JP7398807B2 - Microbial adsorbent and microbial sterilization method using the same - Google Patents

Description

The present invention relates to a microorganism adsorbent that adsorbs microorganisms such as bacteria such as Escherichia coli and viruses such as avian influenza virus contained in excrement and the like, and a method of sterilizing microorganisms using the same.

Various measures have been taken against bacteria and viruses that are harmful to humans and livestock. For example, methods for disposing of livestock manure vary depending on the shape and species of livestock, but methods such as "piling up in the open" or "digging" are sources of water pollution and foul odors, and improvements are needed. . Furthermore, when treated water generated by livestock farms is discharged into public water bodies such as rivers and lakes, wastewater standards (living environment items and health items) are applied based on the Water Pollution Control Act. Although wastewater standards are set for the discharge of treated water, it goes without saying that it is desirable to reduce the number of coliform bacteria contained in treated water to zero.

Common methods for removing coliform bacteria contained in treated water include chlorine or ozone injection, ultraviolet irradiation, etc. Although chlorine injection is inexpensive, it has the problem of corroding equipment such as steel piping. be. Furthermore, ozone injection and ultraviolet irradiation have the problem of high processing costs, making it difficult for small-scale livestock farms in particular to introduce equipment.

Furthermore, avian influenza viruses may change into highly pathogenic avian influenza viruses due to mutations. It is believed that when highly pathogenic avian influenza viruses are carried in the intestinal tracts of wild birds, they drop virus-containing feces around poultry farms, which becomes a source of infection for chickens. In order to prevent the highly pathogenic avian influenza virus from entering the poultry house, it is important to spray chemicals such as lime around the poultry house, but the environmental burden and cost of using large amounts of chemicals are issues. was.

The inventors have discovered that a specific volcanic ash soil, particularly a specific Kikai Akahoya volcanic ash soil, not only has excellent adsorption performance for enterohemorrhagic E. coli and avian influenza virus, but also surprisingly has a bactericidal effect.

The present invention has been made in view of these problems, and provides a microbial adsorbent that can adsorb and sterilize microorganisms such as bacteria and viruses at low cost and with less burden on the environment, and a microbial sterilization method using the same. The purpose is to provide.

In order to solve the above problems, the microbial adsorbent of the present invention has the following features:
It is characterized by using volcanic ash soil containing 30 wt% or more of Al ₂ O ₃ .
According to this feature, it easily adsorbs moisture containing microorganisms such as bacteria and viruses, and has high adsorption and sterilization ability.

The volcanic ash soil is characterized by being Kikai Akahoya volcanic ash soil containing 3 to 8 wt% of Fe ₂ O ₃ .
According to this feature, the proportion of Al ₂ O ₃ is more than 3 times that of Fe ₂ O ₃ , and it is easy to form a complex with aluminum ions and phosphate ions, which improves the ability to adsorb and sterilize microorganisms containing phosphoric acid. Excellent in

The volcanic ash soil is characterized by containing 39 to 65 wt% of SiO ₂ , 31 to 45 wt% of Al ₂ O ₃ , 3 to 8 wt% of Fe ₂ O ₃ , and 0 to 22 wt% of other components.
According to this characteristic, there is little processing required for the natural Kikai Akahoya volcanic ash soil.

The volcanic ash soil is characterized by being calcined.
According to this feature, it is possible to eliminate various bacteria contained in the natural Kikai Akahoya volcanic ash soil.

The firing is characterized in that it is performed at a temperature of 1000°C or lower.
According to this feature, volcanic ash soil tends to have small pores, which makes it easy to adsorb microorganisms.

The volcanic ash soil is characterized by having pores with a diameter of at least 100 nm or less.
According to this feature, pores with small diameters tend to exist, and microorganisms are easily adsorbed.

The volcanic ash soil is characterized by having a specific surface area of 3.9 m ² g ^-1 or more.
According to this feature, the surface area is large and microorganisms can be easily adsorbed.

