JPH07124543A - Purification of polluted soil using highly water-absorbent polymer - Google Patents

Abstract

PURPOSE:To hold the number of charged bacteria or the decomposition activity of pollutants to a good state by protecting charged bacteria from the predation due to a protozoan by charging bacteria for purifying soil pollutants to polluted soil in a state held to a carrier containing a highly water-absorbable polymer. CONSTITUTION:In the purification of polluted soil, bacteria are supported on a carrier containing a highly water-absorbable polymer to be charged to soil. By this method, moisture is properly supplied to charged bacteria and these bacteria are protected from the competition with indigenous bacteria and the predation due to soil bacteria and the decomposition activity of charged bacteria to pollutans (especially, volatile organochlorine compd. such as trichloroethylene) in soil is kept. As a carrier structure, porous materials are bonded to highly water-absorbable polymer particles 1 or highly water-absorbable polymer particles are interposed between the porous materials 2 as a binder. As bacteria, aerobic bacteria belonging to the genus Pseudomonas are pref. used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil purification method in which a microorganism having a capability of degrading soil pollutants for purification of soil pollutants is supported on a carrier having a superabsorbent polymer and administered to the soil.

[0002]

2. Description of the Related Art In recent years, various harmful persistent chemical substances have been detected in soil, rivers, sea, air, etc., and progress of pollution by these substances has become a problem. In particular, soil pollution due to organochlorine compounds has become a serious problem, and it is strongly desired to establish a technique for preventing the spread of pollution and regenerating the polluted environment. For example, soil pollution is a problem at gas manufacturing plant sites, refineries, oil refinery sites, fuel base sites, pulp factory sites, etc., and there is a great need for soil remediation methods to purify these contaminated soils. .

Further, soil pollution not only hinders the reuse of land, but also has a high risk of causing the expansion of the contaminated area due to the pollutants flowing into groundwater and diffusing. Is strongly requested.

Various methods have been known and tried as soil restoration methods for restoring soil to its original state by removing pollutants from polluted soil.

For example, there is a physicochemical method such as a vacuum extraction method for sucking pollutants from the soil. However,
Physicochemical methods have many problems, such as high cost, low operability, and difficulty in treating pollutants present in low concentrations.

Under these circumstances, expectations for a soil remediation method using microorganisms, so-called bioremediation, are increasing. As a method of utilizing microorganisms,
For example, from the one that enhances the self-cleaning ability of the ecosystem by degrading pollutants and detoxifying them by enhancing the function of microorganisms that naturally exist in the target soil, pollution as a way to take this technology one step further Attempts have been made, for example, to positively introduce bacteria having the ability to decompose substances into the contaminated soil from the outside to promote the repair of the contaminated soil.

[0007]

There are many known microorganisms capable of degrading pollutants detected in soil. However, even if such microorganisms are directly administered to the soil, the number of the microorganisms rapidly decreases in the soil within a short period of time, and the desired purification effect is often not obtained.

Therefore, in order to solve the problem of the decrease of microorganisms administered to the soil, a large amount of medium suitable for the growth of the administered microorganisms has been conventionally administered to the soil. Some people are worried about the possibility of secondary pollution caused by. Therefore, there is a demand for the development of a method for prolonging the survival of administered microorganisms in soil and maintaining the ability to treat pollution without requiring a large amount of medium to be added.

One of the important factors affecting the number of microorganisms administered to soil is the influence of soil water content on microorganisms. Soil shows various water contents depending on the area where the soil is located, topography, vegetation, depth, composition, etc. in the soil, which has a great influence on the physiological activity of microorganisms growing in the soil. Is no exception.

If the water content of the soil, to be precise, the water content available to the microorganism deviates from the value suitable for the microorganism, the administered microorganism often cannot obtain good growth and activity. That is, in general, the activity of microorganisms decreases when the water content of the surrounding environment becomes insufficient, and in the case of degrading microorganisms, the rate of degradation decreases. If the water shortage further progresses, microorganisms that are not drought-resistant will decrease and die, and even drought-resistant microorganisms will have extremely reduced activity such as forming spores, or will be dormant, and will It becomes impossible to expect disassembly. Further, contrary to the dry state as described above, when the water content in the environment becomes excessive, the oxygen concentration in the liquid becomes insufficient, and when the administered microorganism is aerobic, it becomes a disadvantageous environment for the microorganism, A decrease in activity and a decrease in the number of bacteria occur. In particular, since many microorganisms having a high activity of decomposing pollutants are aerobic, such an oxygen-deficient state is often not preferable.

