Delftia strain and use thereof

Abstract

The application belongs to the field of industrial microorganisms, and particularly discloses a Delftia sp. strain and application thereof. The Delftia sp. Y19 strain of the application is preserved in the China General Microbiological Culture Collection Center, and has a preservation number of CGMCC No. 26000. The Delftia sp. Y19 strain of the application is a heterotrophic nitrifying and aerobic denitrifying bacterium capable of efficiently denitrifying in a low carbon-nitrogen ratio water body with mixed nitrogen sources of nitrate nitrogen and ammonia nitrogen.

Description

Technical Field

[0001] This invention relates to the field of industrial microbiology, and in particular to a Delftobacterium strain with aerobic denitrification capabilities and a method for treating wastewater under low carbon-to-nitrogen ratio conditions. Background Technology

[0002] While my country's urban sewage and industrial wastewater treatment efficiency is relatively high, decentralized point source pollution from rural sewage and non-point source pollution from farmland runoff from rainfall or irrigation remain serious problems. In some areas, water pollution caused by nitrogen-containing compounds such as nitrates, nitrites, and ammonium salts remains severe.

[0003] When the nitrogen content in water is too high, it not only damages the ecological environment but also has adverse effects on human health. The main harms caused by nitrogen pollution are as follows: (1) Eutrophication of water bodies. The discharge of large amounts of nitrogen-containing substances into water bodies causes the rapid proliferation of floating plants, forming algal blooms or even red tides that cover the water surface, resulting in a decrease in the oxygen concentration in the water body. Fish and other organisms die in large numbers due to lack of oxygen, ultimately leading to foul-smelling and blackened water, which also seriously affects the ornamental value of the water body. (2) Harm to aquatic organisms and affect human health. When the NH4+ content in the water body is high, it can cause eutrophication of water bodies. + When the nitrite concentration is greater than 3 mg / L, most fish die within 24-96 hours. Nitrite readily binds to hemoglobin in the blood, which carries oxygen, thus increasing the iron content. 2+ Oxidized into Fe 3+ Oxygen transport is restricted, leading to hypoxia in human tissues and causing methemoglobinemia, which has a serious impact on infants under 3 months old, and in severe cases, can cause suffocation and death. (3) Increased cost of wastewater treatment. When physical and chemical methods are used to treat nitrogen pollution in water bodies, the increase in nitrogen content in wastewater will inevitably lead to an increase in the amount of adsorbents and reagents used. In addition, when the ammonia nitrogen content in the water body increases, the copper-containing parts in the wastewater treatment equipment will react with the ammonia nitrogen, causing equipment wear and tear, and thus shortening the service life of the equipment.

[0004] Biological methods are currently the most common way to remove nitrogen from water bodies. Traditional biological methods for wastewater denitrification require two separate processes: autotrophic aerobic nitrification and heterotrophic anoxic denitrification. Nitrification and denitrification have diametrically opposed requirements for organic substrates and oxygen. Therefore, traditional biological denitrification must be carried out separately, increasing investment costs. Furthermore, nitrifying bacteria grow slowly, have low biomass concentrations, and are weakly resistant to shock loads.

[0005] The emergence of heterotrophic nitrifying aerobic denitrifying bacteria has disrupted traditional nitrogen removal theories, enabling single strains to effectively remove organic matter from wastewater while simultaneously performing nitrification and denitrification. This allows for simultaneous nitrification and denitrification in the same aeration tank, potentially saving investment and reducing operational complexity. Furthermore, these microorganisms exhibit strong environmental tolerance, overcoming the shortcomings of traditional biological nitrogen removal methods. Currently, many heterotrophic nitrifying aerobic denitrifying strains have been isolated and screened, such as *Acinetobacter calcoaceticus*, *Bacillus megatherium*, *Klebsiella oxytoca*, *Halomonas sp. GJWA3*, and *Pseudomonas aeruginosa*. Compared to autotrophic nitrifying and anaerobic denitrifying bacteria, heterotrophic nitrifying aerobic denitrifying bacteria offer advantages such as rapid growth, high organic loading capacity, and strong environmental adaptability, making them promising candidates for wastewater treatment. Summary of the Invention

[0006] One object of this invention is to provide a Delftia sp. Y19 strain, which is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 26000. It is a heterotrophic nitrifying aerobic denitrifying bacterium capable of efficiently removing nitrogen from water bodies with mixed nitrate and ammonia nitrogen sources and low carbon-to-nitrogen ratios.

