JP2003275739A - Method for degrading metal cyano complex - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for degrading a metal cyano complex with high treatment ability in the technique to treat an objective material containing the metal cyano complex by using a microorganism having degrading performance for the metal cyano complex. <P>SOLUTION: The objective material containing the metal cyano complex is treated with acriflavin and further treated with the microorganism having resistance against acriflavin and capability for degrading the metal cyano complex. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for decomposing a metal cyano complex.

[0002]

2. Description of the Related Art Conventionally, in order to purify an object to be treated (for example, soil or groundwater) contaminated with a metal cyano complex,
Various methods of decomposing and removing the metal cyano complex have been proposed. Among them, metal cyano complexes with high chemical stability (for example, iron, cobalt, silver, and gold cyano complexes) were difficult to apply physical / chemical treatments. The application of bioremediation, which decomposes and purifies the object to be treated, has been noted.

[0003] Then, in order to carry out the bioremediation, a search for a microorganism capable of degrading the metal cyano complex was carried out, and a microorganism capable of degrading the metal cyano complex was isolated from nature. For example, as a microorganism capable of degrading the metal cyano complex, there is Klebsiella pneum.
oniae) AN-1 strain (FERM P-17792)
Is known (see Japanese Patent Laid-Open No. 2001-269166).

[0004]

However, when the microorganism having the metal cyano complex decomposing ability is used to decompose the metal cyano complex in the object to be treated, the resolving ability is actually low. It was sometimes suppressed. This causes a problem that the amount of the treatment object that can be treated is reduced or the period required for the treatment is extended, and further, the facility for treating the metal cyano complex is enlarged or the treatment is performed. This causes a problem of delay and increase in processing cost due to the delay.

Therefore, in view of the above-mentioned drawbacks, an object of the present invention is to decompose a metal cyano complex having a high processing ability in a technique of treating an object to be treated containing a metal cyano complex with a microorganism having a metal cyano complex decomposing ability. To provide a method.

[0006]

The first characteristic means of the method for decomposing a metal cyano complex of the present invention for achieving this object is as follows:
As described in claim 1, an object to be treated containing a metal cyano complex is subjected to acriflavin treatment and treated with a microorganism having acryflavin resistance and the metal cyano complex decomposing ability. Furthermore, in the above-mentioned first characteristic means,
As described in claim 2, it is preferable to add a nutrient that can be used by the microorganism. The second method of decomposing a metal cyano complex according to the present invention for achieving this object
As a characteristic means, as described in claim 3, an object to be treated containing a metal cyano complex is treated with an antibiotic, and treated with a Klebsiella bacterium having resistance to the antibiotic and the ability to decompose the metal cyano complex. In point. Further, in the second characteristic means, as described in claim 4, it is preferable to further add a nutrient that can be used by the Klebsiella genus bacterium. Further, in the first or second characteristic means, as described in claim 5, the object to be treated may be soil or groundwater, and one or both of them may be treated in situ. And these effects are as follows.

[0007] In order to solve the above-mentioned problems, the inventors of the present invention have explained the reason why the above-mentioned metal cyano complex decomposing ability of a microorganism having a metal cyano complex decomposing ability (hereinafter referred to as "metal cyano complex degrading microorganism") is not sufficiently exerted. Diligent research was conducted. In the course of this research, various factors were examined, and it was found that the metal cyano complex degrading ability of the metal cyano complex-degrading microorganism depends on the presence of coexisting microorganisms. That is, in the case where the metal cyano complex-degrading microorganism overlaps with another microorganism (hereinafter, referred to as "coexisting microorganism") in which the nutrients used for its growth and proliferation coexist, by competing with the coexisting microorganism, The inventors hypothesized that the growth / proliferation of the metal cyano complex-degrading microorganism was suppressed, and as a result, the metal cyano complex degrading ability was significantly reduced or disappeared as compared with the case of pure culture.

[0008] The inventors then added an antibiotic such as acriflavine under the coexistence of the metal cyano complex-degrading microorganisms and the coexisting microorganisms so that the metal cyano complex-degrading microorganisms Klebsiella pneumoniae AN.
-1 strain (FERM P-17792) and the like, when the metal cyano complex was decomposed, it was found that the metal cyano complex decomposing ability was significantly improved, and the present invention was completed.

