Method for decomposing polyvinyl alcohols and microorganisms capable of decomposing polyvinyl alcohol

Abstract

To provide technologies for decomposing polyvinyl alcohols using marine polyvinyl alcohol-decomposing microorganisms.SOLUTION: A method for degrading polyvinyl alcohols comprises: bringing polyvinyl alcohols into contact with one or more microorganisms selected from: a microorganism that belongs to the genus Leisingera, has a 16S rRNA gene composed of a nucleotide sequence showing 80% or more sequence identity with the nucleotide sequence of SEQ ID NO: 1, and has polyvinyl alcohol-decomposition ability; a microorganism that belongs to the genus Cellulophaga, has a 16S rRNA gene composed of a nucleotide sequence showing 80% or more sequence identity with the nucleotide sequence of SEQ ID NO: 2, and has polyvinyl alcohol-decomposition ability; and a microorganism that belongs to the genus Vibrio, has a 16S rRNA gene composed of a nucleotide sequence showing 80% or more sequence identity with the nucleotide sequence of SEQ ID NO: 3, and has polyvinyl alcohol-decomposition ability, and / or processed bacterial cells thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for decomposing polyvinyl alcohols, a microorganism having polyvinyl alcohol-decomposing ability, a culture supernatant and treated cells of the microorganism, a polyvinyl alcohol-decomposing enzyme derived from the microorganism, and a resin composition containing them. More specifically, the present invention relates to a method for decomposing polyvinyl alcohols using a marine polyvinyl alcohol-decomposing microorganism. [Background technology]

[0002] Concerns about marine pollution caused by microplastics have once again raised the importance of addressing the issue of environmental pollution caused by plastic waste, and there is a need to develop technologies for decomposing and recycling plastic waste.

[0003] In relation to the present invention, for example, Patent Document 1 proposes a method for decomposing polyvinyl alcohol, which comprises contacting microbacteria of the genus Microbacterium with polyvinyl alcohol. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-042612 Summary of the Invention [Problem to be solved by the invention]

[0005] A main object of the present invention is to provide a technology for decomposing polyvinyl alcohols using marine polyvinyl alcohol-decomposing microorganisms. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides the following [1]-

[16] . [1] A microorganism belonging to the genus Leisingera, having a 16S rRNA gene consisting of a base sequence showing 80% or more sequence identity with the base sequence of SEQ ID NO: 1, and having the ability to decompose polyvinyl alcohol; A microorganism belonging to the genus Cellulophaga, having a 16S rRNA gene consisting of a base sequence showing 80% or more sequence identity with the base sequence of SEQ ID NO: 2, and having the ability to decompose polyvinyl alcohol; and A microorganism belonging to the genus Vibrio, having a 16S rRNA gene consisting of a base sequence showing 80% or more sequence identity with the base sequence of SEQ ID NO: 3, and having the ability to decompose polyvinyl alcohol; A method for decomposing polyvinyl alcohols, comprising a step of contacting polyvinyl alcohols with one or more microorganisms selected from the group consisting of: [2] The microorganism belonging to the genus Leisingera belongs to Leisingera caerulea, the microorganism belonging to the genus Cellulophaga belongs to Cellulophaga lytica, The decomposition method according to [1], wherein the microorganism belonging to the genus Vibrio belongs to Vibrio alginolyticus. [3] The microorganism belonging to Leisingera caerulea is Leisingera caerulea PA2 strain, the microorganism belonging to Cellulophaga lytica is the Cellulophaga lytica PA0 strain, The decomposition method according to [2], wherein the microorganism belonging to the genus Vibrio alginolyticus is the Vibrio alginolyticus SSW-PVOH1 strain. [4] The decomposition method according to any one of [1] to [3], wherein the step is carried out in seawater. [5] The decomposition method according to any one of [1] to [3], wherein the step is carried out in the presence of 3% by weight or more of NaCl.

[0007] [6] Leisingera caerulea PA2 strain (Accession number: NITE ABP-03432). [7] A microorganism belonging to the genus Leisingera, preferably Leisingera caerulea, having a 16S rRNA gene consisting of a base sequence that shows 80% or more sequence identity with the base sequence of SEQ ID NO: 1, and having the ability to decompose polyvinyl alcohol. [8] Cellulophaga lytica PA0 strain (received number: NITE ABP-03433). [9] A microorganism belonging to the genus Cellulophaga, preferably Cellulophaga lytica, having a 16S rRNA gene consisting of a base sequence that shows 80% or more sequence identity with the base sequence of SEQ ID NO: 2, and having the ability to decompose polyvinyl alcohol.

