JPS5886090A - Separation of dicarboxylic acid - Google Patents

Abstract

PURPOSE:To recover a dicarboxylic acid, economically, in high efficiency, from a fermentation liquid containing the dicarboxylic acid as a salt, by removing the microbial cells from the liquid, treating the liquid with a strong acid, and extracting the objective compound with an alicyclic alcohol and/or an aromatic alcohol. CONSTITUTION:Microbial cells are removed from the fermentation liquid containing a dicarboxylic acid as a salt and obtained by conventional process, and the pH of the residual fermentation liquid is adjusted to <=4.0, preferably <= 3.0 with a strong acid such as sulfuric acid, hydrochloric acid, etc. to precipitate the free dicarboxylic acid. The dicarboxylic acid is extracted with an alicyclic alcohol and/or an aromatic alcohol such as cyclohexanol, benzyl alcohol, etc. The amount of the extractant should be sufficiently large to form two layers with the fermentation liquid. If necessary, the extracted liquid is brought into contact with an aqueous solution of an alkali to extract the dicarboxylic acid with the solution, and the dicarboxylic acid is precipitated by treating the extract with a strong acid.

Description

[Detailed description of the invention] The present invention relates to a method for purifying dicarboxylic acids.

More specifically, the present invention relates to a method for purifying dicarboxylic acids produced by fermentation.

In recent years, attempts have been made to produce dicarboxylic acids by microbial fermentation using n-paraffin as a raw material. In general, in order to separate and purify dicarboxylic acids produced by fermentation methods from fermentation liquor, there are two methods: (1) removing bacterial cells from fermentation liquor and then precipitating them as insoluble metal salts such as calcium salts;
) A method of distilling off the solvent after extraction with ether, (6)
Known methods include adding an alkali metal salt and a soluble inorganic metal salt to cause salting out as a dialkali metal salt, and (4) adding acid f to cause acid precipitation. Among these methods, the acid precipitation method is considered to be advantageous because the treatment process is simple, but in reality, acid precipitation may occur due to the influence of n-' paraffin, which is a fermentation raw material, or proteins in the fermentation liquid. The crystals precipitated by the analysis become scaly and microcrystalline, resulting in extremely poor water removal efficiency during P over-separation, which poses a problem in terms of industrialization. After acid precipitation, crystal growth can be promoted by heating, but generally the dicarboxylic acid concentration in the fermentation liquid is, for example, 3 to 6.
%, heating such a fermentation liquid requires a large amount of energy and is not economical.

There is also a method of dissolving and extracting the acid-precipitated dicarboxylic acid in aromatic hydrocarbons to separate it from the fermentation liquid, but since the solubility of aromatic hydrocarbons at around room temperature is not high enough, it is necessary to heat the dicarboxylic acid to temperatures above 75°C. Otherwise, there is a drawback that extraction cannot be performed efficiently.

The present inventors discovered that the above-mentioned high-temperature heating operation is not necessary;
As a result of investigating a simpler method for isolating dicarboxylic acids from fermentation broth, the following method was discovered. That is, the present invention provides a method for producing dicarboxylic acid by fermentation, in which dicarboxylic acid is separated and obtained from a fermentation broth containing dicarboxylic acid as a salt by applying a strong acid to the fermentation broth from which bacterial cells have been separated in advance. is released, the liberated dicarboxylic acid is extracted into a sufficient amount of alicyclic alcohol and/or aromatic alcohol to form two layers with the fermentation liquid, and the extracted alicyclic alcohol and/or aromatic alcohol is This is a dicarboxylic acid separation method characterized by recovering dicarboxylic acid from a layer.

The present invention is a method for producing dicarboxylic acid r11 by a fermentation method, in which a fermentation liquid containing dicarboxylic acid as a salt is used as a raw material. Means for obtaining such a fermentation liquid are already known. In other words, it is aerobic fermentation using various secondary element sources and microorganisms that can produce dicarboxylic acids, but dicarboxylic acids are produced by basic compounds added for the purpose of adjusting P and H during fermentation. Obtained as salt.

Examples of the dicarboxylic acids include speric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid,
．． 10-decanedicarboxylic acid, brassylic acid, 1.12-
Examples include dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, tabsic acid, and the like. Among these, it is particularly effective for aliphatic dicarboxylic acids having 10 or more carbon atoms.

The raw material for producing the above dicarboxylic acid by microbial fermentation is preferably n-paraffin or a hydrocarbon containing it, particularly preferably n-paraffin having the same number of carbon atoms as the target dicarboxylic acid. - Paraffin is a good choice.

Examples of microorganisms that can produce dicarboxylic acid from n-paraffin include yeast belonging to the genus Torulopsis, which has the ability to produce dicarboxylic acid, as described in JP-A No. 49-25186, or yeast belonging to the genus Candida. The yeasts belonging to this species are known.

The process of the method of the present invention will be explained in detail. In the present invention, first, microbial cells are removed from the fermentation liquid.

Dicarboxylic acids are dissolved as alkali metal salts in the fermentation liquid due to alkali metal hydroxides added to adjust the pH during fermentation, so bacterial cells can be separated by filtering or centrifuging the fermentation liquid. can do.

Next, in the present invention, a strong acid, such as an inorganic acid, is applied to the fermentation liquid from which the bacterial cells have been separated, preferably to a pH of about 4.0 or below, to precipitate free dicarboxylic acids.An inorganic acid that can be used for this acid precipitation Examples include sulfuric acid, hydrochloric acid, and nitric acid. These inorganic acids are usually used as an aqueous solution. The pH during acid precipitation is at least 4.0 or less,
The pH value is preferably 6.0 or less, and the smaller the pH, the higher the yield of dicarboxylic acid.

