CN102093435A - Method for extracting arabinose from arabinose-containing mixed sugar - Google Patents

Abstract

The invention provides a method for extracting arabinose from mixed sugar containing arabinose, wherein the mixed sugar also contains xylose or rhamnose, the xylose and the arabinose or the rhamnose and the arabinose coexist in organic solvent solutions with different water contents, the crystallization characteristics are different after the dissolution and the cooling, the complete separation of the xylose and the arabinose is realized through simple dissolution and crystallization processes, the dependence on a chromatographic separation method is eliminated, and the foundation is laid for the large-scale preparation of the arabinose.

Description

A method for extracting arabinose from arabinose-containing mixed sugar

technical field

The invention belongs to the field of chemical industry, and in particular relates to a method for extracting arabinose from arabinose-containing mixed sugar, wherein the mixed sugar also contains xylose or rhamnose.

Background technique

L-arabinose is a five-carbon sugar with a wide range of uses, mainly in the form of polymers in plant hemicellulose. The dry matter of higher plants generally contains about 20-35% hemicellulose, and hemicellulose is mainly composed of xylose and arabinose. In addition, L-arabinose also exists in a large amount in plant gums such as gum arabic. Due to the huge yield of hemicellulose, xylose and arabinose can be produced in large quantities by hydrolyzing hemicellulose in higher plants.

The hemicellulose hydrolyzate contains a variety of monosaccharides, mainly xylose, as well as glucose, arabinose, and galactose. Since most of the monosaccharides in the hemicellulose hydrolyzate are xylose, xylose crystallization can be separated by crystallization until the xylose cannot be recrystallized, and the remaining mother liquor that cannot be crystallized is called xylose mother liquor. According to liquid chromatography analysis (Anhui Agricultural Science, 2009, 37 (5): 1881-1882, "The composition of xylose mother liquor determined by PHLC method"), xylose mother liquor contains 38.10% xylose, 23.70% arabinose, 13.80% Dextrose, 9.89% galactose. At present, the separation and extraction of arabinose from xylose mother liquor generally adopts simulated moving bed chromatographic separation technology. Due to the large investment in equipment of this technology, but the production capacity is very small, arabinose cannot meet the market demand.

In addition to being mainly prepared from the hydrolysis of hemicellulose, arabinose can also be prepared from some plant gums containing arabinose, such as gum arabic. According to the analysis, the monomer composition of gum arabic is: galactose 42%, L-arabinose 31%, rhamnose 13%, glucuronic acid 13%, 4-O-methyl glucuronic acid 1%. For example, Chinese patent 02116353.7 discloses a method for extracting arabinose from gum arabic, but the mixed monosaccharides still need to be separated by two-column chromatography to obtain arabinose, which is difficult to industrialize. The separation method described in the paper "Crystalization and separation of L-arabinose from gum arabic hydrolyzate" (Chemical Industry and Engineering, 2007, 24(5): 398-400) is: the hydrolyzate obtained by hydrolyzing and neutralizing the gum arabic dilute sulfuric acid Galactose is removed by fermentation, and then crude arabinose is obtained by crystallization and separation in methanol, and then ethanol is added to the crude arabinose aqueous solution to crystallize to obtain 97.5% arabinose. In this method, since the arabinose in the methanol crystallization mother liquor and the ethanol crystallization mother liquor cannot be separated and recovered, the yield is not high, the highest is only 50% of the theoretical yield, and thus the cost is relatively high.

Owing to adopting existing method to prepare arabinose not only output is small but also cost remains high, thereby has limited the popularization and use of this functional sugar with good health care function. To this end, a large-scale production method for arabinose needs to be developed.

Contents of the invention

In order to overcome the above disadvantages, the present invention provides a method for extracting arabinose from arabinose-containing mixed sugar, wherein the mixed sugar also contains xylose or rhamnose, which utilizes xylose or rhamnose and arabinose The solubility in hot organic solvents with different water contents and the crystallization rate after cooling are different, and the complete separation of xylose or rhamnose from arabinose is realized through a simple dissolution and crystallization process, laying the foundation for large-scale preparation of arabinose Base.

