JP2002263659A - Method for killing legionella bacteria in water system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for killing Legionella bacteria in a water system so that Legionella bacteria living in the circulating cooling water of a freezing device, in a cool and hot water system such as a circulating hot water in a 24-hour bath, in a heat accumulating water system or the like can be killed by using non-halogen compounds and can be prevented from breeding. SOLUTION: The method for killing Legionella bacteria in a water system is carried out by adding maleimide to the water system where Legionella bacteria are living.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing Legionella spp. More specifically, the present invention provides
Removal of Legionella spp. In a water system that can eliminate and prevent the growth of Legionella spp. That survives in cold / hot water systems such as circulating cooling water in refrigeration systems, circulating hot water in 24-hour baths, and heat storage water systems. Bacterial method.

[0002]

2. Description of the Related Art In refrigeration systems used in air conditioners, refrigerators, freezers, and the like, circulating water cooled using an open-type cooling tower or the like is often used for efficient heat exchange. In such circulating water, microorganisms and the like from the outside easily enter and proliferate, causing a decrease in heat exchange efficiency of the heat exchanger due to slime or the like, and causing obstacles such as clogging of the filter, as well as pathogenic bacteria, especially Legionella spp. Proliferation and dispersal can cause special pneumonia, such as veterans' illness and Pontiac fever. As a countermeasure against such problems caused by microorganisms, an antibacterial agent is injected into the circulating water system to suppress the growth of bacteria, or the inside of the apparatus is physically cleaned and cleaned, or the apparatus is chemically cleaned using a cleaning agent. Methods have been used. Various compounds have been conventionally proposed as fungicides for eliminating Legionella spp., But there are many halogen-based compounds, and these compounds have recently been considered to have a problem with respect to the environment. New drugs are also required from the viewpoint of safety. In addition, even when a chemical exhibiting a bactericidal effect in a laboratory is used in an actually operating aqueous system, a sufficient effect is often not always obtained. On the other hand, it is known that maleimides have antibacterial activity. For example, Japanese Patent Publication No. 39-17546 discloses a fungicide for agriculture and industry containing maleimide or N-carbamoylmaleimide, which is applicable to prevention of rice blast and slime prevention of white water in a pulp production process. Is illustrated. Also,
JP-A-63-156703 discloses antifouling paint for ship bottoms,
2-halo-N- (2 ′, 6 ′) used for fishing net antifouling paints, etc.
A biocontrol agent in water containing (dialkylphenyl) maleimide has been proposed. However, it has not been known that maleimides are effective in removing Legionella spp. By adding them to a cooling water system or the like.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a Legionella genus living in a cold / hot water system such as a circulating cooling water for a refrigerating apparatus, a circulating hot water for a 24-hour bath, or a heat storage water system using a non-halogen compound. An object of the present invention is to provide a method for disinfecting Legionella spp. In a water system capable of eliminating bacteria and preventing its growth.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, maleimides have an excellent bactericidal effect against Legionella spp. Living in an aqueous system. The present invention has been completed based on this finding. That is, the present invention provides (1) a method of removing Legionella spp. In an aqueous system, wherein maleimides are added to an aqueous system in which Legionella spp. Is alive, and (2) maleimides are added. 2. The method for removing bacteria of the genus Legionella in an aqueous system according to claim 1, which is a compound represented by the general formula [1],

Embedded image(However, in the formula, R¹And R^TwoIs hydrogen or carbon number 1-5
Is an alkyl group of ^ThreeIs hydrogen, unsubstituted or
C1-C10 alkyl substituted by droxyl group
Group, unsubstituted or substituted with hydroxyl group
5-8 cycloalkyl groups, unsubstituted or hydroxy
Or a phenyl group substituted with
It is a benzyl group substituted with a xyl group. ), Provide
Things.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for removing Legionella spp. In an aqueous system according to the present invention, maleimides are added to an aqueous system in which Legionella spp. Is alive. Legionella spp. To which the method of the present invention can be applied is 1976
This is a new genus of Gram-negative polecillary bacillus, which was discovered and named after an outbreak of severe pneumonia of unknown origin, a so-called Legionnaires' disease in Philadelphia. Currently the reference species Legi
In addition to onella pneumophila (serogroup 11), many subspecies and serogroups are known, but the method of the present invention can be applied to all of these strains. By applying the method of the present invention, bacteria of the genus Legionella living in a cold / hot water system such as a circulating cooling water of a refrigerating device, a circulating hot water of a 24-hour bath, a heat storage water system, etc. are sterilized and their growth is prevented. Can be.

