WO2014065364A1 - Method for manufacturing organic acid or salt thereof - Google Patents

Abstract

In the present invention, a step (1) for obtaining a membrane-permeable liquid by passing an organic acid fermentation liquid through an ultrafiltration membrane having a molecular-weight cutoff of 3500 or less, the organic acid fermentation liquid having, as a raw material, glucose derived from cellulose-containing biomass; and a step (2) for crystallizing an organic acid or salt thereof from the membrane permeable liquid are performed to make it possible to perform high-purity crystallization of an organic acid or salt thereof from an organic acid fermentation liquid, which has been difficult using conventional methods.

Description

Method for producing organic acid or salt thereof

The present invention relates to a method for producing a high-purity organic acid or a salt thereof from an organic acid fermentation broth using sugar derived from cellulose-containing biomass as a raw material.

In recent years, the release of global warming substances such as carbon dioxide due to large consumption of oil has become a problem. From the viewpoint of breaking away from excessive dependence on fossil resources, the use of biomass resources is rapidly gaining importance, and the production of biofuels and chemical products from biomass resources is now active worldwide. In particular, the scale for producing ethanol, organic acids such as lactic acid and succinic acid, etc., from so-called edible resources such as corn, sugarcane, and cassava is increasing. In particular, organic acids can also be used as monomers for producing biomass-derived plastics such as polylactic acid (Patent Document 1) and PBS (Patent Document 2). Since fermented liquor derived from edible resources contains many impurities in addition to organic acids, technologies for purifying fermented liquor derived from edible resources to obtain high-purity lactic acid have been developed (Patent Documents 3 and 4). .

On the other hand, organic acid production from edible resources is causing social problems. In other words, because farmland suitable for production is limited globally and the population is increasing worldwide, the competition with the production of human crops and animal feed is fierce, leading to ethical problems such as rising food prices. is doing. In the future society, the problem of “competition with food” cannot be avoided. Therefore, research and development related to a technology for producing sugar from this fermented raw material from renewable non-edible resources, that is, cellulose-containing biomass, and converting the obtained sugar into an organic acid such as lactic acid by fermentation technology are being actively promoted. (Patent Document 5).

JP 2005-229822 A JP 2003-253105 A Special table 2003-511360 gazette JP 2011-172492 A WO2010 / 067785

The present inventor has studied the production of organic acids from cellulose-containing biomass based on the above-mentioned social issues based on the prior art. As a result, sugar was obtained from cellulose-containing biomass, a fermentation broth containing an organic acid was produced by fermentation technology, the organic acid was purified from the fermentation broth, and the production of the organic acid was attempted. Crystallization of the organic acid or salt thereof does not proceed in the crystallization step of the organic acid or salt thereof for improving the purity of the organic acid. Furthermore, the purity of the organic acid or salt thereof is also changed from the edible raw material sugar to the fermentation raw material. I found a problem that it was greatly reduced compared to the case.

In order to solve the above-mentioned problems, the present inventors have intensively studied. As a result, the organic acid fermentation liquid using sugar derived from cellulose-containing biomass as a raw material contains a substance having a molecular weight larger than 3500 that is considered to be derived from cellulose-containing biomass. And the crystallization of the organic acid or salt thereof is found to be inhibited by the substance, and the filtrate crystals are filtered by filtering the organic acid fermentation broth through an ultrafiltration membrane of a specific fractional molecular weight. It has been found that a high-purity organic acid or a salt thereof can be obtained, which is comparable to a fermentation liquid from a sugar derived from a conventional edible raw material.

That is, the present invention comprising the following [1] to [8] was completed.
[1] A step (1) of obtaining a membrane permeate by passing an organic acid fermentation broth using sugar derived from cellulose-containing biomass as a raw material through an ultrafiltration membrane having a molecular weight cut off of 3500 or less; The manufacturing method of an organic acid including the process (2) of crystallizing a salt.
[2] The method for producing an organic acid or a salt thereof according to [1], wherein the organic acid is lactic acid and / or succinic acid.
[3] The method for producing an organic acid or salt thereof according to [1] or [2], wherein the ultrafiltration membrane has a molecular weight cut-off of 1000 or less.
[4] The membrane permeation liquid in the step (1) is subjected to ion exchange treatment, and the obtained treatment liquid is subjected to the step (2) to obtain an organic acid crystal, [1] to [3] The manufacturing method of the organic acid or its salt in any one of.
[5] Production of organic acid or salt thereof according to any one of [1] to [3], wherein an organic salt crystal is obtained by adding an inorganic salt or an aqueous solution thereof as the step (2). Method.
[6] The process of [1] to [5], wherein the membrane permeate obtained in the step (1) is concentrated through a nanofiltration membrane or a reverse osmosis membrane, and then the step (2) is performed. The manufacturing method of the organic acid or its salt in any one.
[7] The method for producing an organic acid or salt thereof according to any one of [1] to [6], wherein the functional surface of the ultrafiltration membrane is an organic material.
[8] The method for producing an organic acid or a salt thereof according to [7], wherein the organic material contains polyethersulfone, polysulfone, sulfonated polysulfone, polyethylene glycol, polyamide, or polyvinylidene fluoride.

According to the present invention, an organic acid present in a fermentation broth derived from cellulose-containing biomass or a component that inhibits crystallization of a salt thereof is applied to an ultrafiltration membrane having a fractional molecular weight of 3500 or less, whereby a high-purity organic acid or The salt can be obtained. Furthermore, the ultrafiltration membrane treatment removes the solid polymer component of the filtrate, and has the effect of suppressing fouling when concentrating using a reverse osmosis membrane, for example, yield and efficiency of the crystallization process When concentrating the fermented liquid for improving the temperature, it is possible to significantly reduce the energy for purifying the organic acid compared to the case of evaporating water.

[Manufacturing process of sugar derived from biomass containing cellulose]
Examples of the cellulose-containing biomass include herbaceous biomass such as bagasse, switchgrass, corn stover, corn cob, rice straw, and straw, and woody biomass such as trees and waste building materials. These cellulose-containing biomass contains cellulose or hemicellulose which is a polysaccharide obtained by dehydrating and condensing saccharides, and it is possible to produce a saccharified solution that can be used as a fermentation raw material by hydrolyzing such a polysaccharide.

The sugar derived from cellulose-containing biomass refers to a sugar obtained by hydrolysis of cellulose-containing biomass. In general, sugars are classified according to the degree of polymerization of monosaccharides, such as monosaccharides such as glucose and xylose, oligosaccharides obtained by dehydration condensation of 2 to 9 monosaccharides, and polysaccharides obtained by dehydration condensation of 10 or more monosaccharides. Although classified into saccharides, the saccharide derived from cellulose-containing biomass in the present invention contains a monosaccharide as a main component, specifically, glucose and / or xylose as a main component, and, in addition, although it is a small amount, cellobiose And oligosaccharides such as arabinose and mannose. Here, the main component being a monosaccharide means that 80% by weight or more of the total weight of monosaccharide, oligosaccharide and polysaccharide saccharide dissolved in water is a monosaccharide. As a specific method for analyzing monosaccharides, oligosaccharides and polysaccharides dissolved in water, HPLC can be used for quantification by comparison with a standard product. Specific HPLC conditions were as follows: no reaction solution, Luna NH ₂ (Phenomenex) was used for the column, the mobile phase was ultrapure water: acetonitrile = 25: 75, the flow rate was 0.6 mL / min, and the measurement time. Is 45 min, the detection method is RI (differential refractive index), and the temperature is 30 ° C.

When the cellulose-containing biomass is subjected to hydrolysis, the cellulose-containing biomass may be used as it is, but it is possible to perform known treatments such as steaming, pulverization, and explosion, and the efficiency of hydrolysis can be improved by such treatment. It is possible to improve.

Although there is no restriction | limiting in particular about the hydrolysis process of cellulose containing biomass, Specifically, processing method A: The method of using only an acid, Processing method B: The method of using an enzyme after acid treatment, Processing method C: Only hydrothermal treatment , Treatment method D: hydrothermal treatment, using an enzyme, treatment method E: alkali treatment, using an enzyme, treatment method F: after ammonia treatment, using an enzyme Can be mentioned.

Treatment method A uses acid for hydrolysis of cellulose-containing biomass. Although sulfuric acid, nitric acid, hydrochloric acid, etc. are mentioned regarding the acid to be used, it is preferable to use a sulfuric acid.

The acid concentration is not particularly limited, but 0.1 to 99% by weight of acid can be used. When the acid concentration is 0.1 to 15% by weight, preferably 0.5 to 5% by weight, the reaction temperature is set in the range of 100 to 300 ° C., preferably 120 to 250 ° C., and the reaction time is 1 second. It is set in the range of ~ 60 minutes. The number of processes is not particularly limited, and one or more processes may be performed. In particular, when two or more processes are performed, the first process and the second and subsequent processes may be performed under different conditions.

When the acid concentration is 15 to 95% by weight, preferably 60 to 90% by weight, the reaction temperature is set in the range of 10 to 100 ° C., and the reaction time is set in the range of 1 second to 60 minutes. .

The number of acid treatments is not particularly limited, and the above treatment may be performed once or more. In particular, when two or more processes are performed, the first process and the second and subsequent processes may be performed under different conditions.

Since the hydrolyzate obtained by the acid treatment contains an acid such as sulfuric acid, it needs to be neutralized for use as a fermentation raw material. Neutralization may be performed on the acid aqueous solution from which the solid content has been removed from the hydrolyzate by solid-liquid separation, or may be performed while the solid content is still contained. The alkali reagent used for neutralization is not particularly limited, but is preferably a monovalent alkali reagent. If both acid and alkali components are divalent or higher salts during the step (2), the nanofiltration membrane will not pass through the salt, and in the process of concentration, the salt will precipitate in the solution, causing fouling of the membrane. May be a factor.

