JP2012125174A - Method for producing glucose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing glucose having cellulose as a raw material and high usability, and capable of being put into practical use in an industrial level.SOLUTION: The method for producing the glucose by hydrolyzing the cellulose includes steps of: supplying an aqueous solution of a hydrolytic agent to the cellulose; hydrolyzing the cellulose; and recovering the glucose from a hydrolysate of the cellulose.

Description

  The present invention relates to a method for producing glucose by hydrolyzing cellulose.

Plants are rich in cellulose, which is said to be the most abundant biomass on earth. Therefore, various methods for effectively using cellulose have been studied, and various techniques for glucose production by hydrolysis are disclosed. Glucose is also a raw material for producing ethanol by fermentation.
The cellulose hydrolysis methods disclosed so far can be broadly classified into two types: biological methods and chemical methods.

  Biological techniques are methods that use cellulase, which is a hydrolase, and high-activity cellulase and cellulase-producing bacteria (see Non-Patent Document 1) have been actively developed so far. Enzymes have substrate specificity and have the advantage that no by-products are produced due to excessive decomposition of glucose such as furfural and 5-hydroxymethyl-2-furfural (HMF). In addition, unlike acid saccharification, it is not necessary to remove a product that becomes an inhibitor of yeast fermentation. For this reason, it is considered that the use of an enzyme is suitable in the saccharification reaction of lignocellulose.

  On the other hand, as a chemical method, there is a so-called acid saccharification method, and various studies have been made for a long time. For example, a concentrated hydrochloric acid method (Prodor method) is known, but as a practical method at present, The concentrated sulfuric acid saccharification method (Arkenol method) of Arkenol is known (see Patent Document 1). In recent years, a method using a solid acid catalyst (see Non-Patent Document 2), a method using a Lewis acid (metal chloride) (see Non-Patent Document 3), a method using a lanthanoid ion, a supercritical fluid The method to use (refer nonpatent literature 4) etc. are disclosed.

Japanese Patent Laid-Open No. 11-506934

Yuko, I. et al. Hiroyuki, H .; Y, P .; E. Naoyuki, O .; Biotechnol Prog. 2007, 23, 333-338. Masaaki, K .; Daizo, Y .; Michikazu, H .; Satoshi, S .; Kiyotaka, N .; Hideki, K .; Shigenobu, H .; Ibaraki; Jpn Langmuir 2009, 25, 5068-5075. S, A. A. C, E .; C. Bioresource. Technol. 2009, 100, 5301-5304. Asian Biomass Handbook, Biomass Utilization Guide, Japan Institute of Energy

However, the biological method has a problem that it takes time for the enzyme reaction, is very expensive, and is difficult to put into practical use at an industrial level.
Further, among the chemical methods, the acid saccharification method has a problem that the amount of acid used is enormous and the recovery thereof is difficult. Concentrated sulfuric acid, in particular, is difficult to reuse, and thus produces a huge amount of industrial waste. Furthermore, since it is difficult to recover the acid, there is a problem in that the use of the obtained glucose is greatly limited, such that it cannot be used for subsequent ethanol production by yeast fermentation. In addition, the method using a solid acid catalyst, the method using a Lewis acid, the method using a lanthanoid ion, and the method using a supercritical fluid all require expensive or harmful compounds, or are reactive. There is a problem that it is difficult to put it to practical use at an industrial level, for example, it is extremely low, severe reaction conditions are required, and special equipment is required. In particular, the method using a supercritical fluid is very disadvantageous in terms of energy cost.
Thus, conventionally, as a method for producing glucose using cellulose as a raw material, there is no process that is simple and low-cost, highly versatile, such as high safety, and can be put to practical use at an industrial level. Was the actual situation.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the manufacturing method of glucose which uses cellulose as a raw material, has high versatility, and can be put into practical use on an industrial level.

To solve the above problem,
The present invention is a method for producing glucose by hydrolyzing cellulose, the step of supplying an aqueous solution of a hydrolyzing agent to cellulose, the step of hydrolyzing cellulose, and the step of recovering glucose from the hydrolyzate of cellulose. A method for producing glucose is provided.
In the glucose production method of the present invention, the hydrolyzing agent is preferably iron (III) chloride.
In the glucose production method of the present invention, the cellulose is preferably crystalline cellulose.
In the glucose production method of the present invention, in the step of hydrolyzing the cellulose, it is preferable to hydrolyze the cellulose while heating at 190 to 240 ° C.
In the method for producing glucose of the present invention, in the step of supplying an aqueous solution of a hydrolyzing agent to the cellulose, an aqueous solution of the hydrolyzing agent is supplied from the upstream side of the column containing the cellulose, and the hydrolyzate of the cellulose In the step of recovering glucose from the column, it is preferable to provide a filter having an average pore diameter of 4 μm or less downstream of the cellulose in the column and recover glucose from the downstream side of the filter.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of glucose which uses cellulose as a raw material, has high versatility, and can be put into practical use at an industrial level can be provided.

