PFAS reduction method, method for producing liquid having reduced PFAS concentration, and PFAS reducing agent

Abstract

The present invention addresses the problem of providing a new PFAS reduction method.　The present invention provides a PFAS reduction method including a contact step for bringing microorganisms into contact with a PFAS-containing solution, the microorganisms including the dried product of a unicellular organism or the dried product of a colony of unicellular organisms.

Description

Method for reducing PFAS, method for producing a liquid with reduced PFAS concentration, and PFAS reducing agent

[0001] This invention relates to a method for reducing PFAS, a method for producing a liquid with reduced PFAS concentration, and a PFAS reducing agent.

[0002] Perfluoroalkyl compounds and polyfluoroalkyl compounds (collectively referred to as "PFAS") are highly stable substances used in a variety of products.

[0003] On the other hand, PFAS is considered a problematic environmental pollutant due to its high persistence in the environment, and the need for PFAS removal technology is increasing. For example, Patent Document 1 proposes activated carbon for treatment that has excellent adsorption performance for PFAS.

[0004] Patent No. 7427849

[0005] However, there is still a need for PFAS removal technology.

[0006] This invention has been made in view of the above circumstances, and aims to provide a novel method for reducing PFAS.

[0007] The inventors have discovered a novel finding that certain microorganisms exhibit a good PFAS reduction effect, and have completed the present invention. Specifically, the present invention provides the following:

[0008] (1) A method for reducing PFAS, wherein the reduction method includes a contact step of bringing a microorganism into contact with a PFAS-containing solution, and the microorganism includes a dried single-celled organism or a dried colony of a single-celled organism.

[0009] (2) The reduction method according to (1), wherein the microorganism is a microalga.

[0010] (3) The microorganism is Anabaena flos-aquae, Chlamydomonas reinhardtii, Chlorella vulgaris, Parachlorella genus Parachlorella kessleri, Navicula genus Navicula pelliculosa, Scenedesmus genus Scenedesmus obliquus, Porphyridium cruentum, Nannochloropsis oculate, The reduction method according to (1) or (2), comprising one or more selected from the group consisting of Cyanidium caldarium of the genus Cyanidium and Phaeodactylum tricornutum of the genus Phaeodactylum.

[0011] (4) The reduction method according to any one of (1) to (3), wherein the PFAS includes one or more selected from the group consisting of PFOS, PFOA, and PFHxS.

[0012] (5) A reduction method according to any one of (1) to (4), further comprising a step of separating the microorganism after the contact step.

[0013] (6) A method for producing a liquid with reduced PFAS concentration, wherein the method includes a contact step of bringing a microorganism into contact with a PFAS-containing solution, and the microorganism includes a dried single-celled organism or a dried colony of a single-celled organism.

[0014] (7) The microorganism is Anabaena flos-aquae, Chlamydomonas reinhardtii, Chlorella vulgaris, Parachlorella genus Parachlorella kessleri, Navicula genus Navicula pelliculosa, Scenedesmus genus Scenedesmus obliquus, Porphyridium cruentum, Nannochloropsis oculate, The manufacturing method according to (6), comprising one or more selected from the group consisting of Cyanidium caldarium of the genus Cyanidium and Phaeodactylum tricornutum of the genus Phaeodactylum.

[0015] (8) The manufacturing method according to (6) or (7), wherein the PFAS comprises one or more selected from the group consisting of PFOS, PFOA, and PFHxS.

[0016] (9) A PFAS reducing agent, wherein the reducing agent includes a dried single-celled organism or a dried colony of a single-celled organism.

[0017] (10) The unicellular organism is Anabaena flos-aquae of the genus Anabaena, Chlamydomonas reinhardtii of the genus Chlamydomonas, Chlorella vulgaris of the genus Chlorella, Parachlorella genus Parachlorella kessleri, Navicula genus Navicula pelliculosa, Scenedesmus genus Scenedesmus obliquus, Porphyridium cruentum, Nannochloropsis The reducing agent according to (9), comprising one or more selected from the group consisting of oculate, Cyanidium caldarium of the genus Cyanidium, and Phaeodactylum tricornutum of the genus Phaeodactylum.

[0018] (11) The reducing agent according to (9) or (10), wherein the PFAS comprises one or more selected from the group consisting of PFOS, PFOA, and PFHxS.