[0007] Another object of the present invention is to provide the use of Delftia sp. Y19 strain in the denitrification treatment of wastewater with a low carbon-to-nitrogen ratio.

[0008] Another object of the present invention is to provide a method for denitrification treatment of wastewater with a low carbon-to-nitrogen ratio.

[0009] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0010] According to one aspect, the present invention provides a Delftia sp. Y19 strain, which is deposited at the China General Microbiological Culture Collection Center, with accession number CGMCC No. 26000.

[0011] In this invention, the Delftia sp. Y19 strain was deposited on October 31, 2022, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 26000, taxonomically named Delftia sp., and the address of the depository is No. 3, No. 1, Beichen West Road, Chaoyang District, Beijing.

[0012] In this invention, the Delftia sp. Y19 strain was isolated and screened from urban river water bodies, and it has the following biological characteristics:

[0013] Colony characteristics: raised in the middle, with neat edges, smooth surface, yellowish-brown and opaque;

[0014] Cell morphology characteristics: regular rod-shaped, cell size (1.1~1.9)μm×(0.5~0.7)μm, surface wrinkled, no flagella.

[0015] Biochemical characteristics:

[0016] This bacterium can grow in a mixed nitrogen source of ammonium salts and nitrates;

[0017] This bacterium can grow in yeast extract peptone;

[0018] This bacterium can grow under neutral or slightly alkaline conditions (pH 7–9);

[0019] This bacterium can grow in dissolved oxygen concentrations of 5.38–6.35 mg / L.

[0020] According to another aspect, the present invention provides the use of Delftia sp. Y19 strain in the denitrification treatment of wastewater with a low carbon-to-nitrogen ratio, wherein the wastewater contains ammonia nitrogen (NH4+). + The concentration of nitrate nitrogen (NO3-N) was 20±1.5 mg / L. - The concentration of nitrogen (N) was 20±1.5 mg / L, the carbon-nitrogen ratio was 10±1, and the COD concentration was 400±10 mg / L.

[0021] In another aspect, the present invention provides a method for denitrification treatment of wastewater with a low carbon-to-nitrogen ratio, comprising the steps of nitrification and denitrification using the Delftia sp. Y19 strain of the present invention, wherein ammonia nitrogen (NH4) in the wastewater is reduced. + The concentration of nitrate nitrogen (NO3-N) was 20±1.5 mg / L. - The concentration of nitrogen (N) was 20±1.5 mg / L, the carbon-nitrogen ratio was 10±1, and the COD concentration was 400±10 mg / L.

[0022] The Delftia sp. Y19 strain of this invention is capable of heterotrophic nitrification and aerobic denitrification. Heterotrophic nitrification is the process by which heterotrophic microorganisms oxidize ammonia / ammonium to hydroxylamine, nitrite, and nitrate under aerobic conditions. Aerobic denitrification involves the bacteria using both oxygen and nitrate as electron acceptors, thereby reducing nitrogenous compounds in wastewater and achieving denitrification. It exhibits denitrification characteristics under a C / N ratio of 10 and aerobic conditions. Inoculating it into a simulated natural aquatic environment allows for simultaneous nitrification and denitrification of nitrogenous wastewater.

[0023] In one embodiment, the method for denitrification treatment of low carbon-to-nitrogen ratio wastewater of the present invention includes the following steps:

[0024] S1, the Delftia sp. Y19 strain of the present invention is inoculated into LB liquid medium for activation;

[0025] S2 involves inoculating the bacterial solution obtained in S1 into wastewater or simulated wastewater for cultivation to remove the nitrogen source.

