JP2012095570A - Method for producing immobilized trichoderma and method for storing timber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing immobilized trichoderma which surely selects an excellent strain from collected fungi of the genus Trichoderma, draws out performance of fungi of the genus Trichoderma, is fixed on an inexpensive and easily obtainable carrier material and has excellent practicality, and a method for storing timbers.SOLUTION: Immobilized trichoderma in which fungi of the genus Trichoderma of parasite fungi are immobilized on alkali charcoal in a living state are arranged in a ground part of a wooden civil engineering material to achieve decay delay of the part by wood rotting fungi.

Description

  The present invention relates to an immobilized Trichoderma produced by combining Trichoderma spp. Known as "Tussia mold" and general charcoal exhibiting alkalinity ("Immobilized Trichoderma" refers to Trichoderma spp. It is related with the wood preservation technique which delays decay of the earthing | grounding location of wooden engineering materials, without using antiseptic | preservative.

  As one of the measures for preventing and mitigating the progress of global warming, it has been proposed to replace part of the mineral resources and fossil resources currently consumed with biomass resources. One of the biomass resources is wood, which has been used as civil engineering and construction materials because of its high strength per unit gravity (specific strength). In addition, wood has the advantage that it consumes less energy for production and processing compared to metal and inorganic materials, and it is a material that itself has fixed carbon dioxide in the atmosphere, so it will be further in the future. Expansion of use is expected.

  On the other hand, wood may be attacked by organisms such as wood decay fungi (basidiomycetes of microorganisms) and termites (biodegradation), and as a result, the strength is reduced due to the weight loss due to the decomposition of the wood itself ( Decay). As a method for preventing this damage, techniques for applying and injecting various antiseptic / anticidal agents to wood have been established. However, due to chemical sensitivity and VOC (Volatile Organic Compounds), which have become social problems in recent years, it is often required to use wood without using chemicals. As a specific example, in the maintenance of parks used by infants and children, anti-septic / anticidal chemical treatment is applied to wooden playground equipment, wooden boardwalks, wooden fences, etc. (hereinafter referred to as wooden civil engineering materials) installed outdoors by park users. There are cases where things are disgusting and shunned.

  When attention is paid to the decay of wooden civil engineering materials caused by wood decaying fungi, it is known that damage is particularly likely to occur at ground contact points where the ground and wood contact. This is because the supply of moisture and nutrients from the ground and the oxygen supply from the atmosphere are continuously performed, and the activity of wood-rotting fungi that are aerobic microorganisms, such as basidiomycetes such as Ozu Ratake and Kawaratake, is activated. It is because it decomposes.

  If untreated timber is used outdoors as a wooden civil engineering material, it will depend on the wood type and thickness of the wood used, the moisture and temperature environment of the place where it is used, but the grounded part will become severely decayed in about 4 to 5 years at the earliest. It becomes necessary to replace the members.

  Untreated wood can be used outdoors by regular inspections and replacement of decayed parts, but not only wasting valuable wood resources but also a lot of time and money for inspection and maintenance. Maintenance costs. If the decay of wood is delayed and the outdoor life can be extended to about 10 years, the maintenance time and cost can be reduced, and further expansion of the wood utilization market can be expected.

  Wood decays because it itself becomes a nutrient source for wood-rotting fungi. As a general method for preventing this, a technique of applying or injecting a preservative to wood is used. In other words, the aim is for wood to lose its function as a nutrient source by impregnating with poisons for wood-rotting fungi. If wood that has been applied or injected with a predetermined amount of low-toxic organic synthetic compound-based wood preservatives that have been widely used in recent years is used as a grounding location, it is generally possible to use wooden civil engineering materials without replacing parts for over 15 years. It can be used.

  Moreover, it is also considered that microorganisms parasitic on wood decay fungi are attached to wood instead of preservatives to prevent decay. As a specific example, for example, Non-Patent Document 1 reports that by inoculating Trichoderma spp. On a piece of wood to be protected and culturing, the piece of wood becomes less susceptible to decay by wood-rotting fungi such as Prunus serrata and Kawaratake. ing. However, it is shown that the anti-corrosion effect varies depending on the strain of Trichoderma spp. Used, and that the anti-corrosion inhibitory effect against Kawaratake is weak. In addition, if a piece of wood inoculated with Trichoderma is heat-treated and sterilized, the antiseptic effect can hardly be expected, so it is essential that the Trichoderma spp. It is concluded that there is. However, there have been no concrete and practical technical proposals utilizing the principle to date.