Another cause of reduction of microorganisms in soil is competition with microorganisms originally distributed in soil, especially predation of administered microorganisms by protozoa, and avoiding predation by protozoa. Is also required to improve the survival of the administered microorganisms.

On the other hand, in bioremediation, in addition to the above-mentioned improvement of survival of microorganisms, there is a problem of how to efficiently diffuse the administered microorganisms into the soil. Bioremediation targets low-concentration and wide-range contaminated areas that could not be treated by physicochemical methods such as vacuum extraction, but in order to actually purify such soil, degrading microorganisms are a prerequisite for contaminated soil. It is necessary to diffuse in. However, the movement of microorganisms in soil is not easy, and the development of a method for allowing microorganisms to reach the vicinity of soil in which harmful substances are present has been an issue. The method of injecting degrading microorganisms into soil using water, air, etc., the method of administering a large amount of degrading microorganisms to soil, etc. are currently adopted as the diffusion method of degrading microorganisms in soil. Microbial diffusivity is significantly reduced depending on the type of soil, such as high soil or low water content soil. Therefore, a method other than the current method is required.

The object of the present invention is to provide a suitable water supply to the microorganisms administered to the soil, protect the administered microorganisms from predation by protozoa, etc., and maintain the number of administered microorganisms and the activity of decomposing pollutants in good condition. To provide a purification method.

Another object of the present invention is to provide a soil remediation method capable of effectively diffusing microorganisms in a contaminated area of soil.

[0015]

Means for Solving the Problems The soil purification method of the present invention, which can achieve the above-mentioned objects, comprises a microorganism for purification of soil pollutants,
It is held in a super absorbent polymer carrier and administered to contaminated soil,
It is characterized in that the contaminated soil is purified.

In the method of the present invention, a carrier is used to hold the microorganisms to be administered to the soil so that the microorganisms to be administered are appropriately supplied with water, and the microorganisms to be administered are prevented from competing with the indigenous microorganisms and predation by the soil microorganisms. It protects and maintains the activity of the administered microorganisms to decompose pollutants in the soil.The superabsorbent polymer is used as a carrier to hold the microorganisms, which ensures the proper supply of water to the retained microorganisms. It will be

This highly water-absorbent polymer is a polymer having the ability to absorb and retain several tens to several hundreds of water of its own weight without dissolving in water. It has an ionic group that has a high affinity for water, and has a structure in which the polymer molecular chain is crosslinked and insolubilized so as not to diffuse and dissolve in water.

As the highly water-absorbent polymer for constituting the carrier used in the method of the present invention, one having high gel strength and excellent salt resistance is desirable in consideration of the situation of use by putting it into soil. What is used in the agricultural and horticultural field can be used. Specifically, starch-
Acrylonitrile graft polymer hydrolyzate, starch-acrylic acid graft polymer, starch-styrene sulfonic acid graft polymer, starch-vinyl sulfonic acid graft polymer, starch-acrylamide graft polymer, cellulose-acrylonitrile graft polymer, cellulose- Styrene sulfonic acid graft polymer, carboxymethyl cellulose cross-linked product, hyaluronic acid, agarose, polyvinyl alcohol cross-linked polymer, sodium polyacrylate cross-linked product, sodium acrylate-vinyl alcohol copolymer, saponified polyacrylonitrile polymer and the like. Can be one of these, or two
A combination of two or more species can be used.

When the super absorbent polymer is used alone, it can be used in various forms such as powder, powder, fine powder, pearl, beads, flakes and blocks, and the particle size is several. It is preferably 100 μm to several mm.

