How to recover sugar

Abstract

The method that separates a fermentation inhibitor and sugar from a sugar solution that contains a fermentation inhibitor and recovers the sugar is a method that includes using water as an eluent to separate the fermentation inhibitor and the sugar based on the difference in retention time after having brought the sugar solution that contains a fermentation inhibitor into contact with a basic anion exchange resin packed in a column, and separately recovering a fraction that contains the fermentation inhibitor and a fraction that contains the sugar, in which the basic anion exchange resin is pretreated by a solution that contains a fermentation inhibitor.

Description

[Technical field]

[0001] The present invention relates to a method for recovering sugar. Specifically, the present invention relates to a method for recovering sugar by separating a fermentation inhibitor and sugar from a sugar liquid containing a fermentation inhibitor. This application claims priority based on Japanese Patent Application No. 2020-069876 filed on April 8, 2020, the contents of which are incorporated herein by reference. [Background technology]

[0002] In recent years, technologies for producing substances such as butanediol and other alcohols, amino acids, and lactic acid using microorganisms have been put to practical use. With the remarkable advances in gene analysis and editing technologies, it is now possible to manipulate the genes of microorganisms to produce substances that could not be produced by microorganisms before.

[0003] Generally, microorganisms assimilate carbohydrate raw materials to produce ethanol, amino acids, etc. In this case, if the carbohydrate raw material contains impurities at a certain concentration or higher, the fermentation yield of the target product decreases and the growth of the microorganisms is suppressed. Substances that have such effects on microorganisms are called fermentation inhibitors, and the type of substance and the concentration that causes inhibition vary greatly depending on the microorganism. In particular, genetically modified microorganisms tend to be more susceptible to the influence of inhibitors than microorganisms before recombination. Therefore, when using genetically modified microorganisms to produce a target substance, the carbohydrate raw material required for the culture and fermentation of the microorganism needs to contain a fermentation inhibitor content that is appropriate for the inhibitor resistance of the microorganism.

[0004] In the research and development of material production processes using microorganisms and in the practical application of such processes, food-based carbohydrate raw materials with low fermentation inhibitor content have been used so far. Specifically, glucose made from grains such as corn and potatoes has been mainly used. However, in order to widely disseminate material production systems using microorganisms in the future, it is desirable to use non-food carbohydrate raw materials instead of food-based carbohydrate raw materials in order to avoid the problem of competition with food. Representative examples of non-food carbohydrate raw materials include blackstrap molasses, a by-product generated by sugar factories, and cellulose-based carbohydrates produced from non-food biomass (wood, grass, etc.).

[0005] These non-food carbohydrate raw materials have a higher concentration of organic acids and contain coloring substances compared to food carbohydrate raw materials. It is known that these organic acids and coloring substances inhibit the cultivation and fermentation of microorganisms when they reach a certain concentration. Therefore, there is a demand for the development of technology to remove fermentation inhibitors for microorganisms from non-food carbohydrate raw materials and prepare carbohydrate raw materials suitable for substance production processes using microorganisms.

[0006] As techniques for removing microbial fermentation inhibitors from non-food carbohydrate raw materials, membrane separation techniques, adsorption removal techniques (see, for example, Patent Documents 1 to 3), sedimentation separation techniques, and the like have been researched and developed so far.

[0007] However, the techniques for removing microbial fermentation inhibitors from non-food carbohydrate raw materials described in Patent Documents 1 to 3 etc. leave room for improvement in terms of cost, separation efficiency and the like. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2009-95282 [Patent Document 2] Japanese Patent Application Publication No. 2011-78327 [Patent Document 3] Japanese Patent Application Publication No. 2014-83003 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above circumstances, and provides a method for separating a fermentation inhibitor and sugar from a sugar liquid containing a fermentation inhibitor, and recovering the sugar, which is inexpensive and has good separation efficiency. [Means for solving the problem]

[0010] That is, the present invention includes the following aspects. (1) Separating the fermentation inhibitors and sugar from the sugar solution containing the fermentation inhibitors; Applicable 1. A method for recovering sugar, comprising: Applicable The sugar solution containing the fermentation inhibitor was packed in a column. stomach After contacting with an ion exchange resin, water was used as the eluent, and the retention time was Applicable Fermentation inhibitors and Applicable Separate the sugar, Applicable A fraction containing fermentation inhibitors Applicable and recovering the fraction separately from the sugar-containing fraction, Applicable A method wherein the ion exchange resin is pretreated with a solution containing a fermentation inhibitor. (2) The above stomach Ion exchange resin is a strong basic anion exchange resin. or strongly acidic cation exchange resin The method according to (1) above, (3) The above stomach The method according to (1) or (2) above, wherein the average particle size of the ion-exchange resin is 100 μm or more and 600 μm or less. (4) Furthermore, When the fermentation inhibitor-containing solution is pre-treated, stomach A sugar liquid containing the fermentation inhibitor is contacted with an ion exchange resin to convert the fermentation inhibitor into the stomach and separating the fermentation inhibitor from the sugar by adsorption onto an ion exchange resin. Contains The method according to any one of (1) to (3) above. (5) The method according to any one of (1) to (4), wherein in the recovery, a fraction containing the sugar is recovered after a fraction containing the fermentation inhibitor. (6) The method according to any one of (1) to (5), wherein the sugar liquid containing the fermentation inhibitor contains a monosaccharide. (7) The method according to any one of (1) to (6), wherein the sugar liquid containing the fermentation inhibitor contains sucrose. (8) Furthermore, prior to said recovery: The method according to (7), comprising decomposing the sucrose into glucose and fructose. ( 9 ) The recovery is carried out at a temperature of 25°C or higher. in Implement the above (1) to ( 8 ). ( 10 The fermentation inhibitor is at least one selected from the group consisting of organic acids and coloring components. Contains , the above (1) to ( 9 ). Effect of the Invention

