阅读说明：本技术 二醇的制备方法 (Process for producing diol ) 是由 全商晙 南熙根 于 2018-04-26 设计创作，主要内容包括：在二醇的制备方法中,产生包含二醇的发酵培养液。对上述发酵培养液连续进行电渗析和离子交换处理,以产生去除杂质的预处理溶液。对上述预处理溶液进行纯化以获得二醇。(In a process for the production of a diol, a fermentation broth comprising the diol is produced. The above fermentation broth is continuously subjected to electrodialysis and ion exchange treatment to produce a pretreatment solution for removing impurities. The above pretreatment solution is purified to obtain a diol.)

1. A method for producing a diol, comprising the steps of:

Producing a fermentation broth comprising a diol;

Continuously performing electrodialysis and ion exchange treatment on the fermentation culture solution to generate a pretreatment solution for removing impurities; and

The above pretreatment solution is purified to obtain a diol.

2. The process for producing diols according to claim 1, wherein inorganic salts and organic acids contained in said fermentation broth are removed by said electrodialysis and ion exchange.

3. The process for producing diols according to claim 1 wherein the ion exchange comprises passing the fermentation broth through a cation exchange resin column and an anion exchange resin column in this order.

4. The process for producing diols according to claim 1 further comprising a step of filtering said fermentation broth before said electrodialysis and ion exchange treatment.

5. The process for producing diols according to claim 4 wherein the filtration comprises a continuous process of microfiltration and ultrafiltration.

6. The method of producing diols according to claim 5 wherein said microfiltration uses a polymer or ceramic membrane having a pore size of 0.05 to 10 μm.

7. The process for producing diols according to claim 5, wherein the ultrafiltration uses an organic polymer membrane or an organic hollow fiber laminate having a pore size in the range of molecular weight cut-off of 1,000 to 100,000.

8. The method of producing diols according to claim 5 wherein the cells and solids derived from microorganisms contained in the fermentation broth are removed by the microfiltration and the proteins are removed by the ultrafiltration.

9. The process for producing diols according to claim 5 wherein said electrodialysis and ion exchange treatment are continuously carried out immediately after said continuous microfiltration and ultrafiltration treatment.

10. The method of producing diols according to any one of claims 1 to 4 further comprising the step of concentrating the above pretreatment solution to remove moisture.

11. The process for producing diols according to claim 10 wherein said concentration comprises evaporation under reduced pressure to remove 90 to 95% of the water contained in said pretreatment solution.

12. The process for producing diols according to claim 1 wherein the step of purifying the pretreatment solution comprises distillation under reduced pressure.

13. The process for producing a diol according to claim 12, wherein the vacuum distillation comprises a first vacuum distillation and a second vacuum distillation, and the second vacuum distillation is carried out at a temperature higher than that of the first vacuum distillation.

14. The process for producing a diol according to claim 1, wherein the diol is 2, 3-butanediol.

15. The process for producing diols according to claim 1, wherein,

The step of producing the fermentation broth comprises:

A step of preparing a saccharified solution using a biological raw material; and

The strain is used in the above saccharification solution to produce a fermentation broth.

16. The method of claim 15, wherein the biological source comprises cassava and the strain comprises klebsiella.

Technical Field

The present invention relates to a method for producing diols, and more particularly, to a method for producing diols including separation and purification processes.

Background

For example, glycols such as 2,3-butanediol (2, 3-butaneediol) and the like are used as industrial preparations such as fuel additives, antifreezes, plasticizers and the like or household preparations such as cosmetics and pharmaceutical ingredients and the like. For example, the above-mentioned diols can be industrially produced by a continuous chemical catalytic process using C-4 olefins, but their use is limited due to problems such as expensive production processes, environmental pollution, and difficulty in separating isomers.

Recently, a process for producing 2,3-butanediol using low-cost and environmentally friendly 2,3-butanediol as a bio-base among processes for producing 2,3-butanediol has been developed and studied. Thus, the possibility of expanding the commercial availability of 2,3-butanediol is increasing. For example, 2,3-butanediol having a desired specific structure can be selectively produced by a bio-based process, and thus the use thereof can be also specifically developed.

However, in the process of producing the objective diol such as 2,3-butanediol, other diol by-products (for example, propylene glycol, 1, 3-butanediol, 1, 4-butanediol, etc.) can be produced simultaneously. In order to increase the yield of the objective diol, it is necessary to develop a separation and purification process.

