1 DESCRIPTION METHOD OF PRODUCING SACCHARIDE COMPOSITION STARTING WITH BIOMASS TECHNICAL FIELD [0001] The present invention relates to a method of producing a saccharide composition containing an oligosaccharide, glucose, and the like, by subjecting a biomass as a raw material to acid-treatment. Priority is claimed on Japanese Patent Application No. 2005-250860, filed on August 31, 2005, the content of which is incorporated herein by reference. BACKGROUND ART [0002] Reduction targets of carbon dioxide emissions have been determined in the Kyoto Protocol, and the Kyoto Protocol has been ratified as a global warming countermeasure. Japan is required to reduce its carbon dioxide emissions to 6% below 1990 levels. In order to reduce the carbon dioxide emissions, it is useful to utilize a biomass energy instead of a fossil fuel energy. Against such a background, the alcohol business in Japan developed a gasoline containing 3% alcohol which has been commercialized since 2006. If calculated in terms of the actual use amount of gasoline in 2000, approximately 1,800,000 kiloliters of alcohol is estimated to be required when alcohol is formulated in all gasoline. [0003] A wood biomass which is expected to be supplied in the greatest amount as a biomass has a physically and chemically strong structure in which a crystal structure of a cellulose fiber forms a complex with a lignin. The cellulose is a polymer of 1-4 linked D-glucose and composed of a crystalline region and a non-crystalline region. Other 2 polysaccharide components are hemicelluloses and composed of various monosaccharides such as xylose, arabinose, mannose, or the like. The lignin is an aromatic polymer containing phenylpropane as the basic unit thereof, and the structure thereof is different from that of a saccharide composition such as cellulose or hemicellulose. From the chemical standpoint, wood is composed of approximately 50% of cellulose and approximately 20 to 30% of hemicellulose as main components thereof, and several percent of accessory components (Non-Patent Document 1). [0004] Most of wood biomasses such as timber from forest-thinning, building waste lumber, industrial waste, domestic waste, or agricultural waste, or waste having a high content of the wood biomass are treated by reclamation or incineration, the current treating method is approaching its limits in that disposal stations are being closed down and incineration produces dioxine. Since the wood biomass may be a useful biochemical raw material or an energy source, development of technologies for extracting useful components while reducing the amount of waste has been desired as a countermeasure against environmental issues and energy issues. [0005] Conversion from wood biomass to highly-exothermic fuel has conventionally been tried by various techniques, and conversion to liquid fuel such as, for example, methane, butanol, ethanol, or methanol has conventionally been tried many times, in particular. Although one reason for this may be that the liquid fuel is superior to a bulky solid fuel in terms of transportation and storage, the greater reason for this is that the calorific value per unit mass is significantly improved in comparison with wood materials. [0006] Although thermal decomposition, gasification, anaerobic fermentation, and the like, have been broadly performed for biomass conversion as shown in many documents (Non-Patent Documents 2 to 5), a method for obtaining an ethanol by fermentation performed after obtaining monosaccharide by acid- or enzyme-hydrolysis has been 3 broadly researched. Since the enzyme-hydrolysis reaction requires that enzyme molecules enter voids in a target biomass, pretreating is required to be performed in accordance with a chemical, physical, or microbiological method, which is an obstacle to practical application from the standpoint of cost. [0007] On the other hand, a method in which main components, polysaccharides, such as cellulose or hemicellulose, are hydrolyzed to monosaccharides to separate from aromatic polymer lignin has been researched as a method for acid saccharification by acid hydrolysis, for a number of years, as shown in the above-mentioned documents. Saccharification methods conventionally proposed are roughly divided into a dilute acid method and a concentrated acid method depending on the concentration of an acid used as a catalyst. The dilute acid method is a method for saccharification by performing reaction at 120*C, occasionally at approximately 240'C, using several % of sulfuric acid. Although the dilute acid method has advantages in that an acid is easily recovered and reused and an apparatus exhibits low corrosiveness, the dilute acid method has disadvantages in that the reaction is required to be performed under high temperature and high pressure conditions, and the glucose yield is low. The concentrated acid method is a method in which approximately 70% of sulfuric acid or approximately 40% of hydrochloric acid is used, and has advantages in that reaction can be performed at a lower temperature than the dilute acid method and the yield is high, while it has disadvantages in that an apparatus exhibits high corrosiveness and the recovery of an acid is difficult. [0008] All of the above-mentioned methods are methods for effectively yielding a liquid to be subjected to the post ethanol fermentation process, and the following techniques have been proposed as further improved methods. [0009] (1) An amorphous cellulose or cellooligosaccharide obtained by vigorously stirring at a temperature of 30 to 60*C a cellulose material dissolved and/or swollen in 70% by 4 mass or more of a phosphoric acid is decomposed by cellulase (Patent Document 1). (2) A cellulose material and a hemicellulose material are mixed with approximately 25 to 90% by mass of an acid solution at 35 to 80*C to gelatinize the mixture, and then the resultant is diluted so that the acid concentration thereof is 20 to 30% by mass, followed by heating at 80 to I 00*C to accelerate hydrolysis (Patent Document 2). [0010] (3) A cellulose material is dissolved in a chelating metal caustic swelling solvent such as cadoxen and then hydrolyzed using a diluted sulfuric acid (Patent Document 3). (4) A cellulose material is treated with a liquid mixture composed of a concentrated hydrochloric acid and a concentrated sulfuric acid (Patent Document 4). (5) Treatment with a mineral acid and an acetic acid is performed for acetylation in order to destroy the fine structure (Patent Document 5). [0011] However, it has been described that a carbohydrate solution