JP2019180339A - Method and apparatus for producing hydrogen - Google Patents

Abstract

To provide methods and an apparatus for efficiently producing hydrogen using a particular microorganism and for detoxifying acetic acid that is a by-product.SOLUTION: Provided is a method for producing hydrogen comprising culturing microorganisms of Thermococcus using a culture solution to which a carbon source is added to make the microorganisms of Thermococcus produce hydrogen; and detoxifying acetic acid produced during hydrogen production using at least one selected from waste, shellfish and bone that contain calcium as a component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method and apparatus for producing hydrogen using microorganisms.

  In recent years, biomass-derived fuel production has been studied as an alternative to petroleum-derived fuels due to concerns such as depletion of fossil fuels and global warming. As biomass currently being studied, food waste, wood, paper, and the like are known as those derived from waste. Hydrogen gas is also attracting attention as clean energy that can be generated from such waste biomass.

  At present, typical methods for industrial production of hydrogen are steam reforming of naphtha, petroleum off-gas, butane, LPG, natural gas (mainly methane) and the like. In addition, a method of partially oxidizing heavy oil is also employed. In any case, the actual production of hydrogen depends on fossil fuels. For this reason, there is a concern about the future depletion of fossil fuels before Oita, and there is a situation that a hydrogen production method that does not depend on fossil fuels is desired.

  In response to such problems, a method for efficiently producing hydrogen, which is clean energy, from this waste biomass by using hyperthermophilic bacteria has been reported.

  As an example of such a hydrogen-producing hyperthermophilic bacterium, a technique for biologically producing hydrogen by culturing a microorganism belonging to the genus Thermococcus, in particular, Thermococcus kodakaraensis, has been proposed (for example, see Patent Document 1). ). Patent Document 1 describes a method for producing hydrogen in which a microorganism is produced by culturing a microorganism of the genus Thermococcus.

  Similarly, by using a microorganism of the genus Thermococcus and culturing together with a support, a biofilm is formed using the support as a nucleus, and the microbial cells are cultured in the state of the biofilm to thereby generate hydrogen. A method for producing hydrogen to be produced has also been reported (Patent Document 2).

  On the other hand, microorganisms of the genus Thermococcus are known to produce hydrogen in the process of producing pyruvic acid from a carbon source such as starch, but at the same time, it is also known to produce acetic acid (non-patent literature). 1). Since acetic acid is an inhibitor of the growth of microorganisms belonging to the genus Thermococcus, hydrogen production stops after a certain amount of hydrogen is produced. Therefore, when hydrogen is continuously produced, it is necessary to lower the acetic acid concentration by partially replacing the medium, removing or decomposing acetic acid after a predetermined amount of acetic acid is produced.

Japanese Patent No. 3771475 Japanese Patent No. 5058536

Journal of Environmental Biotechnology, Vol. 9, no. 2, 65-68 (2009), Fig. 4 etc.

  Known methods for removing acetic acid include (1) a method of removing it by adsorption on activated carbon, or (2) a method of generating and decomposing OH radicals. However, in the removal method (1) above, it is necessary to frequently replace or regenerate the activated carbon on which acetic acid has been adsorbed with a new one in order to perform continuous culture. Replacement requires a running cost, and even if it is played back, a playback device or the like is required, resulting in an initial cost. Moreover, since water-soluble organic substances other than acetic acid are present in the culture medium, there is a concern that the frequency of replacement and regeneration of activated carbon increases, and that more costs are required.

  As the decomposition method (2), a method using a photocatalyst and a method for generating plasma in water are known, both of which require an apparatus for generating OH radicals. Electric power is required to continue operating the device. Furthermore, although a chemical method for adding hydrogen peroxide is also known, running costs are incurred because chemicals must be constantly added.

  On the other hand, disposal of oysters and other shells of shells after use as food, or animal bones has become a problem. Some of these are used as soil conditioners and the like, but most of them become waste. Therefore, there is also a need for such a waste recycling method.

  The present invention has been made in view of the above circumstances, and in a method and apparatus for efficiently producing hydrogen using a specific microorganism, the generation of acetic acid, which is a harmful substance, is suppressed without increasing the cost, and the efficiency The objective is to produce hydrogen continuously. And the present inventors discovered that the said subject can be solved with the following structure.

