WO1998021217A1

WO1998021217A1 - Process for the preparation of glucose from vegetable fibrous materials

Info

Publication number: WO1998021217A1
Application number: PCT/JP1996/003319
Authority: WO
Inventors: Seiji Hata
Original assignee: Tsurunaga, Takehisa; Suzuki, Yasutaka
Priority date: 1996-11-12
Filing date: 1996-11-12
Publication date: 1998-05-22
Also published as: AU7507496A

Abstract

The use of oxo acids of phosphorus as the solvent enables the dissolution of difficulty soluble vegetable fibrous materials. Glucose can be prepared in a high yield by dissolving a vegetable fibrous material in a solvent comprising an oxo acid of phosphorus, neutralizing the obtained solution with an inorganic acid catalyst or an alkaline solution, and bringing the resulting solution into contact with an enzyme to thereby efficiently hydrolyze the polysaccharides contained in the vegetable fibrous material under such mild conditions as not to cause any seconday decomposition. The solvent to be used in the dissolution of vegetable fibrous materials is preferably one comprising an aqueous solution of at least one member selected from the group consisting of phosphoric acid, phosphonic acid, phosphinic acid and metaphosphoric acid, with the concentration being 70 % by weight or above.

Description

Description Method for producing glucose from plant fiber material

The present invention relates to a method for producing glucose from a plant fiber material by dissolving a plant fiber material such as cellulose in a solvent.

Background art

Plant fiber materials contain cellulose as a polysaccharide, and glucose, the basic constituent unit of cellulose, is expected to be used as a food or energy source. Therefore, if glucose can be produced efficiently by efficiently decomposing not only cereals but also plant fiber materials, it will lead to effective use of waste such as waste paper. Conventionally, as a method for decomposing cellulose, a hydrolysis method using an acid or an enzyme is known. Examples of the acid hydrolysis method (hereinafter referred to as “acid method”) include various extraction methods using dilute sulfuric acid or concentrated sulfuric acid, and methods using hydrogen chloride in concentrated hydrochloric acid or in a gaseous state. As an enzymatic hydrolysis method (hereinafter referred to as “enzymatic method”), there is a method in which wood fragments are pretreated with wood flour and then enzymatically reacted with cellulase. In the acid method and the enzymatic method, although various measures are taken for the reaction conditions, etc., the contact with the reaction solvent becomes insufficient because the cell mouth, which is the substrate to be hydrolyzed, is in a non-dissolved state. There is a disadvantage that the hydrolysis requires a long time.

In addition, it is considered that the difficulty of hydrolysis of cellulose is due to its crystallinity. Cellulose is a natural macromolecule in which glucose is bound to a / 3-1,4-glycosidic bond. Cellulose fibers are water-insoluble, although glucose, which is a structural unit of cellulose, is inherently hydrophilic. This is thought to be due to the fact that the cellulose molecules associate and crystallize due to strong hydrogen bonds.

Incidentally, it is said that the yield of crystalline cellulose (Abicel, manufactured by Asahi Kasei Corporation) obtained by hydrolyzing the amorphous region of cellulose fibers with dilute sulfuric acid is 90%. This indicates that the crystalline region exists in the cellulose fiber at a value close to 90%. This crystalline cellulose is treated with, for example, 3N hydrochloric acid at room temperature. Even after one week, no significant change occurs even if the mixture is vigorously stirred. In addition, when this is boiled, partial hydrolysis is observed, but at the same time decomposition of produced glucose is observed. Thus, the crystalline region has high resistance to hydrolysis.

Therefore, first, if it is possible to dissolve the cellulose fiber in the solvent, it is considered that the subsequent hydrolysis will proceed efficiently. Various methods for dissolving cellulose have been proposed, but these known methods were developed mainly for producing fiber products and film products. Since it dissolves this, it is not suitable for obtaining glucose by hydrolysis.

In addition, it is generally known that a polymer having an alcohol residue, for example, polyvinyl alcohol, increases solubility by alkaligenization. However, although cellulose swells with alkali, it does not dissolve under mild conditions. Furthermore, it has been reported that hydrazine and N-methylmorpholine oxide dissolve cellulose, but such solutions are not suitable for hydrolysis.

As described above, cellulose is difficult to dissolve in alkali due to its crystallinity. In particular, hydrolysis by alcohol does not only require a long time, but also causes side reactions such as a peeling reaction to occur, thereby reducing the production of glucose. Decrease rate. Although a method of dissolving with an organic solvent has been proposed, a method suitable for obtaining dalcose by subsequent hydrolysis has not been found.

The present invention has been made to solve the above-described problems, and has found that a plant-based fiber material including cellulose fibers can be easily dissolved by an aqueous solution of oxoacid of phosphorus, and the dissolved liquid is used to hydrolyze cellulose and the like. The present invention provides a method for producing glucose with a high yield by hydrolyzing a plant fiber material with high efficiency and under relatively mild conditions. is there

Disclosure of the invention

In order to solve the above problems, a method for producing glucose according to the present invention is characterized in that a plant fiber material is dissolved in a solvent containing oxoacid of phosphorus. In a preferred embodiment of the present invention, the solvent contains at least one aqueous solution selected from the group consisting of phosphoric acid, phosphonic acid, phosphinic acid and metaphosphoric acid, and has a concentration of 70% by weight or more.

