistant heterotrophic nitrification-aerobic denitrification Pseudomonas to remove ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in sewage under low temperature environment: Pseudomonas SW1 is put into sewage to be treated to remove inorganic nitrogen pollutants in the water, the OD600 value of the bacterial agent is 0.01±0.001, the water temperature of the sewage is not less than 4°C, the pH value is 5-11, the C / N ratio is 9-15, and the dissolved oxygen content is 2-8mg / L. The inorganic nitrogen is one or more of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen.

[0031] The present invention is further explained by the following examples, but they are not intended to limit the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0032] 1. 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 100mL of rural domestic sewage sample in a 250ml conical flask, add NH4Cl to the sample to make the concentration of nitrate and ammonia nitrogen 30mg / L, screen and acclimate, seal with sealing film to ensure aerobic conditions in the metabolic process, and place the conical flask in a constant temperature shaking shaker at 10℃ and 150r / min to culture, and monitor the concentration of ammonia nitrogen. When the concentration of ammonia nitrogen cannot be detected, inoculate 10mL of enrichment solution in a 250mL conical flask containing 100mL of enrichment culture medium and continue the above culture method.

[0035] After five consecutive transfers, the enriched culture was diluted and spread on a solid culture medium. After culturing at 10°C until colonies were visible to the naked eye, a single colony was picked out for plate streaking isolation. After five rounds of streaking, a pure strain was isolated.

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

[0038] The solid culture medium is a liquid culture medium with 1-2% agar powder added by mass.

[0039] (2) Identification of bacterial species

[0040] 1. Bacterial morphology observation

[0041] The strain was cultured at 10°C and 150 r / min to the logarithmic phase. The bacterial solution was diluted and evenly spread on a solid plate and cultured in a biochemical incubator at 10°C. After a single colony was formed on the plate, it was observed and subjected to Gram staining microscopy.

[0042] 2. Colony morphology

[0043] The colony is light yellow, round, with a protrusion in the middle, a smooth surface, slightly moist, and sticky when picked up. It is Gram-negative, with short rod-shaped cells, and a single cell is 2.5-3.5μm long and 0.8-1.2μm wide (see Figure 1 ).

[0044] 3. Molecular Identification of Strain

[0045] The bacterial genome was used as the DNA template and 27F (5'-AGAGTTTGATCCTGGCTCAG-3') and 1492R (5'-GGTTACCTTGTTACGACTT-3') were used as upstream and downstream primers for 16S rRNA amplification.

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

[0047] The effective length of the amplified strain 16S rDNA gene was about 1443bp nucleotide sequence, and the 16S rDNA sequence was shown in SEQ ID NO: 1. The sequence was entered into GenBank and compared with the database sequence using Blast software. The results showed that the similarity with the 16S rDNA sequence of Pseudomonas sp. was high, at 100%. Based on the phylogenetic analysis results of the 16SrDNA gene and the physiological and biochemical characteristics, it was identified as a new strain of Pseudomonas sp. and named SW1 (hereinafter referred to as "strain SW1"); and the strain was deposited in the China Center for Type Culture Collection, with the deposit number: CCTCC M 20221797.

[0048] 2. Test of 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) inoculating Pseudomonas SW1 strain into liquid culture medium and culturing to logarithmic growth phase, removing supernatant from the obtained bacterial suspension by centrifugation, washing with sterile saline to obtain Pseudomonas strain SW1 mother liquor; (2) preparing liquid culture medium, sterilizing the liquid culture medium in an autoclave at 103.4 kPa and 121° C. for 20 min, and cooling to room temperature; (3) adding Pseudomonas strain SW1 mother liquor to the cooled culture medium, performing fermentation culture, and obtaining Pseudomonas SW1 liquid bacterial suspension (OD600≈0.01).