  That is, in the method for producing hydrogen according to one embodiment of the present invention, the microorganism of the genus Thermococcus is produced by culturing the microorganism of the genus Thermococcus using a culture solution to which a carbon source is added. And detoxifying acetic acid produced during production using at least one selected from waste, shellfish and bone containing calcium as a component.

  Further, in the above production method, it is preferable to produce a hydrogen by culturing with a support during cultivation.

  Further, the support is natural sponge, synthetic sponge, activated carbon, ceramic, ion exchange resin, zeolite, foam stone, molten slag, cellulose acetate fiber, and glass beads, carbon, silica gel, sand, alumina, molecular sieve, and One or more selected from the group consisting of titanium oxides are preferred.

  Or it is also preferable that the said support body is at least 1 sort (s) selected from the waste, shellfish, and bone which contain the said calcium as a component.

  Furthermore, in the production method, the microorganism of the genus Thermococcus is preferably Thermococcus kodakarensis.

  Further, it is preferable that Thermococcus kodakarensis is Thermococcus kodakarensis KOD1 (depositing organization: National Institute of Advanced Industrial Science and Technology, Patent Biological Depositary, Accession Number: FERM P-15007).

  In addition, the hydrogen production apparatus according to another aspect of the present invention includes a culture tank for culturing a microorganism of the genus Thermococcus using a culture solution to which a carbon source is added, acetic acid generated during hydrogen production, and calcium as a component. It includes at least a detoxification tank that is detoxified using at least one selected from waste, shellfish, and bone.

  Furthermore, in the manufacturing apparatus, it is preferable that the culture tank and the detoxification tank are integrated.

  According to the present invention, hydrogen, which is a clean energy, can be efficiently generated using a microorganism of the genus Thermococcus without depending on fossil as a raw material. Since acetic acid produced by a Thermococcus genus microorganism in the process of generating hydrogen can be detoxified using waste or the like, it is possible to produce hydrogen continuously and efficiently without cost. In addition, since the hydrogen production method of the present invention uses shells, bones and the like that are usually discarded, not only does the running cost occur, but also the waste is effectively used.

FIG. 1 is a schematic diagram illustrating an example of a hydrogen production apparatus according to the present embodiment. FIG. 2 is a schematic view of the hydrogen production apparatus used in the examples.

  As a result of diligent efforts, the present inventors have found a method for efficiently detoxifying acetic acid produced by a Thermococcus genus microorganism in the process of generating hydrogen, and further researched to achieve the present invention. did.

  That is, the method for producing hydrogen of the present invention causes a microorganism of the genus Thermococcus to produce hydrogen by culturing the microorganism of the genus Thermococcus using a culture solution to which a carbon source is added, and is produced at the time of hydrogen production. And detoxifying acetic acid using at least one selected from waste, shellfish and bone containing calcium as a component.

  Hereinafter, preferred embodiments of the present invention will be specifically described, but the present invention is not limited thereto.

  In the method for producing hydrogen according to the present embodiment, a microorganism of the genus Thermococcus is cultured using a culture solution to which a carbon source is added, thereby producing hydrogen in the cells.

  In the present embodiment, Thermococcus kodakarensis is preferably used as the microorganism of the genus Thermococcus. Furthermore, it is more preferable to use Thermococcus kodakarensis KOD1, which is a bacterium belonging to Thermococcus kodakarensis. This strain KOD1 is deposited as a deposit number: FERM P-15007 at the National Institute of Advanced Industrial Science and Technology (AIST), which is a public organization, and can be easily obtained by those skilled in the art. The deposit is Pyrococcus sp. Although it is registered with KOD1 or Pyrococcus kodakarensis KOD1, it is exactly Thermococcus kodakarensis KOD1 (Journal of Bacteriology, Vol. 182, No. 22, Nov. 2000, p. 6424-6433, etc.).

  As the culture solution of the present embodiment, those having various medium compositions are used. Typical examples include a basic medium containing salt, a medium (MA medium) added with artificial sea salt, and the like. Furthermore, yeast extract or tryptone may be added to the culture solution.