The technical scheme of the present invention is as follows: a method for extracting arabinose from arabinose-containing mixed sugar, wherein the mixed sugar also contains xylose or rhamnose, the method comprising the following steps:

(1) Take the above-mentioned mixed sugar containing arabinose as the initial sugar;

(2) Mix the initial sugar with water or the aqueous solution of the first organic solvent, and heat to partially dissolve the initial sugar. The water content of the aqueous solution of the first organic solvent is to obtain the ratio of xylose content to arabinose content or rhamnose The ratio of content to arabinose content is less than or approximately equal to the water content required for crystal a of 1:1, and the amount of the water or the aqueous solution of the first organic solvent is about the complete dissolution of arabinose in the initial sugar under the heating conditions required amount, mixture I was obtained;

(3) separating mixture I from solid to liquid to obtain sugar solution a and crude xylose, or to obtain sugar solution a and crude rhamnose;

(4) Sugar solution a crystallizes after cooling, and crystallization a and crystallization mother liquor a are obtained by separation, wherein, in said crystal a, the ratio of xylose content to arabinose content or the ratio of rhamnose content to arabinose content is less than or about Equal to 1:1;

(5) Mix crystal a with the second organic solvent or the aqueous solution of the second organic solvent, heat to partially dissolve the crystal a, and the amount of the second organic solvent or the aqueous solution of the second organic solvent is about The amount required for the complete dissolution of xylose or rhamnose in crystal a to obtain mixture II;

(6) The mixture II is separated from solid and liquid to obtain sugar solution b and crude arabinose.

In step (2), when the arabinose in the initial sugar is completely dissolved, the xylose or rhamnose is also completely dissolved, and the arabinose is extracted from the initial sugar from step (5).

The method for extracting arabinose from the mixed sugar containing arabinose and xylose or rhamnose also includes the following steps:

(7) cooling the sugar solution b to crystallize, and separating crystal b and crystal mother liquor b;

(8) Using crystal b as the initial sugar, repeat the above steps (2) to (7) until all the arabinose in the arabinose-containing mixed sugar is extracted.

The step (3) of the solid-liquid separation of the mixture I and/or the step (6) of the solid-liquid separation of the mixture II is carried out under the condition of heat preservation.

When the sugar solution a or the sugar solution b is difficult to crystallize, a third organic solvent is added to the sugar solution a or the sugar solution b as a crystallization accelerator, and the third organic solvent is selected from alcohol, ethers and ketones.

Preferably, the crystallization mother liquor a is reused as the water described in step (2) or the aqueous solution of the first organic solvent, and the crystallization mother liquor b is reused as the second organic solvent described in step (5) or the aqueous solution of the first organic solvent. The aqueous solution of the second organic solvent mentioned above, but when the crystallization accelerator is added, first separate and remove the crystallization accelerator and then reuse it.

When the sugar solution a or the sugar solution b is difficult to crystallize, the sugar solution a or the sugar solution b is evaporated to remove part or all of the solvent.

The arabinose-containing mixed sugar is a monosaccharide mixture prepared from hemicellulose hydrolyzate.

Preferably, the arabinose-containing mixed sugar is a monosaccharide mixture prepared from a xylose mother liquor after xylose is crystallized from a hemicellulose hydrolyzate.

Preferably, the arabinose-containing mixed sugar is a monosaccharide mixture prepared by fermenting xylose mother liquor after crystallizing xylose from hemicellulose hydrolyzate to remove glucose.

Preferably, the arabinose-containing mixed sugar is a monosaccharide mixture prepared by fermenting xylose mother liquor after crystallizing xylose from hemicellulose hydrolyzate to remove glucose and galactose.

The arabinose-containing mixed sugar is a monosaccharide mixture prepared by fermenting and removing galactose with arabic gum hydrolyzate.

Both the first organic solvent and the second organic solvent are selected from alcohols, ketones, carboxylic acids, nitrogen-containing organic solvents, polyfunctional compounds containing several functional groups in hydroxyl, ketone, and carboxyl, and several of them mixture of species.

The first organic solvent and/or the second organic solvent may further contain other organic solvents.

The alcohol is selected from C1-C3 alcohols, the ketone is selected from acetone and butanone, the carboxylic acid is selected from C1-C4 carboxylic acids, and the nitrogen-containing organic solvent is selected from acetonitrile and pyridine.