[0051] Ammonia nitrogen, nitrate nitrogen, and nitrite nitrogen were used as the sole nitrogen source, respectively, and the inoculation ratio of C / N=10 and 1% (volume ratio) was 1% to inoculate the strain SW1 into a 250ml triangular flask containing 100mL of the above liquid culture medium, and the bacterial suspension of the strain SW1 (OD600≈0.01) was inoculated, and cultured in a 10°C incubator. During the culture process, the shaking speed was set to 150r / min. In addition, samples were taken every 6 hours during the culture process to detect the ammonia nitrogen concentration and total nitrogen concentration of the culture solution. The results are as follows: Figures 2 to 4 shown.

[0052] Depend on Figures 2 to 4It can be seen that when ammonia nitrogen is the only nitrogen source, the removal rate of ammonia nitrogen by strain SW1 can reach 99.98%, and the removal rate of total nitrogen by strain SW1 can reach 59.46% (see Figure 2 When nitrate nitrogen was the only nitrogen source, the removal rate of nitrate nitrogen by strain SW1 could reach 97.65%, and the removal rate of total nitrogen by strain SW1 could reach 59.16% (see Figure 3 When nitrite nitrogen was the only nitrogen source, the removal rate of nitrite nitrogen by strain SW1 was 78.10%, and the removal rate of total nitrogen by strain SW1 was 47.74% (see Figure 4 ). This shows that the strain SW1 of the present invention can remove ammonia nitrogen, nitrate nitrogen and nitrite nitrogen, and has a wide range of application scenarios.

[0053] 3. Optimization of culture conditions of strain SW1

[0054] (1) Heterotrophic nitrification-aerobic denitrification effect of strain SW1 at different pH values

[0055] The bacterial suspension of strain SW1 (OD600≈0.01) was inoculated into a 250ml triangular flask containing 100mL of the above culture medium at a 1% (volume ratio) inoculation ratio, and cultured at different pH values ​​(5, 7, 9, 10, 11). The shaking speed during the culture was set to 150r / min. The initial ammonia nitrogen was set at 30mg / L and cultured for 30h. During this period, the ammonia nitrogen concentration and total nitrogen concentration of the 30h culture solution were sampled and measured. The results are shown in Figure 5 .

[0056] like Figure 5 As shown in the figure, when the pH is 5, 41.95% of the ammonia nitrogen in the culture solution is still removed. When the pH is 7 and 9, the strain SW1 can remove more than 99.48% of the ammonia nitrogen, and the removal rate of total nitrogen can reach about 70%. When the pH is 10, the removal rate of ammonia nitrogen by strain SW1 is 83.06%, and the removal rate of total nitrogen is 52.31%. When the pH is 11, 73.54% of the ammonia nitrogen in the culture solution is still removed, indicating that the strain SW1 can tolerate the strong alkalinity of pH 10-11, and has certain application prospects in the treatment of strong alkaline wastewater (such as printing and dyeing wastewater).

[0057] (2) Denitrification effect of strain SW1 under different temperatures by anaerobic nitrification and aerobic denitrification

[0058] The bacterial suspension of strain SW1 (OD600≈0.01) was inoculated into a 250ml triangular flask containing 100mL of the above culture medium at a 1% (volume ratio) inoculation ratio, and cultured in incubators at different temperatures (4°C, 10°C, 20°C, 30°C, 40°C). During the culture process, the rotation speed was set to 150r / min, the initial ammonia nitrogen was set to 30mg / L, and the culture was carried out for 30h. During this period, the ammonia nitrogen concentration and total nitrogen concentration of the 30h culture solution were sampled and measured. The results are shown in Figure 6 .

[0059] like Figure 6 As shown in the figure, strain SW1 can metabolize 44.75% of ammonia nitrogen in a 4℃ environment. When the temperature rises to 10℃ and the culture is carried out for 30h, the removal rate of ammonia nitrogen by strain SW1 can reach 99.71%, and the removal rate of total nitrogen can reach 72.13%. When the temperature is further increased to 40℃, the removal rate of ammonia nitrogen by strain SW1 decreases, but it can still reach 97.38%.

[0060] This shows that the strain SW1 can adapt to the water environment of 4-40℃, and its nitrogen removal ability is stronger at 10-40℃.