  And in this embodiment, a carbon source is added to this culture solution as a substrate. The carbon source that can be used is not particularly limited, and examples thereof include starch-based polysaccharides, cellulose-based polysaccharides, and various types of biomass. These carbon sources are used alone or in combination.

  As starch-based polysaccharides, raw starch such as corn starch, potato starch, sweet potato starch, wheat starch, cassava starch, sago starch, tapioca starch, rice starch, bean starch, waste starch, warabi starch, lotus starch, diamond starch; Physically modified starch such as α-starch, fractionated amylose, wet heat-treated starch; hydrolyzed dextrin, enzymatically modified dextrin, enzyme modified starch such as amylose; chemically degraded starch; chemically modified starch and the like.

  Examples of cellulosic polysaccharides include wood and paper. For example, waste materials from sawmills and housing demolition materials, wood waste (chip waste wood), wood pellets, dead leaves / dead branches, paper waste It is possible to use a wide variety of woody and paper waste organic materials such as paper materials. Moreover, what contains many insoluble dietary fibers, such as a potato peel, can also be used as a cellulosic polysaccharide.

  The concentration of the carbon source added to the culture solution is suitably 0.01 to 5% (w / w) in the case of starch-based polysaccharides and cellulose-based polysaccharides. At such a concentration, it is considered that the object of the present invention can be achieved to the maximum extent. A preferable range of the concentration is 0.1 to 3% (w / w), and a more preferable range is 0.2 to 2% (w / w).

  Furthermore, an amino acid source or the like generally used for culturing bacterial cells may be added to the culture solution.

  In the actual culturing operation, it is desirable to inoculate a culture solution to which a carbon source as described above is added separately from a pre-cultured microorganism of the genus Thermococcus, and then to start the main culture.

  The culture temperature is preferably set to a growth temperature of a microorganism of the genus Thermococcus that is a hyperthermophilic bacterium, that is, a temperature of 60 to 105 ° C. More preferably, it is desirable to set the temperature at 60 to 100 ° C, more preferably 70 to 95 ° C, and most preferably 80 to 90 ° C. When the temperature is lower than 60 ° C., the amount of hydrogen generated is insufficient, while when the temperature exceeds 105 ° C., the amount of generated hydrogen tends to decrease. The optimum growth temperature of Thermococcus kodakarensis KOD1 preferably used in the present embodiment is around 85 ° C., which is extremely high for general microorganisms, and it is not preferable to deviate from this temperature extremely.

  Furthermore, in culturing, it is preferable to perform the culturing in an anaerobic atmosphere without light irradiation and in the absence of elemental sulfur (elemental sulfur). Thereby, hydrogen can be produced more efficiently using a microorganism of the genus Thermococcus. In that case, even if a trace amount of oxygen is contained in the atmosphere, a trace amount of light enters during the culture, or a trace amount of elemental sulfur is added to the culture solution, they are merely nominal. However, it should be noted that it does not depart from the technical scope of the present invention if it does not detract from the spirit of the present invention.

  In general, microorganisms often die or cannot grow at a high temperature of 60 ° C. or more except for special bacteria isolated from a hot spring hot spring outlet. Therefore, being able to grow at a high temperature of 60 to 105 ° C. like the microorganism of the present embodiment can avoid contamination due to the propagation of other bacteria during culture, and can easily propagate only the desired thermophilic bacteria. There is an advantage that you can.

  In addition, according to the present embodiment, light irradiation which is indispensable when hydrogen is generated using a photosynthetic bacterium is not required, so that facilities necessary for light irradiation can be reduced and simplified. Furthermore, there is an advantage that the risk of the hydrogen generation efficiency being significantly lowered due to light being absorbed or blocked by the organic matter generated and adhered to the light irradiation portion can be avoided.

  Further, as one preferred embodiment, particularly when the culture solution is agitated in order to improve the temperature distribution in the culture tank, in order to prevent the microorganisms from being destroyed or stressed by the shearing force generated by the agitation means, It is preferable to stir as slowly as possible and to cultivate with a support when culturing the microorganism. Thereby, a biofilm is formed using the support as a nucleus, and the cells of the microorganism can be cultured at a higher density in the state of the biofilm.

