Paracoccus denitrificans and application thereof

Abstract

The invention relates to the technical field of microbial denitrification, and discloses paracoccus denitrificans and application thereof. The paracoccus denitrificans is named as 392A9 and is preserved in the China General Microbiological Culture Collection Center on October 20, 2023, the preservation number of the paracoccus denitrificans is CGMCC No.28691, and the classification of the microorganisms of the paracoccus denitrificans is named as paracoccus denitrificans. The paracoccus denitrificans 392A9 provided by the invention can survive and realize efficient denitrification under aerobic and anaerobic conditions and higher nitrate concentration, and can adapt to a wider pH (Potential of Hydrogen) range, so that the paracoccus denitrificans 392A9 has a better application prospect in denitrification treatment of nitrate wastewater.

Description

Technical Field

[0001] The present invention relates to the technical field of microbial denitrification, and particularly to a Paracoccus denitrificans and its application. Background Art

[0002] Nitrate is one of the common pollutants in environmental water bodies. When the nitrate concentration in water bodies is too high, it will cause water eutrophication, damage the aquatic ecological environment, and also endanger the health of animals and humans. For example, after being ingested by the human body, it will cause diseases such as liver damage, skin cyanosis, methemoglobinemia, and cancer. The main sources of nitrate in environmental water bodies are nitrate wastewater discharged from industry, agriculture, and daily life, such as solid-liquid landfill leachate, kitchen waste and fecal wastewater, nitrogen-containing chemical synthesis wastewater, etc. Therefore, denitrification treatment of nitrate wastewater is of great significance for preventing and controlling NO3 - -N pollution in environmental water bodies.

[0003] The denitrification methods of nitrate wastewater mainly include biological methods, physicochemical methods (ion exchange, reverse osmosis, electrodialysis, adsorption), and catalytic reduction methods (photocatalysis, liquid-phase catalytic reduction, electrocatalysis). Among them, the biological method uses the metabolism of microorganisms to convert nitrate into nitrogen gas, which has the advantages of no secondary pollution, high treatment efficiency, and simple operation, and is currently a widely used nitrate removal method.

[0004] Paracoccus denitrificans has been reported to be able to remove nitrate, but the nitrate concentrations that the currently reported strains can tolerate and effectively treat are all relatively low. For example, Patent CN202310181646.3 discloses a Paracoccus denitrificans and its application, in which the reported Paracoccus denitrificans HY-1 can grow in a medium with a nitrate concentration of 0.72 g / L, and can achieve effective denitrification of water bodies with an initial nitrate concentration of 213.76 mg / L under aerobic conditions and an initial nitrate concentration of 453.74 mg / L under anaerobic conditions. Summary of the Invention

[0005] In order to solve the above technical problems, that is, the nitrate concentrations that the currently reported strains within the species Paracoccus denitrificans can tolerate and effectively treat are all relatively low, the present invention provides a Paracoccus denitrificans and its application. The Paracoccus denitrificans 392A9 provided by the present invention can survive and achieve efficient denitrification under aerobic and anaerobic conditions and at relatively high nitrate concentrations, and can adapt to a wide pH range, so it has good application prospects in the denitrification treatment of nitrate wastewater.

[0006] The specific technical solution of the present invention is as follows: In a first aspect, the present invention provides a Paracoccus denitrificans strain named 392A9, which was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on October 20, 2023. The address of the depositary institution is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 28691. The microbial taxonomic name is Paracoccus denitrificans.

[0007] The Paracoccus denitrificans 392A9 of the present invention can survive and achieve efficient denitrification under aerobic and anaerobic conditions when the nitrate (NO3 - -N) concentration is 10,000 mg / L. Through experiments, when the initial nitrate concentration is 10,000 mg / L, the denitrification rate (TN removal rate) of this strain can reach 99.5% within 9 days under aerobic conditions and 98.9% within 15 days under anaerobic conditions. Since it can tolerate and effectively treat a relatively high nitrate concentration, the strain 392A9 of the present invention can directly treat high-concentration nitrate wastewater without the need to pre-dilute the wastewater or use physical and chemical methods to reduce the nitrate content.