[0061] (3) Denitrification effect of strain SW1 under different carbon sources by anaerobic nitrification and aerobic denitrification

[0062] As an electron donor, carbon source can provide metabolic energy for bacterial growth. At the same time, as an indispensable part of the sewage treatment process, carbon source is a key environmental factor in the aerobic denitrification process. Sucrose, glucose, citrate, acetate and succinate were selected as carbon sources to explore the nitrogen metabolism efficiency of strain SW1. The bacterial suspension of strain SW1 (OD600≈0.01) was inoculated into a 250mL triangular flask containing 100mL of the above culture medium at a 1% inoculation ratio. The culture temperature was 10°C, the speed was set to 150r / min during the culture process, the initial ammonia nitrogen was set to 30mg / L, and the culture was carried out for 30h. During this period, the ammonia nitrogen concentration and total nitrogen concentration of the 30h culture solution were sampled and measured. The results are shown in Figure 7 .

[0063] like Figure 7 As shown in the figure, when sucrose is the only carbon source, the ammonia nitrogen removal rate of strain SW1 can reach 42.29%. When acetate, citrate and succinate are used as carbon sources, the ammonia nitrogen removal rate of strain SW1 is above 99.45%, and the total nitrogen removal rate is 66.34%, 74.41% and 58.56% respectively. When glucose is the only carbon source, the ammonia nitrogen removal rate of strain SW1 is only 20.36%. This shows that the nitrogen removal ability of strain SW1 can be improved when acetate, citrate and succinate are used as carbon sources.

[0064] (4) Denitrification effect of strain SW1 under different C / N ratios

[0065] The bacterial suspension of strain SW1 (OD600≈0.01) was inoculated into a 250mL triangular flask containing 100mL of the above culture medium at a 1% inoculation ratio and cultured at different C / N ratios (3, 6, 9, 12, 15). During the culture process, the temperature was set at 10°C, the initial ammonia nitrogen was set at 30mg / L, and the culture was carried out for 30h. During this period, the ammonia nitrogen concentration and total nitrogen concentration of the 30h culture solution were sampled and measured. The results are shown in Figure 8 .

[0066] like Figure 8 As shown in the figure, 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 from 78.31%.

[0067] This shows that the strain SW1 can adapt to the water environment with a C / N ratio of 3-15, and its nitrogen removal ability is stronger when the C / N ratio is 9-15.

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

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

[0070] Table 1 Independent variables and level coding values

[0071]

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

[0073] Table 2 Experimental design and results

[0074] Serial number C / N Temperature(℃) 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 the conditions of C / N ratio of 6-15, temperature of 10-40℃, and pH of 7-11. It has the ability to tolerate strong alkali with a pH of 10-11 in an environment of 10℃, and can be used for strong alkaline wastewater treatment under low temperature conditions in northern winter.

[0076] Construction and feasibility analysis of heterotrophic nitrification model: The test results were analyzed on Design-Expert software, and the relationship between the quadratic polynomial fitting factors (C / N, temperature, pH) and the response value (total nitrogen removal rate) was obtained to obtain the equation:

[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 ANOVA variance homogeneity test was used to study the effects of each factor and interaction on the response value (total nitrogen removal rate) and verify the degree of fit of the coded value equation. The results are shown in Table 3:

[0079] Table 3 Analysis of variance for response surface design of strain SW1

[0080] factor sum of squares Degrees of Freedom Mean Square F-number 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. The larger the F value and the smaller the P value, the stronger the significance of the model. As shown in Table 3, the P value of this experimental model is less than 0.001, indicating that the model equation is significant; the lack of fit term is an important data used to evaluate the reliability of the equation. If it is significant, it means that the equation simulation is not good and needs to be adjusted; if it is not significant, it means that the equation simulation is good. The lack of fit term of this fitting model is 0.1251>0.01, indicating that the model is not significant at the 0.01 level, the lack of fit term and pure error are not significant, the model fits well, and the experiment has good stability.

[0082] The response surface methodology was used to study the effects of C / N ratio, temperature and pH on the nitrification and denitrification capacity of strain SW1 and the interaction between the three factors. Figure 9-11 .