  In the present embodiment, the support is one that adsorbs bacterial cells. This support is preferably porous. The distribution of pore diameters in the porous support is not constant, and most of them have a large statistical dispersion. On the other hand, the cell size is about 1 μm when the KOD1 strain matures, for example. Therefore, the pore diameter of the porous support is preferably 1 μm or more. This makes it easier for the bacterial cells to enter the porous support and be adsorbed.

  Further, the pore diameter of the porous support is more preferably 20 μm or more. Thereby, the proliferated microbial cells can be held inside the porous support. As a result, the cell density can be increased. The pore diameter of the porous support is more preferably 100 μm or more. Thereby, while supplying a culture solution efficiently to the microbial cells adsorbed inside the porous support, the consumed culture solution (waste solution) can be efficiently discharged to the outside of the porous support. it can. As a result, it is possible to promote the growth of microbial cells in the porous support body. In addition, since a biofilm can be formed inside the porous support, the cells in the porous support can be more immobilized.

  In addition, it is preferable that the hole diameter of the hole of a porous support body is 300 micrometers or less. Thereby, the surface area of a porous support body can be made sufficiently wide, and the adsorption amount of a microbial cell can be increased.

  The shape of the support is not particularly limited, but the volume is preferably small. When the volume is small, when a predetermined amount of the support is filled in the culture tank, the surface area of the entire support increases with respect to the volume of the culture tank, making it easier to immobilize the cells and forming a biofilm with the support as the core. can do.

  The support is preferably subjected to adsorbent coating or surface treatment. Thereby, the adsorption amount of a microbial cell can further be increased. As this adsorbent and surface treatment, those that adsorb microorganisms and are stable at the culture temperature of the cells are preferably used. For example, a cellulose carrier (trade name: Cellsnow ™) manufactured by Kirin Beer / Sake Engineering Co., Ltd. may be mentioned.

  The material of the support only needs to have a function of adsorbing bacterial cells, for example, natural sponge, synthetic sponge, activated carbon, ceramic, ion exchange resin, zeolite, foam stone, molten slag, cellulose acetate fiber, glass beads, It is preferably one or more selected from the group consisting of carbon, silica gel, sand, alumina, molecular sieve, and titanium oxide. These supports can be suitably used because they are easily available and easy to process.

  Thermococcus microorganisms produce hydrogen during the growth process and also produce acetic acid. Since acetic acid becomes a factor that inhibits the growth of the microorganism of this embodiment, hydrogen production stops after a certain amount of hydrogen is produced. Therefore, in this embodiment, acetic acid produced during hydrogen production is rendered harmless using at least one selected from waste, shellfish, and bone containing calcium as a component.

  In the detoxification step of this embodiment, acetic acid is reacted with calcium contained in the shellfish and bones to change to harmless calcium acetate. By this detoxification step, continuous cultivation of microorganisms belonging to the genus Thermococcus can be realized without using special equipment or chemicals, and hydrogen can be produced efficiently and continuously.

  The waste, shellfish and bone containing calcium as a component are preferably waste, shellfish and bone containing a large amount of calcium. In the present embodiment, “comprising calcium as a component” means that calcium is contained in an amount sufficient to change the produced acetic acid to calcium acetate.

  Specific wastes, shellfish and bones include, for example, oyster shells, shells of other shellfish, bones of animals (for example, edible fish), calcium-containing sludge and the like. Such calcium-containing wastes, shellfish and bones often come out as wastes from ordinary households, restaurants, etc., and are usually discarded without being reused. In the present embodiment, by reusing these wastes, it is possible not only to spend no cost on acetic acid detoxification, but also to contribute to the effective use of wastes.

The microorganism (KOD1) produces about 4 moles of hydrogen per mole of starch. At this time, it is known that about 2 mol of acetic acid is also produced. Therefore, the amount of waste, shellfish and bone necessary for detoxifying acetic acid is 1 mol (about 100 g) calcium carbonate and 2 mol (about 120 g) acetic acid, 1 mol (about 160 g) calcium acetate and water (H By using the chemical formula that 1 mol of ₂ O) and 1 mol of carbon dioxide (CO ₂ ) are generated, the required amount of calcium can be determined, and therefore, depending on the proportion of calcium contained in waste, shellfish and bones It can be adjusted appropriately.