[10] Vibrio alginolyticus SSW-PVOH1 strain (received number: NITE ABP-03434).

[11] A microorganism belonging to the genus Vibrio, preferably Vibrio alginolyticus, having a 16S rRNA gene consisting of a base sequence that shows 80% or more sequence identity with the base sequence of SEQ ID NO: 3, and having the ability to decompose polyvinyl alcohol.

[12] A culture supernatant or a treated cell product of any of the microorganisms [6]-

[11] .

[13] A polyvinyl alcohol-degrading enzyme derived from any of the microorganisms listed in [6]-

[11] .

[14] A nucleic acid encoding the enzyme of

[13] , an expression vector containing the nucleic acid, or a recombinant microorganism expressing the enzyme.

[15] A resin composition containing the culture supernatant or treated bacterial cell product of

[12] and / or the enzyme of

[13] , and polyvinyl alcohols.

[0008]

[16] A microorganism belonging to the genus Leisingera, having a 16S rRNA gene consisting of a base sequence showing 80% or more sequence identity with the base sequence of SEQ ID NO: 1, and having the ability to decompose polyvinyl alcohol; A microorganism belonging to the genus Cellulophaga, having a 16S rRNA gene consisting of a base sequence showing 80% or more sequence identity with the base sequence of SEQ ID NO: 2, and having the ability to decompose polyvinyl alcohol; and A microorganism belonging to the genus Vibrio, having a 16S rRNA gene consisting of a base sequence showing 80% or more sequence identity with the base sequence of SEQ ID NO: 3, and having the ability to decompose polyvinyl alcohol; A method for producing a decomposition product of polyvinyl alcohols, comprising a step of contacting one or more microorganisms selected from the group consisting of: [Effects of the Invention]

[0009] The present invention provides a technology for decomposing polyvinyl alcohols using marine polyvinyl alcohol-decomposing microorganisms. [Brief explanation of the drawings]

[0010] [Figure 1] 1 shows the results of measuring the PVOH decomposition activity of PVOH-decomposing microorganisms. DETAILED DESCRIPTION OF THE INVENTION

[0011] A preferred embodiment for carrying out the present invention will be described below. Note that the embodiment described below is an example of a typical embodiment of the present invention, and the scope of the present invention should not be construed as being narrow.

[0012] [Polyvinyl alcohols] The polyvinyl alcohols (PVOHs) of the present invention are obtained by saponifying a polyvinyl ester resin obtained by polymerization of a vinyl ester monomer, and have vinyl alcohol units as the main constituent units and vinyl ester units such as vinyl acetate depending on the degree of saponification.

[0013] The PVOHs in the present invention may be unmodified PVOHs consisting only of vinyl alcohol units and vinyl ester units, or may be PVOH resins having various modifying groups. Examples of PVOH resins having modifying groups include modified PVOH resins obtained by copolymerizing various monomers during the production of a vinyl ester resin and then saponifying the copolymer, and modified PVOH resins obtained by post-modifying unmodified PVOH to introduce various functional groups.

[0014] Examples of vinyl ester monomers include vinyl formate, vinyl acetate, vinyl trifluoroacetate, vinyl propionate, vinyl butyrate, vinyl caprate, vinyl laurate, vinyl versatate, vinyl palmitate, and vinyl stearate. These may be used alone or in combination of two or more. Of the vinyl ester monomers, vinyl acetate is preferred.

[0015] Monomers used for copolymerization with vinyl ester monomers include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxyl-containing α-olefins such as 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, and 3,4-dihydroxy-1-butene, as well as their acylated derivatives; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, and itaconic acid, as well as their salts, monoesters, and dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; and diacetone acrylamide. olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, or their salts; vinyl compounds such as alkyl vinyl ethers, dimethyl allyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene carbonate, 2,2-dialkyl-4-vinyl-1,3-dioxolane, glycerin monoallyl ether, and 3,4-diacetoxy-1-butene; substituted vinyl acetates such as isopropenyl acetate and 1-methoxyvinyl acetate; vinylidene chloride, 1,4-diacetoxy-2-butene, and vinylene carbonate.

[0016] Examples of modified PVOH-based resins into which functional groups have been introduced by post-modification include those having acetoacetyl groups by reaction with diketene, those having polyalkylene oxide groups by reaction with ethylene oxide, those having hydroxyalkyl groups by reaction with epoxy compounds, etc., and those obtained by acetalizing PVOH with aldehyde compounds having various functional groups.

