KR100893725B1 - Microbial cultures containing the self aggregates and free living form of bacillus thuringiensis enb2 kctc 11394bp - Google Patents

Abstract

Provided is Bacillus thuringiensis EnB2(KCTC 11394BP) which can biodegrade with sewage and waste water and high-concentration organic waste water. Bacillus thuringiensis EnB2(KCTC 11394BP) strain has capability of improving formation of floc and precipitation of sludge. The Bacillus thuringiensis EnB2 strain has rDNA base sequence of SEQ ID NO:1. A microbial agent for treating sewage and waste water includes a culture fluid of the Bacillus thuringiensis EnB2. The microbial agent has an improved function of precipitation.

Description

Microbial cultures containing the self aggregates and free living form of Bacillus thuringiensis EnB2 KCTC 11394BP}

The present invention relates to a new strain Bacillus thuringiensis EnB2 KCTC 11394BP, a culture medium and a microbial agent effective for treating sewage water, including the same.

At present, various sewage treatment facilities operating in Korea are difficult to maintain the normal type of flocs that have good stereoscopic and consolidation characteristics in the aeration tank due to the rapid change of raw water inflow and load concentration.

Moreover, sludge that cannot maintain normal sedimentation can be easily dismantled by weak load fluctuations and can lead to poor water quality. In particular, when the sedimentation of sludge is deteriorated, it is difficult to separate solid-liquid in the sedimentation tank, thereby increasing the SS (Suspended Solid), thereby increasing the turbidity of the effluent.

In addition, the reduction of mixed liquor suspended solids (MLSS) due to sludge overflow makes it difficult to operate a normal wastewater treatment plant. In this case, only a fraction of the normal wastewater treatment of the treatment plant can be treated, and in extreme cases, the plant may be shut down.

Swelling of sewage treatment facilities due to sludge settling deterioration is mostly caused by filamentous microorganisms, but mucus or non-cerebrolytic bulking, which can be caused by microorganisms in Zoglea, has not been identified. It is difficult to operate the treatment facility. In particular, non-cephaly swelling occurs frequently in treatment facilities where high concentrations of sugar are introduced, and variously occurs in municipal sewage treatment facilities.

It takes months to recover this deteriorated sludge settling and there is no known good solution. Organic sedimentation agents can be used to temporarily recover the sludge settling properties, but prolonged use of the sedimentation agents deteriorates the treatment efficiency of the treatment facility by eliminating the biological activity of the sludge.

Another solution is to seed the sludges of other treatment facilities and replace the sludges which have degraded the existing sedimentation. It has the potential to cause problems.

On the other hand, Bacillus Shuringiensis produces a proteinaceous insecticidal δ-endotoxins of proteinaceous insecticide known as BT toxin when spores are formed by gram-positive bacteria. The BT toxin is currently developed as a microbial pesticide for moths, butterflies, flies and mosquitoes, but there are no examples of wastewater treatment.

Therefore, the inventors of the present invention isolated and identified Bacillus shrinziensis EnB2 in flocs in the aeration tank of a biological treatment plant where floc sedimentation of the sewage treatment plant in Korea lasted longer than that of other treatment plants. The new strain Bacillus shrinziensis EnB2 KCTC 11394BP was found to promote its own floc formation as a single species under the control of dissolved oxygen and pH.

Accordingly, the present invention improves sludge sedimentation and treatment efficiency, such as BOD, COD, and TN, and sewage and high concentration organics containing organic substances having low solubility in water such as some endocrine barriers (ECDs) such as plastic plasticizers. The objective is to provide a new strain Bacillus shrinziensis EnB2 KCTC 11394BP that can rapidly biodegrade wastewater.

In addition, the present invention is another object to provide a Bacillus Shurinjiensis EnB2 KCTC 11394BP culture and a microbial preparation comprising the same.

As an example for solving the above problems, the present invention is characterized by the Bacillus thuringiensis EnB2 KCTC 11394BP strain with improved floc forming ability and sludge sedimentation improving ability.

As another example for solving the above problems, the present invention includes the culture solution of Bacillus thuringiensis EnB2 KCTC 11394BP.

As another example for solving the above problems, the present invention includes a microbial agent for treating sewage water comprising a culture solution of Bacillus thuringiensis EnB2 KCTC 11394BP.

Hereinafter, the present invention will be described in detail.

