JP2983655B2 - Diglyceride production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing diglycerides. More specifically, the present invention relates to a method for producing diglyceride by a two-step reaction in which an enzymatic method is used to react under excess glycerin and an insoluble glycerin is removed and reacted under dehydration.

[0002]

2. Description of the Related Art Among glycerides, monoglyceride and triglyceride have long been known for their industrial utility value, and many proposals have been made on their use and production technology.

[0003] However, diglycerides have received little attention, and have been treated as less useful products which are mixed with monoglycerides or triglycerides or are by-produced as intermediates. Therefore, diglycerides,
In particular, only a few proposals have been made on a method for producing high-purity diglyceride.

For example, Kakuta et al. Conduct esterification under dehydration using microbial alkaline lipase. The conditions were 1.7 moles of oleic acid per mole of glycerin, and lipase-PL 679 (manufactured by Meito Sangyo Co., Ltd.) as an enzyme.
Reacts with shaking at 40 ° C for 48 hours in the presence of 13.8% by weight. The ester synthesis rate of this reaction solution is reported to be 96% (JP-A-62-25987).

Also, Hirota et al. Conducted an esterification reaction of oleic acid in an amount of 2 moles per mole of glycerin using a lipase preparation under dehydration, and obtained an ester synthesis rate of 9 at 40 ° C. for 10 hours.
5.3% (JP-A-64-71495).

As a method for producing high-concentration diglycerides, in addition to the above, Yamane et al. (Japanese Patent Application Laid-Open No. 62-201591) and Hirota et al.
), But the diglyceride concentration is inferior to the above esterification reaction.

The esterification reaction of glycerin with a fatty acid is represented by the following reversible reaction formula.

[0008]

Embedded image

Wherein Gly is glycerin, FA is a fatty acid,
MG indicates monoglyceride and DG indicates diglyceride. ) (1)
From the formula (2), it is clear that the reaction proceeds to the hydrolysis side in a system with a large amount of water, and to the esterification reaction side in a system with a small amount of water. It is advantageous to carry out the reaction.

As a method for removing water, Japanese Patent Publication No. 63-1259
No. 9 discloses an esterification method in which a lipolytic enzyme having a transesterification activity is allowed to act on a substrate containing partial glyceride and free fatty acid or an ester of the lower alcohol in a system for discharging water or water and a lower alcohol, As a method for discharging water or water and lower alcohol to the outside of the system, use of an absorbent such as vacuum distillation or zeolite or silica gel is disclosed. The water content in the reaction system is 0.
It is described as about 18% or less.

Japanese Unexamined Patent Publication (Kokai) No. 60-203196 discloses a transesterification method using a lipase in which an ester synthesis reaction is carried out after a hydrolysis reaction of fats and oils. It is described that water is removed by continuously or intermittently ventilating the reaction system and exhausting the reaction system to remove the water in the reaction system together.

Japanese Unexamined Patent Publication (Kokai) No. 62-19090 discloses a method of adding specific water to glycerin and a saturated or unsaturated fatty acid having 2 to 22 carbon atoms without substantially adding water and further removing water by-produced by the reaction. It discloses a method of producing diglyceride by acting lipase produced by a mutant of Candida cylindrase having properties, and as a method of dehydrating the reaction system, using an absorbent, dry air or inactive It is disclosed that the gas is aerated and agitated into a reaction vessel and exhausted to the outside of the system to remove water to reduce the water content of the reaction system to 0.1% or less.

When an absorbent such as zeolite or silica gel is used in the above-mentioned dehydration method, the absorbent has a limited hygroscopic capacity. After saturation, the absorbent must be replaced with a new absorbent or the absorbent must be regenerated. Not industrially possible.
In addition, aeration and dehydration to the outside of the system by a dry airflow requires a large amount of dry airflow, and the equipment is industrially enlarged.

Therefore, the most suitable dehydration method for industrialization is distillation under reduced pressure. However, in consideration of enzyme stability, dehydration at a low temperature is required, and equipment with a high vacuum and a large amount of bleeding air is required. In the early stage of the reaction, a large amount of generated water is generated because the substrate concentration is high and the reaction rate is high. Therefore, in the conventional dehydration method using reduced pressure, dehydration cannot be performed efficiently in the initial stage of the reaction, and the reaction rate is degraded due to the dehydration rate control.