[0017] The polymerization (or copolymerization) method is not particularly limited, and any known polymerization method such as solution polymerization, emulsion polymerization, or suspension polymerization can be used. Solution polymerization using an alcohol such as methanol, ethanol, or isopropyl alcohol as a solvent is preferred.

[0018] The polymerization reaction is carried out using a known radical polymerization catalyst such as azobisisobutyronitrile, acetyl peroxide, benzoyl peroxide, or lauroyl peroxide.

[0019] Saponification of polyvinyl ester resins is carried out by dissolving the resin in alcohol or an alcohol / fatty acid ester mixed solvent in the presence of an alkali catalyst. Examples of alcohols include methanol, ethanol, and butanol. Examples of fatty acid ester solvents include methyl acetate, ethyl acetate, and butyl acetate. Other solvents such as benzene and hexane may also be used in combination.

[0020] As the saponification catalyst, an alkali catalyst such as an alkali metal hydroxide or alcoholate, such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate, potassium methylate, etc. Saponification can also be carried out using an acid catalyst, such as hydrochloric acid, sulfuric acid, or p-toluenesulfonic acid.

[0021] The form of the PVOH in the present invention is not particularly limited, and may be a powder, a film, a pellet, or the like.

[0022] [Polyvinyl alcohol-degrading microorganisms] The polyvinyl alcohol-decomposing microorganism (PVOH-decomposing microorganism) according to the present invention is preferably derived from the ocean and is any one of the following strains: (1) Leisingera caerulea PA2 strain. (2) Cellulophaga lytica PA0 strain. (3) Vibrio alginolyticus strain SSW-PVOH1. (4) Hyphomonas jannaschiana MK PVOH-1 strain. (5) Alteromonas macleodii strain WSW-PVOH1.

[0023] The above strains (1)-(3) have been internationally deposited at the National Institute of Technology and Evaluation (NPMD) Patent Microorganism Depositary (Room 122, 2-5-8 Kazusa Kamatari, Kisarazu City, Chiba Prefecture), which is a depository institution under Article 27-2 and 2-3 of the Regulations for Enforcement of the Patent Act and an international depositary authority under the Budapest Treaty on the International Recognition of the Deposit of Microorganisms. The accession numbers for the above strains (1)-(3) are NITE ABP-03432, NITE ABP-03433, and NITE ABP-03434, respectively, and the dates of receipt for all strains are March 12, 2021.

[0024] The PVOH-degrading microorganism may be a closely related strain belonging to the same species as the above strains (1) to (5). Examples of closely related strains include any of the following microorganisms: (1-1) Strains belonging to Leisingera caerulea. (2-1) Strains belonging to Cellulophaga lytica. (3-1) Strains belonging to Vibrio alginolyticus. (4-1) A strain belonging to Hyphomonas jannaschiana. (5-1) Strains belonging to Alteromonas macleodii These closely related strains are expected to have polyvinyl alcohol decomposition activity similar to that of the strains (1)-(5) above.

[0025] Furthermore, the PVOH-degrading microorganism may be a closely related species belonging to the same genus as the above strains (1) to (5). Examples of closely related species include any of the following microorganisms: (1-2) A microorganism belonging to the genus Leisingera, preferably Leisingera caerulea, having a 16S rRNA gene consisting of a nucleotide sequence showing 80% or more sequence identity with the nucleotide sequence of SEQ ID NO: 1. (2-2) A microorganism belonging to the genus Cellulophaga, preferably Cellulophaga lytica, having a 16S rRNA gene consisting of a nucleotide sequence showing 80% or more sequence identity with the nucleotide sequence of SEQ ID NO: 2. (3-2) A microorganism belonging to the genus Vibrio, preferably Vibrio alginolyticus, having a 16S rRNA gene consisting of a nucleotide sequence showing 80% or more sequence identity with the nucleotide sequence of SEQ ID NO: 3. (4-2) A microorganism belonging to the genus Hyphomonas, preferably Hyphomonas jannaschiana, having a 16S rRNA gene consisting of a nucleotide sequence showing 80% or more sequence identity with the nucleotide sequence of SEQ ID NO: 4. (5-2) A microorganism belonging to the genus Alteromonas, preferably Alteromonas macleodii, having a 16S rRNA gene consisting of a nucleotide sequence showing 80% or more sequence identity with the 16S rRNA gene sequence of the Alteromonas macleodii WSW-PVOH1 strain. These closely related species are expected to have polyvinyl alcohol decomposition activity similar to that of the strains (1)-(5) above. In terms of retaining polyvinyl alcohol decomposition activity, the microorganisms (1-2) to (5-2) above have a 16S rRNA gene consisting of a nucleotide sequence that shows 85% or more, 90% or more, preferably 95% or more, 98% or more, more preferably 99% or more, or 99.5% or more sequence identity to the nucleotide sequences of SEQ ID NOs: 1 to 4, respectively, and to the nucleotide sequence of the 16S rRNA gene possessed by the Alteromonas macleodii WSW-PVOH1 strain. PVOH-degrading microorganisms suitable for the present invention can be obtained by selecting candidate microorganisms from microorganisms belonging to the above-mentioned taxonomic genera or species based on sequence identity of the nucleotide sequence of the 16S rRNA gene and evaluating the PVOH-degrading ability of the candidate microorganisms.