Preferably, the crystal a is washed with a cold organic solvent or an aqueous solution of a cold organic solvent before being mixed with the second organic solvent or the aqueous solution of the second organic solvent; the crystal b is mixed with the water or The aqueous solution of the first organic solvent is washed with a cold organic solvent or a cold aqueous solution of an organic solvent before being mixed.

Preferably, the crystal a is dried before being mixed with the second organic solvent or the aqueous solution of the second organic solvent; the crystal b is dried before being mixed with the water or the aqueous solution of the first organic solvent. to dry.

Preferably, the obtained crude arabinose, crude xylose or crude rhamnose is recrystallized to obtain pure arabinose, pure xylose or pure rhamnose.

The present invention uses the mixed sugar obtained from hemicellulose hydrolysis as the raw material, or the monosaccharide mixture prepared from the xylose mother liquor after the xylose is crystallized from the hemicellulose hydrolyzate, or uses the mixed sugar obtained from the hydrolysis of gum arabic as the raw material Extract arabinose.

After xylose is crystallized from the mixed sugars obtained by hydrolysis of hemicellulose, the remaining mixed sugars mainly contain xylose, arabinose, glucose and galactose, among which xylose and arabinose have the highest content. Six-carbon sugars such as glucose and galactose can be removed by fermentation, but xylose and arabinose are difficult to separate by fermentation. Therefore, the separation of xylose and arabinose is the key point of the present invention. According to common knowledge in this field, monosaccharides are generally difficult to dissolve in organic solvents, but xylose can be dissolved in hot ethanol and pyridine, and arabinose can be dissolved in glycerin, but it is also difficult to realize xylose and arabinose by using these common knowledge. separation.

In addition, under normal circumstances, the content of xylose in mixed sugars obtained from hemicellulose hydrolysis is at least 1.5 times greater than that of arabinose. Therefore, the mixed sugars obtained by hydrolyzing hemicellulose cannot be separated from arabinose only through general dissolution and crystallization. .

The applicant's research found that when xylose and arabinose coexist, their dissolution and crystallization properties after cooling in hot water or hot organic solvent aqueous solution are very different from those when they exist alone. In organic solvents, the solubility of xylose is greater than that of arabinose, but when xylose and arabinose coexist in hot organic solvent aqueous solution, as the water content in the solution increases, the solubility of arabinose and xylose Solubility increases, but the degree of increase in the solubility of arabinose is greater than that of xylose until the solubility of the two is close to each other; Since the degree of decrease in the solubility of arabinose is greater than that of xylose, a crystal with a ratio of xylose content to arabinose content less than or approximately equal to 1:1 can be obtained; The solubility of arabinose in organic solvents is greater than that of arabinose, so that xylose can be completely dissolved and arabinose can only be partially dissolved, so that arabinose in the form of insoluble matter can be separated. In addition, in water, the solubility of arabinose is greater than that of xylose. Therefore, water can also be used as a solvent to prepare a hot mixed sugar solution in which both xylose and arabinose are in a saturated state, and then crystallize by cooling to obtain the xylose content and Crystals with a ratio of arabinose content less than or approximately equal to 1:1.

According to the above findings, the mixed sugar obtained by hydrolysis of hemicellulose is used as the initial sugar, mixed with water or the first organic solvent aqueous solution and the initial sugar, wherein the water content in the organic solvent aqueous solution is such that the ratio of xylose content to arabinose content is less than or Approximately equal to the required water content of crystal a of 1:1, the water content can be selected between 0% to 100% according to different organic solvents, at this time, adjust the consumption of water or the first aqueous solution of organic solvent, and heat to make the Arabidopsis The sugar is completely dissolved or nearly completely dissolved, while part of the xylose is dissolved in the solution, and the other part is in the form of insoluble matter to obtain a mixture I; solid and liquid are separated to obtain crude xylose and sugar solution a; sugar solution a is cooled After crystallization, crystallization a and crystallization mother liquor a are obtained, wherein in crystallization a, the ratio of xylose content to arabinose content is less than or approximately equal to 1:1, that is, the mixed sugar is dissolved with hot water or hot first organic solvent aqueous solution. One purpose is to separate crude xylose by using the property that the solubility of xylose and arabinose in the solvent tends to be close or that the solubility of xylose is less than that of arabinose; Crystal a with a ratio less than or approximately equal to 1:1. And crystallization a will be used as the initial mixed sugar of next separation process; crystallization a is added in the second organic solvent of heat or the second organic solvent aqueous solution, the solubility of xylose in the second organic solvent or the second organic solvent aqueous solution Greater than the solubility of arabinose in the second organic solvent or the second aqueous organic solvent solution, adjust the amount of the second organic solvent or the second organic solvent aqueous solution, so that xylose is completely dissolved or nearly completely dissolved, and arabinose is partly dissolved in the solvent, and the other part exists in the form of insoluble matter to obtain mixture II; solid and liquid are separated to obtain crude arabinose and sugar solution b; sugar solution b is cooled and crystallized to obtain crystal b and crystal mother liquor b; Crystal b is the initial sugar, repeating the above steps can completely separate the xylose and arabinose in the mixed sugar obtained from the hydrolysis of hemicellulose; the obtained crude xylose and crude arabinose can be recrystallized to obtain pure xylose and pure of arabinose.

