JPH10287603A - Purification of erythritol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To purify erythritol economically and easily by hydrolyzing a fermented liquid containing erythritol after removing microbial cells with an acid, and crystallizing it. SOLUTION: This method for purifying erythritol is constituted by fermenting glucose with erythritol producing microorganisms such as Monilliella tomentosa var. polinis, Candida polymorpha, Trigonopsis variabilis and Aureobasidium, separating microbial cells by a centrifugal separation, etc., to obtain a fermented liquid containing erythritol, hydrolyzing the separated fermented liquid containing erythritol with an acid, preferably after concentrating the liquid, by preferably using a strongly basic acid [0.1-1.0 wt.% acid concentration] usually at 100-145 deg.C for 10 min to 1 hr, then concentrating the liquid up to 50-80 wt.%, precipitating erythritol crystals by adding a small amount of seeds as necessary, recovering the crystals by the centrifugal separator, etc., performing a usual purification treatment, and then concentrating and crystallizing to obtain the objective compound of a high purity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention relates to a method for purifying erythritol.

[0003]

2. Description of the Related Art

[0004] Erythritol is a sugar alcohol of tetracarbon sugar contained in lichens, mushrooms, and fruits (pears, grapes, watermelons, melons, etc.).

Erythritol generates little energy in the body and is a sweetener having a sweetness of about 75% of sugar. It is non-cariogenic, has a great cooling sensation, has low hygroscopicity, and has a good taste.・ It has many excellent properties, such as high odor-correcting effect and small laxative effect, so it is used not only for many foods such as drinks and candy, but also for cosmetics and pharmaceuticals. I have.

[0006] Erythritol is usually produced by fermenting glucose with yeast. Specific production methods include erythritol such as Moniliella Tomentosa Var. Pollinis, Candida Polymorpha, Trigonopsis Variabilis, and Aureobasidium. A method using a producing bacterium is disclosed in Applied Microbiology, Vol. 12, No. 3, 240
-246 (1964), JP-B-37-3546, JP-B-4-11189, JP-B-6-3059.
It is introduced in many publications such as Japanese Patent Publication No. 3 and patent publications.

The erythritol-containing fermented broth obtained by fermenting glucose using these erythritol-producing bacteria is usually obtained by removing the cells from the erythritol-containing fermentation solution by centrifugation or the like, and then removing the coloring substances and the like using activated carbon. Erythritol crystals are produced by performing a purification treatment with an ion exchange resin, concentrating and crystallizing.

However, in general, in a production method by fermentation,
In addition to producing glycerol and ribitol besides erythritol, yeast sources, nitrogen sources such as urea, and inorganic salts such as magnesium sulfate and disodium phosphate are added in addition to erythritol-producing cells. The load of purification of the fermentation liquid is extremely large, a large amount of ion exchange resin is required for purification, and the amount of wastewater treatment generated by regeneration of the used ion exchange resin is enormous.

[0009] Furthermore, turbidity occurs in the concentrated liquid which has been subjected to ordinary activated carbon treatment or ion exchange resin purification treatment, and when the erythritol crystals separated from the concentrated liquid are dissolved again in water, the turbidity is generated again. It is already known that this turbidity is a polysaccharide mainly composed of glucose produced in the fermentation step, and is not removed only by activated carbon treatment or passing through a column filled with an ion exchange resin. Polysaccharides make the erythritol crystals precipitated in the crystallization process finer, so that it is difficult to separate the crystals from the crystal mother liquor.

As a method for removing this polysaccharide, a culture solution containing erythritol obtained by culturing an erythritol-producing bacterium has a molecular weight cut off of 1,000 to 100,000.
Erythritol is recovered by filtration through an ultrafiltration membrane (Japanese Patent Publication No. 7-34750), and the culture solution is passed through a separation column filled with a strongly acidic cation exchange resin of alkali metal or ammonium type. For recovering erythritol by collecting the fractions described in JP-B-7-34748 and JP-A-1-32098.
No. 7) has been reported.

[0011] However, the ultrafiltration membrane not only requires an expensive apparatus but also requires periodic cleaning of the membrane surface, which makes the management complicated, and a separation tower packed with a strongly acidic cation exchange resin. However, there remain problems such as the fact that the concentration of the processing solution becomes low, the cost of concentration in the subsequent step becomes high, and the recovery rate of erythritol decreases.