  Further, detoxification is preferably performed at a high temperature. Specifically, it is desirable to carry out at about 60 ° C. to 105 ° C. (the growth temperature of the microorganism). In particular, since the microorganism used in the present embodiment is a hyperthermophilic bacterium, it is considered preferable to perform detoxification at the growth temperature of the microorganism.

  The step of detoxifying acetic acid can be performed after culturing the microorganism, but may be performed simultaneously with the culturing. In that case, at least one selected from wastes containing calcium as a component, shellfish, and bone can be used as the support as described above. In many cases, wastes containing calcium as a component, shellfish, bones, etc. (wastes such as oyster shells and animal bones) are porous, and thus can also serve as the support. .

<Hydrogen production equipment>
As shown in FIG. 1, an apparatus for producing hydrogen for carrying out the above method
A culture tank (1) for culturing a microorganism of the genus Thermococcus using a culture solution to which a carbon source (6) is added;
A detoxification tank (2) for detoxifying acetic acid produced during hydrogen production using at least one (4) selected from wastes, shellfish and bones containing calcium as a component. is there.

  According to the apparatus of this embodiment, the medium containing acetic acid produced in the culture tank (1) is sent to the detoxification tank (2), detoxified, and returned to the culture tank (1), whereby the microorganisms are removed. Continuous culture allows hydrogen to be produced efficiently and continuously.

  Furthermore, the hydrogen production apparatus of the present embodiment is suitably provided with gas deriving means (5) for deriving hydrogen-rich gas generated in the culture tank (1).

  Moreover, when sending a culture solution from a culture tank (1) to a detoxification tank (2), the said culture tank (1) so that many said microorganisms in a culture tank (1) may not flow out to a detoxification tank (2). It is preferable that a support (3) is installed inside.

  The connecting means between the culture tank (1) and the detoxification tank (2) may be provided with a pump or the like, whereby clean (inhibiting the growth of microorganisms) from the detoxification tank (2). The medium (with reduced acetic acid concentration) can be sent to the culture tank (1) in a certain amount. However, when the culture solution is sent by the pump or the like, it is preferable to consider so that the microorganisms flowing out from the culture tank (1) are not damaged by the shearing force when passing through the pump.

  Although the culture tank (1) and the detoxification tank (2) are shown separately in FIG. 1, these may be one integrated tank. In that case, the waste, shellfish and bone (4) can also serve as the support (3).

  As the waste, shellfish, bone (4) and support (3), the same materials as those described in the above-mentioned “Method for producing hydrogen” can be used.

  In this embodiment, the material of the tank (culture tank and detoxification tank) is required to withstand a temperature of around 100 ° C. And since a high concentration salt is used for a culture medium and hydrogen sulfide may generate | occur | produce at the time of culture | cultivation, a thing with high corrosion resistance is used. For example, acid resistant metals such as aluminum, various stainless steels, and hastelloy are used. In particular, in the case of stainless steel, austenitic stainless steel is desirable, and SUS316L, SUS304, and the like are most desirable. However, these metals are not perfect with respect to corrosion resistance. In consideration of corrosion resistance, the resin may be polyethylene, polypropylene or the like, but a fluororesin having high heat resistance is desirable, and in particular, polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene. -Perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) and the like are most preferable. Here, considering the characteristics of anaerobic bacteria, it is desirable not to contact oxygen as much as possible during culture. However, these resins have the disadvantage of high oxygen permeability compared to metals, and when the resin is used, the thickness of the tank is increased in order to maintain a sufficient shape in strength. There is a disadvantage that the cost is high. In consideration of corrosion resistance and oxygen barrier properties, various glasses may be used, but there is a drawback that they are easily broken. Therefore, from the viewpoint that corrosion resistance is high, oxygen permeability is low, and strength is high, it is optimal that a metal such as SUS316L or SUS304 is coated or lined with a fluorine resin as described above. it can.

