JPH01135595A - Removing method for dimethylformamide - Google Patents

Abstract

PURPOSE:To decompose and remove dimethylformamide by bringing a dimethylformamide-containing liquid into contact with strains of a specific bacterium. CONSTITUTION:Strains of a specific microorganism, such as PSEUDOMONAS AMINOVORANS, belonging to the genus PSEUDOMONAS are cultured in a culture medium in which a dimethylformamide-containing liquid coexists with nutrients such as a carbon source, a nitrogen source and an inorganic component. The above culture is aerobically performed at a temperature of 5-35 deg.C and at a pH of 6-8. Accordingly, the dimethylformamide is decomposed and removed, whereby the waste liquid can be changed into a harmless liquid.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a method for decomposing and removing dimethylformamide from a liquid containing dimethylformamide, and more particularly relates to a method for decomposing and removing dimethylformamide from a liquid containing dimethylformamide. It relates to a method of decomposing and removing formamide using bacteria.

[Prior art and problems to be solved by the invention] Dimethylformamide is hydrophilic, stable against heat, highly polar, and highly soluble in many organic and inorganic compounds. It is a compound whose usage has been increasing significantly in recent years because it is a powerful solvent and an excellent solvent.

Its main uses are as a solvent for the production of synthetic fibers and synthetic leather, as a solvent for acrylic synthetic resins and vinyl synthetic resins, as a solvent for pharmaceutical raw materials, and for paints and pigments. These effluents containing dimethylformamide after being used for these purposes can be used for aquatic animals such as fish. Since it is harmful to microorganisms and algae, it must be detoxified before being released for environmental hygiene reasons. However, dimethylformamide is generally highly toxic to microorganisms, and therefore cannot be rendered harmless by conventional activated sludge treatment.

On the other hand, methods for decomposing and removing dimethylformamide in wastewater containing dimethylformamide include, for example,
There is a method described in Japanese Patent Publication No. 54-1792. This method uses enzymes in the cells of microorganisms belonging to the genus Micrococcus, but its processing capacity is insufficient for practical use.

If we can find a microorganism that can efficiently assimilate or decompose dimethylformamide, which is stable and difficult to decompose, it will be possible to use this microorganism to efficiently detoxify wastewater containing dimethylformamide. Become.

[Means and effects for solving the problem] The present inventors,
As a result of extensive searches in the natural world, we discovered microorganisms that can actively assimilate or strongly decompose dimethylformamide, and completed the present invention using this microorganism.

That is, the present invention involves contacting a liquid containing dimethylformamide with the cells of a bacterium belonging to the genus Pseudomonas that can assimilate and decompose dimethylformamide, and/or a bacterial cell-treated product of the bacterium. A method for removing dimethylformamide, which is characterized by decomposing and removing dimethylformamide.

The bacteria used in the present invention belong to the genus Pseudomonas,
Assimilates dimethylformamide efficiently.

There are no particular limitations as long as the strain has the ability to decompose.

Representative examples of these strains include Pseudomonas aminovorans.
rans) DM-81 (Feikoken Bibori No. 9498).

This bacterial strain was isolated from soil by the present inventors.

The mycological properties of this strain are shown below.

1. At 30°C for both the liquid broth medium and agar agar medium.
The cells were cultured for 1 day.

■ Straight rod Width 0.9-1.24 Length 1.5-4-
■ Can be clustered, unicellular or bicellular.

■ Has motility. It has polar flagella.

■ Presence or absence of spores Not produced.

■ Durham staining Negative.

■ Anti-acidity Negative.

■ Extracellular adhesive is not produced.

2. Growth status in each of the following media (culture at 30°C for 3 days unless otherwise specified) ■ Morphology and properties of broth agar colony: External shape - round, size 12-3fflI+.

Ridges - hemispherical, structure - homogeneous, surface - smooth.

Edge = gold edge, smooth, 1 color - white or yellowish white, transparency -
Opaque, hardness - buttery.

■ Monomethylamine-containing agar plates Same as in broth agar plates.

■ Broth agar slant medium Grows vigorously and uniformly along the inoculation line.

Colony morphology and properties: Ridges - Moderate 1 Surface - Smooth 9 Edges - Smooth.

Color - white or yellow-white, transparency - opaque.

Hardness - buttery.

■ Monomethylamine-containing agar slants Same as in broth agar slants.

■ Broth liquid medium Grows all over. There is precipitation. Does not form bacterial rings.

