JPH06121692A - Method for decomposing synthetic high molecular substance and decomposing agent - Google Patents

Abstract

PURPOSE:To decompose a synthetic high molecular substance as a method useful for treatment, etc., of industrial wastes such as plastic wastes by treating the synthetic high molecular substance containing a substance, capable of imparting the hydrophilicity and added thereto with a basidiomycete. CONSTITUTION:A synthetic high molecular substance (e.g. a nylon 66 pellet) is mixed with a substance capable of imparting the hydrophilicity (e.g. polyethylene glycol) and the resultant mixture is then dissolved in a solvent such as hexafluoroisopropanol to prepare a casting solution, which is further uniformly cast on a glass surface with a spreader for thin-layer chromatography to remove the hexafluoroisopropanol under reduced pressure. Thereby, a film of the synthetic high molecular substance having the hydrophilicity imparted thereto is obtained. The resultant film is placed on a solid culture medium and a basidiomycete or its culture or both are inoculated into the culture medium and subjected to the stationary culture at 28 deg.C for 10 days to biodegrade the film. The weight-average molecular weight of the synthetic high molecular substance is reduced from 187000 before the treatment with the fungus to 43000 thereafter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a degrading agent for degrading synthetic polymeric substances with basidiomycetes and / or cultures thereof.

The present invention contributes to the treatment of plastic waste, which is now a major social problem.

[0003]

2. Description of the Related Art Conventionally, as a method of decomposing a polyamide compound, bacteria (Flavobacterium sp.
I72) is known (Agr. Bio).
l. Chem. , 39 (6), 1219-1223 (1
975); Fermentation Engineering, 60 (5), 363-375 (1
982)).

However, all of these conventional methods are water-soluble low molecular weight nylon 6 oligomers (molecular weight of about 20).
00) and cannot decompose water-insoluble polymer nylon (molecular weight of about 10,000 or more).

Also known are biodegradable compositions in which starch granules are dispersed in a thermoplastic synthetic resin to make them susceptible to biological attack. (JP-A-49-55740)

However, this biodegradable composition
Only the contained starch granules undergo biodegradation, the synthetic resin is not decomposed, and the starch granules are not decomposed but disintegrated, and the synthetic resin still remains.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the current state of the art in order to prevent the pollution of plastics, and the constructions of various plastics which cannot be decomposed by conventional methods. It was made for the purpose of biodegrading the synthetic high molecular weight substance itself.

In the present invention, an enzyme produced by basidiomycetes cannot act on a non-hydrophilic synthetic polymer substance, but a substance imparting hydrophilicity is mixed or applied to the synthetic polymer substance to impart wettability. For example, it has been found that the synthetic polymer substance or plastic and the enzyme act to decompose the synthetic polymer substance itself.

As the synthetic polymer substance, polyethylene,
There are nylon, polypropylene, polyvinyl chloride, polystyrene, polyurethane, polyester, etc., which can be decomposed.

These synthetic polymer substances are plastics which can be decomposed by basidiomycetes by mixing with a substance which imparts hydrophilicity at the time of molding, or by applying a substance which imparts hydrophilicity after molding. It is what
The shape of the plastic may be a film shape or a shape.

The hydrophilicity-imparting substance is preferably added or applied in such an amount that the wettability of the surface of the plastic with water is 70 ° or less, preferably 60 ° or less.

Examples of the substance imparting hydrophilicity include starch, modified starch, cereal flour, mannitol, lactose, dextran, cellulose, CMC, casein, straight chain higher fatty acid,
There are organic substances such as linear higher alcohols, polyethylene glycol, polypropylene glycol, Tween 80, and various other surfactants.

Further, as the substance imparting hydrophilicity, there are inorganic substances such as diatomaceous earth, silica, alumina, calcium chloride, magnesium sulfate and sodium sulfate.

As a method for producing a plastic which can be decomposed by basidiomycetes, pellets of various synthetic polymer substances and one or more kinds of substances imparting hydrophilicity are appropriately mixed, depending on the intended molded product. It is better to mold according to the molding method. Alternatively, the surface of the molded synthetic polymer material may be simply coated with a substance that imparts hydrophilicity.

In the present invention, it is necessary for the enzyme produced by basidiomycete to have such wettability that it can act on the synthetic polymer or the plastic, and the addition amount of the substance imparting hydrophilicity is large for each substance. Although different, it is sufficient that the contact angle of the synthetic polymer or plastic surface with water is 70 ° or less, preferably 60 ° or less, which gives wettability. Enzymes produced by basidiomycetes act on synthetic polymeric substances or plastics that are given wettability,
It becomes possible to directly decompose various synthetic polymer substances.

The basidiomycetes may be naturally occurring ones, but since the abundance is low or the resolution is low, it is preferable to spray a decomposer containing basidiomycetes prepared separately by culture.