[0019] The present invention provides a novel method for reducing PFAS.

[0020] This figure shows the effect of the microorganisms used in the examples on reducing PFAS (PFOS). This figure shows the effect of the microorganisms used in the examples on reducing PFAS (PFOA). This figure shows the effect of the microorganisms used in the examples on reducing PFAS (PFHxS).

[0021] The following describes specific embodiments of the present invention in detail, but the present invention is not limited to the following embodiments.

[0022] <Method for Reducing PFAS> The method for reducing PFAS according to the present invention (hereinafter also referred to as "the reduction method of the present invention") satisfies the following requirements in one embodiment: - The reduction method includes a contact step of bringing microorganisms into contact with a PFAS-containing solution. - The microorganisms include dried single-celled organisms or dried colonies of single-celled organisms.

[0023] As mentioned above, PFAS is considered a problematic environmental pollutant due to its high persistence in the environment, and the need for PFAS removal technology is increasing. In light of this need, the inventors focused on technology utilizing microorganisms. As a result, they discovered the unexpected finding that when the above microorganisms are brought into contact with a PFAS-containing solution, the PFAS concentration in the solution is reduced. Although the reason is not clear, it is presumed that these microorganisms have properties such as adsorbing PFAS into their bodies or on their surfaces.

[0024] Furthermore, single-celled organisms or their dried products have distribution advantages, such as being easy to transport and store. Dried microorganisms are usually dead microorganisms (dead cells), and in this embodiment, even if the microorganisms are recombinants, dried microorganisms can be used technically without being subject to the Cartagena Protocol by coming into contact with PFAS-containing solutions in the natural environment. In addition, dried microorganisms are usually dead microorganisms (dead cells), and are unlikely to affect the ecosystems of organisms living in existing natural environments (e.g., rivers, lakes, seas, etc.).

[0025] In the present invention, "reduction of PFAS" includes the decrease in the PFAS concentration in the resulting solution when microorganisms are brought into contact with a PFAS-containing solution, compared to the concentration before contact. "Decrease in PFAS concentration" includes not only a decrease in PFAS concentration compared to the concentration before contact, but also the fact that PFAS becomes undetectable after contact.

[0026] The PFAS concentration in the solution can be determined by high-performance liquid chromatography. The conditions for high-performance liquid chromatography can be those shown in the examples.

[0027] The reduction method of the present invention will be described in detail below.

[0028] (1) Contact process In the contact process, microorganisms and a PFAS-containing solution are brought into contact under arbitrary conditions. This process reduces the PFAS concentration in the solution (a mixture of microorganisms and the PFAS-containing solution).

[0029] (1-1) Microorganisms The microorganisms in the present invention are not particularly limited as long as they are in the form of dried single-celled organisms or dried colonies of single-celled organisms.

[0030] In the present invention, "dried single-celled organism" and "dried colony of single-celled organism" include single-celled organisms or their colonies that have been dried by any method. The drying method is not particularly limited as long as it can reduce the moisture content of the single-celled organism or its colony, but examples include natural drying, freeze-drying, and hot-air drying.

[0031] The form of the dried single-celled organism or its colony is not particularly limited, and examples include dried single-celled organisms or their colonies that retain their shape, or crushed or powdered single-celled organisms or their colonies.

[0032] The particle size of dried single-celled organisms or their colonies is not particularly limited. The particle size of dried single-celled organisms is usually between 1 μm and 1 mm. The preferred lower limit for the particle size of dried single-celled organism colonies is between 1 μm and 1 mm, 10 mm and 100 mm and 100 mm. The preferred upper limit for the particle size of dried single-celled organism colonies is between 1 mm and 10 mm and 100 mm and 500 mm and 500 mm.

[0033] The method for measuring the particle size of a dried single-celled organism or its colony is not particularly limited, but it is preferably determined by an electrical method based on the Coulter principle. However, depending on the shape of the dried single-celled organism or its colony, the above method based on the Coulter principle may not be suitable (for example, if the dried material is long and thread-like). In such cases, the particle size may be determined by visual measurement using a microscope.