Bacillus Shurinjiensis EnB2 KCTC 11394BP, a new strain of the present invention, was identified and separated for the first time by the present inventors, and NA (Nutrient Agar) and TSA (Tryptic Soy Agar) in the field sludge having the highest sedimentation property of the sludge among sewage wastewater treatment facilities. ), Single strain was isolated using R2A medium, and the isolated single strain was analyzed by molecular genetic method by 16S rDNA sequence retrieval. As a result, Bacillus thuringiensis IAM 12077 and the standard strain were identified. The 16r DNA sequence was confirmed to be 99.9% similar new strains (see SEQ ID NO: 1 and FIG. 3).

The present inventors named the purely isolated new strain Bacillus thuringiensis EnB2, deposited on September 29, 2008 in the Korea Collection of Type Culture (KCTC) Biotechnology Center Was given accession number KCTC 11394BP (see Fig. 5). Hereinafter, EnB2 ”refers to the Bacillus shringiensis EnB2 KCTC 11394BP.

The EnB2 medium is EnB2 medium (glucose 60g / L, yeast extract 0.5g / L, magnesium sulfate 0.2g / L, potassium monophosphate 0.9g / L, salt 0.1g / L, sodium succinate 3g / L, sodium acetate 3g Incubate with 0.2 ppm dissolved oxygen and pH 6.9. In order to promote floc formation of EnB2 in the culture, the dissolved oxygen is increased to 4 ppm and the pH is maintained at 9.5.

In case of sewage treatment facilities with low concentration of influent water, it is difficult to maintain MLSS (Mixed Liquor Suspended Solid), because it is difficult to increase the number of free swimming bacteria that are sludge generation sources, and the existing flocs are capitalized and sludge dismantling Because it is going.

EnB2 of the present invention can be used as a target microbial agent that is put in order to maintain the sludge in a treatment facility that is frequently sludge assetization and dismantling due to the organic load is low, EnB2 is added to the filamentous body when it is put into a number of wastewater treatment plants having filamentous bulking Attachment causes filamentous microorganisms to fuse into the floc, thereby promoting flocculation with good compaction and conformation.

The self-floc formed during the culturing of EnB2 independently forms a stable floc or fuses with existing filamentous microorganisms to form floc with excellent sedimentation.

Unlike general microbial preparations, the culture medium of EnB2 includes a floc of EnB2 formed by adjusting pH and dissolved oxygen during incubation with EnB2 in a free-flowing form. Free-floating EnB2 promotes floc formation of free-living microorganisms that are already present in the aeration tank by quickly removing the organics remaining when administered into the aeration tank, and the floc in the EnB2 culture adheres to sludge that is weak in compactness and conformation Independently, flocs having good settling properties are formed in the aeration tank.

Therefore, the two types of bacterial cultures contained in the EnB2 culture solution are introduced into the aeration tank to promote the solidification and consolidation of flocs at the same time and to quickly remove the undissolved organics, thereby greatly shortening the time required for normalization of the wastewater treatment facility. Therefore, the problem of sedimentation deterioration can be easily solved when the EnB2 culture solution is administered to the sewage treatment facility where sedimentation deterioration has occurred.

The floc of EnB2 formed by dissolving oxygen and pH in the process of culturing EnB2 at a high concentration shows excellent MLSS (Mixed Liquor Suspended Solid) production promoting ability, and increases the stericity and consolidation of the sludge. In contrast to conventional microbial preparations consisting of free-flowing bacteria, the flocs formed during the culturing of EnB2 have already been added to the aeration tank of floc and Bacillus-shringiensis EnB2 free-flowing bacteria. When it is combined with existing sludge quickly, MLSS can be easily maintained, and the sludge settling property can be improved.

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In addition, EnB2 of the present invention promotes biofilm formation in various suspended media media, greatly increasing the removal efficiency of BOD, COD, TN, and also has a great effect on the treatment of high concentration organic wastewater, such as beverage reclaimed wastewater.

As described above, Bacillus shrinziensis EnB2 KCTC 11394BP, a new strain first disclosed by the inventor of the present invention, may promote or inhibit the formation of its own floc in a culture medium by adjusting dissolved oxygen and pH, and these flocs are treated in sewage water. When introduced into the facility, it exhibits properties that promote sludge settling and MLSS production faster than cultures consisting solely of free-flowing Bacillus Schrinziensis EnB2.

