JP2014034570A - Saccharification method, and saccharification reaction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a saccharification method which has a high yield and causes less overdecomposition of glucose during a saccharification process of producing the glucose by further hydrolyzing a solubilized liquid obtained from a biomass raw material containing cellulose, and to provide a saccharification reaction device used therefor.SOLUTION: A saccharification reaction device 10 of the present invention includes a reaction tank 20, a reaction progress measurement part 30, and a control part 40. A molecular sieve 24 through which glucose can pass is inserted between a tank upper section 21 and a tank middle section 22, and a molecular sieve 25 through which organic acids can pass is inserted between the tank middle section 22 and a tank lower section 23. A pressure pump 26 is provided in the tank upper section 21, and the control part 40 controls the pressure pump 26 according to the data signal from the reaction progress measurement part 30.

Description

  The present invention relates to a saccharification method for obtaining glucose by further hydrolyzing a solubilized liquid obtained from a biomass raw material containing cellulose, and a saccharification reaction apparatus used therefor.

  In recent years, biofuel has attracted attention as an alternative fuel for petroleum, and production of bioethanol using biomass such as sugarcane and corn has been put into practical use. However, when food is used as a raw material for bioethanol, there is a problem that the price fluctuates greatly due to competition with the food. For this reason, production of biofuels using cellulosic biomass, which is a non-food product such as wood, grass, and rice straw, as a raw material is desired.

  However, cellulose in cellulosic biomass exists as lignocellulose that is firmly bonded to lignin, and it is not easy to hydrolyze cellulose to glucose suddenly. Therefore, as a solubilization step, first, a cellulose-based biomass is hydrolyzed to a water-soluble polysaccharide by pressurized hydrothermal treatment, and the solubilized solution is further hydrolyzed to obtain glucose, which is a monosaccharide. A two-stage process has been proposed in which a saccharification step is carried out to make a solution containing sucrose (Patent Documents 1 and 2).

JP 2010-166831 A JP 2010-279255 A

  However, the conventional two-stage treatment has a problem that glucose produced in the saccharification process further reacts to cause excessive decomposition, resulting in poor yield of glucose.

  This invention is made | formed in view of the said conventional situation, and makes it a subject to provide the saccharification method of the saccharification method of a solubilizing solution with which it is hard to produce the excessive decomposition | disassembly of glucose and a yield, and its saccharification reaction apparatus.

A first aspect of the saccharification reaction apparatus of the present invention is a saccharification reaction apparatus for obtaining glucose by hydrolyzing a solubilized liquid containing a water-soluble polysaccharide obtained from a biomass raw material containing cellulose. A reaction progress measuring means for measuring the progress of the saccharification reaction of the lysate, a glucose separating means for separating the glucose, a control means for controlling the glucose separating means according to the progress of the saccharification reaction, It is provided with.
The first aspect of the saccharification method of the present invention is a saccharification method for obtaining glucose by hydrolyzing a solubilized liquid containing a water-soluble polysaccharide obtained from a biomass raw material containing cellulose. While performing, the progress of the saccharification reaction of the solubilized solution is judged by the concentration of glucose, and glucose is separated.

  In the saccharification reaction apparatus and the saccharification method according to the first aspect of the present invention, glucose produced by hydrolysis of the water-soluble polysaccharide in the solubilized liquid is quickly separated from the reaction system by the glucose separation means. Moreover, based on the measurement result of the reaction progress measuring unit for measuring the progress of the saccharification reaction of the solubilized solution, the glucose can be separated by the glucose separating means before the excessive decomposition reaction of glucose becomes significant. For this reason, the excessive decomposition product of glucose can be decreased while maintaining the production rate of glucose at a high level. Therefore, it is possible to prevent glucose from further causing a hyperdegradation reaction to become a hyperdegradation product such as hydroxymethylfurfural, acetic acid, and lactic acid, and the yield of glucose is also improved.

  The progress of the saccharification reaction of the solubilized solution can be estimated from the hydrogen ion concentration, the glucose concentration, etc. of the solubilized solution. For this reason, in the second aspect of the present invention, the reaction progress measuring means is an apparatus that detects and measures the progress of the saccharification reaction by concentration.

  The hydrogen ion concentration can be measured with a pH measuring device, and the glucose concentration can be measured with an optical rotation measuring device. For this reason, in the saccharification reaction device of the third aspect, the reaction progress measurement unit has a pH measurement device and / or an optical rotation measurement device. In addition, as an apparatus for measuring the glucose concentration, an enzyme sensor for measuring glucose concentration using glucose oxidase may be used instead of the optical rotation measuring device.