The superabsorbent polymer is obtained by polymerizing a hydrophilic monomer (which may be a hydrophobized hydrophobic monomer) and crosslinking the obtained polymer, or by crosslinking the polymer obtained by the polymerization. It can be produced by a method of making hydrophilic. As the polymer hydrophilization treatment, polymer preparation by polymerizing a hydrophilic group-containing monomer,
Methods such as introduction of a hydrophilic group into the polymer, grafting of the polymer with a hydrophilic group-containing monomer, grafting of the polymer with a hydrophilic group-containing polymer, saponification or hydrolysis treatment of the polymer can be used. Further, as a cross-linking / insolubilizing treatment of a polymer obtained by polymerizing a hydrophilic monomer, reticulation by a cross-linking agent, reticulation by introducing a cross-linking monomer, reticulation by self-crosslinking, reticulation by light / radiation irradiation, hydrophobic treatment Insolubilization due to the copolymerization of hydrophilic monomers
There are methods such as insolubilization by introducing a crystalline polymer block and cross-linking with a polyvalent metal ion.

The carrier used in the method of the present invention may be a carrier further containing a porous material capable of retaining microorganisms. As such a porous body, for example, a porous body capable of forming a microhabitat of microorganisms is preferable. An example of the structure of a carrier when a porous body is used in combination is shown in FIG.
It is schematically shown in (d). FIGS. 1 (a) and 1 (b) show the structure of a carrier prepared by mixing and stirring a superabsorbent polymer and a porous body, and FIG. 1 (a) shows a porous body attached to superabsorbent polymer particles. FIG. 1 (b) shows a structure in which a super absorbent polymer is present as a binder in the gap between the porous bodies to form these aggregates. FIG. 1 (c) shows a carrier in which a porous layer is formed on the surface of a super absorbent polymer.
(D) is a carrier having a structure in which a porous body is embedded in the superabsorbent polymer surface layer. These carriers can be obtained, for example, by selecting the granulation conditions for forming granules made of the superabsorbent polymer, the materials of the superabsorbent polymer and the porous material, the mixing ratio, and the like. The shape is mainly granular or block-shaped,
The minimum size is about 500 μm, the maximum is 2 to 3 cm, and the average size is about 1 to 5 mm.

The micro habitat is a minute residence of microorganisms in pores of about several μm and has a function of protecting the microorganisms from a harsh external environment. For example, even if the outside of the pores is in a dry state where it affects the survival of the microorganisms, the water supply to the microorganisms is maintained because the capillary water is retained in the microhabitat. Microorganisms in the microhabitat can also avoid predation by protozoa in the soil. By artificially forming a microhabitat of the microorganism to be administered in a carrier and administering this carrier into the soil, the survival of the microorganism can be improved. Furthermore, by making the carrier into a form suitable for diffusion in the soil, it becomes possible to effectively disperse the administered microorganisms in the soil.

The porous body can be used in various forms such as granular form and layer form. Examples thereof include ceramics, glass,
Inorganic materials such as soil particles with aggregate structure such as calcium silicate, silica, Kanuma soil, activated carbon, urethane foam, anion exchange resin, cellulose, lignin,
One of the porous materials made of organic materials such as chitin and chitosan
It is possible to use one species or a combination of two or more species. As the porous body, an inexpensive one is preferable in consideration of large-scale administration into soil.

As a method for producing a carrier containing a porous material, for example, a superabsorbent polymer powder before water absorption is mixed with a porous material carrying desired microorganisms, and an appropriate amount is added with gentle stirring. Pour water or culture medium. When the microorganisms are also held at the same time, the microbial cells may be suspended in the water or the medium injected. Of course, in order to increase the amount of the microorganisms adsorbed and retained on the porous body, the microorganisms may be adsorbed and acclimated to the porous body in advance and then mixed with the superabsorbent polymer. When a mixture of superabsorbent polymer and porous material is sprayed on the soil in such a configuration, the superabsorbent polymer while the porous material has a contact surface with the external soil depends on the spray amount per soil volume. It is in a state of being accompanied by.

When it is required to configure both of them more strictly than the above-mentioned production method, the granulation is performed so that a layer of the porous body is formed on a part or the whole of the periphery of the superabsorbent polymer carrier. And a method of granulating so that the porous body is embedded in the surface of the superabsorbent polymer carrier so as to be rarely used.

