JP2729285B2 - Purification method of sorbic acid - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for isolating sorbic acid from an aqueous solution containing sorbic acid obtained by microbiologically oxidizing sorbaldehyde.

[Prior art] Sorbic acid or a salt thereof has been used as a food preservative because of its excellent antifungal activity, but its industrial production method usually involves reacting crotonaldehyde with ketene. A method has been practiced in which the polyester is produced via an intermediately formed β-lactone, and then the polyester is thermally decomposed, acid-decomposed, or ion-exchange resin decomposed to form sorbic acid.

However, such a method is not always advantageous in terms of production and economy, for example, the recovery or purification operation of sorbic acid after polyester decomposition is troublesome, the process is long, and complicated process control is required.

As such a solution, a method for producing sorbic acid by treating sorbaldehyde with a specific microorganism has recently been proposed, and the present applicant has also filed a patent application.

[Problems to be Solved by the Invention] However, the reaction product solution containing sorbic acid produced by the oxidation method using microorganisms contains impurities such as a medium composition such as meat extract and peptone, and proteins and the like eluted by decomposition of microorganisms. It has been a challenge for industrialization to efficiently isolate sorbic acid from this reaction system, but there has been little report on a method for isolating sorbic acid from such a system. That is the fact.

The present inventors have examined membrane separation, crystallization, purification operations by distillation, but membrane separation is in terms of working life such as membrane clogging, crystallization is in terms of the purity of sorbic acid obtained, and In addition, it has been found that the distillation method has a drawback that it is necessary to esterify sorbic acid to a methyl ester or the like once, and it is difficult to employ any of these methods industrially.

Means for Solving the Problems However, the present inventors have converted the sorbic acid obtained by oxidizing sorbaldehyde with a microorganism into aliphatic hydrocarbons, aromatic hydrocarbons, halogen-containing hydrocarbons, ketones and ethers. When solvent extraction is performed using at least one kind,
The inventors have found that sorbic acid can be efficiently obtained, and have completed the present invention.

First, in the present invention, sorbaldehyde is oxidized by a microorganism, and any microorganism can be used as long as it has an oxidizing ability. Some examples include Mycobacterium rhodochrous, IF
O 13161), Rhodopseudomonas spheroid (Rhod
opseudomonas spheroides, IFO 12203), Streptomyces albidoflavas, (Streptomyces albidofl
avus, IFO 13010) Acetobacter ascendence (Ac
etobacter ascendens, IFO 3188), Acetobacter pasteurian subsp. rovanienen (Acet
obacter pasteurianus subsp.lovanien, IFO 1375
3) Alkagenes Eutrofus
eutrophus, ATCC 17699) and the like.

Of course, the present invention is not limited to these.

The oxidation reaction is carried out by any method such as adding sorbaldehyde to the medium in which the microorganisms are cultured, or collecting the microorganisms from the medium and adding the sorbaldehyde to a system in which the microorganisms are dispersed in water, saline, buffer, etc. I do.

Reaction temperature is 10-70 ° C, preferably 20-40 ° C, PH is 3-10
Preferably, the reaction time is selected from the range of about 4 to 9, and the reaction time is about 0.1 to 150 hours.

By carrying out such a reaction, an aqueous liquid containing sorbic acid is obtained, from which sorbic acid is isolated by solvent extraction.

As described above, the reaction is usually carried out at about PH 3 to 10,
Since sodium hydroxide, calcium hydroxide, potassium hydroxide, magnesium hydroxide and the like are used as a regulator, the sorbic acid produced is often present in the form of a salt in the system.

Therefore, after the reaction, it is necessary to first neutralize the sorbate with any acid such as hydrochloric acid, sulfuric acid, phosphoric acid and the like. Such operations are not necessarily required when sorbic acid is present in the free acid form. In any case, the pH of the system is 4 at the time of extraction.
It is necessary to control as follows.

The extraction operation can be performed by any method such as simple extraction, parallel-flow multistage extraction, and countercurrent multistage extraction, either in a batch system or a continuous system. Examples of the extraction apparatus include a mixer setra, a perforated plate extraction tower, an extraction tower with a stirrer (Mixco tower, Schibel tower, etc.), a spray tower, a packed tower, a centrifugal extraction apparatus (Podovirniak extraction apparatus, cyclone type extraction apparatus) and the like.

Examples of the extraction solvent include aliphatic hydrocarbons such as hexane, heptane, octane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, decalin, and mesitylene; halogen-containing hydrocarbons such as chlorobenzene and dichlorobenzene; and methyl isobutyl ketone. And ethers such as diethyl ether.

 A preferred solvent is toluene.

The temperature at the time of extraction and the amount of the extraction solvent used are not particularly limited and are arbitrary.

Since an organic solvent solution containing sorbic acid is obtained by such an operation, sorbic acid is isolated from the solution.
Usually, if the solvent is distilled off from the above solution, sorbic acid will crystallize, so it may be separated according to a conventional method. It is of course possible to add an azeotropic agent such as water when distilling off the solvent to carry out an efficient operation.

The obtained sorbic acid crystals can be sufficiently commercialized as they are, but known purification can be further carried out if necessary.

[Action] In the present invention, sorbic acid can be efficiently solvent-extracted from a sorbic acid-containing reaction solution obtained by microbial oxidation of sorbaldehyde.

EXAMPLES Next, the present invention will be described in more detail with reference to examples.

(Oxidation of Solved Aldehyde) Mycobacterium rhodochros (IF
O 13161) was added in an amount of 6 g on a dry basis, and the cells were sufficiently suspended by adding pH 7.0, 500 ml of 0.1 M phosphate buffer, and then 12 g of sorbaldehyde was added.
Was maintained at 6.8 to 7.1 (using potassium hydroxide for pH adjustment) to obtain an aqueous liquid (I) containing potassium sorbate. (This reaction was performed twice to produce a predetermined amount of a sorbic acid reaction solution.) The same reaction was performed in place of a microorganism to obtain the following sorbic acid-containing aqueous solution.

Example 1 1000 g of an aqueous liquid containing 32 g of potassium sorbate (PH6.
In 8), 25 ml of 36% acetic acid was added, the pH was adjusted to 2-3, and the mixture was heated to 75 ° C. At this temperature, this aqueous liquid was extracted with 220 g of toluene, and after separation, the toluene layer was separated. 15 water in toluene solution
0 g was added and the mixture was concentrated at 100 mmHg or less, and toluene was completely distilled off to obtain an aqueous suspension of sorbic acid.

The sorbic acid crystals were separated from the suspension and dried.
23.9 g of sorbic acid (97% recovery) were obtained.

Examples 2 to 15 Experiments were carried out according to Example 1 using various extraction solvents. The results are shown in the table.

[Effect] In the present invention, sorbic acid can be efficiently isolated from the sorbic acid-containing aqueous solution by extracting with a specific solvent.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication (C12P 7/40 C12R 1:01) (C12P 7/40 C12R 1: 465) (C12P 7/40 (C12R 1:02) (C12P 7/40 C12R 1:05)

Claims (1)

(57) [Claims] A sorbic acid-containing aqueous solution obtained by oxidizing sorbaldehyde with a microorganism to convert the sorbic acid into at least one of aliphatic hydrocarbons, aromatic hydrocarbons, halogen-containing hydrocarbons, ketones and ethers. A method for purifying sorbic acid, comprising extracting a solvent with a solvent.