The volcanic ash soil is characterized in that it is a powder with a particle size of 1 mm or less.
According to this feature, since it is in powder form, it is easy to use it by scattering it.

The volcanic ash soil is characterized in that it is a powder with a soil particle density of 2.6 to 2.7 g/cm ³ .
According to this feature, since the soil particle density is low, it can be used while floating on water by stirring or aerating.

In order to solve the above problems, a microorganism sterilization method using a microorganism adsorbent according to the present invention is characterized in that the microorganism adsorbent is used.
According to this feature, microorganisms such as bacteria and viruses can be sterilized at low cost and with less burden on the environment.

It is a graph showing the relationship between the firing temperature and the pore size distribution of Acaca sockaca constituting the microbial adsorbent in an example of the present invention. It is a figure which shows the experimental result which investigated the adsorption ability with respect to Escherichia coli of Acacia japonica constituting the microorganism adsorbent in an example. FIG. 2 is a diagram showing the results of an experiment in which the ability of the microbial adsorbent in Example 1 of the present invention to sterilize Escherichia coli was investigated. It is a figure which shows the experimental result which investigated the adsorption ability with respect to the avian influenza virus of the microbial adsorbent in Example 2 of this invention. It is a graph showing the results of a survival test of E. coli adsorbed on a microbial adsorbent in Example 5 of the present invention. 3 is a graph showing the results of a survival test of O-157 adsorbed on a microbial adsorbent in Example 6 of the present invention.

The inventors have developed a material that adsorbs or sterilizes microorganisms such as enterohemorrhagic Escherichia coli (hereinafter sometimes simply referred to as "Escherichia coli") and other bacteria and viruses such as avian influenza virus, which are contained in livestock manure, etc. As a result, we have found that volcanic ash soil, especially natural Kikai Akahoya volcanic ash soil (hereinafter simply referred to as "Akahoya"), is excellent. Based on the research results, it was significant to focus on the components and structure, so this point will be explained first.

The mechanism of adsorption or sterilization of microorganisms by the microorganism adsorbent will be explained. Microbial adsorbents have countless pores with a diameter of 100 nm or less and have a large specific surface area, so they have excellent physical adsorption to microorganisms due to van der Waals forces and hydrogen bonds, as well as excellent water absorption. ing. Furthermore, the microbial adsorbent has a high composition ratio of Al ₂ O ₃ (aluminum oxide) and Fe ₂ O ₃ (iron oxide) and exhibits hydrophilicity, so after water absorption, it absorbs ionized Al ³⁺ (aluminum ions) and Fe ³⁺ (iron ion) exhibits high chemical bonding (chemical reactivity) with PO ₄ ^3- (phosphate ion) that constitutes the surface of microbial cell membranes (hydrophilic groups of phospholipids), and insoluble AlPO ₄ (phosphate aluminum) and FePO ₄ (iron phosphate) are produced. The chemical formula of the chemical bond between ionized Al ³⁺ and Fe ³⁺ and PO ₄ ^3- is shown in Chemical Formula 1 below.

Note that the cell membrane of microorganisms constitutes a lipid bilayer due to the self-assembly of phospholipids, and the PO ₄ ^3- that constitutes the surface of the cell membrane (hydrophilic groups of phospholipids) is combined with Al ³⁺ and Fe of the microbial adsorbent. Phospholipids are degraded by chemically bonding with ³⁺ to produce _AlPO4 and _FePO4 . In particular, E. coli is thought to die due to the decomposition of its cell membrane due to the decomposition of this phospholipid. Note that Escherichia coli floating in the treated water without being adsorbed by the microbial adsorbent is also killed by chemical bonding with Al ³⁺ and Fe ³⁺ dissolved in the treated water.