Also, various impurities such as organic salts, inorganic salts, organic acids, etc. and bio-by-products such as microorganisms derived from biological raw materials, proteins, etc. may be generated together in addition to the diol by-product, and thus a process of removing the impurities and bio-by-products is required to be simultaneously performed.

For example, korean laid-open patent publication No. 1575717 discloses an example of a purification method of 2,3-butanediol including distillation under reduced pressure.

Disclosure of Invention

Technical problem

an object of the present invention is to provide a process for producing a diol which can produce a target diol in excellent yield and purity.

Means for solving the problems

1. A method for producing a diol, comprising the steps of: producing a fermentation broth comprising a diol; continuously performing electrodialysis and ion exchange treatment on the fermentation culture solution to generate a pretreatment solution for removing impurities; and purifying the pretreatment solution to obtain the diol.

2. The process for producing diols according to claim 1, wherein inorganic salts and organic acids contained in the fermentation broth are removed by the electrodialysis and ion exchange.

3. The process for producing a diol according to claim 1, wherein the ion exchange comprises passing the fermentation broth through a cation exchange resin column and an anion exchange resin column in this order.

4. The process for producing diols according to claim 1, further comprising a step of filtering the fermentation broth before the electrodialysis and ion exchange treatment.

5. The method for producing diols according to the above 4, wherein the filtration comprises a continuous treatment of microfiltration (micro-filtration) and ultrafiltration (ultra-filtration).

6. The method of producing diols according to the above 5, wherein the above microfiltration uses a polymer or ceramic membrane having a pore size of 0.05 to 10 μm.

7. The method for producing diols according to the above 5, wherein the ultrafiltration uses an organic polymer membrane or an organic hollow fiber laminate having a Molecular Weight Cut Off (MWCO) pore diameter in the range of 1,000 to 100,000.

8. The method of producing diols according to claim 5, wherein the cells and solids derived from microorganisms contained in the fermentation broth are removed by the microfiltration, and the proteins are removed by the ultrafiltration.

9. The method of producing a diol according to claim 5, wherein the electrodialysis and ion exchange treatment are continuously performed immediately after the continuous microfiltration and ultrafiltration treatment.

10. The method of producing diols according to any one of the above 1 to 4 further comprising the step of concentrating the above pretreatment solution to remove moisture.

11. The method for producing diols according to item 10 above, wherein the concentration comprises evaporation under reduced pressure to remove 90 to 95% of the water contained in the pretreatment solution.

12. The method for producing a diol according to claim 1, wherein the step of purifying the pretreatment solution comprises distillation under reduced pressure.

13. The process for producing a diol according to claim 12, wherein the reduced pressure distillation includes a first reduced pressure distillation and a second reduced pressure distillation, and the second reduced pressure distillation is performed at a temperature higher than that of the first reduced pressure distillation.

14. The process for producing a diol according to claim 1, wherein the diol is 2, 3-butanediol.

15. The method for producing a diol according to claim 1, wherein the step of producing the fermentation culture solution comprises: a step of preparing a saccharified solution using a biological raw material; and producing a fermentation broth using the strain in the above saccharification solution.

16. The method for producing diols according to claim 15, wherein the biological raw material comprises cassava (cassava) and the bacterial strain comprises Klebsiella (Klebsiella).

ADVANTAGEOUS EFFECTS OF INVENTION

According to an embodiment of the present invention, for example, before purifying a target diol by distillation under reduced pressure, pretreatment including electrodialysis and ion exchange may be performed to effectively remove components such as inorganic salts, organic acids, and the like present in a fermentation broth. Therefore, the purity of the objective diol can be significantly improved in the purification process.

Also, before the above-mentioned pretreatment including electrodialysis and ion exchange, a continuous treatment of microfiltration and ultrafiltration may be further performed. Therefore, biological by-products including cells, solids, proteins, etc. derived from microorganisms can be removed in advance before removing inorganic salts and organic acids, thereby improving pretreatment efficiency.

In addition, a specific raw material and strain having specificity to 2,3-butanediol may be used in the fermentation culture solution to reduce the production of other diols or alcohols in the step of preparing the fermentation culture solution, so that the recovery rate of 2,3-butanediol in the reduced pressure distillation step can be remarkably improved.

