LU505228B1 - Application of an efficient aerobic denitrifying actinomycete strain in the treatment of micropolluted water - Google Patents

Abstract

The present invention discloses the application of an efficient aerobic denitrifying actinomycete strain in the field of microbial technology in the treatment of micropolluted water. The actinomycete strain is Streptomyces phaeofaciens LST24, and the effective sequence length of the 16SrRNA of Streptomyces phaeofaciens LST24 is 1412 bp as shown in the sequence listing. The present invention realizes the application of the aerobic denitrifying actinomycete strain LST24 in the treatment of micro-polluted waters, which has efficient nitrogen and carbon removal properties. The aerobic denitrifying actinomycete strain LST24 can effectively reduce the contents of ammonia nitrogen, nitrate, nitrite and COD Mn in micro-polluted waters, and has great application potential in the in-situ treatment of other micro-polluted waters such as landscape water bodies and water source reservoirs. The Streptomyces phaeofaciens strain LST24 is obtained from the overlying water of the landscape water by enrichment, cultivation, separation and purification. The Streptomyces phaeofaciens strain LST24 is grown with nitrate as the sole nitrogen source.

Description

DESCRIPTION

APPLICATION OF AN EFFICIENT AEROBIC

DENITRIFYING ACTINOMYCETES STRAIN IN

TREATMENT OF MICRO-POLLUTED WATER

Technical part

The present invention relates to the field of microbial technology, in particular to the application of an efficient aerobic denitrifying actinomycete strain in the

Treatment of micro-polluted water.

Background technology

With the development of industry and agriculture, urban and rural

Surface waters are exposed to varying degrees of nitrogen pollution. Nitrate in the

Aquatic environment leads to eutrophication of water bodies, which leads to a decrease in

water quality, which poses potential risks to human health and ecosystem stability. In natural aquatic ecosystems, water bodies typically exhibit a slightly polluted state, where the concentration of pollutants (nitrate, organic matter, etc.) is usually below 10 mg/L. The use of physical and chemical methods to remove these pollutants from slightly polluted water is often not cost-effective. Therefore, it is of great importance to develop an efficient and economical

method for cleaning micro-polluted waters. The traditional microbial

Denitrification technology currently involves two reactions: aerobic nitrification and anaerobic denitrification. The presence of dissolved oxygen is an important

Inhibiting factor in the traditional denitrification process. Aerobic denitrification with its strong resistance to dissolved oxygen can = nitrification and

denitrification processes in a bioreactor and has become a hot topic in nitrogen removal research due to its advantages such as affordable price, high efficiency and clean byproducts. Actinomyces are environmentally friendly

Microorganisms with the ability to degrade complex pollutants. They can reproduce not only through asexual spores, but also through mycelium rupture, with strong

Adaptability to different environmental stresses. By isolating an aerobic denitrifying actinomycete strain with good denitrification performance, its

Growth, denitrification and decarbonization properties as well as its application in denitrification and decarbonization in micropolluted waters have been extensively investigated.

This provides new insights for the development of diverse and efficient aerobic

Denitrification biological resources and has important theoretical value and 905228 practical significance for improving denitrification treatment efficiency and

Economic efficiency of micro-polluted waters.

On this basis, the present invention designs an application of an efficient aerobic denitrifying actinomycetes strain in the treatment of micropolluted water to solve the above problems.

Content of the invention

To solve the above problems, the present invention offers the following technical solution:

The application of an efficient aerobic denitrifying actinomycete strain in the

Treatment of slightly polluted water. The actinomycete strain is Streptomyces phaeofaciens LST24, and the effective sequence length of the 16SrRNA of the actinomycete strain

LST24 is 1412 bp, as shown in the sequence listing.

Preferably, Streptomyces phaeofaciens strain LST24 is obtained by enrichment,

Cultivation, separation and purification from the overlying water of

preserved landscape waters.

Preferably, Streptomyces phaeofaciens strain LST24 is used with nitrate as the only

Nitrogen source grown.

Preferably, the Streptomyces phaeofaciens strain LST24 is suitable for nitrogen and

Carbon removal in lightly polluted waters.

Preferably, the micropolluted water body refers to a water body with a

Concentration of pollutants below 10mg/L (such as COD Mn, ammonia nitrogen,

Nitrate nitrogen and nitrite nitrogen).