That is, as described in claim 1,
By treating the object to be treated containing the metal cyano complex with acriflavine, it is possible to kill or reduce the acriflavin-sensitive microorganism among the coexisting microorganisms. Therefore, the interference caused by the coexisting microorganisms is significantly reduced. Then, after or at the same time as the acriflavine treatment, when the object to be treated is treated with a microorganism having both acryflavin resistance and the metal cyano complex decomposing ability, the metal cyano complex degrading microorganism not affected by the acriflavine, It preferentially grows and propagates in the system that treats the object to be treated. Therefore, the decomposition of the metal cyano complex by the metal cyano complex-decomposing microorganism can be efficiently performed. Here, the processing target is
It exists in various forms such as solid, liquid, and gel, and is not particularly limited, and examples thereof include soil containing the metal cyano complex, groundwater, seepage water in landfill, industrial waste, and the like. To be In addition, acriflavine (chemical formula C ₁₄ H
₁₄ ClN ₃ ) is a compound having a structure represented by the following chemical formula 1, and in the present application, it also includes an acriflavine derivative / analog compound (for example, acriflavine hydrochloride) capable of eliminating the coexisting microorganisms. Let's assume.

[0010]

[Chemical 1]

Further, in the first characteristic means, as described in claim 2, when a nutrient usable by the metal cyano complex-degrading microorganism is added before or at the same time as the treatment with the microorganism, the acriflavin content is increased. Since the coexisting microorganism competing by the action is killed or reduced, the metal cyano complex-degrading microorganism can preferentially utilize the nutrient. As a result, the growth / proliferation of the metal cyano complex-decomposing microorganism is promoted, and the metal cyano complex-decomposing microorganism efficiently decomposes the metal cyano complex. Here, the nutrient is an organic substance or an inorganic substance, or a mixture thereof, and it is preferable that the substance mainly used by the metal cyano complex-degrading microorganism is used as a main component. Based on that, the composition can be determined. For example, glucose, inositol, or the like can be used as the carbon source. In addition, a potassium source, a magnesium source, a phosphorus source, etc. can be added.

Alternatively, as described in claim 3, when the object to be treated containing the metal cyano complex is treated with an arbitrarily selected antibiotic, the antibiotic-sensitive microorganism among the coexisting microorganisms is killed. Or, since it can be reduced, the interference by the coexisting microorganisms is greatly reduced. Here, the antibiotic is of a type that the Klebsiella genus having the metal cyano complex decomposing ability has resistance, and after or simultaneously with the antibiotic treatment, the Klebsiella bacterium having the metal cyano complex decomposing ability is the treatment target. When the substance is treated, the Klebsiella bacterium that is not affected by the antibiotics preferentially grows and proliferates in the system that treats the subject. Therefore, the decomposition of the metal cyano complex by the Klebsiella bacterium can be efficiently performed. Here, when the Klebsiella bacterium is used for decomposing the metal cyano complex, the poorly soluble metal cyano complex (particularly iron cyano complex) is a weak alkaline (pH 7) which is a pH range in which it is easily dissolved in an aqueous solution.
~ 9.5), the removal rate of the metal cyano complex can be increased. The object to be treated is present in various forms such as solid, liquid and gel, and is not particularly limited, but for example, soil containing the metal cyano complex, groundwater, and landfill. Exuded water, industrial waste, etc. are mentioned. In addition, as an antibiotic, a Klebsiella bacterium having the above-mentioned metal cyano complex decomposing ability (for example, Klebsiella pneumoniae AN-1) is used.
It is not particularly limited as long as it has no bactericidal / bacteriostatic activity against a coexisting microorganism and has bactericidal / bacteriostatic activity against the coexisting microorganisms. For example, deoxycholic acid, brilliant green, cycloheximide and the like can be mentioned.

Further, in the second characteristic means, as described in claim 4, when a nutrient usable by the Klebsiella bacterium is added, the coexisting microorganism competing by the action of the antibiotic is killed or Decrease,
The Klebsiella bacteria can preferentially utilize the nutrients. As a result, the growth and proliferation of the Klebsiella bacterium is promoted, and the decomposition of the metal cyano complex by the Klebsiella bacterium is efficiently performed.
Here, the nutrients are organic substances, inorganic substances, or a mixture thereof, and it is preferable that the main component is a substance that is preferably used by the Klebsiella bacteria. For example, glucose, inositol, or the like can be used as the carbon source. In addition, a potassium source, a magnesium source, a phosphorus source, etc. can be added.