treated by the above mentioned methods is a mixture of constituent sugars of the hemicellulose and cellulose, and some sugars such as xylose significantly inhibit the fermentation reaction in the subsequent fermentation process. Accordingly, various proposals have been made to purify a carbon source required for fermentation from such a saccharified liquid. Moreover, the method for saccharification with an acid causes problems in terms of production cost in that vigorous stirring under high temperature and high pressure conditions is required to be performed. In order to streamline the subsequent fermentation process, almost all in the saccharified liquid is decomposed to be monosaccharide, and the recovery of oligosaccharide of which physiological actions such as regulation of intestinal function have recently attracted attention is not focused on, and only improvement of the glucose yield achieved by repeatedly subjecting the oligosaccharide to acid- or enzyme-hydrolysis has attracted attention. [0012] The oligosaccharide is a bonded body of several monosaccharides such as 5 glucose or fructose, and examples thereof include fructooligosaccharide, soybean oligosaccharide, galactooligosaccharide, xylooligosaccharide, agarooligosaccharide, and the like. Such oligosaccharides are considered to act as an anticaries sweetener, regulate intestinal function by selectively promoting proliferation of enterobacteria, and exhibit an excretory effect of excess intestinal cholesterol or bile acid in the same way as that of dietary fiber. Thus, the oligosaccharide is a useful sugar to be formulated in a lactic acid beverage or food certified as a specified health food and is widely used as an emulsifier, moisturizing agent, or the like, in the fields of medicine, sanitation, or the like. [0013] The following methods have been proposed to prepare oligosaccharide. (1) A natural lignocellulose material is pulped to obtain a pulp, the pulp is partially hydrolyzed with cellulase to obtain a cellooligosaccharide, while continuously treating the liquid reaction mixture with an ultrafilter membrane to adjust the polymerization degree of the oligosaccharide (Patent Document 6). (2) A xylan raw material is decomposed by treating it with hemicellulase under particular reaction conditions to obtain xylobiose with a high concentration while suppressing the yield of xylose (Patent Document 7). [0014] (3) Inulobiose is reacted in an aqueous medium in the presence of an enzyme source having an ability of hydrolyzing levan and the inulobiose to recover an oligosaccharide produced in an aqueous medium (Patent Document 8). (4) A xylan-containing natural product is finely pulverized, steamed, washed with water, extracted with water, treated with ozone, treated with an ion-exchange resin, concentrated, and dried, to obtain an oligosaccharide (Patent Document 9). (5) A pulp for papermaking is treated with hemicellulase, and then the resultant liquid is concentrated by a membrane filtration method, and hydrolyzed with acid to obtain an oligosaccharide (Patent Document 10). [0015] 6 In the above-mentioned methods (1) to (3) and (5), each enzyme is used in the process of preparing the oligosaccharide or in the pre-treatment process. The enzyme with a high substrate-specificity is used to obtain a pure oligosaccharide. However, the high cost of the enzyme hinders practical application thereof. In the method (4), the treatment is required to be performed under high-temperature and high-pressure and also ozone-treatment increases the cost. [Patent Document 1] Japanese Patent Publication No. 3016419 [Patent Document 2] Published Japanese translation No. H 11-506934 of PCT International Publication [Patent Document 3] Japanese Unexamined Patent Application, First Publication No. S54-160755 [Patent Document 4] Japanese Examined Patent Application, Second Publication No. S57-53801 [Patent Document 5] Japanese Examined Patent Application, Second Publication No. S59-53040 [Patent Document 6] Japanese Examined Patent Application, Second Publication No. H8-2312 [Patent Document 7] Japanese Unexamined Patent Application, First Publication No. S62-155095 [Patent Document 8] Japanese Unexamined Patent Application, First Publication No. H8-283284 [Patent Document 9] Japanese Examined Patent Application, Second Publication No. H7-055957 [Patent Document 10] Japanese Unexamined Patent Application, First Publication No. H12-333692 [Non-Patent Document 1] Takafusa Haraguchi, et al., "Wood chemistry", pages 4 to 5, published by BUNEIDO PUBLISHING CO., LTD., in 1985. [Non-Patent Document 2] "Technologies for utilization of wood biomass" edited by The Japan Wood Research Society, pages 19 to 61, published by BUNEIDO PUBLISHING 7 Co., LTD., in July 1991. [Non-Patent Document 3] Hideaki Yukawa, et al., "Recent advances in technologies for utilization of biomass energy", Chapter Il-1 organized by topics, published by CMC Publishing CO., L.D., in August 2001. [Non-Patent Document 4] Gyosuke Meshitsuka, et al., "Recent advances in technologies for wood chemicals", pages 6 to 34, published by CMC Publishing CO., LTD., in October 2001. [Non-Patent Document 5] Funaoka, et al., "Advanced Technologies for Woody Organic Resources" Chapter 5-2, published by CMC Publishing CO., LTD., in January 2005. A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission or a suggestion that that document or matter was, known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims. Throughout the description and claims of the specification, the word "comprise" and variations of the word, such as "comprising" and "comprises", is not intended to exclude other additives, components, integers or steps. DISCLOSURE OF THE INVENTION [Problems to be Solved by the Invention] [0016] The inventors of the present invention focused on biomass, particularly, focused on acid-treatment of wood biomass in terms of hemicellulose oligosaccharide, cellulose oligosaccharide, and glucose, and conducted thorough research. As a result, the inventors found that the three saccharide compositions can be separated easily without utilizing an enzyme reaction. Thus, it is one aspect of the present invention to easily separate and recover saccharide compositions contained in a wood biomass. In addition, it is another aspect of the present invention to enhance the efficiency of ethanol fermentation performed at the subsequent stage by separating the hemicellulose saccharide composition from the cellulose saccharide composition. [Means for Solving the Problems] [0017] In order to achieve the aspects, the