[0026] For methods of analyzing and identifying rRNA genes, reference can be made to, for example, "Gene Analysis Method: 16S rRNA Gene Sequencing Method (Classification and Identification of Actinomycetes, edited by the Japanese Society of Actinomycetes, pp. 88-117, 2001)," "Bulletin of the Japanese Society of Microbial Ecology, Vol. 10, 31-42, 1995," and "16th Revised Japanese Pharmacopoeia: Rapid Identification of Microorganisms by Genetic Analysis."

[0027] The ability to decompose PVOH can be evaluated, for example, by measuring biological oxygen demand (BOD), confirming growth in a medium containing only PVOH as a carbon source, confirming molecular weight distribution by gel permeation chromatography (GPC), or observing coloration with iodine.

[0028] [Heatened bacterial cells / culture supernatant] The above-mentioned PVOH-decomposing microorganism may be used in the form of a culture solution as is, or may be used in the form of cells or a processed product thereof, or a culture supernatant obtained by collecting cells from the culture solution by centrifugation or the like. Examples of treated bacterial cells include bacterial cells treated with acetone, toluene, etc., freeze-dried bacterial cells, disrupted bacterial cells, cell-free extracts, and crude or purified enzymes extracted from these. Of the treated bacterial cells, enzymes (PVOH-degrading enzymes) are particularly preferred.

[0029] [Recombinant microorganisms] The PVOH-degrading enzyme may be isolated and purified from the above-mentioned microorganisms, or may be expressed in a recombinant microorganism using conventionally known molecular biology techniques and then purified. Recombinant microorganisms are produced by introducing a nucleic acid encoding the PVOH-degrading enzyme into a common host vector system and transforming a microorganism with the vector system. Examples of hosts include bacteria such as Escherichia coli, Rhodococcus, Pseudomonas, Corynebacterium, Bacillus, Streptococcus, and Streptomyces, yeasts such as Saccharomyces, Candida, Shizosaccharomyces, and Pichia, and filamentous fungi such as Aspergillus. Among these, Escherichia coli is particularly preferred for its simplicity and efficiency.

[0030] [Method for decomposing polyvinyl alcohols] Polyvinyl alcohols can be decomposed by contacting a PVOH-decomposing microorganism, a recombinant microorganism thereof, or a treated cell product thereof with polyvinyl alcohols. The decomposition of polyvinyl alcohols can be confirmed, for example, by measuring biological oxygen demand (BOD), confirming growth in a medium containing PVOH as a single carbon source, confirming molecular weight distribution by gel permeation chromatography (GPC), or observing coloration with iodine.

[0031] The step of contacting the PVOH-degrading microorganism, its recombinant microorganism, or a treated product of the microorganism or its cells with polyvinyl alcohols may be carried out in an appropriate solvent, which is usually an aqueous solvent such as a buffer solution. The PVOH-degrading microorganism of the present invention is derived from the ocean and exhibits hydrolytic activity even under high salt concentrations, allowing the enzymatic reaction to occur even in a solvent with a high salt concentration (e.g., an NaCl concentration of 3% by weight or more). Therefore, seawater, which is inexpensive, easy to use, and available in large quantities, can be used as a solvent, contributing to the effective use of water resources.