When monovalent alkali is used, ammonia, sodium hydroxide, potassium hydroxide and the like can be mentioned, but are not particularly limited.

When using an alkali reagent having a valence of 2 or more, it is necessary to reduce the amount of acid or alkali so that salt precipitation does not occur during the step (2), or a mechanism for removing the precipitate during the step (2). In the case of using a divalent or higher alkali, calcium hydroxide is preferable from the viewpoint of cost. When calcium hydroxide is used, a gypsum component is generated by neutralization, and therefore it is necessary to remove the gypsum by solid-liquid separation. The solid-liquid separation method includes a centrifugal separation method and a membrane separation method, but is not particularly limited. A plurality of types of separation steps may be provided and removed.

Hydrolysis using acid generally has a characteristic that hydrolysis occurs from a hemicellulose component having low crystallinity, and then a cellulose component having high crystallinity is decomposed. Therefore, it is possible to obtain a liquid containing a large amount of xylose derived from hemicellulose using an acid. In addition, in the acid treatment, the biomass solid content after the treatment is further subjected to a reaction at a higher pressure and a higher temperature than the treatment to further decompose a highly crystalline cellulose component and contain a liquid containing a large amount of cellulose-derived glucose. It is possible to obtain. By setting a two-stage process for performing hydrolysis, hydrolysis conditions suitable for hemicellulose and cellulose can be set, and the decomposition efficiency and sugar yield can be improved. In addition, by separating the sugar solution obtained under the first decomposition conditions and the sugar solution obtained under the second decomposition conditions, two types of sugar solutions with different monosaccharide component ratios contained in the hydrolyzate can be obtained. It becomes possible to manufacture. That is, the sugar solution obtained under the first decomposition condition can be separated mainly with xylose, and the sugar solution obtained under the second decomposition condition can be separated mainly with glucose. By separating the monosaccharide component contained in the sugar solution in this way, it becomes possible to perform the fermentation separately using fermentation using xylose in the sugar solution as a fermentation raw material and fermentation using glucose as the fermentation raw material. It is possible to select and use the most suitable microbial species for fermentation. However, sugars derived from both components may be obtained at once without separating the hemicellulose component and the cellulose component by performing a high-pressure and high-temperature treatment with an acid for a long time.

In the treatment method B, the cellulose-containing biomass is further hydrolyzed with an enzyme from the treatment liquid obtained by the treatment method A. The concentration of the acid used in the treatment method B is preferably 0.1 to 15% by weight, more preferably 0.5 to 5% by weight. The reaction temperature can be set in the range of 100 to 300 ° C., preferably 120 to 250 ° C. The reaction time can be set in the range of 1 second to 60 minutes. The number of processes is not particularly limited, and the process may be performed once or more. In particular, when the above process is performed twice or more, the first process and the second and subsequent processes may be performed under different conditions.

The hydrolyzate obtained by the acid treatment contains an acid such as sulfuric acid, and further needs to be neutralized in order to perform an enzymatic hydrolysis reaction or use as a fermentation raw material. Neutralization can be carried out in the same manner as the neutralization in treatment method A.

The enzyme may be any enzyme having cellulolytic activity, and general cellulase can be used. Preferably, exo cellulase or endo cellulase having crystalline cellulose degrading activity is used. A cellulase comprising is preferred. As such a cellulase, a cellulase produced by Trichoderma bacteria is preferable. Trichoderma bacteria are microorganisms classified as filamentous fungi, and are microorganisms that secrete a large amount of various cellulases to the outside of cells. The cellulase used in the present invention is preferably a cellulase derived from Trichoderma reesei. Moreover, in order to improve the production | generation efficiency of glucose as an enzyme used for a hydrolysis, you may add (beta) glucosidase which is a cellobiose decomposing enzyme, and may use it for a hydrolysis together with the above-mentioned cellulase. The β-glucosidase is not particularly limited, but is preferably derived from Aspergillus. The hydrolysis reaction using such an enzyme is preferably performed in the vicinity of pH 3 to 7, more preferably in the vicinity of pH 5. The reaction temperature is preferably 40 to 70 ° C. Moreover, it is preferable to perform solid-liquid separation at the end of hydrolysis by an enzyme to remove undecomposed solid content. Examples of the solid content removal method include a centrifugal separation method and a membrane separation method, but are not particularly limited. Moreover, you may use such solid-liquid separation combining multiple types.

When hydrolyzing cellulose-containing biomass using an enzyme after acid treatment, the hemicellulose having low crystallinity is hydrolyzed by acid treatment in the first hydrolysis, and then the enzyme is used as the second hydrolysis. It is preferable to hydrolyze cellulose with high crystallinity. By using an enzyme in the second hydrolysis, the hydrolysis process of the cellulose-containing biomass can be advanced more efficiently. Specifically, in the first hydrolysis with acid, hydrolysis of the hemicellulose component contained in the cellulose-containing biomass and partial decomposition of lignin occur, and the hydrolyzate is separated into an acid solution and a solid containing cellulose. The solid component containing cellulose is hydrolyzed by adding an enzyme. Since the separated / recovered dilute sulfuric acid solution contains xylose, which is pentose, as a main component, the acid solution can be neutralized to isolate the aqueous sugar solution. Moreover, the monosaccharide component which has glucose as a main component can be obtained from the hydrolysis reaction product of the solid content containing a cellulose. In addition, the sugar aqueous solution obtained by neutralization may be mixed with solid content, and an enzyme may be added here and it may hydrolyze.

In treatment method C, no special acid is added, and water is added so that the cellulose-containing biomass becomes 0.1 to 50% by weight, followed by treatment at a temperature of 100 to 400 ° C. for 1 second to 60 minutes. By treating at such temperature conditions, hydrolysis of cellulose and hemicellulose occurs. The number of processes is not particularly limited, and the process may be performed once or more. In particular, when the process is performed twice or more, the first process and the second and subsequent processes may be performed under different conditions.

Hydrolysis using hydrothermal treatment is generally characterized in that hydrolysis occurs from a hemicellulose component having low crystallinity and then a cellulose component having high crystallinity is decomposed. Therefore, it is possible to obtain a liquid containing a large amount of xylose derived from hemicellulose using hydrothermal treatment. Moreover, in the hydrothermal treatment, the biomass solid content after the treatment is further reacted at a higher pressure and a higher temperature than the treatment to further decompose the highly crystalline cellulose component to obtain a liquid containing a large amount of cellulose-derived glucose. It is possible. By setting a two-stage process for performing hydrolysis, hydrolysis conditions suitable for hemicellulose and cellulose can be set, and the decomposition efficiency and sugar yield can be improved. In addition, by separating the sugar solution obtained under the first decomposition conditions and the sugar solution obtained under the second decomposition conditions, two types of sugar solutions with different monosaccharide component ratios contained in the hydrolyzate can be obtained. It becomes possible to manufacture. That is, the sugar solution obtained under the first decomposition condition can be separated mainly with xylose, and the sugar solution obtained under the second decomposition condition can be separated mainly with glucose. By separating the monosaccharide component contained in the sugar solution in this way, it becomes possible to perform the fermentation separately using fermentation using xylose in the sugar solution as a fermentation raw material and fermentation using glucose as the fermentation raw material. It is possible to select and use the most suitable microbial species for fermentation.

In the treatment method D, the cellulose-containing biomass is further hydrolyzed with an enzyme from the treatment liquid obtained by the treatment method C.

As the enzyme, the same enzyme as in the treatment method B is used. Moreover, the same conditions as the processing method B can be employ | adopted also about enzyme processing conditions.

When hydrolyzing cellulose-containing biomass using an enzyme after hydrothermal treatment, hydrolyze hemicellulose with low crystallinity by hydrothermal treatment in the first hydrolysis, and then use the enzyme as the second hydrolysis To hydrolyze highly crystalline cellulose. By using an enzyme in the second hydrolysis, the hydrolysis process of the cellulose-containing biomass can be advanced more efficiently. Specifically, in the first hydrolysis by hydrothermal treatment, hydrolysis of the hemicellulose component contained in the cellulose-containing biomass and partial decomposition of lignin occur, and the hydrolyzate is separated into an aqueous solution and a solid containing cellulose. The solid content containing cellulose is hydrolyzed by adding an enzyme. The separated and recovered aqueous solution contains pentose xylose as a main component. Moreover, the monosaccharide component which has glucose as a main component can be obtained from the hydrolysis reaction product of the solid content containing a cellulose. In addition, the aqueous solution obtained by hydrothermal treatment may be mixed with solid content, and an enzyme may be added here and hydrolyzed.

In the treatment method E, the alkali used is more preferably sodium hydroxide or calcium hydroxide. The concentration of these alkalis may be added to the cellulose-containing biomass in the range of 0.1 to 60% by weight and treated at a temperature range of 100 to 200 ° C, preferably 110 to 180 ° C. The number of processes is not particularly limited, and one or more processes may be performed. In particular, when two or more processes are performed, the first process and the second and subsequent processes may be performed under different conditions.

Since the treated product obtained by the alkali treatment contains an alkali such as sodium hydroxide, it is necessary to carry out neutralization in order to perform an enzymatic hydrolysis reaction. Neutralization may be performed on an alkaline aqueous solution from which the solid content has been removed from the hydrolyzate by solid-liquid separation, or may be performed while the solid content is still contained. Although the acid reagent used for neutralization is not particularly limited, it is more preferably a monovalent acid reagent. If both acid and alkali components are divalent or higher salts during the step (2), the nanofiltration membrane will not pass through the salt, and in the process of concentration, the salt will precipitate in the solution, causing fouling of the membrane. It is a factor.