[0026] In S1, preferably, Delftia sp. Y19 strain is picked up with an inoculation loop and added to 100 mL of LB liquid medium for activation.

[0027] In S1, preferably, activation is performed by incubation at 30°C with shaking at 120 rpm for 12–36 hours, until OD... 600 It is 1.5.

[0028] In S1, preferably, the LB liquid culture medium is: 10 g / L peptone, 5 g / L yeast extract, 10 g / L NaCl, and distilled water to a final volume of 100 mL, with a pH of 7.

[0029] In S2, preferably, the inoculum size is 1%, and the culture is carried out at 30°C and 120 r / min for 2 days with shaking.

[0030] In S2, preferably, the concentrations of ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, total nitrogen, and COD in the wastewater or simulated wastewater are measured at different times (e.g., 0h and 48h).

[0031] The Delftia sp. Y19 strain of the present invention exhibits excellent heterotrophic nitrification and aerobic denitrification performance in water bodies with low carbon-to-nitrogen ratio (C / N = 10) and mixed nitrogen sources (ammonium salts and nitrates). Attached Figure Description

[0032] Figure 1 The results show the screening results for heterotrophic nitrifying aerobic denitrifying bacteria.

[0033] Figure 2 The denitrification capacity of different strains.

[0034] Figure 3 The denitrification capacity of different strains under low C / N conditions.

[0035] Figure 4 This is a colony diagram of Delftia sp. Y19 strain after bacterial purification and streaking on a plate.

[0036] Figure 5 This is a scanning electron microscope image of Delftia sp. Y19 strain.

[0037] Figure 6 The growth curve of Delftia sp. Y19 strain in LB liquid medium.

[0038] Figure 7 Phylogenetic tree diagram of Delftia sp. Y19 strain.

[0039] Figure 8 The effect of different pH values ​​on the denitrification performance of Delftia sp. Y19 strain.

[0040] Figure 9 The effect of different temperatures on the denitrification performance of Delftia sp. Y19 strain.

[0041] Figure 10 The effect of different rotation speeds on the denitrification performance of Delftia sp. Y19 strain.

[0042] Figure 11 A simulation device for the application of Delftia sp. Y19 strain in denitrification of simulated natural water bodies.

[0043] Figure 12 Application of Delftia sp. Y19 strain in denitrification of simulated natural water bodies. Detailed Implementation

[0044] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0046] The methods for determining ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, and COD involved in the following examples are as follows:

[0047] Ammonia nitrogen was determined using the Nessler's reagent spectrophotometric method for the determination of ammonia nitrogen in water quality (HJ535-2009).

[0048] Nitrite nitrogen (NO2) - -N) was determined using the diazo-coupled spectrophotometric method for the determination of nitrite nitrogen in water quality (GB7493-87);

[0049] Nitrate nitrogen (NO3) - -N) The method for determining nitrate nitrogen in water quality using ultraviolet spectrophotometry (HZ-HJ-SZ-0138) utilizes the absorption of nitrate ions at a wavelength of 220 nm for quantitative determination;

[0050] COD was determined using the rapid digestion spectrophotometric method (GB11914-89).

[0051] The culture medium formulations used in the following examples are as follows:

[0052] Add the components listed in Table 1 to a 1L container and bring the volume to 1000mL with sterile water.

[0053] Table 1 Culture medium formulation

[0054]

[0055]

[0056] Notes: Vickers salt solutions: 6.5 g / L KH₂PO₄·3H₂O, 2.5 g / L MgSO₄·7H₂O, 2.5 g / L NaCl, 0.05 g / L FeSO₄·7H₂O, 0.04 g / L MnSO₄·7H₂O; bromothymol blue solution is obtained by dissolving 1 g of bromothymol blue solution in 100 mL of ethanol; trace element solutions: 4 g / L CuSO₄·5H₂O, 0.7 g / L FeSO₄·7H₂O, 7 g / L FeCl₃·7H₂O, 0.2 g / L CoCl₃·6H₂O, 3.4 g / L NaMoO₄·2H₂O, 2 g / L CaCl₂·2H₂O.