[0034] The water content of the dried product of unicellular organisms or their colonies is not particularly limited. The preferable lower limit of the water content of the dried product of unicellular organisms or their colonies is 40% by mass or more, 30% by mass or more, 20% by mass or more, 15% by mass or more, 10% by mass or more, 5% by mass or more, 4% by mass or more, 3% by mass or more, 2% by mass or more, 1% by mass or more, 0.5% by mass or more, 0.1% by mass or more, 0.01% by mass or more. The preferable upper limit of the water content of the dried product of unicellular organisms or their colonies is 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, 2% by mass or less, 1% by mass or less, 0.5% by mass or less, 0.1% by mass or less, 0.01% by mass or less.

[0035] The method for measuring the water content of the dried product of unicellular organisms or their colonies is not particularly limited, but is preferably specified by the drying loss method. In a typical example of the drying loss method, the water content is specified based on the following formula. Water content (% by mass) = (A - B) × 100 / (A - C) A: Mass including the weighing bottle before drying (g) B: Mass including the weighing bottle after drying (g) C: Mass of the used weighing bottle (g)

[0036] The drying method for obtaining the dried product of unicellular organisms or their colonies is not particularly limited, and examples include hot air drying, vacuum drying, steam drying, barrel drying, spin drying, suction drying, freeze drying, etc. The microorganisms contained in such dried products are usually dead microorganisms (dead cells). However, the aspect in which the dried product contains viable microorganisms (living cells) is not excluded from the present invention.

[0037] In one aspect of the present invention, as the microorganism, any microorganism classified as microalgae can be used. Examples of microalgae include marine microalgae and freshwater microalgae. Examples of microalgae include cyanobacteria, prokaryotic green algae, red algae, gray algae, cryptophytes, dinoflagellates, golden algae, brown algae, yellow-green algae, haptophytes, raphidophytes (green flagellates), Chlorarachniophyceae, Euglenophyceae (Euglena), Prasinophyceae, Chlorophyceae, Trebouxia, Eustigmatophyceae, Dictyochophyceae, Pelagophyceae, and Charophyceae.

[0038] In one embodiment of the present invention, the microorganism comprises one or more selected from the group consisting of the genera Anabaena (cyanobacteria), Chlamydomonas (green algae), Chlorella (green algae), Parachlorella (green algae), Navicula (diatoms), Scenedesmus (green algae), Porphyridium (red algae), Nannochloropsis (eyespot algae), Cyanidium (red algae), and Phaeodactylum (diatoms). The microorganism may be used individually or in combination of two or more species. All of the above microorganisms are selected from single-celled organisms. All of the above microorganisms are classified as microalgae.

[0039] Algae are a general term for organisms that perform oxygen-producing photosynthesis, excluding mosses, ferns, and seed plants that mainly inhabit land. This includes cyanobacteria (blue-green algae), which are true bacteria, as well as eukaryotic single-celled organisms (diatoms, yellow-green algae, dinoflagellates, etc.) and multicellular organisms such as seaweed (red algae, brown algae, green algae). Photosynthetic bacteria, such as sulfur bacteria, which perform non-oxygen-producing photosynthesis, are not included in algae. Microalgae (or microphyltes) are phytoplankton found in freshwater, seawater, and sediments, and are typically 1 mm to 1 μm in size. The morphology of microalgae is not particularly limited, but examples include single-celled organisms and colonies formed by the adhesion of single-celled organisms. Microalgae are usually capable of photosynthesis and produce about half of the oxygen in the Earth's atmosphere. Microalgae form the basis of the food chain in aquatic ecosystems, supplying nutrients to higher-level organisms. The biomass of microalgae is measured by the concentration of chlorophyll a. Microalgae include mutants resulting from spontaneous mutations and genetically modified organisms obtained through genetic engineering techniques. Methods for obtaining spontaneously occurring mutants include heavy ion beam irradiation, while methods for obtaining genetically modified organisms include recombination techniques using CRISPR-Cas9, etc.

[0040] Examples of microorganisms of the genus Anabaena include Anabaena flos-aquae and the like.

[0041] Examples of microorganisms of the genus Chlamydomonas include Chlamydomonas reinhardtii and the like.

[0042] Examples of microorganisms of the genus Chlorella include Chlorella vulgaris and the like.

[0043] Examples of microorganisms of the genus Parachlorella include Parachlorella kessleri and the like.

[0044] Examples of microorganisms of the genus Navicula include Navicula pelliculosa and the like.