It is a schematic block diagram which illustrates the manufacturing apparatus of glucose suitable for application to this invention. It is a figure which shows the analysis result by HPLC of glucose in Experimental example 1. FIG.

  The glucose production method of the present invention is a method for producing glucose by hydrolyzing cellulose, comprising a step of supplying an aqueous solution of a hydrolyzing agent to cellulose, a step of hydrolyzing cellulose, and a hydrolyzate of cellulose. It has the process of collect | recovering glucose, It is characterized by the above-mentioned.

The glucose production method of the present invention is preferably, for example, a so-called flow type (continuous type) that continuously supplies an aqueous solution of a hydrolyzing agent for hydrolyzing cellulose and collects glucose. By doing in this way, the excessive decomposition which the target glucose is further decomposed | degraded is suppressed, and glucose can be obtained efficiently.
When cellulose is hydrolyzed, in addition to the target monosaccharide glucose, fructose; cellooligosaccharides such as cellobiose, cellotriose, cellotetraose, cellopentaose; furfural, 5-hydroxymethyl -2-furfural (HMF) and the like are generated. In the present invention, by using the above-described continuous system, glucose is easily generated by the aqueous solution of the hydrolyzing agent, and by-products such as furfural and HMF are remarkably suppressed, and glucose is efficiently obtained.

  In the present invention, “continuously supplying the aqueous solution of the hydrolyzing agent to the cellulose” does not necessarily mean that the aqueous solution of the hydrolyzing agent is continuously supplied to the cellulose. For example, an aqueous solution of a hydrolyzing agent may be intermittently supplied to cellulose. In this case, the supply stop time is preferably within 30 seconds.

In the present invention, first, an aqueous solution of a hydrolyzing agent is supplied to cellulose to hydrolyze the cellulose.
The cellulose may be composed only of cellulose, or may be a complex in which other components such as hemicellulose and lignin are bound.

  The cellulose source used as a raw material is not particularly limited, and only cellulose may be used, a mixture of cellulose and other components may be used, or a plant containing cellulose or a processed product thereof may be used. good. Here, the plant processed product refers to, for example, a plant obtained by performing one or more operations selected from the group consisting of crushing, grinding, cutting, drying, dissolution, and component extraction on plants. .

  Preferred examples of the cellulose include crystalline cellulose, wheat straw, rice straw and the like. In particular, crystalline cellulose is known as a raw material that is hardly decomposed during hydrolysis, but in the present invention, glucose can be used as a suitable raw material from which glucose can be obtained efficiently.

In the present invention, “crystalline cellulose” refers to those having a “crystallinity” of 70% or more determined by analysis by X-ray diffraction (XRD). “Crystallinity” is defined by the ratio of crystalline region to amorphous (amorphous) region in cellulose and can be calculated by the following formula (1). “High crystallinity” means that there are many crystalline regions. To do.
Crystallinity [%] = (I ₀₀₂ −I _am ) / I ₀₀₂ × 100 (1)
[Wherein I ₀₀₂ is the X-ray diffraction intensity at 2θ = 22.8 °, and I _am is the X-ray diffraction intensity at 2θ = 18 °. ]

  Crystalline cellulose can reduce crystallinity by performing pretreatment with alkali or pretreatment for removing hemicellulose or lignin. By reducing the crystallinity, the hydrolysis of cellulose may proceed more easily. In the pretreatment with alkali, for example, an aqueous solution of alkali such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate or the like can be used.

  The cellulose is preferably granular, and preferably has a particle size of about 200 Mesh (mesh). By using such cellulose, hydrolysis of cellulose proceeds more easily.

  The said cellulose may be used individually by 1 type, and may use 2 or more types together. When using 2 or more types together, the combination can be arbitrarily selected.

Examples of the hydrolyzing agent include metal hydrochlorides, sulfates, carbonates, trifluoromethanesulfonates, etc., and examples of the metals include alkali metals; alkaline earth metals; and other metals such as transition metals. it can. Of these, iron (III) chloride (hereinafter abbreviated as FeCl ₃ ) is particularly preferable as the hydrolyzing agent.
FeCl ₃ may be either an anhydride or hexahydrate, or may be prepared using iron powder and hydrochloric acid.

  The concentration of the hydrolyzing agent in the aqueous solution may be appropriately adjusted, but is preferably 0.5 to 120 mM, more preferably 0.5 to 80 mM, and particularly preferably 5 to 20 mM. . By setting it to the lower limit value or more, it can be hydrolyzed more rapidly, and by setting it to the upper limit value or less, glucose can be taken out more easily. In the present specification, the unit “M” represents “mol / l”.

  The said hydrolyzing agent may be used individually by 1 type, and may use 2 or more types together. When using 2 or more types together, the combination and ratio can be selected arbitrarily.