In another preferred embodiment of the present invention, the dissolved solution is neutralized with an inorganic acid catalyst or an alkaline solution and then contacted with an enzyme to hydrolyze polysaccharides such as cellulose contained in the plant fiber material, It produces glucose.

In still another preferred embodiment of the present invention, the hydrolysis reaction catalyst is an inorganic acid catalyst comprising hydrogen halide or concentrated sulfuric acid, and hydrogen halide power is particularly preferred. In still another preferred embodiment of the present invention, a metal halide salt can be added during or after dissolving the plant fiber material in a solvent to generate hydrogen halide as an acid catalyst. .

First, a method for dissolving the plant fiber material will be described below. Examples of the oxo acid of phosphorus as a solvent include phosphoric acid, phosphonic acid, phosphinic acid and metaphosphoric acid, and a mixed solvent composed of any combination of these may be used. These oxo acids of phosphorus act not as acids as so-called proton donors but as solvents such as cellulose. This is evident from the fact that phosphoric acid and the like are different from sulfuric acid and the like, and the same glucose as cellulose has a low solubility and low solubility in starch with α-1,4-darcoside linkage. That is, a plant fiber material such as cellulose can be dissolved in an oxoacid-based solvent of phosphorus without being substantially decomposed.

The concentration of the oxo acid of phosphorus used in the present invention is desirably 0% by weight or more, and particularly preferably in the range of 70 to 85% by weight. Also, the amount of these used is not particularly limited, but it is usually preferable to use 5 to 15% by weight of the plant fiber material to be dissolved.

The dissolution can be carried out at room temperature, but may be carried out by heating to a temperature of up to 60 ° C., preferably in the range of 30 to 60 ° C. As a dissolution method, an ordinary method such as a stirring and mixing method is used, and is not particularly limited.

In order to perform the hydrolysis of the plant fiber material thus dissolved with high efficiency, it is preferable to uniformly dissolve the plant fiber material in the oxo acid solvent of phosphorus. Such uniform dissolution can be confirmed by visual observation that no change in the viscosity of the solution is observed and no insoluble substance remains.

In the next step, the lysate obtained as described above is neutralized with an inorganic acid catalyst (excluding phosphorus oxo acid) or an alkaline solution and then brought into contact with an enzyme to hydrolyze the plant fiber material. Let it break down. As the inorganic acid catalyst to be used, those having a small amount of water are preferable in order to prevent the formation of a white precipitate due to addition, contact and the like. Hydrogen halide or sulfuric acid is suitably used, and a mixture thereof may be used, but hydrogen halide is particularly preferably used. Note that an aqueous hydrochloric acid solution that easily produces a white precipitate is not preferable. Hydrogen halide can be used as a gas state, and examples thereof include hydrogen chloride gas, hydrogen bromide gas, and hydrogen fluoride gas. A particularly preferred inorganic acid catalyst is hydrogen chloride gas. The amount of inorganic acid catalyst used is based on the amount of vegetable fiber material used.

It is preferably used in a proportion of 5 to 20% by weight.

Further, an enzyme may be used for the hydrolysis. For example, in the decomposition of cellulose, the same hydrolysis effect as when using an inorganic acid catalyst can be obtained by an enzymatic reaction using cellulose.

The hydrolysis is carried out while adding an enzyme solution after neutralizing the solution of the plant fiber material with a catalyst solution of an inorganic acid or a solution of the inorganic acid with an alkali solution. The reaction temperature is not particularly limited, but it is preferable to carry out the reaction under relatively mild temperature conditions of 40 to 80 ° C. When using gaseous hydrogen halide, add hydrogen halide by blowing gas into the solution. The hydrolysis reaction depends on the amount of the plant fiber material to be used, but usually can be completed in 30 minutes to 3 hours.

In the present invention, it is also possible to add a metal halide to the solution during or after dissolving the plant fiber material in the solvent, and to generate hydrogen halide as an acid catalyst simultaneously with the dissolution. Thus, hydrolysis can be performed in the same manner as when an acid catalyst is added. Since the metal halide is dissolved in the solution to generate the corresponding hydrohalic acid, there is an advantage that an easy-to-handle metal salt can be used instead of directly using a difficult-to-handle hydrogen halide gas. Note that such metal salts include halogens such as sodium, lithium, magnesium, and aluminum. Compounds. For example, lithium chloride, magnesium chloride, aluminum chloride, and the like are used to generate hydrogen chloride, and lithium bromide and the like are used to generate hydrogen bromide to generate hydrogen fluoride. For example, lithium fluoride or the like is used. These metal halide salts may be added during or after dissolution of the plant fiber material with the oxo acid-based solvent of phosphorus.

Finally, after the completion of the hydrolysis reaction, the reaction mixture is filtered using an ion exchange resin or an ion exchange membrane, and the filtrate is concentrated to obtain glucose crystals. In addition, as a filtration method, a reverse osmosis method, an ultrafiltration method, an electrodialysis method, or the like can be used.

