JP6779040B2 - Composition for suppressing biofilm formation - Google Patents

Description

The present invention relates to a composition for suppressing biofilm formation and a method for suppressing biofilm formation.

Systems that use water media, such as factory equipment and building cooling systems that use water-cooled cooling towers, and cooling pools, have been conventionally used. In such systems, microbial contamination of the water used is a problem. For example, in a cooling system using a water-cooled cooling tower, microorganisms mixed in the cooling water form a biofilm in the piping, especially in the heat exchanger. The biofilm formed on the heat exchanger reduces the efficiency of heat exchange and increases the power consumption of the cooling system. Regular water replacement and cleaning are required to prevent biofilm formation, which increases system maintenance costs.

Conventionally, a bactericide such as a chlorine-based chemical has been used to prevent a biofilm in a cooling system using a water-cooled cooling tower. However, chlorine-based chemicals have a problem of damage to piping and equipment, cannot be used at a concentration that can sufficiently sterilize, and cannot suppress biofilm formation for a long period of time.

Patent Document 1 discloses that a liquid composition having a pH of 12 or higher containing N-alkyl-substituted hydroxylamine and an alkali metal hydroxide together with a quinone derivative is used for boiler corrosion protection. Quinone compounds are also known as antibacterial substances. For example, Patent Documents 2 and 3 disclose that benzoquinone or hydroquinone has antibacterial activity against staphylococci, P. acnes, or propionic acid bacteria. Patent Document 4 discloses that a benzoquinone or a derivative of hydroquinone has antibacterial activity against Staphylococcus aureus and P. acnes. Non-Patent Document 1 discloses that quinone or hydroquinone in which the 2-position is substituted with an alkyl or alkenyl group exhibits antibacterial activity against Bacillus subtilis, Micrococcus or Candida. Non-Patent Document 2 discloses that tert-butylhydroquinone and tert-butylbenzoquinone have antibacterial activity against Staphylococcus aureus and inhibit the formation of biofilms by the bacteria. On the other hand, there have been few reports on the antibacterial action of the above compounds against Gram-negative bacteria, and the reported antibacterial activity has not been large. Non-Patent Document 1 does not specify the minimum inhibitory concentration (MIC) for Gram-negative bacteria, and Non-Patent Document 2 has a minimum inhibitory concentration (MIC) of tert-butylhydroquinone for Escherichia coli of 512 ppm. It is described as. Patent Document 4 describes that dimethyl and dibutylresorcinol have antibacterial activity against Staphylococcus aureus and P. acnes. Non-Patent Document 3 describes 4-isopropylresorcinol as an antibacterial substance against Mycobacterium tuberculosis. On the other hand, it has not been clarified so far that these compounds have antibacterial action against gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa. Patent Document 5 describes 4-hexylresorcinol as an antibacterial substance against P. acnes. In addition, Non-Patent Document 4 describes that 4-hexylresorcinol suppressed the growth of Pseudomonas spp.

JP-A-2015-68631 International Publication No. 2007/096601 Japanese Patent Publication No. 2008-535814 International Publication No. 2006/100196 International Publication No. 2004/091595

J Nat Prod, 1994, 57 (12): 1711-1716 J Antimicrob Chemother, 2013, 68 (6): 1297-1304 Anti-Infective Agents, 2012, 10 (1): 6-14 Microbiology, 2005, 74 (2): 128-135

The present invention provides a composition for suppressing biofilm formation and a method for suppressing biofilm, which can effectively suppress biofilm formation in an aqueous system.

The present inventors have found that the quinone compound and the chelating agent effectively suppress biofilm formation even when used at a low concentration that does not inhibit the growth of microorganisms.

Therefore, the present invention provides a composition for suppressing biofilm formation, which contains a quinone compound and a chelating agent.
The present invention also provides a method for suppressing biofilm formation, which comprises adding a quinone compound and a chelating agent to an aqueous liquid.

According to the biofilm formation suppressing composition of the present invention and the biofilm suppressing method of the present invention, biofilm formation can be effectively performed even when used at a low concentration that does not inhibit the growth of microorganisms. It can be suppressed.

The present invention relates to the suppression of biofilm formation in aqueous liquids. The present invention also relates to the suppression of biofilm formation in water-based systems. The present invention provides a composition for suppressing biofilm formation containing a quinone compound and a chelating agent. The present invention also provides a method for suppressing biofilm formation using a quinone compound and a chelating agent.

In the present specification, the "water system" means a system provided with pipes, tanks, pools, etc., which functions by flowing or storing water-based liquids, for example, factory equipment using a water-cooled cooling tower. Building cooling systems, industrial cooling pools, industrial water supply, water storage or drainage channels, wastewater treatment equipment, running water heating systems, tanks and pools, filtration equipment, etc. Preferably, the aqueous system to which the composition for suppressing biofilm formation of the present invention is applied has a temperature at which at least a part thereof is likely to form a biofilm, for example, preferably 5 ° C. or higher, more preferably 10 ° C. or higher, and further. It is an aqueous system that can reach preferably 15 ° C. or higher, more preferably 20 ° C. or higher, and even more preferably 25 ° C. or higher.

As used herein, the "aqueous liquid" may be simply water or a liquid containing water and other compounds. Examples of the other compound include organic solvents, salts, antibacterial and antifungal agents, antiseptic and fungicides, antibiotics, penetration promoters, surfactants, deodorants and fragrances. The content of water in the aqueous liquid is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, still more preferably 99% by mass or more, and preferably 100% by mass or less. is there.

The "water-based liquid" preferably includes a water-based liquid used for industrial purposes, and more preferably a water-based liquid used in the above-mentioned water-based system, for example, a cooling system for factory equipment or a building using a water-cooled cooling tower. Water-based medium used for water-based heating system, water-based medium used for running hot water system, drainage of wastewater treatment equipment, or water-based liquid in industrial cooling pool, industrial water supply, water storage or drainage route, or in tank or pool , Etc. are included.

Preferably, the composition for suppressing biofilm formation of the present invention is used for suppressing biofilm formation in the water-based liquid flowing or stored in the water-based system and the equipment, equipment, etc. of the water-based system in contact with the water-based liquid. To. More preferably, the composition for suppressing biofilm formation of the present invention is used for suppressing biofilm formation in equipment and devices of a water-cooled cooling tower, or an aqueous liquid (for example, cooling water of a water-cooled cooling tower) contained therein. used.