[0032] The time, temperature, pH, and amount of enzyme added for the enzymatic reaction are not particularly limited and can be adjusted appropriately. The reaction temperature and time are usually 10-60°C for 1 hour to 1 week, preferably 20-50°C for 1 day or more, and more preferably 30-40°C for 3 days or more. The pH conditions for the enzyme reaction are also in the range of, for example, pH 4 to 10, preferably pH 5.0 to 9.0. The amount of the enzyme to be added is, for example, 0.001-20% (w / w), preferably 0.01-10% (w / w), more preferably 0.1-5% (w / w), based on the amount of polyvinyl alcohols.

[0033] The decomposition products of polyvinyl alcohols produced may be recovered and used for resynthesis of polyvinyl alcohols. The decomposition products of polyvinyl alcohols are determined depending on the type of polyvinyl alcohol, but may be, for example, vinyl alcohol oligomers having terminal carboxyl groups or ketone groups, and acetate esters thereof.

[0034] [Resin composition] The resin composition according to the present invention, which contains a culture supernatant or treated bacterial cell product of a PVOH-degrading microorganism and polyvinyl alcohols, exhibits excellent biodegradability. The resin composition according to the present invention is typically biodegraded in at least one of seawater, freshwater, brackish water, soil, and compost. Furthermore, since the amount of microorganisms in seawater is particularly low, a resin composition with high biodegradability in seawater (marine biodegradable resin composition) is preferred. Even when the resin composition according to the present invention is dumped in the ocean, for example, it is expected to be decomposed in seawater because the enzyme exhibits hydrolytic activity even at high salt concentrations.

[0035] In the resin composition according to the present invention, one type of polyvinyl alcohol may be used alone, or two or more types of polyvinyl alcohol may be used in any combination and ratio.

[0036] The amount of culture supernatant or treated bacterial cells of PVOH-decomposing microorganisms to be blended relative to polyvinyl alcohols in the resin composition is not particularly limited, but is, for example, 0.001-20% (w / w), preferably 0.01-10% (w / w), and more preferably 0.1-5% (w / w).

[0037] The culture supernatant or treated cells of the PVOH-degrading microorganism can be blended into the resin composition as is, or in a state where it is filled in water-soluble capsules, or immobilized on a carrier such as microspheres. [Example]

[0038] Example 1: Isolation of PVOH-degrading microorganisms from the ocean PVOH medium 1 was prepared by dissolving 1 g / L NH4Cl, 1 g / L K2HPO4, 1 g / L yeast extract, and 3 g / L PVOH in 1 L of artificial seawater. 1 mL of seawater was concentrated to a volume ratio of 1 / 100 using an ultrafiltration membrane (Q2000 150E, molecular weight cutoff 200,000 Da), and inoculated into 30 mL of PVOH medium 1 to initiate primary culture. The culture was incubated at 30°C with shaking for 1 week. PVOH medium 2 was prepared by dissolving 1 g / L NH4Cl, 0.05 g / L K2HPO4, 0.1 g / L Yeast Extract, and 10 g / L PVOH in 1 L of artificial seawater. 1 mL of the primary culture was inoculated into 30 mL of PVOH medium 2 to initiate secondary culture. The culture was performed with shaking at 30°C for 3 weeks. 40 μL of each primary and secondary culture medium was streaked onto a PVOH single-carbon-source agar medium and cultured at 30°C. The agar medium was prepared by dissolving 0.1% NH4Cl, 0.05 g / L K2HPO4, 10 g / L PVOH, and 15 g / L agarose in artificial seawater. The resulting colonies were streaked onto new agar medium and further cultured at 30°C to isolate Bacteria 1 and 2.

[0039] A medium was prepared by dissolving 4.6 g / L KH2PO4, 11.8 g / L Na2HPO4·12H2O, 0.5 g / L MgSO4·7H2O, 1.0 g / L NH4Cl, 0.1 g / L FeCl3·6H2O, and 30 g / L NaCl in 1 L of water. An equal volume of seawater was added to the medium, and PVOH was then added to a final concentration of 2 g / L. The medium was then cultured at 30°C for one week with shaking. 1 mL of the culture was then inoculated into the same medium and cultured again. This process was repeated once more. The culture solution diluted 10 to 100 times was applied to an agar medium and cultured at 30°C to isolate Bacterium 3. The agar medium was prepared by dissolving 15 g / L of agarose in the same medium.

[0040] Genomic DNA was extracted from the isolated bacteria 1-3, and the nucleotide sequences of the 16S rRNA region were determined. From the sequence information obtained, bacteria 1 was identified as Leisingera caerulea strain PA2, bacteria 2 as Cellulophaga lytica strain PA0, and bacteria 3 as Vibrio alginolyticus strain SSW-PVOH1.