Further, the purity of the target diol can be further improved by combining the separation and purification step and the extraction step and/or the decoloring and deodorizing step.

Drawings

Fig. 1 is a schematic flow chart for explaining a method for producing a diol according to an exemplary embodiment of the present invention.

Fig. 2 is a schematic flow diagram illustrating a process for the preparation of glycols, which is some examples of the present invention.

Fig. 3 is a schematic flow diagram illustrating a process for the preparation of glycols, which is some embodiments of the present invention.

Fig. 4 is a schematic flow diagram illustrating a process for the preparation of glycols, which is some embodiments of the present invention.

Fig. 5 is a schematic flow diagram illustrating a process for the preparation of glycols, which is some embodiments of the present invention.

Detailed Description

Hereinafter, preferred embodiments are presented to more specifically describe the present invention. However, the examples given below are only intended to illustrate the present invention and those skilled in the art will clearly understand that various changes and modifications are possible within the scope and spirit of the present invention. Such changes and modifications are fully encompassed by the appended claims.

Fig. 1 to 3 are schematic flow charts for illustrating a method for producing a diol according to an exemplary embodiment of the present invention.

Referring to fig. 1, in the above method for producing diols, a fermentation broth containing a diol mixture is prepared (S10), impurities are removed (S20), the diol concentration is increased by concentration (S30), and the objective diol is obtained through a purification process (S40). In some embodiments, a decoloring or deodorizing process (S50) may be further optionally performed.

Preparation of fermentation broth (S10)

The fermentation broth can be obtained by fermenting a biological raw material using a strain. The biological material may be cereal (kernel), wood and/or starch based material. In an exemplary embodiment, as the above-mentioned bio-Raw material, a starch-based material may be used, and examples of the above-mentioned starch-based material may include starch-containing grains such as corn and rye, cassava (cassava), Raw sugar (Raw-sugar), glucose (glucose), and the like.

as the above-mentioned strain, a microorganism having a diol-containing fermentation product producing ability can be used without limitation. For example, Klebsiella (Klebsiella), Bacillus (Bacillus), Serratia (Serratia), Enterobacter (Enterobacter), Clostridium (Clostridium), yeast, escherichia coli (e.coli), and the like can be used as the microorganism.

The above-mentioned biological raw materials and strains can be selected in consideration of the desired target diol. In an exemplary embodiment of the present invention, the target diol may be 2, 3-butanediol. In one embodiment, the above-mentioned target diol may include 2R, 3S-butanediol among optical isomers of 2, 3-butanediol.

In some embodiments, cassava may be used as the above-described biological raw material, and klebsiella may be used as the above-described strain, in order to produce 2, 3-butanediol. For example, klebsiella oxytoca (k.oxytoca), klebsiella pneumoniae (k.pneumoniae), and the like can be used as the above strain, and klebsiella oxytoca (k.oxytoca) can be preferably used.

According to an exemplary embodiment, the above-described step of preparing the fermentation broth may include a saccharification process and a fermentation process of phase separation. The saccharification step may be performed in a liquid phase, for example, by pulverizing the biological raw material, mixing the pulverized biological raw material with a liquid such as fresh water, and adding a saccharifying enzyme to react with the biological raw material to prepare a saccharified solution. For example, the saccharifying enzymes can include amylase family enzymes.

Then, the strain is added to the saccharified solution to prepare a fermentation broth. For example, the fermentation broth may contain a monohydric alcohol and other glycols (e.g., ethylene glycol, diethylene glycol, 1, 3-propanediol, 1, 2-propanediol, dipropylene glycol, etc.) in addition to the target diol, 2, 3-butanediol. Also, the fermentation broth may include impurities such as various inorganic salts, organic acids, and biological by-products derived from the above strains or metabolites thereof.

As described above, by separately performing the saccharification step and the fermentation step, it is possible to relatively reduce the production of the biological by-product and improve the yield of the produced diol, for example, as compared with the case of performing the saccharification/fermentation simultaneously.

Removing impurities (S20)

The fermentation culture containing the biosynthetic diol may be subjected to an impurity removal step as a pretreatment step. Thus, the impurities contained in the fermentation broth can be removed.

As shown in fig. 2, the impurity removal process may include electrodialysis and ion exchange treatment (S25). In some embodiments, as shown in fig. 3, a filtering process (S23) may be further performed before the electrodialysis and ion exchange treatment (S25).