The fermented liquor in which the dicarboxylic acid has been precipitated is brought into contact with enough alicyclic alcohol and/or aromatic alcohol to form two layers with the fermented liquor, and the dicarboxylic acid is extracted into the alcohol layer. Of course, a method may be adopted in which the alcohol is brought into contact with the fermentation liquid before acid precipitation, and extraction is performed while acid precipitation is performed. Examples of alcohols that can be used for this purpose include alicyclic alcohols such as Lopentanol and cyclohexanol, and aromatic alcohols such as benzyl alcohol and methylbenzyl alcohol. The amount of alcohol used for extraction is sufficient to form two layers with the fermentation liquid, and it is preferable not to use too much alcohol, usually 6 to 4 parts by volume per 10 parts by volume of the fermentation liquid. It is preferable to set it as approximately. The alcohol may also be used in combination with other water-insoluble solvents, such as hydrocarbons.

The extraction operation can be carried out batchwise or continuously, such as parallel flow,
This can be done by a method such as a countercurrent method.

The alcohol layer from which the dicarboxylic acid has been extracted is separated from the aqueous layer by, for example, standing still, and then used to recover the dicarboxylic acid. In recovering the dicarboxylic acid, the dicarboxylic acid may be simply crystallized by concentration (11) and cooling, or the dicarboxylic acid may be brought into contact with a small amount of aqueous alkali solution, and the dicarboxylic acid is extracted as an alkali salt into the aqueous alkali layer. The alkali-aqueous solution layer may be separated and further brought into contact with a strong acid to crystallize dicarboxylic acid crystals. In the latter method, it is sufficient to use the alkaline aqueous solution in a volume of about 1/3 to 1/2 of the alcohol;
A solution of the dicarboxylic acid salt with a higher concentration than that in the original fermentation liquid can be obtained, and the amount of liquid to be handled can be reduced, which is advantageous in terms of equipment and equipment usage.

Next, a concrete explanation will be given with reference to examples.

Example 1 n-) Bacterial cells were removed from a culture containing brassylic acid produced by culturing Torulopsis candida using Rhizocane as a raw material. Next, 500 ml of this supernatant liquid (brassyl acid
．． (containing 5 g) was placed in a No. 11 flask with a bottom outlet, and an aqueous hydrochloric acid solution was added to adjust the pH to 3.5 to precipitate brassylic acid. Next, 1 som/dichlorohexanol was added and heated to 50° C., stirred and left to stand, and among the two separated phases, the aqueous phase was removed.

The cyclohexanol phase was concentrated under reduced pressure, and the
After wetting out rJ cyclohexanol, it was cooled to precipitate brassylic acid. The mixture was filtered with suction and dried to obtain 9.3 g of brassylic acid crystals.

Example 2 Using the same apparatus as in Example 1, a culture solution of 5 oort+# (containing 10.5 g of brassylic acid 7) was acid-precipitated in the same manner, and
Add 0 m# of cyclohexanol and stir to extract.

After removing the aqueous phase, 5N hydroxide) IJum solution IClO
mI! was added and stirred to dissolve the heprasylic acid in the aqueous phase of sodium hydroxide. Next, the pH was adjusted to 3 with hydrochloric acid, and brassylic acid was precipitated and recovered to obtain 9.1 g of brassylic acid.

Example 3 Using the same apparatus as in Example 1, 500 m+7/(containing 19 g of brassylic acid) of the culture solution was acid-precipitated in the same manner, and 400 m7?
The mixture was heated to 0°C and stirred to extract brassylic acid into the benzyl alcohol layer. The benzyl alcohol layer was separated, cooled to 5°C, and after filtration, n-
Washing with hexane and drying yielded 14 g of brassylic acid.

The protein content in this brassylic acid was 500 ppm.

Brassylic acid obtained by acid precipitation of the same culture solution has 3,0
It contained 00 ppm of protein. Therefore, it has become clear that Kenpo has a remarkable effect on removing protein from brassylic acid.

Example 4 The same apparatus as in Example 1 was used, except that a culture containing 23 g/ff of sebacic acid was used instead of brassylic acid, and the same operation was performed to prepare a culture solution containing 11.5 g of sebacic acid. 3 g of sebacic acid per skin was separated and recovered from 5'00me.

Applicant: Mitsui Petrochemical Industries, Ltd. Agent Kazu Yamaguchi

Claims (1)

[Claims] (Li) In a method for producing dicarboxylic acid by a fermentation method, in order to separate and obtain dicarboxylic acid from a fermentation liquid containing dicarboxylic acid as a salt, a strong acid is applied to the fermentation liquid from which bacterial cells have been separated in advance. An alicyclic alcohol and/or aromatic in an amount sufficient to liberate a dicarboxylic acid and form a two-layered layer with the liberated dicarboxylic acid with the fermentation liquid. A method for separating dicarboxylic acid characterized by recovering dicarboxylic acid from an alcohol and/or aromatic alcohol layer. (2) When recovering dicarboxylic acid from an alicyclic alcohol and/or aromatic alcohol layer, alicyclic alcohol and Alternatively, the dicarboxylic acid is extracted into the alkaline aqueous solution by contacting the aromatic alcohol solution and the alkaline aqueous solution,
The method according to claim (1), characterized in that the extract is then treated with a strong acid to precipitate the dicarboxylic acid.