JPH0771502B2 - Decomposition method of polyamide polymer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decomposing a polyamide polymer compound, and more particularly to a new industrial method capable of decomposing water-insoluble polymer nylon etc. strongly. Is.

Therefore, the present invention not only makes a great contribution to the treatment of plastic waste, whose treatment is now a major social problem, but also elucidates the decomposition mechanism to design biodegradable polymer compounds. It is also a great expectation.

[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).

[0005]

What is particularly problematic in the treatment of plastic waste is not the treatment of water-soluble plastics but the treatment of water-insoluble polymer substances that are insoluble in water. The same applies to things. However, as is clear from the above, the conventional method cannot decompose the water-insoluble nylon, and this cannot achieve the intended purpose.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the present state of the art in order to prevent plastic pollution, and is a water-insoluble polyamide that cannot be decomposed by conventional methods. The high-molecular compounds are also made for the purpose of developing a method capable of efficiently decomposing.

[0007] In order to achieve the above object, studies were conducted, and from the viewpoint of preventing secondary pollution, attention was paid to biological treatment, continuing from the conventional method. However, although attention was paid to bacteria according to the conventional method and various bacteria were examined, the desired bacteria could not be found.

Therefore, it was decided to widely study other microorganisms, and attention was first focused on wood-destroying fungi that have no relation to the decomposition of plastics such as nylon. However,
Since the intended purpose was not achieved, the necessity of a major change in the idea of culture conditions, treatment conditions, etc. was recognized.

Therefore, nitrogen sources and / or carbon sources, which are nutrient components necessary for the growth and treatment of microorganisms and which should not be reduced by addition, are cut out in a manner contrary to common general technical knowledge. As a result of treating the polyamide-based polymer compound into a powder form, it succeeded in decomposing an insoluble polymer that could not be conventionally decomposed, and completed the present invention. The present invention will be described in detail below, but in the present specification, the polyamide-based polymer compound may be referred to as nylon.

In order to carry out the present invention, it is necessary to cultivate the polyamide polymer compound to be decomposed by a wood-destroying basidiomycete on a medium having a reduced nitrogen content and / or carbon content. is there.

In the present invention, Lentinus l
Wood-destroying basidiomycetes including brown-rotting basidiomycetes such as epideus can be widely used, and particularly white-rotting basidiomycetes, that is, lignin-degrading bacteria can be advantageously used.

As these wood-destroying basidiomycetes, microorganisms belonging to the following genera are widely exemplified: Coriolus versicolor IFO.
7043 etc.), genus Phanelocete (Phaneroc)
haete chrysosporium ATCC
34541), Trametesdi (Trametesdi)
ckinsii IFO 6488 etc., Polyporus genus (Polyporus mikadoi IFO 65
17, etc., genus Stereumfrustu
losum IFO 4932 etc.), Ganoderma (G
anoderoma applanatum IFO 6
499), Lentites bet
ulina IFO 8714 etc.), genus (Fo)
mes fomentarius IFO 30371
Etc.), Porodisculus (Porodisculus)
s pendulus IFO 4967, etc., Lentinus edodes IFO 3
1336, L.S. lepideus IFO 7043
Etc.), genus of Serpula (Serpula lacryman)
s IFO 8697 etc.) Others.

As the wood-destroying basidiomycetes usable in the present invention, in addition to the above-mentioned microorganisms, NK-1148 strain (FERM BP-1859) can be used.
This strain can highly decompose polyamide polymer compounds. Details of the mycological properties of the NK-1148 strain are disclosed in JP-A-2-259180.

In the present invention, the polyamide polymer compound is treated with one or more of the above wood-destroying basidiomycetes and decomposed. In this case, the nitrogen concentration and / or carbon concentration in the medium are It is characterized by processing under restrictions.