  Patent Document 1 proposes to disperse spores of Trichoderma spp. On the roots of trees and the above-ground parts as a method for preventing basidiomycetes (Kaimendake, Bekkodake, Narratake, etc.) causing withering from infecting trees. Yes. However, this technique prevents the disease of growing trees and does not attempt to control the attack of wood-rotting fungi on the wood.

  By selecting the Trichoderma spp. Which are highly aggressive to Prunus serrata and Kawaratake, inoculating them on the support material and cultivating them, covering the periphery of the wood pieces to be protected with immobilized Trichoderma, the study to delay the decay of the wood pieces Attempts have already been made, for example, disclosed in Non-Patent Document 2 and Non-Patent Document 3. According to these documents, the anti-corrosion effect of the immobilized Trichoderma wood pieces has a stable effect against Prunus edulis, but is unstable to Kawaratake as with Non-Patent Document 1. It has become. In other words, when wood chips were exposed to Prunus edulis for 25 weeks at 25 ° C, the wood pieces had a weight loss rate of about 70%, and when immobilized Trichoderma and wood pieces were exposed together with Prunus edulis, the weight reduction rate of the wood pieces was about It is suppressed to 3%. On the other hand, when wood chips were exposed to Kawaratake at 25 ° C for 12 weeks, a 60% to 70% weight loss rate was produced on the wood pieces. When immobilized Trichoderma and wood pieces were exposed together with Kawaratake, the weight loss rate of the wood pieces was 4 to 16%.

In addition, Non-Patent Documents 2 and 3 use a pulverized wood having a pH of 4.3 (acidic) that has been heat-treated at about 240 ° C. as a support material for immobilizing Trichoderma spp. This is because common fungi such as Trichoderma spp. Prefer acidic environments and grow vigorously on their support materials. This heat-treated wood pulverized product having an acidic pH is used in the production of a greening material in which ectomycorrhizal fungi, VA mycorrhizal fungi and ericoidal mycorrhizal fungi, which are friends of mold in Patent Document 2, are immobilized. It is the same commercial product that was sold under the trade name of Misono Nare ^TM by Takeuchi Wood Industry Co., Ltd. in Higashikawa-cho, Kamikawa, Hokkaido, according to the manufacturing method of Japanese Patent No. 3057561.

It is reasonable to try to immobilize microorganisms on materials that have a pH preferred by microorganisms. However, acidic heat-treated wood is a special product. Since Takeuchi Wood Industry Co., Ltd. ceased production and sales activities in 2008, Misono Nare ^TM is currently not commercially available and is not available. The situation is possible. General charcoal is obtained by carbonizing wood at a temperature of about 400 ° C. or higher, and has a pH of about 9 or higher. Acidic charcoal cannot be made unless soaked with a strong acid solution such as hydrochloric acid or sulfuric acid.

  In patent document 3, what fixed | immobilized the bacteria of the genus Bacillus to the carbide | carbonized_materials, such as a timber, rice husk, and papermaking sludge, is used for the microbial material for agriculture or the microbial material for environmental purification. Bacteria including Bacillus are generally microorganisms that prefer neutral to slightly alkaline, but it is necessary to wash with running water until the pH of the carbide used is 7.45 or less is doing.

  Patent Document 4 proposes a mixture of Trichoderma spp. And its nutrient sources as a soil disease control agent for plant cultivation. In addition to rice husk, bran, rice bran, etc., nutrient sources include charcoal, kun charcoal, bark charcoal, rice husk kun charcoal, grass charcoal, activated charcoal and other various charcoal. And it is specified that sodium lactate, lactic acid, propionic acid, citric acid, DL-malic acid and the like are suitable as the pH adjuster of the soil disease control agent. Most of the pH adjusters are organic acids, and are intended to acidify the soil disease control agent when various charcoal is used as a nutrient source for Trichoderma spp.

