JP3398760B2 - Water treatment method, water treatment agent and aerobic denitrifying bacteria - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a water treatment method, a water treatment agent, and denitrifying bacteria.

At present, the atmospheric concentration of nitrous oxide gas (N ₂ O), which has a strong greenhouse effect, is rapidly increasing. One of the main sources of this nitrous oxide gas is considered to be a wastewater treatment plant.

In recent years, attention has been paid to nitrogen in wastewater which causes eutrophication and pollution of rivers, lakes and marshes, coastal oceans, etc., and some local governments regulate the nitrogen concentration standard of wastewater by ordinance. Have begun.

The most effective means of removing nitrogen dissolved in water is biological denitrification. By the denitrification, nitric acid and ammonia nitrogen are converted into nitrogen gas (N ₂ ) and nitrous oxide gas, and released into the atmosphere.

However, the fact that such a nitrogen removal method has become widespread worldwide without the generation of N ₂ O being a problem is
It is a big problem for the global environment in the 21st century.

In the wastewater treatment, the treatment water is simply aerated (aerated). Even today, there are many such treatment plants, but if only aeration treatment is performed, BOD in treated water
Although the organic substances expressed by COD and COD are reduced, there is a problem that nitrogen and phosphorus cannot be removed.

In order to solve this problem, the state-of-the-art equipment employs a method of intermittent aeration for nitrogen removal and insoluble phosphate formation by addition of a coagulant for phosphorus removal.
The intermittent aeration method is a method of removing nitrogen by using denitrifying bacteria during non-aeration.

[0008]

However, as a result of studies by the present inventor, it was found that the intermittent aeration method produces N ₂ O or lowers the denitrification activity when the removal of dissolved oxygen is insufficient. It was

[0009] For the global environment, de窒産material is desirably N _2, N ₂ O should not be discharged. Also, due to the above-mentioned nitrogen concentration regulation, it is expected that the denitrification treatment of wastewater will expand rapidly on a global scale, but with consideration for denitrification products (N ₂ or N ₂ O), how efficiently It is important to denitrify.

The present invention protects the global environment by using a denitrification system that does not generate N ₂ O and has a high denitrification performance even under aerobic conditions that must be taken in general wastewater treatment. An object is to provide a water treatment method.

[0011]

According to the present invention, when treating water containing a nitrogen compound, the water and Pseudomonas suttu (Pseudomonas stu) are treated.
tzeri) -TR2FERM P-17713 and Ralstonia picty
ktti) -K50 FERM P-17712 and at least one denitrifying bacterium are mixed to decompose the nitrogen compound.

Further, the present invention, in treating water containing a nitrogen compound, said water, activated sludge, and Fusarium oxyspoum.
rum) -MT-811 FERM P-17714 to decompose the nitrogen compound.

Further, in the present invention, in treating water containing a nitrogen compound, the water, Pseudomonas stazzeri-ZoBell, and Fusarium oxysporum-MT-811 FERM P-17714 are mixed to obtain the nitrogen compound. The present invention relates to a water treatment method characterized by decomposing water.

The present inventor has studied various water treatment methods in order to obtain a denitrification system capable of efficiently decomposing nitrogen compounds in water.

Aeration (aerobic) treatment is necessary for cleaning wastewater contaminated with various organic substances.

However, denitrification by denitrifying bacteria generally prefers non-aerobic (anaerobic) conditions and is incompatible with the conditions for removing organic substances.

As a result of a study by the present inventor, when denitrifying bacteria are activated with insufficient oxygen removal, N ₂ O is often generated, which makes it difficult to remove both organic matter and nitrogen at the same time. I found out that there is.

Based on such knowledge, the present inventor has studied in detail the water treatment as the N ₂ O inhibiting denitrification system.

As a result, the inventor of the present invention isolated the ideal denitrifying bacteria for such denitrification system from the natural world, and arrived at the present invention. In the present invention, the denitrifying bacterium is used as a term indicating both denitrifying bacteria and denitrifying fungi (yeast is included in fungi).

The present inventor has completed the present invention by discovering that nitrogen compounds can be decomposed extremely efficiently and safely by utilizing such aerobic denitrifying bacteria.

The present invention is based on the excellent denitrification performance of at least one denitrifying bacterium of Pseudomonas stazzeri-TR2 FERM P-17713 and Ralstonia picti-K50 FERM P-17712.

These denitrifying bacteria of the present invention suppress the generation of N ₂ O and have a high denitrifying performance even under aerobic conditions generally used in wastewater treatment.

In the present invention, Fusarium oxysporum-MT-811 FERM P-17714 is used as activated sludge or Pseudomonas stazzeri-ZoBell.
It is based on the finding that it exhibits excellent denitrification performance when mixed with.