Specifically, the polyamide polymer compound is placed on and / or mixed with a medium in which the nitrogen concentration and / or carbon concentration is limited, and this is inoculated with a wood-destroying basidiomycete at an optimum temperature. For example, if static culture is performed at 15 to 35 ° C, 5
The polymer compound can be decomposed in about 30 days. The polyamide-based polymer compound can also be decomposed by liquid culture under the above-mentioned culture conditions (aeration and / or stirring).

In this case, it is important to limit the nitrogen concentration and / or the carbon concentration despite culturing the microorganism. The nitrogen concentration and / or the carbon concentration is preferably as small as possible, preferably not contained, but from an industrial viewpoint, it may be 0.1 g / l or less, and if it is 0.05 g / l or less. Even better results were obtained, and the carbon concentration was 0.2 g /
It may be set to 1 or less. There is no particular limitation on the medium composition other than nitrogen and carbon, and each component commonly used for growing wood-destroying fungi is appropriately used. In the present invention, if the above-mentioned conditions for nitrogen and / or carbon are satisfied, the intended purpose can be achieved regardless of whether it is solid culture or liquid culture. ,
For example, the polymer compound can also be decomposed by adding a polyamide polymer compound and a wood-destroying fungus to water alone (adding agar and / or a pH adjuster or the like if necessary) and incubating.

In the present invention, wood-destroying basidiomycetes are used, but in addition to the fungi themselves, cultures and / or processed products thereof can also be used. The culture broadly refers to a mixture of cells and a culture solution obtained by culturing a bacterium, but in the present invention, cells such as wet cake separated from the cell culture, its residue, and solids. It is also possible to use the culture medium after removing all the substances. Also,
The processed product is a product obtained by concentrating, drying, or diluting the above-mentioned products.

When the polyamide polymer compound is decomposed according to the present invention, these polymers may be used as they are, but they are pulverized to increase the contact area with the microorganism and the enzyme produced therefrom. It is preferable that it is made into a powder, a powder, or a porous film.

According to the present invention, in addition to nylon mm, nylon mn, and nylon n, which are linear synthetic polyamides among polyamides, a water-insoluble polymer (for example, a molecular weight of about 80 000-1
60,000) can also be decomposed. Therefore, according to the present invention, nylon 6, nylon 66, nylon 610, nylon 7, nylon 9, nylon 11,
Nylon 12 etc. can also be decomposed freely. Of course, these mixtures are also biodegradable. Examples of the present invention will be described below.

[0020]

Example 1 A nylon membrane having pores (nylon 66 membrane filter manufactured by Sartorius) was used as a solid medium (KH ₂ PO ₄ 1.0 g, NaH ₂ PO) containing no nitrogen source.
_{4 0.2g, MgSO 4 · 7H 2} O 0.1g, ZnS
_{O 4 · 7H 2 O 0.01mg,} CuSO 4 · 5H 2 O
0.02 mg, dimethyl succinate 1.46 g, gl
ucose 20g, Agar 30g, water 1l) and put on various microorganisms (white-rotting basidiomycetes; Phanero
chaete chysosporium ATCC 3
4541, Coriolus versicolor
IFO 7043, NK-1148 FERM BP-1
859, brown-rot basidiomycete; Lentinus lep
ideaus IFO 7043, Serpula la
crymans EPRI 6352, imperfect bacteria; As
pergillus niger IFO 6341,
Penicillium citrinum IFO6
352, bacteria; Bacillus subtillis
IFO 3134, Pseudomonas pau
20 to 2 inoculated with C. mobilis SYK-6)
Static culture was carried out at 8 ° C for 20 days. After culturing, the porous membrane was HFI
P (hexafluoroisopropanol) with a sample concentration of 0.
Dissolved to 2% and analyzed by GPC (Showa Denko column HFIP-80M; eluent HFIP; flow rate 1 ml /
min; temperature 40 ° C .; detector RI) Degradability was evaluated by the change in average molecular weight. The average molecular weight of the sample treated with the bacteria is shown in Table 1 below.

