A salt-tolerant heterotrophic nitrification and denitrification strain, its cultivation method and application

Abstract

The present invention relates to a salt-tolerant heterotrophic nitrifying and denitrifying bacterial strain, its cultivation method, and application. The strain addresses the technical problem of existing nitrifying and denitrifying bacteria inhibiting nitrification in the presence of a carbon source. The strain is named Pseudomonas stutzeri YXH-102 and is deposited with the General Microbiology Center of the China National Center for Microbiological Culture Collection under the accession number CGMCC No. 27688. The present invention can be used in the field of sewage denitrification treatment.

Description

Technical Field

[0001] The present invention relates to a strain and a culture method and application thereof, in particular to a salt-tolerant heterotrophic nitrification and denitrification strain and a culture method and application thereof. Background Art

[0002] Nitrogen pollution has become a major hidden danger to the safety of my country's surface water environment. Ammonia nitrogen pollution in water bodies not only causes a series of environmental problems such as eutrophication, but also threatens human health. Microorganisms convert NH4 + Converted to NO3 through nitrification - or NO2 - , and then NO3 - or NO2 - Through denitrification - Reduction to gaseous N 2 Release into the atmosphere is a key step in the entire nitrogen cycle of the earth and occupies an important position in the entire nitrogen cycle.

[0003] The traditional nitrification process involves nitrifying bacteria, which are autotrophic microorganisms that need to be cultivated under carbon-free or low-carbon conditions. Currently, large-scale cultivation is also a problem in the industry, which limits its application. In addition, sewage environments generally contain a certain concentration of carbon source (COD), which also causes nitrifying bacteria to be inhibited by COD in the environment, limiting its application conditions and processes.

[0004] Denitrification is a process in which organic carbon is used as an electron donor and nitrate or nitrite as an electron acceptor to carry out denitrification. Heterotrophic nitrifying denitrifiers are a type of microorganism that can grow using carbon sources while producing NH4 + Nitrification, and then use NO3 - or NO2 - Denitrifying microorganisms do not have the contradiction of inhibiting nitrification in the presence of carbon sources. Therefore, heterotrophic nitrifying and denitrifying microorganisms have shown great application prospects in the denitrification of polluted water bodies with their high efficiency and low cost advantages.

[0005] However, the growth, reproduction, and metabolic activities of different microorganisms are significantly affected by external environmental conditions, including temperature, pH, salinity, and nutrients. The growth and functional requirements of different microorganisms vary greatly. Therefore, obtaining, cultivating, and utilizing these microorganisms has become a pressing technical challenge. Summary of the Invention

[0006] The present invention aims to solve the technical problem that existing nitrifying and denitrifying bacteria inhibit nitrification in the presence of a carbon source, and provides a salt-tolerant heterotrophic nitrifying and denitrifying strain that can denitrify polluted water bodies with high efficiency and low cost, as well as a cultivation method and application thereof.

[0007] To this end, the present invention provides a heterotrophic nitrification and denitrification strain, which is named Pseudomonas stutzeri YXH-102; its preservation institution is the General Microbiology Center of China Microorganism Culture Collection Administration, and its preservation number is: CGMCC No.27688.

[0008] Preferably, the strain is cultured using a heterotrophic nitrification medium, wherein the formula of the heterotrophic nitrification medium is: ammonium chloride 1.0-3.0 g / L, sodium succinate 8.5 g / L, KH2PO4 1.0-1.5 g / L, MgSO4·7H2O 0.5-1.0 g / L, CaCl2·6H2O 0.2-2 g / L, FeCl3·6H2O 0.05-0.5 g / L, and sodium molybdate 0.015-0.02 g / L.

[0009] Preferably, the strain is cultured using a denitrification medium, wherein the formula of the denitrification medium is: KNO3 1.0-3.0 g / L, sodium succinate 8.5 g / L, KH2PO4 1.0-1.5 g / L, MgSO4·7H2O 0.5-1.0 g / L, CaCl2·6H2O 0.2-2 g / L, FeCl3·6H2O 0.05-0.5 g / L, and sodium molybdate 0.015-0.02 g / L.