[0045] Examples of microorganisms of the genus Scenedesmus include Scenedesmus obliquus and the like.

[0046] Examples of microorganisms of the genus Porphyridium include Porphyridium cruentum and the like.

[0047] Examples of microorganisms of the genus Nannochloropsis include Nannochloropsis oculata and the like.

[0048] Examples of microorganisms of the genus Cyanidium include Cyanidium caldarium and the like.

[0049] Examples of microorganisms of the genus Phaeodactylum include Phaeodactylum tricornutum and the like.

[0050] In a preferred embodiment of the present invention, the microorganisms are Anabaena flos-aquae, Chlamydomonas reinhardtii, Chlorella vulgaris, Parachlorella kessleri, Navicula pelliculosa, Scenedesmus obliquus, Porphyridium creuentum, Nannochloropsis oculate, It contains one or more microorganisms selected from the group consisting of Cyanidium caldarium of the genus Cyanidium and Phaeodactylum tricornutum of the genus Phaeodactylum. These microorganisms can particularly stably reduce PFAS concentration.

[0051] (1-2) PFAS-containing solution A PFAS-containing solution is a target for which the PFAS concentration is to be reduced by the action of microorganisms.

[0052] In the present invention, "PFAS" includes any perfluoroalkyl compound and any polyfluoroalkyl compound. The compounds constituting PFAS may be one or more.

[0053] In one embodiment of the present invention, PFAS comprises one or more selected from the group consisting of PFOS, PFOA, and PFHxS.

[0054] PFOS stands for "Perfluorooctanesulfonic acid" (CAS registration number: 1763-23-1, chemical formula: C ８ HF １７ O ３ It is an abbreviation for S.

[0055] PFOA stands for "perfluorooctanoic acid" (CAS registration number: 335-67-1, chemical formula: C ８ HF １５ O ２ It is an abbreviation for ).

[0056] PFHxS is an abbreviation of "perfluorohexanesulfone" (CAS registration number: 355-46-4, chemical formula: C ６ HF １３ O ３ S).

[0057] The solvent of the PFAS-containing solution is not particularly limited and includes any solvent in which PFAS can be present. Examples include water (tap water, seawater, etc.), media for microorganism culture, etc. Examples of media for microorganism culture include those shown in the examples (BG-11 medium, TAP medium). The BG-11 medium is an example of a preferred medium for microorganism culture in the genus Anabaena, and the TAP medium is an example of a preferred medium for microorganism culture in the genus Chlamydomonas.

[0058] In the present invention, the "PFAS-containing solution" includes not only a solution known to contain PFAS but also a solution suspected of containing PFAS.

[0059] In one aspect of the present invention, the PFAS-containing solution is not particularly limited, but is wastewater, fresh water, brackish water, or seawater. For example, a solution suspected of containing PFAS (a solution whose actual PFAS content is unknown) may be subjected to the reduction method of the present invention. Examples of wastewater include industrial wastewater, etc. Examples of fresh water include river water, lake water, groundwater, tap water. Examples of brackish water include river water, lake water, coastal water. Examples of seawater include those mainly composed of water and containing about 3.5% by mass of salt and trace metals. Specifically, seawater, artificial seawater, etc. are included.

[0060] The temperature, turbidity, viscosity, etc. of a solution suspected of containing PFAS are not particularly limited as long as they are conditions under which microorganisms can grow.

[0061] The PFAS concentration in the PFAS-containing solution used in the reduction method of the present invention (the solution before contact with microorganisms in the present invention) is not particularly limited. From the viewpoint of easily achieving the effects of the present invention, the preferred lower limit of the PFAS concentration in the PFAS-containing solution is greater than 0, 0.00001 mg / L or more, 0.001 mg / L or more, 0.01 mg / L or more, 0.05 mg / L or more, 0.5 mg / L or more, 0.1 mg / L or more, 0.5 mg / L or more, 1 mg / L or more, 5 mg / L or more, and 10 mg / L or more. From the viewpoint of easily achieving the effects of the present invention, the preferred upper limit of the PFAS concentration in the PFAS-containing solution is 0.00001 mg / L or less, 0.001 mg / L or less, 0.01 mg / L or less, 0.05 mg / L or less, 0.5 mg / L or less, 0.1 mg / L or less, 0.5 mg / L or less, 1 mg / L or less, 5 mg / L or less, and 10 mg / L or less. From the viewpoint of easily achieving the effects of the present invention, the PFAS concentration in the PFAS-containing solution is preferably 0.001 mg / L or more and 0.5 mg / L or less, more preferably 0.01 mg / L or more and 0.1 mg / L or less, and even more preferably 0.05 mg / L or more and 0.5 mg / L or less.