An object of the present invention is to solve the above-mentioned problems and to provide a method for economically and easily purifying an erythritol-containing fermentation solution.

[0013]

[Means for Solving the Problems]

The present inventors have conducted intensive studies in order to solve the above-mentioned problems. As a result, the polysaccharide contained in the fermentation broth was easily hydrolyzed with an acid, and erythritol was compared with the polyol contained in the fermentation broth. Focusing on the fact that it is easy to precipitate as crystalline crystals, we found that impurities, including polysaccharides, contained in the fermentation broth can be easily removed by acid hydrolysis and crystallization of the fermentation broth after removing the cells. The invention has been completed.

That is, means for solving the problems of the present invention are as follows.

First, a method for purifying erythritol in which the erythritol-containing fermented solution from which the cells have been removed is acid-hydrolyzed, and erythritol crystals are recovered by crystallization. Second, a method for purifying erythritol in which erythritol crystals are recovered by crystallization from the erythritol-containing fermented solution after removing the cells, and the obtained erythritol crystals are dissolved in water to acid-hydrolyze. Third, in the acid hydrolysis, any one of sulfuric acid, hydrochloric acid and phosphoric acid is used, and the acid concentration in the acid hydrolysis solution is 0.1% by weight to 1.0% by weight. The method for purifying erythritol according to the first or second aspect, wherein the method is carried out at a temperature of 100 to 145 ° C.

In the purification of the present invention, glucose is fermented using commonly used erythritol-producing cells such as Moniliella tomentosa var polynis, Candida polymorpha, Trigonopsis variabilis, Aureobasidium and the like. An erythritol-containing fermentation broth obtained by separating cells by centrifugation or the like is used.

In the present invention, the erythritol-containing fermented liquid from which the erythritol-producing bacteria have been removed is acid-hydrolyzed as it is or after being concentrated. It is preferable because the amount of acid required for acid hydrolysis can be reduced.

For the acid hydrolysis of the present invention, any acid may be used as long as it is a strong basic acid, and among them, any one acid selected from sulfuric acid, hydrochloric acid and phosphoric acid is used. It is preferable because of easy handling and low cost.

The acid concentration in the acid hydrolysis of the present invention is such that the acid concentration in the acid hydrolysis solution is in the range of 0.1% by weight to 1.0% by weight.

When the acid concentration in the acid hydrolysis solution is lower than 0.1% by weight, the acid hydrolysis of the polysaccharide contained in the fermentation solution is not sufficiently performed, and the resulting erythritol crystals are dissolved in water. It cannot prevent cloudiness.

When the acid concentration in the acid hydrolyzate is higher than 1.0% by weight, the salt concentration in the fermentation solution is high, so that the purification load in the subsequent purification step is increased, and the recovery of erythritol is further increased. The rate is also undesirably reduced.

The acid hydrolysis of the present invention is usually carried out at a temperature in the range of 100 to 145 ° C.

When the temperature is lower than 100 ° C., the acid hydrolysis does not proceed sufficiently, and when the temperature is higher than 145 ° C., the produced erythritol may be decomposed.
Not preferred.

Although the treatment time of the acid hydrolysis of the present invention varies depending on the kind, concentration and temperature of the acid employed, it is usually 10 hours.
The object of the present invention can be achieved by treating for 1 minute to 1 hour. The acid-hydrolyzed fermentation solution containing erythritol is neutralized with a base such as sodium hydroxide or potassium hydroxide as necessary.

The acid-hydrolyzed fermentation solution containing erythritol is concentrated to a concentration of 50% by weight to 80% by weight, and erythritol crystals are easily precipitated by adding a small amount of seeds as necessary.

The precipitated erythritol crystals are recovered by a centrifugal separator or the like, redissolved in water, subjected to a purification treatment using activated carbon or an ion exchange resin, which is usually performed, and then concentrated and crystallized again. Erythritol crystals with high purity can be obtained.

Further, in the present invention, acid hydrolysis can be carried out on erythritol crystals obtained by concentrating and crystallizing an erythritol-containing fermentation solution from which erythritol-producing bacteria have been removed.

By practicing the present invention, the capacity of ion exchange equipment and wastewater treatment equipment normally required in the step of purifying an erythritol-containing fermentation solution can be greatly reduced, and the production cost of erythritol also decreases.