Fusarium oxysporum-MT-81
1 FERM P-17714, when mixed with activated sludge and Pseudomonas stazzeri-ZoBell,
Compared with the case of activated sludge alone, nitrogen compounds can be decomposed efficiently while suppressing the generation of N ₂ O.

In the water treatment method of the present invention, by using such aerobic denitrifying bacteria, the generation of N ₂ O is suppressed under aerobic conditions, and the load on the environment is suppressed, and the water is efficiently treated. Can decompose nitrogen compounds.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail based on the embodiments. The denitrifying bacterium of the present invention, Pseudomonas stazzeri-TR2 FERM
P-17713 and Ralstonia Picky-K50
FERM P-17712 can be isolated from nature.

Such denitrifying bacteria were prepared by applying a sample such as soil to the primary screening medium shown in Table 1 below.
After incubation for 1 to 3 days at 0 ° C., colonies whose surroundings are colored blue can be isolated for isolation.

[0028]

[Table 1]

The isolated denitrifying bacteria were subjected to MM shown in Table 2 below as a secondary screening according to the examples of the present specification.
Culture in liquid medium or MMYS liquid medium shown in Table 4,
By analyzing nitrogen gas in the gas phase over time, their aerobic denitrification capacity can be investigated. In addition, M
As the trace element solution A added to the M liquid medium or the like, those shown in Table 3 can be used.

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

Pseudomonas stazzeri of the present invention
TR2 has been deposited as FERM P-17713 at the Institute of Biotechnology, Institute of Biotechnology, February 3, 2000. This Pseudomonas Stazzeri-TR
2 FERM P-17713 was isolated from a paddy field, and as a microbiological property, it is a gram-negative bacillus, has a nitrate reducing ability, and grows well with succinic acid as a carbon source. It is a new strain belonging to the bacterium [Pseudomonas stutzeri]. The identification results are shown below.

(First stage of identification; from analysis result of NCIMB Japan) Location of sample: Soil culture type: Slope medium culture temperature: 30 ° C. Cell morphology: Bacillus (0.8 × 1.5-2 μm) Gram stain: -Spores: -Mobility: + Colony morphology: Round, smooth, low convex, glossy, pale yellow Growth temperature C: NT catalase: + Oxidase: + O / F test:-From these results, isolate TR2 Has motility and is positive for both catalase and oxidase.
It is presumed to be a bacterium of the eudomonas group.

(Observation of micrograph) FIG. 1 shows the isolate TR2.
The micrograph (magnification: 1500) of is shown.

(Second step of identification; from analysis result of NCIMB Japan) Nitrate reduction: + Indole production:-Glucose oxidation:-Arginine dihydrolase:-Urease:-Esculin hydrolysis:-Gelatin hydrolysis: -β-galactosidase :-Substrate assimilation ability Glucose: + L-arabinose: -D-mannose: -D-mannitol: -N-acetyl-D-glucosamine: -Maltose: + potassium gluconate: + n-capric acid: + adipic acid: -Dl-malic acid: + sodium citrate: + phenyl acetate:-From these physiological property test results, the isolate TR2 was identified as Ps.
It is found to be Eudomonas stutzeri.

(Partial DNA sequence of 16S RNA gene) BLASTN 2.0.10 (Altschul
Et al., 1997, Nucleic Acids Re
s. 25: 3389-3402), a partial DNA sequence of the 16S RNA gene of the isolated strain TR2 was extracted, and a highly homologous one was extracted from the database (Ge
nBank: 686,000 sequences;
1,409,831.702 total lettte
rs). Below, TR2 16SR
The analysis result of the homology of the partial DNA sequence of NA gene is shown. The partial DNA sequence of the 16S RNA gene of isolate TR2 is shown in SEQ ID NO: 1.

[0038]

[Chemical 1]

From the first step of identification, the second step of identification, microscopic observation and partial DNA sequence of 16S RNA gene,
It can be seen that the isolate TR2 belongs to Pseudomonas stazzeri. The Pseudomonas stazzeri-TR2 FERMP-17713 of the present invention is, as shown in the examples of the present invention, known Pseudomonas stazzeri-ZoBell (FEBS Letters 2).
77, 205-209, 1991, etc.), it can be seen that this is a new strain.

Ralstonia picky-K5 of the present invention
0 has been deposited as FERM P-17712 with the Institute of Biotechnology, Institute of Biotechnology, February 3, 2000. This Ralstonia Picky-K50 FE
As a microbiological property, RM P-17712 is a gram-negative bacillus, has a nitrate-reducing ability, grows well using succinic acid, methanol, and formic acid as carbon sources, and is taxonomically considered to be bacteria (Ralstonia picti. (Ralston
ia pickttii)). The identification results of this new strain are shown below.