The type of the porous material is not particularly limited, but it is preferable that the mobility or dispersibility of the carrier in the soil is not impaired, and for example, a particulate material having a particle diameter of about several hundred μm to several mm is desirable. . Further, those having a structure and properties suitable for adsorption and growth of microorganisms, for example, a porous body having a pore size of several μm to several tens of μm, or a porous body having an ion exchange group on the surface and excellent in ion adsorption property Is preferred.

When such superabsorbent polymer absorbs water and retains the microorganisms, the retained microorganisms retain the microorganisms in the soil even if the soil to be purified has a low moisture content. It is possible to maintain viability, proliferative activity, and degradative activity without being exposed to a water environment.

Furthermore, by impregnating the superabsorbent polymer with a medium that promotes the growth of microorganisms instead of water, nutrients can be supplied together with the supply of water, particularly when the contaminated soil is oligotrophic, to promote the activity of microorganisms. Show the effect. In addition, some microorganisms that decompose harmful substances require the coexistence of other substances called inducers in order to decompose the harmful substances. For example, some Pseudomonas bacteria known as trichlorethylene-degrading bacteria often require the presence of aromatic organic compounds as inducers for the degradation of trichlorethylene. In such a case, in order to maintain the decomposition of harmful substances, it is necessary for the inducer substance to be retained in the soil for a long period of time and to be continuously supplied to the decomposing microorganisms, in addition to survival of the microorganisms. Inducer substances are often used as nutrient sources by indigenous microorganisms in soil, and it is also difficult to make them locally present in the vicinity of degrading microorganisms. Therefore, if this inducer substance is impregnated with a superabsorbent polymer together with another medium, the inducer is constantly supplied to the degrading microorganisms without being utilized by the indigenous microorganisms, and the degrading activity of the microorganisms is maintained.

Contrary to the soil having a low water content as described above, when the water content of the contaminated soil is very high (when the maximum amount of dissolved water is 90% or more), the oxygen concentration in the soil decreases. However, it has been a problem that the activity of aerobic degrading bacteria is extremely reduced. However, if such a water-absorptive superabsorbent polymer retaining aerobic degrading bacteria is administered, the superabsorbent polymer will have excessive water content. It is possible to supply oxygen to the retained microorganisms by forming a gas phase space around the polymer by improving the air permeability by absorbing the oxygen.

The action of removing excess water in the soil while supplying water to the microorganisms retained by the superabsorbent polymer and further to the microorganisms detached from the polymer by growth is the predation of the degraded microorganisms by the protozoa. It is also effective in avoiding. The movement of protozoa in soil is mainly mediated by soil moisture, and is largely influenced by soil water content. For example, the genus Colpoda, which is a representative of protozoa that prey on bacteria, has a maximum water capacity of 60%.
In the following soils, migration is extremely limited and the amount of bacterial predation is small, but when the maximum water capacity is 80% or more, migration in soil becomes active and it is known that bacteria are actively predated ( Ronald Vargas, Tsutom
u Hattori: FEMS Microbiolo
gy Ecology 38 (1986) 233-24
2).

Therefore, by reducing the water content in the soil used by the protozoa for migration by using a superabsorbent polymer which does not hinder the utilization of the degrading microorganisms, the migration of the protozoa is restricted and the microbial predation is restricted. The amount can be reduced and the viability of degrading microorganisms can be increased.