  The culture tank (1) and the detoxification tank (2) may be a single tank or a plurality of tanks. The shape of the tank is not particularly limited, but is preferably a cylindrical shape.

  Further, a simple pipe is sufficient for the gas outlet means (5). It is desirable that the material is basically the same as that suitable for the culture tank. In addition, various rubbers may be used because of their high degree of freedom. Particularly, ethylene / propylene rubber and fluorine rubber (such as hexafluoropropylene-vinylidene fluoride copolymer) having low gas permeability are resistant to acid. It is an example of a preferable material in terms of heat resistance.

  Furthermore, since the microorganism to be used is a hyperthermophilic bacterium, the culture tank (1) may be provided with a heating means (not shown) for adjusting the culture temperature. Various heating mechanisms such as a jacket type and an electric heating type can be adopted as the heating means. Especially for the heating method, the inside of the culture tank may be stirred by a stirrer, so it is equipped with a magnetic stirrer equipped with a heating part (heater) at the bottom, and the tank body part is used to heat up efficiently. It is desirable to equip a mantle heater for heat retention or heating so as to heat.

  As described in the section of “Method for producing hydrogen”, Thermococcus kodakarensis is used as the above-mentioned microorganism of the genus Thermococcus, and the culture is carried out in an anaerobic atmosphere without irradiation with light and elemental sulfur (single element It is preferable to carry out in the absence of sulfur.

  In that case, the apparatus may be provided with an inert gas supply means (not shown) for culturing in an anaerobic atmosphere.

  As the inert gas supply means, means for supplying an inert gas such as nitrogen gas can be employed. It is desirable that the purity of the inert gas be as high as possible. Examples of the inert gas include semiconductor material nitrogen (purity 99.9999% or more, oxygen content less than 0.1 ppm (v / v), manufactured by Taiyo Toyo Oxygen Co., Ltd.) High purity nitrogen (US grade nitrogen, purity 99.99995% or more, oxygen content less than 0.1 ppm (v / v), manufactured by Taiyo Toyo Oxygen Co., Ltd.) and the like are preferably used.

  The supply of inert gas is not always necessary during culture, but is necessary to discharge the dissolved oxygen in the culture solution out of the system in advance before culturing. In addition, the hydrogen generated during the culture is quickly removed from the culture solution. It is also desirable to supply it for the purpose of moving it out of the system.

  Moreover, in order to culture without irradiating light, it is preferable that the hydrogen production apparatus of this embodiment is provided with a light shielding means (not shown).

  In addition, the mechanical stirring system which agitates with a mechanical stirring means using a closed culture tank (1) omits the inert gas supply means for maintaining anaerobic and gas stirring efficiently and reliably. It is also possible to adopt a self-gas stirring system in which a part of the gas generated from the culture tank (1) is returned to the culture solution in the culture tank (1) and stirred. In addition, various means for concentrating and separating hydrogen gas, various control means, various abatement means, and the like can be attached as necessary.

  Hydrogen obtained by the method or apparatus of this embodiment is used for hydrogenation reaction in the fat and oil industry, welding with oxygen / hydrogen flame, metal reduction treatment, glass melting, reduction treatment in the semiconductor industry, rocket fuel (liquid hydrogen). It can be used for new applications such as conventional fuel cell fuels and fuel cell fuels for automobiles.

  As described above, the present specification discloses various modes of technology, of which the main technologies are summarized below.

  The method for producing hydrogen according to one aspect of the present invention includes causing a microorganism of the genus Thermococcus to produce hydrogen by culturing a microorganism of the genus Thermococcus using a culture solution to which a carbon source is added, and at the time of hydrogen production. Detoxifying the produced acetic acid using at least one selected from wastes, shellfish and bones containing calcium as a component.

  With such a configuration, hydrogen that is clean energy can be efficiently generated without depending on fossil as a raw material. In addition, since acetic acid produced in the process of generation of hydrogen by Thermococcus microorganisms can be rendered harmless using shells, bones, or the like, hydrogen can be efficiently and continuously produced without cost. Furthermore, the hydrogen production method of the present invention uses shells and bones that are normally discarded, so that not only running cost does not occur, but also waste is effectively used.