Of course, when dissolving the initial sugar with hot water or the hot first organic solvent aqueous solution, it may also occur that when the arabinose is just completely dissolved, the xylose is also completely dissolved. At this time, the initial sugar should first be mixed with the hot first Two organic solvents or a second organic solvent aqueous solution are mixed to completely dissolve xylose or nearly completely dissolve, while a part of arabinose dissolves in the solvent, and the other part exists in the form of insoluble matter, thereby obtaining the insoluble matter through solid-liquid separation Crude arabinose.

Preferably, the reuse of the crystallization mother liquor a can increase the amount of arabinose dissolved by a unit solvent, that is, the amount of solvent used can be reduced, thereby speeding up the separation speed; similarly, the reuse of the crystallization mother liquor b can increase the dissolution of xylose by a unit solvent The amount, that is, the amount of solvent can be reduced, thereby speeding up the separation speed.

Similarly, gum arabic hydrolyzate contains three monosaccharides, namely galactose, arabinose and rhamnose, of which galactose can be removed by fermentation, and the separation of arabinose and rhamnose is also the key to extract arabinose. The applicant has found that when rhamnose and arabinose coexist in hot water or an organic solvent, they have the same solubility and crystallization characteristics as xylose and arabinose when they coexist in hot water or an organic solvent. Therefore, it can Rhamnose and arabinose were separated using the same method used to separate xylose and arabinose.

The method for extracting arabinose from the mixed sugar containing arabinose and xylose or rhamnose described in the present invention is only through the extraction of the mixed sugar containing arabinose and xylose or rhamnose in organic solvents with different water contents The dissolution and crystallization process realizes the complete separation of xylose or rhamnose and arabinose, which eliminates the dependence on chromatographic separation methods and lays the foundation for large-scale preparation of arabinose.

Detailed ways

The present invention will be further illustrated and described below in conjunction with specific embodiments.

Example 1

Dilute the xylose mother liquor after crystallizing xylose from the mixed sugars obtained by hydrolysis of hemicellulose, and then add Saccharomyces cerevisiae for fermentation until the glucose and galactose are basically utilized, and the yeast cells are separated by centrifugation, and the supernatant is reduced at 70°C. Pressure distillation, concentration to sugar concentration of about 80%, cooling and crystallization, centrifugation to separate the crystals, and the crystallized mother liquor to repeat the process of vacuum distillation-cooling crystallization-separation and crystallization, and finally crystallize the non-fermentable monosaccharides in the xylose mother liquor Come out, this crystallization contains xylose and arabinose, wherein the xylose content is about 1.6 times of arabinose, as the initial sugar of this embodiment and embodiment 2, 3, 4, 5.

