JPS61187796A - Hydrolysis of fat and oil with lipase - Google Patents

Abstract

PURPOSE:Fat and oil is hydrolyzed using an aqueous lipase solution which previously contains glycerol to enable continuous hydrolysis of fat and oil in a practical scale without deterioration of the lipase solution. CONSTITUTION:In the hydrolysis tank 1, an oil melting lower than 40 deg.C such as olive oil, from tank 2 and an aqueous lipase solution of more than 50 units/ ml, containing previously at least 15wt% of glycerol, from tank 3 are brought into contact through a porous membrane 4 by allowing them to flow in the reverse directions at 10-40 deg.C. The fatty acid formed is recovered in tank 5 and the glycerol formed in the lipase solution is recovered through filter 6 and glycerol concentrator 7 into tank 8. Thus, while glycerol is recovered, more than half of the lipase solution is recycled and water is fed from tank 9 to adjust the amount of glycerol in the lipase solution so that it becomes totally lower than 25wt% for hydrolysis.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for hydrolyzing fats and oils using lipase, and more specifically to a method for hydrolyzing fats and oils into fatty acids and glycerol by contacting them with an aqueous lipase solution.

[Conventional technology]

As one method for hydrolyzing fats and oils with lipase, a method using lipase immobilized on a carrier is being considered from the viewpoint of easy recovery and reuse of expensive lipase, but this method requires a complicated immobilization operation. However, it also has drawbacks such as high immobilization costs, low expression rate of lipase activity, and difficulty in carrying out efficient heterogeneous reactions, which are major reasons for hindering its practical application.

On the other hand, the method of using an aqueous solution of lipase dissolved in water and bringing it into contact with fats and oils to carry out a hydrolysis reaction does not have the above-mentioned drawbacks and is a method that is easier to put into practical use, and has recently been put into practical use. Many proposals have been made regarding how best to recover and utilize lipase.

In the method using this aqueous lipase solution, in a batch method,
A method is known in which a predetermined amount of lipase aqueous solution and oil are mixed in a liquid state or in a semi-solid slurry state using an emulsifier by stirring until the required hydrolysis rate is reached. As a method that can be used particularly advantageously, the present applicant previously proposed Japanese Patent Application Laid-open No. 59-154.
The method described in Publication No. 999 (hereinafter referred to as the proposed method)
1) and Japanese Patent Application Laid-Open No. 1983-1981 proposed by Masato Nishimura et al.
A method described in Japanese Patent No. 210893 (hereinafter referred to as proposed method-2) is known.

The above proposed method 1 is a hydrolysis method characterized by bringing an aqueous lipase solution into contact with fats and oils through a porous thin film (see Figure 1), and the above proposed method 2 is a hydrolysis method characterized by bringing an aqueous lipase solution into contact with fats and oils through a porous thin film (see Figure 1). This is a hydrolysis method characterized by introducing fats and oils in the form of fine oil droplets and allowing them to react while being floated in a dispersed state (see Figure 2). In both of these proposed methods, separation of fatty acids and glycerol produced by hydrolysis and recovery and utilization of lipase from an aqueous lipase solution are easy, and such separation and recovery steps can be integrated into the hydrolysis reaction step. This enables continuous hydrolysis of fats and oils.

[Problems to be solved by the invention] As described above, the method of hydrolyzing fats and oils using an aqueous lipase solution is currently undergoing a transition from a batch method to a continuous method, and steady studies are being made toward its practical application. It is progressing. However, lipase is a type of enzyme or protein, and when it is used in the form of an aqueous solution, the following problems cannot be avoided.

That is, the hydrolysis reaction of fats and oils by lipase, like other enzymatic reactions, is generally carried out at a temperature around or slightly higher than room temperature, practically at a temperature of 30 to 40°C. This temperature is a condition in which microorganisms easily grow, and lipase as a protein serves as a nutritional source for microorganisms, so an aqueous lipase solution prepared by dissolving this lipase in water will deteriorate over time due to microbial growth.

The problem is that this spoilage phenomenon occurs earlier than the required enzymatic or hydrolysis reactions.

For example, a hydrolysis reaction using a lipase aqueous solution in a batch process requires 3 to 7 days at 30 to 40°C, whereas clouding of the lipase aqueous solution due to microbial growth occurs in 2 to 3 days at the same temperature.