present invention encompasses the following, aspects. (1) A method of producing plural kinds of saccharide compositions, including the steps of: treating a solid biomass with at least two kinds of acid-treatment liquids having 8 different acid concentrations; separating a liquid reaction mixture obtained in each acid-treatment step into a supernatant and solid matter; and subjecting the separated solid matter to a successive acid-treatment step and repeating this process so as to separate and recover different kinds of saccharide in each of the acid-treatment step. [0018] (2) The method of producing plural kinds of saccharide compositions according to the item (1), characterized in that the solid biomass contains a wood biomass. [0019] (3) The method of producing plural kinds of saccharide compositions according to the item (1) or (2), characterized in that the solid biomass is pulverized into fine particles with a size that allows the solid biomass to pass through a sieve having 10 mm openings. [0020] (4) The method of producing plural kinds of saccharide compositions according to any one of the items (1) to (3), characterized in that the acid-treatment is performed at 35*C or lower. [0021] (5) The method of producing plural kinds of saccharide compositions according to any one of the items (1) to (4), characterized in that the acid-treatment liquid used in each acid-treatment step contains at least one acid selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid. [0022] (6) The method of producing plural kinds of saccharide compositions according to any one of the items (1) to (5), characterized in that in one acid-treatment step of the acid-treatment steps, a hemicellulose oligosaccharide is separated and recovered as the supernatant, and the acid-treatment liquid used has an acid concentration of 55 to 63% by mass. [0023] (7) The method of producing plural kinds of saccharide compositions according to any one of the items (1) to (6), characterized in that in one acid-treatment step of the 9 acid-treatment steps, a cellulose oligosaccharide is separated and recovered as the supernatant, and the acid-treatment liquid used has an acid concentration of 64 to 70% by mass. [0024] (8) The method of producing plural kinds of saccharide compositions according to the item (7), characterized in that in the one acid-treatment step of the acid-treatment steps, the cellulose oligosaccharide separated and recovered as the supernatant is agglomerated by decreasing the acid concentration of the separated supernatant from 64-70% by mass to 30-63% by mass. [0025] (9) The method of producing plural kinds of saccharide compositions according to any one of the items (1) to (8), characterized in that saccharide composition is isolated from the supernatant separated in each acid-treatment step using a cellulose base material as a filter. [0026] (10) The method of producing plural kinds of saccharide compositions according to any one of the items (7) to (9), characterized by further comprising a step in which the cellulose oligosaccharide obtained in the acid-treatment step is treated with an acid or an enzyme to invert the cellulose oligosaccharide to monosaccharides containing a glucose as the main component thereof. [0027] (11) The method of producing plural kinds of saccharide compositions according to any one of the items (1) to (10), characterized in that in a first acid-treatment step of treating a solid biomass with at least two kinds of acid-treatment liquids having different acid concentrations, a hemicellulose oligosaccharide is separated and recovered as the supernatant, and in a second acid-treatment step thereof, solid matter separated from the supernatant in the first acid-treatment step is treated with an acid-treatment liquid to separate and recover a cellulose oligosaccharide as the supernatant. [0028] 10 (12) The method of producing plural kinds of saccharide compositions according to any one of the items (1) to (11), characterized in that the acid-treatment step in which the cellulose oligosaccharide is separated and recovered, includes a step of filtering the supernatant containing the cellulose oligosaccharide with a filter produced from a cellulose base material to separate a filtrate containing a cellulose oligosaccharide component with a low-polymerization degree from a cellulose oligosaccharide component with a relatively high-polymerization degree. [0029] (13) The method of producing plural kinds of saccharide composition according to the item (12), characterized in that the acid concentration of the filtrate containing a cellulose oligosaccharide component with a low-polymerization degree is decreased to 30-63% by mass to agglomerate the cellulose oligosaccharide component with a low polymerization degree to invert into a cellulose oligosaccharide with a high polymerization degree. [0030] (13) The method of producing plural kinds of saccharide compositions according to any one of the items (1) to (11), characterized in that in at least one acid-treatment step of the steps of treating the solid biomass with at least two kinds of acid-treatment liquids having different acid concentrations, solid matter containing the saccharide composition to be separated is added to the separated supernatant and the mixture is subjected to the acid-treatment step. The present invention also provides a method of producing plural kinds of saccharide compositions, comprising the steps of: treating a solid biomass with at least two kinds of acid-treatment liquids having different acid concentrations; separating a liquid reaction mixture obtained in each acid-treatment step into a supernatant and solid matter; and subjecting the separated solid matter to a successive acid-treatment step and repeating this process so as to separate and recover different kinds of saccharide in each of the acid-treatment step, wherein in one acid-treatment step of the acid-treatment steps, a hemicellulose 10a oligosaccharide is separated and recovered as the supernatant and the acid treatment liquid used has an acid concentration of 55 to 63% by mass, in another acid-treatment step of the acid treatment steps, a cellulose oligosaccharide is separated and recovered as the supernatant, the acid-treatment liquid used in each acid-treatment step comprises sulfuric acid, and the acid-treatment steps are performed at normal pressures and at 35*C or lower. [Effects of the Invention] [0031] According to the present invention, saccharide compositions which may be useful biochemical raw materials or energy sources can be obtained from wood