  Further, in the above production method, it is preferable to produce a hydrogen by culturing with a support during cultivation. Thereby, since the said microorganisms can be cultured with higher density, it is thought that the efficiency of hydrogen production improves more.

  Further, the support is natural sponge, synthetic sponge, activated carbon, ceramic, ion exchange resin, zeolite, foam stone, molten slag, cellulose acetate fiber, and glass beads, carbon, silica gel, sand, alumina, molecular sieve, and One or more selected from the group consisting of titanium oxides are preferred. Thereby, it is considered that the above-described effect can be obtained more reliably.

  Or it is also preferable that the said support body is at least 1 sort (s) selected from the waste, shellfish, and bone which contain the said calcium as a component. Thereby, culture and detoxification can be performed at the same time, which is considered to be more efficient.

  Furthermore, in the production method, the microorganism of the genus Thermococcus is preferably Thermococcus kodakarensis. Thereby, it is considered that the above-described effect can be obtained more reliably.

  Furthermore, it is preferable that Thermococcus kodakarensis is Thermococcus kodakarensis KOD1 (Deposit organization: National Institute of Advanced Industrial Science and Technology, Patent Organism Depositary, Accession Number: FERM P-15007). Thereby, it is considered that the above-described effect can be obtained more reliably.

  In addition, the hydrogen production apparatus according to another aspect of the present invention includes a culture tank for culturing a microorganism of the genus Thermococcus using a culture solution to which a carbon source is added, acetic acid generated during hydrogen production, and calcium as a component. It is characterized by comprising at least a detoxification tank that detoxifies using at least one selected from wastes, shellfish and bones to be contained.

  Furthermore, in the manufacturing apparatus, it is preferable that the culture tank and the detoxification tank are integrated.

  The present invention will be described more specifically with reference to the following examples. However, the scope of the present invention is not limited to these examples.

Example 1
In the examples, a hydrogen production apparatus (culture apparatus) whose outline is shown in FIG. 2 was used.

<Preparation of medium>
(Basic medium)
An aqueous solution having a salt concentration of 3% with the addition of salt was used as a basal medium.

(Pre-culture medium)
The following medium based on a medium (MA medium) obtained by adding 0.5% (w / v) each of yeast extract and tryptone to artificial sea salt was prepared. Tryptone is obtained by partially hydrolyzing a protein with trypsin. Marine art is a mixture of salts containing the same components as seawater. In addition, although content of each component in the following culture medium composition is set to “% (w / v)”, even if it is converted to “% (w / w)”, there is no significant difference in numerical values.

(Medium composition 1)
・ 0.39% (w / v) Marine Art SF (manufactured by Senju Pharmaceutical Co., Ltd.), diluted 0.8 times the specified amount ・ 0.5% (w / v) dry yeast extract, specially made for microbial culture (Made by Co., Ltd.)
・ 0.5% (w / v) tryptone, specially made for microorganism medium
・ 0.5% (w / v) sodium pyruvate (manufactured by Nacalai Tesque)
(The balance is water, the pH of the system is 6.4)
<Culture operation>
(Preparation)
The culture medium (1) and detoxification tank (2) shown in FIG.

(Pre-culture operation)
In the pre-culture, 100 ml of the medium composition 1 is filled in a sealed glass container having an internal volume of about 100 ml, and the anaerobic hyperthermophilic bacterium Thermococcus kodakararensis KOD1 has an absorbance at a wavelength of 660 nm of OD660 = 0.1. Inoculated with 1 ml of suspension water of the present bacterium thus adjusted and cultured at 85 ° C. for 20 hours.

(Main culture and detoxification operation)
As shown in FIG. 2, 500 g of potato and 100 g of rice bran were added as a carbon source (6) to a 20 L culture tank (1) that had been sterilized, in addition to the culture medium of the basal medium. A total amount of 2000 ml of the culture solution in which KOD1 was precultured was inoculated there. At the same time, 240 g of a synthetic sponge (hereinafter also simply referred to as a sponge) sterilized with 100 ° C. hot water for 30 minutes was added as a support (3), and main culture was started.