[0030]

【Example】

Hereinafter, the method of the present invention will be described more specifically with reference to examples, but the technical scope of the present invention is not limited to the following examples. In the following examples, g / L represents the number of grams per liter, and%
Represents% by weight unless otherwise specified. Furthermore,
Erythritol purity was analyzed using high performance liquid chromatography.

[0032]

Embodiment 1

[Preparation of fermentation liquid] Anhydrous crystalline glucose 112
A medium containing g / L and corn stapler 11.2 g / L was inoculated with Moniliella tomentosa var polynis (CBS 461.67) and shake-cultured at 30 ° C. for 4 days to obtain a pre-culture solution. . Next, 3 kg of anhydrous crystalline glucose, 225 g of corn staple liquor, 800 ml of the pre-culture liquid and water were added to a 30 liter jar fermenter to make the total amount 15 liters, and the air volume 1
The cells were cultured for 12 days at 5 liter / min, a stirring speed of 500 rpm and a temperature of 30 ° C. Next, cells were separated from the culture solution by centrifugation, 5 g of activated carbon was added to the obtained separated solution, and the mixture was heated at 50 ° C. for 1 hour, and then the activated carbon was removed by filtration. The obtained erythritol-containing fermentation broth contained 73.0 g / L of erythritol, 5.0 g / L of glycerin, and 7.1 g / L of other substances (including organic acid salts).

[Hydrolysis] To 10 liters of the obtained erythritol-containing fermentation broth, 50 g of sulfuric acid was added.
After heating for 0 minutes, cool and add 20% aqueous sodium hydroxide
Neutralized to H6.

[Crystallization] The above neutralized solution was concentrated to a concentration of 66%, placed in a 2 liter crystal can, cooled from 60 ° C. to 40 ° C. over 8 hours, and erythritol crystallized at 57 ° C. By adding 1 g as a seed, a slurry containing erythritol crystals was obtained. Crystals were separated from the slurry using a centrifugal separator, and the crystals were washed with a small amount of water to obtain 378 g of erythritol crystals (one crystal) and one crystal mother liquor. The obtained erythritol crystal (single crystal) had a water content of 2.3% and an erythritol purity of 98.8%. The erythritol purity of the mother liquor is 65.6%.
Met. Further, the mother liquor is concentrated to a concentration of 70%,
After cooling from 0 ° C to 30 ° C over 12 hours, 55
A slurry containing erythritol crystals was obtained by adding 1 g of erythritol crystals as a seed at ° C. The slurry was separated from the crystals using a centrifugal separator, and the crystals were washed with a small amount of water to obtain erythritol crystals (two crystals).
8.1 g and 2 crystal mother liquors were obtained. Erythritol crystals (2
Crystal) has a water content of 3.2% and an erythritol purity of 97.2.
%Met. The erythritol purity of the mother liquor was 4
It was 9.4%.

[Purification and crystallization] One and two crystals of the obtained erythritol crystals were dissolved in water to a concentration of 30%.
Add 3 g of activated carbon ("Shirasagi" manufactured by Takeda Pharmaceutical Co., Ltd.)
After stirring at 50 ° C. for 1 hour, the activated carbon was separated by filtration.
The filtrate was passed through 100 ml of a cation exchange resin IRB-120 (manufactured by Organo Co., Ltd.) and 100 ml of an anion exchange resin IRA-410 (manufactured by Organo Co., Ltd.), concentrated to a concentration of 65%, and concentrated in 1 liter. Transfer to a crystallizer with a stirrer,
After cooling to 0 ° C., a slurry containing erythritol crystals was obtained. During this time, 1 g of erythritol crystals was added at 60 ° C. as a seed. The slurry was separated into erythritol crystals and a mother liquor by a centrifugal separator. The erythritol crystals were washed with a small amount of water, and then dried at 60 ° C. under reduced pressure to obtain 325 g of erythritol crystals. The purity of the erythritol crystals is 99.9%, a part of which is dissolved in water,
When an aqueous solution having a concentration of 30% was prepared, the aqueous solution was colorless and transparent, and no cloudiness was observed.

[0037]

Embodiment 2

An erythritol-containing fermentation broth from which cells were removed was prepared in the same manner as in Example 1.