Preferably, the Streptomyces phaeofaciens strain LST24 from the overlying

Water sample of landscape water body enriched and cultivated on Gaoshi No.l

Medium separated, screened for aerobic denitrification and screened for aerobic

Denitrification fluid inoculated for aerobic continuous cultivation.

Preferably, the aerobic continuous culture uses soluble starch as a carbon source at a temperature of 30 °C; the inoculation amount of Streptomyces phaeofaciens LST24 is 1% of the volume of the aerobic denitrification liquid culture medium.

The application of an efficient aerobic denitrifying actinomycete strain in the

Treatment of slightly contaminated water involves the following specific steps:

S1. Collection and performance testing of strains; LUS05228

Enrichment: on polycarbonate membrane (0.22) uw m) Filter 100 ml

Landscape water sample and immediately place the polycarbonate membrane on solid Gaoshi No.1

Medium with 80 ppm K2Cr207. The medium was incubated for seven days at 30 + 2°C.

All samples were incubated in triplicate (n=3).

Among them, actinomycetes can penetrate the pores of polycarbonate membranes and grow on solid culture medium, while the addition of K2Cr207 increases the competitive

can inhibit the growth of bacteria and fungi on solid culture medium;

The formula of Gaoshi No.1 solid culture medium is: 0.5g/L KNO3, 0.01g/L NaCl, 0.01g/L

FeSO4, 0.5g/L KH2PO4, 0.5g/L MgSO4, 20g/L agar powder, 20g/L soluble starch, and the pH is adjusted to 7.2-7.4;

Preliminary screening: Take enriched and cultured Gao solid culture medium No.1, select dry actinomycete colonies of the same color, shape and size on the

Medium and label them on Gao's solid culture medium No.1. The culture medium is incubated for seven days at 30 + 2°C using the pure culture method, and all samples are cultured in three portions (n=3). After a total of 6-9 times of purification,

Screening yielded several pure actinomycete colonies;

Re-screening: Inoculate several originally screened pure bacterial colonies into Gaoshi

No.1 liquid culture medium and incubate for five days at 135r/min and 30° C as

Seed solution. Add 6% of the seed solution to the denitrification medium by volume, shake and culture at 135 r/min and 30° C and determine the concentrations of

Nitrate and total nitrogen at 24 and 48 hours. Select the colony with the highest

total nitrogen removal efficiency as the optimal strain and name it strain LST24.

After sample sequencing, confirm that it is a pure strain and complete rescreening.

S2. Molecular biological identification of strains:

The strain LST24, which was re-screened, was subjected to a 16S rDNA

The genomic DNA of strain LST24 was analyzed using the

Omega DNA (Biotechnology, USA) kit and amplified using this as template for 16S rDNA. Primers: 27F (5 '- AGTTGATCMTGTTACTAG-3') and 14925 (5 '-

GGTTACCTGTTACGAT-3');

PCR reaction system (25 u L): Template DNA 20-50ng/u L, PCR Premium 12.5 u L, 27F (10) u M)1 u L.1492R (10) u M)1 u L.DdH20 9.5 y L. PCR program: 95 °C for 5

minutes, 94 °C for 30 seconds, 57 °C for 30 seconds, 72 °C for 90 seconds of 90228 72 °C for 10 minutes; 30 cycles. The purification and sequencing of the

PCR products were completed by the Bioengineering Company, the amplified

Sequences were uploaded to NCBI and subsequently compared to the GenBank database via BLAST for homology sequences.

The sequence length of strain LST24 is 1412 bp, as shown in the sequence table in Figure 6. After comparison, the sequence shows a high similarity of 99.93% with

Streptomyces phaeofaciens JCM 4814 (NCBI login number: NR 041126.1) in the NCBI

database that belongs to the genus Streptomyces. Call it Streptomyces phaeofaciens strain LST24 with highly efficient aerobic denitrification;

S3. Determination of the aerobic denitrification capacity of strains:

Inoculate LST24 seed solution at an inoculation rate of 1% (volume ratio) onto denitrifying liquid medium and incubate at 30 °C and 135 rpm in a shaker for 48 hours. During this period, samples are taken every three hours to determine the

Concentration of bacterial light density (OD600), total nitrogen (TN),

Ammonia nitrogen (NH4+- N), nitrate (NO3,N), nitrite (NO2,N) and dissolved organic

Carbon (DOC). As shown in Figure 2, the strain is in a slow phase at 0-9 hours and a logarithmic phase at 9-45 hours. After 45