  Hydrolysis is preferably performed while heating, and in this way, hydrolysis can be performed more rapidly. The temperature during heating is preferably 120 ° C. or higher, more preferably 150 to 240 ° C., and particularly preferably 190 to 240 ° C. By setting it to the upper limit value or less, the excessive decomposition of glucose can be further suppressed.

  The reaction time for hydrolysis may be adjusted as appropriate according to the reaction temperature, and is not particularly limited. For example, in the case of heating as described above, it is preferably 0.2 to 10 hours, and more preferably 0.5 to 4 hours.

  The supply amount (flow rate) of the aqueous solution of the hydrolyzing agent may be appropriately adjusted according to the concentration of the aqueous solution, the amount of cellulose, and the form of the glucose production apparatus.

  The aqueous solution of the hydrolyzing agent may contain other components other than the hydrolyzing agent as long as the effects of the present invention are not hindered.

  Cellulose may be newly added during the hydrolysis reaction. By doing in this way, without stopping a hydrolysis reaction, it can carry out continuously for a long time, can manufacture glucose continuously, and can improve the manufacturing efficiency of glucose significantly. Specific examples of the method for adding cellulose include, but are not limited to, a method applied by a method using a percolator reactor in a conventional Scholar method.

  For example, cellulose is easily hydrolyzed in a state where it is placed in a column, whereby cellulose as a raw material and glucose as a target product can be easily separated, so that glucose can be recovered more easily. That is, in the present invention, it is preferable to supply the aqueous solution of the hydrolyzing agent from the upstream side of the column containing cellulose and collect glucose from the column or from the downstream side of the column.

In this invention, after hydrolyzing a cellulose, glucose is collect | recovered from the hydrolyzate.
For example, when the column is used, it is preferable to provide a filter that does not allow a hydrolyzate having a large molecular size to pass downstream from the cellulose in the column and collect glucose from the downstream side of the filter.

  The filter is preferably one that can filter out oligosaccharides having higher solubility in water than heptasaccharides (oligosaccharides with seven monosaccharides bonded), and the average pore diameter is preferably 4 μm or less, It is more preferable that it is 1-3 micrometers. By setting it to 4 μm or less, the insoluble matter filtering effect is enhanced, and the yield of glucose is further improved. Furthermore, a higher effect of suppressing liquid feeding failure due to clogging of insoluble matters can be obtained. Moreover, liquid feeding can be performed more easily by setting it as 1 micrometer or more.

FIG. 1 illustrates a manufacturing apparatus suitable for the present invention.
The production apparatus 1 shown here includes a column 11 for containing cellulose (not shown), a heater 12 for adjusting the temperature of the column 11, and a pump 13 for supplying an aqueous solution 19 of a hydrolyzing agent to the column 11. And the pump 13 are connected by a pipe 14. Further, the pump 13 is connected to a liquid raw material reservoir 15 for storing an aqueous solution 19 of a supply hydrolyzing agent and a pipe 14. The column 11 is connected by a back pressure regulator 17 and a pipe 14 for adjusting the pressure of the reaction solution 9 sent from here, and a part of the pipe 14 between the column 11 and the back pressure regulator 17 is It is incorporated in a cooling unit 16 for cooling the delivered reaction solution 9. The reaction liquid 9 that has passed through the back pressure regulator 17 is stored in the product storage unit 18.

As the heater 12, for example, a heater having a temperature adjustment part that directly contacts the column 11 and adjusts the temperature is suitable.
The cooling unit 16 may have, for example, a temperature adjustment part that directly adjusts the temperature by directly contacting the pipe 14, or a temperature adjustment part that adjusts the temperature of a medium such as gas or liquid, and the medium is connected to the pipe 14. It may be in contact with.

  The column 11 includes first filters 111 in the vicinity of the upstream inlet 11a and in the vicinity of the downstream outlet 11b, respectively, through which an aqueous solution 19 of the hydrolyzing agent can pass, and cellulose in the column 11 Does not leak to the outside. And in the vicinity of the outlet 11b on the downstream side of the column 11, a second filter 112 is provided further downstream than the first filter 111, and among the decomposition products generated by hydrolysis of cellulose, Only molecules having a molecular size smaller than a predetermined size dissolved in the reaction solution are sent from the column 11 to the downstream side. The second filter 112 filters the oligosaccharide having low solubility in water as described above.

  Among the degradation products of cellulose, monosaccharide to hexasaccharide (oligosaccharide having 6 monosaccharides bonded) is usually dissolved in the reaction solution. Therefore, these saccharides pass through without being separated by the second filter 112 and are sent downstream. Among these, glucose is most likely to pass through the second filter 112. On the other hand, oligosaccharides higher than heptasaccharide are difficult to dissolve in the reaction solution and are filtered out by the second filter 112 as insoluble matter and are not sent out from the column 11. And it is sent only after it is decomposed into saccharides of hexasaccharide or less.

