JPH0687954B2 - Selective separation method of coenzyme - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for selectively separating coenzymes.

(Prior Art) Enzymatic reaction is also partially industrially carried out in the process of manufacturing pharmaceuticals, foods, etc., and conventionally, the enzyme is dissolved in an aqueous solution of a substrate and the reaction is carried out in this aqueous solution. . But,
Some enzymes may require coenzymes to develop their catalytic activity. That is, as is well known, such an apoenzyme binds to a coenzyme and performs an enzymatic reaction as a holoenzyme, but in many cases, the binding between the coenzyme and the enzyme is reversible, And, because it is relatively weak, coenzymes are a common disposition for many similar reactions. Therefore,
When performing an enzymatic reaction industrially, it is necessary to separate and recover these enzymes and coenzymes from the product without deactivating their activity after the reaction, and to improve productivity and economic efficiency. Is essential to.

For this reason, many methods have already been proposed in which an enzyme or coenzyme is immobilized on a water-insoluble carrier, and after the required enzymatic reaction, this is separated from the reaction system by an ultrafiltration membrane. Immobilization of an enzyme generally requires a complicated chemical operation, and its activity is often lowered in the course of these chemical treatments, which in turn lowers the productivity and economical efficiency of the enzyme reaction.

Further, after the enzymatic reaction, it has also been proposed to directly separate the coenzyme from the reaction system with a semipermeable membrane, but according to a semipermeable membrane made of cellulose acetate or polysulfone that has been generally used, Since both the coenzyme and the reaction product are organic compounds of relatively low molecular weight, they are often removed to about the same degree, so that substantially only the coenzyme is selectively separated and recovered from the reaction system. It is difficult.

Furthermore, in the case of a semipermeable membrane made of cellulose acetate, it is difficult to use it for separating coenzyme from such a solution when the solution containing coenzyme is acidic or alkaline because of poor pH resistance. Furthermore, since the chlorine resistance and the heat resistance are poor, the method for washing the membrane after the coenzyme separation treatment is limited. Moreover, the semipermeable membrane cannot be heat-sterilized. On the other hand, an ultrafiltration membrane made of polysulfone is known as a semipermeable membrane having excellent pH resistance, chlorine resistance, heat resistance, etc.
However, since all of the conventional polysulfone ultrafiltration membranes have a large molecular weight cutoff, as described above, it is difficult to separate the reaction product from the coenzyme.

(Object of the Invention) As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a semipermeable membrane having a sulfonic acid group, particularly a skin layer having a solute separation activity, has a sulfonic acid group. , The composite semipermeable membrane, which is formed into an extremely thin thin film,
Due to its strong anionic property based on the sulfonic acid group, coenzymes with negative charge are prevented from permeating through mutual repulsion of charge, but are wide for neutral solutes and solutes with low chargeability. It has a substantially constant low removal rate in the concentration range, and because of its hydrophilicity based on sulfonic acid groups, the water permeation rate during membrane treatment is extremely high, so for example,
It was found that the coenzyme can be substantially selectively separated from the reaction system after the enzymatic reaction, and furthermore, by adjusting the pH of the solution containing the coenzyme, the difference in the charge number of the coenzyme can be utilized. Then, they have found that the coenzymes can be efficiently separated from each other, and have arrived at the present invention.

Therefore, an object of the present invention is to provide a method for selectively separating coenzyme, which can selectively separate and recover substantially only coenzyme from a solution containing coenzyme.

(Structure of the Invention) The method for selectively separating coenzyme according to the present invention is characterized by treating a solution containing coenzyme with a semipermeable membrane having a sulfonic acid group.

The semipermeable membrane having a sulfonic acid group used in the method of the present invention is a semipermeable membrane composed of a polymer in which the sulfonic acid group is the majority of all ion exchange groups, preferably 70% or more, particularly preferably 90% or more. is there. The remaining ion-exchange groups may be ion-exchange groups other than sulfonic acid groups, for example, carboxylic acid groups, as long as the sulfonic acid groups are in the above range of all ion-exchange groups.

In the present invention, as the semipermeable membrane having a sulfonic acid group, which can be particularly preferably used, the repeating unit A A sulfonated polyaryl ether obtained by sulfonation of a polyaryl ether consisting of
And repeating unit B (However, R represents —CO— or —SO ₂ —, R ′ represents a carbon-carbon bond or a divalent group.) A sulfonated polyaryl ether obtained by sulfonation of a linear polyaryl ether copolymer A composite semipermeable membrane in which a skin layer made of is integrally laminated on an ultrafiltration membrane as a supporting membrane can be mentioned.