Add 0.86 g of the above-mentioned initial sugar and 0.30 g of 60% ethanol to the test tube, and keep warm in a water bath at 70°C for 1 hour, and the arabinose in the initial sugar is completely dissolved; under the warm state, the solid and liquid are separated to obtain sugar solution a and insoluble matter, insoluble matter For crude xylose, wash the crude xylose twice with a small amount of cold 90% ethanol and save it for later use; the sugar solution a is placed at room temperature for 36 hours to crystallize, and the solid and liquid are separated to obtain crystal a and supernatant, wherein crystal a In the method, the content of xylose is 0.5 times of that of arabinose, and the crystal a is washed twice with a small amount of cold 90% ethanol; 1.0 g of crystal a is added to 1.8 g of 90% ethanol, kept in a water bath at 70°C for 1 hour, and the wood The sugar is completely dissolved, and the arabinose is only partially dissolved; under the condition of heat preservation, the solid and liquid are separated to obtain the sugar solution b and the insoluble matter. Place the sugar solution b at room temperature for 36 hours to crystallize, separate solid and liquid to obtain crystal b and supernatant, and wash crystal b twice with a small amount of cold 90% ethanol; repeat the above separation process with crystal b, thereby continuously removing the initial Sugar is separated into crude xylose and crude arabinose; crude xylose and crude arabinose are respectively redissolved in 90% ethanol at 80°C to form a saturated solution, and then placed at room temperature for 36 hours for crystallization, crystallization with cold 90% ethanol Wash twice and dry to get pure xylose and arabinose.

Example 2

Add 1.3 g of the above-mentioned initial sugar and 0.4 g of water into the test tube, and keep warm in a water bath at 70°C for 0.5 hours. The arabinose in the initial sugar is completely dissolved, and the solid and liquid are separated to obtain sugar solution a and insoluble matter. The insoluble matter is crude xylose. Wash the crude xylose twice with a small amount of cold 90% ethanol and save it for later use; the sugar solution a is placed at room temperature for 72 hours to crystallize, and the solid and liquid are separated by centrifugation to obtain crystal a and supernatant, wherein, in crystal a, xylose The sugar content and the arabinose content are close to 1:1, and the crystal a is washed twice with a small amount of cold 90% ethanol; 1.0 g of crystal a is added to 2.8 g of 90% ethanol, kept in a water bath at 70°C for 1 hour, and the xylose in it is completely Dissolved, only a part of the arabinose was dissolved; in the heat preservation state, the solid and liquid were separated to obtain sugar solution b and insoluble matter, the insoluble matter was crude arabinose, washed with a small amount of cold 90% ethanol twice and stored for later use; Place solution b at room temperature for 36 hours to crystallize, separate solid and liquid to obtain crystal b and supernatant, wash crystal b twice with a small amount of cold 90% ethanol; repeat the above separation process with crystal b, so as to continuously separate the initial sugar into crude xylose and crude arabinose; crude xylose and crude arabinose were respectively redissolved in 90% isopropanol at 80°C to form a saturated solution, and then placed at room temperature for 24 hours for crystallization, crystallization was carried out with cold 90% isopropanol Washed twice with propanol and dried to obtain pure xylose and arabinose.

Example 3

Add 0.52 g of the above-mentioned initial sugar into the test tube, gradually add 70% acetic acid, keep warm in a 70°C water bath, the addition of 70% acetic acid makes the arabinose completely dissolved, and the solid and liquid are separated to obtain sugar solution a and insoluble matter, the insoluble matter is crude Xylose, wash the crude xylose twice with a small amount of cold 90% acetic acid and save it for later use. Add the crystallization accelerator butanone to the sugar solution a until it becomes turbid, place it at room temperature for 48 hours to crystallize, and separate the solid and liquid to obtain crystal a and In the supernatant, crystal a is washed twice with a small amount of cold 90% acetic acid to obtain crystal a, wherein, in crystal a, the content of xylose is 0.5 times that of arabinose; take 1.0 g of crystal a and gradually add 90% acetic acid , keep warm in a water bath at 70°C, add 90% acetic acid to dissolve xylose completely, separate solid and liquid to obtain sugar solution b and insoluble matter, the insoluble matter is crude arabinose, wash the crude arabinose with a small amount of cold 90% acetic acid After 2 times, save it for later use; place sugar solution b at room temperature for 48 hours for crystallization, separate solid and liquid to obtain crystal b and supernatant, wash crystal b twice with a small amount of cold 90% acetic acid; take crystal b and repeat the above separation process , so that the mixed sugar is continuously separated into crude xylose and crude arabinose; crude xylose and crude arabinose are respectively re-dissolved in 90% ethanol at 80°C to form a saturated solution, and then placed at room temperature for 48 hours for crystallization. Washed twice with cold 90% ethanol and dried to obtain pure xylose and arabinose.