In this way, microbial adsorbents physically adsorb microorganisms through countless pores with a diameter of 100 nm or less, and ionized Al ³⁺ and Fe ³⁺ have a high chemical bond with PO ₄ ^3- , which constitutes the cell membrane of microorganisms. By producing AlPO ₄ and FePO ₄ with the above expression, microorganisms can be efficiently adsorbed or sterilized.

Embodiments for carrying out the microbial adsorbent according to the present invention will be described below based on Examples. In this example, each test result such as the component composition ratio is an average value of three or more samples.

The microbial adsorbent is made by crushing and sifting Acahoya grown in the Higashimorokken District, Miyazaki Prefecture, and then firing it under the following conditions to kill soil-borne bacteria, stabilize the constituent compounds, and maintain a certain shape and strength. ensure that
Temperature 800℃
Holding time 60 minutes (temperature increase 100℃/1 hour)
Firing equipment (ADVANTEC electric muffle furnace FUW220PA)

The component composition ratios of Acahoya before firing were as follows. The component composition ratio was analyzed in accordance with JIS K0119:2008 using an energy dispersive X-ray fluorescence spectrometer EDX-720 manufactured by Shimadzu Corporation.
51.0wt% _SiO2
39.7wt % _Al2O3
4.71wt % _Fe2O3
1.49wt% _K2O
1.40wt% CaO
0.51wt% MgO
0.53wt% _TiO2
0.66wt% Others

The component composition ratio of Acacacia after firing was as shown in Table 1 below.

Akahoya after firing has a component composition ratio of Al ₂ O ₃ of 38.3 wt % and a component composition ratio of Fe ₂ O ₃ of 3.96 wt %, and has a composition ratio of Al ₂ O ₃ and Fe ₂ O ₃ with respect to SiO _2. The ratio of

Here, the pore size distribution and specific surface area change depending on the firing temperature, which will be explained below. Note that the pore size distribution was analyzed by mercury intrusion method (JIS R1655) using AutoPore V9620 manufactured by Micromeritics.

As shown in the graph of Fig. 1, the pores of Acacacia are distributed with a diameter of 0.01 to 10 μm (100 to 10,000 nm), and at a firing temperature of 800 to 1,000°C, the pores with a diameter of 100 nm or less are 1 volume. % or more, and there is a pore distribution, but at firing temperatures of 1100°C and 1150°C, pores with a diameter of 100 nm or less are less than 1% by volume, and there is no pore distribution. That is, it was confirmed that as the firing temperature increases, the pores become clogged and the pore size distribution changes.

Further, the specific surface area was determined by the BET method (JIS Z8830) using FlowSorb3 2310 manufactured by Micromeritics.

As shown in Table 2, the specific surface area of Acahoya was 68.7 m ² g ^-1 without firing, 36.0 m ² g ^-1 at a firing temperature of 800°C, and 9.0 m 2 g -1 at a firing temperature of 900°C. 54 m ² g ^-1 , 3.9 m ² g ^-1 at a firing temperature of 1000°C, 1.35 m ² g ^-1 at a firing temperature of 1100°C, and 0.79 m ² g ^-1 at a firing temperature of 1150°C. That is, as the firing temperature increases, the specific surface area decreases due to pore blockage.

Furthermore, as shown in the photograph in Figure 2, when the suspension of E. coli was cultured in Akahoya fired at a firing temperature of 800°C, no viable bacteria were detected (see the middle row of Figure 2). . Furthermore, similar results were obtained when the E. coli suspension was filtered and the washed solution was cultured by passing the buffer solution through the Aca ascidia again (see the lower part of FIG. 2). That is, the firing of Acacacia is carried out at a firing temperature of 1000 which results in a distribution of pores with a diameter of 100 nm or less and a specific surface area of 3.9 m ² g ^-1 or more (preferably 36.0 to 69.0 m ² g ^-1 ). By carrying out the heating at a temperature of 800° C. or lower (preferably 800° C. or lower), the physical adsorption ability of microorganisms by the pores of the Acacia can be maintained. In addition, if the firing temperature is less than 100°C, soil-derived bacteria may not be sufficiently killed, so it was found that the firing temperature is preferably 100 to 1000°C, and more preferably 180 to 800°C. . Furthermore, it is preferable that there be no organic matter in the volcanic ash soil, and in this case, the firing temperature is desirably 800° C. or higher.