Filtration step (S23)

According to an exemplary embodiment of the present invention, the above-mentioned filtering process may include microfiltration (microfiltration) and ultrafiltration (utrafiltration). The biological by-products can be removed by passing the fermentation broth through a microfiltration membrane and an ultrafiltration membrane in succession.

for example, the microbial cells produced from the strain and the solid matter of the microorganism (floating solid matter or dissolved solid matter) can be removed by the above-mentioned microfiltration. The microfiltration may be performed by passing the fermentation broth through a polymer or ceramic membrane, for example, having a pore size of about 0.05 to 10 μm, installed in a filter module. The fermentation culture solution can be subjected to microfiltration repeatedly through a circulating channel. In one embodiment, the pore size of the microfiltration membrane may be about 0.05 to 0.2 μm.

After removing microbial cells and solid matter in the fermentation broth by microfiltration, proteins can be removed by ultrafiltration.

the ultrafiltration may be performed by passing the fermentation broth through an organic polymer membrane or an organic hollow fiber laminate, for example, having a pore size in the range of Molecular Weight Cut Off (MWCO) of 1,000 to 100,000, which is installed in a filter module.

As described above, cells and solids derived from the strain microorganism can be removed first and then proteins can be removed by continuous treatment of microfiltration and ultrafiltration. Therefore, the biological by-products are removed before the electrodialysis and ion exchange treatment, so that the fouling (fouling) caused by the biological by-products can be prevented, and the efficiency of the subsequent impurity removal process can be improved.

Also, for example, microfiltration/ultrafiltration can be used without employing a nanofiltration mechanism, thereby improving the specificity of the filtration process for biological byproducts. For example, if nanofiltration is used instead of a microfiltration/ultrafiltration continuous process, cells of microbial origin as well as solids and proteins can be removed simultaneously. Thereby, the filtration load is increased, so that the desired glycols can be coagulated or adsorbed onto the above-mentioned biological by-products and removed. Therefore, the yield of the target diol obtained after the purification step may be reduced.

However, according to the exemplary embodiment of the present invention, microfiltration and ultrafiltration, which are specifically designed according to the filtration target, are sequentially performed, thereby selectively removing only the above-mentioned bio-by-products, so that the efficiency and yield of the subsequent inorganic salt and organic acid removal process and the target diol purification process can be improved.

electrodialysis and ion exchange treatment (S25)

According to an exemplary embodiment of the present invention, a desalting process for removing inorganic salts and organic acids contained in the filtrate collected by the above-described microfiltration and ultrafiltration is performed by sequential continuous treatment of electrodialysis (electrodialysis) and ion exchange.

The above electrodialysis may be performed using a membrane unit comprising a cation exchange membrane and an anion exchange membrane. For example, a cation exchange membrane and an anion exchange membrane may be arranged between an anode and a cathode to divide the electrodialysis device into a plurality of compartments, and the above-described anode and cathode are used to supply a DC current.

For example, as Na⁺And K⁺Etc. monovalent cations and e.g. Ca²⁺And Mg²⁺Etc. divalent cations do not pass through the anion exchange membrane but are accumulatedAre collected in the compartment. Therefore, the filtrate from which inorganic salts such as metal salts are removed can be diluted in a desalted state and discharged.

The above filtrate from which the inorganic salts are removed can be subjected to ion exchange treatment, for example, to remove the organic acids.

The above filtrate subjected to the electrodialysis treatment may contain the objective diol and other alcohols, organic acids in the form of weak salts or weak ions. The organic acid present in the form of a weak salt or weak ion can be removed by the above-mentioned ion exchange treatment to obtain a pretreatment solution actually containing mainly the objective diol and other alcohols.

Examples of the ion exchanger used for the ion exchange treatment include ion exchange resins, ion exchange fibers, gel ion exchangers, liquid ion exchangers, zeolites, and carbonyl ion exchangers.

For example, an ion exchange treatment using both a cation exchange resin and an anion exchange resin may be performed. The above cation exchange resin can be regenerated into a weakly acidic solution such as hydrochloric acid or the like and used as the H form. The above anion exchange resin can be regenerated into a weakly basic solution such as sodium hydroxide and used as OH form.