biomass such as building waste lumber, industrial waste, domestic waste, agricultural waste, (most of which has been conventionally treated by reclamation or incineration,) or lumber from thinning, or waste matter containing a high content of the wood biomass, as 11 a result of which a favorable technique as a countermeasure for environmental issues and energy issues has been provided. BRIEF DESCRIPTION OF THE DRAWINGS [0032] FIG. I shows results of ion chromatography of a hydrolysate obtained in Reference Example 2. FIG. 2 shows results of ion chromatography of a saccharide composition solution obtained in Example 1-2. FIG. 3 shows results of ion chromatography of a hydrolysate of the saccharide composition solution obtained in Example 1-2. FIG. 4 shows results of ion chromatography of a hydrolysate of a saccharide composition solution obtained in the first stage of reaction using cryptomeria. FIG. 5 shows results of ion chromatography of a hydrolysate of a saccharide composition solution obtained in the second stage of reaction using cryptomeria. FIG. 6 shows results of ion chromatography of a hydrolysate of a saccharide composition solution obtained in the first stage of reaction using Japanese cypress. FIG. 7 shows results of ion chromatography of a hydrolysate of a saccharide composition solution obtained in the second stage of reaction using Japanese cypress. FIG. 8 shows results of ion chromatography of a hydrolysate of a saccharide composition solution obtained in the first stage of reaction using quercus serrata. FIG. 9 shows results of ion chromatography of a hydrolysate of a saccharide composition solution obtained in the second stage of reaction using quercus serrata. FIG. 10 shows results of ion chromatography of a hydrolysate of a saccharide composition solution obtained in the first stage of reaction using mallee. FIG. 11 shows results of ion chromatography of a hydrolysate of a saccharide composition solution obtained in the second stage of reaction using mallee. BEST MODE FOR CARRYING OUT THE INVENTION 12 [0033] In the following, the present invention will be explained in more detail. Examples of the biomass to be treated according to the present invention include lumber from thinning, building waste lumber, wood material chip, sawdust, pruned materials, industrial or domestic waste containing wood material, agricultural waste, such as rice husk, bamboo, bagasse, straw, corncob, and the like. In addition, cellulose materials, such as waste newspaper, magazine, cardboard, waste paper, pulp, pulp sludge, cotton waste, cotton, arboreous cotton, or the like, may be treated. The above-mentioned biomass raw material may be finely pulverized before subjecting to treatment, so as to decrease the reaction time. If the biomass raw material is finely pulverized so that the pulverized biomass raw material can pass through a 10 mm-opening sieve, the reaction time is effectively decreased. It is more preferable that the biomass raw material be pulverized into particles with a particle size of 5 mm or less. In addition, it is preferable that the particle size be 10 ptm or more. [0034] According to the present invention, the biomass raw material is treated with an acid-treatment liquid containing 55 to 63% by mass of an acid to elute hemicellulose oligosaccharide. As the acid, a mineral acid, such as sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, or hydrofluoric acid, an organic acid, such as trifluoroacetic acid, or an acid-mixture thereof may be used. Among them, at least one selected from the group consisting of sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid is preferable, and sulfuric acid is more preferable. It is even more preferable that 60 to 62% by mass of sulfuric acid be formulated. The reaction of eluting hemicellulose oligosaccharide immediately occurs at normal pressures and 35*C or lower. In order to prevent the polymerization degree of oligosaccharide from decreasing, the reaction is preferably performed at 25*C or lower, and more preferably 20*C or lower. It is preferable that the reaction time be 2 to 48 hours, and more preferably 4 to 24 hours approximately. Neither heat nor pressure is required to be applied in the reaction. Unlike the conventional technique, 13 oligosaccharides are mainly produced, and even if monosaccharides are yielded, the yield thereof is extremely small. Accordingly, the yield of a furfural compound due to excess decomposition of monosaccharide and coloration due to Maillard reaction caused by monosaccharide and amino acid are suppressed. [0035] In order to recover the eluted hemicellulose oligosaccharide, an insoluble fraction is removed from the liquid reaction mixture by centrifugation to obtain a supernatant, and the supernatant is subjected to an ion-exchange resin method, a membrane concentration method, or the like. Alternatively, the eluted hemicellulose oligosaccharide can be easily separated and recovered by adsorbing the eluted hemicellulose oligosaccharide to pulp, cellulose powder, or cellulose filter. Alternatively, a method in which an insoluble fraction is removed from the liquid reaction mixture and then the acid concentration thereof is drastically decreased to agglomerate oligosaccharide may be adopted. [0036] The hemicellulose oligosaccharide compositions obtained by the above-mentioned method differ from each other in terms of the yield, structure, or component-ratio thereof depending on the kind of the biomass raw material treated. Examples of the oligosaccharide include xylooligosaccharide derived from glucuronoxylan, galactooligosaccharide derived from galactan, mannooligosaccharide derived from glucomannan, and the like. The oligosaccharide is yielded as an oligosaccharide composition composed of xylose, arabinose, galactose, rhamnose, galacturonic acid, glucuronic acid, glucose, and the like, for example. [0037] Next, the insoluble fraction is treated with an acid-treatment liquid containing 64 to 70% by mass of an acid to dissolve cellulose oligosaccharide. Examples of the acid include sulfuric acid, nitric acid, hydrochloric acid, phosphoric acid, hydrofluoric acid, trichloroacetic acid, and a mixture containing the acid as the main component thereof. Among them, at least one selected from the group consisting of sulfuric acid, nitric acid, 14 hydrochloric acid, and phosphoric acid is preferably used, and sulfuric acid is more preferably used. In particular, the use of 64 to 66% by mass of sulfuric acid is suitable to elute the cellooligosaccharide according to the present invention. The reaction of