  Moreover, the separation of glucose from the solubilized solution can be performed using a molecular sieve such as zeolite. For this reason, in the saccharification reaction apparatus of the fourth aspect, the separation of glucose is performed by a molecular sieve.

It is process drawing for manufacturing a saccharified liquid from a cellulose containing biomass raw material including saccharification process S5 of embodiment. It is a schematic diagram of the saccharification reaction apparatus of the solubilization liquid of embodiment. It is a schematic diagram of the reaction progress measurement part 30 part of the saccharification reaction apparatus of the solubilization liquid of embodiment. 3 is a flowchart of control performed by a control unit 40.

<Preparation of solubilized solution>
A solubilized liquid containing a water-soluble polysaccharide obtained from a biomass raw material containing cellulose, which is a raw material in the saccharification method of the present invention, is prepared as follows (see FIG. 1).
(material)
The raw material containing cellulose is a plant-based raw material containing cellulose, and it can be used even if it contains polysaccharides other than cellulose, such as starch, hemicellulose, and pectin, in addition to cellulose. Specifically, grasses such as rice straw, wheat straw, bagasse, thinned timber such as bamboo and firewood, sawn wood, chips, wood chips such as wood chips, pruned roadside trees, wood construction waste, bark, driftwood, etc. Examples include woody biomass and biomass from cellulose products such as waste paper. In addition, sludge, livestock excrement, agricultural waste, municipal waste, etc. can be used as long as cellulose can be used as a raw material.

・ Rough grinding process (S1)
In order to promote solubilization of cellulose, these raw materials are preferably subjected to coarse pulverization as a pretreatment to reduce the crystallinity of cellulose. The pulverization method is not particularly limited, and an appropriate method may be appropriately selected according to the form of the raw material, but first, it is roughly pulverized to several to several tens of millimeters to be easily handled, and then further finely pulverized. Fine grinding can be performed efficiently. A general-purpose pulverizer such as a hammer mill or a cutter mill can be used for coarse pulverization. For fine pulverization, general-purpose pulverizers such as a vibration mill, ball mill, rod mill, roller mill, colloid mill, disc mill, jet mill, etc. can be used. Can be reduced. As the pulverization treatment, both dry and wet methods can be applied, but dry pulverization is desirable in terms of reducing the crystallinity of cellulose. When the water content of the raw material is large, the crystallinity of cellulose can be effectively reduced by dry pulverization after the water content is reduced to 30% or less in advance by centrifugal dehydration or hot air drying.

・ Moisture adjustment process (S2)
After measuring the moisture content of the raw material after the coarse pulverization, the moisture content is adjusted. If the water content is too high, dry it. If the water content is low, add water. An appropriate method for calculating the water content will be described in the next solubilization step.

・ Solubilization step (S3)
Then, the coarsely pulverized raw material with the adjusted water ratio is made into a solubilized mixture containing an organic acid by controlling the temperature and pressure. Examples of temperature and pressure control include 1) a control method for performing hydrothermal treatment, and 2) a control method at low temperature and low pressure.
Hydrothermal treatment is a process that makes cellulose-containing biomass raw materials water-soluble with pressurized hot water (high-temperature and high-pressure water that exists in a liquid state) pressurized to a saturation water vapor pressure or higher. Process. In the subcritical region, the total pressure is higher than the saturated water vapor pressure. In other words, water is a region where water stably coexists as liquid water in addition to water vapor. For this reason, it is presumed that the hydrolysis reaction of cellulose in the subcritical region proceeds with liquid water having a large ionic product. In addition, the hydrolysis reaction of cellulose in the supercritical region is a hydrolysis reaction with water in a special state called a supercritical state where gas-liquid cannot be distinguished. Pressurized hot water is thought to accelerate the hydrolysis reaction of cellulose because of an increased ionic product. For this reason, the hydrothermal treatment method has the advantage that the cellulose raw material can be solubilized in a short time without using a special chemical, and is said to be a solubilizing method of the cellulose raw material with a small environmental load. be able to. The amount of organic acid produced can be controlled by controlling temperature, pressure and reaction time.