In the case of using a monovalent acid, nitric acid, hydrochloric acid and the like can be mentioned but are not particularly limited.

When a divalent or higher acid reagent is used, a mechanism for reducing the amount of acid and alkali so that salt precipitation does not occur during step (2), or removing the precipitate during step (2) is required. . When a divalent or higher acid is used, sulfuric acid and phosphoric acid are preferred. When calcium hydroxide is used, a gypsum component is generated by neutralization, and therefore it is necessary to remove the gypsum by solid-liquid separation. The solid-liquid separation method includes a centrifugal separation method and a membrane separation method, but is not particularly limited. A plurality of types of separation steps may be provided and removed.

As the enzyme, the same enzyme as in the treatment method B is used. Moreover, the same conditions as the processing method B can be employ | adopted also about enzyme processing conditions.

When hydrolyzing cellulose-containing biomass using an enzyme after alkali treatment, hemicellulose and the lignin component around the cellulose component are removed by mixing with an alkali-containing aqueous solution and heated to react the hemicellulose component and the cellulose component. After making it easy to perform, hydrolysis of hemicellulose having low crystallinity and cellulose having high crystallinity, which are not decomposed by hydrothermal heat during alkali treatment by an enzyme, is performed. Specifically, in the treatment with alkali, hydrolysis of some hemicellulose components mainly contained in cellulose-containing biomass and partial decomposition of lignin occur, and the hydrolyzate is separated into an alkali solution and a solid containing cellulose. The solid component containing cellulose is hydrolyzed by adjusting the pH and adding an enzyme. Further, when the alkaline solution concentration is dilute, it may be hydrolyzed by adding an enzyme after neutralization as it is without separating the solid content. A monosaccharide component mainly composed of glucose and xylose can be obtained from a hydrolysis reaction product of solids containing cellulose. Further, since the separated / recovered alkaline solution contains xylose, which is pentose, as a main component in addition to lignin, it is also possible to neutralize the alkaline solution and isolate the aqueous sugar solution. Moreover, the sugar aqueous solution obtained by neutralization may be mixed with solid content, and it may hydrolyze by adding an enzyme here.

The ammonia treatment conditions for Treatment Method F are in accordance with JP2008-161125A and JP2008-535664A. For example, the ammonia concentration to be used is added to the cellulose-containing biomass in the range of 0.1 to 15% by weight with respect to the cellulose-containing biomass, and is treated at 4 to 200 ° C., preferably 90 to 150 ° C. Ammonia to be added may be in a liquid state or a gaseous state. Further, the form of addition may be pure ammonia or an aqueous ammonia solution. The number of processes is not particularly limited, and the process may be performed once or more. In particular, when the process is performed twice or more, the first process and the second and subsequent processes may be performed under different conditions.

Since the treated product obtained by the ammonia treatment is further subjected to an enzymatic hydrolysis reaction, it is necessary to neutralize ammonia or remove ammonia. Neutralization may be performed on ammonia from which the solid content has been removed from the hydrolyzate by solid-liquid separation, or may be performed while the solid content is still contained. The acid reagent used for neutralization is not particularly limited. For example, hydrochloric acid, nitric acid, sulfuric acid and the like can be mentioned, and sulfuric acid is more preferable in consideration of the corrosiveness of the process piping and not becoming a fermentation inhibiting factor. Ammonia can be removed by volatilizing ammonia into a gaseous state by keeping the ammonia-treated product in a reduced pressure state. The removed ammonia may be recovered and reused.

In the hydrolysis using an enzyme after ammonia treatment, it is known that the crystal structure of cellulose is generally changed by the ammonia treatment to change to a crystal structure that is susceptible to an enzyme reaction. Therefore, it can hydrolyze efficiently by making an enzyme act on the solid content after such ammonia treatment. As the enzyme, an enzyme similar to the treatment method B is used. Moreover, the same conditions as the processing method B can be employ | adopted also about enzyme processing conditions.

In addition, when an aqueous ammonia solution is used, the water component may have the same effect as the treatment method C (hydrothermal treatment) in addition to ammonia during the ammonia treatment, and the hydrolysis of hemicellulose and the decomposition of lignin may occur. When hydrolyzing cellulose-containing biomass using an enzyme after treatment with an aqueous ammonia solution, the lignin component around the hemicellulose and the cellulose component is removed by mixing and heating to an aqueous solution containing ammonia, and the hemicellulose component and the cellulose component After making it easy to react, hydrolysis of hemicellulose having low crystallinity and cellulose having high crystallinity that are not decomposed by hydrothermal heat during ammonia treatment by an enzyme is performed. Specifically, in the treatment with an aqueous ammonia solution, hydrolysis of some hemicellulose components and partial decomposition of lignin occur mainly in the cellulose-containing biomass, and the hydrolyzate is separated into an aqueous ammonia solution and a solid containing cellulose. The solid component containing cellulose is hydrolyzed by adjusting the pH and adding an enzyme. Further, when the ammonia concentration is close to 100%, after removing a large amount of ammonia by deaeration, it may be hydrolyzed by adding enzyme after neutralization as it is without separating the solid content. A monosaccharide component mainly composed of glucose and xylose can be obtained from a hydrolysis reaction product of solids containing cellulose. Further, since the separated and recovered aqueous ammonia solution contains xylose which is pentose in addition to lignin as a main component, it is possible to neutralize the alkaline solution and isolate the aqueous saccharide solution. Moreover, the sugar aqueous solution obtained by neutralization may be mixed with solid content, and it may hydrolyze by adding an enzyme here.

Since the sugar derived from the cellulose-containing biomass obtained as described above contains a fermentation inhibiting substance, the fermentation inhibiting substance may be appropriately removed or reduced before being subjected to the subsequent step of producing the organic acid fermentation broth. As a method for removing the fermentation inhibitor from sugar derived from cellulose-containing biomass, for example, the method described in WO2010 / 067785 can be mentioned.

[Process for producing an organic acid fermentation broth using sugar derived from cellulose-containing biomass as a raw material]
In this step, an organic acid fermentation broth is produced by microbial fermentation using sugar derived from cellulose-containing biomass as a raw material. In addition, the organic acid contained in the organic acid fermentation liquid obtained in this step may be in a free form of organic acid or in an organic acid salt state.

The microorganism for producing the organic acid fermentation broth is not particularly limited. For example, yeasts such as baker's yeast often used in the fermentation industry, bacteria such as Escherichia coli and coryneform bacteria, filamentous fungi, actinomycetes, animal cells, insect cells and the like can be mentioned. The microorganisms and cells used may be those isolated from the natural environment, or may be those whose properties have been partially modified by mutation or genetic recombination. In particular, since the sugar solution derived from cellulose-containing biomass contains pentose such as xylose, microorganisms with enhanced pentose metabolic pathway can be preferably used.

As a method for producing an organic acid fermentation broth by microbial conversion from sugar derived from cellulose-containing biomass, a fermentation culture method known to those skilled in the art can be employed.

As a medium for fermentation culture, in addition to sugar derived from cellulose-containing biomass, a liquid medium suitably containing a nitrogen source, inorganic salts, and if necessary, organic micronutrients such as amino acids and vitamins is preferably used. The purified sugar liquid of the present invention contains monosaccharides that can be used by microorganisms, such as glucose and xylose, as a carbon source. In some cases, glucose, sucrose, fructose, galactose, lactose, etc. Saccharides, starch saccharified solution containing these saccharides, sweet potato molasses, sugar beet molasses, high test molasses, organic acids such as acetic acid, alcohols such as ethanol, glycerin and the like may be added and used as a fermentation raw material. Nitrogen sources include ammonia gas, aqueous ammonia, ammonium salts, urea, nitrates, and other supplementary organic nitrogen sources such as oil cakes, soybean hydrolysates, casein degradation products, other amino acids, vitamins, Corn steep liquor, yeast or yeast extract, meat extract, peptides such as peptone, various fermented cells and hydrolysates thereof are used. As inorganic salts, phosphates, magnesium salts, calcium salts, iron salts, manganese salts, and the like can be appropriately added.

When microorganisms require specific nutrients for growth, the nutrients may be added as preparations or natural products containing them. Moreover, you may use an antifoamer as needed.

The pH and temperature at the time of microbial conversion are not particularly limited, and for example, the pH is 4 to 8 and the temperature is 20 to 40 ° C. The pH of the culture solution is usually adjusted to a predetermined value within a pH range of 4 to 8 with an inorganic or organic acid, an alkaline substance, urea, calcium carbonate, ammonia gas, or the like. If it is necessary to increase the oxygen supply rate, means such as adding oxygen to the air to keep the oxygen concentration at 21% or higher, pressurizing the culture, increasing the stirring rate, or increasing the aeration rate can be used.

The organic acid contained in the organic acid fermentation liquid obtained in this step is not limited as long as it is an organic acid produced by the microorganism or cell in the culture solution. Specific examples include lactic acid, succinic acid, acetic acid. , Pyruvic acid, malic acid, itaconic acid, citric acid, oxalic acid, tartaric acid, glycolic acid, malonic acid, 2-ketoglutaric acid, oxaloacetic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, pimelic acid, suberic acid, Azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, L-ascorbic acid, benzoic acid, paraoxybenzoic acid, anthranilic acid, erythorbic acid, sorbic acid, cinnamic acid, dehydroacetic acid, nicotinic acid, folic acid, amino acid, Examples include substances that are mass-produced in the fermentation industry, such as nucleic acids. More preferred are lactic acid, succinic acid, maleic acid, adipic acid, suberic acid, sebacic acid and terephthalic acid, and more preferred are lactic acid, succinic acid, maleic acid and adipic acid from the viewpoint of ease of crystallization. Most preferred is lactic acid or succinic acid. Moreover, 1 type may be sufficient as an organic acid, and 2 or more types of mixtures may be sufficient as it.