[0010] The present invention also provides a use of a heterotrophic nitrification and denitrification strain as a component of a composite bacterial agent in the denitrification of low-temperature and high-concentration domestic sewage.

[0011] The strain is cultured using seeds and fermentation medium, wherein the components of the seeds and fermentation medium are as follows: 1.0 g / L KNO3, 10-20 g / L sucrose, 1.0-1.5 g / L KH2PO4, 0.5-1.0 g / L MgSO4·7H2O, 0.2-2 g / L CaCl2·6H2O, 0.05-0.5 g / L FeCl3·6H2O, and 0.015-0.02 g / L sodium molybdate; the fermentation liquid is inoculated into sewage at a volume ratio of 1 / 10,000 to 3 / 10,000.

[0012] The present invention also provides an application of a heterotrophic nitrification and denitrification strain in denitrification of high-salt and high-temperature wastewater.

[0013] The strain was cultured using a high-density fermentation medium containing 20 g / L peptone, 10-20 g / L sucrose, 1.5 g / L K2HPO4, and 1.5 g / L MgSO4·7H2O. The corresponding salt was added according to the salt content of the high-salt wastewater, with the concentration being 1 / 2 of the salt concentration of the high-salt wastewater.

[0014] The present invention has the following beneficial effects:

[0015] The strain provided by the present invention has the functions of heterotrophic aerobic nitrification and denitrification and anaerobic denitrification, and has a wide temperature and pH adaptability range; it provides a good microbial material for the biological denitrification treatment of low-temperature, high-temperature, high-salt, and high-ammonia nitrogen polluted water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the morphological characteristics of Pseudomonas stutzeri YXH-102 in culture medium provided by the present invention;

[0017] Figure 2 This is a schematic diagram of the carbon source substitution fermentation results in Example 3 of the present invention;

[0018] Figure 3 This is a schematic diagram of the nitrogen source replacement fermentation results in Example 3 of the present invention;

[0019] Figure 4 Schematic diagram of the effect of pH on strain growth in Example 3 of the present invention;

[0020] Figure 5 Schematic diagram showing the effect of salt type and concentration on bacterial growth in Example 3 of the present invention;

[0021] Figure 6 Schematic diagram of the aerobic nitrification and denitrification capabilities of the strain in Example 4 of the present invention;

[0022] Figure 7 This is a schematic diagram showing the effect of temperature on the denitrification performance of the strain in Example 4 of the present invention;

[0023] Figure 8 Schematic diagram of the anoxic denitrification ability of the strain in Example 4 of the present invention;

[0024] Figure 9 This is a schematic diagram of the bacterial strain particle flocs in Example 5 of the present invention;

[0025] Figure 10 Schematic diagram of the denitrification and COD degradation capabilities of the strain in Example 5 of the present invention.

[0026] The heterotrophic nitrification and denitrification strain provided by the present invention is named Pseudomonas stutzeri YXH-102; its preservation institution is the General Microbiology Center of the China Culture Collection Administration Committee, located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences; the preservation number is: CGMCC No. 27688, and the preservation date is: June 25, 2023. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the embodiments.

[0028] The Pseudomonas stutzeri strain YXH-102 provided herein exhibits morphological characteristics in LB medium: pale yellow colonies with irregular edges and a wrinkled, moist, translucent surface. It is Gram-negative, non-spore-forming, short rod-shaped. Strain YXH-102 is capable of both heterotrophic aerobic nitrification and denitrification, as well as anaerobic denitrification, and has a wide temperature and pH adaptability range.

[0029] Example 1: Rapid separation, purification and enrichment screening of heterotrophic nitrification and denitrification strains

[0030] Water samples and sediments from a similar high-salt environment in Shanxi Salt Lake were selected and enriched, screened, and separated according to the following methods.