[Crystallization] 10 liters of the obtained erythritol-containing fermentation broth was concentrated to a concentration of 63%, then transferred to a 2 liter crystal can, and heated to 35 ° C. from 60 ° C. for 8 hours.
Then, a slurry containing erythritol crystals was obtained. During this time, 1 g of erythritol crystals was added as a seed at 57 ° C. Crystals were separated from the slurry using a centrifugal separator, and the crystals were washed with a small amount of water to obtain 430 g of erythritol crystals (one crystal) and one mother liquor. The obtained erythritol crystal (single crystal) had a water content of 2.3% and an erythritol purity of 99.0%. The erythritol purity of the single crystal mother liquor was 73.0%. Further, the single crystal mother liquor was concentrated to a concentration of 68%, cooled from 60 ° C. to 20 ° C. over 16 hours, and 1 g of erythritol crystals were added as seeds at 55 ° C. to obtain a slurry containing erythritol crystals. . Crystals were separated from the slurry using a centrifuge, and the crystals were washed with a small amount of water to obtain 181 g of erythritol crystals (two crystals) and a two-crystal mother liquor. The obtained erythritol crystals (two crystals) have a water content of 3.2%,
Erythritol purity was 98.0%. The erythritol purity of the mother crystal liquor was 55.6%. Subsequently, the mother crystal liquor was concentrated to a concentration of 73%,
After cooling to 10 ° C. over 8 hours, 1 g of erythritol crystals were added as seeds at 55 ° C. to obtain a slurry containing erythritol crystals. Crystals were separated from the slurry using a centrifugal separator, and the crystals were washed with a small amount of water to obtain 84 g of erythritol crystals (three crystals) and a three-crystal mother liquor. The obtained erythritol crystals (three crystals) had a water content of 3.8% and an erythritol purity of 91.0%.
The erythritol purity of the mother liquor was 38.7%. One, two and three erythritol crystals were dissolved in water to a concentration of 40%. At this time, the erythritol purity was 97.8%.

[Hydrolysis] To a 40% aqueous solution of erythritol was added 3.3 g of sulfuric acid, heated at 140 ° C. for 20 minutes, and neutralized to pH 6 with a 20% aqueous sodium hydroxide solution. Next, 5 g of activated carbon was added, and after heating at 50 ° C. for 1 hour, the activated carbon was removed by filtration. In addition, 100 ml of cation exchange resins IRB-120 and 200
The solution was passed through a milliliter anion exchange resin IRA-410, concentrated to a concentration of 65%, and erythritol was crystallized in the same manner as in Example 1 to obtain 399 g of erythritol crystals. A part of the obtained erythritol crystals was dissolved in water, but it was colorless and transparent, and no cloudiness was observed.

[0041]

Embodiment 3

An erythritol-containing fermentation broth from which cells were removed was prepared in the same manner as in Example 1.

[Hydrolysis] 10 liters of the obtained erythritol-containing fermentation broth was concentrated to a concentration of 40%, 30 g of 35% hydrochloric acid was added, the mixture was heated at 130 ° C. for 30 minutes, cooled, and cooled to 20%.
Neutralized to pH 6 with aqueous sodium hydroxide.

[Crystallization] Next, the hydrolyzed solution was concentrated to a concentration of 6.
Concentrate to 7% and place in a 2 liter crystal can at a temperature of 6
Cooled from 0 ° C to 30 ° C over 8 hours, and 57 ° C on the way
Then, a slurry containing erythritol crystals was obtained by adding 1 g of erythritol crystals as a seed. The slurry was subjected to crystal separation using a centrifugal separator, and the crystals were washed with a small amount of water to obtain erythritol crystal (single crystal) (416 g).
And 1 crystal mother liquor was obtained. The obtained erythritol crystals (1
Crystal) has a water content of 2.4% and an erythritol purity of 98.9.
%Met. The erythritol purity of the single crystal mother liquor is 7
1.1%. Further, the 1-crystal mother liquor was concentrated to a concentration of 71%, cooled from 60 ° C. to 30 ° C. over 12 hours, and 1 g of erythritol crystals were added at 55 ° C. as a seed to obtain a slurry containing erythritol crystals. . The slurry was separated from the crystals using a centrifuge, and the crystals were washed with a small amount of water.
180 g) and two crystal mother liquors were obtained. Erythritol crystals (two crystals) have a water content of 3.4% and an erythritol purity of 9%.
7.5%. The erythritol purity of the mother crystal liquor was 55.0%.