Next, Akadama soil produced in the Kanuma area of Tochigi Prefecture, which has been processed in the same manner as the Akahoya described above, will be explained.

The component composition ratio of Akadama clay before firing was as follows.
46.5wt% _SiO2
34.9wt % _Al2O3
13.2wt % _Fe2O3
1.37wt% _K2O
0.58wt% CaO
1.31wt% MgO
1.35wt% _TiO2
0.79wt% Others

The component composition ratio of Akadama clay after firing was as shown in Table 3 below.

Akadama soil after firing has a component composition ratio of Al ₂ O ₃ of 33.0 wt %, a component composition ratio of Fe ₂ O ₃ of 12.5 wt %, and a ratio of Al ₂ O ₃ and Fe ₂ O to SiO _2. The ratio of ₃ is high. Furthermore, compared to Acacacia, the component composition ratio of Al ₂ O ₃ is lower and the component composition ratio of Fe ₂ O ₃ is higher.

Next, clay produced in the Shintomi area of Miyazaki Prefecture that has been processed in the same manner as the Akahoya and Akadama clay described above will be described.

The component composition ratio before firing was as follows.
65.2wt% _SiO2
23.0wt % _Al2O3
5.18wt % _Fe2O3
3.71wt% _K2O
0.24wt% CaO
1.65wt% MgO
0.81wt% _TiO2
0.21wt% Others

The composition ratio of the clay after firing was as shown in Table 4 below.

The clay after firing has a component composition ratio of Al ₂ O ₃ of 22.7 wt %, a component composition ratio of Fe ₂ O ₃ of 4.76 wt %, and a ratio of Al ₂ O ₃ and Fe ₂ O ₃ to SiO _{2 .} The ratio of Moreover, the component composition ratio of Al ₂ O ₃ is lower than that of Acacacia, and the component composition ratio of Fe ₂ O ₃ is approximately the same.

Regarding whitebait produced in the Miyakonojo area of Miyazaki Prefecture, which has been processed in the same way as the Akahoya, Akadama soil, and clay mentioned above, the whitebait after firing has a general composition characteristic that is Al ₂ O ₃ compared to SiO ₂ . and a low proportion of Fe ₂ O ₃ . Moreover, the component composition ratio of Al ₂ O ₃ and Fe ₂ O ₃ is lower than that of Acacia.

Similarly, regarding Kanuma soil produced in the Kanuma area of Tochigi Prefecture, the Kanuma soil after firing has a low ratio of Al ₂ O ₃ and Fe ₂ O ₃ to SiO ₂ as a general component characteristic. Moreover, the ratios of Al ₂ O ₃ and Fe ₂ O ₃ are lower than that of Acacia.

That is, Akahoya has a higher component composition ratio of Al ₂ O ₃ that produces Al ³⁺ with a high stability constant than Akadama soil, clay, Shirasu, and Kanuma soil, and has a higher component composition ratio of Fe ₂ O ₃ than Akadama soil. Because the composition ratio is low, it is easy to form a complex with, for example, Al ³⁺ (aluminum ion) and PO ₄ ^3- (phosphate ion) in excrement, and the sequential reaction between this complex and PO ₄ ^3- that constitutes the cell membrane of microorganisms occurs. occurs, and microorganisms can be adsorbed more efficiently.

In this way, the microbial adsorbent is composed of Aka ascidia, a natural material that exists in inexhaustible quantities in relatively shallow underground areas in southern Kyushu, and has a high ability to adsorb microorganisms such as bacteria and viruses. It can be done inexpensively and with less burden on the environment. Incidentally, the Acahoya used as the microbial adsorbent is not limited to those produced in the Higashimorokken District, Miyazaki Prefecture, as long as it is produced in southern Kyushu.

