Reaction device and method for producing product

Abstract

The present disclosure provides a technique that is advantageous from the viewpoint of suppressing deterioration of an enzyme while continuously activating a coenzyme. A reaction device (1a) according to the present disclosure comprises an enzyme reactor (10), an enzyme (15), and an electrochemical reactor (20). The enzyme (15) is disposed inside the enzyme reactor (10). In the reaction device (1a), the enzyme reactor (10) and the electrochemical reactor (20) are configured such that a reaction liquid (R) circulates between the enzyme reactor (10) and the electrochemical reactor (20). The reaction liquid (R) contains a substrate and a coenzyme. The enzyme (15) is, for example, an oxidoreductase. The substrate is oxidized or reduced by the enzyme (15). The coenzyme restores the activity of the enzyme (15) after the enzyme has reacted with the substrate.

Description

Reactor and method for producing product

[0001] The present disclosure relates to a reactor and a method for producing a product.

[0002] Enzymes are traditionally known as one of the catalysts in living organisms, and a substrate is converted into a product, which is a chemically different substance, by the catalytic action of the enzyme.

[0003] An example of an enzymatic reaction is an enzymatic reaction using glucose dehydrogenase. This enzymatic reaction requires a substrate, glucose, and a coenzyme, nicotinamide adenine dinucleotide (NAD). In this enzymatic reaction, the substrate is converted into gluconolactone, and the coenzyme is converted into reduced nicotinamide adenine dinucleotide (NADH).

[0004] For example, Patent Document 1 describes an electrochemical reaction device that contains glucose dehydrogenase and NAD and includes a first tank in which a working electrode is placed, and a second tank in which a counter electrode is placed. In this electrochemical reaction device, glucose dehydrogenase functions as a catalyst, and NAD participates as a coenzyme to cause an enzyme reaction. In addition, when a voltage is applied between the working electrode and the counter electrode, NADH produced by the enzyme reaction is oxidized to produce oxidized nicotinamide adenine dinucleotide (NADH). + In this way, NAD is regenerated by applying a voltage between the working electrode and the counter electrode, and glucose decomposition can continue even if the liquid in the first tank does not contain a large amount of NAD.

[0005] Patent Document 2 describes an enzyme reaction apparatus. This enzyme reaction apparatus includes a cylindrical container and a separation membrane. An immobilized enzyme is supported on the inner wall surface of the cylindrical container. In the immobilized enzyme, the enzyme is immobilized on water-dispersible high molecular weight polymer particles. The separation membrane does not allow the immobilized enzyme to pass through, but allows the enzyme reaction product to pass through.

[0006] Patent Document 3 describes an enzyme reaction apparatus. This enzyme reaction apparatus includes a reactor, multiple adsorbers, a desorption liquid supply system, a coenzyme supply system, and a reaction liquid discharge system. The adsorbers recover the coenzyme from the reaction liquid produced in the reactor. The desorption liquid supply system supplies the adsorbers with a desorption liquid to desorb the coenzyme from the adsorbent. This allows the coenzyme to be reused.

[0007] International Publication No. 2023 / 074453 Japanese Patent Application Laid-Open No. 60-27380 Japanese Patent Application Laid-Open No. 61-205499

[0008] The techniques described in the above patent documents need to be reconsidered from the viewpoint of continuously activating a coenzyme while suppressing enzyme degradation. Therefore, the present disclosure provides a technique that is advantageous from the viewpoint of continuously activating a coenzyme while suppressing enzyme degradation.

[0009] The present disclosure provides a reaction device comprising: an enzyme reactor; an enzyme disposed inside the enzyme reactor; and an electrochemical reactor, wherein the enzyme reactor and the electrochemical reactor are configured so that a reaction solution circulates between the enzyme reactor and the electrochemical reactor, the reaction solution contains a substrate to be oxidized or reduced by the enzyme and a coenzyme that restores activity of the enzyme after reaction with the substrate, the enzyme is disposed so as to remain inside the enzyme reactor when the reaction solution passes through the enzyme reactor, and the electrochemical reactor electrochemically restores activity of the coenzyme.

[0010] The reaction apparatus of the present disclosure is advantageous from the viewpoint of continuously activating the coenzyme while suppressing the deterioration of the enzyme.