  On the other hand, the control method at low temperature and low pressure uses a temperature-pressure region which is completely different from that of hydrothermal treatment. That is, it is characterized in that the hydrolysis reaction is carried out in a low temperature-low pressure region where the total pressure is from 0.05 MPa to less than 10 MPa. Such a region is a region where the total pressure is smaller than the saturated water vapor pressure (that is, a region where water does not exist stably and only water vapor exists), or liquid water and water vapor coexist, but the total pressure is This is a small region of less than 10 MPa, and is completely different from the subcritical region and supercritical region. Also in this method, organic acids such as lactic acid and acetic acid can be generated in addition to the solubilized sugar, and these organic acids can be used as a catalyst in the saccharification step (S5) described later. The amount of organic acid to be generated can be controlled by controlling the amount of water to be added, temperature, pressure, reaction time, and the like. This low temperature and low pressure control method produces less overdegradation products such as hydroxymethylfurfural (HMF) than the method using pressurized hot water, and can increase the final saccharification yield.

In the solubilization step (S3), a closed vessel with a lid can be used as the reaction vessel in order to control temperature and pressure. As such a container, a double-structure container such as an autoclave apparatus made of a corrosion-resistant metal or a metal pressure-resistant container that houses a lidded container made of a fluororesin such as PTFE can be used.
Then, a predetermined amount of the coarsely pulverized raw material and water adjusted in the water ratio are put into these containers, and the lid is closed to set the temperature. As a result, the water originally contained in the raw material and the added water become water vapor and increase in volume. At this time, the finally reached pressure can be easily obtained by substituting the temperature, the amount of water, and the container volume into the state equation corrected for the actual gas. For this reason, the water | moisture content adjustment of the pulverized cellulose raw material performed prior to a solubilization process is performed so that it may become the quantity calculated | required by calculation. The heating method is not particularly limited, and an electric heater, high frequency, microwave, steam, or the like can be used.

・ Extraction process (S4)
Water is added to the solubilized mixture thus obtained in an amount of 0.1 to 500 times to dissolve, and solid-liquid separation is performed to obtain a solubilized solution.

<Saccharification of solubilized solution>
The saccharification step S5 of the embodiment described below is performed using the solubilized solution obtained as described above, and the solubilized solution is further hydrolyzed to obtain a saccharified solution containing glucose.
(Saccharification process S5)
In the saccharification step S5, the saccharification reaction apparatus 10 shown in FIG. 2 can be used. The saccharification reaction apparatus 10 includes a reaction tank 20, a reaction progress measurement unit 30, and a control unit 40.

  The reaction tank 20 is divided into a tank upper part 21, a tank middle part 22, and a tank lower part 23, and glucose molecules can pass between the tank upper part 21 and the tank middle part 22, but water-soluble polysaccharides such as oligosaccharides A molecular sieve 24 made of zeolite that cannot pass is inserted. In addition, a molecular sieve 25 made of zeolite is inserted between the middle tank portion 22 and the lower tank portion 23 so that low molecular organic acids such as acetic acid and lactic acid can pass but glucose molecules cannot pass. A pressurizing pump 26 for pressurizing the inside of the tank upper portion 21 is provided at the upper end of the tank upper portion 21. Furthermore, a charging port 27 for charging the solubilizing liquid is attached to the upper end of the side wall of the tank upper portion 21. In addition, an electromagnetic valve V1 is attached to the lower end of the tank upper part 21, an electromagnetic valve V2 is attached to the lower end of the tank middle part 22, and an electromagnetic valve V3 is attached to the lower end of the tank lower part 23.

  As shown in FIG. 3, the reaction progress measurement unit 30 has a U-shaped channel 31 attached to the side surface of the reaction tank 20 so as to communicate with the inside, and a pH sensor is provided in the middle of the channel 31. 32 is inserted. Further, quartz glass windows 35a and 35b are attached in the middle of the flow path 31 so as to face each other in the radial direction. A light source 34, polarizing plates 33a and 33b, and an analyzer are disposed outside the quartz glass windows 35a and 35b. An optical rotation meter 37 consisting of 36 is attached. Further, strainers 38 a and 38 b for preventing the solid acid catalyst from entering the flow path 31 are attached to the entrance and exit of the flow path 31.

  The control unit 40 can control the pressurizing pump 26 (see FIG. 2) in accordance with outputs from the pH sensor 32 and the polarimeter 37.