Incidentally, the volcanic ash soil of Acahoya or the like in each of the following Examples uses the one having the above-mentioned components.

The microbial adsorbent according to Example 1 will be explained. The microbial adsorbent of Example 1 was constructed by filling a cylindrical column with a diameter of 15 mm with 10 g of Acacia japonica, which was pulverized and sterilized with dry heat under the following conditions, and then adjusted to a particle size of 0.5 mm or less. .
Temperature 180℃
Time: 40 minutes Dry heat sterilizer (ADVANTEC STA620DA)

After passing 10 ml of Escherichia coli (10 ⁵ cfu/ml) through the microbial adsorbent, 10 mg of Acacacia in the column was stored at 4°C, and the viability of the adsorbed Escherichia coli was confirmed by a culture method, as shown in the photograph in Figure 3. As shown, the E. coli that was adsorbed to the Acacia died over time, and no viable bacteria were detected after 6 days (see the left Petri dish in Figure 3). As a control experiment, when the same column was filled with 10 g of whitebait produced in the Miyakonojo area of Miyazaki Prefecture and a similar experiment was conducted, viable bacteria were detected until 17 days later (see the petri dish on the right in Figure 3). In other words, the microbial adsorbent made from Acacia as a material has the ability to adsorb and sterilize Escherichia coli.

In this example, an example was explained in which Acacia sterilized by dry heat at 180°C for 40 minutes, but similar results were obtained with Acacacia sintered at a firing temperature of 800°C.

The microbial adsorbent according to Example 2 will be explained. The microbial adsorbent of Example 2 was constructed by placing 0.2 g of crushed and dry-heat sterilized Acaca japonica into a 0.6 ml column (microtube).

Inoculate 0.4 ml of avian influenza virus (H3N2 subtype) (HA value 16 times, see second row from the top of Figure 4) onto the microbial adsorbent, and dilute the liquid that has passed through the Aka ascidian 2 to 256 times. When the hemagglutination titer (HA titer) was measured, as shown in the photograph in Figure 4, the avian influenza virus was adsorbed to the red ascidian and did not agglutinate with blood cells (HA titer negative, two rows from the bottom of Figure 4). (see item). As a control experiment, when a similar experiment was carried out using 0.2 g of whitebait produced in the Miyakonojo area of Miyazaki Prefecture in a 0.6ml column, the avian influenza virus was hardly adsorbed to the whitebait and aggregated with blood cells ( HA value 8 times, see bottom row of Figure 4). In other words, the microbial adsorbent made from Acacia japonica has the ability to adsorb avian influenza virus.

The microbial adsorbent according to Example 3 will be explained. The microorganism adsorbent of Example 3 is natural or calcined Acacacia, which is put into a large container together with the object to be treated such as livestock manure, and then stirred to remove microorganisms such as Escherichia coli contained in the object to be treated. adsorbs or sterilizes while promoting contact with Note that the sludge (microbial adsorbent after use) generated in these treatments can be returned to the earth, so the treatment cost is low and sludge treatment equipment is not required.

The microbial adsorbent according to Example 4 will be explained. The microbial adsorbent of Example 4 is a natural or calcined Acaca sacrifice that has been processed into a powder with a particle size of 0.5 mm or less, making it easy to disperse. The powdered microbial adsorbent can adsorb or sterilize microorganisms present around the livestock barn, for example, by being sprayed around the livestock barn, thereby preventing microorganisms from entering the livestock barn. In addition, by using the natural material Acacia as a microbial adsorbent, the cost is low even when spraying in large quantities, and the environmental impact is low.

For these reasons, the particle size is 1 mm or less, preferably 0.5 mm or less, and more preferably 0.1 mm or less.

