JPH0368601A - Immobil xized cyclodextrin - Google Patents

Abstract

PURPOSE:To facilitate recovery of adsorbed components and improve safety by chemically bonding a specific cyclodextrin having a formylated branch to an aminated carrier. CONSTITUTION:One mol of a branched cyclodextrin having a branched part comprising a saccharide and a cyclic part comprising alpha-, beta-, or gamma-cyclodextrin is mixed with 0.1-0.3mol of a guest compd. and allowed to stand for 1-24hr at room temp. to cause the branched cyclodextrin to include the guest compd. 0.001-1mol of a periodate is added to the resulting inclusion compd., which is then treated in an aq. solvent at 0-20 deg.C for 0.5-10hr and, if necessary, washed and purified to give a branched cyclodxetrin wherein only the branched part is formylated. The resulting cyclodextrin is reacted with a carrier comprising an aminated polysaccharide, protein, or aminated synthetic high-molecular substance in a molar ratio of the aldehyde group to the amino group of about 1:1 in an aq. medium for several hr to chemically bond the cyclodextrin to the carrier.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to novel immobilized cyclodextrins.

[Conventional technology]

Cyclodextrin is obtained by treating starch with cyclodextrin glucanotransferase, and is a cyclic oligosaccharide in which six or more glucose units are linked with α-1,4 bonds. α-cyclodextrin with 6 glucose rings, β-cyclodextrin with 7 glucose rings, and 8
A number of γ-cyclodextrins are known in one ship,
Each has 6 to 10 cavities. This cavity has the property of taking in various substances. The field of use is wide-ranging, including not only foods but also medicines and cosmetics.

However, cyclodextrins have low solubility when utilized in aqueous solutions, which severely limits their applications. In order to improve this drawback, research has been conducted on the production of branched cyclodextrins such as glucosylcyclodextrin, which has glucose molecules linked to the cyclodextrin ring with α-1,6 bonds, and maltosylcyclodextrin, which has maltose linked with α-1,6 bonds. Efficient manufacturing techniques have been disclosed in Japanese Patent Publications No. 61-92592, Japanese Patent Publication No. 70996/1987, and the like.

Although the solubility has been greatly improved by producing branched cyclodextrins, there is basically no difference in their uses and usage from conventional cyclodextrins. That is, as in the case of cyclodextrin, the target substance is included in the cavity of branched cyclodextrin in an aqueous solution,
A common treatment method is to collect and utilize the clathrated target substance after turning it into powder through a process such as drying or concentration.

However, it is difficult to handle and use the branched cyclodextrin containing the target substance in an aqueous solution by separating it outside the system and is expensive.

Therefore, a technology to immobilize cyclodextrin has been developed, making it possible to recover and separate target substances from aqueous solutions. For example, a method of cross-linking cyclodextrin with a cross-linking agent such as epichlorohydrin to form a bead-like polymer to adsorb and reduce bitter components in grapefruit juice and navel juiceCJ, ^gric, Food
Chem, 32.832-836 (1984)),
Cyclodextrin is immobilized on an acrylic resin carrier via a spacer, cyclodextrin is crosslinked using an acrylic resin as a crosslinking agent, and cyclodextrin is immobilized on a silica carrier via a spacer. etc.

However, when cyclodextrin is immobilized via a spacer, there is a problem in terms of cost when used industrially in large quantities. Furthermore, when a bead-shaped cyclodextrin polymer crosslinked with an acrylic resin is used for adsorption and fractionation of useful components in an aqueous solution, it takes time to recover the components adsorbed at the center of the beads. Furthermore, cyclodextrin polymers obtained with crosslinking agents such as epichlorohydrin have problems in terms of safety.

[Problem to be solved by the invention]

The purpose of the present invention is to facilitate recovery of adsorbed components,
An object of the present invention is to provide a novel immobilized cyclodextrin that has no problems in terms of safety.

[Means to solve the problem]

The above object is achieved by immobilized cyclodextrin, which is obtained by chemically bonding an aldehyded branched cyclodextrin, in which only the branched portion of the branched cyclodextrin is aldehyded, to a carrier having an amino group.

The branched cyclodextrin used in the present invention has a branch moiety such as glucosyl, maltosyl, vanosyl, etc., adjacent OH
Preferably, the saccharide has a cyclic group consisting of either αβ- or γ-cyclodextrin. These may be mono-branched cyclodextrins, homologous multi-branched cyclodextrins, or heterogeneous multi-branched cyclodextrins.

Examples of carriers having amino groups include amino group-containing polysaccharides or proteins, and amino group-containing synthetic polymer substances. Specific examples include natural products such as chitin and chitosan;
There are synthetic polymer substances such as weakly basic anion exchange resins.

In addition, amino group-containing polysaccharides include proteoglucans such as hyaluronic acid, chondroitin sulfate (chondroitin 4-sulfate, chondroitin 6-sulfate), dermatan sulfate, keratan sulfate, and their deacetylated products; proteins include albumin, Globulin, brolan, glycerin, histone, protamine, casein,
Synthetic polymers containing amino groups such as gelatin and collagen include polyacrylamide, polymethacrylamide, polyamide amines, 2-hydroxyethyl methacrylate having an amino group at one end, and synthetic polypeptides (poly L-lysine, poly L- arginine), etc.

In order to produce the aldehydated branched cyclodextrin used in the present invention, a suitable guest compound is first included in the branched cyclodextrin.