(First step of identification; from analysis result of NCIMB Japan) Location of sample: Soil culture type: Slant cell morphology: Bacillus (0.5 × 1.5 to 2 μm) Gram stain:-Spores: NT motility : + Colony morphology: circular, wavy edge, low convex, surface irregularity, glossy, cream color Growth temperature C: NT catalase: + oxidase: + O / F test:-

(Second stage of identification, rapid identification test; NCIM
B Japan analysis results) Nitrate reduction: -Indole production: -Glucose oxidation: -Arginine dihydrolase: -Urease: -Esculin hydrolysis: -Gelatin hydrolysis: -β-galactosidase: -Substrate assimilation ability Glucose: + L-arabinose: -D-mannose: -D-mannitol: -N-acetyl-D-glucosamine: -maltose: -potassium gluconate: + n-capric acid: + adipic acid: -dl-malic acid: + citric acid Sodium: + Phenyl acetate:-Additional test Oxidative degradation of glucose: + Fluorescent dye production on _W King's B agar:-PHBA accumulation: +

(Observation of micrograph) FIG. 2 shows the isolate K50.
The micrograph (magnification: 1500) of is shown.

From these results, the isolate K50 is a gram-negative bacillus having motility, and is positive for both catalase and oxidase. From the knowledge that it is oxidatively degrading glucose, although it is weak, it is a bacterium of the Pseudomonas group. It is believed that there is. From the physiological property test, the isolate K50 was identified as Ralstonia pick.
ettiii and Pseudomonas putida are suggested, but no fluorescent dye production is observed in King's B agar, arginine dihydrolase negative, poly-β-
Since K50 strain shows positive accumulation of hydroxybutyric acid (PHBA), Ralstonia picktti
i is a more appropriate bacterial group.

Fusarium oxysporum-M of the present invention
T-811 is Heisei 1 as FERM P-17714
It has been deposited at the Institute of Biotechnology, Institute of Biotechnology, Institute of Industrial Science, dated February 3, 2012. This Fusarium Oxysporum-M
As a microbiological property, T-811 FERM P-17714 is mycelial, forms asexual spores, develops well on potato dextrose medium, and forms white spores on aerial mycelia. It is a strain belonging to the mold [Fusarium oxysporum].

This fungal strain itself has been isolated and reported as a lipoxygenase-producing bacterium (Sato, T., M.
atsuda, Y .; , Takashio, M .; , Sat
o, K. Beppu, T .; , And Arima,
K. : Agric. Biol. Chem. 40,935
-961 (1976)). Further, the inventor of the present invention has found that this fungal strain itself denitrifies and has already reported (Shoun, H., and Tanimot).
o, T. , Denitrification by f
ungus Fusarium oxysporum
and involvement of cytoch
rome P-450 in therespirat
ory nitrate reduction. J.
Biol. Chem. 266,11078-11082
(1991)).

The aerobic denitrifying bacterium according to the present invention effectively acts as a denitrifying bacterium even under aerobic conditions for removing organic matter, and the organic matter and nitrogen are removed from water containing both the organic matter and the nitrogen compound to be treated. Helps to remove compounds at the same time. In addition, when such aerobic denitrifying bacteria are used for water treatment, N is more aerobic than under conventional denitrifying systems.
_It works as a denitrification system that suppresses the generation of ₂ O and can suppress the generation of greenhouse gases.

Pseudomonas stazzeri of the present invention
TR2 FERM P-17713, even under aerobic conditions, without generating N ₂ O, an ideal aerobic denitrifying bacteria to produce a N _2.

Such aerobic denitrifying bacteria are treated with N ₂ during water treatment.
Since it does not generate O, it does not adversely affect the environment even under aerobic conditions for removing organic substances, works effectively as denitrifying bacteria, and serves to remove both organic substances and nitrogen from treated water at the same time.

Further, the Pseudomonas stutzeri-TR2 FERM P-17713 of the present invention utilizes the C1 compound such as methanol and formic acid as the sole carbon source and grows well. Since such denitrifying bacteria can proliferate using an inexpensive C1 compound as an energy source, maintenance, culturing, wastewater treatment, etc. become inexpensive.

The Fusarium oxysporum-MT-811 FERM P-17714 according to the present invention belongs to a fungus (mold) and has a mycelial form, so that it can be easily separated from the treated water. Further, even under aerobic conditions, the denitrifying fungus effectively acts as a denitrifying fungus while suppressing the generation of N ₂ O, and serves to remove both organic matter and nitrogen from treated water at the same time.

