JP3045563B2 - Chitin nonwoven fabric and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film-like nonwoven fabric comprising chitin or its derivative, chitosan, which is useful as an immobilizing carrier for enzymes, microorganisms, cells, etc., a wound covering material, artificial skin, or a metal adsorbent. It relates to the manufacturing method.

[0002]

2. Description of the Related Art Chitin is a kind of aminopolysaccharide which exists widely in nature such as the exoskeleton of crustaceans such as shrimp and crab, or the cell wall of fungi such as filamentous fungi. Chitosan is a deacetylated product of chitin. . These are known to have affinity for living bodies, adsorption of proteins such as enzymes, ability to form chelates with metal ions, and effect of promoting healing of wounds. It is being studied to make it into a sheet for the purpose of utilizing it.

[0003] For example, British Patent Publication GB21658
In 65A, a filamentous fungus containing chitin is cultured in a liquid medium to grow the hyphae, alkali-treated to expose a chitin layer from the mycelium, and then mixed with other fibers such as pulp and mechanically stirred. A method of obtaining a nonwoven fabric by dispersing and then making paper is disclosed. The nonwoven fabric shown here is paper-like and lacks flexibility because it is obtained by wet papermaking, and uses a mycelium that has been cut and shortened by stirring, so it has a low porosity and low air permeability and liquid permeability. For bad reasons, it was not suitable for use as an immobilized carrier for enzymes, microorganisms, cells, etc., wound dressing, artificial skin, or metal adsorbent.

[0004] In liquid culture, it is difficult to obtain a mycelium in which hyphae are uniformly dispersed. Therefore, in order to obtain a uniform nonwoven fabric, it was necessary to disperse the mycelium by mechanical stirring.
Due to this mechanical stirring, the entanglement of the hyphae is cut off, so that the dispersed mycelium is wet-formed again, and fibers such as pulp must be mixed in order to obtain sufficient strength for practical use. Was. Therefore, the resulting nonwoven fabric is
In addition to filamentous fungal hyphae, it contains fibers such as pulp, that is, those that do not contain chitin, so the content of chitin is low, and it cannot be said that the superior properties of chitin are effectively utilized. Was. Therefore, a nonwoven fabric consisting only of a mycelium containing chitin has been desired.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a chitin nonwoven fabric which is composed of only a mycelium containing chitin and has flexibility, high air permeability and liquid permeability, and a method for producing the same. .

[0006]

SUMMARY OF THE INVENTION The present invention consists only mycelia filamentous fungi containing chitin, chitin nonwoven fabric, characterized in that chitin on the surface of hyphae constituting the fungus yarn body is exposed A method for producing a chitin nonwoven fabric, comprising: culturing a filamentous fungus containing chitin on a solid medium, forming a mycelium, dissolving and removing the solid medium by heat treatment, and applying an alkali treatment. .

[0007]

In the present invention, chitin includes poly-N-acetyl-D-glucosamine or chitosan which is a deacetylated product thereof, and a filamentous fungus containing these substances in the cell wall is used as a chitin source. By subjecting the hyphae of these filamentous fungi to alkali treatment and dissolving and removing soluble S-glucan, proteins and lipids present in the cell wall together with chitin, the chitin layer can be exposed on the surface of the hyphae. The mycelium after the alkali treatment contains R-glucan which is insoluble in alkali, in addition to the chitin layer, but does not cause any problem.

[0008] The hyphae of filamentous fungi have the property of extending in all directions while branching or fusing, and intertwining to form mycelia. However, in liquid culture, aggregation of mycelia or formation of pellets occurs, so that it was substantially impossible to take out mycelium itself and use it as a nonwoven fabric. On the other hand, mycelium obtained by solid culture has a mycelium that branches and extends uniformly,
Since the mycelium forms a layer and grows at the interface of the solid medium and becomes a dense membrane-like mycelium, particularly at the interface of the solid medium, the mycelium itself is taken out and used as a nonwoven fabric. It has been found that the present invention is possible, and the present invention has been completed.