[Purification and crystallization] One and two crystals of the obtained erythritol crystals were dissolved in water to a concentration of 30%.
In the same manner as in Example 1, 3 g of activated carbon was added, and the mixture was stirred at 50 ° C. for 1 hour, and then the activated carbon was separated by filtration. The filtered liquid is
Continue with 100 ml of cation exchange resin IRB
-120 and 100 ml of anion exchange resin I
The solution was passed through RA-410, concentrated to a concentration of 63%, transferred to a 1-liter crystallizer equipped with a stirrer, and cooled from 65 ° C to 40 ° C over 12 hours to obtain a slurry containing erythritol crystals. During this time, 1 g of erythritol crystals was added at 60 ° C. as a seed. The slurry was separated into erythritol crystals and a mother liquor by a centrifugal separator. The erythritol crystals were washed with a small amount of water, and then dried at 60 ° C. under reduced pressure to obtain 342 g of erythritol crystals. The purity of the erythritol crystals was 99.9%. A part of the erythritol crystals was dissolved in water to prepare an aqueous solution having a concentration of 30%. As a result, the solution was colorless and transparent, and no cloudiness was observed.

[0046]

Embodiment 4

An erythritol-containing fermentation broth from which cells were removed was prepared in the same manner as in Example 1.

[Crystallization] Crystallization was carried out in the same manner as in Example 2 to obtain one and two erythritol crystals, which were then dissolved in water to obtain an aqueous solution having a concentration of 40%.

[Hydrolysis] Using 7.4 g of phosphoric acid as the acid, heating at 120 ° C. for 60 minutes, adding 3 g of activated carbon, heating at 50 ° C. for 1 hour, and removing the activated carbon by filtration. Further, after passing through a column in which 200 ml of the cation exchange resin IRB-120 and 200 ml of the anion exchange resin IRA-410 were mixed, a concentration of 65% was obtained.
%, And erythritol was crystallized in the same manner as in Example 1 to obtain 347 g of erythritol crystals having a purity of 99.9%. A part of the obtained erythritol crystals was dissolved in water to prepare an aqueous solution having a concentration of 30%, but it was colorless and transparent, and no cloudiness was observed.

[0050]

[Comparative Example 1]

An erythritol-containing fermentation broth from which cells were removed was prepared in the same manner as in Example 1. To 10 liters of the resulting erythritol-containing fermentation broth, 7 g of activated carbon was added.
After heating at 0 ° C. for 1 hour, the activated carbon was removed by filtration. In addition, 500 ml of cation exchange resin IR
B-120 and 1 liter of anion exchange resin IRA-
After passing through 410, the solution was concentrated to a concentration of 65%,
After cooling to 35 ° C. over 8 hours, a slurry containing erythritol crystals was obtained. During this time, 1 g of erythritol crystals was added at 60 ° C. as a seed. The slurry was separated into erythritol crystals and a mother liquor by a centrifugal separator. The erythritol crystals were washed with a small amount of water, and then dried at 60 ° C. under reduced pressure to obtain 423 g of erythritol crystals. The purity of the erythritol crystals is 99.7%, and a part thereof is dissolved in water to prepare a 30% aqueous solution.
It contained apparently insoluble material and became cloudy white.

[0052]

【The invention's effect】

By carrying out the present invention, an erythritol-containing fermentation broth can be economically and easily purified.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiaki Tateno 1333-55, Atsuhara, Fuji City, Shizuoka Prefecture (72) Inventor Naoki Okamoto 186-2 Onemoto, Matsudo City, Chiba Prefecture

Claims (3)

[Claims] 1. A method for purifying erythritol, comprising recovering erythritol crystals by crystallization after acid-hydrolyzing an erythritol-containing fermentation solution after removing the cells. 2. A method for purifying erythritol, wherein erythritol crystals are recovered by crystallization from the erythritol-containing fermentation broth after removing the cells, and the obtained erythritol crystals are dissolved in water to acid-hydrolyze. 3. The method of claim 1, wherein the acid hydrolysis is performed by converting any one of sulfuric acid, hydrochloric acid and phosphoric acid into an acid hydrolyzate having an acid concentration of 0.1% by weight to 1.0% by weight. The method for purifying erythritol according to claim 1 or 2, wherein the erythritol is added at a temperature of 100 to 145 ° C.