Needless to say, such spoilage of the lipase aqueous solution not only definitely inhibits the hydrolysis reaction by lipase, but also
This can also lead to side reactions caused by spoilage bacteria, giving rise to undesirable products. Moreover, in the continuous method, this is originally intended for long-term operation, and especially in the proposed method -
In methods such as 1 and 2, in which the product recovery process and the lipase recovery process are integrated into the hydrolysis reaction process, it is necessary to take into account spoilage phenomena in the entire line, including the lipase storage tank. How to overcome the above-mentioned problems will be an extremely important issue at the stage of practical application.

Therefore, the present invention can prevent spoilage of the aqueous solution for a long period of time in a method for hydrolyzing fats and oils using an aqueous lipase solution, and in particular, it can practically make it possible to put into practical use continuous methods such as the above-mentioned proposed methods 1 and 2. The purpose is to provide an industrially useful hydrolysis method.

[Means for solving problems]

As a result of intensive studies to achieve the above object, the inventor found that glycerol effectively contributes to preventing spoilage of a lipase aqueous solution, and that glycerol can be added in a large amount of at least 15% by weight to a lipase aqueous solution. ,
It has been found that spoilage of the above aqueous solution can be prevented for a long period of time.

It is already known that lipase in an aqueous lipase solution is stabilized by polyhydric alcohols such as ethylene glycol and glycerol. However, this stabilization is only meant to prevent a decrease in the activation rate of lipase itself in an aqueous solution, and the amount of polyhydric alkonyl added is necessary for this purpose.
The amount is as small as 0M% or less, and with such a small amount, it is not possible to prevent the aqueous solution from spoiling due to microbial growth, which is the object of the present invention.

In addition, in the hydrolysis reaction of fats and oils using an aqueous lipase solution, glycerol produced by the hydrolysis dissolves in the aqueous lipase solution, but in this type of reaction, the amount of fats and oils to be processed is limited to the aqueous lipase solution due to its reactivity. In contrast, the amount of glycerol dissolved in the aqueous solution does not exceed 0% by weight per month, and in particular, in continuous systems such as the proposed methods 1 and 2, the amount is usually 2.3% by weight or less. Furthermore, in the continuous method described above, the recovered lipase is circulated and supplied into the reaction system as an aqueous solution containing even less dissolved glycerol, so the spoilage of the lipase aqueous solution in the entire line including the circulation system and the reaction system is prevented by hydrolysis. It cannot be prevented by the glycerol produced by

In other words, in the hydrolysis reaction of fats and oils using an aqueous lipase solution, the inventor added at least 15% by weight of glycerol, which is considerably larger than the amount of glycerol produced by this hydrolysis, to the aqueous lipase solution before contacting it with the fats and oils. They have discovered that by dissolving the aqueous solution in advance, it is possible to effectively prevent the aqueous solution from spoiling in the reaction system and further in the circulation system.

On the other hand, in the hydrolysis of fats and oils accompanied by the production of glycerol,
Excess glycerol in the reaction system may inhibit the progress of the reaction itself. However, after extensive experimental studies, the inventor found that if the amount of dissolved glycerol in the lipase aqueous solution exceeds 25% by weight, the above-mentioned inhibition phenomenon becomes noticeable, but if the amount is less than 25% by weight, the hydration by dissolved glycerol is reduced. No inhibition phenomenon of decomposition reaction was observed.
It was found that the process progresses effectively.

This invention has been made based on the above findings, and the gist thereof is to provide a method for hydrolyzing fats and oils into fatty acids and glycerol by contacting them with an aqueous lipase solution, before subjecting them to hydrolysis. At least 15% by weight of glycerol is dissolved in the lipase aqueous solution in advance, and the above hydrolysis is carried out so that the total amount of this dissolved glycerol and the glycerol produced by hydrolysis is 25% by weight or less in the lipase aqueous solution. A method for hydrolyzing fats and oils using lipase, which is characterized by the following.