[0011] According to the method of the above aspect, it is possible to provide a method for separating a fermentation inhibitor and sugar from a sugar liquid containing a fermentation inhibitor, and recovering the sugar, which is inexpensive and has good separation efficiency. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing an apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 13 is a schematic diagram showing an apparatus according to another embodiment of the present invention. [Diagram 3] 1 is a chromatogram in Example 1. [Figure 4] 1 is a chromatogram (with color data) in Example 2. [Diagram 5] 1 is a chromatogram in Comparative Example 1. [Figure 6] 1 is a chromatogram in Example 3. [Figure 7] 1 is a chromatogram in Example 4. [Figure 8] Chromatogram in Example 5. [Figure 9]1 is a graph showing the relationship between the average particle size and the resolution of the anion exchange resin in Example 6. [Figure 10] Chromatogram (room temperature) in Example 7. [Figure 11] Chromatogram (40°C) in Example 7. [Figure 12] Chromatogram (50°C) in Example 7. [Figure 13] Chromatogram (60°C) in Example 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <Sugar solution containing fermentation inhibitors> In this specification, the term "sugar liquid containing a fermentation inhibitor" refers to a sugar liquid obtained from a biomass raw material. Biomass is broadly divided into three types: waste biomass, resource crops, and unused biomass. Examples of waste biomass include blackstrap molasses, waste paper, waste wood, waste building materials, and leftover food. Blackstrap molasses is a dark brown liquid that is a by-product during sugar manufacturing using sugar cane or sugar beet as a raw material. Examples of resource crops include sugar cane, sugar beet, potato, sweet potato, and corn. Examples of unused biomass include sugar cane bagasse, rice straw, wheat straw, rice husk, and corn residue (corn stover, corn cob, and corn hull). Hereinafter, unused biomass may be referred to as cellulosic biomass. These biomasses may be used alone or in combination of two or more. In addition, the sugar liquid containing a fermentation inhibitor may be an artificially synthesized sugar liquid obtained by mixing sugar (hereinafter also referred to as a carbohydrate component) and a fermentation inhibitor so as to have the same composition as the sugar liquid obtained from the above-mentioned biomass raw material. Among them, the sugar liquid containing a fermentation inhibitor to which the method of the present embodiment is applied is preferably a sugar liquid obtained from molasses or cellulosic biomass, and more preferably molasses.

[0014] When the sugar liquid containing the fermentation inhibitor is molasses, the main sugars in the molasses include sucrose, glucose, and fructose. When the sugar liquid containing the fermentation inhibitor is obtained from cellulosic biomass, examples of the main carbohydrate components of the sugar liquid include glucose, xylose, mannose, and the like. The sugar (carbohydrate component) recovered by the method of this embodiment is preferably a disaccharide or monosaccharide, more preferably a monosaccharide, and even more preferably at least one monosaccharide selected from the group consisting of glucose and fructose.

[0015] A method for obtaining a sugar liquid from cellulosic biomass can be appropriately selected from known techniques, such as a method in which a cellulosic biomass raw material is subjected to pretreatment such as crushing, steaming, or treatment with an acid or alkali, as necessary, and then saccharified using an enzyme (such as cellulase) to obtain a sugar liquid.

[0016] The fermentation inhibitor means a substance that inhibits the culture or fermentation of microorganisms in a substance production system using microorganisms with sugar solution as a raw material. Specific examples include organic acids, coloring components, saccharification by-products, and salts. Examples of organic acids include formic acid, acetic acid, and lactic acid. Examples of coloring components include melanoidin, polyphenols, and caramel. Saccharification by-products are substances that are produced as by-products when the above-mentioned biomass raw material is saccharified to produce sugar solution. Specific examples include furans such as furfural and 5-hydroxymethylfurfural (HMF). In particular, the method of the present embodiment is suitable for separating organic acids and coloring components from sugar solution.

[0017] <How to recover sugar solution> First Embodiment A method according to one embodiment of the present invention (hereinafter referred to as "the method of the present embodiment") is a method for separating a fermentation inhibitor and sugar from a sugar liquid containing a fermentation inhibitor, and recovering the sugar. The method of the present embodiment includes separately recovering a fraction containing the fermentation inhibitor and a fraction containing the sugar (hereinafter referred to as "recovery step"). In the recovery process, the sugar solution containing the fermentation inhibitor is contacted with a basic anion exchange resin packed in a column, and then water is used as the eluent to separate the fermentation inhibitor from the sugar based on the difference in retention time, and the fraction containing the fermentation inhibitor and the fraction containing the sugar are recovered separately. The basic anion exchange resin is pretreated with a solution containing a fermentation inhibitor.

[0018] According to the method of the present embodiment, as shown in the examples described later, it is possible to separate fermentation inhibitors and sugars from a sugar solution containing fermentation inhibitors with good separation efficiency, and to recover sugars. Furthermore, since the method of the present embodiment does not require regeneration of the ion exchange resin, continuous separation is possible.

[0019] Next, each step constituting the method of this embodiment will be described in detail below.

[0020] [Recovery process] In the recovery process, first, the sugar solution containing the fermentation inhibitor is contacted with a basic anion exchange resin packed in a column, and then, using water as an eluent, the fermentation inhibitor and the sugar are separated based on the difference in retention time, and the fraction containing the fermentation inhibitor and the fraction containing the sugar are recovered separately.

[0021] In ion exchange chromatography, when a sample is brought into contact with an ion exchange resin, the pH is usually adjusted so that the resolution of the target component relative to the impurities in the sample is maximized. Specifically, the pH is adjusted to maximize the amount of the target component adsorbed to the ion exchange resin and minimize the amount of adsorption of the impurities, the target component is adsorbed to the ion exchange resin, all the impurities are allowed to pass, and then the target component is eluted using an eluent with an increased salt concentration (ionic strength), thereby achieving separation of the target component and the impurities in the sample. Alternatively, the pH is adjusted to minimize or zero the amount of adsorption of the target component and maximize the amount of adsorption of the impurities, the impurities are adsorbed to the ion exchange resin, and all the target component is allowed to pass, thereby achieving separation of the target component and the impurities in the sample.

[0022] However, in the method of the present embodiment, the ion exchange resin is not used for its original purpose of utilizing the adsorption phenomenon, and the pH is not adjusted, and instead the fermentation inhibitor and the sugar are separated based on the difference (difference in strength) in the chemical affinity (difference in strength) between the fermentation inhibitor and the carbohydrate components (particularly glucose and fructose) in the sugar solution for the ion exchange resin. Specifically, first, the sugar solution containing the fermentation inhibitor is injected into a column filled with an ion exchange resin. Immediately after being injected into the column, the fermentation inhibitor and the carbohydrate components are not separated. Next, water is injected into the column as an eluent, and the sugar solution containing the fermentation inhibitor is pushed to the column outlet. Since water has a weaker ionic strength than the eluent used in the above-mentioned normal ion exchange chromatography, the difference in the strength of the chemical affinity of each component in the sugar solution for the ion exchange resin is maintained. Therefore, the components with a weak chemical affinity for the ion exchange resin are pushed at a speed similar to the flow rate of the column, and the components with a strong chemical affinity for the ion exchange resin are pushed slowly out of the column. This creates a difference in retention time between the fermentation inhibitor and the sugar solution containing the carbohydrate components in the column, allowing the fermentation inhibitor and the carbohydrate components to be separated. As shown in the examples described below, the fraction containing sugar may be collected after the fraction containing the fermentation inhibitor, or the fraction containing sugar may be collected before the fraction containing the fermentation inhibitor.