By the way, when the object to be treated is soil or groundwater and one or both of them are treated, the method for treating them in-situ (in-situ method) requires that a treatment facility is provided in another place. In addition, there is an advantage that it is not necessary to transport the object to be processed to a processing facility, and therefore, it is expected to be put into practical use. However, the inventors have found that when the in-situ method is adopted, the decomposition efficiency of the metal cyano complex by the metal cyano complex-decomposing bacteria often decreases, in particular. Then, as a result of diligent research on the influence of such conditions on the behavior of the metal cyano complex-degrading bacterium, the inventors have found that the number of indigenous microorganisms inhabiting the soil or the groundwater is artificially added. Since it is overwhelmingly large compared to the logarithm of foreign or indigenous, metal cyano complex-degrading microorganisms containing Klebsiella,
Alternatively, since there is a very strong fertility among the indigenous microorganisms, the indigenous microorganisms that do not have the metal cyano complex decomposing ability in which the nutrients and the growth environment are common grow and multiply, whereby the metal cyano complex. It was considered that the growth / proliferation of the decomposing bacterium was inhibited, and the decomposition efficiency of the metal cyano complex was significantly reduced. Therefore, as described in claim 5, when the object to be treated is soil or groundwater and one or both of them is treated in-situ, the metal cyano complex-degrading bacterium (for example, Klebsiella spp. Bacteria) Treatment of the object to be treated with an insensitive antibiotic (eg, acriflavine) to kill or reduce coexisting microorganisms that compete with the metal cyano complex-decomposing bacteria, and to grow and multiply the metal cyano complex-decomposing bacteria. By promoting the above, it becomes possible to decompose the metal cyano complex efficiently even when the in-situ method is adopted.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 illustrates an in-situ treatment facility capable of carrying out the metal cyano complex decomposition method according to the present invention. The soil 11 as the object 1 to be treated and the saturated soil 12 filled with groundwater are left in the original position, and a hollow supply pipe that vertically penetrates the object 1 to be treated is provided in the in-situ treatment facility. 2 (for example, a pipe having a large number of fine holes, a well) are provided separately. Further, when the decomposition of the metal cyano complex by an aerobic microorganism is mainly used, as an option, an air supply pipe 4 (for example, a large number of pores) penetrating the object 1 to be treated is provided similarly to the supply pipe 2. It is also possible to provide perforated pipes and wells. From the near-end portion 21 on the above-ground portion side to the supply pipe 2, an antibiotic that is insensitive to metal cyano complex-decomposing bacteria, nutrients for supporting the growth of metal cyano complex-decomposing bacteria, and the metal cyano complex-decomposing substance. It is configured such that the bacterium itself can be charged and supplied to the target processed material 1 from the tip 22 side which is the other end. The air supply pipe 4 is connected to an air pump P4 installed on the ground. When the air pump P4 is driven, fresh air is supplied from the above-ground part into the object to be treated 1 through the air supply pipe 4, thereby promoting the growth / proliferation of the metal cyano complex-decomposing bacteria.

In the case of decomposing the metal cyano complex by the metal cyano complex-decomposing bacteria native to the object to be treated 1, the near-end portion 21 is insensitive to the object to be treated 1 from the metal cyano complex-decomposing bacteria. The antibiotic treatment is performed by supplying the antibiotic. This treatment kills or reduces at least some, preferably most, of the coexisting microorganisms that do not have indigenous metal cyano complex degrading properties. During or after the antibiotic treatment, the indigenous metal cyano complex-decomposing bacterium efficiently decomposes the metal cyano complex in the object to be treated 1 in which the competing coexisting microorganisms are eliminated or reduced.

Here, the metal cyano complex-decomposing bacterium may be newly introduced from outside the object 1, and in order to promote the growth of the metal cyano complex-decomposing bacterium, oxygen or the metal cyano complex may be introduced. Nutrients that can be used by the degrading bacteria may be supplied. These can be supplied from the proximal end 21 of the supply pipe 2 in the same manner as the antibiotics.

It is also possible to select only the soil near the surface layer that is not saturated with groundwater or only groundwater as the object to be treated. In this case, the area for supplying the antibiotic or the like is adjusted by forming the tip portion 22 of the supply pipe 2 provided in the in-situ processing facility to a depth corresponding to the processing area.