dissolving the cellulose oligosaccharide immediately occurs at normal pressures and 35*C or lower. In order to prevent the polymerization degree of oligosaccharide from decreasing, the reaction is preferably performed at 25*C or lower. The reaction of eluting the cellulose oligosaccharide is preferably performed at 0*C or higher. The reaction time thereof is preferably 1 to 48 hours, and more preferably 2 to 24 hours approximately. [0038] The cellulose oligosaccharide may be recovered in the same way as that of the hemicellulose oligosaccharide. That is, the cellulose oligosaccharide can be recovered by removing an insoluble fraction from the liquid reaction mixture by centrifugation or the like to separate a supernatant, followed by subjecting the supernatant to an ion-exchange resin method, membrane concentration method, or the like. Alternatively, the cellulose oligosaccharide can be easily separated and recovered by adsorbing the cellulose oligosaccharide to pulp, cellulose powder, or cellulose filter. Alternatively, a method in which an insoluble fraction is removed from the liquid reaction mixture containing the cellulose oligosaccharide and then the acid concentration thereof is drastically decreased to agglomerate cellulose oligosaccharide may be adopted. If the cellulose oligosaccharide is recovered by agglomerating it, and the acid concentration of a liquid containing dissolved cellulose oligosaccharide is adjusted to the acid concentration (55 to 63% by mass) to be adjusted for recovering hemicellulose oligosaccharideelute, the liquid containing dissolved cellulose oligosaccharide can be repeatedly used at the previous stage without adjusting the acid concentration thereof after treatment. [0039] The supernatant obtained by removing the insoluble fraction from the liquid reaction mixture containing the cellulose oligosaccharide is filtrated with a filter 15 produced from a cellulose base material to separate a filtrate containing a cellulose oligosaccharide component with a low-polymerization degree from a cellulose oligosaccharide component with a relatively high-polymerization degree, followed by decreasing the acid concentration of the filtrate containing a cellulose oligosaccharide component with a low-polymerization degree to 30 to 63% by mass to agglomerate the cellulose oligosaccharide component with a low-polymerization degree to invert into a cellulose oligosaccharide with a high-polymerization degree. The term "low-polymerization degree" means the average polymerization degree of 2 to 4, and the term "relatively high-polymerization degree" means the average polymerization degree of 5 to 15. The "average polymerization degree" is determined by determining the quantity of the reducing sugar by a Somogyi-Nelson method after determining the total sugar content by a phenolsulfuric acid method. [0040] In at least one treatment step of a series of treatment steps in which a solid biomass is successively treated using at least two acid-treatment liquids with different acid concentrations, the concentration of a saccharide composition contained in the supernatant is increased by adding solid matter containing the saccharide composition to be separated in the treatment step to the separated supernatant and then subjecting the mixture to reaction. In the following, an aspect in which the concentration of sugar components is increased in the first and second acid-treatment steps, the first acid-treatment step being a step of treating a wood biomass raw material with 55 to 63% by mass of an acid and then separating the supernatant containing a hemicellulose oligosaccharide composition from an insoluble fraction, and the second acid-treatment step being a step of treating the insoluble fraction obtained in the first acid-treatment step with 64 to 70% by mass of an acid to obtain a cellulose oligosaccharide, will be explained. In the first acid-treatment step, the concentration of hemicellulose oligosaccharide in the supernatant can be increased by adding a fresh wood biomass raw material to the separated supernatant and then subjecting the mixture to reaction. Next, 16 in the second acid-treatment step, the concentration of cellulose oligosaccharide in the supernatant can be increased by adding an insoluble fraction separated in another first acid-treatment step to the separated supernatant and then subjecting the mixture to reaction. [0041] According to the prior arts, a carbohydrate solution obtained by the acid saccharification is a mixture of oligosaccharides or monosaccharides derived from hemicellulose or cellulose, and membrane-treatment or chromatography such as ion-exchange chromatography or reversed-phase chromatography is required to be performed to isolate the components. According to the present invention, a hemicellulose oligosaccharide, a cellulose oligosaccharide, and a glucose can be separated without using any enzymes with a high substrate specificity. The cellulose oligosaccharide obtained after removing the hemicellulose oligosaccharide can be converted into the glucose by hydrolyzing with an acid or an enzyme. Alternatively, the cellulose oligosaccharide can be provided in a state of cellooligosaccharide as a functional food or the like. EXAMPLES [0042] In the following, the present invention will be explained in more detail with reference to examples. However, the present invention is not limited to the following examples. "%" used in the examples is based on the total mass, and the additive rate with respect to a wood biomass material is based on the absolute dry mass, unless otherwise so indicated. The average polymerization degree is determined by determining the quantity of reducing sugar by a Somogyi-Nelson method after determining the total sugar content by a phenol sulfuric acid method. In order to determine the quantity, "Method for quantitative determination of reducing sugar" (written by Sakuzo Fukui, Japan Scientific Societies Press) was used as a reference. [0043] 17 <Reference Example I> 100 mg of cryptomeria powders with an average particle size of 0.5 mm were put into each of three plastic test tubes and then 10 ml of 49% sulfuric acid was added thereto. The mixture was stirred with a stirrer at 25*C for 8 hours to obtain a liquid reaction mixture. The same procedures were repeated except that 53%, 57%, 61%, or 65% sulfuric acid was used. The liquid reaction mixture was centrifuged to separate into a supernatant and a precipitate. A saccharide composition with a total sugar content of 1.4 mg to 53.1 mg was obtained from the obtained supernatant. The