[0031] (1) Culture medium formula (g / L)

[0032] Heterotrophic nitrification medium 1a: ammonium chloride 1.0, sodium succinate 8.5, KH2PO4 1.0, MgSO4·7H2O 1.0, CaCl2·6H2O 0.2, FeCl3·6H2O 0.05, sodium molybdate 0.015;

[0033] Heterotrophic nitrification medium 1b: ammonium chloride 3.0, sodium succinate 8.5, KH2PO4 1.5, MgSO4·7H2O 0.8g / L, CaCl2·6H2O 2, FeCl3·6H2O 0.5, sodium molybdate 0.02;

[0034] Heterotrophic nitrification medium 1c: ammonium chloride 2.0, sodium succinate 8.5, KH2PO4 1.2, MgSO4·7H2O 0.5, CaCl2·6H2O 1, FeCl3·6H2O 0.3g / L, sodium molybdate 0.018;

[0035] Adjust the pH of the above culture medium to 7.0 and sterilize at 121°C for 20 minutes. Add 0.1% (v / v) thymol blue (BTB) to the liquid culture medium to create a chromogenic medium. Add 2% agar to the above culture medium to create a solid chromogenic medium. Among the above culture media, heterotrophic nitrification medium 1c is the most optimal.

[0036] Denitrification medium: Replace the ammonium chloride in the heterotrophic nitrification medium with KNO3 to create a denitrification medium. For medium 1a, replace KNO3 with 1g / L; for medium 1b, replace KNO3 with 3g / L; and for medium 1c, replace KNO3 with 2g / L. Of these media, medium 1c achieved the best results.

[0037] LB medium (g / L): peptone 10, yeast powder 5, NaCl 10, add 2% agar to prepare a solid medium.

[0038] For screening of high-salt-tolerant strains, sodium chloride can be added to the above culture medium to 30 g / L to obtain a high-salt culture medium.

[0039] (2) Enrichment and domestication

[0040] Collected water and sediment samples were inoculated at a 3% inoculum into 250 mL of sterilized heterotrophic nitrification medium. The samples were incubated at 30°C and 180 rpm in a shaking incubator. After 48 hours, the culture fluids that showed clear color were tested using nitrite and nitrate rapid detection kits to observe the accumulation of nitrate and nitrite. The culture fluids that showed clear color were selected and inoculated into fresh denitrification chromogenic medium at a 3% inoculum volume. After 48 hours, the culture fluids that showed clear color were selected and inoculated into fresh heterotrophic nitrification chromogenic medium at a 3% inoculum volume. Following these steps, three cycles of acclimatization were repeated. Finally, ammonia nitrogen and nitrate nitrogen were qualitatively or quantitatively determined using a Lianhua Technology rapid detection instrument (reagent). Those that showed clear results were selected for passage and acclimatization or isolation and screening. This method can effectively screen out microorganisms that utilize ammonia nitrogen for growth but do not nitrify.

[0041] (3) Strain screening, isolation and verification

[0042] Take 1mL of the bacterial solution with high ammonia nitrogen removal rate after acclimation and culture, perform gradient dilution, evenly spread on the solid denitrification color culture medium, and culture in a constant temperature incubator at 30℃ for 24 to 48h. Taking advantage of the fact that denitrifying bacteria can turn the color culture medium blue, pick the blue single colony in the solid color culture medium and use LB culture medium for single colony purification and culture. The purified single colony is inoculated into the sterilized liquid heterotrophic nitrification culture medium and denitrification culture medium, and cultured at 30℃ and 180r / min shaking table for 3 days to test its heterotrophic nitrification and denitrification ability, and detect the NO3 - 、NO2 - and NH4 + The strains with the strongest nitrification and denitrification abilities were selected for preservation and their characteristics were studied.

[0043] This example provides a method for rapidly screening heterotrophic nitrifying and denitrifying microorganisms, distinguishing between microorganisms that utilize ammonia nitrogen solely as a nutrient or those that can also use it as a nitrification substrate to provide energy. This method was used to isolate and isolate microorganisms that utilize ammonia nitrogen as a nutrient or as an energy source for nitrification. This method was used to isolate a highly efficient, salt-tolerant, heterotrophic nitrifying and denitrifying strain, designated YXH-102, from over 30 bacterial strains.

