JPH10287711A - Production of water-containing polyvinyl alcohol gel and production of molding on which enzyme or microorganism is immobilized - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-containing gel having excellent mechanical strengths by reacting a diacetoneacrylamide-copolymermodified polyvinyl alcohol resin containing a specified amount of diacetoneacrylamide units with a water-soluble hydrazine compound in an aqueous solution. SOLUTION: An aqueous solution containing 100 pts.wt. diacetoneacrylamide- copolymer-modified polyvinyl alcohol resin containing 0.1-15 mol% diacetoneacrylamide units is mixed with an aqueous solution containing 0.1-30 pts.wt. water-soluble hydrazine compound (e.g. hydrazine hydrate) and 0.05-1.0 mol/l of a polyvalentmetal-ion-containing compound (e.g. calcium chloride), and the resulting mixture is reacted to form a water-containing gel. An aqueous solution of a mixture of the modified polyvinyl alcohol resin with a water-soluble high-molecular polysaccharide (sodium alginate) containing an enzyme or microorganisms is mixed with an aqueous solution of a mixture of a water-soluble hydrazine compound with a polyvalent-metal-ion-containing compound, and the resulting mixture is reacted to form a gel containing immobilized enzyme or microorganisms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polyvinyl alcohol-based hydrogel having excellent moldability and strength, and an enzyme / hydrogel.
The present invention relates to a method for producing a microorganism-immobilized molded article.

[0002]

2. Description of the Related Art A hydrogel has little damage to living tissues,
Medical materials such as biomaterials such as eyes, skin and joints, and sustained-release carriers for drugs, because they are rich in substance permeability
It has been studied and put to practical use as a water retention agent and a cooling agent. In recent years, studies have been made to immobilize enzymes and microorganisms on hydrogels and use them as biocatalysts.

A water-containing gel using a polyvinyl alcohol (hereinafter abbreviated as PVA) resin has a high water content, a high flexibility of a molded product, a high mechanical strength, and a high affinity with a living body. It is a useful material in such respects.

Various methods are known for producing PVA-based hydrogel. For example, a method of freezing and dehydrating a PVA aqueous solution (JP-A-58-36630) and a method of repeating freezing and thawing of a PVA aqueous solution (JP-A-59-56446) have been proposed.
These methods require equipment for freezing the PVA aqueous solution, are complicated in operation, require a long time, and it is difficult to control the water resistance and strength of the gel. It is not an industrially advantageous method. In addition, a method of gelling a PVA aqueous solution by contacting the same with a saturated boric acid aqueous solution and a method of gelling a PVA aqueous solution by reacting an aldehyde compound have been known. The former is pH
It is necessary to carry out the reaction at a pH of 8.0 or more, and the obtained gel has a drawback that it is dissolved due to a change in pH, and the latter does not gel unless the pH is adjusted to 4.0 or less. Possible applications are limited, and immobilization of enzymes and microorganisms on hydrogels is difficult to apply.

[0005]

When the gel obtained by the above method is used as a biocatalyst carrier for microorganisms and enzymes, there is a problem that the activities of the microorganisms and enzymes are reduced by freezing and pH adjustment. there were.

An object of the present invention is to provide an industrially advantageous method for producing a hydrogel of a PVA resin which is excellent in mechanical strength and flexibility without lowering the activity of microorganisms and enzymes. It is.

[0007]

The present invention is characterized by reacting a water-soluble hydrazine compound with a diacetone acrylamide copolymerized PVA resin containing 0.1 to 15 mol% of diacetone acrylamide units in an aqueous solution. For producing a PVA-based hydrous gel, comprising:
A method for producing an enzyme / microorganism-immobilized molded article, which comprises immobilizing microorganisms, and further comprising contacting a diacetone acrylamide copolymer-modified PVA-based resin with at least one kind of polyvalent metal ion in addition to the enzymes / microorganisms. A method for producing an enzyme / microorganism-immobilized molded article, comprising dropping a mixed aqueous solution containing a water-soluble polymer polysaccharide having a gelling ability into an aqueous solution containing a polyvalent metal ion and a hydrazine compound. .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. The diacetone acrylamide copolymer-modified PVA used in the present invention can be produced by saponifying a polymer obtained by copolymerizing a fatty acid vinyl ester and diacetone acrylamide.

Examples of the fatty acid vinyl ester used in the above copolymerization include vinyl formate, vinyl acetate, vinyl propionate, and vinyl pivalate. Among them, vinyl acetate is industrially preferable, but is not limited thereto. Absent.