According to the new bacterium EnB2 of the present invention, the biological floc of the treatment facility in which sludge is dismantled due to the inflow of high concentration organic matter and the sludge assetization due to the long-term inflow of low concentration organic matter can be quickly promoted, and the sedimentability due to low concentration and overload Can quickly improve the deterioration. In addition, sludge replacement in the treatment plant can be easily carried out with the introduction of EnB2, which can greatly help the normal treatment plant operation by quickly removing organic matter and nitrogen remaining in the aeration tank.

In addition, the flocks (self aggregates) and free-flowing bacteria contained in the culture of EnB2, a new strain of the present invention, may be subjected to load fluctuations, inflow of toxic substances, sludge disintegration, filamentous bulking, or jugrea ( Zooglea spp.), Such as nonfilamentous bulking can be expected to easily solve the problem.

In addition, the new strain EnB2 of the present invention promotes biofilm formation in a variety of suspended bed media such as the biological oxygen demand (Biological Oxygen Demand, BOD), chemical oxygen demand (COD) and total nitrogen (TN) of the wastewater treatment plant. Significantly increase the treatment efficiency and have a great effect on the treatment of high concentration organic wastewater such as beverage reclaimed wastewater.

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Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1 Isolation, Identification and Growth Characteristics of EnB2

(1) Isolation of Bacillus Shuringiensis EnB2

The strain of the present invention used sludge in the aeration tank of the sewage treatment plant located in Chuncheon, Gangwon-do, as a sample for separation, and the sewage treatment plant has a spherical floc shape that is excellent in consolidation for many years, unlike other treatment facilities. It was a maintained treatment facility.

Sludge was collected by centrifugation (2,000 g), and homogenized with a homogenizer for 1 minute by adding 0.85% physiological saline solution, followed by mixing at 350 rpm in a vertical stirrer. Subsequently, serial dilutions were diluted in nutrient agar, TSA, and R2A to spread the medium, and colonies with the highest colony count were recovered from the three medium and subcultured on the same medium. The first selected strains were inoculated in the same liquid medium and incubated at 150 rpm for 25 days at 25 ° C. for the first time, strains which grew to form flocks (self aggregates) were secondarily selected. Among the second screened samples, the floc of Bacillus shringiensis EnB2 was the most ideal. The colonies that appeared when the Bacillus shringiensis EnB2 was incubated in nutrient agar were similar to the colonies of typical Bacillus microorganisms.

(2) Identification of Bacillus Shuringiensis EnB2

In order to confirm the taxonomic location of Bacillus shrinziensis EnB2, it was first confirmed that Bacillus shrinziens EnB2 was Gram-positive bacteria by performing gram staining to investigate morphological characteristics. Bacillus shrinziensis EnB2 had a form of about 1.3㎛ bacilli [Fig. 1A], a Gram-positive strain similar to the characteristics of common Bacillus bacteria, and formed a matt white colony on a plate medium [Fig. A]. It can be seen that the floc is formed in the flask liquid culture liquid [FIG. 2B], and it can be confirmed that a large amount of floc is formed during the mass culture using the fermenter [FIG. 2C] and the floc formed in FIG. 2D. A micrograph of the is shown.

Example 2 Biochemical Characteristics and Carbon Sources of Bacillus Shuringiensis EnB2

Table 1 summarizes the biochemical characteristics of Bacillus shringiensis EnB2, and Table 2 summarizes the available carbon sources.

TABLE 1

Biochemical Characterization of Bacillus Shuringiensis EnB2 Oxidase positivity Arginine dehydrolase positivity Catalase positivity Beta galactosidase positivity Nitrate reducing ability positivity Esculin hydrolysis positivity Indole generation voice Urease voice Acid production from glucose positivity

TABLE 2

Use of carbon source of Bacillus Schringensis EnB2 glucose positivity Pyruvic acid positivity Arabinos positivity Phenyl acetate voice Mannitol positivity Benzoic acid positivity N-acetylglucosamine positivity Glycerol positivity Maltose positivity Xylose positivity Gluconic Acid positivity Fructose positivity Carnic acid positivity Sucrose positivity Adipic acid voice dextrin positivity Malic acid positivity gelatin voice Citric acid positivity Starch positivity

Example 3 Sequencing of Bacillus shringiensis EnB2

The sequencing of Bacillus shrinziensis EnB2 was analyzed by 16s rDNA sequence sequencing, and the analytical institution is Macrogen. The state of the sample was commissioned in a plate medium with Bacillus Shurinjiensis EnB2 colony, and as the request details, PCR products by Extraction-gDNA and PCR Amplication were analyzed through 10 sequencing reactions.