[0023] The basic anion exchange resin is pretreated with a solution containing a fermentation inhibitor. In other words, the anion components in the sugar solution containing the fermentation inhibitor are broken through the basic anion exchange resin. By using a basic anion exchange resin pretreated with a solution containing a fermentation inhibitor, the components in the sugar solution are not adsorbed to the ion exchange resin, and the fermentation inhibitor and the sugar components in the sugar solution can be separated from each other based on the difference (strength) of chemical affinity of the fermentation inhibitor and the sugar components in the sugar solution to the ion exchange resin. The term "breakthrough" as used here means a state in which the adsorption of any ion component to the ion exchange group of the ion exchange resin is saturated (a state in which the ion exchange group is completely replaced by any ion component), and at this time, the concentration of any ion component in the solution supplied to the column and the concentration of any ion component in the solution eluted from the column outlet are approximately the same. In the method of this embodiment, for example, the ratio (percentage) of the concentration of a specific fermentation inhibitor in a solution containing the fermentation inhibitor supplied to the column to the concentration of the specific fermentation inhibitor in the solution eluted from the column outlet is preferably 75% or more, more preferably 80% or more, even more preferably 90% or more, particularly preferably 95% or more, and most preferably 100%. As the solution containing a fermentation inhibitor to be treated with the basic anion exchange resin, there can be used those exemplified in the above <Sugar solution containing a fermentation inhibitor>, or an artificially synthesized solution obtained by adding and mixing the fermentation inhibitor and inorganic salts contained in the exemplified sugar solution containing a fermentation inhibitor to a solvent such as water. Furthermore, when the solution containing the fermentation inhibitor is a sugar liquid containing the fermentation inhibitor, the sugar liquid containing the fermentation inhibitor that is pre-treated with the basic anion exchange resin and the sugar liquid containing the fermentation inhibitor that is subjected to chromatographic separation in the recovery process may be the same as or different from each other.

[0024] In addition, the method of treating a basic anion exchange resin with a solution containing a fermentation inhibitor (hereinafter also referred to as a "breakthrough method" or "breakthrough step") can be carried out, for example, by the following procedure. First, a column is filled with a basic anion exchange resin, and a solution containing a fermentation inhibitor is fed from the column inlet. Then, as described above, after it is confirmed that the basic anion exchange resin in the column has been broken through, water is fed from the column inlet as a washing liquid to wash away the solution containing the fermentation inhibitor remaining in the column. The timing of ending the washing with water can be determined by checking the concentration of the fermentation inhibitor in the solution discharged from the column outlet. Specifically, the washing with water can be ended by confirming that the concentration of the fermentation inhibitor in the solution discharged from the column outlet is, for example, 1 w / v% or less, preferably 0.1 w / v% or less, more preferably 0 w / v%. This makes it possible to obtain a column filled with a basic anion exchange resin that has been previously treated with a solution containing a fermentation inhibitor.

[0025] In addition, when the basic anion exchange resin is new, it is preferable to further include, before the recovery step, contacting a sugar solution containing a fermentation inhibitor with a new basic anion exchange resin to adsorb the fermentation inhibitor onto the basic anion exchange resin and separating the fermentation inhibitor from the sugar (hereinafter referred to as an "adsorption / separation step"). Note that the "new basic anion exchange resin" here means a basic anion exchange resin in an unused state in which the anion exchange groups have not been replaced with other anions. By carrying out the adsorption / separation step before the recovery step, the treatment of the basic anion exchange resin with the sugar solution containing the fermentation inhibitor and the separation of the fermentation inhibitor and the sugar can be carried out simultaneously. In other words, the adsorption / separation step also corresponds to the breakthrough step. In the adsorption separation step, the sugar liquid containing the fermentation inhibitor used may be the same as or different from the sugar liquid containing the fermentation inhibitor that is subjected to chromatographic separation in the recovery step, but it is preferable that they are the same. By using the same sugar liquid, the adsorption separation step and the recovery step can be performed continuously. The method for continuously performing the adsorption separation step and the recovery step can be performed, for example, by the following procedure. First, a new basic anion exchange resin is filled in the column, and a sugar liquid containing the fermentation inhibitor is sent from the inlet of the column. As a result, the fermentation inhibitor is adsorbed to the new basic anion exchange resin, while sugar is separated and recovered because it is not adsorbed to the basic anion exchange resin. Next, as described above, it is confirmed that the basic anion exchange resin in the column has broken through. As a result, the separation of the fermentation inhibitor and the sugar by adsorption separation (adsorption separation step) is completed, and then, as described above, the separation (recovery step) is performed based on the difference (difference in strength) in chemical affinity to the basic anion exchange resin in the breakthrough state. As described above, the operation involves injecting water into the column as an eluent and forcing the sugar solution containing the fermentation inhibitors through to the column outlet, where the fermentation inhibitors and sugars are separated due to their difference in chemical affinity (strength) for the basic anion exchange resin in the breakthrough state.

[0026] The basic anion exchange resin may be a weakly basic anion exchange resin or a strongly basic anion exchange resin, but is preferably a strongly basic anion exchange resin. Examples of the weakly basic anion exchange resin include a resin having a diethylaminoethyl (DEAE) group as an ion exchanger. Examples of the strongly basic anion exchange resin include a resin having a quaternary ammonium group as an ion exchanger.

[0027] Basic anion exchange resins are - It may be of the type OH - It may be of the type Cl - It is preferable that the shape is a mold.

[0028] The resin constituting the ion exchange resin is composed of a (meth)acrylic polymer, a styrene polymer, a phenolic polymer, silica gel, etc. The resin may be crosslinked with an aromatic crosslinkable monomer such as divinyltoluene, divinylxylene, divinylnaphthalene, or divinylbenzene, or an aliphatic crosslinkable monomer such as isoprene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, or N,N'-methylenebis-acrylamide. These resins may be contained alone or in combination of two or more.