  The pore diameter of the first filter 111 may be a size that can prevent leakage of cellulose, and is preferably increased within a range that does not hinder liquid feeding.

  What is necessary is just to adjust the size of the column 11 suitably according to the quantity of the said cellulose with which it uses for a decomposition | disassembly. For example, when the amount of the cellulose is about 10 g or less, the inner diameter of the cellulose accommodating portion is preferably 2 to 10 cm and the length is 5 to 20 cm.

  For example, when the flow rate of the aqueous solution 19 of the hydrolyzing agent is 10 ml / min or less, the diameter of the pipe 14 is preferably 0.1 to 2 mm, and more preferably 0.6 to 1.4 mm. preferable. By setting it as such a range, the still higher effect which can supply the said aqueous solution 19 easily can be acquired, suppressing clogging.

It is preferable that each component of the manufacturing apparatus 1 is made of a material having acid resistance at a site where the aqueous solution of the hydrolyzing agent or the reaction solution contacts. For example, considering the case of using FeCl ₃ that is particularly suitable as a hydrolyzing agent, a 10 mM FeCl ₃ aqueous solution has a pH of about 2 and exhibits acidity. Examples of materials having acid resistance against such acidity include glass; alloys such as stainless steel; resins such as polyether ether ketone resin (PEEK) and polytetrafluoroethylene. It is not limited to.
Furthermore, the column 11 is preferably made of a material having heat resistance with respect to the heating temperature during hydrolysis.

The manufacturing apparatus 1 may be partially changed, added, or deleted within a range that does not hinder the effects of the present invention.
For example, in the column 11, as long as the second filter 112 is provided, the first filter 111 may not be provided near the downstream outlet 11b. Further, the first filter 111 may not be provided in the vicinity of the inlet 11a on the upstream side.
Further, as described above, for example, a cellulose inlet may be separately provided in the column 11 so that cellulose can be newly added during the hydrolysis reaction. Further, a separate outlet for the residue may be provided in the column 11 so that the cellulose residue after hydrolysis can be removed. The input port may also serve as the extraction port.

By using the production apparatus 1, glucose can be produced as follows.
That is, the aqueous solution 19 of the hydrolyzing agent in the liquid raw material reservoir 15 is continuously supplied into the column 11 by the pump 13. At this time, the degree of hydrolysis can be adjusted by adjusting the temperature of the column 11 with the heater 12. The hydrolysis of cellulose proceeds in the column 11 by the aqueous solution 19 of the supplied hydrolyzing agent. The glucose produced at this time is sent out together with the reaction solution 9 from the outlet 11b on the downstream side of the column 11, and this reaction solution 9 is cooled by the cooling unit 16 to stop hydrolysis, and then passes through the back pressure regulator 17. Then, it is stored and recovered in the product storage unit 18.

  In the column 11, oligosaccharides are generated along with the decomposition of cellulose. However, since the sugar stays in the column 11 until the saccharide is approximately hexasaccharide or less, it is sufficiently decomposed into glucose. In addition, since the produced glucose is most likely to pass through the second filter 112 among the decomposed products, it is quickly sent out from the column 11, and the reaction liquid 9 is further cooled to stop the hydrolysis. Decomposition is suppressed. Thus, since the production efficiency of glucose is high and the effect of suppressing excessive decomposition is high, glucose can be obtained in a high yield under conditions milder than the conventional production method.

  When the production apparatus 1 is used to decompose, for example, 10 g or less, preferably 1 to 10 g of cellulose using a column 11 having an inner diameter of 2 to 10 cm and a length of 5 to 20 cm. The supply amount (flow rate) of the aqueous solution of the hydrolyzing agent is preferably 10 ml / min or less, more preferably 0.4 to 10 ml / min, and particularly preferably 0.7 to 6 ml / min. preferable. By setting it to the lower limit or higher, cellulose can be decomposed more efficiently, and by setting it to the upper limit or lower, glucose can be more selectively sent out from the column 11. In particular, the above conditions are suitable when hydrolysis is performed by continuously supplying an aqueous solution of a hydrolyzing agent to cellulose.

The recovered reaction liquid often contains other decomposition products, FeCl _{3 and the} like in addition to the target glucose. Therefore, in such a case, the recovered reaction solution is subjected to one or more known purification operations such as extraction, concentration, activated carbon treatment, desalting treatment, gel filtration, column chromatography, and further, concentration, freeze drying, etc. It is preferable to take out glucose by performing.

The obtained glucose may be a known technique such as high performance liquid chromatography (HPLC), nuclear magnetic resonance ( ¹ H-NMR, ¹³ C-NMR, etc.), mass spectrometry (MS) or the like alone or in combination of two or more. It can be identified by applying in combination.

