KR102572617B1 - Method of preparation of 3-hydroxypropionic acid - Google Patents

Abstract

The method for producing 3-hydroxypropionic acid according to the present invention has an effect of minimizing the process of exposure to strongly acidified fermentation broth due to essential acid treatment in extracting 3-hydroxypropionic acid from the culture medium.

Description

Method for preparing 3-hydroxypropionic acid {Method of preparation of 3-hydroxypropionic acid}

The present invention relates to a method for producing 3-hydroxypropionic acid, which can minimize the process cost of exposure to an acidified fermentation broth due to essential acid treatment in extracting 3-hydroxypropionic acid from a culture broth.

3-hydroxypropionic acid (3-HP) is a synthetic intermediate that can be used in various chemical processes. It is an industrially important compound used as a raw material for the synthesis of various compounds such as propionic acid, malonic acid, propionlactone, and acronitrile.

3-HP can be produced by a pure chemical process, but recently, it is produced by a separation and purification process from a low concentration (<10 wt%) 3-HP culture medium produced by a microorganism-based fermentation process. For such separation and purification, liquid-liquid extraction or reactive extraction techniques are generally used instead of water evaporation, which requires a lot of energy.

In particular, 3-HP is mainly ionized into carboxylate (COO ^- ) in ^the fermentation broth and exists in the form of a salt combined with calcium ion (Ca ²⁺ ). For this reason, after filtering and removing impurities from the fermentation broth, 3-HP having a pKa of 4.51 can be reduced to a carboxylic acid form by adding a strong acid such as sulfuric acid to the fermentation broth to lower the pH to 1 to 2. Since the carboxylic acid form is easier to extract than the ionic form, a method of improving the extraction efficiency of 3-HP by acid-treating the fermentation broth before separation and purification is used.

However, the extraction method of 3-HP using the above acid treatment has several problems. First, in the process of mixing the acid and the fermentation broth for acid treatment and extracting 3-HP from the fermentation broth, special steel materials are used so that the mixing tank and reactor (or extractor) can withstand strong acid for a long mixing time. Process costs increase. For example, among currently commercialized reactor materials, a reactor that can withstand a strong acid of about pH 2 is 2 to 5 times more expensive than a reactor that can withstand a weak acid of about pH 4. In particular, since 3-HP extraction requires a long reaction in a reactor, strong acid conditions should be avoided in the process as much as possible in order to lower process equipment costs.

Therefore, as will be described later, the present inventors divided the acid treatment process into two steps, adjusting the pH of the culture medium to a weak acid level in the previous step of the extraction process, and then extracting 3-HP and then adding additional acid to the filtrate to be recycled as a fermentation broth. The present invention was completed by confirming a 3-HP manufacturing method capable of reducing process equipment costs by subjecting to processing.

The present invention is to provide a method for producing 3-hydroxypropionic acid, which can minimize the process of exposure to strongly acidified fermentation broth due to essential acid treatment in extracting 3-hydroxypropionic acid from a culture broth.

In order to solve the above problems, the present invention provides a method for preparing 3-hydroxypropionic acid, comprising the following steps:

Adjusting the pH of the fermentation broth containing 3-hydroxypropionic acid to 3.5 to 5.5 (step 1);

recovering an extract containing 3-HP by adding an extraction solvent to the fermentation broth of step 1 and performing phase separation (step 2); and

Adjusting the pH of the filtrate of step 2 to 1.5 to 2.5 to remove residual impurities in the filtrate (step 3).

Hereinafter, the present invention will be described in detail for each step.

(Step 1)

Step 1 is a step of adjusting the pH of the fermentation broth containing 3-HP to 3.5 to 5.5.

A fermentation broth containing 3-hydroxypropionic acid means one produced by a microorganism-based fermentation process, and generally contains 10% by weight or less of 3-HP in the fermentation broth.

The fermentation broth can be prepared by culturing a microorganism having the ability to produce 3-HP using glycerol as a carbon source. The microorganisms include Escherichia genus, Pseudomonas genus, Bacillus genus, Streptomyces genus, Serratia genus, Corynebacterium genus, Salmonella ( Salmonella genus, Clostridium genus, Lactobacillus genus, Klebsiella genus, or Saccharomyces genus microorganisms may be used. More preferably, Escherichia coli DH5a, E. coli JM109, E. coli K12, E. coli W3110, E. coli X1776, E coli B or E. coli XL1-Blue can be used. In particular, gram-negative bacteria of the Escherichia coli family including the W3110 strain genetically engineered to increase 3-HP production or to have resistance to a high-concentration 3-HP environment may be mentioned.

In addition, the pH of the fermentation broth may be adjusted to neutrality using an agent such as calcium hydroxide to prevent inhibition of the growth rate of microorganisms due to a decrease in pH as the concentration of 3-HP in the fermentation broth increases.