Furthermore, the microorganism adsorbent material may be agitated or aerated so that it can be used in a suspended state in water. In addition, for example, by filling a tray installed at the entrance of a livestock barn with water, spraying the microbial adsorbent on the water surface, and leaving it floating on the water surface, the microbial adsorbent can be firmly attached to shoes, livestock legs, etc. It is possible to reliably adsorb or sterilize microorganisms present on shoes, livestock legs, etc., and prevent microorganisms from entering the livestock barn.

For these reasons, the soil particle density is preferably 2.6 to 2.7 g/cm ³ , and it is further preferable that the density is as low as possible. Note that the soil particle density was determined according to JIS A1202:2009.

Example 5 describes a survival test for E. coli. The microbial adsorbent of Example 5 was pulverized and dry heat sterilized under the following conditions, and then 10 g each of Akahoya, Akadama soil, Kanuma soil, and Shirasu adjusted to a particle size of 0.5 mm or less was placed in a cylindrical column with a diameter of 15 mm. It is constructed by filling each.
Temperature 180℃
Time: 40 minutes Dry heat sterilizer (ADVANTEC STA620DA)

After passing a fixed amount of E. coli through the microbial adsorbent, 10 mg each of Akahoya, Akadama soil, Kanuma soil, and Shirasu in the column were stored at 4°C, and the viability of the adsorbed E. coli was confirmed by a culture method. As shown in the graph, it was confirmed that the number of E. coli bacteria adsorbed to Akahoya, Akadama soil, Kanuma soil, and Shirasu decreased over time. In this way, microbial adsorbents made from Acacia, Akadama soil, Kanuma soil, and whitebait have the ability to adsorb and sterilize Escherichia coli.

Here, since it can be said that a significant bactericidal effect is achieved when the number of bacteria is reduced to 1/100, that is, 99% of bacteria are killed, this value was used as the evaluation standard. The number of days for the number of bacteria to decrease to less than 1/100th, that is, the number of days for E. coli to die, is 3 days for E. coli adsorbed to Akahoya and Akadama soil, 9 days for E. coli adsorbed to Kanuma soil, and 9 days for E. coli adsorbed to Shirasu. After 17 days, the bactericidal effects of each were confirmed. In this way, it was confirmed that the microbial adsorbent made from Akahoya and Akadama soil can provide a bactericidal effect in a short period of time. Furthermore, the number of E. coli bacteria adsorbed to Akahoya, Akadama soil, and Kanuma soil decreased to approximately 1 log cfu/g after 17 days, confirming that almost all bacteria were sterilized over a long period of time. It was done.

Example 6 describes a survival test for enterohemorrhagic E. coli O-157. Note that the microbial adsorbent manufactured in the same manner as in Example 5 was used.

After passing a fixed amount of enterohemorrhagic Escherichia coli O-157 (hereinafter simply referred to as "O-157") through the microbial adsorbent, 10 mg each of Akahoya, Akadama soil, Kanuma soil, and Shirasu in the column were added to 4 When the viability of the adsorbed O-157 was confirmed by a culture method after storage at ℃, as shown in the graph in Figure 6, the O-157 adsorbed to Akahoya, Akadama soil, and Kanuma soil deteriorated over time. It was confirmed that the number of bacteria was decreasing. In this way, microbial adsorbents made of Akahoya, Akadama soil, and Kanuma soil have the ability to adsorb and sterilize O-157.

Here, since it can be said that a significant bactericidal effect is achieved when the number of bacteria is reduced to 1/100, that is, 99% of bacteria are killed, this value was used as the evaluation standard. The number of days for the number of bacteria to decrease to less than 1/100th, that is, the number of days for O-157 to die, is 7 days for O-157 adsorbed on Akahoya and Akadama soil, and 14 days or more for O-157 adsorbed on Kanuma soil. After that, the bactericidal effect of each was confirmed. In this way, it was confirmed that the microbial adsorbent made from Akahoya and Akadama soil can provide a bactericidal effect in a short period of time. Furthermore, the number of O-157 bacteria adsorbed on Akahoya and Akadama clay decreased to approximately 1 log cfu/g after one month, confirming that almost all bacteria were sterilized over a long period of time. Ta.