[Step (1): Step of obtaining a membrane permeate by passing the organic acid fermentation broth through an ultrafiltration membrane having a molecular weight cut off of 3500 or less]
The ultrafiltration membrane is a membrane having a molecular weight cut-off of 500 to 200,000, and is abbreviated as ultrafiltration, UF membrane or the like. In addition, the ultrafiltration membrane has a pore size that is too small to measure the pore size on the membrane surface with an electron microscope or the like. Instead of the average pore size, the value of the fractional molecular weight is used as an index of the pore size. Is supposed to do. The molecular weight cut-off is the Membrane Society of Japan, Membrane Experiment Series Volume III, Artificial Membrane Editor / Naofumi Kimura, Shinichi Nakao, Haruhiko Ohya, Tsutomu Nakagawa (1993, Kyoritsu Shuppan) A plot of data with the rejection rate on the axis and the data plotted on the axis is called a fractionated molecular weight curve. The molecular weight at which the blocking rate is 90% is called the fractional molecular weight of the membrane. ”Is well known to those skilled in the art as an index representing the membrane performance of the ultrafiltration membrane.

The molecular weight cutoff of an ultrafiltration membrane having an effect in the present invention is 3500 or less. As a result of purifying an organic acid fermentation broth using sugar derived from cellulose-containing biomass as a raw material, the present inventors have a substance that inhibits crystallization during crystallization (hereinafter referred to as a crystallization inhibitor). Although the crystallization inhibitor is not clear, it can be removed on the non-permeation side of the membrane with an ultrafiltration membrane having a fractional molecular weight of 3500 or less, and further, by using an ultrafiltration membrane having a fractional molecular weight of 1000 or less, This is because it has been found that not only the crystallization-inhibiting substance can be removed, but also the crystallization speed of the organic acid or its salt during crystallization is dramatically improved. In addition, although there is no restriction | limiting in particular about the minimum of the molecular weight cut off of an ultrafiltration membrane, A thing with a cut off molecular weight of 500 or more is used preferably.

The material of the functional surface of the ultrafiltration membrane is not particularly limited as long as it can achieve the object of the present invention of removing the crystal inhibiting substance, but is not limited to cellulose, cellulose ester, polysulfone, polyethersulfone, chlorine. Organic materials such as fluorinated polyethylene, polypropylene, polyolefin, polyvinyl alcohol, polymethyl methacrylate, polyvinylidene fluoride, polytetrafluoroethylene, polyamide, etc., metals such as stainless steel, or inorganic materials such as ceramics are used. The organic material is preferably an organic material from the viewpoint of the economical efficiency of the membrane, and the organic material is preferably polyethersulfone or polysulfone. Sulfonated polysulfone, poly Ji glycol, including polyamide or polyfluorinated vinylidene.

The module form of the ultrafiltration membrane is not particularly limited, and examples thereof include a hollow fiber type, a tubular type, a flat membrane type, and a spiral type. The ultrafiltration membrane used in the present invention has a molecular weight cut-off of 3500 or less. Spiral modules are preferably used, for example, SPE1 and SPE3 from Synder, NTR-7410 and NTR-7450 from Nitto Denko Corporation, GE series, GH series, GK series, and Alfa Laval / DSS from DESAL There are GR95PP, ETNA01PP, MPT-36, MPS-36 and SR2 manufactured by KOCH.

When performing filtration through an ultrafiltration membrane, it is preferable that there is a solid-liquid separation step in the previous stage. Organic acid fermentation broth contains residues of cellulose-containing biomass and solids such as microorganisms. When filtering directly with an ultrafiltration membrane, the membrane module part or the membrane itself may become clogged. Because it ends up. There are no particular limitations on the method of solid-liquid separation, but screw decanters, separation plate centrifuges, centrifugal treatments such as cyclones, sedimentation separation, compression separation such as screw presses, filter presses, belt presses, belt filters, precoat filters These may be combined with each other, and may be combined, but a method using filtration separation is more preferable. The reason why the filtration and separation is more preferable is that the clarification of the separated liquid obtained when being applied to the ultrafiltration membrane is extremely high. The membrane for filtration separation is preferably a woven fabric, a nonwoven fabric or a microfiltration membrane, and when using a woven fabric or a non-woven fabric, the effect of capturing impurities is weaker than that of the microfiltration membrane. A filter medium may be used, and the filter medium may be a substance contained in the fermentation broth.

The microfiltration membrane is a membrane having an average pore size of 0.01 μm to 5 mm, and is abbreviated as microfiltration, MF membrane, or the like. The material of the microfiltration membrane used in the present invention is not particularly limited as long as it can achieve the object of the present invention, ie, removal of a crystal inhibiting substance, but is not limited to cellulose, cellulose ester, polysulfone, polyethersulfone. Organic materials such as chlorinated polyethylene, polypropylene, polyolefin, polyvinyl alcohol, polymethyl methacrylate, polyvinylidene fluoride, and polytetrafluoroethylene, metals such as stainless steel, and inorganic materials such as ceramic.

The membrane permeate containing the organic acid or salt thereof obtained through the ultrafiltration membrane is preferably concentrated to the vicinity of the solubility of the organic acid to be crystallized before crystallization in the subsequent step (2). . Concentration methods include heating using an evaporator and vacuum concentration, concentrating the crystallization can under reduced pressure and evaporating water, and concentrating with a nanofiltration membrane and / or reverse osmosis membrane. Although not particularly limited, a method using a nanofiltration membrane and / or a reverse osmosis membrane is preferable. The use of nanofiltration membranes and / or reverse osmosis membranes can significantly reduce the energy used compared to the concentration method of evaporating water by heating and decompression, and there is a concern that membrane fouling may occur. This is because molecular components can be removed.

The nanofiltration membrane is a membrane generally defined as “a membrane that transmits monovalent ions and blocks divalent ions”, and further has a molecular weight equivalent to 100 or more and less than 500.

The module form of the nanofiltration membrane is not particularly limited. Generally, since the pore diameter is small, it is used as a spiral membrane module, but the nanofiltration membrane used in the present invention is also preferably used as a spiral membrane module. Specific examples of preferred nanofiltration membranes include, for example, GE Osmonics nanofiltration membranes DK series, HL series, DL series, HWS NF series, Alfa Laval nanofiltration membranes NF97, NF99, NF99HF, and Filmtech. NF-45, NF-90, NF-200, NF-270 or NF-400 manufactured by Nanofiltration Membrane, NTR-769SR, NTR-729HF, NTR-7250, NTR-725HF manufactured by Nitto Denko Corporation, Toray Industries, Inc. Examples thereof include UTC-60 and UTC-20 manufactured by MPO, MPS-34 manufactured by KOCH, SR3, and SR4. Examples of the tubular type include MPT-34 and MPT-31 manufactured by KOCH.

The reverse osmosis membrane is a membrane that is generally defined as a “membrane having a desalting function including monovalent ions”, and the reverse osmosis membrane used in the present invention is also called an RO membrane. It is a membrane that is thought to have ultrafine pores of several angstroms to several nanometers, and is mainly used for removing ionic components such as seawater desalination and ultrapure water production.

As a material for the reverse osmosis membrane, a composite membrane using a cellulose acetate-based polymer as a functional layer (hereinafter also referred to as a cellulose acetate-based reverse osmosis membrane) or a composite membrane using a polyamide as a functional layer (hereinafter referred to as a polyamide-based reverse osmosis) Also referred to as a membrane). Here, as the cellulose acetate-based polymer, organic acid esters of cellulose such as cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate and the like, or a mixture thereof and those using mixed esters can be mentioned. It is done. The polyamide includes a linear polymer or a crosslinked polymer having an aliphatic and / or aromatic diamine as a monomer.

Specific examples of the reverse osmosis membrane include, for example, ultra-low pressure type SUL-G10, SUL-G20, low pressure type SU-710, SU-720, SU-720F, which are polyamide-based reverse osmosis membrane modules manufactured by Toray Industries, Inc. In addition to SU-710L, SU-720L, SU-720LF, SU-720R, SU-710P, SU-720P, high pressure types including UTC80 as a reverse osmosis membrane, SU-810, SU-820, SU-820L, SU- 820FA, Cellulose acetate reverse osmosis membrane SC-L100R, SC-L200R, SC-1100, SC-1200, SC-2100, SC-2200, SC-3100, SC-3200, SC-8100, SC-8200, Nitto NTR-759HR, NTR-729HF, NTR-70SWC, E manufactured by Denko Co., Ltd. 10-D, ES20-D, ES20-U, ES15-D, ES15-U, LF10-D, Alfa Laval RO98pHt, RO99, HR98PP, CE4040C-30D, GE Osmonics GE Sepa, Filmtec BW30-4040, TW30 -4040, XLE-4040, LP-4040, LE-4040, SW30-4040, SW30HRLE-4040, KOCH TFC-HR, TFC-ULP, TRISEP ACM-1, ACM-2, ACM-4, etc. .

[Step (2): Step of recovering organic acid or salt thereof by crystallizing membrane permeate]
Crystallization of an organic acid or a salt thereof is performed by, for example, cooling the solvent to lower the solubility and / or adding an additive such as an organic solvent or a cation-derived substance to precipitate the organic acid or a salt thereof as a high-purity crystal. Say to collect.