Biofilms that occur in water systems as described above include gram-negative microorganisms such as Pseudomonas, Sphingomonas, and Sphingopyxis, such as Pseudomonas aeruginosa. In addition, gram-negative microorganisms of the genera Klebsiella, Flavobacterium and Roseomonas have been reported as microorganisms present in biofilms in water-cooled cooling towers (Biofouling 2011, 27 (4) 393-402, Biocontrol Science 2013, 18 (Biocontrol Science 2013, 18). 4) 205-209).

Conventionally, biofilms have been prevented by sterilizing the causative microorganisms of the biofilms with a fungicide. On the other hand, in the present invention, the formation of the biofilm may be suppressed by sterilizing the microorganism that causes the biofilm with a quinone compound, but the biofilm may be suppressed by using the quinone compound at a low concentration. It is also possible to suppress biofilm formation without inhibiting the growth of the causative microorganism. A method of suppressing the formation of a biofilm without inhibiting the growth of the causative microorganism is more preferable from the viewpoint of suppressing the generation of resistant bacteria and suppressing the environmental load due to the high concentration of the drug.

Composition for suppressing biofilm formation The composition for suppressing biofilm formation of the present invention contains a quinone compound and a chelating agent. The quinone compound and the chelating agent work together as an active ingredient for suppressing biofilm formation.

(Quinone compound)
The quinone-based compound used in the present invention is a compound having one benzene ring having two or three ketone groups, and the benzene ring may be substituted with an alkyl group. The alkyl group substituting the benzene ring preferably has 1 or more and 12 or less carbon atoms, more preferably 1 or more and 8 or less carbon atoms, still more preferably 1 or more and 6 or less carbon atoms, and still more preferably 1 or more and 3 or less carbon atoms. It is a chain or branched alkyl group, and examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a 2-ethylhexyl group and the like. A methyl group, an ethyl group, a propyl group, and an isopropyl group are preferable. The number of alkyl substituents in the benzene ring is preferably 1 or more and 3 or less, and more preferably 1. Each alkyl substituent can be independently selected from the group of alkyl groups described above.

The ketone group of the benzene ring of the quinone compound used in the present invention may be reduced to a hydroxy group, and one of the hydroxy groups may be alkoxylated. The alkoxy group preferably has 1 or more and 3 or less carbon atoms, more preferably a methoxy group, an ethoxy group, a propoxy group, or the like, and further preferably a methoxy group.

Preferred examples of the quinone-based compound used in the present invention include hydroquinone substituted with a hydroxyl group or an alkyl group, p-benzoquinone substituted with a hydroxyl group or an alkyl group, and alkylresorcinol. More preferably, examples of the quinone-based compound used in the present invention include compounds represented by the following formulas (I) to (III).

In the above formula (I), R ₁ represents a hydroxyl group or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₂ , R ₃ and R ₄ independently form a hydrogen or methyl group, respectively. Represent. In a preferred embodiment, R ₁ is a hydroxyl group or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₂ , R ₃ and R ₄ are both hydrogen, and the carbon atoms 1 to 4 are said to be hydrogen. The linear or branched alkyl group of is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group or a t-butyl group. In another preferred embodiment, R ₁ is a methyl group, R ₃ is a hydrogen, and R ₂ and R ₄ are a methyl group on one side and a hydrogen on the other, or both are methyl groups. In another preferred embodiment, R ₁ , R ₂ , R ₃ and R ₄ are all methyl groups.

In the above formula (II), R ₅ represents a hydroxyl group or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₆ , R ₇ and R ₈ independently form a hydrogen or methyl group, respectively. Represent. In a preferred embodiment, R ₅ is a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₆ , R ₇ and R ₈ are both hydrogen, and the linear chain having 1 to 4 carbon atoms. Alternatively, the branched alkyl group is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group or a t-butyl group.

In the above formula (III), R ₉ , R ₁₀ and R ₁₁ each independently represent hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms, and the linear chain thereof. Alternatively, the branched alkyl group is preferably from the group consisting of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and a 2-ethylhexyl group. Be selected. However, R ₉ , R ₁₀ and R ₁₁ do not become hydrogen at the same time. In a preferred embodiment, any one of R ₉ , R ₁₀ and R ₁₁ is a linear or branched alkyl group having 1 to 6 carbon atoms, and the rest are all hydrogen. More preferably, any one of R ₉ , R ₁₀ and R ₁₁ is a linear or branched alkyl group having 1 to 5 carbon atoms, and the rest are all hydrogen. More preferably, any one of R ₉ , R ₁₀ and R ₁₁ is a linear or branched alkyl group having 2 to 5 carbon atoms, and the rest are all hydrogen. In another preferred embodiment, any two of R ₉ , R ₁₀ and R ₁₁ are linear alkyl groups having 1 to 6 carbon atoms and the rest is hydrogen. More preferably, any two of R ₉ , R ₁₀ and R ₁₁ are linear alkyl groups having 1 to 5 carbon atoms, and the rest is hydrogen. More preferably, any two of R ₉ , R ₁₀ and R ₁₁ are linear alkyl groups having 2 to 5 carbon atoms, and the rest is hydrogen. In formula (III), the linear or branched alkyl group represented by R ₉ , R ₁₀ or R ₁₁ is preferably composed of a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group and a t-butyl group. Selected from the group of

The quinone-based compound used in the present invention may be any one of the above-mentioned quinone-based compounds, or may be a combination of any two or more of them. Preferably, the quinone-based compound used in the present invention is any one of the compounds represented by the above formulas (I) to (III), or a combination of any two or more of them.

Further preferred examples of the quinone compounds used in the present invention are p-torquinone, 2-methylhydroquinone, ethylquinol, 2-butylhydroquinone, tert-butylhydroquinone, 2,6-dimethylhydroquinone, 2,3-dimethylhydroquinone. , 2,3,5-trimethylhydroquinone, tetramethylhydroquinone, hydroxyhydroquinone, 3,5-dimethylbenzoquinone, p-benzoquinone and hydroquinone such as tert-butylbenzoquinone, and 4-butylresorcinol (lucinol), 4-hexylresorcinol, Included is one or more selected from the group consisting of alkylresorcinols such as 5-methylresorcinol, 5-pentylresorcinol, 2-propylresorcinol, 2,5-dimethylresorcinol, 2-methylresorcinol, and 4-isopropylresorcinol. Of these, from the viewpoint of suppressing biofilm formation, one or more selected from the group consisting of p-torquinone and 2-methylhydroquinone is still preferable.