[0062] (1-3) Contact conditions: The microorganisms are placed in the same container (culture tank, etc.) as the PFAS-containing solution. By mixing the microorganisms into the PFAS-containing solution in this manner, the microorganisms can be brought into contact with the PFAS-containing solution.

[0063] The amount and ratio of microorganisms and PFAS-containing solutions used in the contact process are not particularly limited and can be set appropriately according to the degree of effect to be obtained.

[0064] From the viewpoint of ensuring that the effects of the present invention are stably achieved, the amount of microorganisms subjected to the contact process may be adjusted so that the solution at the start of contact has an OD (Optical Density) of 0.05 to 0.5.

[0065] Since the dried material subjected to the contact process is usually composed almost entirely of dead cells, the conditions of the contact process are not particularly limited. In a preferred embodiment, the contact process is carried out under conditions in which the dried material is easily dispersed, such as in the presence of a low-viscosity medium or a solvent that does not easily foam. Therefore, the contact process may be under culture conditions in which living cells can grow, or under culture conditions in which living cells cannot grow.

[0066] Examples of culture conditions that allow living cells to grow include: • Culture under aeration (e.g., circulating 1-3% carbon dioxide into the container) • Culture under light conditions (e.g., setting the light intensity inside the container to 20-70 μmol / m²) ２ (Set to / s) ・Cultivation at a temperature that does not inhibit the growth of microorganisms (for example, 5.0°C or higher, 10.0°C or higher, 15.0°C or higher, 20.0°C or higher, 25.0°C or higher, 30.0°C or higher, 10.0°C or lower, 15.0°C or lower, 20.0°C or lower, 25.0°C or lower, 30.0°C or lower, 35.0°C or lower, 40.0°C or lower. Preferably, from the viewpoint of microbial growth and the cost of temperature control, 10.0°C or higher and 30.0°C or lower, 15.0°C or higher and 30.0°C or lower, 20.0°C or higher and 25.0°C or lower.)

[0067] Examples of culture conditions that make it difficult for living cells to grow include: • Culture in an unaerated environment • Culture in the dark • Culture at temperatures that inhibit microbial growth (e.g., below 5°C, above 40°C)

[0068] The contact time in the contact process is not particularly limited and can be adjusted according to the desired PFAS reduction effect. In one embodiment of the present invention, from the viewpoint of obtaining a sufficient PFAS reduction effect, the preferred lower limit of the contact time (total time) is 1 hour or more, 1 day or more, 2 days or more, 3 days or more, 5 days or more, 7 days or more, 10 days or more, 14 days or more, 20 days or more, and 30 days or more. In one embodiment of the present invention, from the viewpoint of obtaining a sufficient PFAS reduction effect, the preferred upper limit of the culture time (total time) is 1 day or less, 2 days or less, 3 days or less, 5 days or less, 7 days or less, 10 days or less, 14 days or less, 20 days or less, 30 days or less, and 60 days or less. In one embodiment of the present invention, the culture time (total time) is preferably 5 days or more and 30 days or less, more preferably 7 days or more and 14 days or less, and even more preferably 10 days or more and 14 days or less.

[0069] (2) Separation step After the contact step is completed, a step of separating microorganisms from the solution (hereinafter also referred to as the "separation step") may be provided. This step allows PFAS to be removed from the solution along with the microorganisms, thereby reducing the concentration of PFAS in the solution.

[0070] The method for separating microorganisms from a solution in the separation process is not particularly limited, but examples include centrifugation, filtration, and natural precipitation. By removing solid matter from the solution through such a process, microorganisms can be separated from the solution.

[0071] The solution from which microorganisms (solid matter) have been separated can be used for any purpose as a liquid with reduced PFAS concentration.

[0072] <Method for producing a liquid with reduced PFAS concentration> The present invention also includes a method for producing a liquid with reduced PFAS concentration (hereinafter also referred to as "the manufacturing method of the present invention").