Example 4

Add 0.52 grams of the above-mentioned initial sugar and 0.50 grams of 50% acetone into the test tube, and keep warm in a water bath at 50° C. for 1 hour. The arabinose therein just dissolves completely, and the sugar solution a and insoluble matter are obtained by solid-liquid separation. The insoluble matter is crude xylose. Wash the crude xylose twice with a small amount of cold 90% acetone and save it for later use; add 1 times the amount of absolute ethanol as a crystallization accelerator to the sugar solution a, place it at room temperature for 36 hours to crystallize, and separate solid and liquid to obtain crystal a and The supernatant, wherein, in crystal a, the xylose content is 1.1 times that of arabinose, was washed twice with a small amount of cold 90% acetone; 1.0 g of crystal a was added to 2.9 g of 90% ethanol, and placed in a water bath at 70°C Keep warm for 1 hour, the xylose in it just dissolves completely, under the warm state, the solid and liquid are separated to obtain sugar solution b and insoluble matter, the insoluble matter is crude arabinose, wash the crude arabinose twice with a small amount of cold 90% ethanol Store for later use; place the sugar solution b at room temperature for 36 hours for crystallization, separate solid and liquid to obtain crystal b and supernatant, wash crystal b twice with a small amount of cold 90% ethanol; take crystal b and repeat the above separation process, thereby continuously The mixed sugar is separated into crude xylose and crude arabinose; crude xylose and crude arabinose are respectively redissolved in 90% ethanol at 80°C to form a saturated solution, and then placed at room temperature for 36 hours for crystallization, crystallization with cold 90 Washed twice with % ethanol and dried to obtain pure xylose and arabinose.

Example 5

Add 0.52 g of the above-mentioned initial sugar into the test tube, add 0.44 g of 50% pyridine aqueous solution, and keep warm in a water bath at 70°C, so that the arabinose just dissolves completely. For xylose, wash the crude xylose twice with a small amount of cold 90% ethanol and save it for later use; the sugar solution a is placed at room temperature for 36 hours to crystallize, and the solid and liquid are separated to obtain crystal a and supernatant, wherein, in crystal a, The content of xylose is 1.2 times of that of arabinose; crystal a is washed twice with a small amount of cold 99.5% pyridine; 1.0 g of crystal a is added to 3.0 g of 99.5% pyridine, kept in a water bath at 60°C, xylose is just completely dissolved, solid , liquid separation to obtain sugar solution b and insoluble matter, the insoluble matter is crude arabinose, the crude arabinose is washed twice with a small amount of cold 99.5% pyridine and stored for later use; sugar solution b is distilled to dryness under reduced pressure at 70°C to obtain crystal b ; crystallization b repeats the above separation process, thereby continuously separating the initial sugar into crude xylose and crude arabinose; crude xylose and crude arabinose are respectively re-dissolved in 90% ethanol at 80°C to form a saturated solution, and then placed at room temperature Carry out crystallization for 48 hours, wash crystallization twice with cold 90% ethanol, and obtain pure xylose and arabinose after drying.

Example 6

Gum Arabic is hydrolyzed with dilute sulfuric acid to obtain a hydrolyzate, and the acid is extracted with diisooctylamine solution to obtain a hydrolyzate with a pH of 5.6, then fermented with Saccharomyces cerevisiae to remove galactose, the fermentation liquid is centrifuged to remove yeast cells, and then reduced pressure at 70°C Distill to a sugar concentration of about 80%, crystallize after cooling and dry the crystals, and continue to reuse the crystallization mother liquor to crystallize all the mixed sugars. The content of arabinose in the crystals is about twice that of rhamnose, that is, rhamnose is 0.5 times of arabinose, as the initial sugar of this embodiment.

Mix the initial sugar with 90% ethanol, heat to 70°C and stir to dissolve part of the sugar. The amount of 90% ethanol added is the amount required for the rhamnose in the mixed sugar to be completely dissolved, and a mixture II is obtained, in which part of the arabinose is insoluble It exists in the form of substance, and then the solid-liquid separation is carried out to obtain the insoluble crude arabinose and the sugar solution b; the sugar solution b is distilled to dryness under reduced pressure at 70°C to obtain the crystal b, and the rhamnose content in the crystal b is about 2.5 times the content of arabinose; crystal b is mixed with 90% isopropanol, heated to 70°C and stirred to dissolve part of the sugar, and the amount of 90% isopropanol added is the amount required for the complete dissolution of arabinose in the mixed sugar , to obtain mixture I, wherein part of the rhamnose exists in the form of insoluble matter, and then carry out solid-liquid separation to obtain insoluble matter thick rhamnose and sugar solution a; sugar solution a is cooled to room temperature and placed for 24 hours for crystallization to obtain Crystallization a and crystallization mother liquor a, and drying of crystallization a, the content of arabinose in crystallization a is about 1.2 times of rhamnose content, that is, rhamnose is about 0.8 times of arabinose, that is, the content of arabinose is greater than that of rhamnose Li sugar content.