(Chelating agent)
Examples of the chelating agent used in the present invention include carboxylic acid-based, phosphoric acid-based, and phosphonic acid-based chelating agents. Examples of the carboxylic acid-based chelating agent include polyvalent carboxylic acid, hydroxycarboxylic acid, aminocarboxylic acid, phosphonocarboxylic acid, and salts thereof. Examples of the polyvalent carboxylic acid include citric acid, succinic acid, malic acid, fumaric acid, tartaric acid, malonic acid, maleic acid and the like. Examples of the hydroxycarboxylic acid include aliphatic hydroxycarboxylic acids such as citric acid and malic acid. Examples of aminocarboxylic acids include ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), iminodiacetic acid, diethylenetriaminetetraacetic acid (DPTA), N-hydroxyethyl-ethylenediaminetriacetic acid (HEDTA), and methylglycine diacetic acid (MGDA). , Aspartate diacetic acid (ASDA), glutamate diacetic acid (GLDA) and the like. Examples of the phosphonocarboxylic acid include 2-phosphonobutane-1,2,4-tricarboxylic acid. Examples of the phosphoric acid-based chelating agent include tripolyphosphoric acid and salts thereof. Examples of the phosphonic acid-based chelating agent include hydroxyphosphonic acids such as 1-hydroxyetidron-1,1-diphosphonic acid (HEDP), aminophosphonic acids such as aminotrimethylenephosphonic acid (ATMP), and salts thereof. .. Of these, as the chelating agent used in the present invention, one or more selected from the group consisting of aminocarboxylic acid, phosphonocarboxylic acid, hydroxycarboxylic acid, hydroxyphosphonic acid, and salts thereof is preferable. Examples of the salt include alkali metal salts, ammonium salts, amine salts and the like. The salt is preferably an alkali metal salt, more preferably a sodium salt or a potassium salt.

(composition)
The composition for suppressing biofilm formation of the present invention may be a composition composed of the above-mentioned quinone compound and a chelating agent, but may contain other components. For example, the composition for suppressing biofilm formation of the present invention may contain a solvent such as water or an organic solvent from the viewpoint of mixing the quinone-based compound and the chelating agent. Preferred organic solvents include methanol, ethanol, dipropylene glycol, diethylene glycol, diacetone alcohol, diethylene glycol monomethyl ether, propylene glycol, and mixed solvents thereof.

Furthermore, examples of other components that may be contained in the composition for suppressing biofilm formation of the present invention include antibacterial antifungal agents, antiseptic fungicides, antibiotics, penetration promoters, surfactants, and deodorants. Examples include agents and fragrances. The type and concentration of the other components are not particularly limited as long as they do not inhibit the biofilm formation inhibitory action of the quinone compound and the chelating agent.

In the composition for suppressing biofilm formation of the present invention, the content of the quinone-based compound is preferably 0.1% by mass or more, more preferably 0, from the viewpoint of the solubility of the quinone-based compound and the action of suppressing biofilm formation. .5% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, still more preferably 5% by mass or more, and preferably 90% by mass or less, more preferably 70% by mass or less, further It is preferably 50% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less. Alternatively, the content of the quinone compound in the composition for suppressing biofilm formation of the present invention is preferably 0.1 to 90% by mass, more preferably 0.5 to 70% by mass, and further preferably 1 to 50% by mass. %, More preferably 1 to 30% by mass, still more preferably 1 to 20% by mass, still more preferably 3 to 20% by mass, still more preferably 5 to 20% by mass.

In the composition for suppressing biofilm formation of the present invention, the content of the chelating agent is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, still more preferably, from the viewpoint of the biofilm formation suppressing action. 0.3% by mass or more, more preferably 0.5% by mass or more, and preferably 90% by mass or less, more preferably 70% by mass or less, still more preferably 50% by mass or less, still more preferably 30% by mass. Hereinafter, it is more preferably 20% by mass or less. Alternatively, the content of the chelating agent in the composition for suppressing biofilm formation of the present invention is preferably 0.05 to 90% by mass, more preferably 0.05 to 70% by mass, still more preferably 0.1 to 50%. It is by mass, more preferably 0.3 to 30% by mass, still more preferably 0.5 to 20% by mass.

The contents of the quinone compound and the chelating agent in the composition for suppressing the formation of the biofilm of the present invention are preferably 0.1 to 90% by mass and 0.05 to 90% by mass, more preferably 1 to 50% by mass, respectively. % And 0.1 to 50% by mass, more preferably 1 to 20% by mass and 0.3 to 30% by mass, still more preferably 3 to 20% by mass and 0.3 to 30% by mass, still more preferably 5 to 20%. It is mass% and 0.5 to 20 mass%.

Further, the content of the chelating agent in the composition for suppressing biofilm formation of the present invention is preferably 0.1 part by mass or more with respect to 100 parts by mass of the quinone-based compound from the viewpoint of the biofilm formation suppressing action. It is more preferably 0.5 parts by mass or more, further preferably 1 part by mass or more, further preferably 3 parts by mass or more, still more preferably 5 parts by mass or more, still more preferably 7 parts by mass or more, and on the other hand, from the viewpoint of economic efficiency. From 100 parts by mass of the quinone compound, preferably 5000 parts by mass or less, more preferably 2000 parts by mass or less, still more preferably 1000 parts by mass or less, still more preferably 700 parts by mass or less, still more preferably 500 parts by mass. Hereinafter, it is more preferably 300 parts by mass or less.

Alternatively, the content of the chelating agent in the biofilm formation suppressing composition of the present invention is preferably 0.1 to 5000 parts by mass, more preferably 0.5 to 2000 parts by mass with respect to 100 parts by mass of the quinone compound. Parts, more preferably 1 to 1000 parts by mass, still more preferably 3 to 700 parts by mass, still more preferably 5 to 500 parts by mass, still more preferably 7 to 300 parts by mass.

In the composition for suppressing biofilm formation of the present invention, the total content of the quinone compound and the chelating agent is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, still more preferably. Is 7% by mass or more, and preferably 100% by mass or less, more preferably 80% by mass or less, still more preferably 50% by mass or less, still more preferably 30% by mass or less. Alternatively, the total content of the quinone compound and the chelating agent in the composition for suppressing biofilm formation of the present invention is preferably 1 to 100% by mass, more preferably 3 to 80% by mass, still more preferably 5 to 50. It is by mass, more preferably 7 to 30% by mass.