  On the other hand, 1500 g of oyster shells were put into the 18 L detoxification tank (2) together with the basal medium. In this example, commercially available tropical fish breeding oyster shells and soil modified fertilizer oyster shells were mixed at a ratio of about 2: 1.

  The culture tank (1) and the detoxification tank (2) are connected by a silicon tube (10), and the medium is sent from the detoxification tank (2) to the culture tank (1) by a pump (7) in a constant amount. The medium overflowing from 1) was sent again to the detoxification tank (2), and the medium was circulated.

  In the main culture, continuous culture was performed for 680 hours while maintaining the culture medium temperature of the culture tank (1) and the detoxification tank (2) at 85 ° C. with a heater.

  As a result, 5.8 L of hydrogen could be obtained.

  In addition, about the measurement of hydrogen amount, the biogas produced in the culture tank (1) by the said culture | cultivation was collected by the biogas collection bottle (11) through the silicon tube (10) as shown in FIG. Then, the biogas pushed out from the collection bottle (11) was passed through the fuel cell (8) (manufactured by FC-R & D, HPFCRD-0505), and the generated voltage was measured with the recorder (9). The relationship between the hydrogen concentration by the fuel cell and the generated voltage was measured in advance, and the hydrogen concentration was calculated from the value of the generated voltage.

  In addition, during the main culture, as shown in Table 1 below, the hydrogen generation rate was measured by changing the circulating amount of the medium (4 L / hour to 20 L / hour). As a result, the hydrogen production rate became maximum at a circulation rate of 15 L / hour, which was 22 mL / hour.

  Hydrogen generation continued after 680 hours, but the culture was discontinued because the hydrogen generation rate began to decrease.

  Although acetic acid detoxification has been proved by continuous cultivation for a long time, the concentration of acetic acid in the culture medium after culturing was measured by ion chromatography after removing the medium in the culture tank. As a result, acetic acid could not be detected as expected.

  From the above, it has been confirmed that the production method using the microorganism of the present invention makes it possible to produce hydrogen continuously and efficiently by detoxifying acetic acid that hinders continuous culture.

DESCRIPTION OF SYMBOLS 1 Culture tank 2 Detoxification tank 3 Support body 4 Waste, shellfish, and bone containing as calcium component 5 Gas extraction means 6 Carbon source 7 Pump 8 Fuel cell 9 Recorder 10 Silicon tube 11 Biogas collection bottle

Claims (8)

Culturing a microorganism of the genus Thermococcus using a culture solution to which a carbon source is added, to cause the microorganism of the genus Thermococcus to produce hydrogen, and
Detoxifying acetic acid produced during hydrogen production using at least one selected from waste, shellfish, and bone, containing calcium as a component;
A method for producing hydrogen comprising:   The method for producing hydrogen according to claim 1, wherein during the cultivation, a support is placed and cultured to produce hydrogen.   The support is natural sponge, synthetic sponge, activated carbon, ceramic, ion exchange resin, zeolite, foamed stone, molten slag, cellulose acetate fiber, and glass beads, carbon, silica gel, sand, alumina, molecular sieve, and titanium oxidation. The manufacturing method of hydrogen of Claim 2 which is 1 type, or 2 or more types chosen from the group which consists of a thing.   The method for producing hydrogen according to claim 2, wherein the support is at least one selected from waste, shellfish, and bone containing the calcium as a component.   The method for producing hydrogen according to any one of claims 1 to 4, wherein the microorganism of the genus Thermococcus is Thermococcus kodakarensis.   6. The method for producing hydrogen according to claim 5, wherein Thermococcus kodakarensis is Thermococcus kodakarensis KOD1 (Deposit organization: National Institute of Advanced Industrial Science and Technology, Patent Biodeposition Center, Deposit Number: FERM P-15007). . A culture vessel for culturing a microorganism of the genus Thermococcus using a culture solution to which a carbon source is added;
An apparatus for producing hydrogen comprising at least a detoxification tank that detoxifies acetic acid produced during hydrogen production using at least one selected from waste, shellfish, and bone, containing calcium as a component.   The hydrogen production apparatus according to claim 7, wherein the culture tank and the detoxification tank are integrated.

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