  In the saccharification reaction apparatus 10 shown in FIG. 2 configured as described above, the solubilized liquid and the solid acid catalyst obtained in the extraction step S4 are input from the input port 27. Then, the inside of the tank upper portion 21 is heated by a heater (not shown) while stirring the solubilized liquid by a stirring device (not shown). At this time, the pH is measured by the pH sensor 32 in the flow path 31 communicating with the tank upper part 21, and at the same time, the optical rotation is measured by the polarimeter 37. Data signals of these measurement results are transmitted to the control unit 40.

Based on these data signals, the control unit 40 controls the pressurizing pump 26, the electromagnetic valve V1, and the heater according to the flowchart shown in FIG.
That is, first, in step S101, the control unit 40 determines whether or not a certain amount of water-soluble polysaccharide that can be saccharified exists based on the data signal from the polarimeter 37. For this purpose, a calibration curve indicating the relationship between the optical rotation in the saccharification step S5 and the amount of water-soluble polysaccharide that can be saccharified is prepared in advance, and a threshold value for optical rotation is set.

  When the optical rotation does not exceed the threshold (that is, when the water-soluble polysaccharide that can be saccharified has a predetermined concentration or more), the heater is kept on and the process proceeds to step S102. In step S102, based on the measurement data from the pH sensor 32, the control unit 40 determines whether or not the pH is equal to or lower than the threshold value (that is, the glucose has reached a state in which excessive decomposition occurs). For this purpose, a calibration curve showing the relationship between the pH of the solubilized solution in the saccharification step S5 and the amount of overlysate is prepared in advance, and a threshold value for pH is set. And when pH value exceeds this threshold value, the ON state of a heater is continued and saccharification process S5 is continued. Further, when the pH is lower than the threshold value (that is, when the glucose has reached a state of causing excessive decomposition), the control unit 40 drives the pressurizing pump 26 to solubilize the liquid in the tank upper portion 21. Among the water-soluble polysaccharide, glucose and organic acid contained therein, the glucose and organic acid are separated by the molecular sieve 24. In this way, glucose and organic acid enter the middle part 22 of the tank, and further, the organic acid is separated by the molecular sieve 25 and moves to the lower part 23 of the tank. Thereby, glucose is stored in the tank middle part 22, and organic acid is stored in the tank lower part 23.

  On the other hand, when the optical rotation exceeds the threshold value in step S101 (that is, when the water-soluble polysaccharide is less than or equal to the predetermined concentration), the heater is turned off, the electromagnetic valve V1 is opened, and the saccharified solution is removed from the solid acid catalyst. Then, the saccharification step S5 is completed.

  As described above, in the saccharification reaction apparatus of the embodiment, the optical rotation of the solubilized liquid in the tank upper part 21 is monitored by the optical rotation meter 37, and the end point of the saccharification step S5 is determined while considering the concentration of the water-soluble polysaccharide. Therefore, the saccharification step S5 is prevented from being performed unnecessarily for a long time. Further, the pH of the solubilized liquid in the tank upper part 21 is monitored by the pH sensor 32, and the glucose is separated by the molecular sieve 24 so that the glucose is not easily excessively decomposed while considering the pH of the solubilized liquid. To do. For this reason, excessive decomposition of glucose does not easily occur, and the yield of glucose is improved. Moreover, since the separation of glucose and the saccharification reaction of the solubilized solution can be performed simultaneously in parallel, the saccharification step can be efficiently performed in a short time.

  The present invention is not limited to the description of the embodiment of the invention. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

Claims (5)

A saccharification reaction apparatus for obtaining glucose by hydrolyzing a solubilized liquid containing a water-soluble polysaccharide obtained from a biomass raw material containing cellulose,
Reaction progress measuring means for measuring the progress of the saccharification reaction of the solubilized liquid, glucose separating means for separating the glucose, and control means for controlling the glucose separating means according to the progress of the saccharification reaction And a saccharification reaction apparatus.   The saccharification reaction apparatus according to claim 1, wherein the reaction progress degree measuring means is an apparatus for detecting and measuring the progress degree of the saccharification reaction by concentration.   The saccharification reaction apparatus according to claim 2, wherein the reaction progress measurement means is a pH measurement apparatus and / or an optical rotation measurement apparatus.   The saccharification reaction apparatus according to any one of claims 1 to 3, wherein the glucose separation means is a molecular sieve. A saccharification method for obtaining glucose by hydrolyzing a solubilized liquid containing a water-soluble polysaccharide obtained from a biomass raw material containing cellulose,
A saccharification method characterized in that glucose is separated by judging the progress of the saccharification reaction of the solubilized solution based on the glucose concentration while performing hydrolysis.

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