[0029] The average particle size of the ion exchange resin is, for example, 10 μm or more and 1000 μm or less, preferably 100 μm or more and 600 μm or less, more preferably 125 μm or more and 575 μm or less, even more preferably 200 μm or more and 500 μm or less, particularly preferably 200 μm or more and 400 μm or less, and most preferably 250 μm or more and 350 μm or less. By setting the average particle size of the ion exchange resin to the upper limit or less, the degree of separation between the fermentation inhibitor and the sugar is improved. On the other hand, although a high degree of separation can be achieved even if the average particle size of the ion exchange resin is smaller than 10 μm, the cost of the ion exchange resin can be reduced by setting the average particle size of the ion exchange resin to the lower limit or more. The average particle size of the ion exchange resin can be measured and calculated based on, for example, "PARTICLE SIZE DESTRIBUSION" specified in ASTM D2187-17.

[0030] The water used as the eluent may be pure water or ultrapure water.

[0031] In the recovery step, contact of the sugar solution containing the fermentation inhibitor with the ion exchange resin and separation and recovery of the fermentation inhibitor and the sugar can usually be carried out at a temperature above room temperature, specifically at a temperature above 20° C., preferably at a temperature above 25° C., more preferably at a temperature above 40° C., even more preferably at a temperature above 50° C., and particularly preferably at a temperature above 60° C. By carrying out the recovery step at a temperature above the above lower limit, the efficiency of separation of the fermentation inhibitor and the sugar can be further improved, and a higher concentration of sugar can be recovered, as shown in the examples described later. On the other hand, the upper limit of the temperature can be equal to or lower than the heat resistance temperature of the ion exchange resin, for example, 100° C., 90° C., or 80° C. In addition, when the heat resistance temperature of the ion exchange resin exceeds 100° C., the upper limit of the temperature may be higher than 100° C. as long as it is equal to or lower than the heat resistance temperature of the ion exchange resin. Methods for controlling the temperature in the recovery process include, for example, a method in which the sugar liquid containing the fermentation inhibitor to be used is preheated so that it is within a predetermined temperature range, and a method in which the temperature inside a column is controlled to be within a predetermined range using a column oven or the like.

[0032] In the recovery step, other conditions for ion exchange chromatography can be appropriately determined by those skilled in the art according to known methods.

[0033] Second Embodiment The method of the present embodiment is a method for separating a fermentation inhibitor and sugar from a sugar liquid containing the fermentation inhibitor, and recovering the sugar. The method of the present embodiment includes a removal step and a recovery step in this order. In the removal step, alkaline earth metal ions are removed from the sugar liquid containing fermentation inhibitors. In the recovery process, the sugar solution containing the fermentation inhibitor after the removal process is contacted with a monovalent cation-type acidic cation exchange resin packed in a column, and then water is used as an eluent to separate the fermentation inhibitor from the sugar based on the difference in retention time, and the fraction containing the fermentation inhibitor and the fraction containing the sugar are recovered separately.

[0034] The method according to the second embodiment of the present invention differs from the method according to the first embodiment in that it further includes a removal step and uses a monovalent cation type acidic cation exchange resin as the ion exchange resin in the recovery step, but is otherwise similar to the method according to the first embodiment.

[0035] According to the method of the second embodiment of the present invention, as shown in the examples described later, it is possible to separate fermentation inhibitors and sugars from a sugar solution containing fermentation inhibitors with good separation efficiency, and to recover sugars. Furthermore, the method of the second embodiment of the present invention does not require regeneration of the ion exchange resin, and therefore allows continuous separation.

[0036] Next, each step constituting the method according to the second embodiment of the present invention will be described in detail below, with the explanation of the steps overlapping with the method according to the first embodiment being omitted.

[0037] [Removal process] A sugar solution containing a fermentation inhibitor generally contains alkaline earth metal salts. Therefore, in the removal step, alkaline earth metal ions are removed from the sugar solution containing the fermentation inhibitor. This is because when a monovalent cation-type acidic cation exchange resin is used in the recovery step, divalent cations have a stronger adsorption force to the ion exchanger than monovalent cations, and therefore the cations that bind to the ion exchanger over time are replaced by divalent cations, i.e., alkaline earth metal ions. This changes the chemical affinity of the fermentation inhibitor and the carbohydrate components in the sugar solution to the ion exchange resin, and there is a risk that the separation ability between the fermentation inhibitor and the carbohydrate components will decrease. Therefore, by removing the alkaline earth metal ions from the sugar solution containing the fermentation inhibitor in advance, the separation ability between the fermentation inhibitor and the carbohydrate components can be maintained high. The alkaline earth metal salts referred to here are those containing alkaline earth metal ions (especially Ca 2+) Examples of the alkaline earth metal ion include magnesium ion, calcium ion, barium ion, etc. Specific examples of the alkaline earth metal salt include chlorides, hydroxides, sulfates, nitrates, etc. of the above alkaline earth metal ions.

[0038] Examples of methods for removing alkaline earth metal ions include a method in which sodium carbonate or the like is added to reduce the solubility of alkaline earth metal ions, which are then removed by precipitation. Specifically, a method in which sodium carbonate is added to a sugar solution containing a fermentation inhibitor to convert calcium ions into calcium carbonate, which is then removed by precipitation, can be mentioned. According to this method, since the solubility of calcium carbonate is low, calcium that is present in the sugar solution in the form of calcium chloride or the like is converted into calcium carbonate, and the calcium component can be precipitated.

[0039] [Recovery process] The acidic cation exchange resin used in the recovery step may be a weakly acidic cation exchange resin or a strongly acidic cation exchange resin, but is preferably a strongly acidic cation exchange resin. Examples of the weakly acidic cation exchange resin include resins having carboxylic acid groups or carboxymethyl (CM) groups as ion exchangers. Examples of the strongly acidic cation exchange resin include resins having sulfonic acid groups as ion exchangers.

[0040] Acidic cation exchange resins are monovalent cation types. The monovalent cation type is Na + Type, H + The Na + Mold is preferred.

[0041] Other conditions in the recovery step are the same as those in the method according to the first embodiment.

[0042] <Third embodiment> In the method of the present embodiment, when the sugar liquid containing the fermentation inhibitor contains sucrose as a carbohydrate component, it is preferable to further include a decomposition step before the recovery step. The decomposition step may be performed before or after the removal step. In the decomposition step, sucrose is decomposed into glucose and fructose.