■ Peptone water liquid medium Grows weakly throughout. There is precipitation. Does not form bacterial rings.

■ Monomethylamine-containing liquid medium Grows all over. There is precipitation. Does not form bacterial rings.

■ Meat juice agar puncture culture Grows uniformly in the shape of small papillae. On the surface of the medium, the diameter is 2-4
Grows in a circular shape.

■ Monomethylamine-containing agar puncture culture Grows uniformly in the shape of small papillae. On the surface of the medium, it grows in a circular shape with a diameter of about 2 to 4 inches.

[Phase] Gravy gelatin high-rise culture Culture at 20°C for 10 days.

Bacterial growth is observed, but gelatin is not liquefied.

■ Ridmus milk Cultured at 30″C for 4 weeks.

Although bacterial growth is observed, alkali is not produced. Grows vigorously.

3. Physiological properties ■ Reduction of nitrate Reducing nitrate to nitrite.

■ MR test Negative.

■ VP test Negative.

■ Indole production Negative.

■ Generation of hydrogen sulfide Negative.

■ Starch hydrolysis Negative.

■ Use of citric acid (combined Koser medium and Christensen medium) Do not use.

■ Use of nitrogen sources Ammonium salts, nitrates and peptone are used as nitrogen sources.

■ Pigment generation　　　　　　　　No generation.

[Phase] Urease positive.

■ Catalase positive.

@Generation of ammonia　　　　　　　　　　Generate.

@ Growth range: Grows in the pi 6-8 range. The pH range is preferably from 6.5 to 7.5.

Grows at a temperature of 5-35°C. 10-32°C is preferred.

■　Attitude towards oxygen　　　Aerobic.

■ Oxidase Negative.

■ O-F test (HughLe
Ifson method) decomposes sugar oxidatively, but not fermentatively,
(Left below) ■ Assimilation of sugars and production of acids and gases [Phase] Assimilation of carbon sources other than sugars [Phase] Salt tolerance Does not grow in 3wtχNaC1-containing medium.

[Phase] Vitamin requirement Absolutely does not require vitamins.

0 Denitrification reaction Negative.

@CC (guanine + cytosine) content 63.2n+olχ ■ Main bacterial fatty acid composition Monounsaturated fatty acid C11lil [phase] Main hydroxy acid 3-hydroxy acid CI! +.

@ Quinone type Ubiquinone Q1゜[phase]
Separation source soil.

Among its mycological properties, this strain has polar flagella, forms white or yellow-white colonies, is a Durham-negative monomethylamine-assimilating bacterium, and has a GC content of 63.2 m
olχ, monounsaturated fatty acid Cl111 is the main bacterial fatty acid composition, 3-hydroxy acid CItIO is the main hydroxy acid, and the quinone type is ubiquinone QI.
Since it is a G, the classification by Urakami and Komagata [“J,
Gen. Microbiol, 32, 317-341.
(1986)), Pseudomonas aminovorans Pse belongs to group 1 monomethylamine-assimilating bacteria.
The strain was identified as belonging to Udomonas a+m1novorans.

In the present invention, experimental methods for investigating mycological properties are described in Bergey's Manual of Systematic Bacteriology.
of Systematic Bacteriolo
gy” Volume 1.

Editors: Cleave and Holt
t): Williams and Wilkins
Liams & Wilkins), (1984)
) J, Institute of Medical Science Alumni Kinsen “Bacteriology Practice Summary J
(1958) and “Classification and Identification of Microorganisms J” (1975) edited by Takeharu Haseyo.

A monomethylamine-containing agar plate medium and a monomethylamine-containing agar slant medium were prepared as follows. That is, (NHa>tsOa 3g, KHzPOnl
, 4g1NatHPO* 2.18. MgSO4・7
Hz80.2g.

CaC1,°2Hz030mgt PeC,H,Ot・
XHzo 30mg, MnC1g'4Hz05g,
Zn5On'7Hz05mg, CLISO4°5Hz
O0.5mg.

Yeast extract 0.2g and monomethylamine hydrochloride 5g
After dissolving in pure water 11 and adjusting the pH to 7.1,
Furthermore, 15 g/f of agar was added and dissolved by heating.
It was sterilized at 1 kg/ctiG for 20 minutes.

As the monomethylamine-containing liquid medium, a medium with the same composition as the monomethylamine-containing agar plate medium and the monomethylamine-containing agar slant medium without the addition of agar was used.