As the basidiomycetes used as the decomposing agent, microorganisms belonging to the following genera are widely exemplified: Coriolus versicolor IFO.
7043), Phanelocetes (Phaneroch)
aete chrysosporium ATCC 3
4541 etc., genus Trametes (Trametes di
cksinsii IFO 6488), etc.

In addition to the above-mentioned microorganisms, NK-11
Forty-eight strains (FERM BP-1859) can also be used, and this strain can highly decompose various synthetic resins. For details of the mycological properties of this NK-1148 strain, see JP-A-2-259180. No.

Decomposing agents containing basidiomycetes are generally produced by inoculating wood flour with various basidiomycetes and culturing them, and then further granulating them to produce them. The thing etc. can be used suitably.

If a basidiomycete preparation is sprayed on the waste of a synthetic polymer or a plastic which can be decomposed by basidiomycetes and / or a culture thereof by adding a substance imparting hydrophilicity, And / or the culture is capable of degrading synthetic polymeric substances and eliminating waste within a short period of time.

[0021]

Example 1 10 parts by weight of nylon 66 pellets (manufactured by Aldrich) and various additives for imparting hydrophilicity, polyethylene glycol (Wako Pure Chemical Industries), polypropylene glycol (Wako Pure Chemical Industries), Tween 80 (Kishida Chemical Co., Ltd.) Made) and silica (Mizukasil P made by Mizusawa Industry Co., Ltd.)
-700) 1 part by weight was mixed and then dissolved in 100 parts by weight of hexafluoroisopropanol to obtain a cast liquid.
This casting solution was uniformly cast on the glass surface using a thin layer chromatography splendor, and then hexefluoroisopropanol was removed under reduced pressure to obtain a hydrophilic nylon 66 film. Nylon 66 that does not contain various additives (no hydrophilic property)
The film was prepared in a similar manner. The contact angle of each of these films with water was measured by the sessile drop method (Polymer Society of Japan, Committee on Polymer and Water: Polymer and Moisture (Koushobo)).

These various films were applied to a solid medium (KH ₂ P
O ₄ 1.0 g, NaHPO ₄ 0.2 g, MgSO ₄ ·
_{7H 2 O 0.1g, ZnSO 4 ·} 7H 2 O 0.01m
g, CuSO ₄ .5H ₂ O 0.02 mg, glucos
e 20 g, Agar 30 g, water 1 l),
A microorganism (NK-1148) was inoculated and statically cultured at 28 ° C for 10 days. After culturing, the molecular weight of nylon 66 was measured to evaluate biodegradability.

The molecular weight was measured by high temperature GPC (150-C manufactured by Waters Co.). The measurement conditions are as follows: Column: Waters Microstyra Gel HT Linear and Ultra Styler Gel 500 Eluent: m-cr
Esol, flow rate: 1 ml / min, temperature: 100 ° C., detector: RI. Table 1 shows the average molecular weight of the sample after the bacterial treatment.
Shown in.

[0024]

[Table 1]

[0025]

[Example 2] Polyethylene (PE-1100 manufactured by Asahi Kasei Co., Ltd.) that is rendered hydrophilic by the addition of silica and polyethylene (PE manufactured by Asahi Kasei Co., Ltd.) that is not rendered hydrophilic.
-2100) was used, and the same biodegradation test as in Example 1 was performed except that the number of days of culture was 20 days. The molecular weight was measured by high temperature GPC (150-C manufactured by Waters Co.). The measurement conditions are as follows: Column: Waters Microstyra Gel HT Linear and Ultra Styler Gel 500, Eluent: Trichlorobenzene, Flow rate: 1
ml / min, temperature: 135 ° C., detector: RI.
Table 2 shows the average molecular weights of the samples after the bacterial treatment.

[0026]

[Table 2]

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Claims (6)

[Claims] 1. A method for biodegrading a synthetic polymer substance, which comprises treating the synthetic polymer substance to which a substance imparting hydrophilicity is added with a basidiomycete. 2. A synthetic polymeric substance degrading agent comprising basidiomycetes and / or a culture thereof. 3. A hydrophilicity-imparting substance is added in an amount that imparts a wettability of 70 ° or less, preferably 60 ° or less, with respect to water on the surface of a plastic molded from a synthetic polymer. The method for biodegrading the synthetic polymer substance according to claim 1. 4. The substance which imparts hydrophilicity is starch, modified starch, cereal flour, mannitol, lactose, dextran, cellulose, CMC, casein, higher fatty acid, higher alcohol, polyethylene glycol, polypropylene glycol, Tween 80, and various other substances. The method for biodegrading a synthetic polymer substance according to claim 1 or 3, which is an organic substance such as a surfactant. 5. The synthetic polymer substance according to claim 1, wherein the substance that imparts hydrophilicity is an inorganic substance such as diatomaceous earth, silica, alumina, calcium chloride, magnesium sulfate, and sodium sulfate. Biodegradation method. 6. The synthetic polymeric substance decomposing agent according to claim 2, wherein the basidiomycete is inoculated into a solid or liquid medium and cultured, and the resulting culture is used.