[0043] The method according to the third embodiment of the present invention differs from the method according to the first or second embodiment in that it further includes a decomposition step, but is similar to the method according to the first or second embodiment in all other respects.

[0044] According to the method of the third embodiment of the present invention, fermentation inhibitors and carbohydrate components can be separated with better separation efficiency.

[0045] Next, each step constituting the method according to the third embodiment of the present invention will be described in detail below. Note that the description of the steps overlapping with the method according to the first or second embodiment will be omitted.

[0046] [Disassembly process] In the decomposition process, sucrose is decomposed into glucose and fructose. In the recovery process, sucrose tends to be difficult to separate from fermentation inhibitors, and there is a risk that sucrose will be included not only in the fraction containing sugar but also in the fraction containing fermentation inhibitors. On the other hand, glucose and fructose have chemical affinities to ion exchange resins that are significantly different from the chemical affinities of fermentation inhibitors to ion exchange resins, and therefore are easily separated from fermentation inhibitors, as shown in the examples described below. Therefore, by decomposing sucrose into glucose and fructose in advance, the fermentation inhibitors and carbohydrate components can be separated with better separation efficiency.

[0047] Methods for decomposing sucrose include known methods such as hydrolysis with an acid and decomposition with an enzyme such as invertase (also called saccharase, sucrase, or β-D-fructofuranosidase).

[0048] [Other processes] The method of the present embodiment may further include other steps, such as a detection step, as necessary. The detection step is preferably included after the recovery step. In the detection step, fermentation inhibitors and carbohydrate components in each fraction obtained in the recovery step are detected. Detection methods include methods in which the concentrations of fermentation inhibitors and carbohydrate components in each fraction eluted from the column are measured and detected using known detection means such as a detector or detection kit.

[0049] The method of this embodiment can be carried out, for example, by using an apparatus as shown below. Fig. 1 is a schematic diagram showing an apparatus according to one embodiment of the present invention, wherein the apparatus 10 shown in Fig. 1 includes a liquid chromatograph 1 and an eluent supply unit 2.

[0050] By using the apparatus 10, as shown in the examples described later, it is possible to separate the fermentation inhibitor and sugar from a sugar solution containing the fermentation inhibitor with good separation efficiency, and to recover the sugar. In addition, the apparatus of this embodiment does not require regeneration of the ion exchange resin, and therefore allows continuous separation.

[0051] [Liquid Chromatograph] Although a batch-type chromatographic separation device will be described as an example of the liquid chromatograph 1, other chromatographic separation devices may also be used. The liquid chromatograph 1 includes a liquid delivery section 3, a sample injection section 4, a separation section 5, a detection section 6, and a data processing section .

[0052] The liquid delivery section 3 is configured to deliver the eluent at a constant flow rate without pressure fluctuation, and a known pump can be appropriately selected and used according to the range of the liquid delivery flow rate. Specifically, a semi-micro LC pump can be used for a liquid delivery flow rate of about several hundred μL / min, an analytical pump can be used for a liquid delivery flow rate of about several mL / min, and a fractionation pump can be used for a liquid delivery flow rate of several tens of mL / min or more.

[0053] The sample injection unit 4 is configured to inject the sugar solution containing the fermentation inhibitor into the column, and may be either a manual injector for manual injection or an autosampler for automatic injection. The sample injection unit 4 may be equipped with a solution switching valve or the like configured to switch between the delivery of the eluent and the sugar solution containing the fermentation inhibitor.

[0054] The separation section 5 includes a column 5a and may further include a column oven 5b.

[0055] The column 5a is filled with an ion exchange resin. The ion exchange resin may be the same as that exemplified in the method for recovering sugar. The capacity of the column is not particularly limited and may be appropriately set according to the volume of the sugar liquid containing the fermentation inhibitor to be separated.

[0056] The column oven 5b is configured to keep the temperature of the column constant. The temperature in the column oven is not particularly limited, but can be kept, for example, at about 10°C to 40°C, preferably 15°C to 35°C. When sugar recovery is performed under heating, the temperature in the column oven is preferably kept at 50°C or higher, more preferably 60°C or higher. By keeping the temperature in the column oven at a temperature equal to or higher than the lower limit, the separation efficiency between fermentation inhibitors and sugar can be further improved, and sugar at a higher concentration can be recovered, as shown in the examples described later. On the other hand, the upper limit of the temperature inside the column oven can be equal to or lower than the heat resistance temperature of the ion exchange resin, for example, 100° C., 90° C., or 80° C. In addition, when the heat resistance temperature of the ion exchange resin exceeds 100° C., the upper limit of the temperature may be higher than 100° C. as long as it is equal to or lower than the heat resistance temperature of the ion exchange resin.

[0057] The detection unit 6 is configured to detect components contained in each collected fraction, and is made of a known detector generally used in liquid chromatography. Examples of known detectors include an ultraviolet-visible spectroscopic detector, a photodiode array (PDA) detector, a differential refractive index detector, a fluorescence spectroscopic detector, an electrochemical detector, an electrical conductivity detector, a mass spectrometry detector, an optical rotation detector, a circular dichroism detector, and an evaporative light scattering detector.

[0058] The data processing unit 7 is configured to calculate the content of each component in the sugar liquid from the area or height of the peak detected by the detection unit, and output the results.

[0059] [Eluent supply unit] The eluent supply unit 2 stores water 2a as an eluent and supplies it to the column. The shape and size of the eluent supply unit 2 are not particularly limited and can be appropriately selected. As the water 2a, the same water as exemplified in the method for recovering sugar can be used.

[0060] 1, the apparatus 10 may further include a fraction collector 8 configured to select and collect a fraction containing a sugar liquid (carbohydrate components). The fraction collector 8 collects a fraction 9a containing various carbohydrate components such as sucrose, glucose, fructose, etc., and discharges a fraction 9b containing fermentation inhibitors as waste liquid.

[0061] Additionally, the apparatus 10 may further comprise other components known in liquid chromatography, such as a degasser configured to remove dissolved gases in the eluent or sample.

[0062] Fig. 2 is a schematic diagram showing an apparatus according to another embodiment of the present invention. The apparatus 20 shown in Fig. 2 is different from the apparatus 10 shown in Fig. 1 in that the liquid chromatograph 1 is of a simulated moving bed type (also called a simulated moving bed method), but the other configurations are the same as those of the apparatus 10.