The above-mentioned copolymerization method of the fatty acid vinyl ester and diacetone acrylamide may be any of various polymerization methods known in the art such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization. Is preferably industrially used as a solvent.

As a method for saponifying a polymer obtained by copolymerizing a fatty acid vinyl ester and diacetone acrylamide, conventionally known alkali saponification and acid saponification can be applied. Industrially preferred is a method in which an alkali hydroxide is added to a mixed solution of methanol, water, methyl acetate, benzene, etc. to add alcohol and decompose.

The diacetone acrylamide copolymer modified PVA used in the present invention can be copolymerized with fatty acid vinyl ester or diacetone acrylamide, for example, crotonic acid, acrylic acid, methacrylic acid, as long as the effects of the present invention are not impaired. Unsaturated monocarboxylic acids such as acids and their esters, salts, anhydrides, amides and nitriles, unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid and salts thereof, and unsaturated monocarboxylic acids such as monomethyl maleate and monomethyl itaconate Saturated dibasic acid monoalkyl esters, α-olefins having 2 to 30 carbon atoms, alkyl vinyl ethers
It may be copolymerized with ters and vinylpyrrolidones. In addition, the obtained diacetone acrylamide copolymerized modified PVA was acetate-modified by inhibiting the effects of the present invention.
It may be post-modified by a reaction such as oxidation, urethanization, etherification, grafting, or phosphoric esterification.

The diacetone acrylamide copolymer modified PVA used in the present invention has a diacetone acrylamide unit content in the range of 0.1 to 15 mol%, preferably 0.5 to 10 mol%. If the content of diacetone acrylamide units is less than 0.1 mol%, the strength of the hydrogel is low. On the other hand, if the content is more than 15 mol%, the water solubility is reduced, causing a problem in work.

The degree of polymerization and the degree of saponification of the diacetone acrylamide copolymer-modified PVA used in the present invention can be various, but the viscosity of a 4% aqueous solution at 20 ° C. is 3 mPa · s or more, It is preferably at least 85 mol%.

As the water-soluble hydrazine compound used in the present invention, various compounds can be used, such as hydrazine, hydrazine hydrate, hydrazine monohydrate or salt, phenylhydrazine, methylhydrazine, ethylhydrazine, n Aromatic or aliphatic hydrazines such as -propylhydrazine, n-butylhydrazine, ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazine and salts thereof,
Monocarboxylic acid hydrazides such as benzoic acid hydrazide, formic acid hydrazide, acetate hydrazide, propionic acid hydrazide, n-butyric acid hydrazide, isobutyric acid hydrazide, n-valeric acid hydrazide, isovaleric acid hydrazide, pivalic acid hydrazide, and oxalic acid dihydrazide. Dihydrazide, succinic dihydrazide, glutaric dihydrazide, adipic dihydrazide, sebacic dihydrazide, maleic dihydrazide, fumaric dihydrazide,
Examples thereof include dicarboxylic acid dihydrazide such as itaconic acid dihydrazide, and polymer compounds having a hydrazino group such as dihydrazine carbonate and N-aminopolyacrylamide. These hydrazine compounds may be used alone or in combination.

Next, a method for producing the PVA-based hydrogel of the present invention will be described. The PVA-based hydrogel is obtained by reacting a diacetone acrylamide copolymer-modified PVA resin with a water-soluble hydrazine compound in an aqueous solution, and the mixing ratio of the diacetone acrylamide copolymer-modified PVA and the water-soluble hydrazine compound is diacetone. The amount is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight, based on 100 parts by weight of the acrylamide copolymer-modified PVA. The concentration of the diacetone acrylamide copolymerized modified PVA aqueous solution can be appropriately selected depending on the required gel strength, molding method, and the like.

Diacetone acrylamide copolymer modified PV
A and a water-soluble hydrazine compound when reacting
A solid hydrazine compound may be added to the A-based resin aqueous solution, or an aqueous solution of the hydrazine compound may be added. Alternatively, diacetone acrylamide copolymerized modified PVA formed by a conventionally known gel preparation method may be immersed in an aqueous solution of a hydrazine compound.

If necessary, the aqueous solution may contain PVA, starch, cellulose derivatives such as methylcellulose and carboxymethylcellulose, polyacrylic acid derivatives, gelatin, agar and carrageen, other than those used in the present invention. Other polymers such as Nan, sodium alginate, mannan, chitosan and thickeners, inorganic fillers such as clay, kaolin, talc, silica, calcium carbonate, glycerin, ethylene glycol, propylene glycol, sorbitol And at least one kind of activated sludge, microorganisms such as bacteria and yeasts, enzymes, etc., as long as the effects of the present invention are not impaired. it can.