The maleimides used in the present invention are not particularly limited. For example, in addition to maleimide, compounds having a substituent at the nitrogen atom of the maleimide, compounds having a substituent at the 2- and / or 3-carbon atoms, Compounds having a condensed ring of a maleimide ring and a benzene ring can be exemplified. In the present invention, as the maleimide, a compound represented by the general formula [1] can be suitably used.

Embedded image In the general formula [1], R ¹ and R ² are hydrogen or an alkyl group having 1 to 5 carbon atoms, and R ³ is a hydrogen, an unsubstituted or an alkyl group having 1 to 10 carbon atoms substituted with a hydroxyl group. An unsubstituted or hydroxyl-substituted cycloalkyl group having 5 to 8 carbon atoms; an unsubstituted or hydroxyl-substituted phenyl group; or an unsubstituted or hydroxyl-substituted benzyl group. Examples of the compound represented by the general formula [1] include maleimide, N-methylmaleimide, N-ethylmaleimide, citraconic imide, N-methylcitraconic imide,
-Ethyl citraconic imide, 2,3-dimethylmaleimide, N-methyl-2,3-dimethylmaleimide, N-ethyl-2,3-dimethylmaleimide, N- (2-hydroxyethyl) maleimide , N-cyclohexylmaleimide, N-4-hydroxycyclohexylmaleimide, N-phenylmaleimide, Np-hydroxyphenylmaleimide, Np-hydroxybenzylmaleimide, and the like. One of these maleimides can be used alone, or two or more can be used in combination.

In the present invention, these maleimides can be used as they are, can be used as powders or tablets by blending with a bulking agent or other agents, or can be used as a liquid by dissolving in an appropriate solvent. You can also. As a solvent in the case of a liquid preparation, water can be suitably used, but a hydrophilic solvent can also be used if necessary. Examples of the hydrophilic solvent include alcohols, glycols, amides, glycol esters, esters, and the like. In the method of the present invention, the amount of maleimides added to the aqueous system in which the Legionella genus is alive is not particularly limited and can be appropriately selected according to the state of the aqueous system. It is preferably from 0.1 to 1,000 mg / L, more preferably from 0.5 to 100 mg / L, even more preferably from 1 to 30 mg / L. There is no particular limitation on the pH of the aqueous system to be applied, which is the normal pH range of 3
A range of about 10 to about 10 can be sufficiently used. In the method for removing bacteria of the genus Legionella of the present invention, if necessary, a biocide, a microbial growth inhibitor, a corrosion inhibitor,
A scale inhibitor, an antifoaming agent, a surfactant and the like can be used in combination. According to the method of the present invention, using a non-halogen compound, circulating cooling water of a refrigeration system, a cold and hot water system such as a circulating hot water of a 24-hour bath, sterilizing Legionella sp. Its proliferation can be prevented.

