KR20060083729A - Purification methods for succinic acid - Google Patents

Abstract

The present invention relates to a method for efficiently purifying high purity succinic acid from a fermentation broth in which a large amount of succinic acid is expressed using a strain, and more specifically, an extraction process, a reduced pressure evaporation process, and a crystallization process may be selectively performed. Or it relates to a method of obtaining succinic acid of high purity by performing sequentially. According to the present invention, it is possible to solve the problems of the conventional succinic acid production by the chemical synthesis method and the conventional organic acid purification method, it is possible to produce succinic acid with high efficiency and low cost. Succinic acid produced by the present invention may be usefully used in biodegradable polymers, food, pharmaceuticals, cosmetics industry, and the like.

Succinic acid, extraction, vacuum evaporation, crystallization, succinic acid fermentation strain (Mannheimia succiniciproducens)

Description

Purification methods for succinic acid             

1 is a flow chart of a method for separating succinic acid from fermentation broth.

Figure 2 shows the results of HPLC analysis after the vacuum evaporation-crystallization step (pH 2.0).

3 is an HPLC analysis result after sequentially performing an extraction step (once) -pressurization evaporation step-crystallization step (pH 2.0).

The present invention relates to a method for efficiently purifying high purity succinic acid from a fermentation broth in which a large amount of succinic acid is expressed using a strain, and more specifically, an extraction process, a reduced pressure evaporation process, and a crystallization process may be selectively performed. Or it relates to a method of obtaining succinic acid of high purity by performing sequentially.

Organic acids, including succinic acid, are widely used in the plastics, food, medicine and cosmetic industries. In particular, succinic acid has been increasingly used as a monomer of biodegradable polymers that can overcome the difficulty of biodegradation, which is a weak point of synthetic polymers, which has been actively produced with the development of petrochemical industry (Kirk O., Encyclopedia). of Chemical Technology, 3rd ed., 21 John Wiley & Sons, 1979; Gottschalk G., B acterial Metabolism, 2nd ed., Springer-Verlag, NY USA, 1986). That is, about one third of the synthetic polymers currently used are used as products used in relatively short periods of time, such as once-packed containers, and thus, environmental pollution caused by these wastes is seriously raised. Recently, researches to replace the synthetic polymers with biodegradation have been actively conducted, and biodegradable aliphatic polyester polybutylene succinate is attracting attention as a next-generation biodegradable polymer, and economical purification process for succinic acid as its main raw material is also urgently needed. (See: Takiyama E. and Fujimaki T., Biodegradable plastics and polymers, 150-176, 1994; Maeda Y., Nakayama A., Kawasaki N., Hayashi K., Aiba S., Yamamoto N., J Environ.Polym.Degr., 4: 225-223, 1996).

However, the production cost of succinic acid through biological process is much higher than the conventional chemical synthesis process, the biggest reason is that the process of purifying succinic acid from fermentation broth is inefficient. Due to these factors, most succinic acids are produced by chemical processes using hydrogenation and hydration reactions based on maleic anhydride (see, eg, Glassner DA, Elankovan P., Beacom DR, Berglund KA, Appl. Biochem). Biotech., 51 (2): 73-82, 1995).

The fermentation broth contains many impurities resulting from fermentation, and the removal of these impurities has a great effect on the economics and practical use of the products produced by fermentation. It is known that the cost of the separation and purification process in the production of succinic acid using fermentation process is about 40% to 70% (King C.J., Chemtech, 22 (5): 285-291, 1992).

To date, known methods for purifying organic acids containing succinic acid from fermentation broth include filtration-precipitation, crystallization, liquid-liquid extraction, membrane separation, and reaction distillation using esterification. Let's see.

The filtration-precipitation method is based on precipitating calcium salt by adding Ca (OH) ₂ to the fermentation tank in the aqueous phase. The solids are filtered and the remaining liquid organic acids are purified, crystallized and separated. However, it has the disadvantage that crystallization efficiency is very low and crystallization is difficult (see Vick Roy TB, Integral Biotechnology, Murray Moo-Young eds., Vol. 3, Pergamon Press, 761, 1985; Bessling B., Loening JM, Ohligschlaeger A., Schembecker G. and Sundmacher L., Chem. Eng. Technol., 21: 393-400, 1998).

The liquid-liquid extraction process first extracts the organic acid with a solvent such as isopropyl ether, diethyl ether, isoamyl alcohol and the like. The extracted organic acid is recovered from the solvent through a method such as back extraction or distillation (Korea Patent Publication No. 0006664, Japanese Patent No. 1037851, etc.). In general, the organic acid molecules have a low activity against water, that is, the organic acid molecules have higher solubility in water than organic solvents, and thus the method is not very effective (Han DH and Hong WH, Sep. Sci. & Techn., 31: 1123-1135, 1996).