Such a composite semipermeable membrane is preferably a sulfonated polyaryl ether comprising the above repeating unit A or a linear polyaryl ether copolymer comprising the above repeating unit A and a repeating unit B, respectively. An aryl ether is prepared, and an alkylene glycol alkyl ether such as ethylene glycol monomethyl ether, which may contain a small amount of an aprotic polar organic solvent, and a water-soluble and low-volatile organic compound as an additive, or It can be obtained by applying a film forming solvent containing an inorganic salt as an additive on a dried support film, and then evaporating an organic solvent from the film forming solution.

The above-mentioned sulfonated polyaryl ether can be obtained by treating the corresponding polyaryl ether with concentrated sulfuric acid, but in the present invention, the sulfonated polyaryl ether thus obtained has 0.5 g thereof. It is desirable that the solution of 100 ml of N-methyl-2-pyrrolidone has a logarithmic viscosity of 0.2 or more measured at a temperature of 30 ° C. and an ion exchange capacity of 2.3 meq / g or less. Ion exchange capacity is 2.3 meq / g
When it exceeds, the sulfonated polyaryl ether becomes water-soluble and is unsuitable as a material for a semipermeable membrane for treating an aqueous solution.When the logarithmic viscosity is less than 0.2, pinholes, etc. This is because it is difficult to form a uniform skin layer without defects.

When a skin layer is formed by using a sulfonated polyaryl ether obtained by sulfonation of the linear polyaryl ether copolymer, the linear polyaryl ether copolymer is repeatedly used at 10 mol% or more. It is preferably composed of the unit A and 90 mol% or less of the repeating unit B.

The sulfonic acid group contained in the sulfonated polyaryl ether used in the method of the present invention is represented by the formula —SO ₃ M, where M represents hydrogen, an alkali metal or tetraalkylammonium.

For example, after sulfonation of a polyaryl ether, the sulfonated polyaryl ether is washed with water and dried to obtain a sulfonated polyaryl ether having a free sulfonic acid group. Further, the sulfonic acid group can be converted into an alkali metal salt by treating the sulfonated polyaryl ether with an aqueous solution of an alkali metal hydroxide or an alkali metal alcoholate, a methanol solution, an ethanol solution, or the like. Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like, and examples of the alkali metal alcoholate include sodium methylate, potassium methylate, potassium ethylate and the like. Further, if the sulfonated polyaryl ether is treated in the same manner with a solution of tetraalkylammonium, for example, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, etc. The acid group can be the corresponding tetraalkylammonium salt.

The composite semipermeable membrane according to the present invention comprises the above-mentioned sulfonated polyaryl ether, a water-soluble and low-volatile compound as an additive, and an alkylene glycol alkyl which may contain a small amount of an aprotic polar organic solvent. It can be obtained by dissolving and containing in ether to form a film-forming solution, coating this on a dried support film, and then evaporating an organic solvent from the film-forming solution.

As the organic solvent for preparing the film-forming solvent, an alkylene glycol alkyl ether having an alkylene group having 2 to 4 carbon atoms and an alkyl group having 1 to 4 carbon atoms is particularly preferably used in the present invention. . This solvent has excellent solubility also in the sulfonated polyaryl ether used in the present invention and has high volatility, while it can be suitably used as a support membrane in the present invention. Because it does not dissolve. Specific examples of such alkylene glycol alkyl ethers include, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether,
Examples thereof include alkylene glycol monoalkyl ethers such as propylene glycol monoethyl ether, and alkylene glycol dialkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether and ethylene glycol diethyl ether. In particular, ethylene glycol monomethyl ether is preferably used because it has excellent solubility in sulfonated polyaryl ether and high volatility.