[0011] FIG. 1 is a schematic diagram of an example of a reaction apparatus according to an embodiment. FIG. 2 is a flowchart showing an example of a method for producing a product according to an embodiment. FIG. 3 is a diagram showing another example of a reaction apparatus according to an embodiment. FIG. 4 is a diagram showing yet another example of a reaction apparatus according to an embodiment. FIG. 5 is a diagram showing yet another example of a reaction apparatus according to an embodiment. FIG. 6 is a diagram showing yet another example of a reaction apparatus according to an embodiment. FIG. 7 is a diagram showing yet another example of a reaction apparatus according to an embodiment. FIG. 8 is a diagram showing yet another example of a reaction apparatus according to an embodiment. FIG. 9 is a diagram showing yet another example of a reaction apparatus according to an embodiment. FIG. 10 is a graph showing the relationship between absorbance and reaction time in a reference example. FIG. 11 is a graph showing the fructose concentration before and after reaction in examples and comparative examples.

[0012] (Findings that form the basis of the present disclosure) As described in Patent Document 1, the coenzyme can be regenerated by applying a voltage between the working electrode and the counter electrode, and the coenzyme can be repeatedly used for the enzyme reaction. On the other hand, when the enzyme is affected by the electric field generated by applying a voltage between the working electrode and the counter electrode, the enzyme deteriorates, making it difficult to repeatedly use the enzyme.

[0013] Therefore, the present inventors have conducted extensive research into the configuration of a reaction device that is advantageous from the viewpoint of continuously activating a coenzyme while suppressing enzyme degradation. As a result, it has been newly discovered that a reaction device equipped with a predetermined enzyme reactor and an electrochemical reactor can continuously activate a coenzyme while suppressing enzyme degradation. Based on this new finding, the present inventors have completed the reaction device of the present disclosure. In this disclosure, "continuously" means "repeatedly."

[0014] (Embodiments of the Present Disclosure) Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, the arrangement and connection of the components, steps, and the order of steps shown in the following embodiments are merely examples and are not intended to limit the scope of the claims. Furthermore, each drawing is not necessarily an exact illustration. In each drawing, substantially identical configurations are assigned the same reference numerals, and redundant explanations may be omitted or simplified. Furthermore, below, terms indicating the relationship between elements, such as "parallel" and "perpendicular," terms indicating the shape of elements, such as "rectangular," and numerical ranges do not only indicate the strict meaning, but also include substantially equivalent ranges, for example, differences of a few percent. These embodiments shown as comprehensive or specific examples may be realized using a system, an apparatus, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized using any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0015] (Embodiment) Hereinafter, an embodiment will be specifically described with reference to FIGS. 1 to 9. FIG.

[0016] FIG. 1 is a schematic diagram illustrating an example of a reaction apparatus according to an embodiment. As shown in FIG. 1, the reaction apparatus 1a includes an enzyme reactor 10, an enzyme 15, and an electrochemical reactor 20. The enzyme 15 is disposed inside the enzyme reactor 10. In the reaction apparatus 1a, the enzyme reactor 10 and the electrochemical reactor 20 are configured so that a reaction solution R circulates between the enzyme reactor 10 and the electrochemical reactor 20. The reaction solution R contains a substrate and a coenzyme. The reaction solution R may contain, for example, a solvent such as water, a buffer such as Good's buffer, a salt such as sodium chloride, and a pH adjuster such as hydrochloric acid, as necessary. The enzyme 15 is, for example, an oxidoreductase. The substrate is oxidized or reduced by the enzyme 15. The substrate may be a sugar such as fructose or glucose, or a protein such as ovomucoid contained in egg white or casein contained in milk. The coenzyme restores the activity of the enzyme 15 after it has reacted with the substrate. Examples of coenzymes are NAD and nicotinamide adenine dinucleotide phosphate (NADP). The enzyme 15 is arranged so as to remain inside the enzyme reactor 10 when the reaction solution R passes through the enzyme reactor 10. The electrochemical reactor 20 electrochemically restores the activity of the coenzyme contained in the reaction solution R.

[0017] By circulating the reaction solution R between the enzyme reactor 10 and the electrochemical reactor 20, the coenzyme contained in the reaction solution R can be continuously activated by the electrochemical reactor 20. In addition, since the enzyme 15 is arranged so as to remain inside the enzyme reactor 10, the enzyme 15 is not affected by the electrochemical reactor 20, and deterioration of the enzyme 15 can be suppressed. Therefore, the enzyme 15 can be used repeatedly.

[0018] 1, the reaction apparatus 1a includes, for example, a storage tank 40, an agitator 41, and a motor 42. A reaction liquid R is stored inside the storage tank 40. The agitator 41 and the motor 42 are connected, and the agitator 41 is rotated by the motor 42. The agitator 41 is disposed inside the storage tank 40, and the reaction liquid R is agitated by the rotation of the agitator 41. The agitator 41 may be configured as a magnetic stirrer.