The aerobic denitrifying bacterium according to the present invention is a general water treatment (general wastewater, agricultural / livestock wastewater, industrial wastewater treatment, river / groundwater treatment, etc.) as long as it treats water containing nitrogen compounds. Water purification etc.).

In the present invention, the nitrogen compound is not particularly limited. The aerobic denitrifying bacterium of the present invention or the aerobic denitrifying bacterium of the present invention can be used for the treatment of various nitrogen compounds. Examples of the nitrogen compound include nitrogen oxides such as nitric acid and nitrous acid. The method and aerobic denitrifying bacterium of the present invention are suitable for treating water containing these nitrogen compounds.

In the present invention, the water to be treated and Pseudomonas stazzeri-TR2 FERM P-1771 are used.
3, Fusarium oxysporum-MT-811 FE
RMP-17714 and Ralstonia Picky-K
50 FERM P-17712 and at least one aerobic denitrifying bacterium selected from the group consisting of
By mixing the activated sludge with this water, the nitrogen compounds contained in the water can be decomposed.

In such a water treatment method, denitrification occurs even under aerobic conditions, and the generation of nitrous oxide gas can be significantly suppressed.

The activated sludge is not particularly limited as long as the generation of nitrous oxide gas can be suppressed.
For example, ordinary activated sludge for denitrification and activated sludge for treating organic substances can be used. If activated sludge for ordinary denitrification is used, denitrification can be efficiently performed in an anaerobic state. Further, if activated sludge for treating organic matter is used, denitrification in aerobic water treatment can be promoted.

Further, in the present invention, by mixing water containing a nitrogen compound, the aerobic denitrifying bacterium of the present invention, and the anaerobic denitrifying bacterium, while significantly suppressing the generation of nitrous oxide gas, Nitrogen compounds in water can be decomposed efficiently.

As such an anaerobic denitrifying bacterium, Pseudomonas stazzeri-ZoBell, which is known as a known anaerobic denitrifying bacterium, can be used.

Further, in the present invention, the aerobic denitrifying bacterium of the present invention is contained in a carrier by immobilizing it on a suitable carrier or the like, whereby a water treatment agent for suppressing the generation of nitrous oxide gas can be obtained. it can.

The aerobic denitrifying bacterium of the present invention can promote the growth thereof by such a carrier. Further, the aerobic denitrifying bacterium of the present invention can be easily separated and recovered from the treated water after denitrification by the carrier. As the carrier, a porous body or the like can be used.

According to the invention, N ₂ O even under aerobic conditions.
Denitrifying bacterium that does not generate N ₂ O even under aerobic conditions
Denitrifying bacterium that significantly suppresses the generation of denitrification, and a complex culture aerobic denitrification system that uses a denitrifying fungus that exhibits efficient denitrification performance by mixing with activated sludge and anaerobic denitrifying bacteria,
A water treatment method that suppresses the generation of N ₂ O and reduces the load on the environment can be provided.

Further, according to the present invention, a water treatment agent can be provided by using these denitrifying bacteria as they are, or by immobilizing these denitrifying bacteria on an appropriate carrier, so that they can be applied at the water treatment site. Becomes

The water treatment method of the present invention can be used as a continuous water treatment device by electrically and mechanically controlling and automating it by an appropriate means. FIG. 3 is a typical flow chart of such a water treatment device.

The continuous water treatment device 1 comprises a reactor 2 and an untreated liquid.
Container 3, processing liquid container 4, oxygen and argon flow controller
5, 6, pH adjusting liquid container 7, condenser 8, gas sampling tube
9, O ₂ Converter 10, pH converter 11 and tea
A printer recorder 12 is provided.

In the reactor 2, an untreated liquid (fresh medium, etc.) 1
3 is sequentially supplied from the untreated liquid container 3 via the pump 14, and denitrification by the denitrifying bacteria is performed in the reactor 2.

The amount of oxygen and argon in the reactor 2 is O.
It is monitored by the chart recorder 12 by the ₂ converter 10 and is controlled by the oxygen and argon flow controllers 5, 6 respectively.

The pH in the reactor 2 is controlled by the pH converter 11
Is monitored by the chart recorder 12 and adjusted by the pH adjusting liquid 15 supplied from the pH adjusting liquid container 7.

Nitrogen, which is a denitrification product in the reactor 2, is condensed in the condenser 8 and sent to the analyzer through the gas sampling pipe 9.

The treatment liquid 16 treated with denitrifying bacteria is
It is sequentially discharged into the processing liquid container 4 via the pump 17, and the inside of the reactor 2 is kept in a steady state.

[0070]

The present invention will be described in more detail based on experimental examples with reference to the drawings. Experimental Example 1 In a flask culture, the denitrification process by an aerobic denitrifying bacterium of one example of the present invention was compared with a known denitrifying bacterium.