However, depending on the sulfonated polyaryl ether used, it may be difficult to dissolve it in the above alkylene glycol alkyl ether or it may simply swell. It has been found that it dissolves well in a mixed solvent prepared by adding a small amount of aprotic polar organic solvent to glycol alkyl ether. Examples of such aprotic polar organic solvent include dimethyl sulfoxide, N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-
Dimethylacetamide and the like are preferably used. In such a mixed solvent, the proportion of the aprotic polar organic solvent is preferably 5 parts by weight or less, particularly 3 parts by weight or less with respect to 100 parts by weight of the alkylene glycol alkyl ether. In the mixed solvent, when the aprotic polar organic solvent is more than 5 parts by weight with respect to 100 parts by weight of the alkylene glycol alkyl ether, when the membrane forming solution is applied on the dry polysulfone ultrafiltration membrane as the supporting membrane, Since this ultrafiltration membrane dissolves or swells,
This is because a composite semipermeable membrane with good performance cannot be obtained.

Thus, using a mixed solvent of alkylene glycol alkyl ether or a small amount of the aprotic polar organic solvent as the solvent for the film-forming solution, as described later, applied the film-forming solution to the supporting film. After that, in the step of removing the solvent from the film-forming solution by evaporation, substantially all the solvent can be removed by heating at room temperature to a slight amount, and a uniform thin film without defects can be obtained. It is advantageous.

The concentration of the sulfonated polyaryl ether in the membrane forming solution is also related to the thickness of the semipermeable membrane made of these polymers in the obtained composite semipermeable membrane, but is usually preferably in the range of 0.05 to 10% by weight, and particularly, The range of 0.1 to 5% by weight is preferable.

The film forming solution contains a specific additive. Among such additives, as the organic compound, at least one selected from the group consisting of polyhydric alcohols, polyalkylene glycols, carboxylic acids, salts thereof, hydroxycarboxylic acids and salts thereof is used. The organic compounds as these additives are water-soluble and have low volatility, and are required to be dissolved in the film-forming solution. Therefore, a polyhydric alcohol having 2 to 5 carbon atoms and a low molecular weight are required. The polyalkylene glycol, carboxylic acid, salt thereof, hydroxycarboxylic acid or salt thereof are preferably used. Specific examples include polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, and 1,4-butanediol; polyalkylene glycols such as diethylene glycol, triethylene glycol and dipropylene glycol; and carboxylic acids such as citric acid and citric acid. Examples thereof include acids and the like, hydroxycarboxylic acids such as lactic acid and hydroxybutyric acid, and salts of carboxylic acids and hydroxycarboxylic acids such as sodium salts and potassium salts.

Further, an inorganic salt which is water-soluble and is soluble in the film-forming solution can also be used as an additive. Examples of such inorganic salts include lithium chloride, lithium nitrate, magnesium perchlorate, and the like.

The concentration of these additives in the film forming solution is usually 0.1 to 8
It is in the range of 0% by weight. Although the effect of these additives on the formation of a composite semipermeable membrane is not always clear, it is related to the micropore size of the semipermeable membrane formed from the sulfonated polyarylether, and the membrane forming solution is used as a support membrane. When applied on a certain ultrafiltration membrane, the solvent and additives of the membrane-forming solution appear to modify the surface of the ultrafiltration membrane, thus
By selecting the type and amount of the additive used, according to the present invention, the performance of the composite semipermeable membrane, in particular, the removal rate for solute and the amount of membrane permeated water can be controlled in a wide range.

In the method of the present invention, the membrane-forming solution prepared as described above is then applied onto a dry ultrafiltration membrane as a supporting membrane. As is well known, a dry ultrafiltration membrane heats a wet ultrafiltration membrane prepared by a wet method to an appropriate temperature to evaporate and dry the water contained in the micropores of the membrane. It can be obtained.

In the above method, the ultrafiltration membrane as a support membrane for applying the membrane-forming solution is not particularly limited, but preferably an ultrafiltration membrane made of polysulfone, for example, the following formula C
Repeating unit And has a molecular weight cutoff of 1000-
An ultrafiltration membrane of 200,000, especially 50,000 to 150,000, is preferably used.

In the present invention, as described above, since a mixed solvent containing an alkylene glycol alkyl ether or a small amount of the aprotic polar organic solvent is used as the solvent for the film-forming solution, usually, without heating, It is possible to evaporate virtually all solvents at room temperature, but
After coating the film-forming solution on the support film, heating may be performed as necessary to evaporate the solvent. The heating temperature may be appropriately selected depending on the solvent used, but a temperature of 150 ° C. or lower is usually sufficient. In addition, in order to accelerate evaporation of the solvent after applying the film forming solution on the support film, the film forming solution may be heated in advance and applied on the support film.