[0083] Figure 9-11 It can be seen that the influence of the three factors on the total nitrogen removal rate of strain SW1 is ranked from large to small: initial pH value > temperature > carbon-nitrogen ratio. The optimal conditions for heterotrophic nitrification and denitrification of strain SW1 are: carbon-nitrogen ratio of 8.924, pH value of 7.909, and temperature of 22.766℃, with the highest total nitrogen removal rate of 72.232%. Through F test, P value, lack of fit analysis and verification test under optimal conditions, it is proved that the model is effective and reliable in predicting the influence of various factors on the heterotrophic nitrification TN removal rate of strain SW1.

[0084] IV. Application test of strains in domestic sewage in Example 1

[0085] 50L of domestic wastewater was collected from the water inlet of a domestic sewage treatment system in Wuhan, Hubei. The initial water quality parameters of the wastewater were: ammonia nitrogen 38mg / L, total nitrogen 44mg / L, COD 454mg / L, pH=7.6, and salinity 0.1%. The wastewater was divided into 6 plastic cups with a volume of 8L, 3 of which were added with 1% (volume ratio) bacterial suspension of strain SW1 (OD600≈0.01), and the other 3 were used as control groups; all barrels were placed in a 10℃ incubator for culture, and air was introduced with an aerator, with a dissolved oxygen content of 5mg / L; during the test, the changes in the ammonia nitrogen, total nitrogen, and COD content of the system were regularly tested, and the aerobic nitrification, denitrification and denitrification capabilities of the strains were analyzed. The results are shown in Fig.12 .

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

[0087] Example 2 Application test of strains in printing and dyeing wastewater

[0088] 25L of printing and dyeing wastewater was collected from the water inlet of the sewage treatment system of a printing and dyeing factory in Jiaxing. The effluent water quality of the wastewater was 67mg / L ammonia nitrogen, 93mg / L total nitrogen, 2100mg / L COD, pH 10.3, and 1.4% salinity. The wastewater was divided into 6 plastic cups with a volume of 5L, 3 of which were added with 5% bacterial suspension of strain SW1 (OD600≈0.01), and the other 3 were used as control groups; all barrels were placed in a 10℃ incubator for culture, and air was introduced with an aerator, with a dissolved oxygen content of 5mg / L; during the test, the changes in the ammonia nitrogen, total nitrogen, and COD content of the system were regularly detected, and the aerobic nitrification, denitrification and denitrification capabilities of the strains were analyzed. The results are shown in the figure. Fig.13 .

[0089] Fig.13 As shown, the removal rate of ammonia nitrogen in the bacteria-added group can reach 86.27%, and the removal rate of total nitrogen can reach 50.93%, while the ammonia nitrogen and total nitrogen in the control group are almost unchanged, and the denitrification efficiency of strain SW1 in printing and dyeing wastewater is very significant. This shows that the strain SW1 of the present invention exhibits good 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 in the protection scope of the present invention.

Claims

1. A low temperature resistant heterotrophic nitrification-aerobic denitrification Pseudomonas, characterized by: The strain is Pseudomonas sp. SW1, and its deposit number is CCTCC NO: M 20221797.

2. Use of the low-temperature-resistant heterotrophic nitrification-aerobic denitrifying Pseudomonas as described in claim 1 to remove inorganic nitrogen pollutants in sewage under a low-temperature environment.

3. The use according to claim 2, characterized in that: The water temperature of the sewage is not less than 4°C.

4. The use according to claim 2, characterized in that: The pH value of the sewage is 5-11.

5. The use according to claim 2, characterized in that: The dissolved oxygen content in the sewage is 2-8 mg / L.

6. The use according to claim 2, characterized in that: The inorganic nitrogen is one or more of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen.

7. The use according to claim 2, characterized in that: Pseudomonas SW1 was added to the sewage to be treated to remove inorganic nitrogen pollutants in 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: The invention comprises the Pseudomonas sp. SW1 described in claim 1.

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