[0008] The aerobic process requires oxygen supply and consumes more electricity, that is, more electricity costs, but it is relatively safe. The anaerobic process does not require oxygen and only needs stirring, consuming less electricity, but there are safety risks. The Paracoccus denitrificans 392A9 of the present invention has a high nitrate removal ability under both aerobic and anaerobic conditions, so the anaerobic and aerobic processes can be flexibly selected according to different needs, or the anaerobic and aerobic processes can be used in combination, and this strain can be used in both the anaerobic section and the aerobic section at the same time.

[0009] In addition, the Paracoccus denitrificans 392A9 of the present invention can adapt to a relatively wide pH range. Through experiments, under both aerobic and anaerobic conditions, this strain can survive and remove nitrate in the water body in an environment with a pH of 5.0 - 9.0. Therefore, when using this strain to treat nitrate wastewater, the process of pre-adjusting the pH of the wastewater can be simplified, the use of pH adjustment reagents can be reduced, and the wastewater treatment cost can be lowered.

[0010] In a second aspect, the present invention provides a microbial agent containing the Paracoccus denitrificans.

[0011] Preferably, the microbial agent also contains a culture medium.

[0012] Preferably, the agent is a bacterial liquid, a solid bacterial agent or activated sludge.

[0013] In a third aspect, the present invention provides the application of the Paracoccus denitrificans or the microbial agent in the aerobic denitrification treatment of nitrate wastewater.

[0014] Preferably, the application includes the following steps: adding the Paracoccus denitrificans or the microbial inoculum to nitrate wastewater for aerobic denitrification.

[0015] Preferably, during the aerobic denitrification process, the dissolved oxygen concentration in the wastewater is controlled to be not lower than 2.0 mg / L.

[0016] Fourthly, the present invention provides the application of the Paracoccus denitrificans or the microbial inoculum in the anaerobic denitrification treatment of nitrate wastewater.

[0017] Preferably, the application includes the following steps: adding the Paracoccus denitrificans or the microbial inoculum to nitrate wastewater for anaerobic denitrification.

[0018] Preferably, during the anaerobic denitrification process, the dissolved oxygen concentration in the wastewater is controlled to be not higher than 0.5 mg / L.

[0019] Compared with the prior art, the present invention has the following advantages: (1) The Paracoccus denitrificans 392A9 of the present invention can tolerate and effectively treat up to 10,000 mg / L of nitrate (NO3 - -N) under aerobic and anaerobic conditions. Currently, within the species Paracoccus deoxidans, no strain has been reported to have the tolerance and treatment ability for high-concentration nitrate comparable to that of the strain of the present invention.

[0020] (2) The Paracoccus denitrificans 392A9 of the present invention has good nitrate removal ability under both aerobic and anaerobic conditions, and thus can meet different process requirements.

[0021] (3) The Paracoccus denitrificans 392A9 of the present invention can adapt to a relatively wide pH range and can survive and remove nitrate in water within the pH range of 5.0 - 9.0 under both anaerobic and aerobic conditions. Description of the Drawings

[0022] Figure 1 shows the influence of the influent pH on the aerobic denitrification effect of strain 392A9; Figure 2 is the aerobic continuous influent and effluent test device used in Example 4; Figure 3 is the anaerobic continuous influent and effluent test device used in Example 5; Figure 4 shows the influence of the glucose addition amount in the influent on the aerobic denitrification effect of strain 392A9; Figure 5 shows the influence of HRT on the aerobic denitrification effect of strain 392A9; Figure 6Effect of influent pH on anaerobic denitrification performance of strain 392A9; Figure 7 Effect of glucose addition amount in influent on anaerobic denitrification performance of strain 392A9; Figure 8 Effect of HRT on anaerobic denitrification performance of strain 392A9. Specific implementation manners

[0023] The present invention will be further described below in conjunction with embodiments.

[0024] General embodiment A Paracoccus denitrificans strain, named 392A9, was deposited on October 20, 2023 at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms. The address of the depositary institution is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit number is CGMCC No. 28691, and the microbial taxonomic name is Paracoccus denitrificans.