The film thickness of the thin film semipermeable membrane based on the sulfonated polyaryl ether in the composite semipermeable membrane thus obtained depends on the concentration of these polymers in the membrane forming solution and the coating thickness of the membrane forming solution on the supporting membrane. Depending on the condition, it is preferable that the composite semipermeable membrane be thin to increase the water permeability, and thicker to increase the strength. Therefore, although not particularly limited, the semipermeable membrane having solute separation activity based on the sulfonated polyaryl ether preferably has a membrane thickness of usually 0.01 to 5 μm.

In the composite semipermeable membrane thus obtained, the additive may still remain in the membrane depending on the kind of the additive to be used, but the obtained composite semipermeable membrane is immersed in water and passed through Water and
Alternatively, immediate treatment of the aqueous liquid removes these additives from the membrane.

As described above, the skin layer having a thickness of 10 μm or less and having a sulfonic acid group and having separation performance is made of a sulfonated polyaryl ether, and the skin layer is integrally laminated on the support membrane. A sulfonated polyaryl ether composite semipermeable membrane can be obtained.

Thus, the composite semipermeable membrane made of the above-mentioned sulfonated polyaryl ether and having a skin layer whose thickness is preferably 10 μm or less has a high removal rate for coenzymes, and also has a neutral solute and an uncharged solute. It has a small removal rate for solutes having a low chargeability, and since the skin layer having separating activity is extremely thin, the water permeation rate for an aqueous solution containing a coenzyme is high. Furthermore, since it can be used over a wide pH range, the coenzymes can be separated from each other by adjusting the pH of the aqueous solution and utilizing the difference in the number of charges.

The method of the present invention can be applied to any coenzyme having a negative charge, but as a preferred specific example,
Examples include ATP (adenosine triphosphate), ADP (adenosine diphosphate), AMP (adenosine monophosphate), NADP (nicotinamide adenine dinucleotide phosphate), NAD (nicotinamide adenine dinucleotide), etc. it can.

In the method of the present invention, the treatment conditions of the aqueous solution are appropriately selected in consideration of the type and concentration of the solute together with the properties of the semipermeable membrane to be used, and such conditions are usually used in the technical field of aqueous solution membrane treatment. It can be easily selected. However, the membrane treatment temperature is usually in the range of 0 to 95 ° C. The higher the temperature, the higher the water permeation rate, but the activity of the coenzyme may decrease, so the temperature is preferably 5 to 70 ° C.
Is. Further, the higher the treatment pressure, the higher the water permeation rate, but it is usually in the range of 0.1 to 100 kg / cm ² .

Since the composite semipermeable membrane used in the method of the present invention has excellent chlorine resistance and heat resistance, an aqueous sodium hypochlorite solution can be used when the composite semipermeable membrane is washed. In particular, an aqueous solution having a sodium hypochlorite concentration of 1000 ppm or less can be preferably used. Further, the above-mentioned composite semipermeable membrane is, if necessary, at a temperature of up to 95 ° C,
If necessary, heat sterilization is also possible.

(Effect of the Invention) As described above, according to the method of the present invention, a semipermeable membrane having a sulfonic acid group, in particular, having a sulfonic acid group having an ultrathin film solute separation activity composed of a sulfonated polyaryl ether is used. The semipermeable membrane, due to its strong anionic property based on the sulfonic acid group, repulsively charges the coenzyme having a negative charge and blocks its permeation, but for a neutral solute and a solute having a small electric charge, It has a substantially constant low removal rate over a wide concentration range and further has hydrophilicity based on sulfonic acid groups, so that coenzyme can be substantially selectively separated from a solution containing coenzyme, and at the same time, The permeation rate of is also extremely high.

Therefore, the method of the present invention can be applied, for example, for selectively separating and recovering a coenzyme from a reaction mixture after an enzymatic reaction, although the mode of its application is not particularly limited. .

(Examples) Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples. In the examples, the solute removal rate and the water permeation rate were calculated by the following equations.

Example 1 (1) Production of sulfonated polysulfone Repeating unit A ₁ Polysulfone (10 g) was added to 97% concentrated sulfuric acid (80 ml), and the mixture was gently stirred and reacted at room temperature for 4 hours to obtain a blackish brown viscous reaction solution. This was put into an ice bath to solidify the sulfonated polysulfone. After washing with water, the mixture was left overnight in 800 ml of 0.5N aqueous sodium hydroxide solution. Then, the polymer was washed until the washing liquid became neutral.
Vacuum dried for an hour. The pale yellow granular sulfonated polysulfone thus obtained had an inherent viscosity of 3.00, sulfonic acid groups of 100% of all ion exchange groups, and an ion exchange capacity of 1.92 meq / g.