  In Patent Document 5, in order to produce β-glucosidase having high enzyme activity, the Penicillium pinophilum Y-02 strain, which is a kind of Penicillium genus, or a mutant strain thereof is used as an inorganic material such as granular activated carbon, charcoal, zeolite, and polyurethane. It has been proposed to be used by immobilizing it on resin (polymer) materials such as agar. Although no specific method is described for the immobilization method, it describes that any of the general immobilization methods, the entrapment method, the physical adsorption method, and the covalent bond method may be used. For mediums that produce β-glucosidase in immobilized Y-02 strains, etc., in addition to various carbon sources, nitrogen sources, inorganic salts, natural nutrient sources such as peptone, and those containing a pH buffer The composition is not particularly limited. However, it is recommended and specified that the pH should be an acidic condition of 0 to less than 7. Since the activity of the Y-02 strain and its mutants is maintained by maintaining the acidic conditions, there is an aim to suppress the propagation of miscellaneous bacteria that enter the reaction system in addition to improving the productivity of the target product.

  Patent Document 5 describes that the Y-02 strain was cultured on a Czapek yeast agar medium or malto extract agar medium, and its microbial flora was observed. These media are usually used for the identification of filamentous fungi with emphasis on morphological observation. In this patent document, it is confirmed that the Y-02 strain grown on these media is a Penicillium sp. Furthermore, the observation results of the detailed characteristics of the conidia pattern, phialide, and conidia are described.

  In the homepage of Arcnet Co., Ltd. shown in Non-Patent Document 4, the company's product, which is a mixture of Trichoderma spp. And activated carbon produced from corn core, functions as a soil conditioner with excellent properties such as preventing continuous cropping failures. Is shown. In addition, since the action of Trichoderma spp. Is slow at a pH of 8.0 or higher, 5% of a 200-fold diluted solution of wood vinegar is mixed in the activated carbon produced from the corn core. Wood vinegar is an acidic liquid produced as a by-product when charcoal is produced. By using the same solution, the pH of the activated carbon produced from the core of corn is adjusted in the acidic direction to prevent the activity of Trichoderma spp.

  The reason why heat-treated products and carbides are used as the supporting material for microorganisms is that they can be found to be of great value because they are heated at a temperature exceeding 100 ° C. and are in a sterile state. There is almost no miscellaneous bacteria that inhibit the immobilization of Trichoderma bacteria, and it is possible to save labor and energy consumption for sterilizing the support material.

JP-A-9-249513 JP 2007-74986 A JP 2002-360244 A JP 2004-137239 A JP 2010-187603 A

Shuichi Doi, Satoshi Yamada, Trichoderma to prevent wood decay, Forest Products Laboratory Report, Vol. 1992, Vol. 2, No. 1-5 Togashi, Sadayuki Miyazaki, Kazuma Abe, Masashi Higashi, Yuichi Kuroda, Inhibitory activity and weather resistance against wood decay of immobilized Trichoderma, Proceedings of the Hokkaido Branch of the Wood Society of Japan, 2009, 41, 11-12 Onodera Ai, Kinoshita Shunsuke, Inhibitory activity of immobilized Trichoderma on the wood degradation reaction of wild basidiomycetes, 2010 Asahikawa National College of Technology Department of Chemical Engineering (2009), 1-16 Homepage URL of Arcnet Co., Ltd. (Morioka City, Iwate Prefecture), [online], [October 28, 2010 search], Internet <http: // www. arcnetjapan. co. jp / corncob / index. php>

As described above, research for preventing or delaying decay of wood using Trichoderma spp. Or immobilized Trichoderma has been conducted in the past, but in order to put it to practical use, it is necessary to further solve the following problems. is there.
(1) Establishing a method for selecting Trichoderma spp. Excellent in inhibitory activity against not only Prunus communis but also Kawatake.
(2) In the case of immobilizing Trichoderma spp., The selected Trichoderma spp. Should be able to grow, and it is necessary to use a support material that is aseptic or nearly aseptic.
(3) Desirably, the supporting material has a function to further enhance the ability of the selected genus Trichoderma, and can be easily and inexpensively obtained in any region.
(4) Immobilized Trichoderma must have the ability to keep the weight loss rate of wood caused by Ootake and Kawaratake as close to zero as possible.

  The present invention has been made in view of the above-described circumstances, and can reliably select excellent strains from the collected Trichoderma spp., And further draw out the performance of Trichoderma spp. And is inexpensive and easily available. It is an object of the present invention to provide a method for producing an immobilized Trichoderma that can be fixed on a support material and has excellent practicality, and a method for preserving wood.