[0025] A microbial inoculum containing the above-mentioned Paracoccus denitrificans.

[0026] As a specific implementation manner, the microbial inoculum further contains a culture medium.

[0027] As a specific implementation manner, the inoculum is a bacterial solution, a solid inoculum or activated sludge.

[0028] Application of the above-mentioned Paracoccus denitrificans or the above-mentioned microbial inoculum in aerobic denitrification treatment of nitrate wastewater.

[0029] As a specific implementation manner, the application includes the following steps: adding the Paracoccus denitrificans or the microbial inoculum to nitrate wastewater for aerobic denitrification.

[0030] As a specific implementation manner, during the aerobic denitrification process, the dissolved oxygen concentration in the wastewater is controlled to be not lower than 2.0 mg / L.

[0031] Application of the above-mentioned Paracoccus denitrificans or the above-mentioned microbial inoculum in anaerobic denitrification treatment of nitrate wastewater.

[0032] As a specific implementation manner, the application includes the following steps: adding the Paracoccus denitrificans or the microbial inoculum to nitrate wastewater for anaerobic denitrification.

[0033] As a specific implementation manner, during the anaerobic denitrification process, the dissolved oxygen concentration in the wastewater is controlled to be not higher than 0.5 mg / L.

[0034] The following examples aim to further introduce and demonstrate the objectives, technical solutions, and technical effects of the present invention. Therefore, the examples should be understood as only used to more detailedly demonstrate the present invention, rather than limiting the content of the present invention in any way. The raw materials used in the examples can be obtained from conventional commercial channels without special instructions, and the methods used are conventional methods in the art without special instructions. The strain 392A9 mentioned in the following examples all refers to Paracoccus denitrificans 392A9 with the preservation number of CGMCC No. 28691.

[0035] Example 1: Preparation of wastewater 1.1 Source and quality of wastewater The wastewater is a high-nitrate wastewater from a new material in Hubei, and its main component is sodium nitrate. The water quality of the wastewater is shown in Table 1.

[0036] Table 1 Water quality of wastewater Index Unit Value COD mg / L 80364 TOC mg / L 41391 <![CDATA[NH3-N]]> mg / L 0 TP mg / L 5 <![CDATA[NO2 - -N]]> mg / L 0 <![CDATA[NO3 - -N]]> mg / L 10000 TN mg / L 10000 TDS ％ 1.20 pH / 5 1.2 Nutrient preparation of wastewater KH2PO4 0.5 g / L was added to the above wastewater, and the pH was adjusted to 7.0 with NaOH.

[0037] Example 2: Preparation of culture medium The preparation methods of the culture media used in the following examples are as follows: (1) Wastewater liquid medium: The wastewater after nutrient preparation in Example 1 was filtered and sterilized with a sterile 0.22 μm filter membrane.

[0038] (2) Wastewater solid medium: Solution A: The wastewater after nutrient preparation in Example 1 was filtered and sterilized with a sterile 0.22 μm filter membrane.

[0039] Solution B: 4% agar solution was prepared with distilled water and sterilized at 121 °C for 20 min.

[0040] Solution A and Solution B were mixed at a ratio of 1:1 (v / v) and then introduced into a sterile petri dish to obtain the wastewater solid separation medium.

[0041] (3) LB medium: Yeast extract 5 g / L, tryptone 10 g / L, NaCl 10 g / L, natural pH. Sterilized at 121 °C for 20 min.

[0042] (4) RM nutrient solution: 10 mL of crude Rpf extract, 0.3 g / L of MgSO4·7H2O, 0.2 g / L of MnSO4·H2O, 0.2 g / L of CaCl2, 0.2 g / L of FeSO4·7H2O, 0.008 g / L of Na2MoO4·2H2O, 0.006 g / L of CuSO4·5H2O, 0.009 g / L of ZnSO4·7H2O, 0.0001 g / L of CoCl2·6H2O, 0.015 g / L of H3BO3, pH = 6. For the preparation method of the crude Rpf extract, refer to Patent ZL202211094469.7, a complex for promoting the separation and cultivation of anaerobic microorganisms and its application.