Next, a method for producing the enzyme / microorganism-immobilized molded article of the present invention will be described. When immobilizing enzymes and microorganisms in a PVA-based hydrous gel, add at least one enzyme or microorganism to an aqueous solution of PVA-based resin before reacting the hydrazine compound with the diacetone acrylamide copolymerized modified PVA-based resin. Then, a hydrazine compound or an aqueous solution thereof is added and reacted to form a hydrogel, whereby an enzyme / microorganism-immobilized molded product can be obtained.

In the method for producing the enzyme / microorganism-immobilized molded article of the present invention, molded articles of various shapes can be obtained.
When the enzyme / microorganism-immobilized molded article is used as a bioreactor, the shape includes fluidity, filling effect, durability,
A spherical shape is advantageous from the viewpoint of handleability.

In order to produce a spherical hydrogel, a mixed solution containing an aqueous solution of a PVA-based resin, one or more enzymes, microorganisms and a hydrazine compound is poured into a spherical mold and gelled in the mold. Can be manufactured, but PV
A mixed aqueous solution containing a water-soluble polymer polysaccharide having a gelling ability upon contact with at least one kind of polyvalent metal ion in addition to one or more kinds of the A-based resin, the enzyme, and the microorganism, is used. It is industrially advantageous to use a method in which the compound is dropped into an aqueous solution containing a compound and becomes spherical by surface tension.

Examples of the water-soluble high molecular polysaccharide having a gelling ability upon contact with at least one polyvalent metal ion used in the present invention include sodium metal salt of alginic acid, carrageenan, mannan, chitosan and the like. But it is not limited to this. Among them, sodium alginate is particularly preferred.

Further, the microorganism used in the present invention includes:
Various types can be used, for example, filamentous fungi such as Aspergillus, Rhizopus, Pseudomonas, Acetobactor, Streptomyces.
ptomyces), Saccharomyces
Genus, Candida genus and other bacteria
Activated sludge containing more than one kind of microorganisms can also be used.

Various enzymes can be used, for example, various oxidases and reductors.
Enzymes such as enzyme, transferase, hydrolase, lyase, isomerase and ligase can be used alone or in combination of two or more.

In the method for producing the spherical enzyme / microorganism-immobilized molded article, first, a PVA-based mixed aqueous solution of a PVA-based resin and a water-soluble polymer polysaccharide is prepared. It is important to set an appropriate concentration according to the type and concentration of the additive component other than the PVA-based resin, the liquid temperature, and the dropping device. When the PVA-based mixed aqueous solution is used at room temperature, the concentration of the PVA-based resin in the PVA-based mixed aqueous solution is preferably 2 to 40% by weight from the viewpoint of the moldability and strength of the obtained PVA-based gel.

As the concentration of the PVA-based resin in the PVA-based mixed aqueous solution is higher, a stronger gel is formed.
If the concentration of the VA-based resin is too high, the viscosity of the solution also increases, and handling becomes difficult. Therefore, the lower the concentration of the PVA-based resin is, the more advantageous it is in a range where the required gel strength can be obtained.

Next, the concentration of the water-soluble polymer polysaccharide in the PVA-based mixed aqueous solution can be set to various concentrations, but differs depending on the type of the water-soluble polymer polysaccharide. Taking the most preferred sodium alginate as an example, the content is preferably 0.2 to 4% by weight, and
2% by weight is more preferred. Sodium alginate is 0.
If the amount is less than 2% by weight, the spheroidizing performance of the PVA-based mixed aqueous solution tends to decrease. May be high.

When a desired enzyme / microorganism is mixed and stirred into the mixed aqueous solution of the PVA resin and the water-soluble polymer polysaccharide, various concentrations can be adopted as the concentration of the enzyme / microorganism. , The concentration of bacterial solution containing enzymes and microorganisms,
The content is preferably in the range of 3 to 20% by weight based on the whole mixed aqueous solution. If the concentration of the enzyme or microorganism is too high, gel formation is hindered. If the concentration of the enzyme or microorganism is too low, the performance as a biocatalyst becomes unsatisfactory, which is not preferable.

Next, an aqueous solution containing a polyhydric metal ion-containing compound and a hydrazine compound used together with the above PVA-based mixed aqueous solution will be described.