Crystal a was re-mixed with 90% ethanol, heated to 70°C and stirred to dissolve part of the sugar. The amount of 90% ethanol added was the amount required for the rhamnose in crystal a to be completely dissolved to obtain mixture II, in which part of the arabinose was The insoluble matter exists in the form of solid-liquid separation, and the insoluble matter crude arabinose and sugar solution b are obtained; the sugar solution b is distilled to dryness under reduced pressure at 70°C to obtain crystal b, and the rhamnose content in crystal b is about The content of arabinose is 2.5 times; crystal b is mixed with crystallization mother liquor a, heated to 70°C and stirred to dissolve part of the sugar, and the amount of crystallization mother liquor a is just the amount required for the complete dissolution of arabinose in the mixed sugar to obtain mixture I , where part of the rhamnose exists in the form of insoluble matter, and then solid-liquid separation is carried out to obtain the insoluble matter thick rhamnose and sugar solution a; the sugar solution a is cooled to room temperature and placed for 24 hours for crystallization, and crystallization a and crystallization Mother liquor a, and drying crystal a, the content of arabinose in crystal a is about 1.3 times the rhamnose content, that is, the rhamnose is about 0.8 times that of arabinose, that is, the arabinose content is greater than the rhamnose content. Repeat the above steps until the arabinose and rhamnose are completely separated.

Recrystallize crude arabinose and crude rhamnose in 90% ethanol to obtain pure arabinose and pure rhamnose.

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, all equivalent changes or modifications made with the features and principles described in the claims of the present invention should be included in the present invention. within the scope of the claims.

Claims (19)

1. a method of extracting pectinose from the mixing sugar that contains pectinose wherein, also contains wood sugar or rhamnosyl in the mixing sugar, it is characterized in that this method may further comprise the steps:

(1) gets the above-mentioned mixing sugar that contains pectinose and be initial sugar;

(2) with the aqueous solution of initial sugar with the water or first organic solvent, heating makes initial sugar moieties dissolving, the water content of the aqueous solution of described first organic solvent for the ratio of the ratio that obtains wood sugar content and pectinose content or rhamnosyl content and pectinose content less than or approximate 1: 1 the needed water content of crystallization a, the consumption of the aqueous solution of described water or described first organic solvent is about under this heating condition that pectinose dissolves needed amount fully in the initial sugar, mixture I;

(3) mixture I solid, liquid is separated, obtain sugar soln a and thick wood sugar, or obtain sugar soln a and thick rhamnosyl;

(4) sugar soln a cooling post crystallization separates obtaining crystallization a and crystalline mother solution a, wherein, among the described crystallization a, the ratio of the ratio of wood sugar content and pectinose content or rhamnosyl content and pectinose content less than or approximate 1: 1;

(5) with the aqueous solution of crystallization a and second organic solvent or second organic solvent, heating is partly dissolved crystallization a, the consumption of the aqueous solution of described second organic solvent or described second organic solvent is about under this heating condition among the crystallization a wood sugar or rhamnosyl dissolves needed amount fully, mixtures II;

(6) the mixtures II solid, liquid is separated, obtain sugar soln b and thick pectinose.

2. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 1 is characterized in that, and is further comprising the steps of:

(7) with sugar soln b cooling post crystallization, separate obtaining crystallization b and crystalline mother solution b;

(8) serve as initial sugar with crystallization b, repeat above-mentioned (2)～(7) step, the pectinose in the mixing sugar that will contain pectinose all extracts.

3. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 1 or 2 is characterized in that, step (3) is separated mixture I solid, liquid and/or step (6) is separated in the mixtures II solid, liquid under the keeping warm mode and carries out.