recovery rate of the total sugar in the saccharide composition, and the average polymerization degree determined by quantitative determination of reducing terminals are shown in Table 1. Each value in the table is the arithmetic mean value of the three test tubes. [0044] Table 1. Number Concentration of Recovery rate Polymerization degree sulfuric acid % (%) _ Reference Example 49 3.0 13.02 1-1 49 3.0 Reference Example 53 8.3 12.48 1-2 53_8.3 Reference Example 57 14.2 11.31 1-3 Reference Example 61 20.8 9.62 1-4 Reference Example 65 53.1 4.38 1-5 65_53.1 [0045] <Reference Example 2> The same saccharide composition as that of Reference Example 1-4 was prepared and diluted 20 times with distilled water. The diluted composition was treated with an autoclave at 1 I0OT for 30 minutes, and hydrolyzed to obtain monosaccharides. As a result of analysis with an ion chromatograph manufactured by DIONEX Corporation, it was revealed that the resultant contained 4.4 mg of xylose, 7.1 mg of mannose, 2.7 mg of galactose, 2.1 mg of arabinose, and 4.5 mg of glucose. The result 18 of the ion chromatography is shown in FIG. 1. [0046] <Reference Example 3> The same saccharide composition as that of Reference Example 1-5 was prepared and diluted 20 times with distilled water. The diluted composition was treated with an autoclave at 1 I0*C for 30 minutes, and hydrolyzed to obtain monosaccharides. As a result of analysis with an ion chromatograph manufactured by DIONEX Corporation, it was revealed that the resultant contained 4.8 mg of xylose, 13.1 mg of mannose, 4.6 mg of galactose, 2.9 mg of arabinose, and 27.7 mg of glucose. [0047] <Reference Example 4, and Example I> 100 mg of cryptomeria powders with an average particle size of 0.5 mm were put into each of plural plastic test tubes and then 10 ml of 61% sulfuric acid was added thereto. The mixture was stirred with a stirrer at 25*C for 8 hours to obtain a liquid reaction mixture at the first stage. The liquid reaction mixture was centrifuged to separate it into a supernatant and a precipitate. The above-procedures were performed under the same conditions as those of Reference Example 1-4. Plural samples were prepared and subjected to the following examples. The supernatant was transferred to another test tube. The precipitate was left in the test tube, and 10 ml of 63% sulfuric acid was added thereto, followed by stirring for 4 hours at 25*C to obtain a liquid reaction mixture at the second stage. The liquid reaction mixture was then centrifuged to obtain a supernatant. A saccharide composition with a total sugar content of 17.4 mg was obtained from the supernatant. This example is named as Example 1-1. The same procedures were performed except that 65%, 67%, or 69% sulfuric acid was added to the precipitate at the first stage instead of the 63% sulfuric acid, to obtain each liquid reaction mixture at the second stage. The examples are named as Examples 1-2, 1-3, and 1-4, respectively. For the purpose of reference, the same procedures were performed except that 61% sulfuric acid was used to obtain a liquid 19 reaction mixture at the second stage, and the example is named as Reference Example 4. Each saccharide composition obtained as the liquid reaction mixture at the second stage was measured in terms of the recovery rate of the total sugar and the average polymerization degree determined by quantitative determination of reducing terminals in the same way as that of Reference Example 1, and results thereof are shown in Table 2. [0048] It was revealed in the example that the sum of the recovery rate of sugars in the liquid reaction mixture obtained by treatment with 61% sulfuric acid (Reference Example 1-4: the recovery rate was 20.8%) and the recovery rate of sugars in a liquid reaction mixture obtained by treating the residue with 65% sulfuric acid (Example 1-2: the recovery rate was 29.8%) was approximately equal to the recovery rate of sugars in the liquid reaction mixture obtained by the first stage treatment with 65% sulfuric acid (Reference Example 1-5: the recovery rate was 53.1%). In addition, it was revealed that the total recovery rate was not changed even if the concentration of the sulfuric acid at the second stage was increased. [0049] Table 2. Concentration of Polymerization sulfuric acid (%) Recovery rate (%) degree Reference Example 4 61 3.82 9.48 Example 1-1 63 17.4 7.26 Example 1-2 65 29.8 4.42 Example 1-3 67 29.7 4.37 Example 1-4 69 28.6 4.23 [0050] <Example 2> When the saccharide composition solution obtained as the liquid reaction mixture at the second stage in Example 1-2 was analyzed with an ion chromatograph manufactured by DIONEX Corporation in the same way as that of Reference Example 3, it was revealed that cellooligosaccharides with polymerization degrees of 10 or lower were contained (see FIG. 2). The saccharide composition solution was hydrolyzed to 20 obtain monosaccharides, and analyzed with an ion chromatograph manufactured by DIONEX Corporation. As a result, it was revealed that 95% or more of glucose was contained (see FIG. 3). It was revealed in the examples that sugars derived from hemicellulose were mainly extracted at the first stage and sugars derived from cellulose were mainly extracted at the second stage. [0051] <Example 3> The same procedures were performed as those of Example 1-2, except that the reaction temperature at the second stage for obtaining the liquid reaction mixture using 65% sulfuric acid was changed to 0*C, 20*C, 30'C, 35*C, 40*C, 50*C, or 60'C from 25*C. The reaction temperature, the content of the saccharide composition (recovery rate), and the average polymerization degree are shown in Table 3. The results of Example 1-2 in Table 2 are also shown as the results thereof in Table 3. It was revealed in the examples that the temperature does not significantly affect the recovery rate of sugars, but the temperature significantly affects the polymerization degree of recovered sugars. [0052] Table 3. Reaction temperature (*C) Recovery rate (%) Polymerization degree Example 3-1 0 21.7 8.48 3-2 20 24.9 6.5 1-2 25 29.8 4.42 3-3 30 29.6 4.28 3-4 35 29.5 4.16 3-5 40 29.7 3.87 3-6 50 27.2 3.21 3-7 60 26.1 2.87 [0053] <Example 4> Each of fine crystal cellulose powders (product name: FUNACELL) manufactured by Funakoshi Corporation., magazinewaste paper, cardboard base paper, toilet paper (manufactured by Oji paper Co., Ltd., under the product name of Nepia), and 21 soy-sauce lees was pulverized with a planetary ball mill manufactured by FRITCH INC. 100 mg of each resultant was put into each plastic test tube, and then