After 48 hours of cultivation, the strain enters a stable phase and the concentration of DOC gradually decreases during the cultivation period. After 48 hours of cultivation, the

DOC removal rate of strain LST24 in an initial DOC medium of 150 mg/L was 91.5%. In addition, the Pearson correlation index confirmed a significant negative

Correlation between DOC concentration and cell growth (r=-0.937, P<0.001, n=17), indicating that carbon sources are energy and electron donors for

growth and metabolism of the LST24 strain. From Figure 2 and

Figure B shows that after 48 hours of cultivation, the nitrate removal rate was 99.12% and the total nitrogen removal rate was 97.18%. There was no significant

Accumulation of nitrite and ammonia nitrogen during the process. As seen above,

Strain LST24 obvious aerobic denitrification ability; In addition, as shown in Figure 3, the strain has a strong adaptability to the environment, and the optimal

Cultivation conditions for the strain are: starch as a carbon source, a

Carbon nitrogen ratio of 10, a rotation speed of 125 rpm and a neutral environment with a pH of 7;

S4. Application effect of expansion in slightly contaminated raw water:

Add the stock seed solution in a 5% volume ratio to the aerobic reactor, which adds the raw water of the landscape water body and the raw water of the water source reservoir. The oxygen peristaltic pump ensures continuous aeration of the reactor.

Monitoring the removal of COD Mn, ammonia nitrogen, nitrate, nitrite and

Total nitrogen in the reactor as well as the total number of cells and the OD 600 value after

Addition of seed fluid of strain LST24;

The treatment of landscape water raw water by the tribe is shown in Figure 4. The TN concentration decreased from 7.08 mg/L to 1.14 mg/L, resulting in a

TN removal rate of 83.62%. The COD-Mn concentration decreased from 7.01 mg/L to 0.67 mg/L, resulting in a COD-Mn removal rate of 90.33%. In addition, OD 600 showed an increasing trend in complex raw water environments: after the eighth day of reaction, the OD 600 value reached 0.16 and the total number of cells in the reactor increased by 9.5 times.

Useful effects

Compared to the state of the art, the advantageous effects of the present

Invention:

The aerobic denitrifying actinomycete strain LST24 with efficient nitrogen and

Carbon removal properties in the present invention may include the content of

Effectively reduce ammonia nitrogen, nitrate, nitrite and COD Mn in slightly polluted water and has great application potential in the in-situ treatment of other slightly polluted waters such as landscape waters and water source reservoirs. This has wide application possibilities for the development of denitrification bacteria or

Clarifying agents.

Illustrations

In order to provide a clearer explanation of the technical solution of the embodiments of the present

In order to give a better understanding of the invention, a brief introduction is given to the accompanying drawings, which are necessary for the description of the embodiments. It is obvious that the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technical personnel on the basis of these

Drawings can be obtained other accompanying drawings without any creative effort.

Figure 1 is a schematic diagram of the phylogenetic strain LST24 of the present invention;

Figure 2 shows the growth curve and the total degradation curve for dissolved organic

Carbon (DOC) of the strain LST24 of the present invention using

Nitrate as a nitrogen source; LUS05228

Figure 3 shows the aerobic denitrification performance of strain LST24 of the present

Invention when nitrate is the only source of nitrogen;

Figure 4 shows the aerobic denitrification performance of strain LST24 of the present

Invention using nitrate as the sole nitrogen source among various

Carbon sources, C/N, pH values and speed conditions;

Figure 5 shows the pollutant removal and cell growth of strain LST24 after

Addition to the raw water of the landscape water body according to the present invention;

Figure 6 shows the intended sequence representation of the actinomycete strain of the present invention;

Specific implementation method

Below you will find a clear and complete description of the technical solution in the

Embodiments of the present invention in conjunction with the attached

Drawings are provided. Obviously, the embodiments described are only a

Part of the embodiments of the present invention, not all of them Based on the embodiments of the present invention, all other embodiments obtained by ordinary technical personnel in the art without creative work fall within the scope of the present invention.

In order to facilitate the understanding of the present invention, a more comprehensive description is provided below with reference to the corresponding drawings. Several embodiments of the present invention are shown in the attached

The present invention may, however, be implemented in many different forms, not limited to the embodiments described herein. In

On the contrary, the purpose of providing these embodiments is to

To make the disclosure of the present invention more thorough and comprehensive.