As described above, the present invention can prevent spoilage of the aqueous solution by including glycerol in an aqueous lipase solution of 15% by weight or more and 25% by weight or less, while preventing reaction inhibition caused by dissolved glycerol. ,
It is characterized by a scale that allows a stable hydrolysis reaction to occur over a long period of time. Therefore, by applying this method to a continuous method such as the above-mentioned proposed methods 1 and 2, the recovered lipase can be absorbed not only in the reaction system but also in the reaction system. The lipase aqueous solution is prevented from spoiling in the circulatory system for circulating supply.
This makes it practically possible to put these systems into practical use for long-term operation.

The type of lipase used in this invention is not particularly limited, but in general, lipases sourced from microorganisms such as Candida, Chromobacterium, Aspergillus, Henicillium, Geotrichum, and Rhizopus, as well as pancreatic Lipases obtained from animal organs such as, lipases obtained from plant seeds such as castor seeds, etc. can be used.

The concentration of the lipase aqueous solution is not particularly limited and can be selected freely, and the higher the concentration, the faster the hydrolysis reaction proceeds. From a practical standpoint, the above concentration is 50 units/mβ or more, especially 200 units/m1
It is preferable that it is above.

In the case of ordinary lipase, the temperature for the hydrolysis reaction of fats and oils is generally 10 to 10% from the viewpoint of both prevention of deactivation and reaction rate.
A range of 45°C is preferred; however, for thermostable lipases, higher temperatures may be applied to improve the rate of hydrolysis.

In the batch method or continuous method, in which the substrate is brought into contact with the lipase aqueous solution in a liquid state, the fat or oil that has a melting point below the hydrolysis reaction temperature, that is, in the case of using ordinary lipase, a fat or oil with a melting point of about 40°C or less, For example, vegetable oils include olive oil, flaxseed oil, safflower oil, soybean oil,
Animal fats such as tung oil, lard, and fish oil can be used. When using heat-stable lipase, palm oil, beef tallow, etc. can also be used. Furthermore, in a batch method in which the solid state is brought into contact with the lipase aqueous solution, any oil or fat with a high melting point other than those mentioned above can also be used.

〔Example〕

Next, an example will be described in which the method of the present invention is applied to the continuous hydrolysis method of the above-mentioned proposed methods 1 and 2.

Example 1 Figure 1 shows a schematic diagram of a continuous system according to proposed method-1, in which oil and fat and lipase aqueous solution are introduced into a hydrolysis reaction tank 1 from an oil tank 2 and a lipase aqueous solution tank 3 in opposite directions. contact is made via the porous thin film 4. Due to this contact, the hydrolysis reaction progresses, and the generated fatty acids are transferred to the fatty acid tank 5.
The produced glycerol is recovered into the glycerol tank 8 via the lipase recovery ultrafiltration device 6 and the glycerol concentration (purification/distillation) device 7. Here, the reaction tank 1 A portion of the lipase aqueous solution derived is led to the glycerol recovery system, while the majority is circulated and supplied to the reaction tank 1 again via the lipase aqueous solution tank 3.

The lipase aqueous solution tank 3 is supplied with recovered lipase from the lipase recovery ultrafiltration device 6 and water from the water tank 9 (or glycerol concentrator 7 in some cases) to maintain a constant lipase concentration and predetermined glycerol concentration. be adjusted.

By this hydrolysis method, olive oil (acid value 1.8, saponification value 190.1) is used as the fat and oil, and a lipase solution containing 1.000 units/ml of Candida lipase and a predetermined concentration of glycerol is used as the lipase aqueous solution. At the same time, a polypropylene microporous membrane was used as the porous thin membrane 4, and continuous operation was actually performed at a reaction system temperature of 40°C. Glycerol concentration in lipase aqueous solution is 0 to 40.
The results of examining the relationship between the hydrolysis rate (%) and the number of operating days at each concentration were as shown in FIG. 3. Symbols A to F in the figure indicate the glycerol concentrations in 1 ffl of the lipase aqueous solution set as shown below.

Code A: 0% by weight Code B: 9% by weight Code C: 18% by weight Code D: 23% by weight Code E: 29% by weight Code F: 37% by weight As is clear from the results in Figure 3, when the glycerol concentration in the lipase aqueous solution is within the range of 15 to 25% by weight, the hydrolysis rate is 90% even after 20 days of long-term operation.
However, if it is less than 15% by weight, it will be spoiled by microorganisms, and if it exceeds 25% by weight, it will not be possible to maintain a high hydrolysis rate for a long period of time due to reaction inhibition of glycerol. It turns out that it is something.