[0043] Example 3: Screening and identification of strains 3.1 Primary screening of strains The strains are sourced from the pharmaceutical and chemical industrial source strain library (containing more than 6,000 strains) accumulated by the research team of this invention through long-term scientific research. The strains in this library are all isolated from pharmaceutical and chemical related samples (such as wastewater, soil, PBR biological pretreatment system, activated sludge system, etc.).

[0044] According to the wastewater characteristics and strain isolation sources, 2,000 strains in the library were selected for screening. The strains were activated in 96-well plates filled with LB medium. After 2 days of cultivation, each bacterial solution was inoculated into 96-well plates filled with wastewater liquid medium (containing NO3 - -N 5000 mg / L) at an inoculation amount of 1%. The system was placed in a micro oscillator and cultured at 30 °C. An enzyme-labeled instrument was used to select strains with OD 600 > 0.5 within 3 days to screen for strains with high nitrate resistance, and they were used as the re-screened strains I.

[0045] Result: A total of 8 re-screened strains I were obtained.

[0046] 3.2 Re-screening of strains After the above re-screened strains I were activated in LB medium for 2 days, each bacterial solution was inoculated into test tubes filled with 3 mL of wastewater liquid medium diluted 4 times (containing NO3 - -N 2500 mg / L) at an inoculation amount of 1%. The system was placed in a shaker at 150 r / min and cultured at 30 °C. A nitrate nitrogen test paper was used to evaluate the content of NO3 - -N in the system. Strains with a NO3 - -N removal rate ≥ 50% within 5 days were selected, and the strains were repeatedly streaked on the wastewater solid medium to obtain strains that could grow stably on the wastewater as the re-screened strains II.

[0047] Result: One re-screened strain II was obtained, named 392A9.

[0048] 3.3 Strain identification The genomic DNA of strain 392A9 was extracted using a genomic DNA extraction kit, and 16S rDNA was amplified by PCR and sequenced for molecular biological identification. The upstream primer and downstream primer used for PCR amplification were as follows: Upstream primer 27F: 5'-GAGAGTTTGATCMTGGCTCAG-3' Downstream primer 1492R: 5′-TACGGYTACCTTGTTACGAC-3′ The purification and sequencing of the PCR product were both completed by Sangon Biotech (Shanghai) Co., Ltd. The obtained 16S rDNA sequence of the strain was compared in the EzBioCloud database. The results showed that this strain belonged to Paracoccus denitrificans, so it was named Paracoccus denitrificans 392A9.

[0049] Example 4: Denitrification effect of strain 392A9 under aerobic conditions 4.1 Test device The test device was a continuous inflow and outflow device, which simulated the on-site treatment system to the greatest extent to test the treatment effect of the strain on high-nitrate wastewater. The whole set of devices was composed of an influent tank, a strain tank, and an effluent tank connected in sequence as shown in Figure 2 . The effective volume of each tank was 3 L. The influent tank was used to supplement nutrients and accommodate wastewater, and a stirring system was installed at the bottom. The strain treatment tank was a biochemical treatment tank for strains, and an aeration system was installed at the bottom. The wastewater in the influent tank was lifted to the strain tank by a peristaltic pump; the effluent tank was used to collect the treated wastewater.

[0050] 4.2 Influent The influent was the wastewater without nutrient adjustment in Example 1, and KH2PO4 0.5 g / L, RM nutrient solution 1 mL / L, and a certain amount of glucose were added, and the pH was adjusted to a certain value.

[0051] 4.3 Adding strains Strain 392A9 was cultured on LB solid medium at 30 °C for 2 d. Single colonies were picked and inoculated into LB liquid medium, and cultured at 150 r / min and 30 °C until the logarithmic phase to obtain the seed liquid of strain 392A9.

[0052] RM nutrient solution 1 mL / L was added to the strain tank, and the starting pH of the strain tank system was adjusted to 7.0. The seed liquid of strain 392A9 was inoculated into the strain treatment tank at an inoculation amount of 10%.