When obtaining an organic acid salt crystal in this step, preferably, ammonium salt, lithium salt, sodium salt, potassium salt, calcium salt, magnesium salt, strontium salt, chromium salt, iron salt, manganese salt, copper salt, silver salt , Organic salts derived from cations such as cadmium salts and aluminum salts, more preferably calcium salts, magnesium salts, strontium salts, chromium salts, iron salts, manganese salts, copper salts, silver salts, cadmium salts, aluminum salts, etc. It is a divalent or higher cation-derived organic acid salt. The crystallized organic acid or salt thereof is separated and recovered as a solid by centrifugation or filtration.

When organic acid crystals are obtained in this step, it is preferable to remove the solvent once by means of a reverse osmosis membrane or distillation, and then reduce the solubility by cooling to precipitate the organic acid crystals. More preferably, the treatment step is performed before the crystallization step. The combination of the membrane treatment and the ion exchange treatment step in step (1) promotes crystallization of the organic acid, improves the yield as crystals, and greatly reduces the contamination of inorganic salts in the crystals. is there. In addition, when performing an ion exchange process, you may perform a cation exchange process, an anion exchange process, or both, but it is preferable to perform both a cation exchange process and an anion exchange process. This is because, in addition to inorganic ions derived from cellulose-containing biomass, anions derived from acids used for pH adjustment and the like are also included. It is because it inhibits. The procedure of the ion exchange treatment step is not particularly limited, and it may be a pre-step or a post-step of step (1) which is the ultrafiltration membrane step of the present invention. More preferably, it is a post process of a process (1). This is because the effect of the ion exchange resin can be prolonged.

In order to increase the crystallization speed, a method of adding a seed crystal or a method of lowering the temperature is preferably employed. The crystallization temperature is not particularly limited, but is preferably 30 ° C. or lower, more preferably 20 ° C. or lower. The recovery rate may be improved, for example, by lowering the temperature from the mother liquor recovered by removing the organic acid or its salt obtained by crystallization. The method for recovering crystals may be divided into several stages, and the temperature reduction, seed crystal addition, and the like may be performed in the middle.

As for the mother liquor after crystallization, the organic acid or its salt that could not be recovered by the crystallization operation can be concentrated and recovered by passing through the nanofiltration membrane or reverse osmosis membrane. It is preferable to concentrate through a membrane or a reverse osmosis membrane and to use for crystallization again.

Hereinafter, the method for producing an organic acid of the present invention will be described with reference to examples in order to explain in more detail. However, the present invention is not limited to these examples.

(Reference Example 1) Method for Analyzing Organic Acid Organic acids (lactic acid, succinic acid, formic acid, acetic acid, etc.) contained in the liquid were quantified by comparison with a standard under the following HPLC conditions.
Column: Shim-Pack SPR-H and Shim-Pack SCR101H (manufactured by Shimadzu Corporation) Mobile phase: 5 mM p-toluenesulfonic acid (flow rate 0.8 mL / min)
Reaction solution: 5 mM p-toluenesulfonic acid, 20 mM Bistris, 0.1 mM EDTA · 2Na (flow rate 0.8 mL / min)
Detection method: electric conductivity temperature: 45 ° C.

(Reference Example 2) Analytical Method of Furan / Aromatic Compound Furan compound (HMF, furfural) and phenol compound (coumaric acid) contained in the liquid are the HPLC conditions shown below, and compared with the standard. Quantified.
Column: Synergi HideRP 4.6 mm × 250 mm (Phenomenex)
Mobile phase: Acetonitrile-0.1% H ₃ PO ₄ (flow rate 1.0 mL / min)
Detection method: UV (283 nm)
Temperature: 40 ° C.

(Reference Example 3) Sugar Analysis Method The sugar concentration contained in the aqueous sugar solution was quantified by comparison with a sample under the HPLC conditions shown below.
Column: Luna NH ₂ (Phenomenex)
Mobile phase: Ultrapure water: Acetonitrile = 25: 75 (flow rate 0.6 mL / min)
Reaction solution: None Detection method: RI (differential refractive index)
Temperature: 30 ° C.

(Reference Example 4) Method of analyzing moisture content Regarding the moisture content of cellulose-containing biomass and its pretreated product, the sample was brought to a temperature of 120 ° C using an infrared moisture meter (FD-720, manufactured by Kett Science Laboratory). The value obtained from the difference between the stable value after evaporation and the initial value was measured.

(Reference Example 5) Hydrolysis step of cellulose-containing biomass by dilute sulfuric acid treatment / enzyme treatment Rice straw was used as the cellulose-containing biomass. The cellulose-containing biomass was immersed in a 1% aqueous solution of sulfuric acid and autoclaved (manufactured by Nitto Koatsu Co., Ltd.) at 150 ° C. for 30 minutes. After the treatment, solid-liquid separation was performed to separate into a sulfuric acid aqueous solution (hereinafter, dilute sulfuric acid treatment liquid) and sulfuric acid-treated cellulose. Next, after the sulfuric acid-treated cellulose and the dilute sulfuric acid treatment liquid were stirred and mixed so that the solid content concentration became 10% by weight in terms of absolute dry treatment biomass, the pH was adjusted to around 5 with sodium hydroxide. Accel lace duet (manufactured by Danisco Japan) was added as a cellulase to this mixed solution, and a hydrolysis reaction was carried out while stirring and mixing at 50 ° C. for 1 day to obtain a dilute sulfuric acid treatment enzyme saccharified solution. The compositions of sugar, organic acid, aromatic compound and furan compound contained in the diluted sulfuric acid-treated enzyme saccharified solution are as shown in Tables 1 and 2, respectively.

(Reference Example 6) Hydrolysis step by steam explosion treatment / enzyme treatment of cellulose-containing biomass Rice straw was used as the cellulose-containing biomass. First, 100 kg of the cellulose-containing biomass was pulverized by rotating the rice straw with a rotary cutter mill RCM-400 (manufactured by Nara Machinery Co., Ltd.) at a screen mesh diameter of 8 mm at 420 rpm. Next, 2 kg of the pulverized rice straw was subjected to steam explosion using a blasting apparatus (reaction vessel 30L, manufactured by Nippon Electric Heat Co., Ltd.). The pressure at that time was 2.5 MPa, and the treatment time was 3 minutes. After measuring the moisture content of the treated biomass component, add RO water so that the solid content concentration becomes 10% by weight in terms of the above-mentioned absolutely dry treated biomass, add Accel Race Duet (manufactured by Danisco Japan), 50 ° C Then, the mixture was stirred and mixed for 1 day to conduct a hydrolysis reaction to obtain a crushed saccharified solution. Tables 3 and 4 show the composition of sugar, organic acid, aromatic compound, and furan compound contained in the smashed saccharified solution.

(Reference example 7) Hydrolysis process by ammonia treatment and enzyme treatment of cellulose-containing biomass Rice straw was used as the cellulose-containing biomass. First, 1 kg of the cellulose-containing biomass was pulverized by rotating the rice straw with a rotary cutter mill RCM-400 type (manufactured by Nara Machinery Co., Ltd.) at a screen mesh diameter of 8 mm at 420 rpm. Next, 1 kg of the crushed rice straw was introduced into the autoclave using an autoclave device (reaction vessel 3L, manufactured by Nitto High Pressure Co., Ltd.), and ammonia treatment was performed while stirring at 120 ° C. for 10 minutes. did. After measuring the moisture content of the treated biomass component, add RO water so that the solid content concentration becomes 10% by weight in terms of the above-mentioned absolutely dry treated biomass, add Accel Race Duet (manufactured by Danisco Japan), 50 ° C The saccharified liquid was subjected to a hydrolysis reaction while stirring and mixing for 1 day. Tables 3 and 4 show the composition of sugar, organic acid, aromatic compound, and furan compound contained in the smashed saccharified solution.

(Reference Example 8) L-lactic acid fermentation method (yeast)
As the yeast producing L-lactic acid, the SW-1 strain described in Reference Example 7 described in WO2010 / 067675 was used. The medium is glucose as carbon source, Yeast Synthetic Drop-out Medium Supplement Without Triptophan (Sigma Aldrich Japan, Dropout MX), Yeast Nitrogen Base w / o Amino Acid Ammonium sulfate (ammonium sulfate) was mixed at the ratio shown in Table 7. The medium was sterilized by filter (Millipore, Stericup 0.22 μm) and used for fermentation. For determination of the glucose concentration, Glucose Test Wako (manufactured by Wako Pure Chemical Industries, Ltd.) was used. Moreover, the amount of lactic acid produced in each culture solution was measured by HPLC under the same conditions as in Reference Example 1.

Strain SW-1 was cultured overnight in a test tube with 5 mL of fermentation medium (preculture medium) (preculture). Yeast was recovered from the preculture by centrifugation and washed thoroughly with 15 mL of sterile water. The washed yeast was inoculated into 100 mL of each medium having the composition described in Table 5, and cultured with shaking in a 500 mL Sakaguchi flask for 40 hours (main culture).

(Reference Example 9) L-lactic acid fermentation method (lactic acid bacteria)
As a lactic acid bacterium, a prokaryotic microorganism Lactococcus lactis JCM7638 strain was used, and a medium for L-lactic acid fermenting lactic acid bacteria having the composition shown in Table 8 was used. L-lactic acid contained in the fermentation broth was evaluated by the same method as in Reference Example 1. In addition, glucose test Wako C (manufactured by Wako Pure Chemical Industries, Ltd.) was used for measuring the glucose concentration.

Lactococcus lactis JCM7638 strain was statically cultured at 37 ° C. for 24 hours in a lactic acid fermentation medium purged with 5 mL of nitrogen gas shown in Table 8 in a test tube (preculture). The obtained culture solution was inoculated into 50 mL of a fresh lactic acid fermentation medium purged with nitrogen gas, and statically cultured at a temperature of 37 ° C. for 48 hours (main culture).