It should be noted that when a component is referred to as being "fixed to" another component, it may be directly connected to another component or it may be a centered component. When a component is considered to be "connected" to another component, it may be directly connected to another component or both centering components may be present. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are for the purpose of identification only.

Illustration.

Unless otherwise defined, all technical and scientific terms used in this article have the same meanings as those generally used by

Those skilled in the art will understand the present invention. Di 905228

Terms used in the specification of the present invention in this article are for the purpose of describing particular embodiments only and are not intended to limit the present invention. The term "and/or" used in this article includes all combinations of one or more related listed

Elements.

The present invention offers a technical solution:

The application of an efficient aerobic denitrifying actinomycete strain in the

Treatment of slightly polluted water. The actinomycete strain is Streptomyces phaeofaciens LST24, and the effective sequence length of the 16SrRNA of the actinomycete strain

LST24 is 1412 bp, as shown in the sequence listing.

In this embodiment, the Streptomyces phaeofaciens strain LST24 is

Enrichment, cultivation, separation and purification from the overlying water of

preserved landscape water bodies.

In this embodiment, Streptomyces phaeofaciens strain LST24 is grown with nitrate as the sole nitrogen source.

In this embodiment, the Streptomyces phaeofaciens strain LST24 is suitable for

Nitrogen and carbon removal in lightly polluted waters.

In this embodiment, the micro-polluted water body refers to a

Water bodies with a concentration of pollutants below 10 mg/L (such as COD Mn,

Ammoniacal nitrogen, nitrate nitrogen and nitrite nitrogen).

In this embodiment, Streptomyces phaeofaciens strain LST24 is enriched and cultured from the overlying water sample of the landscape water body. It is then isolated on Gaoshi No.1 culture medium, screened for aerobic denitrification, and inoculated onto aerobic denitrification liquid culture medium for aerobic continuous cultivation.

In this embodiment, the aerobic continuous culture uses soluble starch as

Carbon source at a temperature of 30 °C; The inoculation amount of Streptomyces phaeofaciens LST24 is 1% of the volume of the aerobic denitrification liquid culture medium.

The application of an efficient aerobic denitrifying actinomycete strain in the

Treatment of slightly contaminated water involves the following specific steps:

S1. Recording and performance testing of strains;

Enrichment: on polycarbonate membrane (0.22) uw m) Filter 100 ml

Landscape water sample and immediately place the polycarbonate membrane on solid Gaoshi No. 1

Medium with 80 ppm K2Cr207. The medium was incubated for seven days at 30 + 2° C 909228

All samples were incubated in triplicate (n=3).

Among them, actinomycetes can penetrate the pores of polycarbonate membranes and grow on solid culture medium, while the addition of K2Cr207 increases the competitive

can inhibit the growth of bacteria and fungi on solid culture medium;

The formula of Gaoshi No.1 solid culture medium is: 0.5g/L KNO3, 0.01g/L NaCl, 0.01g/L

FeSO4, 0.5g/L KH2PO4, 0.5g/L MgSO4, 20g/L agar powder, 20g/L soluble starch, and the pH is adjusted to 7.2-7.4;

Preliminary screening: Take enriched and cultured Gao solid culture medium No.1, select dry actinomycete colonies of the same color, shape and size on the

Medium and label them on Gao's solid culture medium No.1. The culture medium is incubated for seven days at 30 + 2°C using the pure culture method, and all samples are cultured in three portions (n=3). After a total of 6-9 times of purification,

Screening yielded several pure actinomycete colonies;

Re-screening: Inoculate several originally screened pure bacterial colonies into Gaoshi

No.1 liquid culture medium and incubate for five days at 135r/min and 30° C as

Seed solution. Add 6% of the seed solution to the denitrification medium by volume, shake and culture at 135 r/min and 30° C and determine the concentrations of

Nitrate and total nitrogen at 24 and 48 hours. Select the colony with the highest

total nitrogen removal efficiency as the optimal strain and name it strain LST24.

After sample sequencing, confirm that it is a pure strain and complete rescreening.