Further, a dimethylformamide-containing agar plate medium and a dimethylformamide-containing agar slant medium were prepared as follows. That is, (NHa) tsOa 3 g.

, KHzPOa 1.4g, NaJPOa 2.1
g+ MgSO4'7Hz00.2g.

CaC1z°2H2030mg, FeCJ50v'X
Hz030mg, MnC1g・4Hz05g, Zn
5O,°7HzO5nag, CuSO4°sHgo
0.5ff1g.

Dissolve 0.2 g of yeast extract and 1 i of pure water, pt+
was adjusted to 7.1. To this, 15 g/f agar was further added and dissolved by heating, followed by 5 g dimethylformamide.
/l and sterilized at 1 kg/cdG for 20 minutes.

As the dimethylformamide-containing liquid medium, a medium without agar was used in the composition of the dimethylformamide-containing agar plate medium and dimethylformamide-containing agar slant medium described above.

Liquid containing dimethylformamide (hereinafter referred to as the liquid to be treated)
In order to render harmless dimethylformamide (sometimes referred to as There is a method of culturing this bacterium.

That is, the nutritional components added to the liquid to be treated are not particularly limited as long as they can be assimilated by the bacteria used, and include carbon sources, nitrogen sources, inorganic components, and other components.

As a carbon source, dimethylformamide alone in the liquid to be treated may be used, but other carbon sources that can be assimilated by the bacteria used, such as D-xylose.

Sugars such as D-glucose, D-fructose, D-galactose, maltose and sucrose, sugar alcohols such as D-sorbitol and D-mannitol, organic acids such as acetic acid, alcohols such as ethanol, and monomethylamine and dimethyl Amines and alkylamines such as trimethylamine can also be used in combination.

As nitrogen sources, use is made of inorganic nitrogen compounds, such as, for example, ammonium salts and nitrates, and/or organic nitrogen-containing substances, such as, for example, alkylamines, corn steep liquor, casein, peptone and meat extracts.

Note that, since dimethylformamide is a nitrogen compound, the present bacteria can sufficiently grow and proliferate to assimilate and decompose dimethylformamide without adding any other nitrogen source.

In addition, examples of inorganic components include calcium salts, magnesium salts, potassium salts, sodium salts, phosphates,
Manganese salts, zinc salts, iron salts, copper salts, molybdenum salts, cobalt salts, boromine compounds, iodine compounds, and the like are used.

Furthermore, when using a bacterial strain that requires nutritional substances such as vitamins, add the nutritional substances required by the strain.

The concentration of dimethylformamide in the liquid to be treated may be such that the bacteria used can assimilate and decompose it.
Although there is no particular restriction, it is usually preferably 3 vit% or less, particularly preferably 2 wt% or less.

The culture conditions may be any conditions that allow the bacteria used to grow and proliferate;
, preferably 10-32°C, pH 6-8,
Preferably, it is 6.5 to 7.5.

Culture is carried out aerobically under these conditions.

In addition, the dissolved oxygen concentration of the culture solution is low enough for this bacterium to grow.

The dissolved oxygen concentration should be such that it can proliferate (there is no particular limit, but usually about 0.5 to 20 ppm is preferable. To achieve such a dissolved oxygen concentration, adjust the amount of aeration gas or , stirring, using oxygen gas or a mixed gas of oxygen and air as aeration gas, and increasing the pressure inside the culture tank.

Although the growth and proliferation of this bacterium will be relatively poor and the efficiency of dimethylformamide removal and decomposition will be relatively reduced, this does not preclude culturing under these conditions.

Furthermore, the culture method may be batch culture, continuous culture, or semi-continuous culture.

When an ammonium salt or an alkylamine salt is used as a nitrogen source, ammonia and amine are each consumed for bacterial cell production during the culture period, resulting in a decrease in the pH of the culture solution. In this case, in order to maintain the pH of the culture solution at a predetermined value, ammonia, amines, alkalis such as caustic potash and caustic soda are added, and it is most preferable to add ammonia.

In addition to the method of making the liquid to be treated harmless by culturing the bacteria using the liquid to be treated as a medium as described above,
Pre-cultured cells of this bacterium and processed materials of this bacterium - for example, culture solution containing cells of this bacterium, crushed cells of this bacterium, and cells of this bacterium are prepared using synthetic resin, etc. Immobilized microbial cells (hereinafter sometimes referred to as "microbial cells") can also be brought into contact with the liquid to be treated.