[0015]

Under such circumstances, the present inventors have found that in elucidating the reaction mechanism of the esterification reaction between fatty acids and glycerin, diglycerides, preferably high diglycerides, can be obtained with a completely new reaction method. The present inventors have found a production method for obtaining a diglyceride having a high concentration and completed the present invention.

That is, according to the present invention, in the ester synthesis reaction of a saturated or unsaturated fatty acid having 2 to 22 carbon atoms with glycerin, glycerin is added to the fatty acid in an equimolar amount or more to carry out the reaction (hereinafter referred to as glycerin excess reaction). ), A process for producing a diglyceride, wherein the reaction is stopped in a state where the concentration of a diglyceride as a product to be produced is increased, insoluble glycerin is separated, and the reaction is further carried out while being dehydrated (hereinafter referred to as a dehydration reaction). Is what you do.

The reaction of the present invention is an esterification reaction with glycerin and a fatty acid.
Heterogeneous reaction. Also, the product monoglyceride,
Diglyceride and triglyceride have a reaction form in which the fatty acid phase is a continuous phase and the glycerin phase is a dispersed phase by, for example, dissolving almost insoluble in the glycerin phase and dissolving in the fatty acid phase. That is, the reaction field was in the fatty acid phase, and it was found that glycerin dissolved in the fatty acid phase was involved in the reaction. When considering the water here, similarly, the water is involved in the reaction in the fatty acid phase, and the esterification rate is increased by removing the water in the fatty acid phase. Therefore, the glycerin droplet, which is a dispersed phase that does not directly affect the reaction, has water absorption, and by using this, the water generated by the reaction in the fatty acid phase, which is the continuous phase, is added as a dispersed phase, which is excessive. It was conceived to increase the esterification rate by moving to the glycerin droplet side. As a result of the study, it was found that by performing the reaction in the glycerin excess region, the dehydration rate was increased and the esterification rate was increased as compared with the conventional dehydration under reduced pressure.

Further, in order to carry out the method of the present invention suitably, the concentration of monoglyceride increases in the latter half of the reaction,
Based on the finding that diglyceride, which is the target product, is reduced, the reaction is stopped when the diglyceride concentration reaches a peak, preferably in a state where the diglyceride concentration reaches a peak, and glycerin containing product water that is insoluble in the fatty acid phase is removed. Remove by centrifugation or standing separation, remove the water as much as possible out of the system by depressurizing again only with the obtained fatty acid phase, which is a light liquid, and using a dehydration method such as molecular sieves dry air flow. The reaction was allowed to proceed to obtain a diglyceride reaction solution.

That is, according to the method of the present invention in which the above-mentioned glycerin excess reaction and dehydration reaction are combined, the time required for ester synthesis can be greatly reduced as compared with the conventional method, and a high concentration of diglyceride can be produced efficiently. You can.

Hereinafter, the present invention will be described in detail.

The fatty acid used in the present invention has 2 to 22 carbon atoms.
Saturated or unsaturated fatty acids, such as butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, zomaric acid, stearic acid,
Oleic acid, elaidic acid, linoleic acid, linolenic acid,
Arachidonic acid, gadrenic acid, arachinic acid, behenic acid, erucic acid and the like can be used. These fatty acids can be used alone or in combination of two or more.

In the present invention, the reaction is preferably performed in the presence of immobilized 1,3-position selective lipase or intracellular 1,3-position selective lipase. It can be obtained by immobilizing the 3-position selective lipase by a known method. Known methods for immobilization include, for example, "Immobilized Enzyme" edited by Ichiro Chibatake, Kodansha, pp. 9-85 and "Immobilized Biocatalyst" edited by Ichiro Chibatake, Kodansha, 12-101.
On the page, a method of immobilizing with an ion exchange resin is exemplified as a preferable method. As the 1,3-selective lipase used for immobilization, Rhizops (Rhizo
pus), Aspergillus, Mucor
Lipases derived from microorganisms of the genus (Mucor), pancreatic lipase, and the like. For example, Rhizopus delema
r), Rhizopus japonicus, Rhizopus niveus, Aspergillus niger, Mu-cor javanicus, Mucor mie
lipases of origin such as hei) can be used. Commercially available immobilized 1,3-position selective lipase is "Lipozyme3A" (trade name, manufactured by Novo Industries AS)
There is. Intracellular 1,3-position selective lipase is
1,3-position-selective lipase is adsorbed or bound, and a commercial product is "Olipase" (trade name, manufactured by Osaka Bacteria Research Institute). These immobilized or intracellular lipases need to exhibit a water retention ability in order to maintain their properties even under reduced pressure conditions. For this purpose, lipase immobilized with an ion exchange resin is particularly preferable.