[0008]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. Comparative Example 1 In 1,000 mL of pure water, 10.0 g of yeast extract, 10.0 g of ACES buffer, 0.4 g of L-cysteine monohydrochloride,
0.25 g of soluble iron pyrophosphate, 1.0 of α-ketoglutaric acid
g, activated carbon powder 1.5 g and agar agar 15.0 g.
Of 6.9 was prepared. Legionella pneumophila was inoculated on the plate medium and cultured at 36 ° C. for 2 days. This cultured Legionella bacterium was suspended in a phosphate buffer at pH 7 to a level of 10 ⁴ cells / mL. This solution is used as a Legionella standard solution. After 0.1 mL of this Legionella standard solution was applied to a BCYEα plate medium and cultured at 36 ° C. for 5 days, the number of viable bacteria was measured by counting the number of colonies, and it was found to be 2.5 × 10 ⁴ cells / mL. Was. Example 1 Each 1 mL of the Legionella standard solution prepared in Comparative Example 1 was placed in three culture flasks. Then, maleimide was added to each flask to a concentration of 1 mg / L, 5 mg / L or 10 mg / L, and cultured with shaking at 37 ° C. for 24 hours. The number of viable bacteria in was measured. When the maleimide concentration is 1 mg / L, the number of viable bacteria is 3.8 × 10 ³ and the concentration is 5 mg / L or 10 mg / L.
At this time, the number of viable bacteria was less than 10 ² . Example 2 The same operation as in Example 1 was performed except that N-methylmaleimide was used instead of maleimide. When the concentration of N-methylmaleimide was 1 mg / L, the number of viable bacteria was 3.4 × 10 ³ , and when the concentration was 5 mg / L or 10 mg / L, the number of viable bacteria was less than 10 ² . Comparative Example 2 Instead of maleimide, 5-chloro-2-methyl-4-
10% by weight of isothiazolin-3-one and 2-methyl-4
Using an aqueous solution containing 4% by weight of isothiazolin-3-one [Rohm and Haas, KATHON WT]
Except that the total concentration of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one was 1 mg / L, 5 mg / L or 10 mg / L. The same operation as in 1 was performed. When the concentration of the 4-isothiazolin-3-one compound is 1 mg / L, the number of viable bacteria is 2.
When the concentration was 1 × 10 ⁴ and the concentration was 5 mg / L or 10 mg / L, the viable cell count was less than 10 ² . Comparative Example 3 The same operation as in Example 1 was performed, except that 2-bromo-2-nitropropane-1,3-diol [generic name: bronopol] was used instead of maleimide. 2-bromo-
When the concentration of 2-nitropropane-1,3-diol is 1 mg / L, the number of viable bacteria is 2.3 × 10 ⁴ , and when the concentration is 5 mg / L, the number of viable bacteria is 6.5 × 10 ³ . Yes, concentration 10mg / L
At this time, the viable cell count was less than 10 ² . Examples 1-2
Table 1 shows the results of Comparative Examples 1 to 3.

[0009]

[Table 1]

As can be seen from Table 1, when the number of viable bacteria was compared when the concentration of each drug was 1 mg / L, it was found that in Examples 1 and 2 using maleimide or N-methylmaleimide,
^{In the} case of Comparative Examples 2-3 using a conventionally known halogen-based bactericide, which is of the order of ³ / mL, since it is of the order of 10 ⁴ / mL, maleimide or N-methylmaleimide does not contain halogen. Nevertheless, it can be seen that it has superior bactericidal activity to Legionella bacteria than known halogen-based bactericides.

[0011]

According to the method for removing bacteria of the genus Legionella in an aqueous system according to the present invention, a cold / hot water system such as a circulating cooling water for a refrigerating apparatus, a circulating hot water for a 24-hour bath, or a heat storage water system is used by using a non-halogen compound. For example, the living Legionella spp. Can be eliminated and its growth can be prevented.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C02F 1/50 540 C02F 1/50 540D A01N 37/32 101 A01N 37/32 101 F24F 5/00 101 F24F 5 / 00101Z F24H 1/00 602 F24H 1/00 602L

Claims (2)

[Claims] 1. A method for disinfecting Legionella spp. In a water system, comprising adding a maleimide to an aqueous system in which the Legionella spp. Is alive. 2. A maleimide represented by the general formula [1]:
2. The genus Legionella in an aqueous system according to claim 1, which is a compound.
How to remove bacteria. Embedded image(However, in the formula, R¹And R^TwoIs hydrogen or carbon number 1-5
Is an alkyl group of ^ThreeIs hydrogen, unsubstituted or
C1-C10 alkyl substituted by droxyl group
Group, unsubstituted or substituted with hydroxyl group
5-8 cycloalkyl groups, unsubstituted or hydroxy
Or a phenyl group substituted with
It is a benzyl group substituted with a xyl group. )