[0044] Example 2: Molecular Biological Identification of Strain YXH-102

[0045] The strain YXH-102 was identified by 16S rRNA sequencing and compared with the 16S rRNA sequence database in NCBI. The strain was found to have a homology of 99.93% with Pseudomonas stutzeri and was identified as Pseudomonas stutzeri. The morphological characteristics of strain YXH-102 in LB medium after 24 hours of culture ( Figure 1 ), the colonies are pale yellow with irregular edges and a wrinkled, moist, translucent surface. Gram-negative, non-spore-forming, short rods.

[0046] Example 3: Key factors affecting the growth of strain YXH-102

[0047] 1. Effects of carbon and nitrogen sources on the growth of strain YXH-102

[0048] Carbon source and nitrogen source are essential energy substances in the growth process of microorganisms and are also important elements for the formation of microbial life. The present invention uses starch, sucrose, glucose, sodium citrate, methanol, ethanol and sodium acetate with an addition amount of 2g / L as the sole carbon source to replace the carbon source (sodium succinate 8.5g / L) of the original heterotrophic nitrification medium, inoculates the seed liquid of strain YXH-102, and cultures it in the nitrification medium with shaking. The OD600 of the culture is measured after 24 hours. The results are as follows: Figure 2 The present invention uses ammonium chloride, ammonium nitrate, potassium nitrate, urea, peptone, yeast powder, etc. added at an amount of 2g / L as the sole nitrogen source to replace the ammonium chloride in the original heterotrophic nitrification medium, inoculates the seed liquid of strain YXH-102, and cultures it in the nitrification medium with shaking. The OD600 of the strain is measured for 24 hours. The results are as follows: Figure 3 The results showed that the strain YXH-102 has a broad spectrum of carbon sources and prefers organic nitrogen sources such as peptone yeast powder and inorganic nitrogen sources such as nitrate, which provides a basis for its fermentation and practical application.

[0049] 2. Effect of pH on the growth of strain YXH-102

[0050] pH is an important factor affecting microbial growth, affecting the enzyme activity and membrane permeability of microorganisms, thereby affecting the growth and function of microorganisms. The present invention uses LB culture medium as the basis, adjusts different initial pH, inoculates 3% of the seed solution of strain YXH-102, and cultures with shaking. The OD600 within 48 hours is measured. The results are as follows: Figure 4 The results showed that strain YXH-102 was more suitable for growth under alkaline conditions. Growth was poor at pH 5, with the optimum pH at 7. It grew well within the pH range of 6 to 9, indicating that it has a good pH adaptability range.

[0051] 3. Effects of Salt Type and Concentration on the Growth of Strain YXH-102

[0052] Inorganic salts affect microbial growth rate, metabolic pathways, cell structure, and function by regulating osmotic pressure. Considering the impact of different salt ions on microorganisms, including potential inhibitory effects, this study employed a high-density fermentation medium formulation supplemented with NaCl, Na2SO4, and CaCl2, to investigate the effects of different concentrations on the growth of strain YXH-102. OD values were measured after 24 and 48 hours to evaluate the effects of salt type and concentration on strain culture.

[0053] The results showed that ( Figure 5 ) For strain YXH-102, it has a certain salt tolerance to the above salts (NaCl, Na2SO4, CaCl2), and the adapted concentration is in the range of 1% to 3%. When the salt concentration is greater than 5%, an inhibitory effect begins to appear, especially Na + Ionic salts greater than 10% seriously inhibit the growth of bacteria; among them, Cl - The inhibitory effect is greater than that of SO4 2- , Na + The inhibitory effect was greater than that of Ca 2+ .