S2. Molecular biological identification of strains:

The strain LST24, which was re-screened, was subjected to a 16S rDNA

The genomic DNA of strain LST24 was analyzed using the

Omega DNA (Biotechnology, USA) kit and amplified using this as template for 16S rDNA. Primers: 27F (5 '- AGTTGATCMTGTTACTAG-3') and 14925 (5 '-

GGTTACCTGTTACGAT-3');

PCR reaction system (25 u L): Template DNA 20-50ng/u L, PCR Premium 12.5 u L, 27F (10) u M)1 u L.1492R (10) u M)1 u L.DdH20 9.5 y L. PCR program: 95 °C for 5

minutes, 94 °C for 30 seconds, 57 °C for 30 seconds, 72 °C for 90 seconds and 72 °C for 10 minutes; 30 cycles. The purification and sequencing of the

PCR products were completed by the Bioengineering Company, the amplified

Sequences were uploaded to NCBI and subsequently compared to the GenBank database via BLAST for homology sequences. LU505228

The sequence length of strain LST24 is 1412 bp, as shown in the sequence table in Figure 6. After comparison, the sequence shows a high similarity of 99.93% with

Streptomyces phaeofaciens JCM 4814 (NCBI login number: NR 041126.1) in the NCBI

database that belongs to the genus Streptomyces. Call it Streptomyces phaeofaciens strain LST24 with highly efficient aerobic denitrification;

S3. Determination of the aerobic denitrification capacity of strains:

Inoculate LST24 seed solution at an inoculation rate of 1% (volume ratio) onto denitrifying liquid medium and incubate at 30 °C and 135 rpm in a shaker for 48 hours. During this period, samples are taken every three hours to determine the

Concentration of bacterial light density (OD600), total nitrogen (TN),

Ammonia nitrogen (NH4+- N), nitrate (NO3,N), nitrite (NO2,N) and dissolved organic

Carbon (DOC). As shown in Figure 2, the strain is in a slow phase at 0-9 hours and a logarithmic phase at 9-45 hours. After 45

After 48 hours of cultivation, the strain enters a stable phase and the concentration of DOC gradually decreases during the cultivation period. After 48 hours of cultivation, the

DOC removal rate of strain LST24 in an initial DOC medium of 150 mg/L was 91.5%. In addition, the Pearson correlation index confirmed a significant negative

Correlation between DOC concentration and cell growth (r=-0.937, P<0.001, n=17), indicating that carbon sources are energy and electron donors for

growth and metabolism of the LST24 strain. From Figure 2 and

Figure B shows that after 48 hours of cultivation, the nitrate removal rate was 99.12% and the total nitrogen removal rate was 97.18%. There was no significant

Accumulation of nitrite and ammonia nitrogen during the process. As seen above,

Strain LST24 obvious aerobic denitrification ability; In addition, as shown in Figure 3, the strain has a strong adaptability to the environment, and the optimal

Cultivation conditions for the strain are: starch as a carbon source, a

Carbon nitrogen ratio of 10, a rotation speed of 125 rpm and a neutral environment with a pH of 7;

S4. Application effect of expansion in slightly contaminated raw water:

Add the stock seed solution in a 5% volume ratio to the aerobic reactor, which adds the raw water of the landscape water body and the raw water of the water source reservoir.The oxygen peristaltic pump ensures continuous aeration of the reactor.

Monitoring the removal of COD Mn, ammonia nitrogen, nitrate, nitrite and

Total nitrogen in the reactor as well as the total number of cells and the OD 600 value after 09228

Addition of seed fluid of strain LST24;

The treatment of landscape water raw water by the tribe is shown in Figure 4. The TN concentration decreased from 7.08 mg/L to 1.14 mg/L, resulting in a

TN removal rate of 83.62%. The COD-Mn concentration decreased from 7.01 mg/L to 0.67 mg/L, resulting in a COD-Mn removal rate of 90.33%. In addition, OD 600 showed an increasing trend in complex raw water environments: after the eighth day of reaction, the OD 600 value reached 0.16 and the total number of cells in the reactor increased by 9.5 times.