The composition for suppressing biofilm formation of the present invention may contain an organic solvent as an optional component. The amount of the organic solvent in the composition is preferably 95% by mass or less, more preferably 93% by mass or less, and preferably 0% by mass or more, more preferably 30% by mass or more, still more preferably 50% by mass. Above, more preferably 70% by mass or more. Alternatively, the content of the organic solvent in the composition for suppressing biofilm formation of the present invention is preferably 0 to 95% by mass, more preferably 0 to 93% by mass, still more preferably 30 to 95% by mass, still more preferably. It is 30 to 93% by mass, more preferably 50 to 95% by mass, still more preferably 50 to 93% by mass, still more preferably 70 to 95% by mass, still more preferably 70 to 93% by mass.

Biofilm formation inhibitory method The present invention also provides a biofilm formation inhibitory method using the above-mentioned quinone compound and a chelating agent. Preferably, the method of the present invention is a method for suppressing biofilm formation in an aqueous system. The method of the present invention comprises adding the above-mentioned quinone-based compound and a chelating agent to an aqueous liquid, preferably an aqueous liquid used in the above-mentioned aqueous system. In the method of the present invention, the composition for suppressing biofilm formation of the present invention containing the above-mentioned quinone compound and a chelating agent may be added to the aqueous liquid, and the composition may be added to water, an organic solvent, or the like. The diluted solution diluted with the above may be added, or the above-mentioned quinone compound and the chelating agent may be added separately. The aqueous liquid to which the quinone compound and the chelating agent are added is also simply referred to as a "treatment liquid" in the following specification.

In the present invention, the concentration of the quinone compound in the treatment liquid is preferably 1 ppm or more, more preferably 2 ppm or more, still more preferably 3 ppm or more, still more preferably 5 ppm or more, still more preferably 5 ppm or more, from the viewpoint of suppressing biofilm formation. 7 ppm or more, more preferably 8 ppm or more, further preferably 9 ppm or more, still more preferably 10 ppm or more, and on the other hand, from the viewpoint of economy, preferably 1400 ppm or less, more preferably 1000 ppm or less, still more preferably 500 ppm or less, further. It is preferably 270 ppm or less, more preferably 200 ppm or less, still more preferably 150 ppm or less, still more preferably 100 ppm or less, still more preferably 70 ppm or less, still more preferably 60 ppm or less, still more preferably 50 ppm or less, still more preferably 40 ppm or less, still more preferably. It is 30 ppm or less, more preferably 20 ppm or less, still more preferably 15 ppm or less. In this specification, ppm represents mass ppm.

Alternatively, the concentration of the quinone compound in the treatment liquid is preferably 1 to 1400 ppm, more preferably 2 to 1000 ppm, more preferably 3 to 500 ppm, still more preferably 5 to 270 ppm, still more preferably 5 to 200 ppm, still more preferably. 5 to 150 ppm, more preferably 5 to 100 ppm, still more preferably 5 to 70 ppm, still more preferably 5 to 60 ppm, still more preferably 5 to 50 ppm, still more preferably 5 to 40 ppm, still more preferably 5 to 30 ppm, still more preferably 5 It is ~ 20 ppm, more preferably 7 to 20 ppm, still more preferably 8 to 20 ppm, still more preferably 9 to 20 ppm, still more preferably 10 to 20 ppm, still more preferably 10 to 15 ppm.

More preferably, in the present invention, the quinone compound is used in an amount such that the concentration thereof in the treatment liquid is less than the minimum inhibitory concentration (MIC) of the causative microorganism of the biofilm.

In the present invention, the concentration of the chelating agent in the treatment liquid is preferably 0.05 ppm or more, more preferably 0.1 ppm or more, still more preferably 0.3 ppm or more, still more preferably 0, from the viewpoint of suppressing biofilm formation. 5.5 ppm or more, more preferably 1 ppm or more, still more preferably 2 ppm or more, on the other hand, from the viewpoint of economy, preferably 1000 ppm or less, more preferably 500 ppm or less, still more preferably 100 ppm or less, still more preferably 70 ppm or less. It is more preferably 50 ppm or less, further preferably 40 ppm or less, still more preferably 30 ppm or less, still more preferably 25 ppm or less, still more preferably 20 ppm or less.

Alternatively, the concentration of the chelating agent in the treatment liquid is preferably 0.05 to 1000 ppm, more preferably 0.1 to 500 ppm, still more preferably 0.3 to 100 ppm, still more preferably 0.3 to 70 ppm, still more preferably. 0.3 to 50 ppm, more preferably 0.3 to 40 ppm, still more preferably 0.3 to 30 ppm, still more preferably 0.3 to 20 ppm, still more preferably 0.5 to 20 ppm, still more preferably 1 to 20 ppm, further. It is preferably 2 to 20 ppm.

The preferred concentrations of the quinone compound and the chelating agent in the treatment liquid are preferably 1 to 1400 ppm and 0.05 to 1000 ppm, more preferably 5 to 200 ppm and 0.3 to 100 ppm, respectively, and further preferably 5 It is ~ 50 ppm and 0.3-30 ppm, more preferably 5-30 ppm and 0.5-20 ppm.

Further, in the present invention, the amount of the chelating agent added to the aqueous liquid is preferably 0.1 part by mass or more, more preferably 0 parts by mass, based on 100 parts by mass of the quinone-based compound from the viewpoint of suppressing biofilm formation. It is 5 parts by mass or more, more preferably 1 part by mass or more, further preferably 3 parts by mass or more, further preferably 5 parts by mass or more, still more preferably 7 parts by mass or more, and on the other hand, from the viewpoint of economic efficiency, it is a quinone type. With respect to 100 parts by mass of the compound, preferably 5000 parts by mass or less, more preferably 2000 parts by mass or less, further preferably 1000 parts by mass or less, still more preferably 700 parts by mass or less, still more preferably 500 parts by mass or less, still more preferably. It is 300 parts by mass or less.

Alternatively, in the present invention, the amount of the chelating agent added to the aqueous liquid is preferably 0.1 to 5000 parts by mass, more preferably 0.5 to 2000 parts by mass, based on 100 parts by mass of the quinone compound. It is preferably 1 to 1000 parts by mass, more preferably 3 to 700 parts by mass, still more preferably 5 to 500 parts by mass, still more preferably 7 to 300 parts by mass.