A more specific preferred method of the present invention is as follows.

First, a saturated or unsaturated fatty acid having 2 to 22 carbon atoms and glycerin are reacted by adding glycerin in an equimolar amount or more to the fatty acid. Glycerin is preferably 1 to 50 mol, more preferably 1.25 to 1 mol per mol of fatty acid.
3.33 mol, and the mixture to which the lipase preparation was further added was 20 ° C to 100 ° C, preferably 40 to 70 ° C.
To carry out the reaction. The higher the molar ratio of glycerin to fatty acid, the lower the water content in the reaction field and the higher the esterification rate.However, when added in a large excess exceeding 50 moles, the transition between the continuous phase and the dispersed phase occurs, and the reaction becomes insoluble after the end of the reaction. A load is imposed on the separation of the hydrated glycerin, and disadvantages such as an increase in the size of the reaction tank occur, which is not preferable.

The reaction system is substantially non-aqueous except for the water contained in the lipase preparation. Hexane, octane,
Although a solvent such as petroleum ether can be used, it is preferable not to use a solvent in consideration of its removal and purification. The water content of the lipase preparation is 0.1 to 20% by weight, preferably 2 to 6% by weight.

Since the composition over time of the reaction is in the presence of excess glycerin, a glycerolysis reaction occurs in the latter half of the reaction, and the equilibrium shifts from the target product, diglyceride, to monoglyceride. Therefore, the lipase preparation is filtered off in such a region, and glycerin containing water produced, which is insoluble in the fatty acid phase, is removed by centrifugation or standing separation. The removed water-containing glycerin can be reused as raw glycerin by distillation under reduced pressure with an evaporator. The separated lipase preparation can be used repeatedly for the reaction.

In the above reaction, the esterification reaction proceeds sufficiently under normal pressure, but it may be used together with a method for removing generated water as much as possible.

In order to further increase the diglyceride concentration of the obtained fatty acid phase, the esterification reaction is further carried out using the lipase preparation in a state in which generated water is removed as much as possible.

After the completion of the above two-stage reaction, the lipase preparation is separated from the reaction product by filtration, and unreacted fatty acids and monoglycerides are easily removed by conventional or well-known separation and purification means such as molecular distillation alone or in combination. can do. Thus, purified diglyceride can be obtained with high purity and high yield. Further, the separated lipase preparation can be repeatedly used for the reaction.

By making this diglyceride production process continuous, the present invention can be more effectively applied. That is, FIG.
The process is as shown in the following.

In the reaction in the glycerin excess region, the reaction is continuously carried out using a reaction tower 1 charged with 6 as a starting fatty acid and 7 with glycerin and filled with a lipase preparation 13 as a flow tube reactor. That is, this makes it possible to dramatically increase the enzyme concentration, and has effects such as downsizing of the apparatus by increasing the reaction rate, increasing the efficiency, and suppressing triglyceride as a by-product. In the prior art in the diglyceride production method (Japanese Patent Application Laid-Open No. 62-25987), 0.1 mol per 1 mol of fatty acid is used.
Since it is a one-stage reaction using 45 to 1 mol of glycerin, when a flow tube type reactor is used, the reaction immediately reaches equilibrium,
Only low reaction rates are obtained.

Next, the hydrated glycerin 9 insoluble in the fatty acid phase is continuously separated by the centrifugal separator 2, and the hydrated glycerin is distilled by the vacuum evaporator 5 and reused as the raw material glycerin 10. The hydrated glycerin may be separated by stationary separation in order to separate the glycerin in a short period of time due to a difference in specific gravity.

In the dehydration reaction of the fatty acid phase, the reaction proceeds by circulating through the dehydrator 3 and the reaction tower 4 filled with the lipase preparation 14, and is continuously processed as a continuous tank type reactor to obtain a reaction finished product from the outlet 8. . In addition, 11 and 12 are vacuum lines.