[0019] The reaction apparatus 1a includes, for example, a flow path 31p, a valve 31v, a flow path 32p, a flow path 33p, and a pump 36. The flow path 31p connects the reservoir 40 and the electrochemical reactor 20. The valve 31v is disposed in the flow path 31p. The flow path 32p connects the electrochemical reactor 20 and the enzyme reactor 10. The flow path 33p connects the electrochemical reactor 20 and the reservoir 40. The pump 36 is disposed in, for example, the flow path 33p. The pump 36 may be disposed in the flow path 31p or the flow path 32p.

[0020] When the pump 36 is operated with the valve 31v open, the reaction solution R stored in the storage tank 40 passes through the flow path 31p, the electrochemical reactor 20, the flow path 32p, the enzyme reactor 10, and the flow path 33p, and returns to the storage tank 40. In this way, the reaction solution R can circulate between the enzyme reactor 10 and the electrochemical reactor 20.

[0021] The reaction apparatus 1a includes, for example, a pH meter 43, a pH measurement electrode 43e, a signal line 43s, a supply device 50, a path 52, and a valve 52v. The pH meter 43 measures the pH of the liquid to be measured based on the potential difference between the reference electrode and the glass electrode in the pH measurement electrode 43e. The pH measurement electrode 43e is immersed in the reaction liquid R stored inside the storage tank 40. Therefore, the pH of the reaction liquid R is measured by the pH meter 43.

[0022] The supplier 50 is connected to the reservoir 40 via a path 52 and supplies a pH adjuster toward the reservoir 40. A valve 52v is disposed on the path 52. A signal for controlling the opening and closing of the valve 52v is sent to the valve 52v through a signal line 43s. This controls the opening and closing of the valve 52v. Examples of pH adjusters are hydrochloric acid, sodium hydroxide, and malic acid.

[0023] The electrochemical reactor 20 is not limited to a specific configuration as long as it can electrochemically restore the activity of the coenzyme. As shown in FIG. 1 , the electrochemical reactor 20 includes a first chamber 21, a second chamber 22, a membrane 23, and a voltage application device 26. The reaction solution R passes through the first chamber 21. For example, flow paths 31p and 32p are connected to the first chamber 21. A working electrode 25a is disposed in the first chamber 21. A counter electrode 25b is disposed in the second chamber 22. The membrane 23 separates the first chamber 21 from the second chamber 22. The membrane 23 prevents the permeation of the coenzyme and substrate contained in the reaction solution R and has ion conductivity. The voltage application device 26 is a device for applying a voltage between the working electrode 25a and the counter electrode 25b.

[0024] When a voltage is applied between the working electrode 25a and the counter electrode 25b by the voltage application device 26, an oxidation-reduction reaction occurs at the working electrode 25a and the counter electrode 25b, and the coenzyme is activated.

[0025] As shown in FIG. 1, the first chamber 21 and the second chamber 22 contain an electrolyte solution E. This facilitates a predetermined oxidation-reduction reaction at the working electrode 25a and the counter electrode 25b. For example, NAD + is reduced to produce NADH. Examples of electrolytes used in the electrolyte solution E include sodium chloride and potassium chloride. For example, the electrolyte solution E contained in the second compartment 22 does not contain a substrate or a coenzyme.

[0026] The membrane 23 is not limited to a specific membrane as long as it blocks the permeation of the coenzyme and the substrate and has ion conductivity. The membrane 23 may contain, for example, a polymer having a perfluoro side chain containing a sulfonic acid group. This configuration allows certain ions such as protons to move quickly through the membrane 23, and the oxidation-reduction reaction for activating the coenzyme can be efficiently carried out at the working electrode 25 a and the counter electrode 25 b.

[0027] The materials forming the surfaces of the working electrode 25a and the counter electrode 25b are not limited to specific materials. The surfaces of the working electrode 25a and the counter electrode 25b include, for example, a conductive material. The conductive material is, for example, a material that does not decompose when the conductive material is oxidized. Examples of conductive materials include carbon materials, conductive polymers, semiconductor materials, and metal materials. Examples of carbon materials include carbon nanotubes, Ketjen Black (registered trademark), glassy carbon, graphene, fullerene, carbon fiber, carbon fabric, and carbon aerogel. Examples of conductive polymers include polyaniline, polyacetylene, polypyrrole, poly(3,4-ethylenedioxythiophene), poly(p-phenylenevinylene), polythiophene, and poly(p-phenylene sulfide). Examples of semiconductor materials include silicon, germanium, indium tin oxide (ITO), titanium oxide, copper oxide, and silver oxide. Examples of metallic materials include gold, platinum, silver, titanium, aluminum, tungsten, copper, iron, and palladium. The working electrode 25a may be a glassy carbon electrode, and the counter electrode 25b may be a platinum electrode.