The primers used in the analysis are divided into universal primers as follows.

27F: 5'-AgAgTTTgATCMTGGCTCAg-3 '

1492R: 5'-TACggYTACCTTgTTACgACTT-3 '

The 16s rDNA sequencing results of Bacillus shrinziensis EnB2 are described in the attached SEQ ID NO. 1, and the phylogenetic results are derived from the tree tree according to the neighbor-joining method to which the Juke-Cantor model is applied. (phylogenetic tree) results are shown in FIG. 3.

Bacillus Shurinjiensis EnB2 is the base sequence [SEQ ID NO: 1] is the easy-taxison server (EzTaxon server, Chun, J., Lee, J.-H., Jung, Y., Kim, M., Kim, S., Kim , BK & Lim, YW (2007) .EzTaxon: a web-based tool for the identification of prokaryotes based on 16S ribosomal RNA gene sequences.Int J Syst Evol Microbiol 57, 2259-2261.) Bacillus shrinjiensis was classified [Fig. 4], the inventors of the present invention named the isolate "Bacillus thuringiensis (EnB2)", September 29, 2008 Biotechnology Center of Korea Biotechnology Research Institute ( KCTC) was granted accession number KCTC 11394BP. A trust certificate was attached to FIG. 5.

Example 4 Efficacy Test at the Laboratory Level of Bacillus Shuringiensis EnB2

(1) Preparation of culture medium of Bacillus shringiensis EnB2

EnB2 medium (glucose 60 g / L, yeast extract 0.5 g / L, magnesium sulfate 0.2 g / L, potassium monophosphate 0.9 g / L, salt 0.1 / L, sodium succinate 3 g / L, sodium acetate 3 g / L Flock formation of Bacillus shrinziensis EnB2 was observed while changing pH and dissolved oxygen (DO). The floc formation was measured by absorbance (Optical Density, OD) the height of the settled floc after standing the culture solution for 5 minutes in a 100 ml mass cylinder, the results are shown in FIG.

According to FIG. 6, it can be seen that floculation in EnB2 culture is most promoted under the conditions of pH 9.5 and 4 ppm of dissolved oxygen.

(2) jar test for improvement of sedimentation properties of non-cephaly expanded sludge using Bacillus Schrinziensis EnB2

If the non-flattening sludge was secured at a beverage wastewater treatment plant located in Anseong, Gyeonggi-do, the jar test device was installed next to the beverage wastewater treatment plant aeration tank and tested. The jar test device consisted of six rectangular small aeration tanks made of stainless steel with an effective capacity of 46 liters. Each tank was equipped with one brower with an air supply of 40 liters per minute. At the time of the experiment, the sludge of the beverage wastewater treatment plant exhibited non-flattening phenomena, and the MLSS was about 3,500 mg / l and the sludge sedimentation was little. A small experimental aeration tank was introduced into the wastewater treatment plant and operated in the same manner as the treatment plant. Dissolved oxygen was maintained at 2-3 ppm, 1 liter of sludge was discarded each day, raw water was adjusted to 35 ml / min / day, and free-type culture medium and floc-type culture medium were administered to the experimental aeration tank, respectively. Bacillus subtilis was used. In order to equally control the amount of each microbial culture, the supernatant was removed by centrifugation of 500 ml of the culture, and the weight of the precipitated bacteria was measured to prepare the cells of the bacteria to be used in the experiment. The same amount of bacteria prepared in this way were administered 10 ml / day 5 times a day (217 ppm), and was not returned.

The jar test results are shown in FIG. 7, and according to FIG. 7, the free-streaming type in the EnB2 culture was also excellent in improving the sludge settling property, but the floc type culture medium had a greater improvement effect on the sludge settling property. have.

In the jar test experiment, the change of sludge indicating the degree of sedimentation improvement of non-flattening sludge by administration of the culture solution of Bacillus shrinziensis ENB2 was observed under a microscope, and the results are shown in FIG. 8.

Example 5 COD Removal of EnB2 Concentrated Organic Wastewater

COD removal rate and SV ₃₀ . The experiment was started after abandoning the EnB2 floc culture solution in 1000 ppm each sample for 24 hours. Abandoned wastewater was administered for 3 days with 1,000 ppm / day of EnB2 floc culture, left for 24 hours after SV ₃₀ measurement on the last day, and the supernatant was taken to analyze the COD. The results are shown in Table 3 below.