A typical process of membrane separation is electrodialysis. Electrodialysis is the most actively studied method, which is based on the electrical movement of ions using exchange membranes that allow the passage of cations or anions. It has advantages such as rapid treatment, removal of non-ionic molecules, and non-product formation, and recently, various membrane processes such as precision, ultrafiltration, nanofiltration and reverse osmosis have been used in connection with electrodialysis (Korea Patent No. 0067316, European Patent Publication No. 0393818, etc.). However, the ion exchange membrane in the electrodialysis device is not only expensive equipment, but also can be contaminated and form scale when used for a long time. Due to the problem, it has not been used until the practical stage (see Lee EK, "Recovery of lactic acid from fermentation broth using electrodialysis", KAIST Ph.D. Thesis, 1998, Zeikus JG, Elankovan P. and Grethlein A., Chem. Proc., 58 (7): 71-73, 1995).

Reaction distillation using esterification is a method of obtaining a high purity organic acid, selectively reacting a low-molecular alcohol with an organic acid, separating the ester formed through distillation, recovering the organic acid through hydrolysis, which is a reverse reaction, and reusing the produced alcohol. That's how. The organic acid obtained by this method has almost no impurities and has an advantage of excellent thermal stability. However, this method has the disadvantage that the steps are complicated and the equipment cost is high accordingly (see Choi J. and Hong WH, Int. J. of Chemical Kinetics, 28: 37-41, 1996; Choi J. and Hong WH). , J. of Chemical Eng. Of Jpn., 32 (2): 184-189, 1999).

In addition, the above studies on the organic acid purification method described above have a problem in that monovalent carboxylic acids such as lactic acid and acetic acid are relatively easy to be purified.

The present invention is to solve the above problems, to implement a succinic acid purification method that can improve the problems of the production of succinic acid by the conventional chemical synthesis method and the existing organic acid purification method.

In order to achieve the above object, the present invention is made by centrifuging the fermentation broth with a large amount of succinic acid using a strain to take a supernatant, and then selectively or sequentially performing an extraction process, a reduced pressure evaporation process and a crystallization process.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

1 is a flowchart showing a purification method according to the present invention.

In the present invention, the strain for succinic acid fermentation was used in Mannheimia succiniciproducens, which recently analyzed the physiological succinic acid production metabolic circuit and established optimal fermentation conditions. However, the present invention is not limited to the fermentation broth by the above strains, but is also applied to the fermentation broth by all strains expressing succinic acid in addition to the above strains.

The fermentation broth induced to express a large amount of succinic acid is present with not only succinic acid but also several impure organic acids and salts. The fermentation broth expressed by the strain Mannheimia succiniciproducens expresses not only succinic acid but also several impurity organic acids, such as dermal acid, acetic acid, malic acid and fumaric acid.

The extraction process is performed using an amine extractant. The extraction process in the present invention uses a long chain tertiary amine, which forms a complex of an amine and an organic acid and separates it into an organic phase. Extraction using such an amine utilizes the basicity of the amine, and is achieved by reacting with an organic acid to form a salt. Compared with other purification methods, the extraction process of the present invention can minimize the consumption of chemicals by recycling the organic solvent through back extraction after extraction, and shows high selectivity and extraction efficiency. In addition, since it is carried out at room temperature and atmospheric pressure, it has the advantage of saving energy than conventional purification methods.

The reduced pressure evaporation process is performed in a predetermined temperature range to remove the relatively low boiling organic acid.

The crystallization process is performed at predetermined pH and temperature conditions.

Hereinafter, the present invention will be described in detail by preferred examples and test examples according to the present invention.

Example 1 Purification of Succinic Acid by Extraction Process

After centrifugation of the fermentation broth by Mannheimia succiniciproducens strain, 100 ml (dry weight: 6.92 g) of the supernatant was taken. Long chain tertiary amine was mixed with the supernatant. The supernatant and tertiary amine were mixed to 1: 1. After adjusting to pH 5.0, extraction was performed at room temperature for 30 minutes. After extraction, phase separation was performed at 4,000 rpm for 5 minutes using a centrifuge. With the above process as 1 cycle, 3 cycles were performed continuously to purify succinate.

Test Example 1 Analysis of Composition and Efficiency after Performing Extraction Process

After performing the extraction process according to Example 1 was analyzed with a UV / Visible detector (Waters 2487) through HPLC (Supelcogel C-610H, 300 mm 7.8 mm, Supelco, USA) using an organic acid column, the results are shown below Table 1 shows. As standards, succinic acid (99.9%, Sigma), pyruvic acid (99.9%, Sigma), acetic acid (99%, Juncei), malic acid (Aldrich), fumaric acid (99.5%, Fluka) were used. The concentration of glucose was analyzed by using the Glucose anaylzer (YSI 2700, USA) , the dry weight of each sample was determined by using a freeze-drier (Freeze dryer, I lShin Lab Co. , Korea).

[Table 1] Composition after extraction process

As shown in Table 1 above, it was confirmed that the impurity organic acids were effectively removed through the extraction process. In case of succinic acid, there was no difference between before and after extraction process (supernatant 2.23g, after 3 cycle extraction process: 2.22g). However, various impurity organic acids (pyruvic acid, acetic acid, malic acid, fumaric acid, unknown sample) can be effectively removed through the extraction process (supernatant: 1.27g, after 1 cycle extraction process: 0.745g, 2 cycle extraction process) After execution: 0.654g, after 3 cycle extraction process: 0.594g).