As the aerobic denitrifying bacterium of this example, Pseudomonas stutzeri-TR2 FERM P-177 is used.
13 (hereinafter referred to as "TR2 bacterial strain") was used.
Known denitrifying bacteria include Thiosphera pantotropha (Thiosphere) known as aerobic denitrifying bacteria.
a pantotroph) [hereinafter referred to as "TP bacterium". In addition, the scientific name of this bacterium has been changed, and it is Paracoccus.
However, since this scientific name is the same as another bacterium known as a denitrifying bacterium which has not been aerobic, it is referred to as “TP bacterium” in the present specification. ], And Pseudomonas stazzeri-ZoBell (Ameri), well known as a known anaerobic denitrifying bacterium.
can Type Culture Collecti
stored as the registration number ATCC 14405. Hereinafter referred to as "PS bacterial strain". This bacterium is named Pseudomonas perfecto.
It has been preserved in marina, but now the taxonomic name of this bacterium has changed and Pseudomonas stu
It is tzeri. ) Was used.

These denitrifying bacteria were pre-cultured under denitrifying conditions (nitrogen source: sodium nitrate, 30 ° C., 120 rpm),
Then, the cells were collected and washed (0.9% NaCl).

These denitrifying bacteria were inoculated into 100 mL (500 mL Erlenmeyer flask) of MM liquid medium shown in Table 2, and this was subjected to main culture (30 ° C., 120 rpm) to obtain N ₂ and N in the gas phase. ₂ O and O ₂ were analyzed by GC. The N ₂ isotope ratio was analyzed by GC / MS.

FIG. 4 is a graph showing the denitrification process of the TR2 bacterial strain of the present invention. FIG. 5 is a graph showing the denitrification process of TP bacteria known as aerobic denitrifying bacteria. Figure 6
FIG. 4 is a graph showing the denitrification process of a PS bacterial strain famous as a known anaerobic denitrifying bacterium.

As shown in FIG. 4, in the course of pure culture of the TR2 bacterial strain, denitrification (generation of N ₂ from sodium nitrate) started before oxygen (O ₂ ) decreased. With other bacteria such as those shown in FIGS. 5 and 6, denitrification did not begin until oxygen was reduced. In addition, N ₂ O was also generated in the bacterium shown in FIG.

The TR2 bacterial strain of the present invention is under more aerobic conditions than known famous anaerobic denitrifying bacteria (PS bacterial strains) or known aerobic denitrifying bacteria (TP bacteria). So N
It was found that the activity of forming ₂ is high and that N ₂ O is not generated.

Experimental Example 2 An example of an aerobic denitrifying fungus according to the present invention, a denitrifying process with Fusarium oxysporum, and this aerobic denitrifying fungus were mixed with floating sludge (active sludge) in a water treatment plant. The effect of addition on the denitrification activity of activated sludge was confirmed.

The aerobic denitrifying fungus of this example is Fusarium oxysporum-MT-811FERM P-17.
714 (hereinafter referred to as "MT-811 fungal strain") was used. As the floating sludge in this example, activated sludge (floating sludge) collected from a wastewater treatment plant was used.

In the same manner as in Experimental Example 1, denitrifying fungus (MT-
811 fungus strain) was used to test the denitrification process. Na
In this experimental example, the medium container was opened and new
Do N ₂ O was measured.

FIG. 7 is a graph showing the denitrification process by the MT-811 fungal strain of the present invention. FIG. 8 is a graph showing a denitrification process using activated sludge. FIG. 9 is a graph showing the denitrification process using a mixture of activated sludge and the MT-811 fungal strain of the present invention. FIG. 10 is a graph obtained by re-plotting FIGS. 7 to 9 and is a graph showing a decrease in nitrate ion. FIG. 11 is a graph obtained by plotting FIGS. 7 to 9 again and showing the generation of N ₂ O.

As shown in FIG. 7, MT-811 of the present invention.
The fungal strain was superior to the activated sludge alone shown in FIG. 8 in the ability to reduce nitrate ions, and the N ₂ O production was also significantly less. Further, as shown in FIGS. 9 to 11, the MT-
By using the mixture of 811 fungal strain and activated sludge (composite system), the decrease of nitrate ion was almost complete and the decrease of N ₂ O production was also complete over time.

As described above, as another device of the present invention, the treated water is treated by the combined culture of the MT-811 fungal strain (mold) discovered by us and the activated sludge (floating sludge) collected from the wastewater treatment site. Nitrogen (nitric acid) could be removed efficiently by suppressing the generation of N ₂ O from.

From this example, it was also found that the aerobic denitrifying bacterium of the present invention can be applied to a water treatment site by immobilizing it on a carrier. Furthermore, MT-811 of the present invention
The fungal strain had a hyphal form and was easy to separate from the treated water.