[0054] Example 4: Evaluation of the denitrification ability of strain YXH-102

[0055] 1. Aerobic nitrification and denitrification ability test of strain YXH-102

[0056] (1) Preparation of seed solution: YXH-102 was inoculated into LB medium and cultured at 30°C and 180 rpm for 24 h. 3 mL of the culture was taken and centrifuged at 5000 rpm. The supernatant was removed and washed with sterile water and centrifuged twice. Finally, the culture was resuspended in 3 mL of sterile water as the seed solution.

[0057] (2) Inoculation: The resuspended seed solution of YXH-102 prepared in (1) was inoculated into a 250 mL Erlenmeyer flask containing 100 mL of high-salt heterotrophic nitrification medium with ammonium sulfate (100 mg / L) as the sole nitrogen source, and cultured in a shaking incubator at 30°C and a rotation speed of 180 r / min;

[0058] (3) Interval sampling measurement: The degree of ammonia nitrogen removal, nitrate nitrogen and nitrite nitrogen accumulation of the strain were measured at 2h, 6h, 12h, 24h, 30h, 36h, 48h and 60h, and its growth curve was drawn simultaneously.

[0059] like Figure 6As shown in the data, the accumulation of nitrite nitrogen reached its maximum value in 18 hours; the accumulation of nitrate nitrogen reached its maximum value in 24 hours; the bacterial growth reached its maximum value in 30 hours; the removal rates of total nitrogen and ammonia nitrogen reached 95.7% and 97.3% respectively in 36 hours; the removal rates of total nitrogen and ammonia nitrogen reached 97.6% and 99.7% respectively in 48 hours; the above results indicate that strain YXH-102 has heterotrophic nitrification and denitrification functions under aerobic and 3% NaCl conditions, and has a strong denitrification ability.

[0060] 2. Effect of temperature on the denitrification performance of strain YXH-102

[0061] Temperature is an important factor affecting the denitrification activity of denitrifying microorganisms. In the present invention, 100 mL of high-salt heterotrophic nitrification culture medium with ammonium sulfate (100 mg / L) as the sole nitrogen source was used, and the initial pH was 7. The growth effect and denitrification performance of YXH-102 were investigated after culturing for 48 hours at three different temperatures: 10°C, 15°C, 25°C, 30°C, 37°C, 42°C, and 45°C. The total nitrogen (TN) in the supernatant and the OD in the culture medium were determined. 600 The results show that Figure 7 The results showed that the denitrification enzyme activity of strain YXH-102 has a wide temperature adaptation range (15~42℃).

[0062] 3. Detection of the ability of strain YXH-102 to denitrify under anoxic conditions

[0063] (1) Preparation of seed solution: YXH-102 was inoculated into LB medium and cultured at 30°C and 180 rpm for 24 h. 50 mL was taken and centrifuged at 5000 rpm. The supernatant was removed and washed with liquid high-salt denitrification medium and centrifuged twice. Finally, the suspension was resuspended in 50 mL of high-salt denitrification medium as seed solution.

[0064] (2) Inoculation: The resuspended seed solution of YXH-102 prepared in (1) was inoculated into 450 mL of high-salt denitrification medium with potassium nitrate as the sole nitrogen source (nitrate nitrogen adjusted to 100 mg / L) in a 500 mL Shuniu blue-capped bottle, cultured in a 30°C incubator, and shaken every 12 h.

[0065] (3) Interval sampling measurement: The degradation of nitrate nitrogen and accumulation of nitrite nitrogen by strain YXH-102 were measured at 12 h, 24 h, 36 h, 48 h, and 60 h, and its growth curve was drawn simultaneously.

[0066] like Figure 8 As shown, the strain was able to utilize nitrate as a nitrogen source for growth under conditions of anoxic conditions and 3% NaCl, with the bacterial body reaching its maximum value in 24 hours. At the same time, it was also capable of denitrification, with a degradation rate of 98.7% in 36 hours, and only a small amount of nitrite accumulated during the denitrification process.