(2) Preparation of Composite Semipermeable Membrane An anisotropic ultrafiltration membrane comprising the repeating unit of the above formula C, having a removal rate of 10% for polyethylene glycol having an average molecular weight of 20,000 and having a molecular weight cutoff of 100,000 is used. 60 ° C
After drying at a temperature of, a dry ultrafiltration membrane for a supporting membrane was obtained.

After 0.8 g of the sulfonated polysulfone obtained above was dissolved in 79.2 g of ethylene glycol monomethyl ether, 20 g of lactic acid was added, and the polymer solution obtained by filtering with 10 μm filter paper was used as a film forming solution.

This membrane-forming solution was applied on the above dry ultrafiltration membrane, and most of the solvent was volatilized at room temperature and then heat-treated at a temperature of 60 ° C for 5 minutes to prepare a composite semi-layer having a skin layer of 0.5 µm in thickness. A permeable membrane was obtained.

The performance of this composite semipermeable membrane is that the removal rate is 10.0% and the water permeation rate is 6.2 m ³ / m ² when treated with a cutoff molecular weight of 10,000 and a 0.5% aqueous sodium chloride solution at 25 ° C and 50 kg / cm ^2. It was

The molecular weight cut-off here means the treatment of 0.05% aqueous solutions of polyethylene glycol having different molecular weights at 25 ° C and 20 kg / cm ² conditions, and the gel permeation of the polyethylene glycol when the removal rate is about 90%. It is the dextran-equivalent molecular weight measured by chromatography (GPC).

(3) Separation test of coenzyme 100 ml of a mixed solution containing ATP, ADP, AMP and adenosine (manufactured by Oriental Yeast Co., Ltd.) at a concentration of 2.5 mM each
After adding potassium hydroxide aqueous solution little by little to adjust the pH to 7, it was attached to a flat membrane tester (effective membrane area 11.3 cm ² ),
A permeation test was conducted at a pressure of 5 kg / cm ² and a temperature of 15 ° C.

As a result of analyzing the permeated liquid by liquid chromatography, the removal rate was 9 for each of ATP, ADP, AMP and adenosine.
It was 8.0%, 85.2%, 73.2% and 0%. The water transmission rate was 1.2 × 10 ^-3 / sec.

Example 2 (1) Production of Sulfonated Polysulfone Copolymer 57 mol% of the repeating unit of the formula A ₁ and repeating unit of the formula B ₁ 97 g of linear polysulfone copolymer consisting of 43 mol%
80% concentrated sulfuric acid was added and dissolved, and the mixture was stirred and reacted at room temperature for 4 hours to obtain a blackish brown viscous reaction liquid. This was put into an ice bath to solidify the sulfonated polysulfone copolymer. After washing with water, 800m of 0.5N sodium hydroxide solution
l left in overnight. Next, this polymer was washed until the washing liquid became neutral, and then vacuum dried at 60 ° C. for 5 hours.

The sulfonated polysulfone copolymer thus obtained had an inherent viscosity of 0.84, sulfonic acid groups of 100% of all ion exchange groups, and an ion exchange capacity of 1.2 mil-equivalent / g.

(2) Preparation of composite semipermeable membrane Obtained by dissolving 0.8 g of the linear sulfonated polystyrene copolymer obtained above in 79.2 g of ethylene glycol monomethyl ether, adding 20 g of glycerin, and filtering with 10 μm filter paper. The polymer solution was used as a film forming solution.

This membrane forming solution was applied on the same polysulfone dry ultrafiltration membrane as in Example 1, and most of the solvent was volatilized at room temperature,
Heat treatment was performed for 5 minutes at a temperature of 60 ° C. to obtain a composite semipermeable membrane having a skin layer having a thickness of 0.5 μm.

The performance of this composite semipermeable membrane is that the removal rate is 6.3% and the water permeation rate is 6.5 m ³ / m ² when treated with a cutoff molecular weight of 10,000 and a 0.5% aqueous sodium chloride solution at 25 ° C and 50 kg / cm ^2. It was

(3) Separation test of coenzyme The same coenzyme mixed aqueous solution used in Example 1 was used in Example 1.
The membrane was treated in the same manner as in.