According to the present invention, cellulose can be sufficiently hydrolyzed to glucose, and further cellulose can be hydrolyzed while collecting the produced glucose. Therefore, the amount of glucose produced is improved, and the excessive decomposition of glucose is suppressed. Glucose is obtained in a yield. Furthermore, by using FeCl ₃ as a hydrolyzing agent that hydrolyzes cellulose with high efficiency, glucose can be obtained at a higher yield. And the yield of glucose can be further improved by adjusting the reaction temperature, the supply amount of the aqueous solution of the hydrolyzing agent, the average pore size of the second filter, and the like. In addition, all the raw materials used are excellent in safety and availability, the reaction conditions are mild, and no special production conditions are required. Thus, glucose can be produced at a low cost with a simple process. As described above, the present invention has high versatility and can be easily put to practical use at an industrial level.
On the other hand, in the conventional manufacturing method, as described above, the versatility is low and it is difficult to put it to practical use at an industrial level. In particular, in the batch method, since cellulose as a raw material and glucose as a product always coexist in the reaction solution, excessive hydrolysis of glucose is unavoidable when trying to fully hydrolyze cellulose. When it is going to suppress, hydrolysis of a cellulose will become inadequate and as a result, glucose cannot be obtained with a high yield.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples.
The “glucose yield (%)” shown below is all isolated yield. In the following experimental examples, a hydrolysis reaction is carried out by continuously supplying an aqueous metal salt solution such as an FeCl ₃ aqueous solution or an acid aqueous solution such as hydrochloric acid to cellulose.

[Experimental Example 1]
Using the production apparatus 1 shown in FIG. 1, glucose was produced by the following procedure. As the column 11, a preparative column (manufactured by GL Sciences, A-type preparative column (inner diameter 2 cm, length 5 cm), Cat. No. 6010-15020) is used, and the average pore diameter of the second filter 112 is The thickness was 2 μm. In the preparative column, the first filter 111 is not provided in the vicinity of the upstream inlet 11a or the downstream outlet 11b. The pipe 14 is made of stainless steel and has a diameter of 1 mm. As the heater 12, an oven for gas chromatography (manufactured by SHIMADZU, GC-14A), as the cooling unit 16, a water bath, as the back pressure regulator 17, JASCO 880-81 (manufactured by JASCO Corporation), Each was used.

5.00 g of crystalline cellulose (Aldrich, cellulose, microcrystalline, powder Cat. No. 435236-250G) (particle size 200 Mesh) having a crystallinity of 85% (particle size 200 Mesh) was placed in the column 11, and the flow rate was 2 ml / ml at room temperature. The ultrapure water was allowed to flow for 30 minutes to remove cellulose particles having a particle size of 2 μm or less, and the crystalline cellulose was suspended.
Then, as shown in Table 1, the column 11 is heated by setting the temperature of the heater 12 to 220 ° C. (reaction temperature), and the FeCl ₃ aqueous solution 19 having a concentration of 10 mM is flowed for 2 hours (reaction time) at a flow rate of 2 ml / min. By flowing through the column 11, the hydrolysis reaction of crystalline cellulose was performed, and the sent reaction liquid 9 was recovered.
Next, the recovered reaction solution 9 was subjected to activated carbon treatment and desalting treatment, and the solvent was distilled off under reduced pressure, followed by lyophilization to obtain 4.53 g (91% yield) of the solubilized component. This solubilized portion was subjected to ion exchange chromatography (strongly acidic cation exchange resin: Dowex Finemesh 50WX2 (100-200 Mesh) Ca ²⁺ type)), followed by separation and purification. Finally, 3.74 g of glucose ( Yield 75%).

The resulting glucose was identified by HPLC analysis. The analysis conditions are as follows. Moreover, the obtained analysis result (HPLC chart) is shown in FIG. As is clear from FIG. 2, high-purity glucose was obtained.
(HPLC analysis conditions)
Column: Shodex SB-G + SB-802HQ + SB-802.5HQ
Flow rate: 0.7 ml / min Temperature: 70 ° C
Mobile phase: 0.1 M NaNO ₃ aqueous solution

[Experiment 2]
As shown in Table 1, hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that the concentration of the FeCl ₃ aqueous solution was changed to 10 mM instead of 10 mM. As a result, 1.19 g (yield 24%) of the solubilized component and 0.73 g (yield 15%) of glucose were obtained.

[Experiment 3]
As shown in Table 1, a hydrolysis reaction was performed in the same manner as in Experimental Example 1 except that the concentration of the FeCl ₃ aqueous solution was changed to 100 mM instead of 10 mM, and 1.57 g (yield 31%) of a solubilized component was obtained. However, this solubilized component was caramelized.

[Experimental Example 4]
As shown in Table 1, hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that the reaction temperature was changed to 200 ° C. instead of 220 ° C. As a result, 2.55 g (51% yield) of the solubilized component and 1.68 g (34% yield) of glucose were obtained.