In the present invention, the chitin nonwoven fabric refers to one obtained by subjecting a mycelium taken out of a solid medium to the above-mentioned alkali treatment to expose a chitin layer from the cell wall of the mycelium.

The binding of hyphae in the chitin nonwoven fabric of the present invention is all due to the fusion or entanglement of hyphae by branching and elongation of the hyphae, and not by papermaking. And also has a sufficient porosity. In addition, fibers and the like containing no chitin are not mixed at all, so that a fiber having a high chitin content can be obtained.

Further, at the interface of the solid medium, the mycelium forms a layer and grows. Therefore, the obtained chitin nonwoven fabric has a film-like surface having a pore diameter of several μm on the side in contact with the solid medium. The hole diameter of the opposite surface is about several tens of μm.

According to the production method of the present invention, the mycelium does not form a pellet during the culturing, so that the filamentous fungi include Aspergillus genus and Penicillium (Penici).
llium), Mucor, Neurospora (Neuros)
pora), Phycomyces, Choanephora, Zygorhynchus
Any substance can be used as long as it contains chitin in the cell wall of a hypha such as a genus or a genus Rhizopus.
Among them, it is preferable to use a kind having a high chitin content, such as Neurospora crassa, because the excellent properties of chitin can be effectively used. In addition, when used in applications requiring flexibility, it is preferable to use a type having a thin mycelium such as mold, since a chitin nonwoven fabric having excellent flexibility can be obtained. In addition, when used as a wound dressing material, chitosan having a high degree of deacetylation has a disadvantage that it is easily dissolved by body fluids.
Blue mold, Lactobacillus and the like are more preferred.

When high strength is required, a net,
It can also be reinforced with a fibrous material having flexibility and air permeability, such as a knit, woven or nonwoven fabric. For example, when used as a wound dressing material, if the above fibrous material is laminated and reinforced on a surface that does not come into contact with the skin, the properties of chitin are not impaired.

Hereinafter, the method for producing the chitin nonwoven fabric of the present invention will be described in detail.

As the solid medium, an agar medium for growing filamentous fungi or the like can be used. After autoclaving these media, sterile petri dishes before solidifying,
Alternatively, the mixture is poured into a large container having a flat bottom such as an Erlenmeyer flask, solidified by cooling, and used as a plate agar medium. For example, when an Erlenmeyer flask is used, about 1/5 of the volume of the agar medium is poured, so that when the mycelium is separated from the agar medium described below, the agar medium is reduced to about 5 times with water. Since the concentration of the agar medium can be reduced by dilution, separation and washing of mycelium can be easily performed.

The agar medium is inoculated with spores of filamentous fungi and cultured in saturated steam at 30 ° C., and the culture is terminated before mycelia are formed and new spores are formed. The inoculation amount of spores is, for example, 1
The standard platinum loop volume is appropriate, and the culture time is about 2 to 3 days. The above operations are all performed aseptically.

After the cultivation is completed, an appropriate amount of water is added to the culture vessel and autoclaved to kill the fungi and simultaneously dissolve the agar. After the treatment, the petri dish is removed from the sterilizer before the agar medium is cooled and solidified. The mycelium is separated from the culture medium using tweezers or the like. When an Erlenmeyer flask is used as described above, before the autoclave treatment, about 5 times the volume of the agar medium can be added, so that the concentration of the medium after the autoclave treatment can be reduced. Therefore, the separation of the mycelium is facilitated, and the adherence of the medium to the separated mycelium can be reduced, so that the washing is also easy.

The mycelium separated from the culture medium is washed with water, and the water-soluble glucan in the outer layer of the cell wall of the mycelium and the medium component to which the mycelium adheres are washed away, and treated with a strong alkali such as a 1N aqueous sodium hydroxide solution. Then, the alkali-soluble S-glucan present in the intermediate layer of the cell wall and the protein present together with chitin in the inner layer are removed to expose the chitin layer. The alkali treatment is sufficient if it is immersed for about 2 hours in a 1N aqueous sodium hydroxide solution in which the mycelium is immersed.