[0053] 4.4 Influence of influent pH on aerobic denitrification effect No additional glucose is added to the influent. The DO in the strain pool is controlled at ≥2.0 mg / L, and the water temperature is 25 - 30°C. The influent pH is set at 5.0, 6.0, 7.0, 8.0, and 9.0 respectively. Check the treatment effect of the strain on the wastewater within 10 days of the HRT in the strain pool. The results are shown in Figure 1 . Figure 1 In Figure 1 , the denitrification rate is the TN removal rate.

[0054] The results show that when the influent pH is adjusted between 5.0 and 6.0, the denitrification rate reaches 50% in both cases. Then, as the influent pH increases, the denitrification rate gradually decreases. It is speculated that the reason is as follows: In the aerobic denitrification reaction stage, the pH of the strain pool system shows an upward trend. The higher the influent pH, the higher the pH of the strain pool system. For example, when the influent pH is 5.0, the pH of the strain pool finally stabilizes at about 9.0; while when the influent pH is 9.0, the pH of the strain pool system is as high as 11.0, and the extremely high pH of the system inhibits the growth and metabolism of the strain.

[0055] Conclusion: Strain 392A9 can perform aerobic denitrification within the range of influent pH 5.0 - 9.0. The influent pH should be controlled between 5.0 and 6.0, and the optimal value is 5.0.

[0056] 4.5 Influence of carbon source dosage on aerobic denitrification effect The influent pH is adjusted to 5.0. The DO in the strain pool is controlled at ≥2.0 mg / L, and the water temperature is 25 - 30°C. The influent glucose addition amounts are set at 0, 5 g / L, 10 g / L, and 15 g / L respectively. Check the treatment effect of the strain on the wastewater within 10 days of the HRT in the strain pool. The results are shown in Figure 4 . Figure 4 In Figure 4 , the denitrification rate is the TN removal rate.

[0057] The results show that when additional glucose is supplemented to the influent, the promoting effect on the denitrification rate is obvious. As the amount of glucose gradually increases, the denitrification rate also increases. However, when the glucose addition amount is 15 - 20 g / L, the denitrification rate reaches the highest at about 99.5%.

[0058] Conclusion: Strain 392A9 can perform aerobic denitrification without adding external glucose. The addition of glucose can improve its denitrification effect. The glucose addition amount in the influent should be controlled between 15 - 20 g / L, and the optimal value is 15 g / L.

[0059] 4.6 Influence of HRT on aerobic denitrification effect The influent pH is adjusted to 5.0, and 15 g / L of glucose is added additionally. The DO in the strain pool is controlled at ≥2.0 mg / L, and the water temperature is 25 - 30°C. Check the influence of different HRTs (5 d, 6 d, 7 d, 8 d, 9 d, 10 d) in the strain pool on the treatment effect of the strain. The results are shown in Figure 5 . Figure 5 In Figure 5 , the denitrification rate is the TN removal rate.

[0060] The results showed that: within the range of 5 - 10 d of HRT, as the HRT was extended, the denitrification rate gradually increased, and reached the maximum denitrification rate of 99.5% at 9 d of HRT.

[0061] Conclusion: The optimal HRT of the strain 392A9 for aerobic denitrification in the strain pool is 9 d.

[0062] 4.7 Aerobic wastewater treatment effect under the optimal conditions The influent pH was adjusted to 5.0, 15 g / L of glucose was additionally added, the DO in the strain pool was controlled ≥ 2.0 mg / L, and the water temperature was 25 - 30 °C. The treatment effect of the strain on the wastewater within 9 d of the HRT in the strain pool was observed. The results are shown in Table 2.

[0063] Table 2 Aerobic process treatment effect of strain 392A9 on high - nitrate wastewater Influent Effluent Removal Rate Volumetric Loading HRT Unit mg / L mg / L ％ <![CDATA[kg / (m 3 ·d)]]> d COD 98567 9810 90.0 9.9 9 TOC 54754 5436 90.1 5.5 9 <![CDATA[NO3 - -N]]> 10000 55 99.5 1.1 9 TN 10000 55 99.5 1.1 9 Note: In Table 2, the influent COD and TOC of the wastewater are the data after adding glucose.