From these Examples 5 and 6, as shown in Table 5, the microbial adsorbent made from Akahoya and Akadama soil has a significant effect on E. coli and O-157 compared to the microbial adsorbent made from Kanuma soil and whitebait. It has excellent sterilizing ability. In addition, "○" in Table 5 indicates that there is a significant bactericidal ability, "△" indicates that the bactericidal ability is present although it takes a long period of time, and "x" indicates that the bactericidal ability was insufficient. It shows.

Furthermore, referring to FIG. 5, Akahoya is superior to Akadama soil in terms of short-term (within 3 days) bactericidal ability against E. coli, that is, the rate of decrease in the number of bacteria from day 0 to 3 days later. Similarly, referring to FIG. 6, Akadama soil is superior to Akahoya in terms of short-term (within 7 days) bactericidal ability against O-157, that is, the rate of decrease in the number of bacteria from day 0 to 7 days later.

Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and any changes or additions that do not depart from the gist of the present invention are included in the present invention. It will be done.

For example, in Examples 1 to 4, examples were explained in which the microbial adsorbent was natural or processed such as _calcination , but the _invention is not limited to this. For example, natural Akadama soil or fired Akadama soil may be used as long as it is a volcanic ash soil, such as Kanuma soil, clay, whitebait, etc., which is processed to contain 30 wt% or more of Al ₂ O ₃ . It may be a processed one.

In addition, the microbial adsorbent has an adsorption effect on microorganisms other than E. coli (e.g., Staphylococcus aureus, Salmonella spp., Campylobacter, Bacillus subtilis spores, Bacillus anthrax spores, etc.) and viruses other than avian influenza virus. play.

Further, the microbial adsorbent is not limited to firing, and may be sterilized by, for example, ultraviolet rays.

Industrial applications

1. Use as an adsorbent in purification systems for livestock breeding environments.
2. Use in air purification systems, for example as an adsorbent to adsorb microorganisms in the air.
3. Water purification systems, such as removal of nutrient salts (phosphorus) in closed water bodies (lakes) and use as an adsorbent for microorganisms such as Escherichia coli or coliform bacteria.
4. Use as an adsorbent for bacteria and viruses such as anthrax spores in bioterrorism countermeasure systems.
5. Use as feed containing pathogen-adsorbing substances.

Claims (8)

Using volcanic ash soil containing 30 wt% or more of Al ₂ O ₃ ,
A microbial adsorbent characterized in that the volcanic ash soil is Kikai Akahoya volcanic ash soil containing 3 to 8 wt% of Fe ₂ O ₃ . Using volcanic ash soil containing 30 wt% or more of Al ₂ O ₃ ,
A microbial adsorbent characterized in that the volcanic ash soil contains 39 to 65 wt% of SiO ₂ , 31 to 45 wt% of Al ₂ O ₃ , 3 to 8 wt % of Fe ₂ O ₃ , and 0 to 22 wt % of others. The microbial adsorbent according to claim 1 or 2 , wherein the volcanic ash soil is calcined. The microorganism adsorbent according to any one of claims 1 to 3 , wherein the volcanic ash soil has pores with a diameter of at least 100 nm or less. The microbial adsorbent according to any one of claims 1 to 4 , wherein the volcanic ash soil has a specific surface area of 3.9 m ² g ^-1 or more. The microorganism adsorbent according to any one of claims 1 to 5 , wherein the volcanic ash soil is a powder with a particle size of 1 mm or less. The microbial adsorbent according to any one of claims 1 to 6 , wherein the volcanic ash soil is a powder with a soil particle density of 2.6 to 2.7 g/cm ³ . A method for sterilizing microorganisms using the microorganism adsorbent according to any one of claims 1 to 7 .

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