In addition, purification such as filtration may be performed to remove impurities present in the fermentation broth.

In the present invention, the pH of the fermentation broth is adjusted to a weak acid level of 3.5 to 5.5. Through this, 3-HP having a pKa of 4.51 can be partially reduced to a carboxylic acid form, and extraction of 3-HP in step 2 to be described later is made easier.

In addition, there is an advantage in that the unit cost of the material of the reactor (or extractor) can be lowered than that of a material that can withstand strong acid by treating with weak acid rather than strong acid as in the prior art.

In step 1, the pH adjustment may be performed by adding an acidic solution such as sulfuric acid or carbonic acid to the fermentation broth. In addition, it is preferable to stir for 1 hour to 3 hours after adding the acidic solution.

Meanwhile, step 1 may be performed at a temperature of 10 to 50°C, preferably at 20 to 30°C.

On the other hand, if the pH is adjusted by step 1, salts such as calcium ions contained in the fermentation broth ^may react to form a precipitate (Gypsum), and by filtering out these impurities, excessive calcium ions (Ca ²⁺ ) in the fermentation broth It can be removed and the recycling of the fermentation broth can be facilitated. Therefore, a step of removing these impurities may be additionally performed after pH adjustment.

(Step 2)

Step 2 is a step of preparing an extract containing 3-HP by adding an extraction solvent to the fermentation broth of step 1.

The extraction solvent used for the 3-HP extraction is not particularly limited as long as it is a 3-HP extraction solvent known in the art. Specifically, methyl ethyl ketone may be used as the extraction solvent.

When the extraction solvent is added to the fermentation broth of step 1, 3-HP contained in the fermentation broth of step 1 is dissolved in the extraction solvent, and phase separation occurs between the extraction solvent and the fermentation broth to separate and recover the extraction solvent. - An extract containing HP can be prepared.

Step 2 may be performed at a temperature of 10 to 50°C, preferably at 20 to 30°C. In addition, in step 2, it is preferable to perform phase separation in a separate separator after stirring to increase extraction efficiency, and the stirring may be performed by stirring at 100 to 500 rpm for 1 hour to 10 hours. At this time, since the pH condition of the fermentation broth is weak acid, extraction equipment requiring long-term stirring may not be exposed to strong acid.

The 3-HP extract recovered from the phase separation may be further subjected to steps such as purification and/or concentration to recover pure 3-HP. For example, a step of removing the solvent by heating the recovered 3-HP extract may be performed.

On the other hand, the filtrate remaining after extracting 3-HP in step 2 is recovered and subjected to the post-treatment process of step 3 to be described later, and then recycled as a culture medium of the fermentation broth containing 3-HP used in step 1. .

(Step 3)

Step 3 is a step of adjusting the pH of the filtrate of step 2 to 1 to 2 to lower the concentration of salts such as calcium ions in the filtrate.

In addition, the present invention may further include adding the product prepared in step 3 to the fermentation broth in step 1.

Since the filtrate prepared in step 2 contains unextracted 3-HP, it is economical to recycle it as a fermentation broth. In order to recycle the filtrate, an additional step is required to lower the concentration of salts such as calcium ions not removed by the Gypsum in the first acid treatment step, and therefore strong acid conditions are applied. In the conventional process, since the pH of the fermentation broth is lowered to strong acid in the first acid treatment step, a long mixing time is required and the cost of the reactor (extractor) of the extraction process exposed to strong acid increases. Strong acid conditions are also applied in step 3 of the present invention, but the amount and time to be treated are relatively short compared to the conventional process, so the unit cost of process equipment can be lowered.

In step 3, the pH adjustment may be performed by adding an acidic solution such as sulfuric acid or carbonic acid to the fermentation broth. In addition, it is preferable to stir for 1 hour to 3 hours after adding the acidic solution.

Meanwhile, step 3 may be performed at a temperature of 10 to 50°C, preferably at 20 to 30°C.

On the other hand, when the pH is adjusted by step 3, calcium ions contained in the extract may react to form a precipitate (Gypsum), which is an impurity, so a step of removing these impurities can be additionally performed after adjusting the pH. there is.

As described above, in the 3-HP production method according to the present invention, in extracting 3-hydroxypropionic acid from the culture medium, the effect of minimizing the equipment cost of the process exposed to the acidified fermentation broth due to the essential acid treatment there is.

1 shows a process chart according to an embodiment of the present invention.
2 shows a process chart of a comparative example.

Hereinafter, a preferred embodiment is presented to aid understanding of the present invention. However, the following examples are only provided to more easily understand the present invention, and the content of the present invention is not limited thereby.

Example

It was performed in the same process as in FIG. 1, and the area of each mixing tank is shown in Table 1 below.