The desalting method by the ion exchange resin may include a batch (batch) method or a column (column) method. According to an exemplary embodiment, the desalting may be repeated using a column method. For example, the filtrate subjected to the electrodialysis treatment may be passed through a cation exchange resin column and an anion exchange resin column in this order.

In a preferred embodiment, the above filtrate subjected to the electrodialysis treatment may be passed through a cation exchange resin column and then an anion exchange resin column. However, it is also possible to pass the above-mentioned filtrate subjected to the electrodialysis treatment through an anion exchange resin column first and then through a cation exchange resin column, and the embodiment of the present invention is not limited by the order of passing the columns.

According to exemplary embodiments, the inorganic salt may be removed by the above-described electrodialysis treatment, and the organic acid and the residual inorganic salt may be removed together by the above-described ion exchange treatment.

By sequentially and continuously performing electrodialysis and ion exchange, the efficiency of the desalting process of the filtrate from which the biological by-products are removed can be remarkably improved by the filtering process, and the selectivity and yield of the target diol obtained in the subsequent concentration and purification processes can be improved.

As described above, when a biological raw material (e.g., cassava) and a strain (e.g., klebsiella oxytoca) having specificity for 2,3-butanediol are used, a large amount of organic and inorganic impurities may be generated as compared to a general industrial production process or a biological process for producing other diols (e.g., 1, 3-propanediol).

Thus, when the above-mentioned organic and inorganic impurities are removed only by ion exchange, the load of the ion exchange process may excessively increase, and thus sufficient desalting efficiency may not be ensured. In addition, if the number of stages (e.g., the number of columns) in the ion exchange apparatus is excessively increased in order to ensure the required desalting efficiency, the process efficiency may be decreased, and the target glycol yield in the purification process may be deteriorated.

However, according to an embodiment of the present invention, the load of ion exchange can be reduced by performing electrodialysis prior to ion exchange. Therefore, the number of stages required for ion exchange can be designed to be, for example, a two-stage structure of cation exchange resin and anion exchange resin. Therefore, it is possible to prevent the decrease in the target diol yield due to the increase in the number of ion exchange stages and to ensure the desired desalting efficiency.

Concentration (S30)

The water of the pretreatment solution subjected to the electrodialysis and ion exchange treatment can be removed by concentration. For example, the concentration can be carried out by a reduced pressure Evaporation (Vacuum Evaporation) process. The removal ratio of water by the above-described concentration process may be set in consideration of the efficiency of the subsequent purification of the target diol and the extraction process to be described below. If the water removal rate is too high, the efficiency of the above extraction process is reduced. Also, if the removal ratio of water is too low, the efficiency of the purification process is lowered, and thus the yield of the target diol may be lowered.

For example, about 90 to 95% of the water contained in the pretreatment solution can be removed by a concentration step. In one embodiment, the concentration of the fermentation product in the culture solution can be adjusted to about 500 to 900g/L by the above-mentioned concentration step.

Purification of the target diol (S40)

The concentrated solution including the fermentation product may be collected by a concentration step, and the target diol may be obtained from the concentrated solution by a purification step.

According to an embodiment of the present invention, the purification process may include distillation. For example, the distillation step may include single distillation, atmospheric distillation, thin film distillation, vacuum distillation, and the like. In some embodiments, a reduced pressure distillation procedure may be employed for the purification of the target diol. The boiling point is lowered by distillation under reduced pressure, whereby the generation of impurities in the distillation step can be suppressed.

In some embodiments, the purification process may include a first vacuum distillation and a second vacuum distillation.

The second reduced pressure distillation may be performed at a higher temperature than that of the first reduced pressure distillation. For example, the above-described first reduced pressure distillation may be performed at a temperature ranging from about 40 to 70 degrees (. degree. C.) to discharge impurities having a boiling point lower than that of the target diol (e.g., 2,3-butanediol) to the top (top). The second reduced pressure distillation of the concentrate including the target diol may be performed at a temperature ranging from about 100 to 130 degrees (c).

if the second reduced pressure distillation temperature is less than about 100 degrees, the recovery rate may be reduced. If the second reduced pressure distillation temperature exceeds about 130 degrees, it may react with the target diol (e.g., 2,3-butanediol) or remaining trace organics to produce byproducts.