In the method of the present invention, the concentrations of the quinone compound and the chelating agent in the treatment liquid need not be maintained in the above-mentioned predetermined ranges at all times, and when necessary or periodically, the above-mentioned predetermined ranges It should be adjusted to and maintained for a certain period of time. For example, the quinone compound and the chelating agent can be added to the aqueous liquid at the same time or separately. From the viewpoint of the biofilm formation inhibitory effect, the concentration of the quinone compound and the chelating agent in the treatment liquid is kept within the above-mentioned predetermined range, preferably 24 hours or more, more preferably 36 hours or more, still more preferably 40 hours or more. It is desirable to maintain. The time for keeping the concentrations of the quinone compound and the chelating agent in the above-mentioned predetermined range in the method of the present invention is preferably 240 hours or less, more preferably 120 hours or less.

The temperature of the water-based liquid to be treated in the method of the present invention and the temperature of the treatment liquid can be appropriately set according to the water-based system in which the water-based liquid is used, but each is independently, preferably 5 ° C. or higher. More preferably 10 ° C. or higher, further preferably 15 ° C. or higher, still more preferably 20 ° C. or higher, still more preferably 25 ° C. or higher, preferably 60 ° C. or lower, more preferably 55 ° C. or lower, still more preferably 50 ° C. or lower. is there.

The present invention also provides the use of a combination of a quinone compound and a chelating agent for suppressing biofilm formation. Preferably, a composition containing a quinone compound and a chelating agent is used to suppress biofilm formation. Also preferably, the use is for suppressing biofilm formation in water-based systems or water-based liquids. The type, concentration, and method of use of the quinone compound and the chelating agent are as described above.

The present invention also includes the following substances, manufacturing methods, uses or methods as exemplary embodiments. However, the present invention is not limited to these embodiments.

[1] A composition for suppressing biofilm formation, which contains a quinone compound and a chelating agent.

[2] The composition according to [1], which is preferably used for suppressing biofilm formation in an aqueous liquid or an aqueous system using an aqueous liquid.

[3] A method for suppressing biofilm formation, which comprises adding a quinone compound and a chelating agent to an aqueous liquid.

[4] The method according to [3], wherein biofilm formation is preferably suppressed in the water-based liquid or a water-based system using the water-based liquid.

[5] Use of a combination of a quinone compound and a chelating agent for suppressing biofilm formation.

[6] The use according to [5], wherein the above use is preferably a water-based liquid or a use for suppressing biofilm formation in a water-based system using a water-based liquid.

[7] The use according to [5] or [6], wherein a composition containing a quinone compound and a chelating agent is preferably used.

[8] In any one of the above [1] to [7], the chelating agent is
Preferably, it is a carboxylic acid-based, phosphoric acid-based, or phosphonic acid-based chelating agent.
More preferably, it is one or more selected from the group consisting of aminocarboxylic acid, phosphonocarboxylic acid, hydroxycarboxylic acid, hydroxyphosphonic acid, and salts thereof.

[9] In any one of the above [1] to [8], the quinone-based compound is
Preferably, it is a compound having one benzene ring having two or three ketone groups.
The ketone group may be reduced to a hydroxy group, and one of the hydroxy groups may be alkoxylated.
The benzene ring is substituted with 1 to 3, preferably 1 alkyl group.
Each of the alkyl groups is independently, preferably a linear chain having 1 or more and 12 or less carbon atoms, more preferably 1 or more and 8 or less carbon atoms, still more preferably 1 or more and 6 or less carbon atoms, and further preferably 1 or more and 3 or less carbon atoms. Or a branched alkyl group, more preferably from a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group and a 2-ethylhexyl group. Selected from the group of

（式（I）中、Ｒ₁は、水酸基、又は炭素数１〜４の直鎖もしくは分枝鎖アルキル基を表し、Ｒ₂、Ｒ₃及びＲ₄は、それぞれ独立に、水素又はメチル基を表す。
より好ましくは、
Ｒ₁が水酸基又は炭素数１〜４の直鎖もしくは分枝鎖アルキル基であり、かつＲ₂、Ｒ₃及びＲ₄がともに水素であるか、
Ｒ₁がメチル基であり、Ｒ₃が水素であり、かつＲ₂及びＲ₄が、一方がメチル基で他方が水素であるかもしくはともにメチル基であるか、又は、
Ｒ₁、Ｒ₂、Ｒ₃及びＲ₄はともにメチル基である；
式（II）中、Ｒ₅は、水酸基、又は炭素数１〜４の直鎖もしくは分枝鎖アルキル基を表し、Ｒ₆、Ｒ₇及びＲ₈は、それぞれ独立に、水素又はメチル基を表す。より好ましくは、Ｒ₅は炭素数１〜４の直鎖もしくは分枝鎖アルキル基であり、かつＲ₆、Ｒ₇及びＲ₈はともに水素である；
式（III）中、Ｒ₉、Ｒ₁₀及びＲ₁₁は、それぞれ独立に、水素、又は炭素数１〜８の直鎖もしくは分枝鎖アルキル基を表す（ただし、Ｒ₉、Ｒ₁₀及びＲ₁₁が同時に水素になることはない）。より好ましくは、Ｒ₉、Ｒ₁₀及びＲ₁₁のいずれか１つが炭素数１〜６の直鎖もしくは分枝鎖アルキル基であり、かつ残りがいずれも水素であるか、又はＲ₉、Ｒ₁₀及びＲ₁₁のいずれか２つが炭素数１〜６の直鎖アルキル基であり、かつ残りが水素である。） [10] In any one of the above [1] to [8], the quinone-based compound is
Preferably, it is one or more selected from the group consisting of the compounds represented by the formulas (I) to (III):

(In formula (I), R ₁ represents a hydroxyl group or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₂ , R ₃ and R ₄ independently form a hydrogen or methyl group, respectively. Represent.
More preferably
Whether R ₁ is a hydroxyl group or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₂ , R ₃ and R ₄ are all hydrogen.
R ₁ is a methyl group, R ₃ is a hydrogen, and R ₂ and R ₄ are either a methyl group and one hydrogen or both methyl groups, or
R ₁ , R ₂ , R ₃ and R ₄ are all methyl groups;
In formula (II), R ₅ represents a hydroxyl group or a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₆ , R ₇ and R ₈ independently represent a hydrogen or methyl group, respectively. .. More preferably, R ₅ is a linear or branched alkyl group having 1 to 4 carbon atoms, and R ₆ , R ₇ and R ₈ are all hydrogen;
In formula (III), R ₉ , R ₁₀ and R ₁₁ independently represent hydrogen or a linear or branched alkyl group having 1 to 8 carbon atoms (where R ₉ , R ₁₀ and R _11). Does not become hydrogen at the same time). More preferably, any one of R ₉ , R ₁₀ and R ₁₁ is a linear or branched alkyl group having 1 to 6 carbon atoms, and the rest are all hydrogen, or R ₉ , R ₁₀ Any two of R ₁₁ and R ₁₁ are linear alkyl groups having 1 to 6 carbon atoms, and the rest is hydrogen. )