Further, the method according to the present invention can be applied to the groundwater purification facility shown in FIG. In the groundwater purification facility, the intake section 32 is provided in the saturated soil 12 saturated with groundwater.
And a recovery pipe 3 (for example, a pipe and a well having a large number of fine holes) and a supply pipe 2 (for example, a pipe and a well having a large number of fine holes) provided with an injection part 22 in the soil 12. And are provided in the object to be processed 1 at a distance.

The recovery pipe is provided through a liquid storage tank 5 to which the metal cyano complex-decomposing bacteria, the metal cyano complex-decomposing bacteria insensitive antibiotics, and nutrients available to the metal cyano complex-decomposing bacteria can be added. 3 and the supply pipe 2 are connected so that gas and liquid can flow. The recovery pipe 3 and the liquid storage tank 5 are connected by a recovery passage 31, and by driving a pump P3, soil pore water (groundwater) in the soil 12 is sucked from the recovery pipe 3 into the liquid storage tank 5. It is configured to be. Further, the storage tank 5 and the supply pipe 2 are connected by a supply passage 21, and by driving the pump P2, the recovered liquid 51 (soil pore water) stored in the storage tank 5 is supplied to the supply pipe. 2 is configured to be injected. Further, the soil 12 near the supply pipe 2 is provided with an air supply pipe 4 (for example, a pipe having a large number of fine holes) to which air is injected from the pump P4, and the soil 12 is provided. On the other hand, air (air bubbles) is supplied.

The recovery pipe 3, the supply pipe 2, and the air supply pipe 4
May be provided for the soil to be purified by the same number, but any of them may be provided at a high ratio to the other, and their installation ratio, radix, soil quality, purification range, It can be determined in consideration of the purification depth and the like.

In the liquid storage tank 5, an antibiotic that is insensitive to the metal cyano complex-degrading bacterium is added to the recovery liquid 51 recovered from the recovery pipe 3, and the recovery liquid is recovered again through the supply pipe 2. By returning to the saturated soil 12, the antibiotic is spread in the groundwater. Thereby, the coexisting microorganisms sensitive to the antibiotic existing in the groundwater to be treated or the saturated soil 12 are killed or reduced, and the growth / proliferation of the metal cyano complex-degrading bacterium and the accompanying indigenous metal Promotes the decomposition of cyano complexes. Further, as an option, the metal cyano complex-decomposing bacterium, nutrients that can be used by the metal cyano-complex decomposing bacterium, and the like can be added from the supply pipe 2, whereby the growth and proliferation of the metal cyano-complex decomposing bacterium can be further performed. , And the accompanying decomposition of the indigenous metal cyano complex can be promoted.

Alternatively, the method is not limited to the in-situ method, and groundwater, which is an object to be treated, is pumped up, or soil and groundwater are mixed to form a slurry, and the slurry is introduced into a reaction tank of a known reactor. Microbial treatment can be performed by adding the above antibiotics. Alternatively, when the soil is dug up and piled up, or after the piled up, the above antibiotics may be added to carry out microbial treatment. Also in these methods, nutrients and oxygen (air) that can be used by the metal cyano complex-decomposing bacterium, or the metal cyano complex-decomposing bacterium itself can be added.

The metal cyano complex decomposing bacterium is not particularly limited, and an indigenous or foreign microorganism can be used as the object to be treated 1, and an antibiotic that is insensitive to the microorganism is used in this method. To be done. For example, as the metal cyano complex-degrading bacterium, a Klebsiella genus (Klebsiella pneumoniae AN-1 strain or the like) capable of degrading the metal cyano complex and an insensitive antibiotic to the Klebsiella bacterium can be used in combination. When acriflavine is used as the antibiotic, it can be used in combination with acriflavine-insensitive metal cyano complex degrading bacteria.

[0026]

EXAMPLES Hereinafter, a test for demonstrating the metal cyano complex decomposition method according to the present invention will be described.

[Metal Cyanocomplex Degrading Bacteria] As the Klebsiella genus having a metal cyano complex decomposing ability used in the present invention, for example, Klebsiella pneumoniae AN-1 strain isolated as follows can be used.