In practice, the aerobic denitrifying actinomycete strain LST24 was identified as Streptomyces phaeofaciens (NCBI registration number: OM980672), which belongs to the genus

Streptomyces (Streptomyces sp.) and efficient nitrogen and

The Streptomyces phaeofaciens strain LST24, which has high nitrogen and carbon removal efficiency, was

Key Laboratory of Northwest Water Resources and Environmental Ecology, Xi'an University of

Architecture and Technology on December 25, 2021. The process form of application of Streptomyces phaeofaciens strain LST24, which has high efficiency in nitrogen and

Carbon removal is aerobic aeration, in which the seminal fluid of the stem

LST24 is inoculated into slightly contaminated raw water samples. And the water sample was subjected to

Aeration treatment — subjected to the dosage of aerobic denitrifying

Actinomycete strain LST24, which efficiently uses nitrogen and

carbon removal properties is 5% of the reactor volume. The aerobic denitrifying actinomycete strain LST24, which has efficient nitrogen and

carbon removal properties, can effectively reduce the content of ammonia nitrogen,

Reduce nitrate, nitrite and COD Mn in slightly polluted water and has great

Potential for in-situ treatment of other lightly polluted waters such as

Landscape water bodies and water source reservoirs. This has broad

Application possibilities for the development of denitrification bacteria or clarifiers.

The above is only a preferred specific implementation of the present invention, but the scope of the present invention is not limited thereto. Any technical

Personnel familiar with the technical field, which within the scope of the disclosed

Technology equivalent replacements or changes based on the technical solution and inventive concept of the present invention should be included in the

fall within the scope of the present invention.

Claims (8)