[0028] The surface area of ​​the counter electrode 25b is, for example, larger than the surface area of ​​the working electrode 25a.

[0029] 1, for example, a reference electrode 25c is disposed in the first chamber 21. The reference electrode 25c facilitates stabilization of the potential difference between the working electrode 25a and the counter electrode 25b. The reference electrode 25c is, for example, a silver / silver chloride electrode.

[0030] The enzyme reactor 10 is not limited to a specific configuration as long as an enzyme 15 is disposed therein and the enzyme 15 is disposed so as to remain inside the enzyme reactor 10 when the reaction solution R passes through the enzyme reactor 10. The enzyme reactor 10 is, for example, a tubular reactor. The reaction solution R is supplied to the enzyme reactor 10 so as to pass through the enzyme reactor 10 in, for example, a direction opposite to the direction of gravity.

[0031] The enzyme reactor 10 has, for example, a filter 11. The filter 11 allows the coenzyme and substrate to pass through when the reaction solution R passes through the enzyme reactor 10, and prevents the enzyme 15 from passing through. As a result, in the enzyme reactor 10, the coenzyme and substrate are removed from the inside of the enzyme reactor 10, while the enzyme 15 remains inside the enzyme reactor 10. The filter 11 allows, for example, the product produced by the enzyme reaction involving the enzyme 15 to pass through. In this case, it is easy to recover the product obtained by the enzyme reaction.

[0032] The enzyme reactor 10 includes, for example, a pair of filters 11. The filters 11 are arranged, for example, at the inlet and outlet of the enzyme reactor 10 in the flow of the reaction liquid R.

[0033] The filter 11 is, for example, a porous membrane or a fiber-containing membrane having a predetermined average pore size. The average pore size of the filter 11 is not limited to a specific value as long as it allows the coenzyme and substrate to pass through while preventing the enzyme 15 from passing through. As described below, for example, when the enzyme 15 is supported on the surface of carrier particles, the average pore size of the filter 11 is smaller than half the average particle size of the carrier particles. In this case, it is easier to prevent the enzyme 15 from passing through while allowing the coenzyme and substrate to pass through. The average pore size of the filter 11 can be determined, for example, according to a gas adsorption method.

[0034] The enzyme 15 is supported on the surface of, for example, carrier particles. In this case, the enzyme 15 can be more easily retained inside the enzyme reactor 10 when the reaction solution R passes through the enzyme reactor 10. The enzyme 15 may be placed alone inside the enzyme reactor 10 without being supported on a carrier.

[0035] The carrier particles are not limited to specific particles as long as they can support the enzyme 15 on their surfaces. The carrier particles include, for example, an organic polymer or a non-metallic inorganic material. In this case, the activity of the enzyme 15 is likely to be maintained at a high level, and the enzyme 15 can be easily used repeatedly. An example of an organic polymer is an ion exchange resin. Non-metallic inorganic materials include inorganic materials such as glass and ceramics, but do not include metals.

[0036] The average particle size of the carrier particles is not limited to a specific value. The carrier particles have an average particle size of, for example, 1 micrometer to 5 millimeters. In this case, the enzyme 15 can be more easily retained inside the enzyme reactor 10 when the reaction solution R passes through the enzyme reactor 10. In addition, the amount of enzyme 15 filled in the enzyme reactor 10 tends to be large. The average particle size of the carrier particles is, for example, the median diameter in a particle size distribution based on the number of particles.

[0037] A product can be produced using the above-described reaction apparatus 1a. The method for producing the product includes passing a reaction solution R containing a substrate and a coenzyme through an electrochemical reactor 20 and an enzyme reactor 10. This allows an enzyme reaction to occur continuously in the enzyme reactor 10, and also electrochemically restores the activity of the coenzyme in the electrochemical reactor 20. As described above, the enzyme 15 is arranged so as to remain inside the enzyme reactor 10 when the reaction solution R passes through the enzyme reactor 10.

[0038] 2 is a flowchart showing an example of a method for producing a product. As shown in FIG. 2, in step S101, a reaction solution R is prepared. For example, with the valve 31v closed, a substrate and a coenzyme are added to the storage tank 40 so as to have predetermined concentrations, thereby preparing the reaction solution R. Next, in step S102, the valve 31v is opened, and application of a voltage between the working electrode 25a and the counter electrode 25b and operation of the pump 36 are initiated. As a result, the reaction solution R in the storage tank 40 passes through the electrochemical reactor 20 and the enzyme reactor 10 and is returned to the storage tank 40. In this way, the reaction solution R circulates between the enzyme reactor 10 and the electrochemical reactor 20.