The sterilized ferrocyanine liquid medium placed in the flask is left in the atmosphere, and the microorganisms grown in this medium are
After inoculating on sterile ferrocyanian agar plate medium, 30 ℃
The cells were cultured in, and the formed colonies were separated. The above-mentioned composition and preparation method of the ferrocyan agar medium and the ferrocyan liquid medium are as follows.

[0029]

[Table 1] * Add pH 7.2 (±
Adjust to 0.2) and bring the total volume to 1 liter with distilled water. K ₄ [Fe (CN) ₆ ] ・ 3H ₂ O
After autoclave sterilization at 0 ° C. for 20 minutes, filter sterilized K ₄ [Fe (CN) ₆ ] .3H ₂ O solution is added.

[0030]

[Table 2] * Add pH 7.2 (±
Adjust to 0.2) and bring the total volume to 1 liter with distilled water. K ₄ [Fe (CN) ₆ ] ・ 3H ₂ O
After autoclave sterilization at 0 ° C. for 20 minutes, filter sterilized K ₄ [Fe (CN) ₆ ] .3H ₂ O solution is added.

Further, 100 ml of sterilized ferrocyanine liquid medium was dispensed into a sterilized flask, 1 platinum loop of the above-mentioned strain was inoculated, and the flask was sealed with a cotton plug so that gas could flow. Shaking culture (150 to 170 rpm) was performed at 30 ° C. for 1 week. After culturing, the content of ferrocyan (total cyanide) in the culture broth was "CN of low-quality soil.
According to the "operation method before distillation of cyanide (heating distillation method of all cyanide in soil)" described in "Method for measuring content (ring water pipe 127, item 14.2)", the culture (culture solution, bacterial cells) The whole amount was distilled, and the obtained distillate was tested by a fully automatic cyan measuring device (T-CN501 manufactured by Anatec Yanaco), and the ferrocyan (total cyan) content was measured and determined. In this way, as a result of selecting the strain decomposing ferrocyanine in the ferrocyanine liquid medium, a strain having a ferrocyanine decomposing ability was obtained, which was named AN-1 strain. The decomposition rate of ferrocyan was determined by the following formula.

Degradation rate of ferrocyanide = ferrocian content after culturing / ferrocian content after aseptic shaking × 100
(%)

After the AN-1 strain was smeared on an SCD agar plate and cultured at 30 ° C. for 1 day to confirm that it was a pure culture, the taxonomy of the AN-1 strain having the following mycological properties was obtained. The upper position is "Berjay's Manual of Systematic Bacteriology, 1st Edition" (Berg
ery's Manual of System
c Bacteriology 1st Edition
n (1984)) ". The AN
The mycological properties of the -1 strain are shown in Table 3.

[0034]

[Table 3]

As a result, the AN-1 strain was found to be Klebsiella pneum.
oniae). Here, there is no report up to now on the known Pneumonie species having the resolving power of cyanide compounds such as iron cyano complexes.
Therefore, the AN-1 strain is a new strain that is distinguished from known strains. This strain, which was determined to be Klebsiella pneumoniae AN-1 strain, was registered under the accession number FERM P-1 at the Patent Organism Depositary Center, National Institute of Advanced Industrial Science and Technology.
Deposited as No. 7792.

The composition of the SCD agar medium is shown in Table 4 below.
As shown in.

[0037]

[Table 4]

Further, the present inventors have confirmed that the AN-1 strain is
It was found that the iron cyano complex can be decomposed anaerobically in the inoculated ferrocyanine liquid medium with sodium sulfide and cysteine added and replaced with argon gas. Therefore, the AN-1 strain can decompose the metal cyano complex whether aerobic or anaerobic.

The present inventors have revealed that the AN-1 strain requires magnesium for its growth, and that addition of sodium glutamate improves the ability to decompose metal cyano complexes. Therefore, preferably, the AN-1 strain is allowed to act on the metal cyano complex in a state where these nutrients are added.

[Experimental Example] Cyan-containing soil was washed with water,
100 ml of a soil slurry containing the water used for this washing and the fine soil particles contained therein was obtained. The total cyanide content of this soil slurry was 15.3 mg-CN / L.
Met. When the form of cyan in the soil slurry was separately examined, almost 100% was present in the form of an iron cyano complex. Therefore, in the present Examples and Comparative Examples, “all cyan” substantially refers to “all iron cyano complex”. At this stage, the soil slurry contains indigenous microorganisms in the soil.
100 ml of this soil slurry was poured into an Erlenmeyer flask, and a substrate (nutrient) in a powder state was added to the Erlenmeyer flask so that the final concentration shown in Table 5 below was obtained. After this,
The pH was adjusted to 7.0.