Example 2 The second plan shows a schematic diagram of a continuous system according to proposed method-2, in which fats and oils and lipase aqueous solution are introduced into the hydrolysis reaction tank 10 from the fats and oils tank 20 and the lipase aqueous solution tank 30, and the above-mentioned fats and oils are introduced. A catalytic reaction is carried out so that the particles float in a dispersed state as fine oil droplets in the lipase aqueous solution. The fatty acids produced in this reaction are collected in the fatty acid tank 50 via the microfiltration device 40 for oil/water separation, and the produced glycerol dissolved in the lipase aqueous solution is collected by the ultrafiltration device 6 for lipase recovery.
0 and is collected into a glycerol tank 80 via a glycerol concentration (purification/distillation) device 70. Here, part of the lipase aqueous solution that has passed through the lipase recovery ultrafiltration device 60 is guided to the glycerol concentrator 70, while the majority is circulated and supplied to the reaction tank 10 again via the lipase aqueous solution tank 30. Ru. The above lipase aqueous solution tank 30
Now, the recovered lipase from the lipase recovery ultrafiltration device 60 and the water tank 90 (in some cases, the glycerol concentrator 7
water from 0) is supplied and adjusted to a constant lipase concentration and a predetermined glycerol concentration.

Using this hydrolysis method, olive oil (acid value 1.8, saponification value 190.1) is used as the fat and oil, and a lipase solution containing 1,000 units/ml of parse belonging to Candida and having a predetermined concentration of glycerol is used as the lipase aqueous solution. Then, continuous operation was actually carried out at a reaction system temperature of 40°C.

The supply of olive oil to the reaction tank 10 was repeated 20 times using the oil circulation system 100 over a period of about 10 minutes, and new olive oil was supplied one after another.

In this continuous operation, the glycerol concentration in the lipase aqueous solution was varied from 0 to 40% by weight, and the relationship between the hydrolysis rate (%) and the number of operating days at each concentration was investigated. The results are shown in Figure 4. Met.

Symbols G to L in the figure indicate the glycerol concentrations in the lipase aqueous solution, each set as follows.

Code G: 0% by weight Code H: 10% by weight Code I: 16% by weight Code J: 23% by weight Code K: 30% by weight Code L: 39% by weight Above No. As is clear from the results in Figure 4, when the glycerol concentration in the lipase aqueous solution is within the range of 15 to 25% by weight, the hydrolysis rate is 80% even after 20 days of long-term operation.
However, if it is less than 15% by weight, it will be spoiled by microorganisms, and if it exceeds 25% by weight, it will not be possible to maintain a high hydrolysis rate for a long period of time due to reaction inhibition of glycerol. It turns out that it is something.

〔Effect of the invention〕

As described above, according to the present invention, the lipase aqueous solution can be prevented from being putrefied by microorganisms and the hydrolyzing ability of the lipase can be maintained for a long period of time. Law-1,
This can greatly contribute to the practical application of continuous hydrolysis methods such as 2.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing an example of a continuous hydrolysis method for fats and oils using an aqueous lipase solution, Figure 2 is a schematic diagram showing another example of the above, and Figure 3 is a schematic diagram showing an example of the continuous hydrolysis method of fats and oils using an aqueous lipase solution. Performance diagram showing the relationship between the decomposition rate and the number of continuous operation days. FIG. 4 is a performance diagram showing the relationship between the hydrolysis rate and the number of continuous operation days in the continuous hydrolysis method of FIG. 2. Figure 3 Figure 4 Number of continuous operation days! (Day)

Claims (1)

[Claims] (1) In a method of hydrolyzing fats and oils into fatty acids and glycerol by contacting them with an aqueous lipase solution, at least 15% by weight of the aqueous lipase solution is added in advance to the aqueous lipase solution before being subjected to hydrolysis.
of fats and oils with lipase is dissolved, and the hydrolysis is carried out so that the total amount of the dissolved glycerol and the glycerol produced by hydrolysis is 25% by weight or less in the lipase aqueous solution. Hydrolysis method.