Decolorizing or deodorizing (S50)

In the examples of the present invention, a decoloring or deodorizing process is further selectively performed according to the use of the objective diol. For example, when 2,3-butanediol is used as a component of a cosmetic or a cosmetic composition, a decoloring or deodorizing step may be further performed.

Extraction procedure (S32)

Fig. 4 is a schematic flow diagram illustrating a process for the preparation of glycols, which is some embodiments of the present invention. For example, as shown in fig. 4, the remaining impurities may be additionally removed by further performing an extraction process.

In some embodiments, the extraction process described above may be performed between concentration processes. For example, the extraction process may be performed on the pre-treatment solution partially removed of water by the first concentration process (S31), and then the extraction solvent used in the extraction process may be recovered by the second concentration process (S35).

The extraction step may include solvent extraction (or solvent precipitation), aqueous extraction of foreign components, phase separation extraction, and the like. The solvent extraction described above may include, for example, a mechanism of precipitating impurities using an extraction solvent. For example, the above-described aqueous heterogeneous extraction may include a mechanism to separate and remove impurity phases by adding inorganic salts. For example, the phase separation extraction described above may include a mechanism to increase the yield of the target diol by separating an organic phase and an inorganic phase.

In exemplary embodiments of the present invention, a solvent extraction process may be used in consideration of convenience in preventing residues and recovery processes due to the addition of additional components in the extraction process, and the like.

For example, as the extraction solvent, a lower alcohol solvent may be added to the pretreated solution having undergone the first concentration step. For example, the inorganic salt and the organic acid salt that are not removed by the impurity removal step (S20) with the aid of the extraction solvent form a precipitate in a solid form.

As the above-mentioned extraction solvent, a lower alcohol having 3 or less carbon atoms can be used for separation from a target diol such as 2, 3-butanediol. For example, methanol, ethanol and/or isopropanol may be used as the above extraction solvent, and preferably, isopropanol may be used.

The pretreatment solution subjected to the extraction process may be filtered to remove the precipitate. Thereafter, the extraction solvent may be recovered through the second concentration step (S35). The recovered extraction solvent may be recycled for re-addition to the extraction process.

Additional recovery step

Fig. 5 is a schematic flow diagram illustrating a process for the preparation of glycols, which is some embodiments of the present invention. For example, the residue produced after the purification of the target diol is subjected to an additional recovery step. As shown in fig. 5, the residue is washed with a solvent (S45), and the washed residue is recycled to, for example, the extraction process (S32) or the second concentration process (S35), so that the purification of the target diol can be repeated.

In one embodiment, the solvent wash described above may be performed by a mechanism substantially the same as or similar to the extraction procedure described above. For example, the above residue may be washed with a solvent comprising isopropanol, and the precipitate is removed by filtration, and then the washed residue may be recycled.

In some embodiments, the washed residue may be recycled to the extraction process (S32), and the above-described solvent extraction process may be performed again. In some embodiments, the above-mentioned residue after washing may be recycled to the second concentration process (S35) to remove the solvent by distillation under reduced pressure, and then the target diol may be recovered through the purification process (S40). In some embodiments, the washed residue may be added directly to the target diol purification process (S40).

In some embodiments, after the decolorizing/deodorizing (S50), the residue produced in the form of a sludge or cake, for example, may be further recovered. As shown in fig. 5, the decolorized/deodorized residue is washed with a solvent (S45), and then the product is recycled through extraction, concentration, and/or purification processes.

Hereinafter, the procedures of the method for producing a diol according to the example of the present invention will be described in detail with reference to specific experimental examples. Examples and comparative examples included in the experimental examples are only intended to illustrate the present invention and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention. Such changes and modifications are fully encompassed by the appended claims.

Examples of the experiments

1) Preparation of fermentation broth

Cassava as a raw material was pulverized and then saccharified to be used as a carbon source, and a fermentation broth containing 2,3-butanediol as a target diol was prepared using klebsiella oxytoca (k.oxytoca) GSC112LK strain. Specifically, 1mL of Klebsiella oxytoca (K.oxytoca) GSC112(KCTC11888BP) LK strain stored in a 15% glycerol solution at-70 ℃ was inoculated into 20mL of a mixed medium containing 10g/L of a saccharified material and cultured at 37 ℃ and 150rpm for 8 hours. 3.0mL of each of the prepared culture liquids was transferred to 300mL of a mixed medium containing 10g/L of a saccharified raw material, and cultured again at 37 ℃ and 150rpm for 8 hours.