As the polyvalent metal ion-containing compound, various compounds can be used. For example, magnesium ion, calcium ion, strontium ion,
Examples include compounds containing at least one of alkaline earth metal ions such as barium ion or polyvalent metal ions such as aluminum ion, cerium ion and nickel ion, and calcium chloride is particularly preferable. Further, the concentration of the polyvalent metal ion-containing compound may be various, but is preferably 0.05 to 1.0 mol / L.

As for the hydrazine compound, the various compounds described above can be used, and various concentrations can be used. -10% by weight is more preferred. If the concentration is less than 0.1% by weight, the strength of the gel decreases,
Although not preferred, a lower concentration is more cost effective as long as the required gel hardness is obtained.

The PVA-based mixed aqueous solution and the aqueous solution containing the polyvalent metal ion-containing compound and the hydrazine compound can be used at any temperature and pH.
It is preferable to adjust the temperature and pH to the optimum for the microorganism to form a gel.

The PVA-based mixed aqueous solution obtained as described above is dropped into an aqueous solution containing a polyvalent metal ion-containing compound and a hydrazine compound, and various means may be employed as the dropping method. For example, a method of filling a PVA-based mixed aqueous solution into a syringe and extruding it from a tubular base such as an injection needle and dropping it, or putting a PVA-based mixed aqueous solution into a container having a spray base and spraying from the spray base is given. be able to.

The dropped droplets of the PVA-based mixed aqueous solution are:
When it comes into contact with an aqueous solution containing a polyvalent metal ion-containing compound and a hydrazine compound, it becomes a sphere due to surface tension, and the outermost surface of the sphere solidifies into a thin film, and the viscosity of the PVA-based mixed aqueous solution is adjusted to adjust the viscosity of the PVA-based mixed aqueous solution. It can be arbitrarily changed to 20 mm. Polyvalent metal ion-containing compound,
The aqueous solution containing the hydrazine compound may be allowed to stand still, but by forcibly stirring with a stirrer or the like, the reaction between the molded product of the PVA-based mixed aqueous solution and the polyvalent metal ion-containing compound is promoted, and the spherical molded products are mixed. Fusion can be almost completely prevented.

Next, the molded product of the spheroidized PVA-based mixed aqueous solution is allowed to stand in an aqueous solution containing a hydrazine compound, whereby the diacetone acrylamide copolymer-modified P
The carbonyl group in VA reacts with the hydrazino group to form PVA.
The system resin is crosslinked to form a stable and strong gel. The standing time and temperature for gel formation differ depending on the type, concentration, pH value, etc. of the PVA-based resin and hydrazine compound.

The PVA gel thus obtained has a strength that does not deform or break over a long period of time, and can be used continuously without being affected by water or various chemicals. Since it can be produced at a pH optimum for microorganisms, it is highly practical as a highly active enzyme / microorganism-immobilized molded article.

[0037]

EXAMPLES The present invention will be specifically described below with reference to examples. In addition, each physical property in an Example is measured by the method described below.

1. The mechanical strength of the gel The gel molded product was allowed to stand on a flat surface, and it was observed whether or not the shape changed due to gravity, and whether or not the gel was collapsed by pressing the gel with a finger, and evaluated according to the following criteria. Evaluation criteria ○: The shape does not change due to gravity, and the gel does not collapse even when pressed with a finger. Δ: The shape did not change due to gravity, but the gel collapsed when pressed with a finger. ×: The gel was deformed by gravity. 2. Durability Add 300 g of water to 100 spherical gel moldings and add 3
The mixture was stirred at 0 ° C., the residual ratio of the gel after 7 days was measured, and evaluated according to the following criteria. Evaluation criteria ○: 95% or more △: less than 95%, 40% or more ×: less than 40%

3. Purification Performance Only the spherical gel molded products of Examples and Comparative Examples in which enzymes and microorganisms were immobilized were filled in a cylindrical container having a 15 cm diameter, 70 cm height entrance and exit closed with a mesh, to obtain a bioreactor. Wastewater having a COD concentration of 550 mg / L at normal temperature was passed through the bioreactor at a rate of 1.0 L / hour.
The COD concentration of the outlet-side purified water immediately after distribution and after 7 days has been measured and evaluated according to the following criteria. Evaluation criteria ○: less than 100 mg / L △: 100 mg / L or more, less than 500 mg / L ×: 500 mg / L or more Comprehensive evaluation The above evaluations were comprehensively evaluated according to the following criteria. Evaluation criteria ：: Gel strength, durability and purification performance are excellent. X: Gel strength, durability, and purification performance did not reach practical levels.