[0039] In the enzyme reactor 10, the substrate is oxidized or reduced by the catalytic action of the enzyme 15 to produce a product. As a result, the enzyme 15 is rendered inactive, but the activity of the enzyme 15 is restored by the action of the coenzyme contained in the reaction solution R. On the other hand, the coenzyme that restored the activity of the enzyme 15 temporarily loses its activity, but the activity of the coenzyme is electrochemically restored in the electrochemical reactor 20. Therefore, a product is continuously produced by the enzyme reaction involving the enzyme 15.

[0040] Next, in step S103, the pH of the reaction solution R in the storage tank 40 is measured by the pH meter 43. Next, in step S104, it is determined whether the pH of the reaction solution R is within a predetermined range. For example, the optimum pH of the enzymatic reaction involving the enzyme 15 is included in this predetermined range.

[0041] If the result of the determination in step S104 is negative, the process proceeds to step S108, where the amount of pH adjuster to be added to the reaction solution R is calculated. In this calculation, for example, the amount of pH adjuster to be added is determined based on the difference between the measured pH of the reaction solution R and the value corresponding to the above-mentioned optimal pH. For example, the larger this difference, the larger the amount of pH adjuster to be added. Next, the process proceeds to step S109, where the pH adjuster is added. For example, a control signal to open valve 52v is sent from signal line 43s, opening valve 52v, and an amount of pH adjuster corresponding to the calculation result in step S108 is supplied to storage tank 40 from supplier 50 via path 52. In this way, the pH of reaction solution R is adjusted to the above-mentioned optimal pH or a value close to the optimal pH.

[0042] If the determination result in step S104 is positive, or if step S109 is completed, the process proceeds to step S105, and after a predetermined period of time has elapsed, the process proceeds to step S106. The predetermined period of time is set, for example, so that the pH of the reaction solution R falls within a predetermined range in about 10 minutes. A determination is made as to whether a specific time (e.g., 4 hours) has elapsed since the start of operation of the pump 36. If the result of this determination is negative, the process returns to step S103; if the result of this determination is positive, the process proceeds to step S107, where the liquid containing the product is recovered, and production of the product is completed.

[0043] 2 may be automatically controlled using a digital computer having a memory storing a program for executing the process and a processor that reads the program and performs calculations. In this automatic control, the types of substrate and coenzyme, the volume of the reaction solution R, the type of working electrode 25a, the voltage applied between the working electrode 25a and the counter electrode 25b, the optimal pH of the enzyme involved in the enzyme 15, the overall processing time, and the like can be used as input parameters.

[0044] The reaction apparatus 1a can be modified from various viewpoints. FIG. 3 is a diagram showing another example of a reaction apparatus according to an embodiment. The reaction apparatus 1b shown in FIG. 3 is configured similarly to the reaction apparatus 1a except for the parts that will be particularly described. The same reference numerals are used to designate components that are the same as or correspond to the components of the reaction apparatus 1a, and detailed description thereof will be omitted. The description of the reaction apparatus 1a also applies to the reaction apparatus 1b unless there is a technical contradiction.

[0045] As shown in Fig. 3, in the reaction device 1b, the storage tank 40 in the reaction device 1a and the electrochemical reactor 20 are integrated. In addition to the working electrode 25a, a stirrer 41 and a pH measurement electrode 43e are arranged in the first chamber 21 of the electrochemical reactor 20. The reaction device 1b is equipped with a flow path 34p and a valve 34v. The flow path 34p connects the first chamber 21 of the electrochemical reactor 20 and the enzyme reactor 10. The valve 34v is arranged in the flow path 34p.

[0046] 4 is a diagram showing yet another example of a reaction apparatus according to an embodiment. As shown in FIG. 4, the reaction solution R may be supplied to the enzyme reactor 10 so as to pass through the enzyme reactor 10 in the direction of gravity, for example.

[0047] FIG. 5 is a diagram showing yet another example of a reaction apparatus according to an embodiment. As shown in FIG. 5, a temperature regulator 16 may be disposed around the enzyme reactor 10. Enzymes generally tend to have high activity at temperatures between 30°C and 50°C and may be inactivated if exposed to an environment of 75°C or higher for a long period of time. Therefore, from the viewpoint of stabilizing the activity of the enzyme 15 and promoting the enzymatic reaction, it is important to maintain the temperature around the enzyme 15 within a predetermined range. Therefore, the temperature regulator 16 tends to stabilize the activity of the enzyme 15 and promote the enzymatic reaction. The temperature regulator 16 includes, for example, a coiled heat transfer tube through which a heat medium such as water flows. The temperature regulator 16 may include a Peltier element.