As a result of analyzing the permeated liquid by liquid chromatography, the removal rate was 9 for each of ATP, ADP, AMP and adenosine.
The values were 7.0%, 84.8%, 72.4% and 0%. The water permeability was 1.2 × 10 ^-3 cm / sec.

The relationship between the pH of the aqueous solution containing the above coenzyme mixture and the removal rate of each coenzyme is shown in the drawing. It is understood that ATP and AMP can be effectively separated from adenosine by setting the pH to about 7 or higher. It is also understood that ATP and AMP can be separated from each other by adjusting the pH to about 4-6.

Example 3 (1) Production of sulfonated polyaryl ether ketone) Repeating unit A ₂ Polyaryletherketone consisting of (ICI PEEK 45
G) (10 g) was added to 97% concentrated sulfuric acid (80 ml), and the mixture was reacted at room temperature for 8 hours and then left at room temperature for 17 hours to obtain a concentrated sulfuric acid solution of the above polymer.

The above solution was thinly poured onto pure water cooled in an ice bath so as to pull a thread to solidify the polymer, which was collected by filtration and washed with pure water.
Washed twice. 1N sodium hydroxide solution 60 in this polymer
After adding 0 ml, the mixture was left standing for 3 hours, and then washed until the pH of the washing liquid reached 7. Then, the polymer was dried at 60 ° C. for 16 hours to obtain 11.6 g of a sulfonated polyaryl ether ketone. That this polymer is sulfonated. It was confirmed by its infrared absorption spectrum and nuclear magnetic resonance spectrum.

The ion exchange capacity of this polymer is 1.5 meq / g,
A solution of 0.5 g of N-methylpyrrolidone in 100 ml had an inherent viscosity of 1.30 measured at 30 ° C.

(2) Preparation of composite semipermeable membrane 9 g of the sulfonated polyaryl ether ketone obtained above was dissolved in 89.1 g of ethylene glycol monomethyl ether, 10 g of glycerin was added, and the solution was obtained by filtering with 10 μm filter paper. It was a membrane solution.

The above membrane-forming solution was applied on the same dry polysulfone ultrafiltration membrane as used in Example 1, and most of the solvent was volatilized at room temperature and then heat-treated at a temperature of 60 ° C. for 5 minutes,
A composite semipermeable membrane was obtained.

The performance of this composite semipermeable membrane is that the removal rate is 13.8% and the water permeation rate is 12.1 m ³ / m ² when treated with a cutoff molecular weight of 10,000 and a 0.5% aqueous sodium chloride solution at 25 ° C and 50 kg / cm ^2. It was

(3) Separation test of coenzyme The same coenzyme mixed aqueous solution used in Example 1 was used in Example 1.
The membrane was treated in the same manner as in.

As a result of analyzing the permeated liquid by liquid chromatography, the removal rate was 9 for each of ATP, ADP, AMP and adenosine.
It was 7.5%, 85.2%, 74.0% and 0%. The water permeability was 1.0 × 10 ^-3 cm / sec.

[Brief description of drawings]

The drawing is a graph showing the relationship between the pH of an aqueous solution and the removal rate of each coenzyme when an aqueous solution containing a coenzyme mixture is treated with a composite semipermeable membrane having a skin layer made of sulfonated polysulfone.

Claims (3)

[Claims] 1. A method for selectively separating coenzyme, which comprises treating a solution containing coenzyme with a semipermeable membrane having a sulfonic acid group. 2. A composite semi-permeable membrane having a sulfonic acid group, which comprises a thin film skin layer having a sulfonic acid group and having solute separation activity, and a support membrane integrally supporting the skin layer. The method for selectively separating coenzyme according to claim 1, which is a permeable membrane. 3. A composite semipermeable membrane having a sulfonic acid group has a repeating unit A. A sulfonated polyaryl ether obtained by sulfonation of a polyaryl ether consisting of
And repeating unit B (However, R represents —CO— or —SO ₂ —, R ′ represents a carbon-carbon bond or a divalent group.) A sulfonated polyaryl ether obtained by sulfonation of a linear polyaryl ether copolymer 3. The method for selectively separating coenzyme according to claim 2, wherein a skin layer having solute separation activity consisting of is integrally laminated on an ultrafiltration membrane as a supporting membrane.