Experimental Example 3 A denitrification process by a mixed system of the MT-811 fungal strain of the present invention and a known anaerobic denitrifying bacterium was studied.

In this example, as known anaerobic denitrifying bacteria,
The same PS bacterial strain as in Experimental Example 1 was used.

The treatment was carried out in MM-glycerol medium or MM.
-The same conditions as in Experimental Example 2 were used except that methanol and formate medium were used. The composition of the MM-glycerol medium is shown in Table 5. The trace element solution B shown in Table 6 was added to this MM-glycerol medium. The MM-methanol and formate medium used was the same as the MM-glycerol medium except that 5 mmol of methanol and formic acid were added instead of glycerol in Table 5.

[0087]

[Table 5]

[0088]

[Table 6]

FIG. 12 shows known PS bacterial strains and M of the present invention.
FIG. 3 is a graph showing the denitrification process of T-811 fungal strains tested alone and in a mixed system in MM-glycerol medium. FIG. 13 shows the known P
FIG. 3 is a graph showing N ₂ production and O ₂ reduction, when the S bacterial strain and the MT-811 fungal strain of the present invention were tested alone and in a mixed system in MM-glycerol medium. FIG. 14 shows known PS bacterial strains and MT of the present invention.
Respectively For single -811 fungal strain, and a case of mixed system, although tested at MM- methanol and formate salt medium is a graph showing the N ₂ and N ₂ O produced.

As shown in FIG. 12, when MM-glycerol was used as the medium, the MT-811 fungal strain of the present invention produced N ₂ and N ₂ O from nitrate ion as compared with the known PS bacterial strain. Despite the markedly low potency, the mixed system in which the MT-811 fungal strain of the present invention and the known PS bacterial strain were mixed exhibited significantly higher N ₂ production ability than the known PS bacterial strain alone. And the ability to generate N ₂ O was almost completely suppressed.

As shown in FIG. 13, MT of the present invention is used.
In a mixed system of -811 fungal strain and known PS bacterial strain,
The decrease of ₂ was remarkable, and the N ₂ forming ability was extremely high.

As shown in FIG. 14, when MM-methanol and formate were used in the medium, MT-811 of the present invention was obtained.
The mixed system of fungal strains and known PS bacterial strains, N ₂ generation ability is significantly higher than known PS bacterial strains alone, N ₂
The O generation ability was remarkably suppressed.

Thus, the aerobic denitrifying fungus (M
It was found that nitrogen (nitrate, etc.) can be removed efficiently by complex culture of T-811 fungal strain) and a known anaerobic denitrifying bacterium (PS bacterial strain). Further, since the aerobic denitrifying fungus (MT-811 fungal strain) of the present invention has a mycelial form, it was easy to separate it from the treated water.

Experimental Example 4 With respect to the TR2 bacterial strain of the present invention, the denitrification process was studied using either formic acid or methanol as the C1 compound as the sole carbon source.

The treatment using formic acid as a carbon source was performed in the same manner as in Experimental Example 1 except that the medium having the composition shown in Table 7 below was used. Further, the treatment using methanol as a carbon source was carried out in the medium shown in Table 7,
The procedure was the same as for formic acid except that a medium containing equimolar methanol was used instead of formic acid. Note that C
/ N = 6, C / N = 12, C / N = 36 shows that the molar ratio of formic acid or methanol and nitric acid is 6,12,36. The results are shown in FIGS.

[0096]

[Table 7]

FIG. 15 is a graph showing the formation of N ₂ and N ₂ O of TR2 using formic acid. FIG. 16 is a graph showing O ₂ reduction of TR2 using formic acid. FIG. 17 is a graph showing N ₂ and N ₂ O production of TR2 using methanol. FIG. 18 shows O of TR2 using methanol.
₂ is a graph showing a decrease of ₂ .

As shown in FIG. 15 and FIG. 16, the TR2 bacterial strain of the present invention did not produce N ₂ O under aerobic conditions even if formic acid was the only carbon source, and C / N = 32. It was found that, except for the above, good N ₂ production was shown, and the denitrification performance was excellent.

As shown in FIG. 17 and FIG. 18, the TR2 bacterial strain of the present invention has methanol as the sole carbon source.
Without producing N ₂ O under aerobic conditions, good N ₂
It was found that the product showed production and was excellent in denitrification performance.

Experimental Example 5 Denitrifying bacteria were continuously cultured in a steady state to study the denitrifying process of the denitrifying bacteria.

In this treatment, the TR2 bacterial strain of the present invention and Ralstonia picti-K50 FERM P-17712 (hereinafter referred to as "K5
0 bacterial strain ". ), As a known denitrifying bacterium,
TP and PS bacterial strains were used.