[0067] Example 5: Fermentation of strain YXH-102 and its application in actual sewage projects

[0068] 1. Preparation of granular flocculant and its application in low-temperature and high-concentration domestic sewage

[0069] Strain YXH-102 was cultured sequentially in LB shake flasks, seed cultures, and fermenters. A single colony was picked from the LB medium and inoculated into liquid LB medium. The culture was incubated in a shaker at 200 rpm and 28°C for 24 hours. A 3% inoculum was transferred to a 100L fermenter containing denitrification medium and incubated at 28°C for 20 hours to obtain a seed culture. A 5% inoculum of the primary seed culture was transferred to a 1-ton fermenter containing denitrification medium and maintained at 28°C. The dissolved oxygen was controlled at 20% to 30% and the fermentation speed was 100 to 150 rpm. The culture was incubated for 18 to 20 hours. When the viable count reached 500 million to 1 billion CFU / mL, the fermentation was terminated and the fermenter was removed from the fermenter. The culture was allowed to settle for approximately 12 hours. The precipitate (approximately 1 / 10 of the fermentation liquid) was then discharged and canned to obtain a concentrated granular flocculant inoculum of strain YXH-102. This method of producing granular bacterial agents is suitable for small sewage treatment plants, purification tanks, integrated sewage treatment equipment, etc., reducing production and transportation costs and facilitating on-site addition and use.

[0070] The seeds and fermentation medium are prepared by the following process:

[0071] Seeds and fermentation medium 5a: KNO3 1.0 g / L, sucrose 10 g / L, KH2PO4 1.0 g / L, MgSO4·7H2O 0.5 g / L, CaCl2·6H2O 0.2 g / L, FeCl3·6H2O 0.05 g / L, sodium molybdate 0.02 g / L;

[0072] Seed and fermentation medium 5b: KNO3 1.0 g / L, sucrose 20 g / L, KH2PO4 1.5 g / L, MgSO4·7H2O1.0 g / L, CaCl2·6H2O 2 g / L, FeCl3·6H2O 0.5 g / L, sodium molybdate 0.015 g / L;

[0073] Seed and fermentation medium 5c: KNO3 1.0 g / L, sucrose 15 g / L, KH2PO4 1.3 g / L, MgSO4·7H2O 0.81.0 g / L, CaCl2·6H2O 1 g / L, FeCl3·6H2O 0.3 g / L, sodium molybdate 0.018 g / L;

[0074] The above culture medium was adjusted to pH 7.0 and 121°C and sterilized for 30 minutes. The seed and fermentation medium 5c culture medium was the best. Under this culture medium condition, the strain YXH-102 could form 1-2 mm particle flocs ( Figure 9 ).

[0075] Preferably, the fermentation broth concentrated granular inoculant is used to treat high-concentration rural domestic wastewater. A buried septic tank in Shandong Province, which had long been substandard in sewage treatment during winter (after November, temperatures between 10°C and 15°C), was selected, particularly for its poor ammonia nitrogen treatment performance. On November 26th, strain YXH-102 concentrated granular flocculant was added at a volume of 1 / 10,000 and inoculated into both the aerobic and anaerobic tanks of the sewage tank.

[0076] The results show that ( Figure 10 The effect of the inoculant was apparent about five days after addition, and the effluent reached Class A discharge standards after 10 days. This also shows that strain YXH-102 has the ability to remove nitrogen at low temperatures (average ammonia nitrogen removal rate of 91.9%) and can also promote the degradation and utilization of COD.

[0077] 2. High-density fermentation agent and its application in high-salt and high-temperature wastewater

[0078] The strain YXH-102 was cultured in LB shake flasks, seed culture, and fermentation tanks in sequence. A single colony was picked from the LB culture medium and inoculated into liquid LB culture medium, cultured in a shaker at 200 rpm and 28°C for 24 hours; 3% of the inoculation was transferred to a 100L fermenter filled with denitrification medium and cultured at 28°C for 24 hours to obtain a first-level seed culture solution. 10% of the inoculation amount of the first-level seed culture solution was transferred to a 1-ton fermenter filled with fermentation medium to obtain a second-level seed culture solution; 10% of the inoculation amount of the second-level seed culture solution was transferred to a 10-ton fermenter filled with fermentation medium. For the first and second fermentations, the temperature was controlled at 28°C, the dissolved oxygen was controlled at 20% to 30%, the rotation speed was 100 rpm to 150 rpm, and the culture was carried out for 24 hours, and the viable bacterial count reached 8.0×10 9 When the CFU / mL is around, the fermentation is terminated and the tank is removed.