[Experimental Example 5]
As shown in Table 1, the hydrolysis reaction was carried out in the same manner as in Experimental Example 1 except that the reaction temperature was changed to 180 ° C. instead of 220 ° C. As a result, 0.43 g (yield 9%) of a solubilized component was obtained, but glucose could only be confirmed by HPLC, and only a trace amount was obtained.

[Experimental Example 6]
As shown in Table 1, the hydrolysis reaction was attempted in the same manner as in Experimental Example 1 except that the flow rate of the FeCl ₃ aqueous solution was changed to 1 ml / min instead of 2 ml / min. The hydrolysis reaction could not be performed.

[Experimental Example 7]
As shown in Table 1, hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that the flow rate of the FeCl ₃ aqueous solution was changed to 3 ml / min instead of 2 ml / min. As a result, 2.28 g (yield 45%) and 1.83 g (37% yield) of glucose were obtained.

[Experimental Example 8]
As shown in Table 1, the hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that the flow rate of the FeCl ₃ aqueous solution was changed to 4 ml / min instead of 2 ml / min. As a result, 2.55 g (51% yield) of the solubilized component and 1.68 g (34% yield) of glucose were obtained.

High-purity glucose was obtained by the production method of the present invention (particularly Experimental Examples 1-2, 4, 7, 8).
Moreover, as shown in Experimental Example 1, the yield of glucose could be improved to 75% by adjusting the hydrolysis conditions. This is more than 60% reported in the concentrated hydrochloric acid method (Prodor method) known as a conventional method, and a high yield comparable to 80% reported in the concentrated sulfuric acid method (Arkenol method). It is.
The production method of the present invention has higher versatility than these conventional methods, and can be easily put into practical use at an industrial level.

[Experimental Example 9]
5.00 g of crystalline cellulose having a crystallinity of 85% (manufactured by Aldrich, cellulose, microcrystalline, powder Cat. No. 435236-250G) (particle size of about 200 Mesh) is placed in the column 11, and the flow rate is 5 ml at room temperature. Ultra pure water was allowed to flow for 30 minutes per minute to remove cellulose particles having a particle size of 2 μm or less and to suspend crystalline cellulose.
Next, as shown in Table 2, the column 12 is heated by setting the temperature of the heater 12 to 220 ° C. (reaction temperature), and pH 2 hydrochloric acid is allowed to flow through the column 11 for 2 hours (reaction time) at a flow rate of 2 ml / min. Then, the hydrolysis reaction of crystalline cellulose was performed, and the delivered reaction solution was recovered.
Subsequently, the recovered reaction solution was subjected to activated carbon treatment and desalting treatment, and the solvent was distilled off under reduced pressure, followed by lyophilization to obtain 3.55 g (yield 71%) of a solubilized component. This solubilized portion was subjected to ion exchange chromatography (strongly acidic cation exchange resin: Dowex Finemesh 50WX2 (100-200 mesh) Ca ²⁺ type)), followed by separation and purification. Finally, 2.72 g of glucose ( Yield 54%).

[Experimental Example 10]
As shown in Table 2, hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 9 except that a pH 2 sulfuric acid aqueous solution was used instead of pH 2 hydrochloric acid. As a result, 3.33 g (yield 67%) of the solubilized component and 2.30 g (yield 46%) of glucose were obtained.

[Experimental Example 11]
As shown in Table 2, hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 9, except that a pH 2 formic acid aqueous solution was used instead of pH 2 hydrochloric acid. As a result, 1.94 g (yield 39%) of the solubilized component and 1.22 g (yield 24%) of glucose were obtained.

Experimental Examples 9 to 11 correspond to the conventional acid saccharification method, but the separation and purification of glucose is particularly complicated and the recovery of the acid is difficult compared to the case of using an FeCl ₃ aqueous solution.

[Experimental example 12]
3.00 g of straw (powder) was placed in the column 11, and ultrapure water was allowed to flow at room temperature at a flow rate of 5 ml / min for 30 minutes to remove substances having a particle size of 2 μm or less, and the straw was suspended. .
Next, as shown in Table 3, the temperature of the heater 12 was set to 220 ° C. (reaction temperature), the column 11 was heated, and the FeCl ₃ aqueous solution 19 having a concentration of 10 mM at a flow rate of 2 ml / min was added for 2 hours (reaction time). By flowing it through the column 11, the straw was subjected to a hydrolysis reaction, and the sent reaction liquid 9 was recovered.
Next, the recovered reaction solution 9 was subjected to activated carbon treatment and desalting treatment, and the solvent was distilled off under reduced pressure, followed by lyophilization to obtain 1.19 g (yield 40%) of a solubilized component. This solubilized portion was subjected to ion exchange chromatography (strongly acidic cation exchange resin: Dowex Finemesh 50WX2 (100-200 Mesh) Ca ²⁺ type)), followed by separation and purification. Finally, 0.64 g of glucose ( Yield 21%).