In the denitrification process of these denitrifying bacteria, 2 mL / mL of the trace element solution shown in Table 3 was added to the medium having the basic composition shown in Table 8.
Examination was performed using a medium prepared by adding L at a ratio of L and a continuous culture device controlled electrically and mechanically as shown in FIG.

[0103]

[Table 8]

Tables 9 to 12 show the denitrification states of the TR2 bacterial strain of the present invention, the K50 bacterial strain of the present invention, the known TP bacterium and the known PS bacterial strain, respectively. These denitrifying bacteria maintained a steady state under the conditions of different stirring rates and oxygen supply rates shown in Tables 9 to 12, respectively.

[0105]

[Table 9]

[0106]

[Table 10]

[0107]

[Table 11]

[0108]

[Table 12]

As shown in Table 9, the TR2 bacterial strain of the present invention has an optical density (OD ₅₄₀ ) in the anoxic state or a low dissolved oxygen concentration (DO) as compared with the TP bacterium shown in Table 11.
High and grow well to produce N _2, while producing significantly less N ₂ O.

Further, the TR2 bacterial strain of the present invention proliferates favorably and produces N ₂ without increasing the amount of N ₂ O produced, even when the dissolved oxygen concentration is high, as compared with the TP bacterium.

Further, the TR2 bacterial strains of the present invention are listed in Table 12.
Compared with the PS bacterial strain shown in Fig. ₃ , it produces N ₂ favorably at a low dissolved oxygen concentration, the production amount of N ₂ O is extremely small, and it grows well even at a high dissolved oxygen concentration, and the production amount of N ₂ O is remarkable. Few.

As shown in Table 9, the K50 bacterial strain of the present invention, like the TR2 bacterial strain, grows better at a lower dissolved oxygen concentration as compared to the TP bacterial strain, and suppresses N ₂ O production to reduce N ₂ production. It does not increase the amount of N ₂ O produced even if it is produced and has a high dissolved oxygen concentration.

Further, the K50 bacterial strain of the present invention, like the TR2 bacterial strain, has an N concentration lower than that of the PS bacterial strain at a lower dissolved oxygen concentration.
₂ O production is suppressed, N ₂ is produced, and it proliferates remarkably even at a high dissolved oxygen concentration, and N ₂ O production is suppressed to produce N ₂ .

[0114]

EFFECTS OF THE INVENTION According to the water treatment method, water treatment agent and water treatment apparatus of the present invention, the use of a predetermined aerobic denitrifying bacterium suppresses the generation of N ₂ O under aerobic conditions. The nitrogen compound in water can be efficiently decomposed while suppressing the load on the environment.

[0115]

[Sequence list] SEQ ID NO: 1 Sequence length: 860 Sequence type: Nucleic acid origin   Organism name: Pseudomonas                                                     stutzeri)   Strain name: TR2 (FERM P-17713) Array    gtcaattcat ttgagtttta accttgcggc cgtactcccc aggcggtcga    cttaatgcgt tacgtgcgcc actaagatct caaggatccc aacggctagt    cgacatcgtt tacggcgtgg actaccaggg tatctaatcc tgtttgctcc    ccacgctttc gcacctcagt gtcagtatta gcccaggtgg tcgccttcgc    cactggtgtt ccttcctata tctacgcatt tcaccgctac acaggaaatt    ccaccaccct ctgccatact ctagcttgcc agttttggat gcagttccca    ggttgagccc ggggctttca cattcaactt aacaaaccac ctacgcgcgc    tttacgccca gtaattccga ttaacgcttg cacccttcgt attaccgcgg    ctgctggcac gaagttagcc ggtgcttatt ctgtcggtaa cgtcaaaaca    ctaacgtatt aggttaatgc ccttcctccc aacttaaagt gctttacaat    ccgaagacct tcttcacaca cgcggcatgg ctggatcagg ctttcgccca    ttgtccaata ttccccactg ctgcctcccg tagagtctgg accgtgtctc    agttccagtg tgacctcacc aactagctaa tccgacctag actcatctga    tagcgcaagg cccgaagtcc cctgctttct cccgtaggac gtatgcggta    ttagcgttcc tttcgaaacg ttgtccccca ctatcaggca gattcctagg    cattactcac ccgtccgccg ctgaatcaga gagcaagctc tcttcatccg    ctcgacttgc atgtgttagg cctgccgcca gcgttcaatc tgagccagga    tcaaactcta

[Brief description of drawings]

FIG. 1 is a drawing-substitute photograph of the TR2 bacterial strain of the present invention.

FIG. 2 is a drawing-substitute photograph of the K50 bacterial strain of the present invention.