[0034]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 A commercially available lipase preparation (lipase derived from Rhi-zopus japonicus, trade name "Lipase A-10", manufactured by Nagase & Co., Ltd., manufactured by Nagase & Co., Ltd.), which is a 1,3-position selective lipase, was prepared by Nakamura et al. G of immobilized lipase and 100 g of oleic acid obtained by immobilization according to the method (JP-A-1-174384).
(0.357 mol) and 43.8 g (0.476 mol) of glycerin,
The mixture was stirred at ℃ and reacted for 1.4 hours. After completion of the reaction, the immobilized lipase was separated by filtration, insoluble glycerin was removed by centrifugation, and a part of the remaining fatty acid phase was subjected to alkali titration to determine the ester synthesis rate. Further, a sample was partially taken, trimethylsilylated, and the composition of triglyceride, diglyceride and monoglyceride was determined by gas chromatography. The results are shown in Table 1 as the first reaction.

Next, 10 g of the above-mentioned immobilized lipase was mixed with 100 g of the reaction solution, and the mixture was stirred at 40 ° C. and reacted for 1.5 hours.
During the reaction, the pressure in the system was reduced to 5 mmHg in order to increase the diglyceride concentration. After the reaction, the immobilized lipase was separated by filtration, and then the ester synthesis rate and the glyceride composition were determined by the above method. The results are shown in Table 1 as the second reaction.

Example 2 10 g of the immobilized lipase of Example 1 and 100 g of oleic acid (0.3 g
57 mol) and 65.7 g (0.714 mol) of glycerin were mixed and stirred at 40 ° C. to carry out a reaction for 1.6 hours. Thereafter, the second reaction was carried out for 1.0 hour in the same manner as in Example 1. Table 1 shows the results.

Example 3 10 g of the immobilized lipase of Example 1 and 100 g of oleic acid (0.35
7 mol) and 100 g (1.087 mol) of glycerin, and the mixture was stirred at 40 ° C. and reacted for 1.8 hours. Thereafter, the second reaction was carried out for 0.5 hour in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 10 g of the immobilized lipase of Example 1 and 100 g of oleic acid (0.3 g
57 mol) and 16.4 g (0.179 mol) of glycerin were mixed and stirred at 40 ° C., and the reaction was carried out for 6.5 hours under reduced pressure of 5 mmHg in the system. Table 1 shows the results.

Comparative Example 2 The same reaction as in Comparative Example 1 was carried out except that the reaction time was changed to 3.0 hours. Table 1 shows the results.

[0041]

[Table 1]

Example 4 560 g of the immobilized lipase of Example 1 was added to the reaction column 1 shown in FIG.
And oleic acid is flowed through the charging port 6 at 1590 g / hr and glycerin is flowed through the charging port 7 at 1050 g / hr. After the steady state, the reaction solution was sampled, and after centrifugation, the upper layer was measured for the ester synthesis rate by the above-mentioned measurement method. The results are shown in Table 2 as the first reaction product.

The first reaction product obtained by centrifuging the reaction solution discharged from the reaction tower 1 by the centrifugal separator 2 was placed in a dehydrator 3 at 3 kg, and passed through the reaction tower 4 filled with 400 g of immobilized lipase. The reaction proceeds by returning to the dehydrator 3, that is, by circulating. Further, the first reaction product is continuously charged into the dehydrator 3 at 1840 g / hr, and the second reaction product is withdrawn from the outlet 8 while keeping the amount of liquid retained in the dehydrator constant. During the reaction, the pressure in the dehydrator 3 was reduced to 5 mmHg in order to increase the diglyceride concentration. Table 2 shows the ester synthesis ratio of the second reaction product.

Comparative Example 3 A continuous reaction is carried out only by the second reaction method in Example 4. The process is as shown in FIG. That is, oleic acid was charged into the dehydrator 15 from the charging port 24 at 1460 g / hr and glycerin was charged from the charging port 25 at 240 g / hr, and returned to the dehydrator 15 through the reaction tower 18 filled with immobilized lipase 21. Dehydrator
Drain the liquid so that the amount of retention in step 15 is constant. This reaction solution
Table 2 shows the ester synthesis rates of 26.

Since the reaction solution 26 has a low ester synthesis rate, it is similarly continuously supplied to the next dehydrator 16 and the reactor 19 filled with the immobilized lipase 22. Table 2 shows the ester synthesis rate of the reaction solution 27 obtained by the same method.