[0063] The simulated moving bed chromatographic separation device 1a is a device in which multiple columns C1, C2, ... C8 filled with ion exchange resin are connected in series with piping as a closed circuit. The number of columns may be four or more, and may be, for example, 4, 5, 6, 8, 10, 12, 15, 16, 18, 20, etc.

[0064] In the method of separating fermentation inhibitors and sugars using the simulated moving bed chromatographic separation apparatus 1a, first, a sugar solution containing a fermentation inhibitor is injected into the first column C1 of the simulated moving bed chromatographic separation apparatus 1a at a constant flow rate without pressure fluctuations using a pump 11 or the like, and a fraction mainly composed of fermentation inhibitors with a fast migration speed is extracted from the second column C2. Meanwhile, a fraction mainly composed of sugars with a slow migration speed is extracted from the sixth column C6 by injecting an eluent using a pump 12 or the like. Alternatively, a sugar solution containing a fermentation inhibitor is injected into the first column C1 of the simulated moving bed chromatographic separation apparatus 1a at a constant flow rate without pressure fluctuations using a pump 11 or the like, and a fraction mainly composed of sugars with a fast migration speed is extracted from the second column C2. Meanwhile, a fraction mainly composed of fermentation inhibitors with a slow migration speed is extracted from the sixth column C6 by injecting an eluent using a pump 12 or the like. In the simulated moving bed chromatographic separation device 1a, a fraction mainly containing fermentation inhibitors and a fraction mainly containing sugars are separated based on the difference in migration speed of each component.

[0065] In the simulated moving bed chromatographic separation apparatus 1a, the inlet for the sugar solution containing the fermentation inhibitor and the eluent and the outlet for the fraction mainly containing the fermentation inhibitor and the fraction mainly containing sugar are switched at regular intervals and sequentially moved to the rear stage one column at a time, so that even if the sugar solution containing the fermentation inhibitor is repeatedly circulated, each component does not spread throughout the column, and high purity fractions can be continuously extracted. In other words, by using the simulated moving bed chromatographic separation apparatus 1a, the fraction mainly containing the fermentation inhibitor and the fraction mainly containing sugar can be extracted with high purity, high concentration, and high recovery rate.

[0066] As the pumps 11 and 12, the same pumps as those exemplified for the liquid delivery section 3 of the device 10 can be used.

[0067] Additionally, the apparatus 20 may further comprise other components known in simulated moving bed chromatographic separation devices, such as a degasser configured to remove dissolved gases in the eluent or sample. EXAMPLES

[0068] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0069] [Example 1] (Na + (Recovery method of sugar solution by liquid chromatography using strong acid cation exchange resin) First, invertase (manufactured by Mitsubishi Chemical Foods Corporation, derived from yeast, titer 769 U / mL) was added to molasses with a sugar concentration of 40 w / v% at 4 μL per 1 g of molasses, and the mixture was allowed to react for 24 hours with stirring while maintaining the temperature at 50°C, thereby decomposing the sucrose in the molasses into glucose and fructose.

[0070] Next, Na + The column was packed with a type strong acid cation exchange resin (manufactured by Mitsubishi Chemical Corporation, product name "UBK530"). Next, 11 mL of molasses with a sugar concentration of 40 w / v% was supplied to the column, followed by pure water as the eluent. This test was carried out using a batch chromatographic separation device with the configuration shown below. Detailed separation conditions are as follows. Furthermore, sugars and organic acids in each fraction collected by the fraction collector were analyzed using a high performance liquid chromatograph (HPLC). Detailed analysis conditions are as follows. The results are shown in Figure 3.

[0071] (Chromatographic separation device and separation conditions) Liquid delivery unit (pump): SMP-23S (Tokyo Rikakiki) Column: 15.8mmφ×1090mm Resin filling amount: 213.6mL Molasses delivery volume: 11mL (approximately 5% by volume of resin filling volume) Flow rate: SV0.5 (the rate at which a volume of solution equal to the resin volume flows in 0.5 hours) Temperature: Normal temperature (about 25℃)

[0072] (HPLC and analysis conditions) Liquid delivery unit (pump): Prominence LC-20AD (Shimadzu Corporation) Column: (Sugar) ULTRON PS-80C, (Organic acid) TSKgel OApak-A Elution water: (sugar) ultrapure water, (organic acid) 0.75mM sulfuric acid aqueous solution Column oven: Prominence CTO-20A (Shimadzu Corporation) Temperature: (sugar) 80℃, (organic acid) 40℃ Sugar detector: Differential refractive index detector (Prominence RID-20A, Shimadzu Corporation) Organic acid detector: Electrical conductivity detector (Prominence CDD-10A, Shimadzu Corporation)

[0073] As shown in FIG. 3, fractions containing various fermentation inhibitors (lactic acid, formic acid, and acetic acid) were detected, followed by fractions containing glucose and fructose. + It was shown that various fermentation inhibitors (lactic acid, formic acid, and acetic acid) can be separated from glucose and fructose by liquid chromatography using a type-A strongly acidic cation exchange resin. In addition, by decomposing sucrose into glucose and fructose in advance, larger amounts of glucose and fructose were obtained.

[0074] [Example 2] (Cl - (Recovery method of sugar solution by liquid chromatography using strong basic anion exchange resin) First, invertase (manufactured by Mitsubishi Chemical Foods Corporation, derived from yeast, titer 769 U / mL) was added to molasses with a sugar concentration of 40 w / v% at 4 μL per 1 g of molasses, and the mixture was allowed to react for 24 hours with stirring while maintaining the temperature at 50°C, thereby decomposing the sucrose in the molasses into glucose and fructose.

[0075] The column was then filled with Cl - The column was filled with a type strong basic anion exchange resin (manufactured by Mitsubishi Chemical Corporation, product name "UMA130J", average particle size: 300 μm). Next, the invertase-treated molasses was continuously fed into the column until the concentration of various organic acids (lactic acid, formic acid and acetic acid) at the column outlet became the same as the concentration of various organic acids (lactic acid, formic acid and acetic acid) in the molasses fed into the column, causing the resin to break through. Then, a sufficient amount of pure water was fed to wash out the molasses remaining in the column. Next, 11 mL of molasses was fed into the column as a sample for separation, and then pure water was fed as an eluent. The detailed separation conditions and the analytical conditions for the obtained fractions were the same as those in Example 1. For the colored components, each fraction was photographed, the photographed images were analyzed, and the color intensity (chromaticity) was quantified. The results are shown in FIG. 4.