(Reference Example 10) Crystallization of calcium lactate aqueous solution The calcium lactate solution was stirred at 50 ° C. and 400 rpm for 1, 3 and 6 hours, solid-liquid separated by suction filtration with qualitative filter paper No. 2 (manufactured by Advantech), and not dissolved. Calcium lactate was removed and the mother liquor was recovered. The calcium lactate concentration in the collected mother liquor was measured by high performance liquid chromatography in the same manner as in Reference Example 1. The collected mother liquor was used as a test solution, cooled to 20 ° C., and stirred at 400 rpm for 2 hours. The precipitated slurry was subjected to solid-liquid separation into wet crystals and mother liquor by suction filtration using qualitative filter paper No. 2 (manufactured by Advantech). The amount of calcium lactate in the wet crystal was measured by high performance liquid chromatography in the same manner as in Reference Example 1, and the calcium lactate recovery rate was calculated by the method of Formula 1.

Calcium lactate recovery rate (%) = 100 × calcium lactate amount in wet crystal (g) / calcium lactate amount in test solution (g) (Formula 1).

The reagent calcium lactate hydrate (manufactured by Kanto Chemical Co., Inc.) was dissolved in water at a concentration of 150 g / L and the above test was conducted. As a result, the recovery rate was 58%. It took 20 minutes.

Reference Example 11 Ultrafiltration Membrane Treatment and Lactic Acid Permeability Evaluation As a method of performing the membrane treatment in the step (1), GE Osmonics SEPAII was used, and the flat membrane was set to SEPAII for filtration treatment. . The flux was calculated on the assumption that the flow rate of the raw water was 2.5 L / min and the membrane area was 140 cm 2, and it was filtered under the condition of 0.5 m / day. As a method for measuring lactic acid permeability, the lactic acid concentration before ultrafiltration membrane treatment and the lactic acid concentration of the filtrate after membrane treatment are measured under the condition that the flux is 0.5 m / day in step (3). did. That is, the lactic acid permeability is expressed by the following formula 2.

Lactic acid permeability (%) = 100 × lactic acid concentration in the filtrate (g / L) / lactic acid concentration in the solution before membrane treatment (g / L) (Formula 2).

(Reference Example 12)
Fermentation was performed using edible sugar (crude sugar “Yu-Gakusei” manufactured by Muso Co., Ltd.) under the conditions of Reference Example 8, and the resulting lactic acid fermentation broth was centrifuged at 1500 G for 5 minutes, and the pore size was adjusted to 0. Lactic acid yeast was removed by filtration using a 22 μm microfiltration membrane (Millipore). Next, the fermentation filtrate is divided into ultrafiltration membranes with no membrane treatment or different molecular weight cut-off (GE Osmonics PW (fraction molecular weight 10,000, functional surface material: polyethersulfone), GK (fractionated molecular weight 3500). , Functional surface material: composite polymer mainly composed of polyamide), GE (fraction molecular weight 1000, functional surface material: composite polymer mainly composed of polyamide))), or nanofiltration membrane (UTC60 manufactured by Toray Industries, Inc.) The membrane permeate obtained through the functional surface material: polyamide) is concentrated using a reverse osmosis membrane (UTC80 manufactured by Toray Industries, Inc., functional surface material: polyamide) until the lactic acid concentration reaches 150 g / L. went. Thereafter, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. Table 9 shows the results of Reference Examples 10 and 11 as the evaluation of the crystallization process. As a result, it was found that no great difference was observed in the crystallization speed even when the film treatment was performed.

Example 1
The sugar solution obtained in Reference Example 5 is concentrated with an evaporator so that the glucose concentration is 50 g / L, fermented under the conditions of Reference Example 8, and the resulting fermentation solution is filtered with a filter press (MO manufactured by Iwata Sangyo Co., Ltd.). -4), solid-liquid separation was performed. The obtained fermentation filtrate turbidity was 5 NTU. Next, the ultrafiltration membranes having different fractional molecular weights by separating the fermentation filtrates (GE Osmonics GK (fractional molecular weight 3500, functional surface material: composite polymer mainly composed of polyamide), GH (fractional molecular weight 2500) , Functional surface material: composite polymer mainly composed of polyamide), GE (fraction molecular weight 1000, functional surface material: composite polymer mainly composed of polyamide), NTR7410 (fraction molecular weight 1000, manufactured by Nitto Denko Corporation) Functional surface material: sulfonated polysulfone) NTR7450 (fractionated molecular weight: 500 to 700, functional surface material: sulfonated polysulfone) was passed through the membrane permeate, reverse osmosis membrane (UTC80 manufactured by Toray Industries, Inc., functional surface material: Polyamide) until the lactic acid concentration becomes 150 g / L, and then the aqueous solution is adjusted to pH 7.0 for crystallization. Adding calcium to obtain calcium lactate aqueous solution. As the evaluation of the crystallization step of the thus obtained calcium lactate aqueous solution, Table 10 shows the results of Reference Examples 10 and 11.

(Comparative Example 1)
About the fermentation filtrate obtained by the filter press in Example 1, as it is (without membrane treatment), or an ultrafiltration membrane having a molecular weight cut off of 10,000 (GE Osmonics PW, functional surface material: polyethersulfone), the molecular weight cut off 5000 ultrafiltration membranes (SPE5 from Synder, functional surface material: polyethersulfone), nanofiltration membranes (UTC60 from Toray Industries, Inc., functional surface material: polyamide) and nanofiltration membranes (GE osmonics HL, functional surface materials: The membrane permeate obtained by passing through (polyamide) was subjected to concentration treatment in the same manner as in Example 1 until the lactic acid concentration reached 150 g / L. Thereafter, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. Table 11 shows the results of Reference Examples 10 and 11 as evaluation of the crystallization step of the obtained calcium lactate aqueous solution.

(Example 2)
The sugar solution obtained in Reference Example 6 is concentrated with an evaporator so that the glucose concentration becomes 50 g / L, fermented under the conditions of Reference Example 9, and the obtained fermentation solution is filtered with a filter press (MO manufactured by Iwata Sangyo Co., Ltd.). -4), solid-liquid separation was performed. The obtained fermentation filtrate turbidity was 7 NTU. Next, the ultrafiltration membranes having different fractional molecular weights by separating the fermentation filtrates (GE Osmonics GK (fractional molecular weight 3500, functional surface material: composite polymer mainly composed of polyamide), GH (fractional molecular weight 2500) , Functional surface material: composite polymer mainly composed of polyamide), GE (fraction molecular weight 1000, functional surface material: composite polymer mainly composed of polyamide), NTR 7450 (fraction molecular weight 500- The membrane permeate obtained through 700, functional surface material: sulfonated polysulfone) was concentrated using a reverse osmosis membrane (UTC80 manufactured by Toray Industries, Inc., functional surface material: polyamide) until the lactic acid concentration became 150 g / L. After that, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. As the evaluation of the crystallization step of the solution, shown in Table 12 The results of Reference Examples 10 and 11.

(Comparative Example 2)
The fermentation filtrate obtained by the filter press in Example 2 was used as it was (without membrane treatment), or an ultrafiltration membrane (GE osmonics PW, functional surface material: polyethersulfone) having a molecular weight cut off of 10,000, and a molecular weight cut off of 5000. Ultrafiltration membranes (SPE5 from Synder, functional surface material: polyethersulfone), nanofiltration membranes (UTC60 from Toray Industries, Inc., functional surface material: polyamide) and nanofiltration membranes (GE osmonics HL, functional surface material: polyamide) The membrane permeate obtained through the above was subjected to concentration treatment until the lactic acid concentration reached 150 g / L, as in Example 2. Thereafter, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. Table 13 shows the results of Reference Examples 10 and 11 as evaluation of the crystallization step of the obtained calcium lactate aqueous solution.

(Example 3)
The sugar solution obtained in Reference Example 7 is concentrated with an evaporator to a glucose concentration of 50 g / L, fermented under the conditions of Reference Example 9, and the obtained fermentation solution is filtered with a filter press (MO manufactured by Iwata Sangyo Co., Ltd.). -4), solid-liquid separation was performed. Next, the ultrafiltration membranes having different fractional molecular weights by separating the fermentation filtrates (GE Osmonics GK (fractional molecular weight 3500, functional surface material: composite polymer mainly composed of polyamide), GH (fractional molecular weight 2500) , Functional surface material: composite polymer mainly composed of polyamide), GE (fraction molecular weight 1000, functional surface material: composite polymer mainly composed of polyamide), NTR 7450 (fraction molecular weight 500- 700, functional surface material: sulfonated polysulfone)), and using a reverse osmosis membrane (UTC80 manufactured by Toray Industries, Inc., functional surface material: polyamide), the lactic acid concentration is 150 g / L. Concentration treatment was performed. Thereafter, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. Table 14 shows the results of Reference Examples 10 and 11 as evaluation of the crystallization step of the obtained calcium lactate aqueous solution.

(Comparative Example 3)
The fermentation filtrate obtained by the filter press in Example 3 was used as it was (without membrane treatment), or an ultrafiltration membrane having a fractional molecular weight of 10,000 (GE Osmonics PW, functional surface material: polyethersulfone), fractional molecular weight. 5000 ultrafiltration membranes (SPE5 from Synder, functional surface material: polyethersulfone), nanofiltration membranes (UTC60 from Toray Industries, Inc., functional surface material: polyamide) and nanofiltration membranes (GE osmonics HL, functional surface materials: The membrane permeate obtained by passing through (polyamide) was subjected to concentration treatment in the same manner as in Example 3 until the lactic acid concentration reached 150 g / L. Thereafter, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. Table 15 shows the results of Reference Examples 10 and 11 as evaluation of the crystallization step of the obtained calcium lactate aqueous solution.