4. the method for from the mixing sugar that contains pectinose, extracting pectinose as claimed in claim 1 or 2, it is characterized in that, during crystallization, add the third organic solvent as crystallization promoter in described sugar soln a or described sugar soln b, described the third organic solvent is selected from alcohol, ether and ketone.

5. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 1 or 2 is characterized in that described crystalline mother solution a reuse is as the aqueous solution of described water of step (2) or described first organic solvent; Crystalline mother solution b reuse is as the aqueous solution of described second organic solvent of step (5) or described second organic solvent.

6. the method for from the mixing sugar that contains pectinose, extracting pectinose as claimed in claim 1 or 2, it is characterized in that, when described crystalline mother solution a contains described crystallization promoter, remove behind the crystallization promoter reuse again as the aqueous solution of described water of step (2) or described first organic solvent, when described crystalline mother solution b contains described crystallization promoter, remove behind the crystallization promoter reuse again as the aqueous solution of described second organic solvent of step (5) or described second organic solvent.

7. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 1 or 2 is characterized in that, during crystallization, described sugar soln a or described sugar soln b evaporation is removed part or all of solvent.

8. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 1 or 2 is characterized in that, the described mixing sugar that contains pectinose is the mixture of monosaccharides with the hemicellulose hydrolysate preparation.

9. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 1 or 2 is characterized in that, the mixture of monosaccharides that the described mixing sugar that contains pectinose prepares for the xylose mother liquid that goes out with the hemicellulose hydrolysate crystallization behind the wood sugar.

10. the method for from the mixing sugar that contains pectinose, extracting pectinose as claimed in claim 1 or 2, it is characterized in that the described mixing sugar that contains pectinose is removed the mixture of monosaccharides for preparing behind the glucose by fermentation for the xylose mother liquid that goes out with the hemicellulose hydrolysate crystallization behind the wood sugar.

11. the method for from the mixing sugar that contains pectinose, extracting pectinose as claimed in claim 1 or 2, it is characterized in that the described mixing sugar that contains pectinose is removed the mixture of monosaccharides for preparing after glucose and the semi-lactosi by fermentation for the xylose mother liquid that goes out with the hemicellulose hydrolysate crystallization behind the wood sugar.

12. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 1 or 2 is characterized in that, the described mixture of monosaccharides of mixing sugar for preparing after semi-lactosi is removed in fermentation with the gum arabic hydrolyzed solution that contains pectinose.

13. the method for from the mixing sugar that contains pectinose, extracting pectinose as claimed in claim 1 or 2, it is characterized in that, described first organic solvent and described second organic solvent all are selected from alcohol, ketone, carboxylic acid, nitrogenous organic solvent, the polyfunctional compound of several functional groups in hydroxyl, ketone group, the carboxyl and several mixture in them.

14. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 13 is characterized in that described first organic solvent and/or described second organic solvent also contain other organic solvents.

15. the method for from the mixing sugar that contains pectinose, extracting pectinose as claimed in claim 13, it is characterized in that described alcohol is selected from the alcohol of C1～C3, described ketone is selected from acetone and butanone, described carboxylic acid is selected from the carboxylic acid of C1～C4, and described nitrogenous organic solvent is selected from acetonitrile and pyridine.

16. the method for from the mixing sugar that contains pectinose, extracting pectinose as claimed in claim 1 or 2, it is characterized in that, before the aqueous solution of described crystallization a and described second organic solvent or described second organic solvent earlier with the solution washing of cold organic solvent or cold organic solvent; Before the aqueous solution of described crystallization b and described water or described first organic solvent earlier with the solution washing of cold organic solvent or cold organic solvent.

17. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 1 or 2 is characterized in that, carries out drying earlier before the aqueous solution of described crystallization a and described second organic solvent or described second organic solvent; Carry out drying before the aqueous solution of described crystallization b and described water or described first organic solvent earlier.

18. the method for extracting pectinose from the mixing sugar that contains pectinose as claimed in claim 1 or 2 is characterized in that, the thick pectinose of gained, thick wood sugar or thick rhamnosyl obtain pure pectinose, pure wood sugar or pure rhamnosyl through recrystallization.

19. the method for from the mixing sugar that contains pectinose, extracting pectinose as claimed in claim 1, it is characterized in that, in step (2), when the pectinose in the initial sugar dissolves fully, wood sugar or rhamnosyl be dissolving fully also, then begins to extract pectinose from initial sugar from step (5).