[0076] As shown in FIG. 4, fractions containing various fermentation inhibitors (coloring substances, lactic acid, formic acid, and acetic acid) were detected, followed by fractions containing glucose and fructose, respectively. - It was shown that various fermentation inhibitors (lactic acid, formic acid, and acetic acid) can be separated from glucose and fructose by liquid chromatography using a type-A strong basic anion exchange resin. In addition, by decomposing sucrose into glucose and fructose in advance, larger amounts of glucose and fructose were obtained.

[0077] [Comparative Example 1] (Cl - (Recovery method of sugar solution by liquid chromatography using strong basic anion exchange resin) Column Cl -The column was packed with a type 2 strongly basic anion exchange resin (manufactured by Mitsubishi Chemical Corporation, product name "UMA130J", average particle size: 300 μm). Next, 11 mL of molasses with a sugar concentration of 40 w / v% was supplied to the column, and then pure water was supplied as the eluent. The detailed separation conditions and the analytical conditions for the obtained fractions were the same as in Example 1. The results are shown in FIG. 5.

[0078] As shown in Figure 5, various fermentation inhibitors (lactic acid, formic acid, and acetic acid) were ion-exchanged, and the concentration of organic acids in the effluent was almost zero. This was due to adsorption separation, and various fermentation inhibitors (lactic acid, formic acid, and acetic acid) in molasses could be removed, but once adsorption reaches saturation, the various fermentation inhibitors (lactic acid, formic acid, and acetic acid) in molasses cannot be adsorbed and separated. Therefore, it is necessary to regenerate the saturated ion exchange resin, and it is not suitable for continuous separation.

[0079] In contrast, the methods of Examples 1 and 2 utilize the difference (strength) in chemical affinity of various fermentation inhibitors (lactic acid, formic acid, and acetic acid) and glucose and fructose to ion exchange resins for separation. Therefore, there is no need to regenerate the ion exchange resin, and continuous separation can be performed.

[0080] [Example 3] (Cl - (Recovery method of sugar solution by liquid chromatography using strong basic anion exchange resin) First, invertase (manufactured by Mitsubishi Chemical Foods Corporation, derived from yeast, titer 769 U / mL) was added to molasses with a sugar concentration of 40 w / v% at 4 μL per 1 g of molasses, and the mixture was allowed to react for 24 hours with stirring while maintaining the temperature at 50°C, thereby decomposing the sucrose in the molasses into glucose and fructose.

[0081] The column was then filled with Cl -The column was filled with a type strong basic anion exchange resin (manufactured by Mitsubishi Chemical Corporation, product name "UMA130J", average particle size: 300 μm). Next, the invertase-treated molasses was continuously supplied to the column until the concentration of various organic acids (lactic acid, formic acid and acetic acid) at the column outlet became the same as the concentration of various organic acids (lactic acid, formic acid and acetic acid) in the molasses supplied to the column, causing the resin to break through. Then, a sufficient amount of pure water was supplied to wash out the molasses remaining in the column. Next, 15 mL of molasses was supplied to the column as a sample for separation, and then pure water was supplied as an eluent. Detailed separation conditions are as shown below. Detailed analysis conditions for the obtained fractions were the same as those in Example 1. The results are shown in FIG. 6.

[0082] (Chromatographic separation device and separation conditions) Liquid delivery unit (pump): SMP-23S (Tokyo Rikakiki) Column: 20mmφ×980mm (jacketed) Resin filling amount: 307.7mL Molasses delivery volume: 15mL (approximately 5% by volume of resin filling volume) Flow rate: SV0.5 (the rate at which a volume of solution equal to the resin volume flows in 0.5 hours) Temperature: 60℃

[0083] As shown in FIG. 6, fractions containing various fermentation inhibitors (lactic acid, formic acid, and acetic acid) were detected, followed by fractions containing glucose and fructose, respectively. - It was shown that various fermentation inhibitors (lactic acid, formic acid, and acetic acid) can be separated from glucose and fructose by liquid chromatography using a type-A strong basic anion exchange resin. In addition, by decomposing sucrose into glucose and fructose in advance, larger amounts of glucose and fructose were obtained.

[0084] Furthermore, compared with the chromatogram (FIG. 4) of Example 2 carried out at room temperature (25° C.), the chromatogram (FIG. 6) of Example 3 carried out at 60° C. showed sharper peaks, particularly for glucose and fructose. This suggests that by increasing the temperature during separation and recovery, the separation efficiency of glucose and fructose from fermentation inhibitors can be improved, and the concentration of recovered sugars can be increased.

[0085] [Example 4] (Cl - (Recovery method of sugar solution by liquid chromatography using strong basic anion exchange resin) First, Cl was added to the column. - The column was filled with a type strong basic anion exchange resin (manufactured by Mitsubishi Chemical Corporation, product name "UMA130J", average particle size: 300 μm). Next, molasses with a sugar concentration of 40 w / v% was continuously supplied to the column, and the supply was continued until the concentration of various organic acids (lactic acid, formic acid and acetic acid) at the column outlet became the same as the concentration of various organic acids (lactic acid, formic acid and acetic acid) in the molasses supplied to the column, and the resin was broken through. Then, a sufficient amount of pure water was supplied to wash out the molasses remaining in the column. Next, 15 mL of bagasse saccharification liquid with a sugar concentration of 8 w / v% was supplied to the column as a sample for separation, and then pure water was supplied as an eluent. The detailed separation conditions were the same as in Example 3. The detailed analysis conditions for the obtained fractions were the same as in Example 1. The results are shown in FIG. 7.

[0086] As shown in Figure 7, in the bagasse saccharification liquid, as in the molasses, a fraction containing glucose was detected after the fractions containing various fermentation inhibitors (lactic acid, formic acid, and acetic acid). - It was shown that various fermentation inhibitors (lactic acid, formic acid and acetic acid) could be separated from glucose by liquid chromatography using a type-A strongly basic anion exchange resin.