In order to solve the above problems, the present invention produces an immobilized Trichoderma by the following method.
(1) As an easily available and inexpensive support material, the most important point is that it is aseptic or nearly aseptic, and general charcoal or pulverized charcoal is used.
(2) Since charcoal is alkaline having a pH of about 9 or more, when charcoal is inoculated with Trichoderma spp., The growth of the bacteria that generally prefer acidity is poor. Therefore, a Trichoderma genus liquid inoculum pre-cultured in a liquid medium, for example, about 2 W / V% of a malto extract, is spread over a whole amount of charcoal or pulverized charcoal, and then cultured again. In this way, Trichoderma spp. Are habituated to the living environment on charcoal to promote immobilization. Specific numerical values such as the culture solution composition and pre-culture conditions of Trichoderma sp., The amount of Trichoderma sp. Sprinkled on charcoal, and re-culture conditions are shown in the following examples.
(3) Trichoderma genus that exhibits performance exceeding the wood decay inhibitory activity of immobilized Trichoderma using acidic heat-treated wood pulverized product by immobilizing Trichoderma spp. Select bacteria.

  By using the methods of the present invention of (1) to (3), it is possible to produce an immobilized Trichoderma that is available everywhere and has high wood decay inhibiting performance with reduced production cost.

  For the obtained immobilized Trichoderma, the wood pieces to be protected are covered with the Trichoderma to strongly inhibit the decay of wood by Ootake and Kawaratake, and the weight reduction rate of the wood pieces after exposure at 25 ° C for 12 weeks (the dry weight before exposure). It is possible to have a performance of suppressing the dry weight reduction rate after exposure to 100 or a value close to zero.

  According to the present invention, immobilized Trichoderma prepared by inoculating and cultivating selected Trichoderma spp. On charcoal or charcoal pulverized material, and placing them so as to surround the pieces of wood and wood to be protected, is used. Moreover, it becomes possible to strongly inhibit wood decay by Kawaratake. As a result, the use of wood as a civil engineering material can be expanded and the need for wood preservation technology that does not rely on preservatives can be met.

It is explanatory drawing of the microbial cell of the genus Trichoderma fix | immobilized by the charcoal ground material by embodiment of this invention. It is explanatory drawing of the performance evaluation method of the fixed Trichoderma by embodiment of this invention. It is explanatory drawing of the utilization method of the fixed trichoderma with respect to wooden civil engineering material.

  Hereinafter, a method for producing an immobilized Trichoderma and a method for storing wood will be described with reference to the drawings.

First, an embodiment of a method for producing an immobilized Trichoderma will be described.
[Example]
Inoculated with a liquid inoculum of Trichoderma sp. A strain that had been pre-cultured with a 2 W / V% solution of malt extract at 25 ° C. for 2 days. In 1 ml of this liquid inoculum, about 5 mg of Trichoderma bacteria are contained in dry weight. The pH of the liquid inoculum is about 5.2. A commercially available charcoal pulverized product with a water content of about 10 W / W% (pH = 9.2) is inoculated with a liquid inoculum of about 0.4 by volume, and cultured at 25 ° C. for 2 weeks to prepare immobilized Trichoderma did. FIG. 1 shows a stereomicrograph of the surface of the immobilized Trichoderma. The circles in the A part of FIG. 1 are spores of the genus Trichoderma. The cells of Trichoderma spp. Are fixed on the charcoal pulverized material 2 which is the support material.

  FIG. 2 shows the performance evaluation environment of the immobilized Trichoderma. As a flora 4 of wood-rotting fungi, Ozu Ratake FFPRI 0507 and Kawaratake FFPRI 1030 specified by the performance test and performance standard of wood preservation agent of JIS K 1571 were grown on potato dextrose agar medium (PDA medium) 5. Then, 4 × 5 × 25 mm white birch wood pieces 3 were exposed at 25 ° C. for 12 weeks on the bacterial flora 4 as a control group. As shown in FIG. 2, the wood piece 3 covered with the pulverized charcoal 2 in the control zone was defined as the charcoal zone, and the wood piece 3 covered in the control zone with the immobilized Trichoderma 1 was designated as the immobilized Trichoderma zone. The amount of charcoal pulverized product 2 and immobilized Trichoderma 1 used was about 10 ml per piece of wood. After exposure for 12 weeks, the birch wood piece 3 was taken out and dried at 60 ° C. for 48 hours, and the weight was measured. Table 1 shows the weight reduction rate caused by decay for 12 weeks, assuming the dry weight of the same piece of wood before exposure as 100. All values are average values of 12 pieces of wood. For the immobilized Trichoderma section, the test was repeated four times in the same manner, and variations were observed. As a result, the decay of the woodpecker and Kawaratake was stably inhibited, and the weight loss rate of the wood chip decreased to single digits.