Synthesis Example 1 672 parts by weight of vinyl acetate, 10 parts by weight of diacetone acrylamide, and 178 parts of methanol were placed in a flask equipped with a stirrer, a thermometer, and a dropping funnel reflux condenser.
After charging parts by weight and purging with nitrogen in the system, the internal temperature was reduced to 6%.
The temperature was raised to 0 ° C. A solution prepared by dissolving 1 part by weight of 2,2-azobisisobutylylonitrile in 50 parts by weight of methanol was added to the system, and polymerization was started. A solution of 55 parts by weight of diacetone acrylamide dissolved in 35 parts by weight of methanol was dropped at a constant rate over 5 hours after the initiation of the polymerization.
After a lapse of time, m-dinitrobenzene was added as a polymerization inhibitor to terminate the polymerization. The polymerization yield was 78%. The remaining vinyl acetate was distilled out while adding methanol vapor to the obtained reaction mixture to obtain a 50% aqueous methanol solution of a vinyl acetate polymer containing a diacetone acrylamide copolymer component. 500 parts by weight of this mixture was added to methanol 5
0 parts by weight and a 4% methanol solution of sodium hydroxide 10
Parts by weight and mixed well, and a saponification reaction was carried out at 40 ° C. The obtained gel was pulverized, washed well with methanol, and dried to obtain a diacetone acrylamide copolymer modified PVA. In addition, elemental analysis revealed that the content of diacetone acrylamide units in this resin was 5.0 mol%. The viscosity of a 4% aqueous solution of this resin at 20 ° C. is 26.8 mPa · s, and the saponification degree is 98.
It was 4 mol%. The viscosity was measured at a rotation speed of 60 rpm using a B-type viscometer.

Synthetic Examples 2 to 5 Various diacetone acrylamide copolymerized polyvinyl alcohols shown in Table 1 were obtained in the same manner as in Synthetic Example 1 except that the charge composition was changed as shown in Table 1.

[0042]

[Table 1]

Example 1 10 g of diacetone acrylamide copolymerized PVA having a modification degree of 5.0 mol% obtained in Synthesis Example 1 was dissolved in 100 g of water, and 1 g of N-aminopolyacrylamide was added thereto. After stirring to form a uniform mixture, the mixture was poured into a spherical mold having a diameter of 1 cm and left at 10 ° C. for 2 hours to gel.

Table 2 shows the strength and durability of the obtained gel. The obtained gel showed excellent elasticity and flexibility even when pressed with a finger, did not collapse, and had excellent durability. In this example, since no microorganisms (microorganisms) were added, purification performance based on the action of microorganisms could not be expected, and thus evaluation of purification performance was omitted.

[0045]

[Table 2]

Example 2 10 g of diacetone acrylamide copolymer modified PVA having a degree of modification of 1.0 mol% obtained in Synthesis Example 2 was dissolved in 100 g of water, and 1 g of N-aminopolyacrylamide was added thereto. After stirring to form a uniform mixture, the mixture was poured into a spherical mold having a diameter of 1 cm and left at 10 ° C. for 2 hours to gel.

Table 2 shows the strength and durability of the obtained gel. The obtained gel showed excellent elasticity and flexibility even when pressed with a finger, did not collapse, and had excellent durability. In this example, since no microorganisms (microorganisms) were added, purification performance based on the action of microorganisms could not be expected, and thus evaluation of purification performance was omitted.

Example 3 10 g of diacetone acrylamide copolymer modified PVA having a degree of modification of 8.0 mol% obtained in Synthesis Example 3 was dissolved in 100 g of water, and 1 g of N-aminopolyacrylamide was added thereto. After stirring to form a uniform mixture, the mixture was poured into a spherical mold having a diameter of 1 cm and left at 10 ° C. for 2 hours to gel.

Table 2 shows the strength and durability of the obtained gel. The obtained gel showed excellent elasticity and flexibility even when pressed with a finger, did not collapse, and had excellent durability. In this example, since no microorganisms (microorganisms) were added, purification performance based on the action of microorganisms could not be expected, and thus evaluation of purification performance was omitted.

Example 4 A diacetone acrylamide copolymerized modified PVA resin having a modification degree of 5.0 mol% obtained in Synthesis Example 1 having a concentration of 10% by weight.
And add water to make the total amount 400 g.
After treating for 0 minutes to dissolve the PVA, it was allowed to cool to room temperature. To this, a 4% by weight aqueous sodium alginate solution 20
0 g was added and mixed well to prepare a PVA-based mixed aqueous solution. On the other hand, 11.1 g of calcium chloride and 50 g of N
-Aminopolyacrylamide was dissolved in 1 L of water to prepare an aqueous solution of a polyvalent metal compound and a hydrazine compound.