[0048] The temperature of the reaction solution R or the enzyme 15 may be adjusted by disposing a part of the reaction device 1a inside a thermostatic bath.

[0049] 6 is a diagram showing yet another example of a reaction apparatus according to an embodiment. As shown in FIG. 6, the reference electrode 25c may be omitted. When the distance between the working electrode 25a and the counter electrode 25b is short, for example, when the distance is within about 1 cm, the reference electrode 25c may be omitted.

[0050] FIG. 7 is a diagram showing yet another example of a reaction apparatus according to an embodiment. As shown in FIG. 7 , the electrochemical reactor 20 may include multiple working electrodes 25 a. In this case, for example, one counter electrode 25 b may be disposed between a pair of working electrodes 25 a. For example, if the electrochemical reactor 20 includes three working electrodes 25 a, the working electrodes 25 a and the counter electrodes 25 b may be disposed in the following order: working electrode 25 a, counter electrode 25 b, working electrode 25 a, counter electrode 25 b, and working electrode 25 a. For example, the multiple working electrodes 25 a are connected in parallel to the voltage application device 26, and the multiple counter electrodes 25 b are connected in parallel.

[0051] Fig. 8 is a diagram showing yet another example of a reaction apparatus according to an embodiment. In Fig. 8, a pH measurement electrode 43e is disposed in the first chamber 21, and a pH meter 43 measures the pH of the reaction solution R in the first chamber 21. A supply device 50 is connected to the flow path 32p and can supply a pH adjuster to the reaction solution R that passes through the first chamber 21 and flows toward the enzyme reactor 10.

[0052] 9 is a diagram showing yet another example of a reaction apparatus according to an embodiment. As shown in Fig. 9, the first chamber 21 of the electrochemical reactor 20 and the enzyme reactor 10 may be directly connected, or, for example, the first chamber 21 and the inside of the enzyme reactor 10 may be separated by a filter 11. Even with such a configuration, the enzyme 15 remains inside the enzyme reactor 10, is less susceptible to the influence of the electrochemical reactor 20, and deterioration of the enzyme 15 can be suppressed.

[0053] The overall configuration of the reaction device is described in Figures 1 and 3, the configuration related to the enzyme reactor 10 is described in Figures 4 and 5, and the configuration related to the electrochemical reactor 20 is described in Figures 6 to 9. The reaction device may be configured by appropriately combining these configurations.

[0054] (Other Embodiments) The reaction apparatus and the method for producing a product have been described based on the embodiments. However, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, various modifications that a person skilled in the art can make to the embodiments and other embodiments formed by combining some of the components of the embodiments are included in the scope of the present disclosure.

[0055] (Additional Note) From the above description, the following techniques are disclosed.

[0056] (Technology 1) A reaction device comprising: an enzyme reactor; an enzyme arranged inside the enzyme reactor; and an electrochemical reactor, wherein the enzyme reactor and the electrochemical reactor are configured so that a reaction solution circulates between the enzyme reactor and the electrochemical reactor, the reaction solution contains a substrate to be oxidized or reduced by the enzyme and a coenzyme that restores activity of the enzyme after reaction with the substrate, the enzyme is arranged so as to remain inside the enzyme reactor when the reaction solution passes through the enzyme reactor, and the electrochemical reactor electrochemically restores activity of the coenzyme.

[0057] (Technology 2) The electrochemical reactor is the reaction device according to Technology 1, comprising: a first chamber through which the reaction solution passes and in which a working electrode is disposed; a second chamber in which a counter electrode is disposed; a membrane separating the first chamber from the second chamber, preventing permeation of the coenzyme and the substrate, and having ion conductivity; and a voltage application device for applying a voltage between the working electrode and the counter electrode.

[0058] (Technology 3) The reaction device according to Technology 2, wherein the first chamber and the second chamber contain an electrolyte solution.

[0059] (Technology 4) The reaction apparatus according to Technology 2 or 3, wherein the membrane contains a polymer having a perfluoro side chain containing a sulfonic acid group.

[0060] (Technology 5) The reaction device according to any one of Technologies 1 to 4, wherein the enzyme is supported on the surface of a carrier particle.

[0061] (Technology 6) The reaction device according to Technology 5, wherein the support particles comprise an organic polymer or a non-metallic inorganic material.