[0064] The results showed that: Strain 392A9 can directly treat wastewater with a nitrate - nitrogen concentration of up to 10000 mg / L, and achieve a denitrification rate of 99.5% and a denitrification volume load of 1.1 kg / (m 3 ·d) at 9 d of HRT, and simultaneously achieve efficient removal of wastewater COD and TOC, with a removal rate of about 90%. During aerobic denitrification, the required TOC / TN is about 5.0 and COD / TN is about 8.9.

[0065] Example 5: Denitrification effect of strain 392A9 under anaerobic conditions 5.1 Test device The test device is a continuous influent and effluent device, which simulates the on - site treatment system to the greatest extent to test the treatment effect of the strain on high - nitrate wastewater. The whole set of device is Figure 3 as shown, and is composed of an influent pool, a strain pool and an effluent pool connected in sequence. The effective volume of each pool is 3 L. The influent pool is used to supplement nutrients and accommodate wastewater, and a stirring system is installed at the bottom. The strain treatment pool is a biochemical treatment pool for the strain, and a stirring system is installed at the bottom. The wastewater in the influent pool is lifted to the strain pool by a peristaltic pump; the effluent pool is used to collect the treated wastewater.

[0066] 5.2 Influent Same as Example 4.

[0067] 5.3 Adding strains Same as Example 4.

[0068] 5.4 Influence of influent pH on anaerobic denitrification effect No additional glucose is added to the influent. The DO in the strain pool is controlled at ≤ 0.5 mg / L, and the water temperature is 25 - 30 °C. The influent pH is set at 5.0, 6.0, 7.0, 8.0, and 9.0 respectively. Check the wastewater treatment effect of the strain in the strain pool within 10 days of HRT. The results are shown in Figure 6 . Figure 6 In Figure 6 , the denitrification rate is the TN removal rate.

[0069] The results show that when the influent pH is adjusted between 6.0 and 7.0, the denitrification rate reaches 50%, and the pH of the strain pool system is stable at about 9.0. When the influent pH is lower or higher, the denitrification rate decreases. Presumed reason: In the anaerobic denitrification reaction stage, when the influent pH is 5.0, the pH of the strain pool finally stabilizes at about 7.5; when the influent pH is 8.0 - 9.0, the pH of the strain pool system is as high as 10.0, and the ultra-high pH of the system inhibits the growth and metabolism of the strain.

[0070] Conclusion: Strain 392A9 can carry out anaerobic denitrification within the range of influent pH 5.0 - 9.0. The influent pH should be controlled between 6.0 and 7.0, and the optimal value is 6.0.

[0071] 5.5 Influence of carbon source dosage on anaerobic denitrification effect The influent pH is adjusted to 6.0. The DO in the strain pool is controlled at ≤ 0.5 mg / L, and the water temperature is 25 - 30 °C. The glucose addition amounts in the influent are set at 0, 1 g / L, 3 g / L, 5 g / L, and 10 g / L respectively. Check the wastewater treatment effect of the strain in the strain pool within 10 days of HRT. The results are shown in Figure 7 . Figure 7 In Figure 7 , the denitrification rate is the TN removal rate.

[0072] The results show that when glucose is additionally supplemented to the influent, the promoting effect on the denitrification rate is obvious, but when the glucose addition amount is 3 - 10 g / L, the denitrification rate reaches the highest at about 65%.

[0073] Conclusion: Strain 392A9 can carry out anaerobic denitrification without adding external glucose. The addition of glucose can improve its denitrification effect. The glucose addition amount in the influent should be controlled between 3 and 10 g / L, and the optimal value is 3 g / L.