[0057] All culture media were sterilized by autoclaving (121℃, 20 min) during the operation; all operations were performed in a laminar flow hood next to an alcohol lamp.

[0058] The simulated wastewater in the examples utilizes pure water, NH4Cl, KNO3, and C6H. 12O6 and other ingredients were used to simulate low C / N wastewater, which mainly contained 20 mg / L NH4+-N, 20 mg / L NO3--N and 400 mg / L COD.

[0059] Example 1: Screening and Isolation of Heterotrophic Nitrifying-Aerobic Denitrifying Strains

[0060] Enrichment of various bacterial strains in river water: River water from Yuexi River (E: 105°; N: 30°) in Anyue County, Ziyang City, Sichuan Province was collected. 5 mL of fresh river water was added to 100 mL of sterile LB liquid medium and mixed well. The mixture was then placed in a constant temperature shaker at 30°C and 120 r / min for 48 h to enrich the bacterial suspension. 5 mL of the bacterial suspension was then inoculated into fresh LB liquid medium. This enrichment process was repeated three times to obtain a bacterial suspension rich in colonies.

[0061] Screening of heterotrophic nitrifying strains: Add 5 mL of the enriched bacterial suspension to 100 mL of heterotrophic nitrification medium, mix well, and incubate at 30℃ and 120 rpm for 48 h. Observe whether the medium becomes turbid. If it is turbid, inoculate 5 mL of the cultured heterotrophic nitrification medium into 100 mL of fresh heterotrophic nitrification medium and incubate at 30℃ and 120 rpm for 48 h. Repeat this screening process three times. If the medium remains clear, repeat the enrichment and screening steps above.

[0062] Isolation of heterotrophic nitrifying strains: 1 mL of bacterial suspension was serially diluted with sterile water (10, ... 2 10 3 10 4 10 5 After diluting the culture medium by 10⁶, 10⁷ times, sterilize the heterotrophic nitrification solid medium at 121°C for 20 minutes. While still hot, pour the culture medium into sterile plates. After solidification, use a pipette to sequentially transfer 100 μL of the diluted heterotrophic nitrification medium bacterial suspension into the heterotrophic nitrification solid medium. Quickly spread the bacterial suspension evenly onto the petri dishes using a spreading stick. Seal each petri dish with sealing film and invert it in a 30°C constant temperature incubator for 48 hours.

[0063] Purification of heterotrophic nitrifying strains: Based on colony morphology, select colonies with good growth and fast growth rate. Use an inoculation loop to pick up a single colony of the selected bacteria and streak it onto LB solid medium. After streaking, seal the petri dish with sealing film and incubate at 30℃ until complete colonies are visible to the naked eye, thus obtaining the purified strain. Inoculate the purified strain into 100 mL of LB liquid medium and incubate at 30℃ and 120 rpm for 24 h to obtain a bacterial suspension.

[0064] Screening of heterotrophic nitrifying aerobic denitrifying strains: Take 5 mL of the bacterial suspension obtained in the above steps and inoculate it into 100 mL of aerobic denitrification liquid medium. Incubate in a constant temperature shaker at 30℃ and 120 r / min for 48 h. Then take 5 mL of the cultured aerobic denitrification medium and inoculate it into 100 mL of fresh aerobic denitrification liquid medium. Incubate in a constant temperature shaker at 30℃ and 120 r / min for 48 h. Repeat this screening process three times.

[0065] Identification of heterotrophic nitrifying aerobic denitrifying strains: A bacterial suspension was inoculated onto bromothymol blue agar and streaked. The petri dish was then sealed with sealing film and incubated at 30°C until complete colonies were visible to the naked eye. The strain's denitrification ability was indicated by the bromothymol blue agar turning blue. Seven strains that caused the bromothymol blue agar to turn blue were selected: Y4, Y5, Y6, Y8, Y9, Y19, and Y20. Figure 1 As shown.