Further, the superabsorbent polymer does not unilaterally perform the functions of absorbing water in the soil and supplying (slowly releasing) water into the soil, but absorbs water depending on the water content in the soil. It also has the function of repeating the sustained release cycle.
Therefore, it is possible to promote the decomposition of low-concentration pollutants in soil having a low water content, which has been difficult to treat by the following method. That is, a superabsorbent polymer in an unabsorbed state in which degrading microorganisms are retained is administered to contaminated soil, and then water or a medium is injected into the soil while considering the water content of the soil. Injected water and medium in which trace amounts of harmful substances are dissolved are gradually absorbed by the superabsorbent polymer that has been administered, and are collected in the vicinity of degrading microorganisms. At this time, some harmful substances are decomposed by microorganisms. The water absorbed by the superabsorbent polymer is gradually released when the soil water content, which has been raised to some extent by the injected water or the culture medium, decreases over time. Also at this time, the harmful substances in the released solution are decomposed by the microorganisms. After a certain period of time when the water content of the superabsorbent polymer has decreased, water or medium is injected again to dissolve the trace amount of the harmful substances that still remain in the liquid and absorb it into the superabsorbent polymer. By doing so, the microorganisms are similarly decomposed. By repeating this, the soil having a low water content in which pollutants are present in a low concentration is efficiently purified. Unlike the conventional bioremediation method, this method collects microorganisms in the vicinity of harmful substances that are diffused in the soil, while moving the harmful substances in the soil by using the water absorption capacity of the superabsorbent polymer as a power source. It is characterized by collecting harmful substances in the vicinity of the degrading microorganisms. According to this method, soil in which microorganisms are difficult to diffuse,
For example, soil with a high clay content is relatively easy to purify.
The method of injecting water or medium may be the same as the conventionally used method.

The superabsorbent polymer is used as an immobilizing carrier in a closed system such as a bioreactor for the purpose of improving the treatment capacity of microorganisms. In this case, a crosslinking method,
There is a demand for an immobilization method, such as an encapsulation method, in which microorganisms are not detached from the carrier. On the other hand, as the function of the superabsorbent polymer used in the present invention, the main purpose is to maintain the survival and activity of the microorganisms retained by adjusting the water content in the soil environment, and then to proliferate. It is expected that microorganisms desorbed from the superabsorbent polymer will diffuse into the soil as widely as possible, actively contact with pollutants, and decompose. For this reason, immobilization methods such as those used in closed systems are not compatible with this purpose, and in order for the proliferated microorganisms to be released to the outside, the retained microorganisms must be on the surface of the superabsorbent polymer or the superabsorbent polymer. It is required to be adsorbed on the surface of the carrier that is complexed with the water-soluble polymer. The present invention meets this requirement.

Although the method of the present invention has a method that is partially suitable for aerobic bacteria, it can be generally applied to any kind of microorganisms, and depending on the characteristics of the contaminant to be removed, the microbial species and A super absorbent polymer and a carrier can be appropriately selected.

As the microorganisms to be administered, those already isolated, those newly screened from the soil or the like according to the purpose can be used, and a mixed system of plural kinds of microorganisms may be used.

The soil purifying treatment can be performed by administering the soil purifying agent having the above constitution to the soil. The soil purifying agent can be applied to the soil by a conventional method such as spraying treatment or mixing treatment with soil. Further, for administration to a relatively deep portion of the soil, a method in which a drill hole is provided and a soil purifying agent is administered and dispersed from there can be used.

[0037]

EXAMPLES Examples will be shown below, but these do not limit the scope of the present invention.

Example 1 Effect of Superabsorbent Polymer on Survivability of Pseudomonas cepacia Pseudomonas cepac
iaKK01 (accession number; FERM BP-4235,
Date of deposit: On March 11, 1992, 10 ml of M9 + yeast extract medium (deposited at the Institute of Biotechnology, Institute of Biotechnology, Ministry of International Trade and Industry, under the Budapest Treaty) was added to M9 medium of the following composition. (05% yeast extract was added) and the cells were cultured at 30 ° C. M9 medium composition (in 1 liter of water); Na ₂ HPO ₄ ... 6.2 g KH ₂ PO ₄ ... 3.0 g NaCl ... 0.5 g NH ₄ Cl ... 1.0 g O. D. After (550 nm) reached about 0.7, 100 mg of cellulose fine powder carrier (Microcarrier manufactured by Asahi Kasei Corporation) was added to this solution, and the pressure was reduced in a pressure bottle to introduce bacteria into the micropores.

This cellulose fine powder carrier adsorbed by bacteria was mixed with 200 mg of a polyacrylic acid cross-linked superabsorbent polymer (Sunwet IM-5000D manufactured by Sanyo Chemical Industry Co., Ltd.), and stirred at 30 rpm with a stirrer (PR-300 manufactured by Fujiwara Seisakusho).
Add 20 ml of water little by little while gently stirring at
A carrier comprising a superabsorbent polymer / porous carrier composite was obtained. The obtained carrier had the structure shown in FIG. 1 (a), and the particle diameter of superabsorbent pomer particles was 3 to 4 mm.