(Example 4)
The sugar solution obtained in Reference Example 6 was subjected to solid-liquid separation using a filter press (MO-4 manufactured by Iwata Sangyo Co., Ltd.). Next, the enzyme was removed using an ultrafiltration membrane (PW made by GE Osmonics, functional surface material: polyethersulfone) having a molecular weight cut off of 10,000, and a reverse osmosis membrane (UTC70U, functional surface material: polyamide) manufactured by Toray Industries, Inc. The sugar solution was concentrated to 120 g / L. This solution was fermented under the conditions of Reference Example 9, centrifuged at 1500 G for 5 minutes, and further filtered using a microfiltration membrane (Millipore, functional surface material: polyvinylidene fluoride) having a pore size of 0.22 μm. Lactic acid bacteria were removed. Next, the ultrafiltration membranes having different fractional molecular weights by separating the fermentation filtrates (GE Osmonics GK (fractional molecular weight 3500, functional surface material: composite polymer mainly composed of polyamide), GH (fractional molecular weight 2500) , Functional surface material: composite polymer mainly composed of polyamide), GE (fraction molecular weight 1000, functional surface material: composite polymer mainly composed of polyamide), NTR 7450 (fraction molecular weight 500- 700, functional surface material: sulfonated polysulfone)), and using a reverse osmosis membrane (UTC80 manufactured by Toray Industries, Inc., functional surface material: polyamide), the lactic acid concentration is 150 g / L. Concentration treatment was performed. Thereafter, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. Table 16 shows the results of Reference Examples 10 and 11 as evaluation of the crystallization step of the obtained calcium lactate aqueous solution.

(Comparative Example 4)
The clear fermentation filtrate obtained by the microfiltration membrane treatment in Example 4 is used as it is (without membrane treatment) or an ultrafiltration membrane having a molecular weight cut off of 10,000 (GE Osmonics PW, functional surface material: polyethersulfone). , Ultrafiltration membrane with a molecular weight cut off of 5000 (SPE5 manufactured by Synder, functional surface material: polyethersulfone), nanofiltration membrane (UTC60 manufactured by Toray Industries, Inc., functional surface material: polyamide), nanofiltration membrane (HL manufactured by GE Osmonics) The membrane permeate obtained through the functional surface material (polyamide) was subjected to concentration treatment in the same manner as in Example 4 until the lactic acid concentration reached 150 g / L. Thereafter, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. Table 17 shows the results of Reference Examples 10 and 11 as evaluation of the crystallization step of the obtained calcium lactate aqueous solution.

(Reference Example 13) Crystallization of calcium lactate aqueous solution containing edible resource-derived impurities In order to confirm the effect of edible resource-derived impurities on the crystallization of organic acids or salts thereof, corn steep liquor (CSL, Oji Cornstarch Co., Ltd.) The test which obtains the crystal | crystallization of the lactic acid in (made) was done. CSL is centrifuged at 8000 G for 30 minutes, and further filtered using a microfiltration membrane (Millipore, functional surface material: polyvinylidene fluoride) with a pore size of 0.22 μm to remove solids, and a CSL filtrate is obtained. It was. Next, the CSL filtrates were divided into ultrafiltration membranes with no membrane treatment or different molecular weight cutoffs (GE Osmonics PW (fractional molecular weight 10,000, functional surface material: polyethersulfone), GK (fractional molecular weight 3500). , Functional surface material: composite polymer mainly composed of polyamide), GE (fraction molecular weight 1000, functional surface material: composite polymer mainly composed of polyamide)), or nanofiltration membrane (UTC60 manufactured by Toray Industries, Inc.) The membrane permeate obtained through the functional surface material (polyamide) was subjected to concentration treatment using a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.) until the lactic acid concentration reached 150 g / L. Thereafter, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. Table 18 shows the results of Reference Examples 10 and 11 as the evaluation of the crystallization process. As a result, it was found that the presence or absence of membrane treatment did not affect the crystallization rate of calcium lactate.

(Example 5)
Each of the fermentation filtrates obtained in Example 1 was divided into ultrafiltration membranes having different fractional molecular weights (GE Osmonics GK (fractional molecular weight 3500, functional surface material: composite polymer mainly composed of polyamide), GH ( Molecular weight cut-off 2500, functional surface material: composite polymer containing polyamide as a main component), GE (fraction molecular weight 1000, functional surface material: composite polymer containing polyamide as a main component), NTR7410 manufactured by Nitto Denko Corporation Membrane permeation solution was obtained by passing through molecular weight 1000, functional surface material: sulfonated polysulfone), NTR7450 (fractionated molecular weight 500-700, functional surface material: sulfonated polysulfone).

Next, each membrane permeate was subjected to ion exchange treatment to remove salt components in the solution. First, the strongly acidic cation exchange resin “DIAION SK1BH” (manufactured by Mitsubishi Chemical Corporation) was passed, and the passing solution was further passed through a strongly basic anion exchange resin “DIAION SA10AOH” (manufactured by Mitsubishi Chemical Corporation).

After ion exchange treatment of membrane permeate, water was evaporated at 80 ° C under reduced pressure (0.1 bar) using a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.). Then, lactic acid concentrates obtained from the respective membrane permeates were obtained. Thereafter, 60 mL of the lactic acid concentrate was divided into 10 mL · 6 and cooled to 15 ° C. over 6 hours at a cooling rate of 10 ° C./h. When the liquid temperature reached 40 ° C., 50 mg of lactic acid seed crystals were added to crystallize the lactic acid in the solution. The lactic acid crystals were obtained by solid-liquid separation by centrifugation from lactic acid concentrates divided every 10 mL every unit time (1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours) and then dried. Lactic acid crystal yields are shown in Table 19. The seed crystal was excluded from the yield.

(Comparative Example 5)
Fermentation filtrate obtained in Example 1 and ultrafiltration membrane (PW (fraction molecular weight 10000, functional surface material: polyethersulfone) manufactured by GE Osmonics, SPE5 (fraction molecular weight 5000, functional surface material: polyethersulfone)) The lactic acid concentrate was obtained by crystallization using an evaporator subjected to ion exchange treatment, concentration and crystallization according to Example 5, respectively. Lactic acid obtained by solid-liquid separation of lactic acid crystals by centrifugation from a lactic acid concentrate divided every 10 mL every unit time (1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours) The crystal yield is shown in Table 20. The seed crystal was excluded from the yield.

(Example 6)
Each of the fermentation filtrates obtained in Example 2 was divided into ultrafiltration membranes having different fractional molecular weights (GE Osmonics GK (fractional molecular weight 3500, functional surface material: composite polymer mainly composed of polyamide), GH ( Molecular weight cut-off 2500, functional surface material: composite polymer containing polyamide as a main component), GE (fraction molecular weight 1000, functional surface material: composite polymer containing polyamide as a main component), NTR7410 manufactured by Nitto Denko Corporation Membrane permeation solution was obtained by passing through NTR7450 (fraction molecular weight: 500 to 700, functional surface material: sulfonated polysulfone)). Ion exchange treatment of the membrane permeate, concentration after the ion exchange treatment, and crystallization were in accordance with Example 5. Lactic acid crystal yield obtained by solid-liquid separation of the lactic acid crystals from the concentrated lactic acid solution divided by 10 mL every unit time (1 hour, 2 hours, 3 hours, 4 hours, 5 hours) and then drying. Is shown in Table 21. The seed crystal was excluded from the yield.

(Comparative Example 6)
Fermentation filtrate obtained in Example 2 and ultrafiltration membrane (PW (fraction molecular weight 10000, functional surface material: polyethersulfone) manufactured by GE Osmonics, SPE5 (fraction molecular weight 5000, functional surface material: polyethersulfone)) Each of the membrane filtrates passed through was subjected to ion exchange treatment, concentration and crystallization according to Example 5. Every 10 mL per unit time (1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours). The yield of lactic acid crystals obtained by solid-liquid separation of the lactic acid crystals from the separated lactic acid concentrate by centrifugation and drying is shown in Table 22. The seed crystal content was excluded from the yield.

(Reference Example 14) Organic Acid Salt Crystallization of Ultrafiltration Membrane Concentrated Ultrafiltration Membrane (GE Osmonics SPE5 (fractionated molecular weight 5000, Functional surface material: polyethersulfone, membrane A), GK (fraction molecular weight 3500, functional surface material: composite polymer mainly composed of polyamide, membrane B), GE (fraction molecular weight 1000, functional surface material: polyamide) The composite polymer as a main component was treated with a film C)). In the membrane treatment, water was added to the non-permeation side to perform diafiltration treatment until the lactic acid concentration became 1 g / L or less. The UF membrane concentrates thus obtained from membranes A to C were designated as UF membrane concentrate A, UF membrane concentrate B, and UF membrane concentrate C, respectively. Reagents succinic acid, maleic acid or adipic acid (all manufactured by Wako Pure Chemical Industries, Ltd.) were added to UF membrane concentrates A to C and pure water (control) so as to be 30 g / L. Thereafter, calcium hydroxide was added to adjust the pH to 7.0 for crystallization to obtain an aqueous calcium lactate solution. As the evaluation of the crystallization step, the results relating to the calcium precipitates of the respective organic acids as in the case of the calcium lactate of Reference Example 10 are shown in Table 23.