First, in order to simulate the 3-HP fermentation broth, 1 t of 3-HP 10 wt% aqueous solution was prepared. The aqueous solution was put into a first mixing tank, and after adding 0.27 L of sulfuric acid, the mixture was stirred for 1.5 hours to adjust the pH to 4. After removing the precipitate (Gypsum) from the product with a filter for removing solid impurities, it was introduced into the second mixing tank.

1717 L of MEK (methyl ethyl ketone) as an extraction solvent was added to the second mixing tank and stirred for 4 hours. After the product was introduced into the separator, the 3-HP extract layer and the filtrate layer were separated through phase separation. The 3-HP extract layer was recovered, and the filtrate layer was introduced into a third mixing tank.

After adding 27.0 L of sulfuric acid to the third mixing tank, the mixture was stirred for 1.5 hours to adjust the pH to 2. After removing the precipitate (Gypsum) from the product with a filter for removing solid impurities, the filtrate was discharged.

comparative example

It was performed in the same process as in FIG. 2, and the area of each mixing tank is shown in Table 1 below.

As in Example, in order to simulate the 3-HP fermentation broth, 1 t of an aqueous solution of 10 wt% of 3-HP was prepared. The aqueous solution was put into a first mixing tank, and after adding 27.3 L of sulfuric acid, the mixture was stirred for 1.5 hours to adjust the pH to 2. After removing the precipitate (Gypsum) from the product with a filter for removing solid impurities, it was introduced into the second mixing tank.

1249 L of MEK (methyl ethyl ketone) as an extraction solvent was added to the second mixing tank and stirred for 4 hours. After the product was introduced into the separator, the 3-HP extract layer and the filtrate layer were separated through phase separation. The 3-HP extract layer was recovered, and the filtrate layer was drained.

Experimental example

In the above Examples and Comparative Examples, the acidic solution contact area of each mixing tank is summarized as shown in Table 1 below, and the 3-HP extraction yield is also shown.

Example comparative example 1st mixing tank A: first mixing tank area ^{1 )} 7.36 7.36 B: 7- (pH of acidic solution) 3 5 C: acidic solution contact time 1.5 hours 1.5 hours A×B×C 33.13 55.22 2nd mixing tank A: Second mixing tank area ^{1 )} 25.62 23.56 B: 7- (pH of acidic solution) 3 5 C: acidic solution contact time 4 hours 4 hours A×B×C 307.48 471.24 Third mixing tank A: Area of the third mixing tank ^{1 )} 7.36 - B: 7- (pH of acidic solution) 5 - C: acidic solution contact time 1.5 hours - A×B×C 55.22 - Total sum of A×B×C 395.84 526.46 3-HP recovery rate ^{2 )} 24% 33% 1) The total area of the bottom and side surfaces in contact with the acid solution in the mixing tank (m ² )
2) Value obtained by dividing the total amount of 3-HP recovered from the separator by the total amount of 3-HP injected into the first mixing tank

As described above, since the contact area and time with the acidic solution in the mixing tank in the example are significantly smaller than those of the comparative example, a relatively small amount of material that can withstand strong acid can be used, thereby reducing the unit cost of the production process. In particular, since a material that can withstand a strong acid at pH 2 must use a material that is about 2 to 5 times more expensive than a material that can withstand a weak acid at pH 4, the process according to the present invention can significantly lower the process unit cost.

Claims (10)

Adjusting the pH of the fermentation broth containing 3-hydroxypropionic acid to 3.5 to 5.5 (step 1);
recovering an extract containing 3-hydroxypropionic acid by adding an extraction solvent to the fermentation broth of step 1 and performing phase separation (step 2); and
Adjusting the pH of the filtrate of step 2 to 1.5 to 2.5 to remove residual impurities in the filtrate (step 3),
Method for producing 3-hydroxypropionic acid.
According to claim 1,
Step 1 is performed by adding an acidic solution of sulfuric acid or carbonic acid to the fermentation broth.
manufacturing method.
According to claim 2,
Stirring for 1 to 3 hours after the acidic solution is added,
manufacturing method.
According to claim 1,
Between the step 1 and step 2, further comprising the step of removing the precipitate from the product of step 1,
manufacturing method.
According to claim 1,
The extraction solvent in step 2 is methyl ethyl ketone,
manufacturing method.
According to claim 1,
Stirring for 1 hour to 10 hours after adding the extraction solvent in step 2,
manufacturing method.
According to claim 1,
The step 3 is performed by adding an acidic solution of sulfuric acid or carbonic acid to the extract of step 2,
Method for preparing 3-HP aqueous solution.
According to claim 7,
Stirring for 1 to 3 hours after the acidic solution is added,
manufacturing method.
According to claim 1,
Further comprising the step of removing the precipitate from the product of step 3,
manufacturing method.
According to claim 1,
Further comprising adding the product of step 3 to the fermentation broth of step 1,
manufacturing method.