subjected to treatment under the same conditions as those of Example 1-2 to obtain each liquid reaction mixture at the second stage. The content of saccharide compositions (recovery rate) and the average polymerization degree thereof are shown in Table 4. For comparison, the data of Example 1-2 are also shown in the table. It was revealed in the examples that various kinds of wood biomass raw materials can be used. [0054] Table 4. Biomass raw material Recovery rate % Polymerization de ree Example 1-2 Cryptomeria powders 29.8 4.42 4-1 FUNACELL 25 5.92 4-2 Magazinewaste paper 18.4 5.21 4-3 Cardboard base paper 16.3 5.34 4-4 Toilet paper 45.8 4.28 4-5 Soy-sauce lees 18.4 5.13 [0055] <Example 5> 100 mg of wood powders with an average particle size of 0.5 mm of Cryptomeria, Japanese cypress, quercus serrata, or mallee, were treated in a similar way to that of Example 1-2, except that the reaction at the second stage was performed at 27*C for 2 hours, to obtain each liquid reaction mixture at the second stage. Each saccharide composition of the liquid reaction mixtures at the first and second stages was hydrolyzed to obtain monosaccharides and the monosaccharides were analyzed with an ion chromatograph manufactured by DIONEX Corporation. The results of ion chromatography are shown in FIGs. 4 to 11. The relationships of the figures and samples are described in the section "BRIEF DESCRIPTION OF THE DRAWINGS". It was revealed in the examples that various tree species of wood biomasses can be used. [0056] <Example 6> Each liquid reaction mixture at the second stage was obtained in a similar way to 22 that of Example 1-2, except that cryptomeria powders with an average particle size of 0.25 mm, 0.1 mm, or 0.05 mm were used. The examples are named as Examples 6-1 to 6-3. The content of saccharide composition (recovery rate) and the average polymerization degree of each liquid reaction mixture at the second stage, and the size of each raw material are shown in Table 5, and the data of Example 1-2 are also shown therein for comparison. Each liquid reaction mixture was obtained at the second stage in a similar way to that of Example 1-2, except that cryptomeria shavings which passed through a mesh sieve with 1-, 5-, 10-, or 20- mm openings were used. The examples are named as Examples 6-4 to 6-7. The content of saccharide composition (recovery rate) and the average polymerization degree of each liquid reaction mixture at the second stage, and the size of each raw material are shown in Table 5. It was revealed in the examples that the particle size of the used wood biomass raw material did not affect the recovery rate, provided that the particle size was 10 mm or less. [0057] Table 5. Size of raw material Recovery rate (%) Polymerization degree Example 6-1 0.05 mm 24.5 4.26 6-2 0.1 mm 23.2 4.21 6-3 0.25 mm 30.2 4.37 Example 1-2 0.5 mm 29.8 4.42 Example 6-4 1 mm 29.2 4.49 6-5 5 mm 28.7 4.53 6-6 10 mm 26.5 4.82 6-7 20 mm 13.2 5.18 [0058] <Example 7> The liquid reaction mixture at the second stage was prepared in plural test tubes in the same way as that of Example 1-2, and then subjected to Examples 7 and 8 as shown below. In the preparation, a liquid reaction mixture at the first stage using 61% sulfuric acid was recovered in a fresh test tube as Fraction 1 (Fr. 1). The supernatant of the liquid reaction mixture at the second stage using 65% sulfuric acid was recovered in a 23 fresh test tube as Fraction 2 (Fr. 2). 1 ml of the liquid reaction mixture in the test tube of Fr. 2 was put into a 100 ml beaker, and then 19 ml of water at 20*C was added thereto to yield a large amount of precipitate. The precipitate (Fr. 4) was separated from the supernatant (Fr. 3) using a centrifuge (at 15,000 rpm for 15 minutes at 20'C), and the supernatant and the precipitate were recovered. The content of each saccharide composition (recovery rate) and the average polymerization degree thereof are shown in Table 6. It was revealed in the example that an oligosaccharide with a high polymerization degree was able to be separated by utilizing the difference of the solubility. [0059] Table 6. Fraction Recovery rate (%) Polymerization degree Fr. 1 20.8 9.62 Fr. 2 29.8 4.42 Fr. 3 23.2 4.02 Fr. 4 6.1 16.8 [0060] <Example 8> Fr. 2 was neutralized with 3N NaOH, and the neutralized liquid was mixed with Ig of fine crystal cellulose powders manufactured by Funakoshi Corporation., (product name: FUNACELL), and then the mixture was stirred at 25*C for an hour at 50 rpm. After the treatment, the supernatant (Fr. 5) was removed therefrom, and the precipitate was washed with purified water several times. Then, 2 ml of 70% ethanol was added to the precipitate, and stirred at 25'C for an hour at 50 rpm. Then, the supernatant (Fr. 6) was recovered. 100 mg of an activated carbon (manufactured by WAKO under the product number of 034-18051) was added to I ml of Fr. 5, and then stirred at 25*C for an hour at 50 rpm. Then, the supernatant was removed, and the activated carbon was washed with purified water several times. 2 ml of 70% ethanol was added to the activated carbon, and stirred at 25*C for an hour at 50 rpm, and then the supernatant (Fr. 7) was obtained to 24 remove salts of sulfuric acid, NaOH, and the like. The recovery rate and the average polymerization degree of the obtained oligosaccharides are shown in Table 7. It was revealed in the example that oligosaccharides with different polymerization degrees were able to be separated due to the difference of the adsorptivity thereof by using crystalline cellulose or activated carbon. [0061] Table 7. Fraction Recove rate Polymerization degree Fr. 5 20.3 3.54 Fr. 6 5.8 17.12 Fr. 7 13.1 3.21 [0062] <Example 9> 10 ml of Fr. 2 or 10 ml of the supernatant of Reference Example 3 was collected, and the pH thereof was adjusted to 4.5 with 5N NaOH. I ml of 1% cellulase T AMANO 4, (manufactured by Amano Enzyme Inc.) dissolved in 0.2 M acetic acid buffer (pH 4.5) was added to the resultant, and purified water was further added thereto so that the total amount of the mixutre was 20 ml. Then, the resultant was maintained at 45*C for 72 hours to perform enzymatic treatment. The treatment was performed in a similar way to the above except that an enzyme liquid inactived by boiling was used as a control. After the treatment, the supernatant was recovered, the glucose content was measured by an ion chromatograph, and the recovery rate thereof is shown in Table 8. It was revealed in the example that the obtained oligosaccharide was able to be decomposed to monosaccharides by a cellulase. [0063] Table 8. Fraction
.