Examples of such guest compounds include butanol, cyclohexane, cyclohexanol, toluene, and the like. It is preferable to use about 0.1 to 0.3 mol of the guest compound per 1 mol of the branched cyclodextrin. When a branched cyclodextrin and a guest compound are mixed and left at room temperature for 1 to 24 hours, the guest compound is included.

After removing excess guest compound as necessary, this is then subjected to periodic acid oxidation treatment. periodic acid, periodate salt such as sodium metaperiodate, o, o o t~1
0 to 20°C in an aqueous solvent.
By treating for 5 to 10 hours, only the branched portions of the branched cyclodextrin are converted into aldehydes. 2 aldehyde groups when using glucosyl cyclodextrin, 2 or 4 aldehyde groups when using maltosyl cyclodextrin, 2 when using vanosyl cyclodextrin, 4 or 6 aldehyde groups are formed.

Next, excess periodic acid is decomposed by adding ethylene glycol, etc., and then adsorbed onto an activated carbon column and washed with water. After washing with water, elute with 15-50% ethanol and i! Purify by shrinkage and recrystallization.

When the aldehyde-branched cyclodextrin thus obtained and the carrier containing an amino group are reacted in an aqueous medium for several hours, the aldehyde and amine easily react and separate via the imino bond (-CH=N-). A branched cyclodextrin is immobilized on a carrier. The molar ratio of aldehyde groups to amino groups is not particularly limited, but is suitably 1:1. After completion of the immobilization reaction, it is desirable to reduce excess aldehyde groups with sodium borohydride or the like, and protect amino groups by acetylation.

[Effects of the Invention] The immobilized cyclodextrin of the present invention is obtained by chemically bonding a branched cyclodextrin in which only the branched portion is aldehyded to an amino group-containing carrier while retaining the inclusion function of the cyclodextrin. Since cyclodextrin is cheap and easy to manufacture, and cyclodextrin is immobilized on the surface of the carrier, useful and harmful substances can be effectively and easily recovered or removed. Furthermore, when natural substances such as chitin and chitosan are used as carriers, there is no problem in terms of safety. Furthermore, the immobilized cyclodextrin of the present invention can be used by filling a column in the same way as conventional ion exchange resins, etc., and can continuously adsorb and recover useful substances and harmful substances in aqueous solutions. I can do it.

Example 1 20-cyclohexane was added to 1.7 g of glucosyl β-cyclodextrin and left overnight to form inclusion. Add 950 ml of distilled water to this, stir well, add 0.1 mol of meta-periodic acid, add 50 ml of IJium solution, and let it stand at 5°C for 3 hours in the dark to oxidize with periodic acid. I let it happen.

Next, ethylene glycol 2rR1 was added and left to stand for 15 minutes to decompose excess sodium metaperiodate. Purification with an activated carbon column, elution with 15-50% ethanol, concentration to dryness and recrystallization yields β-cyclodextrin having an aldehyde group in the side chain.1. Obtained Og. Chitin 1 was obtained by dissolving this in 400ml of distilled water and partially deacetylating it.

Add g and stir with a magnetic stirrer for 3 hours.
Made it react. By centrifugation, 10.5 g of chitin with β-cyclodextrin immobilized on its surface was obtained. The weight content of cyclodextrin on the chitin surface of the main island was 5%.

After acetylation treatment to eliminate excess amino groups on the main island, 10 g of crystal was packed in a column and 0.1% naringin 30- was passed through the column. Approximately 29% more benaringin was removed compared to chitin, which has been deacetylated.

The amount of naringin was determined by colorimetrically quantifying the glucose produced by the action of naringinase (at 40° C. for 20 minutes) using the glucose oxidase method.

Example 2 T-glucosyl T-cyclodextrin having an aldehyde group in its side chain obtained by periodic acid oxidation of the branched portion of T-cyclodextrin
3g of cyclodextrin in 500ml of distilled water! It was dissolved in 30g of weakly basic anion exchange resin Amberlite rRA-45 was added to this, and the mixture was reacted for 3 hours while stirring with a stirrer.

Weakly basic anion exchange resin Amberlite IRA- on which branched T-cyclodextrin is immobilized by filtration.
45 (30.6 g) was obtained. When the amount of aldehyded T-cyclodextrin in the supernatant before and after the reaction was measured by the phenol-sulfuric acid method, it was found to have decreased by 25% after the reaction. Therefore, it can be seen that 25% of the aldehyded T-cyclodextrin used is bound to the resin.

In addition, the total amine content of crystal and weakly basic anion exchange resin Amberlite I RA-45 was 51 gg1a.

When confirmed by the Hanna and Kervenski method, the total number of amine moles in the crystal/sample (g) is 1.91X10
-', total amine moles of control/sample (g) is 2.79
It was X10-4. Therefore, it was confirmed that the amino groups of the weakly basic anion exchange resin Amberlite IRA-45 were reduced due to the Shipp base reaction.

Table 1 shows the physical properties of cyclodextrin having two aldehyde groups in its side chain, which is obtained by converting glucosyl cyclodextrin into aldehyde.

Claims (3)

[Claims] (1) An immobilized cyclodextrin characterized in that an aldehyded branched cyclodextrin, in which only the branched portion of the branched cyclodextrin is aldehyded, is chemically bonded to a carrier having an amino group. (2) The immobilized cyclodextrin according to claim (1), wherein the branched portion is a saccharide and the cyclic portion is α-, β- or γ-cyclodextrin. (3) The immobilized cyclodextrin according to claim (1), wherein the carrier having an amino group is an amino group-containing polysaccharide or protein, or an amino group-containing synthetic polymer substance.