 Table 2 below shows that as the number of extractions is increased (as the number of cycles is increased), impure organic acids are more effectively removed. However, the overall increase in the extraction efficiency of impurity organic acids decreased as the number of extraction times increased. The extraction efficiency increased by 41.34%, 7.16%, and 4.75% compared with the previous step. Therefore, in terms of economics, the optimal cycle of extraction is one time.

[Table 2] Removal Efficiency of Impurity Organic Acids According to the Number of Extraction Processes

Example 2 Purification of Succinic Acid by Depressurization

The fermentation broth by Mannheimia succiniciproducens strain was centrifuged and 100 ml (dry weight: 6.92 g) of the supernatant was taken. The supernatant was evaporated under reduced pressure under a temperature of 90 ° C. to purify succinic acid.

Test Example 2: Decompression evaporation Analysis of composition and removal efficiency after process

After performing the reduced pressure evaporation process according to Example 2, the analysis was carried out under the same apparatus and conditions as in Test Example 1, and the results are shown in Table 3 below.

[Table 3] Composition and Removal Efficiency after Pressure Reducing Evaporation Process

As shown in Table 3, the removal efficiency of acetic acid 55.6%, malic acid 37.5%, pyruvic acid 14.3% was obtained.

Example 3 Purification of Succinic Acid by Vacuum Evaporation-crystallization

After the reduced pressure evaporation step of Example 2, a crystallization step was further performed. The obtained product, which was subjected to a reduced pressure evaporation process, was left at various pH conditions (1.0 to 3.0) at a temperature of about 4 ° C. for 12 hours to carry out a crystallization process to purify succinic acid.

Test Example 3 Composition Analysis after Decompression Evaporation Process

After performing the process according to Example 3, the analysis was performed under the same apparatus and conditions as in Test Example 1, and the results are shown in Tables 4 and 5 below.

[Table 4] Composition after decompression evaporation process

[Table 5] Yield and purity of succinic acid according to pH change

As shown in Table 4 and Table 5, when combined with a reduced pressure evaporation process-crystallization process, it was possible to remove more than 95% of the impure organic acid at all pH conditions, and to remove more than 99.8% of glucose. As can be seen from the table, the yield of succinic acid was increased while the pH was lower, but the purification effect was decreased, and the opposite phenomenon was observed at high pH. This is generally due to the lower pH solubility of the organic acid, the non-acidic acid properties as well as the properties of the monomer organic acids are bonded to each other by hydrogen bonds and crystals are large. In view of comprehensive analysis of the above table in consideration of both aspects of yield and purity, it is determined that the condition of pH 2 is most preferable. 2 is a result of HPLC analysis of the composition according to the present example under conditions of pH 2. As shown in the figure, the peaks of most of the impure organic acids have been largely removed, and it can be seen that high purity organic acids are purified.

Example 4 Purification of Succinic Acid by Extraction Process, Depressurization Evaporation Process, and Crystallization Process

After performing the extraction cycle of 1 cycle according to Example 1, the vacuum evaporation process was carried out, and then succinic acid was purified by performing a crystallization process under the condition of pH 2.0.

Test Example 4 Composition Analysis after Extraction Process, Pressure Evaporation Process, and Crystallization Process

After performing the process according to Example 3, the analysis was carried out under the same apparatus and conditions as in Test Example 1, and the results are shown in Table 6 below.

[Table 6] Composition and yield after extraction process-pressure evaporation process-crystallization process

As shown in the above table, it can be seen that succinic acid having high purity (99.76%) and high yield (73.09%) can be obtained when the extraction process, the pressure reduction evaporation process, and the crystallization process are performed continuously. Comparing the above results with those of Example 3, which excludes the extraction process, it can be seen that when the extraction process is preceded, higher yield and higher purity succinic acid are obtained. 3 is a result of HPLC analysis of the composition according to the present example. As shown in the figure, the peaks of most of the impure organic acids are almost removed, and it can be seen that the organic acids having high purity are purified.

As described above, according to the present invention, it is possible to solve the problems of the conventional succinic acid production by the chemical synthesis method and the conventional organic acid purification method, and according to the present invention enables the production of succinic acid at high efficiency and low cost. do. Succinic acid produced by the present invention may be usefully used in biodegradable polymers, food, pharmaceuticals, cosmetics industry, and the like.

Claims (5)

In the method of purifying succinic acid from the fermentation broth expressed using the strain, Succinic acid purification method characterized in that the extraction process, reduced pressure evaporation process, crystallization process selectively or sequentially The method of claim 1, The extraction step is a succinic acid purification method characterized in that carried out using an amine extractant The method of claim 1, The crystallization process is succinic acid purification method characterized in that carried out in the range of pH 1.0 to 3.0 The method of claim 3, Succinic acid purification method characterized in that the pH is 2.0 The method according to any one of claims 1, 3, and 4, The succinic acid purification method characterized in that the crystallization process is made in a temperature range of 0 ~ 10 ℃

Images