[0066] Take 2 mL of bacterial suspension from each of the above 7 strains and culture them until the logarithmic OD phase. 600 A bacterial suspension of strain 1.5 was transferred to 100 mL of a secondary screening liquid medium containing sufficient carbon source and incubated at 30 °C and 120 rpm for 72 h. The final NH4 content in the medium was then measured. + -N, NO2 - -N, NO3 - -N, TN (total nitrogen), and COD concentrations, such as Figure 2 As shown. After 48 hours of cultivation, these 7 bacterial strains showed resistance to NH4+ in the culture medium. + -N, NO3 - The removal effects on -N, TN and COD are all good, and the removal effect on NH4 is also good. + The removal rate of -N was generally above 90%, with strains Y8 and Y20 showing particularly good removal rates of NH4+. + The removal rates of -N were 98.7% and 98.4%, respectively; Y8 and Y19 removed NO3. - The removal rates of nitrogen (N) were 89.6% and 85.3%, respectively; in terms of COD removal, Y5 and Y8 achieved COD removal rates of 78.3% and 83.4%, respectively. Based on the screening of microorganisms' ability to remove nitrogen and carbon in water bodies with sufficient organic matter, Y5, Y8, Y19, and Y20 were identified as strains with relatively good capabilities.

[0067] The selected strains Y5, Y8, Y19, and Y20, which exhibited the best denitrification capabilities, were cultured in LB medium until the logarithmic growth phase. 2 mL of the bacterial suspension was then added to 100 mL of simulated wastewater with a low C / N ratio. After reacting for 72 h, NH4 content was measured. + -N, NO2 - -N, NO3 --N, TN, and COD concentrations. Strains exhibiting good denitrification efficiency under low C / N conditions are screened; these strains are the target strains. For example... Figure 3 As shown, strain Y5 is effective against NO3. - -N, NH4 + The removal rates of NO2- and COD were 71.6%, 62.9%, and 70.4%, respectively, while after 48 hours of cultivation, NO2- - The concentration of -N was 18 mg / L, indicating that the system contained NH4+. + -N, NO3 - -N was mostly converted into NO2 by strain Y5 under low C / N conditions. - -N, no nitrogen was removed from the wastewater. Y19 exhibited better denitrification ability under low C / N conditions, particularly for NH4+. + -N, NO3 - The removal rates of NO2, TN, and COD were 51%, 94%, 56%, and 71%, respectively. A small amount of NO2 was present at the end of the experiment. - -N accumulation may be related to the denitrification pathway of HN-AD strains, NH4+. + -N, NO3 - -N is first oxidized and reduced to NO2. - -N, based on analysis, Y19 can be used as the experimental strain for further related research.

[0068] The characteristics of the screened strain Y19 on solid culture medium: raised in the middle, with neat edges, smooth surface, yellowish-brown and opaque. Figure 4 As shown; its morphological characteristics are regular rod-shaped, with a size of (1.1~1.9)μm×(0.5~0.7)μm, such as... Figure 5 As shown.

[0069] Nitrogen removal capacity assay of heterotrophic nitrifying aerobic denitrifying strains: The target strain obtained from one inoculation loop was cultured in 100 mL of LB liquid medium at 30℃ and 120 rpm for 24 h to obtain a bacterial suspension. 2 mL of the bacterial suspension was transferred to 100 mL of double-screening liquid medium and cultured at 30℃ and 120 rpm for 72 h. The final NH4+ ion concentration in the medium was then measured. + NO2 - NO3 - and COD concentration.