[Experimental Example 13]
As shown in Table 3, hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 12 except that rice straw was used instead of wheat straw. As a result, 1.94 g (yield 39%) of the solubilized component and 1.22 g (yield 24%) of glucose were obtained.

  As apparent from Experimental Examples 12 to 13, glucose was obtained in a good yield even when cellulose used in the conventional production method was used as a raw material. The methods of Experimental Examples 12 to 13 are also highly versatile and easy to put into practical use at an industrial level.

[Experimental Example 14]
As shown in Table 4, in the same manner as in Experimental Example 1 except that a 10 mM iron (III) (Fe ₂ (SO ₄ ) ₃ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution, hydrolysis reaction and Glucose separation and purification were performed. As a result, the solubilized component was obtained in a yield of 56% and glucose was obtained in a yield of 29%.

[Experimental Example 15]
As shown in Table 4, hydrolysis reaction and glucose separation were performed in the same manner as in Experimental Example 1 except that a 10 mM aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. And purification was performed. As a result, a solubilized component was obtained with a yield of 40% and glucose was obtained with a yield of 19%.

[Experimental Example 16]
As shown in Table 4, the hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1, except that a 10 mM aluminum chloride (AlCl ₃ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. . As a result, the solubilized component was obtained with a yield of 49% and glucose with a yield of 17%.

[Experimental Example 17]
As shown in Table 4, hydrolysis reaction and separation and purification of glucose were performed in the same manner as in Experimental Example 1 except that a 10 mM iron (II) chloride (FeCl ₂ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. Went. As a result, the solubilized component was obtained in a yield of 36% and glucose was obtained in a yield of 15%.

[Experiment 18]
As shown in Table 4, in the same manner as in Experimental Example 1 except that a 10 mM ytterbium (III) triflate (Yb (OTf) ₃ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution, hydrolysis reaction and glucose Separation and purification were performed. As a result, the solubilized component was obtained in a yield of 28% and glucose was obtained in a yield of 9%. Here, “triflate (OTf)” refers to trifluoromethanesulfonic acid.

[Experimental Example 19]
As shown in Table 4, the hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that a 10 mM lanthanum chloride (LaCl ₃ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. . As a result, the solubilized component was obtained in a yield of 16% and glucose was obtained in a yield of 8%.

[Experiment 20]
As shown in Table 4, hydrolysis reaction and glucose separation were performed in the same manner as in Experimental Example 1 except that a 10 mM lanthanum carbonate (La ₂ (CO ₃ ) ₃ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. And purification was performed. As a result, a solubilized component was obtained at a yield of 11% and glucose was obtained at a yield of 4%.

[Experimental example 21]
As shown in Table 4, the hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that a 10 mM manganese chloride (MnCl ₂ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. . As a result, a solubilized component was obtained at a yield of 10% and glucose was obtained at a yield of 4%.

[Experimental example 22]
As shown in Table 4, the hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1, except that a 10 mM lithium chloride (LiCl) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. As a result, the yield of the solubilized component was 4%, and only a trace amount of glucose could be obtained only by confirming the presence by HPLC.

[Experimental example 23]
As shown in Table 4, the hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that a 10 mM sodium chloride (NaCl) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. As a result, the yield of the solubilized component was 4%, and glucose could only be confirmed by HPLC, and only a trace amount was obtained.

[Experimental Example 24]
As shown in Table 4, the hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that a 10 mM potassium chloride (KCl) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. As a result, the yield of the solubilized component was 3%, and glucose could only be confirmed by HPLC, and only a trace amount was obtained.

[Experiment 25]
As shown in Table 4, the hydrolysis reaction and the separation and purification of glucose were performed in the same manner as in Experimental Example 1 except that a 10 mM magnesium sulfate (MgSO ₄ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. . As a result, the yield of the solubilized component was 3%, and glucose could only be confirmed by HPLC, and only a trace amount was obtained.

[Experiment 26]
As shown in Table 4, the hydrolysis reaction and the separation and purification of glucose were performed in the same manner as in Experimental Example 1 except that a 10 mM lithium carbonate (Li ₂ CO ₃ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. went. As a result, the yield of the solubilized component was 2%, and glucose could only be confirmed by HPLC, and only a trace amount was obtained.

[Experiment 27]
As shown in Table 4, hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that a 10 mM iron (II) sulfate (FeSO ₄ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. Went. As a result, the yield of the solubilized component was 2%, and glucose could only be confirmed by HPLC, and only a trace amount was obtained.

[Experiment 28]
As shown in Table 4, the hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1, except that a 10 mM calcium chloride (CaCl ₂ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution. . As a result, the yield of the solubilized component was 2%, and glucose could only be confirmed by HPLC, and only a trace amount was obtained.