Similarly, the result of continuously supplying the reaction solution 27 to the next dehydrator 17 and the reactor 20 filled with the immobilized lipase 23 is shown in Table 2 as a reaction solution 28.

The dehydrators 15, 16, 17 are under a reduced pressure of 5 mmHg, and the reactors 18, 19, 20 are filled with 400 g of the immobilized lipase 21, 22, 23, respectively. In addition, the retention amount in each system is 3 kg. 29, 30, 31 are vacuum lines.

[0048]

[Table 2]

[0049]

According to the production method of the present invention, the dehydration efficiency is higher and the esterification reaction rate can be increased as compared with the conventionally proposed enzymatic method.

Further, according to the present invention, it is possible to make the manufacturing process a continuous system with high efficiency, and it is possible to make the apparatus compact and suppress by-products.

Further, in the method of the present invention, in the initial stage when a large amount of reaction product water is generated, the removal of the product water does not require any means such as reduced pressure, dry air flow, silica gel, etc. Therefore, an effect on lipase, that is, an improvement in enzyme stability can be expected. In addition, the reaction temperature proceeds at a low temperature in consideration of enzyme stability, but compared with the conventional method of removing generated water at a low temperature, after absorption by glycerin and separation,
The production method according to the present invention, in which hydrous glycerin can be distilled at a high temperature under reduced pressure, is more energy-saving.

In the industrialization plan, the dehydration rate is affected by the dehydrator liquid depth and the stirring intensity according to the decompression method. However, according to the method of the present invention, it is not necessary to consider the influence.

[Brief description of the drawings]

FIG. 1 is a diagram showing a preferred process of the manufacturing method of the present invention.

FIG. 2 is a view showing a process of a manufacturing method used in Comparative Example 3.

[Explanation of symbols]

 1: Reaction tower 2: Centrifuge 3: Dehydrator 4: Reaction tower 5: Distiller 6: Raw material fatty acid charging port 7: Raw material glycerin charging port 8: Reaction finished product outlet 9: Hydrous glycerin outlet 10: Glycerin recovered after distillation 11: vacuum line 12: vacuum line 13: immobilized lipase 14: immobilized lipase 15: dehydrator 16: dehydrator 17: dehydrator 18: reaction tower 19: reaction tower 20: reaction tower 21: immobilized lipase 22: immobilization Immobilized lipase 23: Immobilized lipase 24: Raw material fatty acid inlet 25: Raw material glycerin inlet 26: Reaction solution 27: Reaction solution 28: Reaction solution 29: Vacuum line 30: Vacuum line 31: Vacuum line

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-183396 (JP, A) JP-A-61-247390 (JP, A) JP-A-1-71495 (JP, A) JP-A-62-1987 25987 (JP, A) JP-A-63-133992 (JP, A) JP-A-62-19090 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C12P 7/64 BIOSIS ( DIALOG) CA (STN) JICST file (JOIS) REGISTRY (STN) WPI (DIALOG)

Claims (4)

(57) [Claims] In an ester synthesis reaction between a saturated or unsaturated fatty acid having 2 to 22 carbon atoms and glycerin, glycerin is added to the fatty acid in an equimolar amount or more to carry out a reaction (hereinafter, referred to as a glycerin excess zone reaction). A process for producing a diglyceride, comprising stopping the reaction in a state where the concentration of a target diglyceride is increased, separating insoluble glycerin, and further performing the reaction while dehydrating (hereinafter referred to as a dehydration reaction). 2. The addition ratio of a saturated or unsaturated fatty acid having 2 to 22 carbon atoms and glycerin to 1 mole of the fatty acid is
The method for producing diglyceride according to claim 1, wherein the amount of glycerin is 1 to 50 mol. 3. The method for producing diglyceride according to claim 1, wherein the reaction is performed in the presence of immobilized lipase or intracellular lipase. 4. A tube filled with immobilized lipase or intracellular lipase, which is continuously treated in one pass as a flow tube reactor in a reaction in an excess glycerin region, and a dehydrator in a subsequent dehydration reaction. 4. The method for producing diglyceride according to claim 3, wherein a dehydration reaction is carried out by circulating the enzyme filler and depressurizing the dehydrator to conduct the reaction continuously as a continuous tank reactor.