Recovery rate (%) Fr. 2 29.8 Supernatant of Reference Example 3 48.2 [0064] <Example 10> 25 The precipitate obtained at the first stage in the same way as that of Example 1-1 was added to Fr. 2, and stirred at 25*C for 8 hours to obtain a liquid reaction mixture at the second stage. The liquid reaction mixture was separated into the supernatant (Fr. 8) and the precipitate by centrifugation. Another precipitate freshly obtained at the first stage in the same way as that of Example 1-1 was added to Fr. 8, and then the resultant was treated in the same way to obtain the third-time supernatant (Fr. 9) of a liquid reaction mixture. The same procedures were repeated to obtain the fourth-time supernatant (Fr. 10), fifth-time supernatant (Fr. 11), and sixth-time supernatant (Fr. 12) of each liquid reaction mixture, and the recovery rate of the total sugar content thereof and the average polymerization degree thereof are shown in Table 9. It was revealed in the example that the sugar content in the liquid reaction mixture was able to be increased. [0065] Table 9. Fraction Recovery rate (%) Polymerization degree Total sugar content (mg) Fr. 2 29.8 4.42 29.8 Fr. 8 27.2 4.38 57 Fr. 9 26.8 4.27 83.8 Fr. 10 24.9 4.3 108.7 Fr. 11 24.2 4.28 132.9 Fr. 12 23.7 4.18 156.6 [0066] <Example 11> 100 mg of cryptomeria powders with an average particle size of 0.5 mm was put into each of plural plastic test tubes, and 10 ml of 10 to 70% acid was added thereto, respectively. Each mixture was stirred at 25'C for 8 hours using a stirrer to obtain each liquid reaction mixture at the first stage. The acid used was sulfuric acid, phosphoric acid, nitric acid, hydrofluoric acid, hydrochloric acid, acetic acid, trifluoroacetic acid, or formic acid. Since high concentrations of nitric acid, hydrofluoric acid, and hydrochloric acid were not easily available, the highest concentrations thereof were 60%, 40%, and 30%, respectively. Each liquid reaction mixture was separated into the supernatant and the precipitate by centrifugation. The recovery rate of the total sugar content of each liquid reaction mixture is shown in Table 10.
26 It was revealed in the example that the highest sugar recovery rate was achieved by using sulfuric acid. [0067] Table 10. W/W% H 2
SO
4
H
3
PO
4 HN0 3 HF HCl CH 3 COOH CF 3 COOH HCOOH 70 48.7% 0.6% 1.2% 2.5% 0.8% 60 20.6% 0.5% 5.2% 1.1% 1.8% 0.6% 50 4.2% 0.3% 2.3% 0.9% 1.6% 0.5% 40 1.0% 0.2% 0.9% 5.3% 0.8% 1.2% 0.4% 30 0.9% 0.2% 0.5% 3.2% 9.4% 0.7% 1.0% 0.3% 20 0.5% 0.1% 0.3% 1.1% 2.0% 0.6% 0.8% 0.3% 10 0.3% 0.1% 0.2% 0.2% 0.8% 0.4% 0.5% 0.2% INDUSTRIAL APPLICABILITY [0068] As described above, saccharide compositions which may be useful biochemical raw materials or energy sources can be obtained according to the present invention using wood biomasses, such as, for example, building waste lumber, industrial waste, domestic waste, agricultural waste, most of which are conventionally treated by reclamation or incineration, or lumber from thinning, or waste matter containing a high content of wood biomass. Thus, contribution to resolution of environmental issues is expected. Since the oligosaccharides provided at low cost according to the present invention are expected to serve as anticaries sweeteners and effect regulation of intestinal function by selectively promoting proliferation of enterobacteria, the oligosaccharides are expanded in application as useful sugars to be formulated in lactic acid beverages or food approved as specified health foods in the same way as dietary fiber, and are expected to be further expanded in application as an emulsifier, moisturizing agent, or the like, in the field of medicine or sanitation.