[0062] (Technology 7) The reaction apparatus according to Technology 5 or 6, wherein the carrier particles have an average particle size of 1 micrometer to 5 millimeters.

[0063] (Technology 8) The reaction apparatus according to any one of Technologies 1 to 7, wherein the enzyme reactor further comprises a filter that allows the coenzyme and the substrate to pass through and prevents the enzyme from passing through when the reaction solution passes through the enzyme reactor.

[0064] (Technology 9) The reaction apparatus according to Technology 8, wherein the enzyme is supported on the surface of carrier particles, and the filter has an average pore size smaller than half the average particle size of the carrier particles.

[0065] (Technology 10) A method for producing a product, comprising: passing a reaction solution containing a substrate to be oxidized or reduced by an enzyme and a coenzyme that restores activity of the enzyme after reaction with the substrate through an electrochemical reactor and an enzyme reactor, thereby causing an enzyme reaction in the enzyme reactor and electrochemically restoring activity of the coenzyme in the electrochemical reactor; wherein the enzyme is arranged so as to remain inside the enzyme reactor when the reaction solution passes through the enzyme reactor.

[0066] (Technology 11) A method for producing a product, comprising: causing an enzymatic reaction in an enzyme reactor in which an enzyme is placed, with a reaction solution containing a substrate to be oxidized or reduced by an enzyme and a coenzyme; and electrochemically restoring the coenzyme in the reaction solution that has undergone the enzymatic reaction in an electrochemical reactor.

[0067] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the following examples.

[0068] Reference Example: A vessel was prepared, separated into two spaces, a first chamber and a second chamber, by a DuPont Nafion ion-exchange membrane, as shown in Figure 1 . Nafion is a registered trademark. A gold film was formed on a glass plate having a short side length of 10 mm and a long side length of 20 mm in plan view, and platinum was coated in a platinum chloride aqueous solution to prepare a working electrode. A silver / silver chloride electrode was prepared as a reference electrode. A platinum electrode was prepared as a counter electrode. The working electrode and reference electrode were placed in the first chamber of the vessel, and the counter electrode was placed in the second chamber of the vessel. The working electrode, reference electrode, and counter electrode were electrically connected to the working electrode terminal, reference electrode terminal, and counter electrode terminal of a potentiostat, respectively. 2-morpholinoethanesulfonic acid (MES) buffer solution was added to the second chamber of the vessel. This MES buffer solution did not contain substances corresponding to the substrate or coenzyme, and the pH of the MES buffer solution was 5.5. The first chamber of the container contained 5 mM of inactive coenzyme NAD + An MES buffer solution containing 100% ethanol was added to the container. The pH of this MES buffer solution was 5.5. The first chamber of the container was connected to the inlet of a pump via a rubber tube, and the outlet of the pump was connected to another container, an external container, via a rubber tube. In addition, the external container and the first chamber of the container were connected via a rubber tube to form a circulation path for the MES buffer solution.

[0069] The pump was operated with or without a voltage applied between the working electrode and the counter electrode to circulate the MES buffer solution between the first chamber and the external container. Samples of the MES buffer solution circulating between the first chamber and the external container were collected at the start of the pump operation, 2 hours after the start of the pump operation, 3 hours after the start of the pump operation, and 4 hours after the start of the pump operation. The absorbance of these samples at a wavelength of 340 nm was measured. The results are shown in Figure 10.

[0070] 10 is a graph showing the relationship between absorbance and reaction time in the Reference Example. As shown in FIG. 10, when no voltage was applied between the working electrode and the counter electrode (when E = 0 V), no change in absorbance was observed. On the other hand, when a voltage was applied between the working electrode and the counter electrode (when E = -0.9 V), the absorbance at a wavelength of 340 nm increased with the passage of time from the start of pump operation. The absorbance at a wavelength of 340 nm is correlated with the concentration of NADH. Therefore, the application of a voltage between the working electrode and the counter electrode increases the concentration of NADH. + It is thought that NADH was produced by reduction of coenzyme A. It was suggested that the activity of the coenzyme can be electrochemically restored by applying a voltage between the working electrode and the counter electrode.

[0071] <Examples and Comparative Examples> In the same manner as in the Reference Example, a container separated into two spaces, a first compartment and a second compartment, was prepared, and a working electrode and a reference electrode were placed inside the first compartment of the container, and a counter electrode was placed inside the second compartment of the container. The working electrode, the reference electrode, and the counter electrode were electrically connected to the working electrode terminal, the reference electrode terminal, and the counter electrode terminal of a potentiostat, respectively. A 2-morpholinoethanesulfonic acid (MES) buffer solution was added to the second compartment of the container. This MES buffer solution did not contain substances corresponding to the substrate and the coenzyme, and the pH of the MES buffer solution was 5.5. A 5 mM concentration of inactive coenzyme NAD was added to the first compartment of the container. + Then, MES buffer containing fructose at a concentration of about 350 mM was added, and the pH of this MES buffer was 5.5.