[0079] Use a high-density fermentation medium for seeds and fermentation. The medium formula is: 20g / L peptone, 10g / L sucrose, 1.5g / L K2HPO4, 1.5g / L MgSO4·7H2O, pH 7.5; sterilize at 121°C for 30 minutes. Alternatively, 15g / L or 20g / L sucrose can be used. Using 15g / L sucrose provides the best results.

[0080] This fermentation medium, strain YXH-102, produces a large amount of extracellular polysaccharides. Furthermore, depending on the primary salt content of the high-salinity wastewater, appropriate salt can be added (at a concentration of 1 / 2 the actual wastewater salt concentration) to reduce inactivation of the bacterial agent due to osmotic pressure imbalance during the dosing process. This method is suitable for denitrification of specific high-salinity wastewater.

[0081] Preferably, the high-density fermentation agent is applied to the treatment of high-salt wastewater from petrochemical reverse osmosis. The influent indicators of a certain petrochemical reverse osmosis high-salt wastewater are: TDS 82642.2 mg / L; sulfate 20-30 g / L; total nitrogen 120 mg / L; temperature, 37-42°C; the process adopted is aerobic-anaerobic-aerobic. The high sulfate and high temperature characteristics of this wastewater are the difficulties in its treatment process, especially denitrification. The strain YXH-102 high-density fermentation agent is added at a volume of one ten-thousandth and inoculated into the three process sections of "aerobic-anaerobic-aerobic". Other process parameters remain unchanged. After one week of operation, the ammonia nitrogen removal rate reaches 85%, and the total nitrogen removal rate is more than 73%, meeting the petrochemical wastewater discharge standard (total nitrogen ≤ 40 mg / L). It is inferred that if the carbon source input is increased, the removal of total nitrogen can be further promoted. The results showed that strain YXH-102 can effectively carry out nitrification and denitrification in high-sulfate and high-temperature wastewater.

[0082] However, the above description is merely a specific embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the scope of protection of the present invention should still fall within the scope covered by the claims of the present invention.

Claims

1. A heterotrophic nitrification and denitrification strain, characterized in that: The strain was named Pseudomonas stutzeri ( Pseudomonas stutzeri ) YXH-102; the strain is deposited in the General Microbiology Center of China Culture Collection Administration of Microorganisms, with the deposit number being: CGMCC No.27688.

2. The method for cultivating heterotrophic nitrification and denitrification strains according to claim 1, wherein: The strain was cultured using a heterotrophic nitrification medium, wherein the components of the heterotrophic nitrification medium were: 1.0-3.0 g / L ammonium chloride, 8.5 g / L sodium succinate, 1.0-1.5 g / L KH2PO4, 0.5-1.0 g / L MgSO4·7H2O, 0.2-2 g / L CaCl2·6H2O, 0.05-0.5 g / L FeCl3·6H2O, and 0.015-0.02 g / L sodium molybdate.

3. The method for cultivating heterotrophic nitrification and denitrification strains according to claim 1, wherein: The strain is cultured using a heterotrophic denitrification medium, wherein the components of the heterotrophic denitrification medium are: KNO3 1.0-3.0 g / L, sodium succinate 8.5 g / L, KH2PO4 1.0-1.5 g / L, MgSO4·7H2O 0.5-1.0 g / L, CaCl2·6H2O 0.2-2 g / L, FeCl3·6H2O 0.05-0.5 g / L, and sodium molybdate 0.015-0.02 g / L.

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