The above PVA-based mixed aqueous solution was sent at a rate of 1 mL / min by a roller pump using one vinyl tube having an inner diameter of 2 mm and attached to the tip thereof with a syringe needle having an inner diameter of 1 mm, and was then stirred by a stirrer. The aqueous solution of the above-mentioned polyvalent metal compound and hydrazine compound was dropped at a height of 15 cm from the water surface. The dropped solution immediately became spherical and settled.

Further, a spherical PVA gel was obtained by immersing the spheroidized molded product in an aqueous solution of a polyvalent metal compound and a hydrazine compound at 40 ° C. for 1 hour. The gel was not sticky and had a diameter of 3-4 mm. Table 2 shows the results of evaluating the gel strength and durability.
Shown in

As is clear from Table 2, the strength and durability were good. In this example, since no microorganisms (microorganisms) were added, purification performance based on the action of microorganisms could not be expected, and thus evaluation of purification performance was omitted.

Example 5 A spherical gel was prepared in the same manner as in Example 4 except that diacetone acrylamide copolymer modified PVA having a degree of modification of 1.0 mol% was used in Synthesis Example 2, and the gel strength and durability were evaluated. Was done. Table 2 shows the results. As is clear from Table 2, the strength and durability were good. In this example, since no microorganisms (microorganisms) were added, purification performance based on the action of microorganisms could not be expected, and thus evaluation of purification performance was omitted.

Example 6 A diacetone acrylamide copolymer-modified PVA resin having a modification degree of 5.0 mol% obtained in Synthesis Example 1 having a concentration of 10% by weight was used.
And add water to make the total amount 400 g.
After treating for 0 minutes to dissolve the PVA, it was allowed to cool to room temperature. To this, a 4% by weight aqueous sodium alginate solution 20
Add 0 g, mix well, and further add 60 g of activated sludge containing 0.5 g-wet cells / mL of Saccharomyces cells.
In addition, the mixture was sufficiently stirred to prepare a PVA-based mixed aqueous solution, and the pH was adjusted to 6.0 with sodium hydroxide. On the other hand, 11.
1 g of calcium chloride and 50 g of N-aminopolyacrylamide were dissolved in 1 L of water, hydrochloric acid was added, and p
An aqueous solution of a polyvalent metal compound of H6.0 and a hydrazine compound was prepared.

The PVA-based mixed aqueous solution was sent at a rate of 1 mL / min by a roller pump using one vinyl tube having an inner diameter of 2 mm and having a syringe needle having an inner diameter of 1 mm at the tip, and stirred with a stirrer. An aqueous solution of the above polyvalent metal compound and hydrazine compound was dropped at a height of 15 cm from the water surface. The dropped solution immediately became spherical and settled.

Further, a spherical PVA-based gel could be obtained by immersing the spheroidized molded product in a compound aqueous solution of a polyvalent metal compound and hydrazine at 40 ° C. for 1 hour. The gel was not sticky and had a diameter of 3-4 mm. Table 3 shows the results of evaluating the gel strength, durability and purification performance.

[0058]

[Table 3]

As is clear from Table 3, all of the strength, durability and purification performance were good.

Example 7 A spherical gel was prepared in the same manner as in Example 6, except that the diacetone acrylamide copolymer-modified PVA having a degree of modification of 1.0 mol% obtained in Synthesis Example 2 was used. The gel was not sticky and had a diameter of 3-4 mm. The gel strength, durability and purification performance were evaluated. Table 2 shows the results. Table 2
As is clear from the above, the strength, durability and purification performance were good.

Example 8 In preparing an aqueous solution of a polyvalent metal compound and a hydrazine compound, 5 g of N-aminoacrylamide was used instead of 50 g of N-aminoacrylamide.
A spherical gel was prepared in the same manner as in Example 6, except that 0 g of adipic dihydrazide was used. The gel was not sticky and had a diameter of 3-4 mm. The gel strength, durability and purification performance were evaluated. Table 3 shows the results. Table 3
As is clear from the above, the strength, durability and purification performance were good.

Example 9 A spherical gel was prepared in the same manner as in Example 6, except that the concentration of the aqueous solution of the PVA resin was changed to 5% by weight. The gel was not sticky and had a diameter of 1-2 mm. The gel strength, durability and purification performance were evaluated. Table 3 shows the results. As is clear from Table 3, the strength, durability and purification performance were good.