After centrifuging the same sample analyzed at COD at 15,000rpm, COD was measured again. In this experiment by bacteria, overwidth means maximum strength of small air supply device and internal circulation means stirring using small underwater pump.

TABLE 3

EnB2 Dose (ppm / day) COD (ppm) COD removal rate (%) SV ₃₀ (%) Before treatment After treatment Centrifugation 24hr elapsed 48hr elapsed 72hr elapsed Sample 1 1,000 50,400 9,500 ¹⁾ 8,100 81 350 380 430 ⁵⁾ Sample 2 0 50,400 15,700 ²⁾ 15,100 69 250 300 300 Sample 3 1,000 50,400 17,000 ³⁾ 16,400 66 200 220 260 Sample 4 0 50,400 21,000 ⁴⁾ 20,600 58 180 200 200 Sample 1: administration of excessive EnB2, sample 2: administration of excessive EnB2, sample 3: administration of internal circulation EnB2, sample 4: administration of internal circulation EnB2

As shown in Table 3, according to the sample which passed 72 hours, the treatment efficiency was improved by 12% when the EnB2 floc culture solution was administered to the beverage returning wastewater. You can see that it appears.

Example 6 Administration of EnB2 Flock Culture Solution for 30 Days at a Beverage Wastewater Treatment Facility

TABLE 4

division Third Party Microbial Activation EnB2 floc culture Wastewater Treatment Volume (㎥) Raw water COD (mg / L) Treated water COD (mg / L) SV ₃₀ (%) Wastewater Treatment Volume (㎥) Raw water COD (mg / L) Treated water COD (mg / L) SV ₃₀ (%) Primary 542 770 114 65 790 974 92 50 Secondary 558 920 123 65 900 1051 82 45 3rd 1044 1000 105 70 1020 939 72 45 4th 1161 1670 152 75 1020 953 82 45 5th 1190 1502 138 80 1235 836 84 50 6th 1265 1093 109 80 1455 1084 87 55 7th 1229 1040 88 70 1090 953 94 55 Average 1006.3 1030.4 111.9 66.3 1028.7 1025.8 84.7 49.3

As shown in Table 4, compared with the administration of the third-party microbial activator and EnB2 floc culture solution for 30 days, respectively. In the case of administration of EnB2 floc culture, wastewater treatment and raw water COD removal efficiency increased 2.23% and 24.31%, respectively.

Example 7 Enhancement of Washing Water Treatment Efficiency of LCD Panel Production Plant by Promoting Biofilm Formation of Bacillus Schrinziensis EnB2 Culture

TABLE 5

Before administering EnB2 culture After administration of EnB2 culture BOD COD TOC TN BOD COD TOC TN enemy 61.5 62 35.4 17.22 64.5 57 20.6 14.83 Treated water 24 34 12 12.6 1.8 6.8 3.6 5.288

As shown in Table 5, when the Bacillus Shurinjiensis EnB2 culture solution is added, it can be seen that the BOD, COD, TOC (Total Organic Cabon) and TN removal efficiency of the LCD panel wash water is improved, which is a sponge-type fluidized bed The Bacillus Shuringiensis EnB2 culture solution administered to the fluidized bed media of the LCD panel production plant operated by the media appears to increase the removal rate of BOD, COD, and TN in the wash water by forming a biofilm inside the media. After administration of EnB2 culture, it can be seen that a large amount of biofilm is formed inside the fluidized bed media.

On the other hand, scanning electron micrographs of the flocs before (A) and after (B) administration of EnB2 culture are shown in FIG. 8.

Figure 1 is a Gram-stained photograph of Bacillus Shurinziensis EnB2 (navy blue), red bacillus shows a control E. coli (A), a scanning electron micrograph (B) of Bacillus Shurinjiensis EnB2.

FIG. 2 shows a matt colony of Bacillus shringiensi EnB2, floculation in a flask liquid culture (B), floculation (C) in a bulk culture with a fermenter, and micrograph (D) of the floc.

3 is Bacillus A phylogenetic tree showing a phylogenetic relationship between standard strains belonging to the genus and Bacillus thuringiensis EnB2 isolated from Korea was prepared by Naver-Joining method using a 16S rDNA sequence (about 1,300 bp). Numbers are tree tree support (more than 50%)].

4 is a result of homology analysis of the 16s rDNA sequence of Bacillus shringiensis EnB2 using EzTaxon server.

Figure 5 is a microbial entrustment of Bacillus shringiensis EnB2 KCTC 11394BP of the present invention.