FIG. 3 is a diagram showing a water treatment device according to an example of the present invention.

FIG. 4 is a graph showing the denitrification process of the TR2 bacterial strain of the present invention.

FIG. 5 is a graph showing the denitrification process of known TP bacteria.

FIG. 6 is a graph showing the denitrification process of other known PS bacterial strains.

FIG. 7 is a graph showing the denitrification process of the MT-811 fungal strain of the present invention.

FIG. 8 is a graph showing a denitrification process using only activated sludge.

FIG. 9 is a graph showing a denitrification process by mixed culture of activated sludge and MT-811 fungal strain.

FIG. 10 is a graph showing a decrease in nitrate ion by plotting FIGS. 5 and 6 again.

FIG. 11 is a graph showing the production of N ₂ O by plotting FIGS. 5 and 6 again.

FIG. 12 Known PS bacterial strains and MT-811 of the present invention.
FIG. 3 is a graph showing the denitrification process of the fungal strains tested alone and in a mixed system in MM-glycerol medium.

FIG. 13: Known PS bacterial strains and MT-811 of the present invention
With each of the fungal strains alone and with the mixed system
Was tested in MM-glycerol medium, but N ₂ Raw
Naru and O₂ It is a graph which shows decrease.

FIG. 14 Known PS bacterial strains and MT-811 of the present invention.
And in each case a single fungal strain, and a case of mixed system, although tested at MM- methanol and formate salt medium is a graph showing the N ₂ and N ₂ O produced.

FIG. 15 is a graph showing N ₂ and N ₂ O production of TR2 using formic acid.

FIG. 16 is a graph showing O ₂ reduction of TR2 using formic acid.

FIG. 17: N ₂ and N _{2 of} TR2 using methanol
It is a graph which shows O generation.

FIG. 18 is a graph showing O ₂ reduction of TR2 using methanol.

[Explanation of symbols]

1 Continuous Water Treatment Device 2 Reactor 3 Untreated Liquid Container 4 Treated Liquid Container 5 Oxygen Flow Controller 6 Argon Flow Controller 7 pH Adjustment Liquid Container 8 Condenser 9 Gas Sampling Pipe 10 O ₂ Converter 11 pH Converter 12 Chart Recorder 13 Untreated liquid (fresh medium, etc.) 14,17 Pump 15 pH adjustment liquid 16 Treatment liquid

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI C12N 1/20 ZNA C12N 1/20 ZNAA // (C12N 1/14 1/14 C12R 1:77) C12R 1:77 (C12N 1 / 20 C12N 1 / 20A C12R 1:38) C12R 1:38 (56) Reference JP 6-121998 (JP, A) JP 6-327467 (JP, A) JP 11-253992 ( JP, A) JP-A 1-218698 (JP, A) Japanese Patent Publication No. 56-52639 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 3/28-3/34 C12N 1/00-7/08

Claims (8)

(57) [Claims] 1. When treating water containing a nitrogen compound, the water and Pseudomonas stutzeri-TR2 F are treated.
A method for treating water, comprising mixing ERM P-17713 and Ralstonia picti-K50 FERM P-17712 with at least one denitrifying bacterium to decompose the nitrogen compound. 2. The water treatment method according to claim 1, wherein the denitrifying bacterium is Pseudomonas stazzeri-TR2 FERM P-17713. 3. When treating water containing a nitrogen compound, the water, activated sludge, and Fusarium oxysporum-
Mix with MT-811 FERM P-17714,
A method for treating water, which comprises decomposing the nitrogen compound. 4. When treating water containing a nitrogen compound, the water and Pseudomonas stutzeri-ZoBel are treated.
1 and Fusarium oxysporum-MT-811 F
A method for treating water, which comprises mixing with ERM P-17714 to decompose the nitrogen compound. 5. A water treatment agent for decomposing nitrogen compounds in water, wherein the water treatment agent is Pseudomonas stazzeri-TR.
2. A water treatment agent containing at least one denitrifying bacterium of FERM P-17713 and Ralstonia picti-K50 FERM P-17712. 6. A water treatment agent for decomposing nitrogen compounds in water, wherein the water treatment agent is Pseudomonas stazzeri-Zo.
Bell and Fusarium oxysporum-MT-81
1 FERM P-17714 and water treatment agent characterized by the above-mentioned. 7. A denitrifying bacterium that decomposes nitrogen compounds, which is Pseudomonas stutzeri-TR2 FERM.
A denitrifying bacterium characterized by being represented by P-17713. 8. A denitrifying bacterium that decomposes nitrogen compounds, which is Ralstonia picti-K50 FERM P.
A denitrifying bacterium characterized by being represented by -17712.