Example 10 A spherical gel was prepared in the same manner as in Example 6, except that the amount of N-aminoacrylamide used was changed to 10 g when preparing an aqueous solution of a polyvalent metal compound and a hydrazine compound. The gel was not sticky and had a diameter of 3-4 mm. The gel strength, durability and purification performance were evaluated. Table 3 shows the results. As is clear from Table 3, the strength, durability and purification performance were good.

COMPARATIVE EXAMPLE 1 10 g of diacetone acrylamide copolymer modified PVA having a degree of modification of 0.05 mol% obtained in Synthesis Example 4 was dissolved in 100 g of water, and 1 g of N-aminopolyacrylamide was added thereto. After stirring to form a uniform mixture, the mixture was poured into a spherical mold having a diameter of 1 cm and left at 10 ° C. for 2 hours, but did not gel.

Comparative Example 2 The diacetone acrylamide copolymer modified PVA having a modification degree of 18.0 mol% obtained in Synthesis Example 5 did not dissolve in water, so that a water-containing gel could not be prepared.

Comparative Example 3 Instead of the diacetone acrylamide copolymer-modified PVA resin obtained in Synthesis Example 1, the saponification degree was 98.5 mol%, and
A spherical gel was produced in the same manner as in Example 6, except that unmodified PVA having a 4% aqueous solution viscosity at 2 ° C. of 28.6 mPa · s was used. This gel is not sticky and has a diameter of 3 ~
4 mm. The gel strength, durability and purification performance were evaluated. The gel strength, durability and purification performance were evaluated. Table 3 shows the results. As is clear from Table 3, the gel strength was low and the durability was also problematic.

Comparative Example 4 Example 6 was repeated except that the diacetone acrylamide copolymer modified PVA resin obtained in Synthesis Example 4 was used instead of the diacetone acrylamide copolymer modified PVA resin obtained in Synthesis Example 1. A spherical gel was prepared in the same manner as described above. The gel was not sticky and had a diameter of 3-4 mm. The gel strength, durability and purification performance were evaluated. Table 3 shows the results
Shown in As is clear from Table 3, the gel strength was low and the durability was also problematic.

Comparative Example 5 A spherical gel was prepared in the same manner as in Example 6 except that no PVA resin was used, but no gel was obtained.

Comparative Example 6 Example 6 except that no N-aminoacrylamide was used.
A spherical gel was prepared in the same manner as described above. The gel was not sticky and had a diameter of 3-4 mm. The gel strength, durability and purification performance were evaluated. Table 3 shows the results. As is clear from Table 3, the gel strength was low and the durability was also problematic.

COMPARATIVE EXAMPLE 7 Except for using unmodified PVA having a saponification degree of 98.5 mol% and a 4% aqueous solution viscosity at 20 ° C. of 28.6 mPa · s, water was added to a concentration of 10% by weight, and the total amount was 400 g.
The mixture was treated at 95 ° C. for 120 minutes to dissolve the PVA, and then allowed to cool to room temperature. To this, 200 g of a 4% by weight aqueous sodium alginate solution was added and thoroughly mixed. Further, 60 g of activated sludge containing 0.5 g-wet clls / mL of the bacterium of the genus Saccharomyces was added, and the mixture was sufficiently stirred and mixed with a PVA-based mixed aqueous solution. Was prepared and adjusted to pH 6.0 with sodium hydroxide. On the other hand, 11.1 g of calcium chloride was added to and dissolved in 1 L of a saturated boric acid aqueous solution, and the pH was adjusted with hydrochloric acid.
An aqueous solution of boric acid and a polyvalent metal compound having a pH of 6.0 was prepared.

The PVA-based mixed aqueous solution was sent at a rate of 1 mL / min by a roller pump using a vinyl tube having an inner diameter of 1 mm and a needle having an inner diameter of 1 mm attached thereto and stirred with a stirrer. Was dropped from an aqueous solution of boric acid and a polyvalent metal compound at a height of 15 cm from the water surface. The dropped solution immediately became spherical and settled. Furthermore, a spherical PVA-based gel could be obtained by immersing the spheroidized molded product in an aqueous solution of boric acid and a polyvalent metal compound at 40 ° C. for 3 hours. The diameter of this gel was 3-4 mm. Table 3 shows the results of evaluating the gel strength, durability and purification performance.
Shown in As is clear from Table 3, the gel strength was weak,
There is also a problem in durability, which is considered to be because gelation of PVA by boric acid does not occur at the optimum pH of the microorganism.