For example, (a) adding microbial cells to the liquid to be treated; (c) bringing the liquid to be treated into contact with activated sludge mixed with the bacterial cells, culture solution, and crushed bacterial cells; and (c) There are methods such as passing the liquid to be treated through a column filled with immobilized bacterial cells.

In addition, for wastewater containing dimethylformamide,
Since the wastewater often contains other substances, it is possible and preferable to use a bacterial strain that can decompose other substances together with the present bacteria in treating such wastewater.

After the treatment is completed, the treated liquid in which the concentration of dimethylformamide in the liquid to be treated has become below the permissible concentration may be discharged as is or after removing the bacterial cells and/or the treated bacterial cells as necessary. Ru.

〔Example〕

The present invention will be explained in more detail with reference to Examples. Note that the present invention is not limited to the examples.

Example 1 Pure water 12, (NL)zs043g1. KHzPO
41.4g.

NaJPOa 2.1 g, MgSO4.7L00.
2g, CaC1g・2Hz030mg, FeCJ,
O, °XHz030mg, MnC1z°4)1z05m
g, ZnSO4'7H*05mg, Cu5Oa'
A medium adjusted to p)l 7.1 by adding 5HzO0,5ffig and 0.2g of yeast extract was used as a basal medium, and a dimethylformamide concentration of 0.5wt
χ+ 1 wtχ, 1.5wtχ, 2-tχ, 3-
A medium was prepared by adding dimethylformamide to give tχ and 5wtχ. Pseudomonas aminovorans D. 81 was inoculated into each of these media, and cultured at 30° C. for 7 days to examine the ability to assimilate dimethylformamides.

The results are shown in Table 1.

Table 1 Example 2 Per 12 pure water, (NH4) tsOa 3 g,
Kl (xPO41.4g.

NaJPOa 2.1g, MgSO4'7Hz00
．． 2g, CaC1z・2Hz03011L FeCJ
sOl・XHto 30'mg, MnC1z'4Hz
05mg, Zn5 (L'1Hz05■, CLISO4
°5H! OO, 5 mg, yeast extract 0.2 g, and dimethylformamide 5 g were added, and the medium 200- was adjusted to pH 7.0. Pour into a Erlenmeyer flask and heat to 120°C.
sterilized for 20 minutes.

Into this medium, a preculture solution of Shademonas aminovorans D81 obtained by culturing in advance in a medium similar to this (
Bacterial cell concentration 0. D, i+o-1,5) was inoculated at 1 vol x and cultured at 30°C for 50 hours.

The absorbance (0,0,616,%) and pH of the culture solution obtained were 2.3 and 7.5, respectively, and no dimethylformamide was detected in the culture supernatant. Ta. Note that the generation time was approximately 6.5 hours.

Example 3 From the composition of the basal medium in Example 1, CN
Separated from the pre-culture solution obtained by pre-cultivating in the same medium as in Example 2, nutrient components were added to the medium composition excluding zsOa, and the po was adjusted to 7.0. Shade Monas Aminovorans D81
1 g of bacterial cells were suspended, and while aerating and stirring, the pH and temperature of the culture solution were adjusted to 7.0 and 30, respectively.
It was kept at ℃.

It took about 30 hours until dimethylformamide was no longer detected in the factory effluent.

In each of the above Examples, dimethylformamide in the liquid was analyzed by gas chromatography.

Model: Shimadzu 7A GC (FI
D) “Column: Unisole
30T 5χ Uniport HP 80/
100Glass Co1cvn (3φX2m) - Column temperature near 0°C Flow rate: Nt (standard state) 30d/win.

〔Effect of the invention〕

The present invention efficiently decomposes dimethylformamide, which is a stable, difficult to decompose, and harmful substance.

This makes it possible to efficiently detoxify the harmful waste fluid containing dimethylformamide, which has extremely high value in terms of preserving environmental health.

Patent applicant: Mitsubishi Gas Chemical Co., Ltd. Representative Nagano Japanese book

Claims (1)

[Claims] Decomposing dimethylformamide in the liquid by contacting a liquid containing dimethylformamide with the cells of a bacterium belonging to the genus Pseudomonas that can assimilate and decompose dimethylformamide, and/or a bacterial cell-treated product of the bacterium, A method for removing dimethylformamide, the method comprising: removing dimethylformamide.