[Experimental example 29]
As shown in Table 4, the hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1 except that ultrapure water was used instead of the 10 mM FeCl ₃ aqueous solution. As a result, the yield of the solubilized portion was 6%, and glucose could only be confirmed by HPLC, and only a trace amount was obtained.

[Experiment 30]
As shown in Table 4, instead of the 10 mM FeCl ₃ aqueous solution, a 10 mM iron (III) sulfate (III) (Fe ₂ (SO ₄ ) ₃ ) aqueous solution was used, and the reaction temperature was set to 200 ° C. instead of 220 ° C. Except for the above, hydrolysis reaction and glucose separation and purification were performed in the same manner as in Experimental Example 1. As a result, the solubilized component was obtained in a yield of 18% and glucose was obtained in a yield of 11%.

[Experimental example 31]
As shown in Table 4, a 10 mM aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) aqueous solution was used instead of the 10 mM FeCl ₃ aqueous solution, and the reaction temperature was changed to 200 ° C. instead of 220 ° C. In the same manner as in Experimental Example 1, hydrolysis reaction and separation and purification of glucose were performed. As a result, the solubilized component was obtained in a yield of 28% and glucose was obtained in a yield of 14%.

[Experimental example 32]
As shown in Table 4, in place of 10 mM FeCl ₃ aqueous solution, 10 mM aluminum chloride (AlCl ₃ ) aqueous solution was used, and the reaction temperature was changed to 220 ° C. to 200 ° C. Then, hydrolysis reaction and glucose separation and purification were performed. As a result, the solubilized component was obtained in a yield of 21% and glucose was obtained in a yield of 7%.

[Experimental Example 33]
As shown in Table 4, instead of the 10 mM FeCl ₃ aqueous solution, a 10 mM iron (II) chloride (FeCl ₂ ) aqueous solution was used, except that the reaction temperature was changed to 200 ° C. instead of 220 ° C. In the same manner as in No. 1, hydrolysis reaction and separation and purification of glucose were performed. As a result, the solubilized component was obtained at a yield of 5% and glucose was obtained at a yield of 2%.

In Experimental Examples 18 to 29, the yield of glucose was extremely low. Among them, in Experimental Examples 18 to 19, although the residual ratio of cellulose was low, many by-products were generated. Moreover, in Experimental Examples 20 to 29, the residual ratio of cellulose exceeded 70%, and the progress of the hydrolysis reaction was extremely insufficient. Furthermore, in Experimental Examples 18 to 20, an expensive lanthanoid-containing material is used as a metal salt, and versatility is low.
On the other hand, in Experimental Examples 14 to 17, although glucose was obtained in a good yield, as is clear from Experimental Examples 30 to 33, in the reaction system using the Lewis acid in these, glucose was slightly decreased due to a slight decrease in temperature. The yield of was greatly reduced. Among these, in Experimental Example 32, although the residual ratio of cellulose was low, many by-products were generated. In Experimental Examples 30, 31, and 33, the residual ratio of cellulose exceeded 60%, and the hydrolysis reaction was not sufficiently progressed. Thus, when the metal salt (Lewis acid) in Experimental Examples 14-17 and 30-33 is used, in contrast to the case where FeCl ₃ is used (for example, Experimental Examples 1 and 4), hydrolysis is performed. The reactivity in the process was very unstable.

  The present invention can be used for the production of glucose and ethanol.

  DESCRIPTION OF SYMBOLS 1 ... Manufacturing apparatus, 9 ... Reaction liquid, 11 ... Column, 11a ... Upstream inlet, 11b ... Downstream delivery port, 111 ... First filter, 112 ... Second filter, 12 ... Heater, 13 ... Pump, 14 ... Piping, 15 ... Liquid source reservoir, 16 ... Cooling part, 17 ... Back pressure regulator, 18 ... product reservoir, 19 ... iron (III) chloride aqueous solution

Claims (5)

A method for producing glucose by hydrolyzing cellulose,
Supplying an aqueous solution of a hydrolyzing agent to cellulose;
A method for producing glucose, comprising: a step of hydrolyzing cellulose; and a step of recovering glucose from a hydrolyzate of cellulose.   The method for producing glucose according to claim 1, wherein the hydrolyzing agent is iron (III) chloride.   The method for producing glucose according to claim 1 or 2, wherein the cellulose is crystalline cellulose.   The method for producing glucose according to any one of claims 1 to 3, wherein in the step of hydrolyzing the cellulose, the cellulose is hydrolyzed while being heated at 190 to 240 ° C. In the step of supplying the aqueous solution of the hydrolyzing agent to the cellulose, the aqueous solution of the hydrolyzing agent is supplied from the upstream side of the column containing the cellulose,
In the step of recovering glucose from the hydrolyzate of cellulose, a filter having an average pore diameter of 4 μm or less is provided on the downstream side of cellulose in the column, and glucose is recovered from the downstream side of the filter. The manufacturing method of glucose as described in any one of Claims 1-4.

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