[0021]

[Table 1]

[0022]

[Example 2] Three types of white-rotting basidiomycetes (Phanerochaete ch.) Which were found to be decomposed in Example 1
ysosporium, Coriolus versi
colorer, NK-1148) according to the culturing conditions of Example 1, and a solid medium having a different nitrogen concentration (nitrogen concentration was 0 g / l, 0.05 g / l using ammonium tartrate,
0.10 g / l, 0.15 g / l, the other medium having the same medium composition as in Example 1) was subjected to static culture and the degradability was GP.
Checked in C. The results are shown in Table 2 below.

[0023]

[Table 2]

[0024]

[Example 3] Using the white-rot fungus (NK-1148), which was found to be decomposed in Example 1, solid medium having different carbon concentrations (carbon concentration 0 g /
Glucose was added so as to be 1, 0.2 g / l, 0.4 g / l, and 8.0 g / l, and dimethyl succinate and (NH ₄ ) ₂ SO ₄ were changed to 0 g and 0.58 g, respectively. Is the same medium composition as in Example 1) and the degradability was examined by GPC. The results are shown in Table 3 below.

[0025]

[Table 3]

[0026]

Example 4 Using the white-rot fungus (NK-1148), which was found to be decomposed in Example 1, a solid medium (glucose and (NH ₄ ) ₂ SO _{4 was} added in an amount of 0 g, and the other medium had the same medium composition as in Example 3), and static culture was carried out to examine the degradability by GPC. Moreover, a solid medium (Agar 30 g, water 1 l) obtained by removing all nutrients from the medium of Example 3.
However, static culture was performed and the degradability was examined by GPC in the same manner. The results are shown in Table 4.

[0027]

[Table 4]

[0028]

[Example 5] Phanerochaete under the nitrogen concentration conditions (ammonium tartrate 0 g / l, other conditions are the same as in Example 1) that showed the maximum decomposition ability in Example 2.
The effect of nylon morphology on degradability was investigated using chysosporium. As its form, a pore membrane (nylon 66 membrane filter manufactured by Sartorius),
Nylon film (Asahi Kasei Co., Ltd., thickness 50 μm), nylon 66 fiber (NBC Kogyo Co., Ltd. diameter 60 μm), and powder were used. The powder was classified by crushing the powder for 5 minutes with a sample mill (TI-100 manufactured by HEIKO) 4 to 5 times, and the 80 or more mesh fraction was used as a decomposition sample. The degradability was evaluated according to Example 1. The results are shown in Table 5 below.

[0029]

[Table 5]

[0030]

According to the present invention, a polyamide polymer compound such as a water-insoluble polymer nylon can be efficiently decomposed, and at the same time, it does not cause secondary pollution. The invention makes a great contribution to the treatment of plastic waste, the treatment of which is now a major social problem in the world.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C12R 1: 645) (C12P 13/02 C12R 1: 685) (C12P 13/02 C12R 1:80) (C12P 13/02 C12R 1: 125) (C12P 13/02 C12R 1:38) C08L 77:00

Claims (5)

[Claims] 1. A polyamide-based polymer compound having an added nitrogen concentration of 0.1 g / l and / or an added carbon concentration of 0.2 g.
A method for decomposing a polyamide polymer compound, which comprises treating with a wood-destroying basidiomycete under a culture condition having a composition of 1 / l or less. 2. The decomposition method according to claim 1, which is carried out under solid culture and / or liquid culture conditions. 3. The wood-rotting basidiomycete is a white-rotting basidiomycete, according to any one of claims 1 to 3.
Term decomposition method. 4. The wood-destroying basidiomycete is the microorganism itself,
The method for decomposing according to any one of claims 1 to 4, which is a culture of a microorganism and / or a treated product thereof. 5. The decomposition method according to any one of claims 1 to 5, wherein a polyamide-based polymer compound is used which is pulverized, powdered, and / or formed into a pore film.