[0087] [Example 5] (Cl - (Recovery method of sugar solution by liquid chromatography using strong basic anion exchange resin) First, Cl was added to the column. - The column was filled with a type strong basic anion exchange resin (manufactured by Mitsubishi Chemical Corporation, product name "UMA130J", average particle size: 300 μm). Next, a bagasse saccharification liquid with a sugar concentration of 10 w / v% was continuously supplied to the column until the concentration of various organic acids (formic acid and acetic acid) at the column outlet became the same as the concentration of various organic acids (formic acid and acetic acid) in the molasses supplied to the column, and the resin was broken through. Then, a sufficient amount of pure water was supplied to wash out the molasses remaining in the column. Next, 15 mL of a bagasse saccharification liquid with a sugar concentration of 10 w / v% was supplied to the column as a sample for separation, and then pure water was supplied as an eluent. The detailed separation conditions were the same as in Example 3. The detailed analysis conditions for the obtained fractions were the same as in Example 1. The results are shown in FIG. 8.

[0088] As shown in Figure 8, in the bagasse saccharification liquid, as in the molasses, fractions containing various fermentation inhibitors (formic acid and acetic acid) were detected, followed by fractions containing glucose and xylose. - It was shown that various fermentation inhibitors (formic acid and acetic acid) could be separated from glucose and xylose by liquid chromatography using a strongly basic anion exchange resin.

[0089] [Example 6] (Relationship between average particle size of ion exchange resin and separation degree) Cl with different average particle sizes - The sugar was recovered in the same manner as in Example 3, except that a type 2 strongly basic anion exchange resin was used.

[0090] Cl - The average particle size of the type strong basic anion exchange resin was measured and calculated based on "PARTICLE SIZA DESTRIBUSION" specified in ASTM D2187-17. - The average particle sizes of the type strong basic anion exchange resins were 125 μm, 250 μm, 300 μm, 350 μm, 550 μm, 570 μm, 575 μm, 650 μm, 675 μm, 740 μm, 750 μm, and 812 μm, respectively.

[0091] In addition, the degree of separation between lactic acid (selected as a representative example of a fermentation inhibitor) and glucose (selected as a representative example of sugar) by each anion exchange resin was calculated based on the formula for "PEAK RESOLUTION" specified in ASTM E682-92 (corresponding to "JIS K0124:2011 General Rules for High Performance Liquid Chromatography 3.21"). A graph showing the relationship between the average particle size of the anion exchange resin and the degree of separation is shown in Figure 9.

[0092] As shown in FIG. 9, it was revealed that in the method of this embodiment, when an anion exchange resin having an average particle size of 125 μm or more and 575 μm or less was used, the degree of separation between glucose and lactic acid was particularly high.

[0093] From the above, it is suggested that the method of the present embodiment can achieve a particularly excellent degree of separation between sugars and fermentation substances by using an anion exchange resin having an average particle size within a specific numerical range.

[0094] [Example 7] (Relationship between recovery temperature and degree of separation) Regarding the separation conditions in the chromatographic separation device, sugar was recovered using the same method as in Example 3, except that the temperatures were room temperature (approximately 20° C. or higher and 25° C. or lower), 40° C., 50° C., and 60° C. Detailed analytical conditions for the obtained fractions were the same as in Example 1. The results are shown in Figure 10 (room temperature), Figure 11 (40° C.), Figure 12 (50° C.), and Figure 13 (60° C.).

[0095] As shown in Figures 10 to 13, glucose and fructose could be separated from lactic acid and formic acid at all temperatures. In addition, the higher the temperature, the sharper the peaks of glucose and fructose tended to be. On the other hand, the lower the temperature, the more the deterioration of the anion exchange resin during continuous separation was suppressed, and continuous sugar separation tended to be possible for a longer period of time (detailed data omitted).

[0096] From the above, it was suggested that sugar can be efficiently recovered if the temperature during separation is within a specific range, taking into account the balance between the degree of separation and the durability of the resin during continuous separation. [Industrial Applicability]

[0097] According to the method of the present embodiment, it is possible to separate the fermentation inhibitor and the sugar from the sugar containing the fermentation inhibitor at low cost and with high separation efficiency, and to recover the sugar. [Explanation of symbols]

[0098] Reference Signs List: 1...liquid chromatograph, 1a...simulated moving bed chromatographic separation device, 2...eluent supply section, 2a...eluent (water), 3...liquid delivery section, 4...sample injection section, 5...separation section, 5a...column, 5b...column oven, 6...detection section, 7...data processing section, 8...fraction collector, 9a...fraction containing sugar (carbohydrate component), 9b...fraction containing fermentation inhibitor, 10, 20...apparatus, 11, 12...pump.

Claims

1. A method for separating a fermentation inhibitor and sugar from a sugar liquid containing a fermentation inhibitor, and recovering the sugar, comprising the steps of: the sugar solution containing the fermentation inhibitor is contacted with an ion exchange resin packed in a column, and then the fermentation inhibitor and the sugar are separated based on the difference in retention time using water as an eluent, and a fraction containing the fermentation inhibitor and a fraction containing the sugar are separately recovered; The fermentation inhibitor is an organic acid, a coloring component, or a by-product of saccharification; the organic acid is formic acid, acetic acid or lactic acid; The coloring component is melanoidin, polyphenol, or caramel, the saccharification by-product is furfural or 5-hydroxymethylfurfural; the sugar is sucrose, glucose, fructose, xylose, or mannose; The ion exchange resin is a strongly basic anion exchange resin or a strongly acidic cation exchange resin, The method, wherein the ion exchange resin is broken through by a sugar liquid containing a fermentation inhibitor.

2. The method according to claim 1, wherein the average particle size of the ion exchange resin is 100 μm or more and 600 μm or less.

3. 3. The method according to claim 1 or 2, further comprising contacting the sugar liquid containing the fermentation inhibitor with the ion exchange resin when the sugar liquid containing the fermentation inhibitor breaks through, thereby adsorbing the fermentation inhibitor onto the ion exchange resin and separating the fermentation inhibitor from the sugar.

4. The method according to any one of claims 1 to 3, wherein in the recovery, a fraction containing the sugar is recovered after a fraction containing the fermentation inhibitor.

5. The method according to any one of claims 1 to 4, wherein the sugar liquid containing a fermentation inhibitor contains glucose or fructose.

6. The method according to any one of claims 1 to 4, wherein the sugar liquid containing the fermentation inhibitor contains sucrose.

7. 7. The method of claim 6, further comprising degrading said sucrose into glucose and fructose prior to said recovering.

8. The method according to any one of claims 1 to 7, wherein the recovery is carried out at a temperature of 25°C or higher.

9. The method according to any one of claims 1 to 8, wherein the fermentation inhibitor comprises at least one selected from the group consisting of organic acids and coloring components.

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