[0072] A column was prepared, packed with an enzyme-loaded carrier, in which the enzyme mannitol dehydrogenase was loaded onto DuPont's ion exchange resin Duolite A568. Duolite is a registered trademark of DuPont. The first chamber of the container was connected to the pump inlet with a rubber tube, and the pump outlet was connected to the column inlet with a rubber tube. In addition, the column outlet was connected to the first chamber of the container with a rubber tube, forming a circulation path for the MES buffer. Porous filters with an average pore size of 35 μm were placed near the column inlet and outlet. This filter allowed fructose and coenzymes to pass through while preventing the passage of the enzyme-loaded carrier.

[0073] The pump was operated with or without a voltage applied between the working electrode and the counter electrode to circulate the MES buffer between the first chamber and the column. Samples of the MES buffer circulating between the first chamber and the column were collected at the start of the pump operation and 24 hours after the start of the pump operation. The fructose concentrations in these samples were measured using a Sigma Fructose Colorimetric Assay Kit. The results are shown in Figure 11.

[0074] 11 is a graph showing the concentration of fructose before and after the reaction in the examples and comparative examples. The examples are the cases where a voltage was applied between the working electrode and the counter electrode, and the comparative examples are the cases where no voltage was applied between the working electrode and the counter electrode. As shown in FIG. 11, when no voltage was applied between the working electrode and the counter electrode, the concentration of fructose hardly changed, but when a voltage was applied between the working electrode and the counter electrode, the concentration of fructose decreased. This suggests that fructose is converted to mannitol by the action of the enzyme, producing mannitol.

[0075] The reaction apparatus of the present disclosure can be used as a reaction apparatus that utilizes an enzymatic reaction, such as converting fructose into mannitol.

[0076] 1a, 1b Reaction device 10 Enzyme reactor 11 Filter 15 Enzyme 20 Electrochemical reactor 21 First chamber 22 Second chamber 23 Membrane 25a Working electrode 25b Counter electrode 26 Voltage application device R Reaction solution

Claims

1. An enzymatic reactor, an enzyme disposed inside the enzymatic reactor, and an electrochemical reactor, wherein the enzymatic reactor and the electrochemical reactor are configured such that a reaction solution circulates between the enzymatic reactor and the electrochemical reactor, the reaction solution includes a substrate oxidized or reduced by the enzyme and a coenzyme that restores the activity of the enzyme after reacting with the substrate, the enzyme is disposed so as to remain inside the enzymatic reactor when the reaction solution passes through the enzymatic reactor, and the electrochemical reactor electrochemically restores the activity of the coenzyme. A reaction device.

2. The electrochemical reactor includes a first chamber through which the reaction solution passes and in which a working electrode is disposed, a second chamber in which a counter electrode is disposed, and a membrane that separates the first chamber and the second chamber, blocks the permeation of the coenzyme and the substrate, and has ion conductivity, and a voltage application device for applying a voltage between the working electrode and the counter electrode. The reaction device according to claim 1.

3. The reaction device according to claim 2, wherein an electrolyte solution is contained in the first chamber and the second chamber.

4. The reaction device according to claim 2, wherein the membrane includes a polymer having a perfluoro side chain containing a sulfonic acid group.

5. The reaction device according to claim 1, wherein the enzyme is supported on the surface of carrier particles.

6. The reaction device according to claim 5, wherein the carrier particles include an organic polymer or a non-metallic inorganic material.

7. The reaction device according to claim 5, wherein the carrier particles have an average particle size of 1 micrometer to 5 millimeters.

8. The enzymatic reactor further includes a filter that allows the coenzyme and the substrate to permeate when the reaction solution passes through the enzymatic reactor and blocks the permeation of the enzyme. The reaction device according to claim 1.

9. The enzyme is supported on the surface of carrier particles, and the filter has an average pore size smaller than half of the average particle size of the carrier particles. The reaction device according to claim 8.

10. A method for producing a product, wherein an enzymatic reaction is caused in an enzymatic reactor having an enzyme disposed therein using a reaction solution containing a substrate oxidized or reduced by the enzyme and a coenzyme, and the coenzyme in the reaction solution that has undergone the enzymatic reaction is electrochemically restored in an electrochemical reactor.

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