[11] In any one of the above [1] to [8], the quinone-based compound is
Preferably, p-torcinone, 2-methylhydroquinone, ethylquinol, 2-butylhydroquinone, tert-butylhydroquinone, 2,6-dimethylhydroquinone, 2,3-dimethylhydroquinone, 2,3,5-trimethylhydroquinone, tetramethyl Hydroquinone, hydroxyhydroquinone, 3,5-dimethylbenzoquinone, tert-butylbenzoquinone, 4-butylresorcinol, 4-hexylresorcinol, 5-methylresorcinol, 5-pentylresorcinol, 2-propylresorcinol, 2,5-dimethylresorcinol, 2 One or more selected from the group consisting of -methylresorcinol and 4-isopropylresorcinol.
More preferably, it is one or more selected from the group consisting of p-torquinone and 2-methylhydroquinone.

[12] In any one of the above [1] to [11], preferably, the concentration of the quinone-based compound in the aqueous liquid to which the quinone-based compound and the chelating agent is added is as follows. Used as:
It is preferably 1 ppm or more, more preferably 2 ppm or more, further preferably 3 ppm or more, further preferably 5 ppm or more, still more preferably 7 ppm or more, still more preferably 8 ppm or more, still more preferably 9 ppm or more, still more preferably 10 ppm or more. And preferably 1400 ppm or less, more preferably 1000 ppm or less, still more preferably 500 ppm or less, still more preferably 270 ppm or less, still more preferably 200 ppm or less, still more preferably 150 ppm or less, still more preferably 100 ppm or less, still more preferably 70 ppm or less. Is 60 ppm or less, more preferably 50 ppm or less, still more preferably 40 ppm or less, still more preferably 30 ppm or less, still more preferably 20 ppm or less, still more preferably 15 ppm or less;
Or
Preferably, 1 to 1400 ppm, 1 to 1000 ppm, 1 to 500 ppm, 1 to 270 ppm, 1 to 200 ppm, 1 to 150 ppm, 1 to 100 ppm, 1 to 70 ppm, 1 to 60 ppm, 1 to 50 ppm, 1 to 40 ppm, 1 to 30 ppm. , 1-20ppm, 1-15ppm, 2-1400ppm, 2-1000ppm, 2-500ppm, 2-270ppm, 2-200ppm, 2-150ppm, 2-100ppm, 2-70ppm, 2-60ppm, 2-50ppm, 2 ~ 40ppm, 2-30ppm, 2-20ppm, 2-15ppm, 3 ~ 1400ppm, 3 ~ 1000ppm, 3 ~ 500ppm, 3 ~ 270ppm, 3 ~ 200ppm, 3 ~ 150ppm, 3 ~ 100ppm, 3 ~ 70ppm, 3 ~ 60ppm 3, 50ppm, 3-40ppm, 3-30ppm, 3-20ppm, 3-15ppm, 5-1400ppm, 5-1000ppm, 5-500ppm, 5-270ppm, 5-200ppm, 5-150ppm, 5-100ppm, 5 ~ 70ppm, 5-60ppm, 5-50ppm, 5-40ppm, 5-30ppm, 5-20ppm, 5-15ppm, 7-1400ppm, 7-1000ppm, 7-500ppm, 7-270ppm, 7-200ppm, 7-150ppm , 7-100ppm, 7-70ppm, 7-60ppm, 7-50ppm, 7-40ppm, 7-30ppm, 7-20ppm, 7-15ppm, 8-1400ppm, 8-1000ppm, 8-500ppm, 8-270ppm, 8 ~ 200ppm, 8 ~ 150ppm, 8 ~ 100ppm, 8 ~ 70ppm, 8 ~ 60ppm, 8 ~ 50ppm, 8 ~ 40ppm, 8 ~ 30ppm, 8 ~ 20ppm, 8 ~ 15ppm, 9 ~ 1400ppm, 9 ~ 1000ppm, 9 ~ 500ppm , 9-270ppm, 9-200ppm, 9-150ppm, 9-100ppm, 9-70ppm, 9-60ppm, 9-50ppm, 9-40ppm, 9-30ppm, 9-20ppm, 9-15ppm, 10-1400ppm, 10 ~ 1000ppm, 10-500ppm, 10-270ppm, 10-200ppm, 10-150ppm, 10-100ppm, 10-70ppm, 10-60ppm, 10-50ppm, 10-40ppm, 10-30ppm, 10-20ppm, or 10- 15 ppm.

[13] In any one of the above [1] to [12], preferably, the concentration of the chelating agent in the aqueous liquid to which the quinone compound and the chelating agent are added is as follows. Used for:
It is preferably 0.05 ppm or more, more preferably 0.1 ppm or more, still more preferably 0.3 ppm or more, still more preferably 0.5 ppm or more, still more preferably 1 ppm or more, still more preferably 2 ppm or more, and preferably 1000 ppm. Below, more preferably 500 ppm or less, still more preferably 100 ppm or less, still more preferably 70 ppm or less, still more preferably 50 ppm or less, still more preferably 40 ppm or less, still more preferably 30 ppm or less, still more preferably 25 ppm or less, still more preferably 20 ppm or less;
Or
Preferably, 0.05 to 1000 ppm, 0.05 to 500 ppm, 0.05 to 100 ppm, 0.05 to 70 ppm, 0.05 to 50 ppm, 0.05 to 40 ppm, 0.05 to 30 ppm, 0.05 to 25 ppm. , 0.05 to 20 ppm, 0.1 to 1000 ppm, 0.1 to 500 ppm, 0.1 to 100 ppm, 0.1 to 70 ppm, 0.1 to 50 ppm, 0.1 to 40 ppm, 0.1 to 30 ppm, 0 .1 to 25 ppm, 0.1 to 20 ppm, 0.3 to 1000 ppm, 0.3 to 500 ppm, 0.3 to 100 ppm, 0.3 to 70 ppm, 0.3 to 50 ppm, 0.3 to 40 ppm, 0.3 ~ 30ppm, 0.3 ~ 25ppm, 0.3 ~ 20ppm, 0.5 ~ 1000ppm, 0.5 ~ 500ppm, 0.5 ~ 100ppm, 0.5 ~ 70ppm, 0.5 ~ 50ppm, 0.5 ~ 40ppm , 0.5 to 30 ppm, 0.5 to 25 ppm, 0.5 to 20 ppm, 1 to 1000 ppm, 1 to 500 ppm, 1 to 100 ppm, 1 to 70 ppm, 1 to 50 ppm, 1 to 40 ppm, 1 to 30 ppm, 1 to 25 ppm. , 1-20 ppm, 2-1000 ppm, 2-500 ppm, 2-100 ppm, 2-70 ppm, 2-50 ppm, 2-40 ppm, 2-30 ppm, 2-25 ppm, or 2-20 ppm.