(Reference Example 15) Organic Acid Crystallization of Ultrafiltration Membrane Concentrate In the same procedure as Reference Example 14, the reagents succinic acid, maleic acid, adipic acid (with UF membrane concentrate A to C and pure water (control) ( In each case, Wako Pure Chemical Industries, Ltd.) was added at 30 g / L. This was subjected to ion exchange treatment by the method described in Example 5, and then water was evaporated by evaporating water at 80 ° C. under reduced pressure (0.1 bar) using a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.). As a result of opening to the atmosphere when no longer observed, crystals were observed in each concentrated solution. After solid-liquid separation by centrifugation and drying, as shown in the “before cooling” column of Tables 24-26 Crystals of succinic acid, maleic acid and adipic acid were obtained. Thereafter, 60 g of each organic acid concentrate (including an organic acid solution and organic acid crystals) was divided into 10 g · 6 and cooled to 15 ° C. over 6 hours at a cooling rate of 10 ° C./h. When the liquid temperature reached 40 ° C., 50 mg of seed crystals of each organic acid (succinic acid, maleic acid, adipic acid) were added to crystallize the organic acid in the solution. Organic acid crystals are obtained by solid-liquid separation by centrifugation from organic acid concentrates divided every 10g per unit time (1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours) and then dried. The yield of organic acid crystals is shown in the column “before cooling” in Tables 24-26. The seed crystal was excluded from the yield.

The yield of each organic acid (succinic acid, maleic acid, adipic acid) obtained by solid-liquid separation of the obtained crystals by centrifugation and drying is shown in Tables 24-26. The crystal yield was calculated from the sum of the crystal components obtained during the concentration. A comparison between the case where the UF membrane concentrates B and C were added and the UF membrane concentrate A and the fermentation filtrate suggested that the components removed by the specific UF membrane treatment inhibited the crystal growth. That is, when succinic acid, maleic acid, and adipic acid were obtained by fermentation, it was found that problems similar to lactic acid occurred, suggesting that this is a common problem in fermentation using sugars derived from cellulose-containing biomass. It was done.

Reference Example 16 Succinic Acid Fermentation Method As a microorganism capable of producing succinic acid, succinic acid was fermented using Anaerobiospirillum succiniciproducens ATCC 53488 strain. 100 mL of liquid medium having the composition shown in Table 27 was placed in a 125 mL Erlenmeyer flask and sterilized by heating, and 20 sets thereof were prepared. In an anaerobic glove box, 1 mL of 30 mM Na ₂ CO ₃ and 0.15 mL of 180 mM H ₂ SO ₄ were added to each Erlenmeyer flask, and further comprised of 0.25 g / L cysteine · HCl and 0.25 g / L Na ₂ S. After adding 0.5 mL of the reduced solution, the microorganisms were inoculated, and the culture was allowed to stand at 39 ° C. for 24 hours to obtain 2 L of succinic acid fermentation broth.

(Example 7)
The sugar solution obtained in Reference Example 6 is concentrated with an evaporator so that the glucose concentration becomes 50 g / L, and the succinic acid fermentation solution obtained under the conditions of Reference Example 16 is filtered with a filter press (MO-4 manufactured by Iwata Sangyo Co., Ltd.). Were separated into solid and liquid. The concentrated sugar solution was not added because potassium, sodium, and magnesium, which are inorganic salts, were sufficient. The obtained fermentation filtrate turbidity was 7 NTU. Next, ultrafiltration membranes with different molecular weights divided by the fermentation filtrate (GE Osmonics GK (fractional molecular weight 3500, functional surface material: composite polymer mainly composed of polyamide), GE (fractional molecular weight 1000) The membrane permeate obtained through the functional surface material: a composite polymer composed mainly of polyamide) was subjected to concentration treatment with an evaporator until the concentration reached 70 g / L. Calcium hydroxide was added to adjust the pH to 7.0 to obtain a calcium succinate aqueous solution, and as an evaluation of the crystallization step of the obtained calcium succinate aqueous solution, lactic acid was converted to succinic acid by the methods of Reference Examples 10 and 11. Table 28 shows the results of evaluation in the form replaced with.

(Comparative Example 7)
The fermentation filtrate obtained by the filter press in Example 7 was used as it was (without membrane treatment), or an ultrafiltration membrane having a molecular weight cut-off of 5000 (SPE5 manufactured by Synder, functional surface material: polyethersulfone), nanofiltration membrane ( The membrane permeate obtained by passing through GE osmonics HL, functional surface material: polyamide) was subjected to concentration treatment until the succinic acid concentration reached 70 g / L as in Example 7. Then, calcium hydroxide was added so that it might become pH 7.0 for crystallization, and calcium succinate aqueous solution was obtained. As an evaluation of the crystallization step of the obtained calcium succinate aqueous solution, the results are shown in Table 29 in the form of replacing lactic acid with succinic acid by the methods of Reference Examples 10 and 11.

(Example 8)
Each of the fermentation filtrates obtained in Example 7 was divided into ultrafiltration membranes having different fractional molecular weights (GE Osmonics GK (fractional molecular weight 3500, functional surface material: composite polymer mainly composed of polyamide), GE ( A membrane permeation solution was obtained through a molecular weight cut-off of 1000, a functional surface material: a composite polymer mainly composed of polyamide), and NTR7450 (fractional molecular weight of 500 to 700, functional surface material: sulfonated polysulfone).

Next, each membrane permeate was subjected to ion exchange treatment to remove salt components in the solution. First, a strongly acidic cation exchange resin “DIAION SK1BH” (manufactured by Mitsubishi Chemical Corporation) is passed through the ion exchange resin, and the passing solution is further passed through a strongly basic anion exchange resin “DIAION SA10AOH” (manufactured by Mitsubishi Chemical Corporation). And the passing liquid was obtained.

After ion exchange treatment, water was evaporated at 80 ° C. under reduced pressure (0.1 bar) using a rotary evaporator (manufactured by Tokyo Rika Kikai Co., Ltd.), and when the water was no longer observed, the atmosphere was released to the atmosphere. A succinic acid concentrate obtained from the membrane permeate was obtained. As a result, crystals were observed in the concentrated liquid. Thus, solid-liquid separation was performed by centrifugation, followed by drying. As shown in Table 30, crystals of succinic acid were obtained. Thereafter, 60 g of the succinic acid concentrate was divided into 10 g · 6 and cooled to 15 ° C. over 6 hours at a cooling rate of 10 ° C./h. When the liquid temperature reached 40 ° C., 50 mg of succinic acid seed crystals were added to crystallize the succinic acid in the solution. Obtained by solid-liquid separation of succinic acid crystals by centrifugation from an organic acid concentrate divided by 10 g every unit time (1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours). The succinic acid crystal yield is shown in the column “before cooling” in Table 30. The seed crystal was excluded from the yield.

(Comparative Example 8)
The fermented filtrate obtained in Example 7 and the membrane filtrate passed through the ultrafiltration membrane (SPE5 (fractionated molecular weight 5000, functional surface material: polyethersulfone)) were each subjected to ion exchange treatment according to Example 8, A concentrated and crystallized evaporator was used to obtain 60 g of a succinic acid concentrate and crystallized. It was obtained by solid-liquid separation of succinic acid crystals by centrifugation from a lactic acid concentrate divided by 10 g every unit time (1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours) and then dried. The succinic acid crystal yield is shown in Table 31. The seed crystal was excluded from the yield.

From the comparison of the above Examples and Comparative Examples and Reference Examples, the organic acid fermentation broth obtained using the sugar derived from cellulose-containing biomass as the raw material exceeds that when the membrane treatment is performed with an ultrafiltration membrane having a fractional molecular weight of 3500 or less. Enables crystallization of organic acids or their salts, or significantly improves the crystallization rate of organic acids or their salts, compared to the case of membrane treatment with an ultrafiltration membrane with a molecular weight cutoff or no treatment. Was found. In addition, when organic acid fermented liquor obtained using sugar derived from cellulose containing biomass as a raw material is treated with a nanofiltration membrane, the organic acid permeation rate is low, indicating that the yield of the organic acid or its salt is poor. It was done.

Since the organic acid obtained by the present invention or a salt thereof is derived from non-edible biomass resources, it contributes to the escape from dependence on fossil resources.

Claims (8)

1. A step (1) of obtaining a membrane permeate by passing an organic acid fermentation broth using sugar derived from cellulose-containing biomass as a raw material through an ultrafiltration membrane having a fractional molecular weight of 3500 or less, and crystallizing an organic acid or a salt thereof from the membrane permeate The manufacturing method of the organic acid or its salt including the process (2) to analyze.
2. The method for producing an organic acid or a salt thereof according to claim 1, wherein the organic acid is lactic acid and / or succinic acid.
3. The method for producing an organic acid or a salt thereof according to claim 1 or 2, wherein the ultrafiltration membrane has a molecular weight cut-off of 1000 or less.
4. The organic permeate crystal is obtained by subjecting the membrane permeate in the step (1) to ion exchange treatment, and subjecting the obtained treatment solution to the step (2) to obtain an organic acid crystal. A method for producing an organic acid or a salt thereof.
5. The method for producing an organic acid or a salt thereof according to any one of claims 1 to 3, wherein an organic salt crystal is obtained by adding an inorganic salt or an aqueous solution thereof as the step (2).
6. The membrane permeation solution obtained in the step (1) is concentrated through a nanofiltration membrane or a reverse osmosis membrane, and then the step (2) is performed, according to any one of claims 1 to 5, A method for producing an organic acid or a salt thereof.
7. The method for producing an organic acid or a salt thereof according to any one of claims 1 to 6, wherein the functional surface of the ultrafiltration membrane is an organic material.
8. The method for producing an organic acid or a salt thereof according to claim 7, wherein the organic material contains polyethersulfone, polysulfone, sulfonated polysulfone, polyethylene glycol, polyamide or polyvinylidene fluoride.