The LK strain is a strain from which the ldhA gene encoding lactate dehydrogenase (lactate dehydrogenase) involved in the production of lactic acid by the strain has been removed. 300mL of the culture solution cultured as described above was inoculated into a bioreactor containing 2.7L of a mixed medium containing 10g/L of the raw material and subjected to fermentation. The culture conditions were as follows: 300mM saccharified material, 37 ℃ incubation temperature and 150rpm stirring speed.

The previously measured absorbance (OD600), the gravimetric line of stem cells and the spectrophotometer were used to estimate the cell concentration during the culture. The concentrations of various organic acids including succinic acid and other alcohols produced as metabolites during the culture were periodically sampled from the bioreactor, and centrifuged at 13,000rpm and 4 ℃ for 10 minutes, and then the supernatant was analyzed by liquid chromatography (HPLC).

As a result, as shown in Table 1, a fermentation broth containing about 120g/L of 2,3-butanediol as the objective diol was obtained as a final product.

TABLE 1

Classification	2,3-butanediol	Formic acid	Ethanol	Lactic acid	Succinic acid	Acetic acid	Acetoin
								Content (g/L)	120.1	3.88	0.92	0.17	0.21	4.56	3.98

2) Filtration step

2-1) micro-filtration (micro-filtration)

The fermentation broth is first passed through a microfiltration membrane having a pore size of 0.05 μm at a system pressure of 2 to 3bar and a temperature of 30 to 40 ℃ at a flow rate of 25L/m 2/h.

2-2) Ultrafiltration (ultra-filtration)

The microfiltered broth was continuously passed through an ultrafiltration membrane in the form of a MWCO 10,000 hollow fiber. The system temperature and pressure were maintained at 30 to 40 ℃ and 5 to 6bar, respectively. The flow rate of the culture solution was maintained at 20L/m²/h。

After the microfiltration, about 99% or more of the total amount of cells and solids contained in the fermentation broth is removed, and after the ultrafiltration, about 70% of the protein in the fermentation broth is removed. The amount of protein removed was obtained by Bradford protein quantitation method (Bradford assay).

3) Electrodialysis (electrodialysis) and ion exchange treatment

Introducing the fermentation broth subjected to the microfiltration and ultrafiltration into an electrodialysis device, wherein the electrodialysis device is filled with a cation exchange resin membrane and an anion exchange resin membrane and comprises three compartments. 180VDC power was applied to the anode and cathode and the flow rate in the compartment was maintained at 60 to 80LPM (L/min).

Continuously carrying out ion exchange on the culture solution after electrodialysis. Specifically, a weakly basic anion exchange resin and a strongly acidic cation exchange resin were packed in a column, and the culture solution subjected to the electrodialysis treatment was passed through the cation resin and the anion resin at room temperature in this order by a pump at 5 LPM. The composition of the pretreatment solution after the electrodialysis and ion exchange treatment (pretreatment) was analyzed by HPLC and IC, as shown in Table 2 below.

TABLE 2

Referring to table 2, about 95% or more of the organic acids were removed by the successive treatments of electrodialysis and ion exchange, and about 90 to 99% or more of the ions/salts were also removed.

On the other hand, when the ion exchange treatment was performed under the same conditions except that the electrodialysis was omitted, the concentration of the final ionic component reached a similar level, but when the same amount of resin was used, the fermentation broth treatment amount was reduced to 50% or less. Therefore, in this case, the regeneration waste water increases as the operation lot increases, and the dilution factor of 2,3-butanediol for achieving the same recovery rate must be increased.

4) Concentrating

The pre-treatment solution subjected to the electrodialysis and ion exchange treatment was subjected to evaporation under reduced pressure at 50 ℃ and 50mbar to prepare a glycol concentrate of 50 weight percent or more with 90% of water removed.

5) Purification of the target diol

The concentrate is subjected to a first reduced pressure distillation at 50mbar and 40 ℃ to remove impurities having a boiling point below that of 2, 3-butanediol. Subsequently, 2,3-butanediol was recovered by a second reduced pressure distillation at a pressure of 50mbar and 105 ℃.

As a result of the above purification, 2,3-butanediol having a purity of 99.5% was obtained at a recovery rate of about 85% with respect to the fermentation broth.