PATENT CLAIMS 0505228 1. An efficient aerobic denitrifying actinomycete strain, characterized in that the actinomycete strain is Streptomyces phaeofaciens LST24 and the effective sequence length of the 16SrRNA of the actinomycete strain LST24 is 1412 bp as shown in the sequence listing. 2. A highly efficient aerobic denitrifying actinomycete strain according to claim 1, characterized in that the Streptomyces phaeofaciens LST24 is obtained by enrichment, cultivation, separation and purification from overlying water of landscape waters. 3. A highly efficient aerobic denitrifying actinomycete strain according to claim 1, characterized in that the Streptomyces phaeofaciens LST24 is grown with nitrate as the sole nitrogen source... 4. A highly efficient aerobic denitrifying actinomycete strain according to claim 1, characterized in that Streptomyces phaeofaciens LST24 is suitable for nitrogen and carbon removal in slightly polluted waters. 5. A highly efficient aerobic denitrifying actinomycete strain according to claim 1, characterized in that the slightly polluted water body refers to a water body with a pollutant concentration below 10 mg/L (such as COD Mn, ammonia nitrogen, nitrate nitrogen and nitrite nitrogen). 6. An efficient aerobic denitrifying actinomycete strain according to claim 1, characterized in that the Streptomyces phaeofaciens LST24 is enriched and cultured from a water sample overlying a landscape water body, sequentially separated on Gao's No.1 culture medium, screened for aerobic denitrification, and inoculated on an aerobic denitrifying liquid culture medium for aerobic continuous cultivation. 7. An efficient aerobic denitrifying actinomycetes strain according to claim 1, characterized in that the aerobic continuous cultivation uses soluble starch as a carbon source at a temperature of 30'C; the inoculation amount of Streptomyces phaeofaciens LST24 is 1% of the volume of the aerobic denitrifying liquid culture medium. 8. The use of an efficient aerobic denitrifying actinomycete strain according to any one of claims 1-7 in the treatment of slightly polluted water, the specific steps being as follows: S1. Detection and performance testing of strains; enrichment: on polycarbonate membrane (0.22) uw m) Filter 100 ml Landscape water sample and immediately place the polycarbonate membrane on Gaoshi No/°05228 solid medium containing 80ppm K2Cr207, the medium was incubated at 30 + 2°C for seven days, all samples were incubated in triplicate (n=3), among them, actinomycetes can penetrate the pores of polycarbonate membranes and grow on solid culture medium, while the addition of K2Cr207 can inhibit the competitive growth of bacteria and fungi on solid culture medium; the formula of Gaoshi No.1 solid culture medium is: 0.5g/L KNO3, 0.01g/L NaCl, 0.01g/L FeSO4, 0.5g/L KH2PO4, 0.5g/L MgSO4, 20g/L agar powder, 20g/L soluble starch, and the pH is adjusted to 7.2~7.4; Preliminary screening: Take enriched and cultured Gao solid culture medium No.1, select dry actinomycete colonies of the same color, shape and size on the medium and mark them on Gao's No.1 solid culture medium; the culture medium is incubated at 30 + 2°C for seven days by the pure culture method, and all samples are cultured in three portions (n=3); after a total of 6-9 times of purification, several pure actinomycete colonies were obtained from the first screening; re-screening: inoculate several originally sieved pure bacterial colonies into Gaoshi No.1 liquid culture medium and incubate at 135r/min and 30°C for five days as seed solution; add 6% of the seed solution to the denitrification medium by volume, shake and culture at 135r/min and 30°C, and determine the concentrations of nitrate and total nitrogen at 24 and 48 hours; select the colony with the highest total nitrogen removal efficiency as the optimal strain and name it strain LST24; after sample sequencing, it is confirmed to be a pure strain and complete the rescreening; S2. Molecular biological identification of strains: the strain LST24, which was re-screened, was subjected to 16S rDNA gene sequence analysis; the genomic DNA of the strain LST24 was extracted using the Omega DNA (Biotechnology, USA) kit and amplified using it as a template for 16S rDNA, primer: 27F (5 '- AGTTGATCMTGTTACTAG-3') and 14925 (5 '- GGTTACCTGTTACGAT-3"); PCR reaction system (25 u L): Template DNA 20-50ng/u L, PCR Premium 12.5 u L, 27F (10) 4 M)1 u L.1492R (10) u M)1 u L.DdH20 9.5 u L. PCR program: 95 °C for 5 minutes, 94 °C for 30 seconds, 57 °C for 30 seconds, 72 °C for 90 seconds and 72 °C for 10 minutes; 30 cycles amplification; the purification and sequencing of the PCR products was completed by the Bioengineering Company, the amplified 505228 sequences were uploaded to NCBI, and then compared with the GenBank database via BLAST for homology sequences; the sequence length of strain LST24 is 1412 bp, as shown in the sequence table in Figure 6; after comparison, the sequence has a high similarity of 99.93% with Streptomyces phaeofaciens JCM 4814 (NCBI login number: NR 041126.1) in the NCBI database, which belongs to the genus Streptomyces; call it the Streptomyces phaeofaciens strain LST24 with high-efficiency aerobic denitrification; S3. Determination of aerobic denitrification ability of strains: inoculate LST24 seed solution with an inoculation amount of 1% (volume ratio) onto denitrifying liquid medium and incubate at 30 °C and 135 rpm in a shaker for 48 hours; during this period, samples are taken every three hours to measure the concentration of bacterial light density (OD600), total nitrogen (TN), ammonia nitrogen (NH4+- N), nitrate (NO3,N), nitrite (NO2,N) and dissolved organic carbon (DOC); as shown in Figure 2, the strain is in a slow phase at 0-9 hours and a logarithmic phase at 9-45 hours; after 45 hours of cultivation, the strain enters a stable phase, and the concentration of DOC gradually decreases during the cultivation period; after 48 hours of cultivation, the DOC removal rate of strain LST24 in an initial DOC medium of 150mg/L was 91.5%; in addition, Pearson correlation index confirmed a significant negative correlation between DOC concentration and cell growth (r=-0.937, P<0.001, n=17), indicating that carbon sources can provide energy and electron donors for the growth and metabolism of strain LST24; from Figure 2 and Figure B, it can be seen that after 48 hours of cultivation, the nitrate removal rate was 99.12%, and the total nitrogen removal rate was 97.18%; there was no significant accumulation of nitrite and ammonia nitrogen during the process; as seen above, strain LST24 has obvious aerobic denitrification ability; In addition, as shown in Figure 3, the strain has strong environmental adaptability, and the optimal cultivation conditions for the strain are: starch as a carbon source, a carbon nitrogen ratio of 10, a rotation speed of 125 rpm, and a neutral environment with a pH of 7; S4. Application effect of dilation in slightly polluted raw water: Add the stock seed solution in a 5% volume ratio to the aerobic reactor containing the raw water of the landscape water body and the raw water of the water source reservoirs; the oxygen peristaltic pump ensures continuous 99228 aeration of the reactor; monitoring the removal of COD Mn, ammonia nitrogen, nitrate, nitrite and total nitrogen in the reactor as well as the total number of cells and OD 600 value after addition of the seed liquid of strain LST24; the treatment of landscape water raw water by the strain is shown in Figure 4; the TN concentration decreased from 7.08 mg/L to 1.14 mg/L, resulting in a TN removal rate of 83.62%; the COD-Mn concentration decreased from 7.01 mg/L to 0.67 mg/L, resulting in a COD-Mn removal rate of 90.33%; in addition, OD 600 showed an increasing trend in complex raw water environments: after the eighth day of reaction, the OD 600 value reached 0.16 and the total number of cells in the reactor increased by 9.5 times.