[14] In any one of the above [1] to [13], the concentrations of the quinone compound and the chelating agent in the aqueous liquid to which the quinone compound and the chelating agent are added are preferably 1 respectively. ~ 1400 ppm and 0.05 to 1000 ppm, more preferably 5 to 200 ppm and 0.3 to 100 ppm, still more preferably 5 to 50 ppm and 0.3 to 30 ppm, still more preferably 5 to 30 ppm and 0. It is 5 to 20 ppm.

[15] In any one of the above [1] to [14], the amount of the chelating agent used is determined.
With respect to 100 parts by mass of the quinone compound, preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, further preferably 1 part by mass or more, still more preferably 3 parts by mass or more, still more preferably 5 parts. More than parts by mass, more preferably 7 parts by mass or more, and preferably 5000 parts by mass or less, more preferably 2000 parts by mass or less, still more preferably 1000 parts by mass or less, still more preferably 700 parts by mass or less, still more preferably. Is it 500 parts by mass or less, more preferably 300 parts by mass or less;
Or
With respect to 100 parts by mass of the quinone compound, preferably 0.1 to 5000 parts by mass, 0.1 to 2000 parts by mass, 0.1 to 1000 parts by mass, 0.1 to 700 parts by mass, 0.1 to 1 parts by mass. 500 parts by mass, 0.1 to 300 parts by mass, 0.5 to 5000 parts by mass, 0.5 to 2000 parts by mass, 0.5 to 1000 parts by mass, 0.5 to 700 parts by mass, 0.5 to 500 parts by mass Parts, 0.5 to 300 parts by mass, 1 to 5000 parts by mass, 1 to 2000 parts by mass, 1 to 1000 parts by mass, 1 to 700 parts by mass, 1 to 500 parts by mass, 1 to 300 parts by mass, 3 to 5000 parts by mass 3 to 2000 parts by mass, 3 to 1000 parts by mass, 3 to 700 parts by mass, 3 to 500 parts by mass, 3 to 300 parts by mass, 5 to 5000 parts by mass, 5 to 2000 parts by mass, 5 to 1000 parts by mass, 5 to 700 parts by mass, 5 to 500 parts by mass, 5 to 300 parts by mass, 7 to 5000 parts by mass, 7 to 2000 parts by mass, 75 to 1000 parts by mass, 7 to 700 parts by mass, 7 to 500 parts by mass, or 7 ~ 300 parts by mass.

[16] In any one of the above [2] to [4] and [6] to [15], the water-based liquid is preferably the cooling water of the water-cooled cooling tower.

[17] In any one of the above [1], [2], and [8] to [16], preferably, the biofilm formation suppressing composition is a biofilm in the cooling water of a water-cooled cooling tower. It is a composition for suppressing formation.

[18] In any one of the above [1], [2], [7], and [8] to [17], the content of the quinone compound in the biofilm formation suppressing composition is as follows. Is:
It is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1% by mass or more, still more preferably 3% by mass or more, still more preferably 5% by mass or more, and preferably 90% by mass. By mass or less, more preferably 70% by mass or less, still more preferably 50% by mass or less, still more preferably 30% by mass or less, still more preferably 20% by mass or less;
Or
Preferably, 0.1 to 90% by mass, 0.1 to 70% by mass, 0.1 to 50% by mass, 0.1 to 30% by mass, 0.1 to 20% by mass, 0.5 to 90% by mass. , 0.5 to 70% by mass, 0.5 to 50% by mass, 0.5 to 30% by mass, 0.5 to 20% by mass, 1 to 90% by mass, 1 to 70% by mass, 1 to 50% by mass. , 1 to 30% by mass, 1 to 20% by mass, 3 to 90% by mass, 3 to 70% by mass, 3 to 50% by mass, 3 to 30% by mass, 3 to 20% by mass, 5 to 90% by mass, 5 ~ 70% by mass, 5 to 50% by mass, 5 to 30% by mass, or 5 to 20% by mass.

[19] In any one of the above [1], [2], [7], and [8] to [18], the content of the chelating agent in the biofilm formation suppressing composition is as follows. Is:
It is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, and preferably 90% by mass or less. More preferably 70% by mass or less, further preferably 50% by mass or less, still more preferably 30% by mass or less, still more preferably 20% by mass or less;
Or
Preferably, 0.05 to 90% by mass, 0.05 to 70% by mass, 0.05 to 50% by mass, 0.05 to 30% by mass, 0.05 to 20% by mass, 0.1 to 90% by mass. , 0.1 to 70% by mass, 0.1 to 50% by mass, 0.1 to 30% by mass, 0.1 to 20% by mass, 0.3 to 90% by mass, 0.3 to 70% by mass, 0 .3 to 50% by mass, 0.3 to 30% by mass, 0.3 to 20% by mass, 0.5 to 90% by mass, 0.5 to 70% by mass, 0.5 to 50% by mass, 0.5 ~ 30% by mass, or 0.5 to 20% by mass.

[20] In any one of the above [1], [2], [7], and [8] to [19], the content of the quinone compound and the chelating agent in the composition for suppressing biofilm formation. Are preferably 0.1 to 90% by mass and 0.05 to 90% by mass, more preferably 1 to 50% by mass and 0.1 to 50% by mass, still more preferably 1 to 20% by mass and 0. It is 3 to 30% by mass, more preferably 3 to 20% by mass and 0.3 to 30% by mass, still more preferably 5 to 20% by mass and 0.5 to 20% by mass.