[0040] The super absorbent polymer thus prepared
A carrier composed of a porous carrier complex was added to 100 g of unsterilized brown forest soil adjusted to have a water content ratio of 50% in a 500 ml beaker, mixed and covered with a filter paper (Whatman No. 44). At this time, the final water content of the soil was about 80%.
Fifteen similar products were prepared and allowed to stand in a constant temperature incubator at 30 ° C. On the 0th, 3rd, 7th, 10th, and 14th days after the start of the culture, P. The number of bacteria of cepacia was measured. The bacteria were counted by the dilution plate method using a phenol single carbon source agar medium. The experiment was performed in triplicate and the average number of bacteria was taken. The result is shown in FIG.

Comparative Example 1 P. cerevisiae obtained by the same method as in Example 1 cepaciaK
The cellulose carrier on which K01 was adsorbed was mixed with distilled water 20, and this was added and mixed with 100 g of unsterilized brown forest soil adjusted to a water content ratio of 50% in a 500 ml beaker, and filtered with a filter paper (Whatman No. 44). I covered it. At this time, the final water content of the soil was about 80%. Fifteen similar products were prepared and allowed to stand in a constant temperature incubator at 30 ° C. On the 0th, 3rd, 7th, 10th, and 14th days after the start of the culture, P. The number of bacteria of cepacia was measured. The bacteria were counted by the dilution plate method using a phenol single carbon source agar medium. The experiment was performed in triplicate and the average number of bacteria was taken. The result is shown in FIG.

Example 2 Effect of superabsorbent polymer on TCE degradability of Pseudomonas cepacia PSE degrading bacterium Pse using phenol as an inducer
Example 1 Udomonas cepacia KK01
10 ml of medium (0.05% yeast extract + M9
The medium was inoculated and cultured at 30 ° C. O. D.
(550 nm) reached about 0.7, 10 ml of M9 medium containing 200 ppm of phenol was added thereto, 100 mg of polyacrylic acid crosslinked superabsorbent polymer (Sunwet IM-5000D manufactured by Sanyo Chemical Industry Co., Ltd.) and a stirrer ( Fujiwara Seisakusho PR-300) was added with gentle stirring at 30 rpm to obtain a superabsorbent polymer carrier.

1 mg of TCE was added to the super absorbent polymer carrier.
1 to 50g of unsterilized brown forest soil containing 50% water
Add and mix in a 00 ml vial and seal with a silicone stopper. Fifteen similar products were prepared and allowed to stand in a constant temperature incubator at 30 ° C.

On the 0th, 1st, 2nd, 3rd, and 4th days after the start of culture, the TCE concentration in the gas phase of each vial was measured by the gas claw headspace method. The experiment was performed in triplicate and the TCE concentration was averaged. The result is shown in FIG.

Comparative Example 2 P. cerevisiae cultured in the same manner as in Example 2 cepaciaKK01
To 10 ml of the bacterial suspension of the strain was added 10 ml of M9 medium containing 200 ppm of phenol, and 200 pp of phenol was added to this.
10 ml of M9 medium containing m was added to the same soil as in Example 2, mixed and cultivated at 30 ° C. for 0 days, 1 day, 2 days.
On the 3rd and 4th days, the TCE concentration in the gas phase of each vial was measured by the gas claw headspace method. The experiment was performed in triplicate and the TCE concentration was averaged. The result is shown in FIG.

Example 3 Effect of superabsorbent polymer on survival of Escherichia coli Escherichia coli kanamycin and chloramphenicol resistance vector pUS0800 having the structure shown in FIG.
ichia coli HB10 was transformed by the calcium chloride method. LB medium (10 g of bactopeptone /
1, yeast extract 5 g / 1, sodium chloride 10 g / 1, pH 7.5) 10 ml and inoculated at 37 ° C. D. The culture was carried out with shaking until it reached about 0.7.