[0041] [Example 2: Evaluation of PVOH resolution] The PVOH decomposition activity of bacteria 1-3 was measured using biological oxygen demand (BOD) as an index. BOD was measured using a BOD measuring device Oxitop manufactured by Central Scientific Co., Ltd. The BOD test system was prepared as follows. Seawater was filtered through an 11 μm filter, and 0.1 g / L KH2PO4, 0.5 g / L NH4Cl, and 0.3 g / L PVOH were added. The mixture was stirred and dispensed into Oxitop bottles in 100 mL portions.

[0042] The decomposing bacteria were cultured according to the following procedure. 1 g / L NH4Cl, 0.05 g / L K2HPO4, and 1 g / L PVOH were dissolved in 1 L of artificial seawater and mixed with an equal volume of Difco Marine Broth 2216 medium to prepare a medium. Strains 1-3 were each inoculated into one loop of medium and cultured at 30°C for 3 days. The culture was centrifuged to collect the bacterial cells. The collected bacterial cells were suspended in artificial seawater and centrifuged again to collect the bacterial cells.

[0043] The bacterial cells were suspended in 1 mL of artificial seawater and inoculated into the BOD test system. A control group without bacterial inoculation was also prepared as a control. A NaOH reservoir and an Oxitop sensor were attached to the reaction vessel, and BOD measurements were performed at 30°C.

[0044] The results of measuring the biodegradability of PVOH using BOD as an indicator are shown in Figure 1. The biodegradability of PVOH was confirmed for bacteria 1-3. [Sequence List Free Text]

[0045] SEQ ID NO: 1: Base sequence of 16sRNA of Bacterium 1 (Leisingera caerulea PA2 strain) SEQ ID NO: 2: Base sequence of 16sRNA of Bacterium 2 (Cellulophaga lytica PA0 strain) SEQ ID NO: 3: Base sequence of 16sRNA of Bacterium 3 (Vibrio alginolyticus SSW-PVOH1 strain) SEQ ID NO: 4: 16S rRNA sequence of Bacterium 4 (Hyphomonas jannaschiana MK PVOH-1 strain)

Claims

1. A microorganism belonging to the genus Leisingera caerulea, having a 16S rRNA gene consisting of a base sequence showing 95% or more sequence identity with the base sequence of SEQ ID NO: 1, and having the ability to decompose polyvinyl alcohol; and A microorganism belonging to the genus Cellulophaga lytica, having a 16S rRNA gene consisting of a base sequence showing 95% or more sequence identity with the base sequence of SEQ ID NO: 2, and having the ability to decompose polyvinyl alcohol; A method for decomposing polyvinyl alcohols, comprising a step of contacting polyvinyl alcohols with one or more microorganisms selected from the group consisting of:

2. A method for decomposing polyvinyl alcohols, comprising the step of contacting polyvinyl alcohols with a microorganism and / or a processed product of the microorganism, which belongs to the genus Vibrio alginolyticus, has a 16S rRNA gene consisting of a base sequence showing 95% or more sequence identity with the base sequence of SEQ ID NO: 3, and has the ability to decompose polyvinyl alcohol, in seawater.

3. the microorganism belonging to Leisingera caerulea is Leisingera caerulea PA2 strain (accession number: NITE BP-03432); the microorganism belonging to Cellulophaga lytica is Cellulophaga lytica PA0 strain (accession number: NITE BP-03433); The decomposition method according to claim 1 or 2, wherein the microorganism belonging to Vibrio alginolyticus is Vibrio alginolyticus SSW-PVOH1 strain (accession number: NITE BP-03434).

4. The decomposition method according to any one of claims 1 to 3, wherein the step is carried out in a solvent having a sodium chloride concentration of 3% by weight or more.

5. Leisingera caerulea PA2 strain (accession number: NITE BP-03432).

6. Cellulophaga lytica PA0 strain (accession number: NITE BP-03433).

7. Vibrio alginolyticus SSW-PVOH1 strain (accession number: NITE BP-03434).

8. A culture supernatant of the microorganism according to any one of claims 5 to 7.

9. A treated product of microbial cells according to any one of claims 5 to 7.

10. A resin composition comprising the culture supernatant according to claim 8 or the treated bacterial cell product according to claim 9, and polyvinyl alcohols.

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