  The weight reduction rate of the wood pieces in the control zone and the charcoal zone where no immobilized Trichoderma was used was as high as 50 to 70%, and the decay of the wood pieces had progressed in both test zones. The reason why the weight reduction rate of the piece of wood in the charcoal area is lower than that in the control area is that the charcoal has some effect on both wood decay fungi, but does not cause the inhibition of decay at the level of immobilized Trichoderma.

[Comparative example]
For reference, the weight reduction rate of white birch wood in the control group not using immobilized Trichoderma, as disclosed in Non-Patent Documents 2 and 3, and fixation using acid heat-treated wood pulverized product and Trichoderma sp. Table 2 shows the weight reduction rate of birch wood pieces in the Trichoderma district. Both are the results of exposure to both wood decay fungi at 25 ° C. for 12 weeks in the same manner. It can be seen that the anti-rotation effect on Prunus edulis is expected, but the anti-rotation effect on Pleurotus communis is unstable.

Next, the wood preservation method using the immobilized Trichoderma will be described.
The immobilized Trichoderma 1 in which Trichoderma spp. Are fixed on the support material in a living state by the method of the above embodiment is manufactured, and as shown in FIG. 3, the grounding point of the wooden civil engineering material 20 installed outdoors is produced. B is arranged with a thickness and width of about 5 centimeters or more around the ground circumference of the material 20 without a gap. As a result, the wood decaying fungi that invade the ground contact point of the wooden civil engineering material 20 and attack are attacked by the Trichoderma spp. Of the immobilized Trichoderma 1.

  In addition, as a method of invading wood decaying fungi, the spores released from the fruiting bodies or thick film spores separated by enlarging part of the mycelium fly in the air and adhere to the wood etc. It is common for germination to begin when there is a sufficient amount of water. In order to inhibit the germination of adhering wood-rotting fungi spores and the activity of mycelium after germination, which has come to and near the ground contact point of the wooden civil engineering material, the immobilized Trichoderma should be used to the extent that there is no gap around the ground of the material. It is necessary to consider the arrangement with a thickness of.

  Trichoderma spp. That have the characteristics of parasitic on wood decay fungi inhibit the germination of wood decay fungi spores and inhibit the growth of germinated mycelium. As a result, the degradation activity of the wood by the wood decay fungi is braked, and the decay of the wood can be greatly delayed even if it does not stop completely.

  According to the method for producing immobilized Trichoderma according to the present embodiment, it is possible to reduce the weight loss rate of wood pieces and wood after exposure for 12 weeks at 25 ° C. to several percent. Charcoal is a low-cost and easy-to-use general material that is practical as a support material for Trichoderma spp. And is more stable against Kawaratake compared to immobilized Trichoderma using acid heat-treated wood pulverized material It is possible to exert the activity of inhibiting wood decay.

1 Immobilized Trichoderma 2 Charcoal pulverized product 3 Birch wood fragment 4 Microflora of wood-rotting fungi
5 Potato dextrose agar medium (PDA medium)
10 Glass culture bottle 20 Wooden civil engineering materials

Claims (4)

A method for producing immobilized Trichoderma, characterized by inoculating alkaline charcoal or pulverized charcoal with live Trichoderma spp., Culturing and fixing it in a living state. 2. The method for producing an immobilized Trichoderma according to claim 1, wherein a Trichoderma genus liquid inoculum pre-cultured in a culture solution of about 2 W / V% of malto extract is prepared, and the Trichoderma genus liquid inoculum is used as the charcoal or the charcoal. A method for producing an immobilized Trichoderma, wherein a sufficient amount of the pulverized material is sprayed on the whole and then cultured again. The method for producing an immobilized Trichoderma according to claim 1 or 2, wherein Aspergillus spp. Is used. Delaying the decay of ground contact points of wooden civil engineering materials by placing the fixed Trichoderma manufactured by the method according to any one of claims 1 to 3 at the ground contact points of wooden civil engineering materials installed outdoors. Wood preservation method characterized by.