After the alkali treatment, the product is washed with water until it becomes neutral and dried to obtain the intended chitin nonwoven fabric. As for the drying method, if heat is applied in a dry state, the mycelium shrinks. Therefore, vacuum drying or natural drying is preferable.

When reinforcement is required, the desired chitin nonwoven fabric is obtained and then laminated with the above-mentioned fibrous material with an adhesive or the like, or sterilized before separating the mycelium from the agar medium. Can be obtained by aseptically placing the fibrous material on the mycelium and intertwining the mycelium with the constituent fibers of the fibrous material by the growth of the mycelium. In the case of the latter method, it is necessary to use alkali-resistant and autoclave-resistant fibers as constituent fibers of the fibrous material.

[0021]

【Example】

Adjustment glucose agar for Example 1 filamentous fungus _{culture: 20g, MgSO 4 · 7H 2} O: 0.12g,
KH ₂ PO ₄ : 0.15 g, (NH ₄ ) ₂ HPO ₄ : 0.5 g,
Peptone: 0.2 g, malt extract: 4.5 g, agar: 20 g
Was dissolved in distilled water to make 1000 ml, and the pH was adjusted to 7.0.

The agar medium was sterilized in an autoclave sterilizer at 121 ° C. for 15 minutes, cooled to about 50 ° C., taken out, and sterilized by dry heat in advance.
100 ml was poured into a ml Erlenmeyer flask, cooled and solidified to obtain a plate agar medium. A spore of Rhizopus niveus IAM6035 strain is inoculated as a filamentous fungus into the plate agar medium in a standard loop amount, and the spores are inoculated in saturated steam at 30 ° C. for 3 hours.
Cultured for days. The above operation was performed aseptically.

After adding 300 ml of water to the Erlenmeyer flask, the mixture was autoclaved under the same conditions as above,
After cooling, the mycelium was separated from the medium.

The separated mycelium is immersed in a liquid tank containing 500 ml of water for 1 hour, and then immersed in a liquid tank containing 200 ml of 1N sodium hydroxide aqueous solution for 2 hours. Thus, a chitin nonwoven fabric with the chitin exposed on the surface of the hypha was obtained.

The obtained chitin nonwoven fabric has a basis weight of 15 g / m ² ,
The thickness was 0.03 mm, and the hole diameter was 7 to 24 μm.

Example 2 As a filamentous fungus, Neurospora crasa
ssa IFO6178 strain) was used in the same manner as in Example 1 to obtain a chitin nonwoven fabric. The obtained chitin nonwoven fabric is
The basis weight was 15 g / m ² , the thickness was 0.03 mm, and the pore size was 3 to 21 μm.

[0027] Aspergillus niger as Example 3 filamentous fungi (Aspergillus ni
ger IAM2094 strain), except that chitin nonwoven fabric was obtained in the same manner as in Example 1. The obtained chitin nonwoven fabric is
The basis weight was 19 g / m ² , the thickness was 0.03 mm, and the pore size was 3 to 20 μm.

Each of the chitin nonwoven fabrics was flexible and had good air permeability, and was suitable as a wound dressing.

[0029]

According to the production method of the present invention, a chitin nonwoven fabric can be formed only by fusion or entanglement of hyphae by branching and elongation of hyphae without using a web forming means such as wet papermaking. Therefore, the obtained chitin nonwoven fabric has a film shape and flexibility, and has sufficient air permeability and liquid permeability, and thus exhibits characteristics suitable for a wound dressing or the like. Moreover, since the chitin nonwoven fabric of the present invention is composed of only the hypha with the chitin exposed, a chitin nonwoven fabric having a high chitin content can be obtained.

Claims (2)

(57) [Claims] 1. A chitin nonwoven fabric comprising only mycelia of a filamentous fungus containing chitin, wherein chitin is exposed on the surface of hyphae constituting the mycelium. 2. A method for producing a chitin nonwoven fabric, comprising: culturing a chitin-containing filamentous fungus on a solid medium, forming a mycelium, heat-treating the solid medium, removing the solid medium, and performing an alkali treatment. Method.