KR820001432B1 - Method of recoverin glutamic acid - Google Patents

Abstract

A highly purified L-glutamine is recovered from the molasses fermentation by a low-priced refining system. This recovery method is industrially & economically stabilized. 1) L-glutamine is fermented with molasses removed calcium. The supernatants of glutamine, being recovered from molasses fermenting mother liquor processes, is neutralized with crude sulfate. 2) The conc. and crystn. of the sepq. liquor on the isoelectric point (pH 3.2) of glutamine resulted in the sepn. of crude crystal glutamine. 3) Crude cryst. glutamine redissolved in sulfate soln. (3-8N) is sepd. insol. mixts. (plaster, microbes) and used in a cyclic neutralization with sulfate.

Description

Recovery method of glutamic acid

The present invention relates to a method for industrially and economically and stably recovering high-purity L-glutamic acid from a glutamic acid fermentation broth based on sugars by an inexpensive purification facility.

In the conventional method, waste molasses is mainly used as a raw material of glutamic acid. The glutamic acid fermentation broth containing molasses contains minerals such as potassium and calcium in addition to cells, sugars, pigments, and other amino acids, and the calcium component is glutamic acid recovery. When sulfuric acid is used in the process, insoluble calcium sulfate (gypsum) is produced, which impedes crystallization or is incorporated into the product.

However, the present invention is a method for recovering glutamic acid for a glutamic acid fermentation broth having a calcium concentration of 0.7 g / l or less by adding sulfuric acid to molasses and adjusting the pH to 2-4 by a known method.

If this method is described by process, it goes through three steps as follows.

[First Process]

The glutamic acid fermentation broth can be neutralized directly with cheap sulfuric acid to separate high purity glutamic acid without coprecipitation of gypsum crystals. .

In the conventional method of directly recovering glutamic acid fermentation broth, it is difficult to use sulfuric acid during neutralization due to the concentration of impurities such as calcium, and the purified glutamic acid has low purity.

Comparing the purity of the glutamic acid recovered in the present invention and the conventional direct concentration method and crystallization yield is as follows.

Second Process

It is a mother liquor treatment process of glutamic acid which can directly collect glutamic acid crystals by adding an additive to a mother liquor separated at an isoelectric point and concentrating as it is in a state containing microbial cells.

In the conventional mother liquor treatment method, the mother liquor may be discarded or some mother liquor may be concentrated and added and decomposed into glutamic acid filtrate by adding and decomposing. In addition to the need for expensive acid-resistant equipment, the separation of glutamic acid in solution resulted in the solubility of impurities and the impurity concentration of the main process.

The present inventors put 0.1-0.5 g / l of sodium hexametaphosphate (hereinafter referred to as HMP), which is generally used as a water softener, to concentrate glutamic acid mother liquor to inhibit the action of glutamic acid crystallization ions such as calcium and glutamic acid. It has been found that the solubility can be increased to prevent the generation of scale in the heat exchanger of the condenser tube.

In this way, the concentration of glutamic acid at the isoelectric point pH (near 3.2) does not require expensive acid-resistant facilities made of titanium (Ti), palladium (Pd), etc. This strong chlorine ion concentration is insignificant, and the commonly used stainless steel is sufficient, so it is economical.

Concentration is reduced to 1 / 2-1 / 4 under vacuum, and when cooled and crystallized, glutamic acid can be separated again from the mother liquor mixed with impurities.

[Third process]

In the recovered glutamic acid crystals, poorly soluble impurities such as microorganisms and gypsum crystals may be mixed, but by adding 4 liters of sulfuric acid solution prepared in 3-8N per kg glutamic acid to dissolve glutamic acid, the glutamic acid can be easily separated from the gastric impurities. .

This filtrate can improve the formulation rate of glutamic acid by increasing the purity and concentration of glutamic acid while recovering the active sulfuric acid component by circulating the fermentation broth.

Briefly, the present invention is as follows.

The characteristics of the present invention as above

First, glutamic acid fermentation broth obtained by removing calcium from molasses in advance can be directly neutralized by using glutamic acid filtrate recovered in the mother liquor processing process and inexpensive sulfuric acid to improve the purity and recovery rate of glutamic acid.

Second, by adding HMP to the separation mother liquor and concentrating as it is under isoelectric point pH, it is possible to prevent the formation of scale in the pipe and to directly determine and separate glutamic acid even in the presence of impurities.

Third, the glutamic acid crystals recovered from the mother liquor can be dissolved in sulfuric acid solution and separated from poorly soluble impurities.

Next, the method of the present invention will be described in more detail with reference to Examples.

However, this invention is not limited to these Examples.

Example 1

3000 ml of glutamic acid fermentation broth (glutamic acid concentration 75g / l, calcium concentration 0.5g / l) was gradually neutralized with 250l of strong acidic glutamic acid filtrate (170g / l glutamic acid concentration) and 35l of 98% sulfuric acid and adjusted to pH3.2. Cooling crystallization afforded 278 kg of crude glutamic acid crystals having a purity of 97% and a content of 72%.

Then, HMP470g was added to 2990 l of the separated mother liquor (glutamic acid concentration 22.3 g / l), concentrated to 1/3 under vacuum reduction, and then cooled and crystallized again. 81 kg of 50% crude glutamic acid crystals were separated, and 5N sulfuric acid solution was added thereto. After dissolving to 200 L and filtering, 240 L of glutamic acid filtrate with a purity of 90.5% (glutamic acid concentration of 165 g / l) was obtained and used for the next neutralization of glutamic acid fermentation.

As a result, the recovery rate of the joglutamic acid crystal was 87.7%.

Example 2

2,280 g of glutamic acid fermentation broth (glutamic acid 78 g / l, Ca concentration 0.6 g / l) was adjusted to pH 3.2 with the total amount of the filtrate obtained in Example 1 and industrial concentrated sulfuric acid, and cooled and crystallized to 272 kg of crude glutamic acid crystals having a purity of 97.5% and 71.4% Got it.

Subsequently, HMP850g was added to 2830 L of separated mother liquor (glutamic acid concentration (22.6 g / l)), concentrated to 1010 L in a vacuum of 700 mmHg, and again cooled and crystallized to obtain 77.4 kg of joglutamic acid having a content of 48%, and reused with sulfuric acid solution prepared at 6N. Then, 250 liters of glutamic acid filtrate with a purity of 92% (glutamic acid concentration of 148 g / l) was filtered off and circulated for neutralization of the next glutamic acid fermentation broth.

Claims (1)

As described above, the glutamic acid filtrate recovered in the mother liquor treatment step was neutralized with sulfuric acid to purify the glutamic acid fermentation broth having a calcium concentration of 0.7 g / l or less, which had been fermented by removing calcium in molasses in advance. After the separation of tamic acid, the mother liquor was concentrated 1 / 2-3 / 4 at the isoelectric point pH of the glutamic acid and crystallized to separate the crude glutamic acid crystals, which were re-dissolved in 3-8N sulfuric acid solution to obtain gypsum and A method for recovering glutamic acid, characterized by filtering poorly soluble impurities such as cells and circulating the filtrate for neutralization of glutamic acid fermentation broth.