FIG. 6 is a graph showing the change in floc formation according to pH and dissolved oxygen change of Bacillus shringiensis EnB2 KCTC 11394 BP using EnB2 medium.

7 is a graph showing the improvement effect on the sludge settling properties of free-flowing EnB2 bacteria in the EnB2 culture, but the floc type EnB2 bacteria than the free-streaming type for sludge settling.

Fig. 8 is a photograph showing the degree of sedimentation improvement of non-flattening sludge by administration of a culture solution of Bacillus shringiensis ENB2.

9 (A) shows the scanning electron micrograph before administration of EnB2 floc culture solution, and (B) shows the scanning electron micrograph after administration of EnB2 floc culture solution.

<110> EnB CO., LTD. <120> Microbial cultures containing the self aggregates and free living          form of Bacillus thuringiensis EnB2 KCTC 1139BP <160> 1 <170> KopatentIn 1.71 <210> 1 <211> 1482 <212> DNA <213> Bacillus thuringiensis EnB2 KCTC 11394BP <400> 1 ctcaggatga acgctggcgg cgtgcctaat acatgcaagt cgagcgaatg gattnagagc 60 ttgctctcat gaagttagcg gcggacgggt gagtaacacg tgggtaacct gcccataaga 120 ctgggataac tccgggaaac cggggctaat accggataac attttgaact gcatggttcg 180 aaattgaaag gcggcttcgg ctgtcactta tggatggacc cgcgtcgcat tagctagttg 240 gtgaggtaac ggctcaccaa ggcaacgatg cgtagccgac ctgagagggt gatcggccac 300 actgggactg agacacggcc cagactccta cgggaggcag cagtagggaa tcttccgcaa 360 tggacgaaag tctgacggag caacgccgcg tgagtgatga aggctttcgg gtcgtaaaac 420 tctgttgtta gggaagaaca agtgctagtt gaataagctg gcaccttgac ggtacctaac 480 cagaaagcca cggctaacta cgtgccagca gccgcggtaa tacgtaggtg gcaagcgtta 540 tccggaatta ttgggcgtaa agcgcgcgca ggtggtttct taagtctgat gtgaaagccc 600 acggctcaac cgtggagggt cattggaaac tgggagactt gagtgcagaa gaggaaagtg 660 gaattccatg tgtagcggtg aaatgcgtag agatatggag gaacaccagt ggcgaaggcg 720 actttctggt ctgtaactga cactgaggcg cgaaagcgtg gggagcaaac aggattagat 780 accctggtag tccacgccgt aaacgatgag tgctaagtgt tagagggttt ccgcccttta 840 gtgctgaagt taacgcatta agcactccgc ctggggagta cggccgcaag gctgaaactc 900 aaaggaattg acgggggccc gcacaagcgg tggagcatgt ggtttaattc gaagcaacgc 960 gaagaacctt accaggtctt gacatcctct gaaaacccta gagatagggc ttctccttcg 1020 ggagcagagt gacaggtggt gcatggttgt cgtcagctcg tgtcgtgaga tgttgggtta 1080 agtcccgcaa cgagcgcaac ccttgatctt agttgccatc attaagttgg gcactctaag 1140 gtgactgccg gtgacaaacc ggaggaaggt ggggatgacg tcaaatcatc atgcccctta 1200 tgacctgggc tacacacgtg ctacaatgga cggtacaaag agctgcaaga ccgcgaggtg 1260 gagctaatct cataaaaccg ttctcagttc ggattgtagg ctgcaactcg cctacatgaa 1320 gctggaatcg ctagtaatcg cggatcagca tgccgcggtg aatacgttcc cgggccttgt 1380 acacaccgcc cgtcacacca cgagagtttg taacacccga agtcggtggg gtaacctttt 1440 tggagccagc cgcctaaggt gggacagatg attggggtga at 1482  

Claims (6)

Bacillus thuringiensis EnB2 KCTC 11394BP strain with improved floc forming ability and sludge sedimentation ability. In claim 1, Bacillus thuringiensis EnB2 KCTC 11394BP strain, characterized in that the strain has the rDNA sequence of SEQ ID NO: 1. A culture of Bacillus thuringiensis EnB2 KCTC 11394 of claim 1. Microbial agent for wastewater treatment, comprising the culture solution of claim 3. delete The method according to claim 4, The microbial agent is characterized in that it has a sedimentation improving ability.

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