[0041]

Table 5 L (+) - sodium glutamate monohydrate _{7.5g / L K 2 HPO 4 0.5g} / L KH 2 PO 4 0.5g / L MgSO 4 · 7H 2 O 0.5g / L yeast・ Extract 1.0 g / L D (+)-glucose 75.0 g / L urea 1.0 g / L

Further, acriflavine hydrochloride was added to the Erlenmeyer flask so that the final concentration was 0.5 g / L.
Then, the Erlenmeyer flask was shaken at 30 ° C. for 14 days to aerobically biodegrade the iron cyano complex.

The cyan concentration (substantially the iron cyano complex concentration) in the soil slurry was measured before and after the microbial treatment for 14 days, and the cyan concentration before the treatment was 15.3.
While it was 1 mg-CN / L, the cyan concentration after treatment was 10.3131 mg-CN / L. Therefore, it is considered that the iron cyano complex decomposition rate was 34% (see FIG. 3). In addition, the cyan concentration is “CN content measuring method of low-quality soil (ring water pipe 127, item 14.2)”.
According to the "pre-distillation operation method for cyanide (heating distillation method for all cyanide in soil)" described in, the total amount of the contents (soil slurry, bacterial cells) of the Erlenmeyer flask is distilled, and the obtained distillate is It was determined by using a fully-automatic cyan measuring device (T-CN501 manufactured by Anatec Yanaco) and measuring the total cyan content.

Comparative Example Under the same conditions as in the above experimental example, except that the antibiotic acriflavine hydrochloride was not added, the iron cyano complex was subjected to microbial decomposition treatment, and the iron cyano complex The concentration was measured. When the cyan complex concentration in the soil slurry was measured before and after the microbial treatment for 14 days, the cyan concentration before the treatment was 15.
While it was 2631 mg-CN / L, the cyan concentration after the treatment was 14.9831 mg-CN / L. Therefore, the decomposition rate of the iron cyano complex was 2% (see FIG. 3).

As a result of the above example, it was revealed that the decomposition rate of the iron cyano complex was significantly increased by the treatment with acriflavine. Therefore, the iron cyano complex-degrading microorganisms insensitive to the acriflavine,
When the sensitive microorganisms are killed or reduced by the action of acriflavin, the nutrients are preferentially used to grow and grow.
It is considered that they proliferated and decomposed the iron cyano complex in the soil slurry.

Here, a Klebsiella bacterium is known as the acriflavin-insensitive microorganism, and the inventors have found that Klebsiella pneumoniae belongs to Klebsiella pneumoniae.
It was confirmed that a strain having a metal cyano complex decomposing ability such as the AN-1 strain exists. Therefore, it is considered that the Klebsiella bacteria decomposed the iron cyano complex in this soil slurry.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an in-situ processing facility in which the present invention can be implemented.

FIG. 2 is a conceptual diagram showing another embodiment of the present invention.

FIG. 3 is a graph showing the correlation between the presence or absence of addition of antibiotics and the resolution of metal cyano complexes.

[Explanation of symbols]

1 Processing object 2 supply pipes 3 collection tubes 4 Air supply pipe 5 storage tanks

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C12R 1:22)

Claims (5)

[Claims] 1. A method for decomposing a metal cyano complex, which comprises treating an object to be treated containing a metal cyano complex with acriflavine and treating with a microorganism having acryflavin resistance and the ability to decompose the metal cyano complex. 2. The method for decomposing a metal cyano complex according to claim 1, wherein a nutrient usable by the microorganism is added. 3. A method for decomposing a metal cyano complex, wherein an object to be treated containing a metal cyano complex is treated with an antibiotic and treated with a Klebsiella bacterium having resistance to the antibiotic and the ability to decompose the metal cyano complex. 4. The method for decomposing a metal cyano complex according to claim 3, wherein a nutrient usable by the Klebsiella bacterium is added. 5. The object to be treated is soil or groundwater, and one or both of them are treated in situ.
5. The method for decomposing a metal cyano complex according to any one of items 1 to 4.