As the plant fiber material used in the present invention, paper, wood, etc., not to mention cellulose itself, can be used, preferably in the form of finely pulverized powder.

As described above, according to the present invention, a plant fiber material containing cellulose fibers is efficiently hydrolyzed under relatively mild reaction conditions in which no force, no secondary decomposition occurs, and good darcos is obtained. It can be produced with a high yield.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments according to the present invention will be described in detail.

Example 1

50 g of an 85% phosphoric acid aqueous solution was added to 5 g of the crystalline cellulose powder, and the mixture was sufficiently stirred. As the crystalline cellulose powder dissolved in the aqueous phosphoric acid solution, the viscosity of the solution gradually decreased. Stirring was continued until this change in viscosity was no longer observed. After visually confirming that the cellulose powder was completely dissolved in the phosphoric acid aqueous solution and did not remain, the mixture was left until the mixed air bubbles were removed. Thus, a solution in which cellulose was dissolved in the solvent was obtained.

3 g of lithium chloride was added to the aqueous phosphoric acid solution of cellulose thus prepared, and dissolved while stirring at room temperature. At this time, it was confirmed that ammonia chloride white smoke was generated when the ammonia water was brought close to the solution, and that ammonia chloride odor was generated due to the smell of ammonium chloride. Then, after stirring at room temperature for 20 minutes, the solution was heated to 80 ° C for 5 minutes, and further stirred for 30 minutes, and turned yellow. A solution was obtained. After allowing this solution to cool to room temperature, the solution was passed through a column filled with an ion exchange resin (manufactured by Organo, trade name: Amberlite), and a colorless and transparent solution flowing out was collected. This solution was concentrated under reduced pressure to about 2 _Om1 to obtain 4 _g of a white precipitate. The Fehling reaction test and the enzyme electrode method confirmed that this white precipitate was glucose.

Example 2

According to the procedure of Example 1, 3 g of waste paper powder was dissolved in 30 g of an 85% phosphoric acid aqueous solution. Thereafter, a hydrolysis reaction and post-treatment were carried out according to the same procedure as in Example 1 except that 3 ml of concentrated sulfuric acid was added to this solution instead of lithium chloride, to obtain 2.4 g of glucose.

Example 3

When 40 g of an 85% phosphoric acid aqueous solution was added to 5 g of the cellulose powder and sufficiently stirred, a syrup-like solution was obtained. 5 g of lithium chloride was added thereto and kneaded. The container containing the kneaded material is heated to 80 ° C in a water bath, and the container is kept covered with the lid so that the vapor containing hydrogen chloride gas generated in the container comes into contact with the syrup-like cellulose. Hold for minutes. After visually confirming that the starch syrup had turned into a solution, a small amount thereof was taken out, water was added thereto, and the hydrolysis reaction was continued until the syrup did not become cloudy. After completion of the reaction, the solution was diluted by adding water 2 Om 1, passed through a column filled with ion exchange resin (manufactured by Organo, trade name: Amberlite), and the effluent was concentrated to obtain crude glucose 4. g was obtained.

Example 4

Distilled water (1 Om1) was added to waste paper powder (10 g), and distilled water was sufficiently absorbed in the waste paper powder. Then, 30 g of an 85% phosphoric acid aqueous solution was added and kneaded sufficiently. This kneaded material was heated to 50 to 60 ° C., and kneading was continued to obtain a paste. After the paste was cooled to room temperature, the mixture was sufficiently stirred while blowing hydrogen chloride gas. This was placed in a closed container, heated to 80 ° C, and stirring was continued in that state while degassing. After completion of the hydrolysis reaction was confirmed in the same manner as in Example 3, post-treatment was performed to obtain crude glucose 7.

Claims

The scope of the claims

1. A method for producing glucose from a plant fiber material, comprising dissolving the plant fiber material in a solvent containing oxo acid of phosphorus.

2. The solvent according to claim 1, wherein the solvent contains at least one aqueous solution selected from the group consisting of phosphoric acid, phosphonic acid, phosphinic acid and metaphosphoric acid, and has a concentration of 70% by weight or more. A method for producing glucose from a plant fiber material according to claim 1.

3. A solution prepared by dissolving the plant fiber material in a solvent containing oxo acid of phosphorus is neutralized with an organic acid catalyst or an alkaline solution, and then contacted with an enzyme to remove polysaccharides contained in the plant fiber material. 3. The method for producing glucose from a plant fiber material according to claim 1, wherein glucose is produced by hydrolysis.

4. The method for producing glucose from a plant fiber material according to claim 3, wherein the inorganic acid catalyst comprises at least one of hydrogen halide and concentrated sulfuric acid.

5. The method for producing glucose from a plant fiber material according to claim 3, wherein the inorganic acid catalyst comprises hydrogen halide.

6. The glucose from the plant fiber material according to claim 5, wherein a metal halide is added during or after dissolving the plant fiber material in a solvent to generate hydrogen halide. How to manufacture.