This culture solution and a polyacrylic acid crosslinked superabsorbent polymer (Sunwet IM-50 manufactured by Sanyo Kasei Co., Ltd.)
00D) 200 mg with a stirrer (PR-3 manufactured by Fujiwara Seisakusho)
00) was mixed with gentle stirring at 30 rpm to obtain a super absorbent polymer carrier.

Next, this superabsorbent polymer carrier was used to collect the bacterial predatory protozoan Colpodas isolated from soil.
p. To E. 10 ml of culture broth which was cultivated with chokeley salt solution using E. coli as the bait
⁴ pieces) and 100 g of sterilized brown forest soil whose water content was adjusted to 80% were added and mixed in a 500 ml beaker, and the lid was covered with filter paper (Whatman N.44). Similar one
Five pieces were prepared and left still in a constant temperature incubator at 30 ° C.

On the 0th, 1st, 2nd, 3rd, and 4th days after the start of culturing, the E. The number of E. coli bacteria was measured. The number of bacteria was determined by measuring the number of bacteria by the dilution plate method using nutrient agar containing kanamycin and chloramphenicol. The experiment was performed in triplicate and the average number of bacteria was taken. The result is shown in FIG.

Comparative Example 3 E. coli cultured in the same manner as in Example 3 was used. 10 ml of E.coli suspension
Was cultured in the same manner as in Example 3 to produce Colpoda.
sp. 500m per 100g soil with 10ml culture solution
The mixture was added and mixed in a 1-liter beaker and covered with a filter paper. Prepare 15 similar ones, incubate at 30 ℃, 0 day, 1
E. coli in the soil of each beaker on the 2nd, 3rd, 4th day. c
The number of oli bacteria was measured. The experiment was performed in triplicate and the average number of bacteria was taken. The result is shown in FIG.

[0051]

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to maintain the number of administered microorganisms in the soil by retaining the microorganisms in a carrier containing a superabsorbent polymer and administering the microorganisms to the soil. It becomes possible to secure good mobility or dispersibility of microorganisms.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a structure of a carrier of the present invention,
(A) is a superabsorbent polymer particle having a porous body attached thereto, (b) is a porous body having a superabsorbent polymer interposed as a binder to form these aggregates,
(C) shows a structure in which a porous body layer is formed on the surface of a super absorbent polymer, and (d) shows a structure in which a porous body is embedded in the super absorbent polymer surface layer.

FIG. 2 is a graph showing changes in the number of bacteria in the test soil obtained in Example 1 and Comparative Example 1.

FIG. 3 is a graph showing changes in the number of bacteria in the test soil obtained in Example 2 and Comparative Example 2.

FIG. 4 shows the structure of vector pUS0800.

FIG. 5 is a graph showing changes in the number of bacteria in the test soil obtained in Example 3 and Comparative Example 3.

Claims (12)

[Claims] 1. A microorganism for purifying soil pollutants is held in a carrier containing a superabsorbent polymer and administered to a polluted soil,
A soil purification method comprising purifying the contaminated soil. 2. The soil purification method according to claim 1, wherein the carrier has a portion made of a porous body and a portion made of the superabsorbent polymer. 3. The soil purification method according to claim 2, wherein the carrier has a structure in which the porous body is held on at least the surface of the superabsorbent polymer carrier. 4. The soil purification method according to claim 2, wherein the surface of the porous body has a layer of the water-absorbing polymer. 5. The soil purification method according to claim 1, wherein the microorganism is a bacterium. 6. The method according to claim 1, wherein the microorganism is an aerobic bacterium.
The soil purification method according to any one of 5 above. 7. The microorganism is Pseudomonas (Pseu).
The soil purification method according to claim 6, which is a bacterium belonging to the genus Domonas. 8. The soil purification method according to claim 7, wherein the microorganism is Pseudomonas cepacia. 9. The microorganism is Pseudomonas cepacia KK01.
The soil purification method according to claim 8, which is a strain. 10. The soil purification method according to claim 1, wherein the soil pollutant is a volatile organic chlorine compound. 11. The soil purification method according to claim 10, wherein the volatile organic chlorine compound is trichlorethylene. 12. The soil purification method according to claim 1, wherein decomposition of the soil pollutant is induced by an inducer substance.