[0073] In one embodiment, the manufacturing method of the present invention satisfies the following requirements: • The manufacturing method includes a contact step of bringing a microorganism into contact with a PFAS-containing solution. • The microorganism includes a dried single-celled organism or a dried colony of a single-celled organism.

[0074] Each component in the manufacturing method of the present invention can be appropriately adopted from those in the reduction method of the present invention.

[0075] In one embodiment of the present invention, the liquid obtained by the manufacturing method of the present invention corresponds to the solution obtained after the separation step in the reduction method of the present invention. Such a solution is one form of a "liquid with reduced PFAS concentration".

[0076] <PFAS Reducing Agent> The present invention also includes a PFAS reducing agent (hereinafter also referred to as "the agent of the present invention") which includes a dried single-celled organism or a dried colony of a single-celled organism.

[0077] Each component of the agent of the present invention can be appropriately adopted from those used in the reduction method of the present invention.

[0078] The agent of the present invention may consist of a dried single-celled organism or its colony, and may also contain other components (such as excipients) to the extent that they do not inhibit the effects of the present invention. When other components are included, it is preferable to include dried components, as it is desirable to maintain the dry state of the dried single-celled organism or its colony.

[0079] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0080] <Test 1> The following method was used to bring a PFAS-containing solution into contact with microorganisms and examine the effect on PFAS concentration.

[0081] (1) Preparation of Microorganisms In this example, one of the following seven types of microorganisms (algal strains) obtained from UTEX (The Culture Collection of Algae at the University of Texas) was used.・"UTEX 1444": Anabaena flos-aquae UTEX 1444 stocks ・"UTEX 90": Chlamydomonas reinhardtii UTEX 90 stocks ・"UTEX 161": Porphyridium cruentum UTEX 161 stocks / "UTEX 30": Chlorella vulgaris UTEX 30 stocks / "UTEX 2164": Nannochloropsis oculate UTEX 2164 stocks / "UTEX 2393": Cyanidium caldarium UTEX 2393 shares / "UTEX 642": Phaeodactylum tricornutum UTEX 642 shares

[0082] (2) Treatment of microorganisms The above microorganisms were treated by the following method to obtain dried microorganisms (corresponding to dried single-celled organisms or dried colonies of single-celled organisms).

[0083] BG-11 medium (50 mL) was prepared as the culture medium for "UTEX 1444". TAP medium (50 mL) was prepared as the culture medium for "UTEX 90". TAP medium (50 mL) was prepared as the culture medium for "UTEX 30". BG-11 + artificial seawater medium (50 mL) was prepared as the culture medium for "UTEX 161", "UTEX 2164", and "UTEX 642". Allen medium (50 mL) was prepared as the culture medium for "UTEX 2393".

[0084] The composition of BG-11 medium is as follows:

[0085]

[0086] The composition of the TAP medium is as follows:

[0087]

[0088] The composition of Allen medium is as follows:

[0089]

[0090] Microorganisms corresponding to the type of culture medium were inoculated so that the OD (Optical Density) 750 = 0.1. Then, 2% CO2 was added. ２ With air permeable, the light intensity was 40 μmol / m². ２ The culture was incubated with air for 14 days at / s. After the culture was complete, the culture was freeze-dried to obtain a dried microbial product (dried powder). Almost all of the microorganisms contained in this dried product were dead cells.

[0091] (3) Contact between microorganisms and PFAS-containing solutions The dried product of each microorganism was contacted with one of the following three types of PFAS: ・PFOS (Compound name: Perfluorooctane sulfonic acid, manufactured by AccuStandard) ・PFOA (Compound name: Perfluorooctanoic acid, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) ・PFHxS (Compound name: Perfluorohexane sulfonic acid, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

[0092] The dried product of each microorganism was brought into contact with PFAS as follows. Each dried product was suspended in culture medium (50 mL). The amounts of dried product of each microorganism used were as follows: • UTEX 1444: 42 mg • UTEX 90: 62 mg • UTEX 161: 405 mg • UTEX 30: 84 mg • UTEX 2164: 104 mg • UTEX 2393: 46 mg • UTEX 642: 105 mg

[0093] Next, one of the three PFAS-containing solutions (2 μg / mL each, methanol solution, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to the resulting suspension to a final concentration of 40,000 ng / L. After addition, 2% CO2 ２ With air permeable, the light intensity was 40 μmol / m². ２Aeration was performed at a rate of / s for 14 days. Simultaneously, a PFAS-containing solution (blank) was aerated under the same conditions as above, except that no microorganisms were inoculated. After aeration was completed, the solutions were collected, diluted fourfold with water, and the PFAS concentration was measured. Based on the measurement results, the PFAS concentration in the 14-day aerated sample in the presence of dried material of each microorganism was calculated as a relative value to the 14-day aerated sample of the same type of blank.