[0070] Growth curve determination of heterotrophic nitrifying aerobic denitrifying strains: One inoculation loop of the target strain was added to 100 mL of LB liquid medium and cultured at 30℃ with constant temperature shaking at 120 rpm for 36 h. Samples were taken at 1, 2, 4, 6, 8, 12, 24, 32, and 36 h, and absorbance was measured at 600 nm using a UV spectrophotometer. A growth curve was plotted based on the absorbance. Figure 6 It can be seen that the Delftia sp. Y19 strain grows and metabolizes rapidly, reaching its fastest growth phase at 12 hours. 600 =1.5, reaching a stable period after 24 hours.

[0071] Example 2: PCR amplification and sequencing of the 16S rDNA gene of Delftia sp. Y19 strain

[0072] ① DNA extraction from the strain: The strain obtained in the above steps was subjected to bacterial genomic DNA extraction using a kit (Tsingke);

[0073] ② PCR analysis of the strain: The full-length 16S rRNA gene sequence of the strain's genomic DNA obtained in step ① was sequenced and amplified by PCR using universal primers.

[0074] The universal primers used are: 27F: 5'-GAGAGTTTGATCCTGGCTCAG-3' (SEQ ID NO.2); 1492R: 5'-TACGGCTACCTTGTTACGAC-3' (SEQ ID NO.3);

[0075] Amplification conditions: 1 μl DNA template, 45 μl 1×TSE101 Gold Mix, 2 μl each of upstream and downstream universal primers;

[0076] After mixing, place it in a PCR instrument for amplification. The PCR program is as follows: 98℃ pre-denaturation for 3 min; 98℃ denaturation for 10 s, 55℃ annealing for 15 s, 72℃ extension for 5 min, 39 cycles.

[0077] After PCR, agarose gel electrophoresis (2 μl sample + 6 μl bromophenol blue) was performed at 300V for 12 minutes to detect whether the PCR amplification was successful.

[0078] When electrophoresis yields a 1500bp fragment, PCR amplification is considered successful; conversely, when electrophoresis does not yield the relevant fragment, PCR amplification is considered a failure.

[0079] ③ DNA sequencing of the strain: The strain was sequenced using universal primers (27F / 1492R) at Qingke Biotechnology Co., Ltd., and its nucleotide sequence is shown in SEQ ID NO.1. The sequence length is 1537 bp.

[0080] The selected strains were sequenced using 16S rRNA and compared with data in NCBI. The results showed that the isolated bacteria belonged to *Delftia sp.*. Figure 7 As shown. This bacterium was deposited at the China General Microbiological Culture Collection Center (CGMCC) on October 31, 2022, with accession number CGMCC No. 26000.

[0081] Example 3: Analysis of Factors Affecting the Denitrification Performance of Delftia sp. Y19 Strain

[0082] 1. Effect of pH on the denitrification performance of Delftia sp. Y19 strain

[0083] The initial concentrations of ammonia nitrogen and nitrate nitrogen were set at 20 mg / L, C / N = 10, and pH values ​​were set to 5, 7, and 9, respectively. One loopful of the target bacterial strain was inoculated into 100 mL of LB liquid medium and cultured at 30°C and 120 rpm for 24 h to obtain an activated bacterial suspension. This suspension was then inoculated into 300 mL of simulated wastewater at a 1% inoculation rate and cultured at 30°C and 120 rpm for 48 h. The results are as follows. Figure 8 As shown.

[0084] The results showed that the Delftia sp. Y19 strain exhibited good pH adaptability, with removal rates of approximately 84.7% and 69.1% for nitrate nitrogen and ammonia nitrogen, respectively, at pH 9. At pH 7, the Delftia sp. Y19 strain showed generally good removal efficiency for nitrate nitrogen and ammonia nitrogen, with removal rates of 86.8% and 70.4%, respectively.

[0085] 2. Effect of temperature on the denitrification performance of Delftia sp. Y19 strain

[0086] The initial concentrations of ammonia nitrogen and nitrate nitrogen were set at 20 mg / L, C / N = 10, and the temperatures were set at 15, 20, 30, and 40℃. One loopful of the target bacterial strain was inoculated into 100 mL of LB liquid medium and cultured at 30℃ with constant temperature shaking at 120 rpm for 24 h to obtain an activated bacterial suspension. This suspension was then inoculated into 300 mL of simulated water at a 1% inoculation rate and cultured for 48 h. The results are as follows... Figure 9 As shown.