[0074] 5.6 Influence of HRT on anaerobic denitrification effect The influent pH is adjusted to 6.0, and 3 g / L of glucose is additionally added. The DO in the strain pool is controlled at ≤ 0.5 mg / L, and the water temperature is 25 - 30 °C. Check the influence of different HRTs (5 d, 10 d, 15 d, 20 d) in the strain pool on the treatment effect of the strain. The results are shown in Figure 8 . Figure 8 In Figure 8 , the denitrification rate is the TN removal rate.

[0075] The results showed that: within the range of 5 - 10 days of HRT, with the extension of HRT, the denitrification rate gradually increased. When the HRT was 5 days, the denitrification rate was only 22.2%; when the HRT was 15 days, the maximum denitrification rate reached 98.9%. Further extending the HRT did not increase the denitrification rate any more.

[0076] Conclusion: The optimal HRT of the strain pool for anaerobic denitrification by strain 392A9 is 15 days.

[0077] 5.7 Anaerobic wastewater treatment effect under the optimal conditions Adjust the influent pH to 6.0, add an additional 3 g / L of glucose, control the DO in the strain pool ≤ 0.5 mg / L, and the water temperature at 25 - 30 °C. Observe the treatment effect of the strain on the wastewater within 15 days of HRT in the strain pool. The results are shown in Table 3.

[0078] Table 3 Treatment effect of strain 392A9 on high - nitrate wastewater by anaerobic process Influent Effluent Removal Rate Volumetric Loading HRT Unit mg / L mg / L ％ <![CDATA[kg / (m 3 ·d)]]> d COD 85364 20410 76.1 4.3 15 TOC 42796 9365 78.1 2.2 15 <![CDATA[NO3 - -N]]> 10000 106 98.9 0.7 15 TN 10000 106 98.9 0.7 15 Note: In Table 3, the influent COD and TOC of the wastewater are the data after adding glucose.

[0079] The results showed that: Strain 392A9 can directly treat wastewater with a nitrate - nitrogen concentration of up to 10000 mg / L, and within 15 days of HRT, the denitrification rate reaches 98.9%, and the denitrification volume load reaches 0.7 kg / (m 3 ·d), and simultaneously achieve efficient removal of wastewater COD and TOC, with a removal rate of about 75% or more. During anaerobic denitrification, the required TOC / TN is about 3.4 and COD / TN is about 6.6.

[0080] In the present invention, the raw materials and equipment used, unless otherwise specified, are common raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are conventional methods in the art.

[0081] The above - mentioned are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent transformations made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A Paracoccus denitrificans, characterized in that, The Paracoccus denitrificans is named 392A9, which was deposited in the China General Microbiological Culture Collection Center on October 20, 2023, with the deposit number of CGMCC No. 28691, and the microbial taxonomic name is Paracoccus denitrificans Paracoccus denitrificans .

2. A microbial inoculant, characterized in that, The microbial inoculant contains Paracoccus denitrificans as described in claim 1.

3. The microbial inoculant according to claim 2, wherein The microbial inoculant further contains a culture medium.

4. The microbial inoculum according to claim 2 or 3, characterized in that, The inoculant is a bacterial liquid, a solid inoculant or activated sludge.

5. Use of Paracoccus denitrificans as described in claim 1 or the microbial inoculant as described in any one of claims 2 to 4 in the aerobic denitrification treatment of nitrate wastewater.

6. The application according to claim 5, characterized in that, It includes the following steps: Adding the Paracoccus denitrificans or the microbial inoculant to nitrate wastewater for aerobic deammonification.

7. The application according to claim 5 or 6, characterized in that During the aerobic denitrification process, controlling the dissolved oxygen concentration in the wastewater to be not lower than 2.0 mg / L.

8. Use of Paracoccus denitrificans as described in claim 1 or the microbial inoculant as described in any one of claims 2 to 4 in the anaerobic denitrification treatment of nitrate wastewater.

9. The application according to claim 8, wherein It includes the following steps: Adding the Paracoccus denitrificans or the microbial inoculant to nitrate wastewater for anaerobic deammonification.

10. The application according to claim 8 or 9, characterized in that, During the aerobic denitrification process, controlling the dissolved oxygen concentration in the wastewater to be not higher than 0.5 mg / L.

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