[0094] PFAS concentration was measured by high-performance liquid chromatography (LC / MS-MS) under the following conditions, based on the JIS official method (JIS K 0450-20-10:2011): • Instrument: Liquid chromatograph-mass spectrometer (Agilent Technology, LC section: 1260 Infinity II, MS section: 6470 LC / TQ) • Mobile phase: 0.5 mM ammonium acetate aqueous solution of acetonitrile • Columns used: Delay column: "Delay Column for PFAS" (GL Sciences Co., Ltd.), Separation column: "Inert sustain C18" (GL Sciences) • Flow rate: 0.2 mL / min • Column temperature: 40°C • Detector: "6470 LC / TQ" (Agilent Technology)

[0095] (4) Results The results regarding PFAS concentration are shown in Figures 1 to 3. In each figure, the vertical axis shows the relative value of the PFAS concentration when the blank is set to "100%", and a lower value means that the PFAS reduction effect is higher. As shown in Figures 1 to 3, it was found that each of the microorganisms used in this example has a PFAS reduction effect.

Claims

1. A method for reducing PFAS, wherein the reduction method includes a contact step of bringing a microorganism into contact with a PFAS-containing solution, and the microorganism includes a dried single-celled organism or a dried colony of a single-celled organism.

2. The reduction method according to claim 1, wherein the microorganism is a microalga.

3. The microorganism is Anabaena flos-aquae, Chlamydomonas reinhardtii, Chlorella vulgaris, Parachlorella genus Parachlorella kessleri, Navicula genus Navicula pelliculosa, Scenedesmus genus Scenedesmus obliquus, Porphyridium cruentum, Nannochloropsis oculate, The reduction method according to claim 1, comprising one or more selected from the group consisting of Cyanidium caldarium of the genus Cyanidium and Phaeodactylum tricornutum of the genus Phaeodactylum.

4. The reduction method according to claim 1, wherein the PFAS includes one or more selected from the group consisting of PFOS, PFOA, and PFHxS.

5. A reduction method according to any one of claims 1 to 4, further comprising a step of separating the microorganism after the contact step.

6. A method for producing a liquid with reduced PFAS concentration, wherein the method includes a contact step of bringing a microorganism into contact with a PFAS-containing solution, and the microorganism includes a dried single-celled organism or a dried colony of a single-celled organism.

7. The microorganism is Anabaena flos-aquae, Chlamydomonas reinhardtii, Chlorella vulgaris, Parachlorella genus Parachlorella kessleri, Navicula genus Navicula pelliculosa, Scenedesmus genus Scenedesmus obliquus, Porphyridium cruentum, Nannochloropsis oculate, The manufacturing method according to claim 6, comprising one or more selected from the group consisting of Cyanidium caldarium of the genus Cyanidium and Phaeodactylum tricornutum of the genus Phaeodactylum.

8. The manufacturing method according to claim 6 or 7, wherein the PFAS comprises one or more selected from the group consisting of PFOS, PFOA, and PFHxS.

9. A PFAS reducing agent, wherein the reducing agent includes a dried single-celled organism or a dried colony of a single-celled organism.

10. The unicellular organism is Anabaena flos-aquae, Chlamydomonas reinhardtii, Chlorella vulgaris, Parachlorella genus Parachlorella kessleri, Navicula genus Navicula pelliculosa, Scenedesmus genus Scenedesmus obliquus, Porphyridium cruentum, Nannochloropsis The reducing agent according to claim 9, comprising one or more selected from the group consisting of oculate, Cyanidium caldarium of the genus Cyanidium, and Phaeodactylum tricornutum of the genus Phaeodactylum.

11. The reducing agent according to claim 9 or 10, wherein the PFAS comprises one or more selected from the group consisting of PFOS, PFOA, and PFHxS.

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