[0087] The results showed that the removal rates of nitrate nitrogen and ammonia nitrogen by the Delftia sp. Y19 strain were 93.9% and 78.8%, respectively, at a temperature of 30℃.

[0088] 3. Effect of rotational speed on the denitrification performance of Delftia sp. Y19 strain

[0089] The initial concentrations of ammonia nitrogen and nitrate nitrogen were set at 20 mg / L, with a C / N ratio of 10. Rotation speeds were set at 60, 120, and 200 r / min. One loopful of the target bacterial strain was inoculated into 100 mL of LB liquid medium and cultured at 30°C and 120 r / min for 24 h to obtain an activated bacterial suspension. This suspension was then inoculated into 300 mL of simulated water at a 1% inoculation rate and cultured for 48 h. The results are as follows... Figure 10 As shown.

[0090] The results showed that the removal rates of nitrate nitrogen and ammonia nitrogen by the Delftia sp. Y19 strain were 78.7% and 72.6%, respectively, at a rotation speed of 120 r / min.

[0091] Example 4: Application of Delftia sp. Y19 strain in simulated natural water bodies

[0092] The denitrification effect of Delftiasp. Y19, screened from the bottom sediment of Yanhu Lake (E:104°, N:30°) at Chengdu University of Technology in Chengdu, was investigated.

[0093] In the device (such as Figure 11 The bottom was covered with 0.1m of bottom sediment. Activated Delftia sp. Y19 strain was added to 350mL of simulated wastewater at a volume ratio of 3%. The ammonia nitrogen (NH4+) in the wastewater was... + -N), nitrate nitrogen (NO3) - The concentrations of NH4+ and COD were 20 mg / L, 20 mg / L, and 400 mg / L, respectively, with a C / N ratio of approximately 10. After cultivation at 15–25℃, the NH4+ concentration in the water was... + -N, NO3 - -N, NO2 - -N and COD concentrations were monitored for 10 consecutive days, and the results are as follows: Figure 12 As shown.

[0094] Depend on Figure 12 It can be seen that the Delftia sp. Y19 strain added in this embodiment has an effect on NO3 in simulated natural water bodies. --N removal was effective, with a removal rate of 100% around day 8, and no NO2 was found in the system by day 10. - The accumulation of -N resulted in a COD removal rate of 100%. The results indicate that the Delftia sp. Y19 strain exhibits strong denitrification and nitrogen removal activity in simulated natural water bodies.