Comparative Example 8 A spherical PVA gel was produced in the same manner as in Comparative Example 7, except that the pH of the PVA-based mixed aqueous solution and the aqueous solution of boric acid and the polyvalent metal compound were adjusted to 9.0. The diameter of this gel was 3-4 mm. Table 3 shows the results of evaluating the gel strength, durability and purification performance. As is clear from Table 3, the gel strength and durability were slightly inferior, and the COD concentration was 520 mg / L with respect to the purification performance, and it was found that almost no organic matter in the wastewater was purified. this is,
This is probably because the degradation activity of the bacterial cells was reduced due to a change in pH during the production of the PVA-based gel.

Comparative Example 9 10% by weight of unmodified PVA having a saponification degree of 98.5 mol% and a 4% aqueous solution at 20 ° C. having a viscosity of 28.6 mPa · s
And add water to make the total amount 400 g.
After treating for 0 minutes to dissolve the PVA, it was allowed to cool to room temperature. To this, a 4% by weight aqueous sodium alginate solution 20
0 g of the activated sludge containing 0.5 g-wet cells / mL of Saccharomyces sp.
g, and sufficiently stirred to produce a PVA-based mixed aqueous solution,
The pH was adjusted to 6.0 with sodium hydroxide. Meanwhile, 1
1.1 g of calcium chloride and 50 g of a 25% aqueous solution of glutaraldehyde are dissolved in 1 L of water, and the pH is further adjusted with hydrochloric acid.
An aqueous solution of a 6.0 polyvalent metal compound and glutaraldehyde was prepared.

The PVA-based mixed aqueous solution was sent at a rate of 1 mL / min by a roller pump using one vinyl tube having an inner diameter of 2 mm and having a needle having an inner diameter of 1 mm attached to the tip, and stirred with a stirrer. An aqueous solution of the above polyvalent metal compound and glutaraldehyde was dropped at a height of 15 cm from the water surface. The dropped solution immediately became spherical and settled. Furthermore, a spherical PVA-based gel could be obtained by immersing the spheroidized molded product in an aqueous solution of a polyvalent metal compound and glutaraldehyde at 40 ° C. for 3 hours. The diameter of this gel is 3
４4 mm. Table 3 shows the results of evaluating the gel strength, durability and purification performance.

As is evident from Table 3, the gel strength is low and the durability is problematic, which is due to the optimum pH of the microorganism.
It is considered that the gelation of PVA with glutaraldehyde did not occur.

Comparative Example 10 A spherical PVA-based gel was produced in the same manner as in Comparative Example 9 except that the pH of the PVA-based mixed aqueous solution and the aqueous solution of the polyvalent metal compound and glutaraldehyde were adjusted to 3.0. The diameter of this gel was 3-4 mm. Table 3 shows the results of evaluating the gel strength, durability and purification performance. Table 3
As is clear from the above, the gel strength and durability were good, but regarding the purification performance, the COD concentration was 510 mg / L.
It turned out that almost no organic matter in the wastewater was purified. This is considered to be due to a decrease in the activity of decomposing cells due to a change in pH during the production of the PVA-based gel.

[0077]

Industrial Applicability According to the present invention, it is possible to produce a PVA-based hydrogel having high strength which is industrially advantageous. When the obtained hydrogel is used as a carrier for immobilizing microorganisms and enzymes, the production of microorganisms and microorganisms at the time of production is improved. The desired activity can be maintained for a long period of time without reducing the activity of the enzyme.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 220: 56)

Claims (3)

[Claims] 1. A polyvinyl alcohol-based hydrogel characterized by reacting a water-soluble hydrazine compound with a diacetone acrylamide copolymerized modified polyvinyl alcohol-based resin containing 0.1 to 15 mol% of diacetone acrylamide units in an aqueous solution. Manufacturing method. 2. A method for producing an enzyme / microorganism-immobilized molded article, comprising immobilizing an enzyme / microorganism in the polyvinyl alcohol-based hydrogel according to claim 1. 3. A mixed aqueous solution containing a water-soluble high molecular weight polysaccharide having a gelling ability by contacting a diacetone acrylamide copolymerized modified polyvinyl alcohol resin with at least one kind of polyvalent metal ion in addition to enzymes and microorganisms. Is added dropwise to an aqueous solution containing a polyvalent metal ion and a hydrazine compound.