[21] In any one of the above [1], [2], [7], and [8] to [20], the content of the chelating agent in the biofilm formation suppressing composition is as follows. Is:
With respect to 100 parts by mass of the quinone compound, preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, further preferably 1 part by mass or more, still more preferably 3 parts by mass or more, still more preferably 5 parts. More than parts by mass, more preferably 7 parts by mass or more, and preferably 5000 parts by mass or less, more preferably 2000 parts by mass or less, still more preferably 1000 parts by mass or less, still more preferably 700 parts by mass or less, still more preferably. 500 parts by mass or less, more preferably 300 parts by mass or less;
Or
With respect to 100 parts by mass of the quinone compound, preferably 0.1 to 5000 parts by mass, 0.1 to 2000 parts by mass, 0.1 to 1000 parts by mass, 0.1 to 700 parts by mass, 0.1 to 1 parts by mass. 500 parts by mass, 0.1 to 300 parts by mass, 0.5 to 5000 parts by mass, 0.5 to 2000 parts by mass, 0.5 to 1000 parts by mass, 0.5 to 700 parts by mass, 0.5 to 500 parts by mass Parts, 0.5 to 300 parts by mass, 1 to 5000 parts by mass, 1 to 2000 parts by mass, 1 to 1000 parts by mass, 1 to 700 parts by mass, 1 to 500 parts by mass, 1 to 300 parts by mass, 3 to 5000 parts by mass 3 to 2000 parts by mass, 3 to 1000 parts by mass, 3 to 700 parts by mass, 3 to 500 parts by mass, 3 to 300 parts by mass, 5 to 5000 parts by mass, 5 to 2000 parts by mass, 5 to 1000 parts by mass, 5 to 700 parts by mass, 5 to 500 parts by mass, 5 to 300 parts by mass, 7 to 5000 parts by mass, 7 to 2000 parts by mass, 7 to 1000 parts by mass, 7 to 700 parts by mass, 7 to 500 parts by mass, or 7 ~ 300 parts by mass.

[22] In any one of the above [1], [2], [7], and [8] to [21], the biofilm formation suppressing composition contains an organic solvent as an optional component. The amount of organic solvent in the composition is also good.
It is preferably 95% by mass or less, more preferably 93% by mass or less, and preferably 0% by mass or more, more preferably 30% by mass or more, still more preferably 50% by mass or more, still more preferably 70% by mass or more. Or preferably 0-95% by mass, 0-93% by mass, 30-95% by mass, 30-93% by mass, 50-95% by mass, 50-93% by mass, 70-95% by mass or 70- It is 93% by mass.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited thereto.

(1. Reagents and medium)
p-Turkinone (Tokyo Kasei)
Chelating agent 1-Hydroxyethane-1,1-diphosphonic acid (HEDP) (Tokyo Kasei)
Citric acid (Kishida chemistry, special grade)
Ethylenediaminetetraacetic acid (EDTA) (Dojin Chemical Laboratory)
Diethylene glycol monomethyl ether (MDG) (Wako Pure Chemicals, first grade)
R2A medium (Wako Pure Medicine)

(2. Biofilm suppression test)
(2-1. Preparation of test bacteria)
Biofilm-forming bacteria isolated from cooling water collected from a water-cooled cooling tower (bacteria having an OD570 of 0.3 or more in the measurement test for the amount of biofilm in 2-4 below) were used in R2A medium at 30 ° C. for 16 hours. It was cultured with shaking. The turbidity (OD600) of the obtained culture solution was measured and diluted with R2A medium to prepare a suspension of 10 ³ cfu / mL.

(2-2. Preparation of composition for suppressing biofilm formation)
A predetermined amount of p-torquinone and HEDP were weighed and a solvent (MDG) was added to prepare a composition. Since citric acid and EDTA were not dissolved in MDG, they were added directly to the culture solution, and p-torquinone was also added directly to the culture solution. The composition of each composition is shown in Table 1.

(2-3. Culture)
After adding 150 μL of the suspension of the test bacteria prepared in (2-1) above to each well of the 96-well microplate, the test solution prepared in (2-2) above was added to start culturing.

(2-4. Measurement of biofilm amount)
The 96-well microplate was statically cultured at 30 ° C. for 48 hours, and then the culture solution was removed and washed with water. Subsequently, each well was stained with 0.1% crystal violet, 200 μL of ethanol was added, and the absorbance (OD570) was measured to determine the amount of biofilm (BF) formed.

(2-5. Results and discussion)
The results of the BF suppression test are shown in Tables 2-4. Comparing Experiment Nos. 2 and 5-8, it was shown that the combined use of HEDP and p-torquinone enhances the BF inhibitory effect as compared with p-torquinone alone. Comparing Experiment Nos. 12 and 15-18, it was shown that the combined use of citric acid and p-torquinone enhances the BF inhibitory effect as compared with p-torquinone alone. Comparing Experiment Nos. 21 with 24-26, it was shown that the combined use of EDTA and p-tolucinone increased the BF inhibitory effect as compared with p-tolucinone alone. Compared with EDTA, HEDP and citric acid showed a BF inhibitory effect at lower concentrations.

Claims (8)

It contains a quinone compound and a chelating agent , and the quinone compound is p-tolucinone, and the chelating agent is selected from the group consisting of 1-hydroxyethane-1,1-diphosphonic acid, citric acid and ethylenediaminetetraacetic acid. Ru der 1 or more, biofilm formation inhibition composition. To the quinone compound 100 parts by weight, containing the chelating agent from 0.1 to 5000 parts by weight, claim 1 biofilm inhibiting composition according. The composition for suppressing biofilm formation according to claim 1 or 2 , which is a composition for suppressing biofilm formation in the cooling water of a water-cooled cooling tower. A quinone compound and a chelating agent saw including adding to the aqueous liquid, said quinone compound is p- toluquinone, the chelating agent is 1-hydroxyethane-1,1-diphosphonic acid, citric acid and ethylenediamine tetraacetic A method for suppressing biofilm formation, which is one or more selected from the group consisting of acetic acid . The method according to claim 4 , wherein 0.1 to 5000 parts by mass of the chelating agent is added to the aqueous liquid with respect to 100 parts by mass of the quinone compound. Claim 4 or 5 in which the quinone compound is added to the aqueous liquid so that the concentration of the quinone compound in the aqueous liquid to which the quinone compound and the chelating agent are added is 1 to 1400 ppm. Item description method. Claims 4 to 6 such that the chelating agent is added to the aqueous liquid so that the concentration of the chelating agent in the aqueous liquid to which the quinone compound and the chelating agent are added is 0.05 to 1000 ppm. The method according to any one of the above. The method according to any one of claims 4 to 7 , wherein the water-based liquid is cooling water for a water-cooled cooling tower.