[0095] SEQ ID NO.1

[0096] GTCGAACGGTAACAGGTCTTCGGACGCTGACGAGTGGCGAACGGGTGAGTAATAC

[0097] ATCGGAACGTGCCCAGTCGTGGGGGATAACTACTCGAAAGAGTAGCTAATACCGCA

[0098] TACGATCTGAGGATGAAAGCGGGGGACCTTCGGGCCTCGCGCGATTGGAGCGGCC

[0099] GATGGCAGATTAGGTAGTTGGTGGGATAAAAGCTTACCAAGCCGACGATCTGTAGC

[0100] TGGTCTGAGAGGACGACCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTA

[0101] CGGGAGGCAGCAGTGGGGAATTTTGGACAATGGGCGAAAGCCTGATCCAGCAATG

[0102] CCGCGTGCAGGATGAAGGCCTTCGGGTTGTAAACTGCTTTTGTACGGAACGAAAA

[0103] AGCTCCTTCTAATACAGGGGGCCCATGACGGTACCGTAAGAATAAGCACCGGCTAA

[0104] CTACGTGCCAGCAGCCGCGGTAATACGTAGGGTGCGAGCGTTAATCGGAATTACTG

[0105] GGCGTAAAGCGTGCGCAGGCGGTTATGTAAGACAGATGTGAAATCCCCGGGCTCA

[0106] ACCTGGGAACTGCATTTGTGACTGCATGGCTAGAGTACGGTAGAGGGGGATGGAA

[0107] TTCCGCGTGTAGCAGTGAAATGCGTAGATATGCGGAGGAACACCGATGGCGAAGG

[0108] CAATCCCCTGGACCTGTACTGACGCTCATGCACGAAAGCGTGGGGAGCAAACAGG

[0109] ATTAGATACCCTGGTAGTCCACGCCCTAAACGATGTCAACTGGTTGTTGGGAATTA

[0110] GTTTTCTCAGTAACGAAGCTAACGCGTGAAGTTGACCGCCTGGGGAGTACGGCCG

[0111] CAAGGTTGAAACTCAAAGGAATTGACGGGGACCCGCACAAGCGGTGGATGATGT

[0112] GGTTTAATTCGATGCAACGCGAAAAACCTTACCCACCTTTGACATGGCAGGAAGTT

[0113] TCCAGAGATGGATTCGTGCTCGAAAGAGAACCTGCACACAGGTGCTGCATGGCTG

[0114] TCGTCAGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTT

[0115] GTCATTAGTTGCTACATTCAGTTGAGCACTCTAATGAGACTGCCGGTGACAAACCG

[0116] GAGGAAGGTGGGGATGACGTCAAGTCCTCATGGCCCTTATAGGTGGGGCTACACA

[0117] CGTCATACAATGGCTGGTACAGAGGGTTGCCAACCCGCGAGGGGGAGCTAATCCC

[0118] ATAAAACCAGTCGTAGTCCGGATCGCAGTCTGCAACTCGACTGCGTGAAGTCGGA

[0119] ATCGCTAGTAATCGCGGATCAGCATGCCGCGGTGAATACGTTCCCGGGTCTTGTAC

[0120] ACACCGCCCGTCACACCATGGAGCGGGTCTCGCCAGAAGTAGGTAGCCTAACCG

[0121] CAKE.

Claims

1. A Delftia sp. Y19 strain, which was deposited at the China General Microbiological Culture Collection Center on October 31, 2022, with accession number CGMCC No. 26000.

2. The use of the Delfordia Y19 strain as described in claim 1 in the denitrification treatment of wastewater with a low carbon-to-nitrogen ratio, wherein the concentration of ammonia nitrogen in the wastewater is 20±1.5 mg / L, the concentration of nitrate nitrogen is 20±1.5 mg / L, the carbon-to-nitrogen ratio is 10±1, and the COD concentration is 400±10 mg / L.

3. A method for denitrifying wastewater with a low carbon-to-nitrogen ratio, comprising the steps of nitrification and denitrification using the Delfordia Y19 strain as described in claim 1, wherein the concentration of ammonia nitrogen in the wastewater is 20±1.5 mg / L, the concentration of nitrate nitrogen is 20±1.5 mg / L, the carbon-to-nitrogen ratio is 10±1, and the COD concentration is 400±10 mg / L.

4. The method as described in claim 3, characterized in that, Includes the following steps: S1, the Delfordia Y19 strain is inoculated into LB liquid medium for activation; S2 involves inoculating the bacterial solution obtained in S1 into wastewater or simulated wastewater for cultivation to remove the nitrogen source.

5. The method as described in claim 4, characterized in that, In S1, activation is performed by incubation at 30°C with shaking at 120 rpm for 12–36 hours until OD is reached. 600 It is 1.

5.

6. The method as described in claim 4, characterized in that, In S1, the LB liquid medium consisted of: 10 g / L peptone, 5 g / L yeast extract, 10 g / L NaCl, and distilled water to a final volume of 100 mL, with a pH of 7.

7. The method as described in claim 4, characterized in that, In S2, the concentrations of ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, total nitrogen, and COD in wastewater or simulated wastewater were measured at different times.

Images