JPH04502171A - How to produce chitosan - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] How to produce chitosan The present invention relates to an improved method for producing chitosan by deacetylating chitin. Ru.

Chitosan is traditionally derived from chitosan derived from the exoskeleton of crustaceans using hot concentrated alkaline solutions. It has been produced by deacetylation of Chitin is crab, shrimp, and blowfish. Calcium carbonate is the only other major component present in the shells of crustaceans such as lobsters and lobsters. The residual chitin can then be easily isolated from the microorganism by treatment with dilute mineral acids. Deacetylation can be achieved with concentrated alkaline solutions, usually at the boiling point of the solution.

In the production of chemicals by fermentation, virtually all residues, including mycelial mats, are discarded. Disposed of as waste. Recently, it has become clear that such by-products Although the amount of variation depends on the species, and the amount can be compared with the amount obtained from crustacean shells, It has been recognized that it contains chin and may have industrial uses. however, The chitin in these by-products is bound to other polymeric substances, and from these substances Not easily separated.

GB2026516 includes Allomyces, Aspergillus, Mucor and Penicillium. Residues from fermentation methods involving certain filamentous fungi, such as crab shells, can be removed from traditional methods using crab shells. In a similar manner, the chitin present is deacetylated by treatment with a hot concentrated alkaline solution. The chitosan produced in this way can be fermented using the same fungi-related fermentation method. can be complexed with glucan found as a residue for direct final use without post-treatment. It is possible to develop a product that has properties similar to chitosan alone, and more importantly, in its applications. It describes how to bring it about.

However, the applicant has determined that whether the source of chitin is crustacean shells or biomass, by forming a slurry of with an organic diluent prior to treatment with a strong alkaline solution. The amount of alkali required is much lower than previously used, and , an efficient solution that alleviates strong alkaline solution recovery or disposal problems associated with prior methods. It has been found that a method for deacetylating chitin can be obtained. Please use diluent after using it Therefore, it can be easily separated by methods known to those skilled in the art.

Generally, dilution methods are preferred and the recovered diluent is recycled to the process.

Accordingly, the present invention provides a slurry of chitin source that is essentially inert and water-miscible under the reaction conditions. The slurry is formed with an organic diluent and the slurry is heated to an alkali to chitin source weight ratio of 0. ．． 75:1-3.0=1 aqueous alkaline solution and the reaction product chitosa Provides a method for producing chitosan from chitin, comprising separating chitin from a liquid medium. Ru.

Preferably, the organic diluent is an alcohol or ketone, but other water-miscible diluents may be used. Agents can also be used.

As in the case of the previous method, the chitin for treatment according to the invention can be prepared from crab, blown, rotten It can be economically derived from the shells of crustaceans such as blasters and shrimp.

First, the shell is treated with dilute mineral acid to remove calcium carbonate. Locustidae and Isoptera Although chitin sources such as insects are useful, they are not economical to process. According to the invention An important source of chitin that can be used in the process is a by-product of industrial fermentation processes. Kichi Similar to minerals, biomass also contains variable amounts of other components such as other polysaccharides, pigments, proteins, etc. Contains substances and lipids.

Partial separation of chitin from other components found in biomass can be achieved by dilute alkaline solutions. Pre-treatment with It can be carried out on a regular basis. Usually in about 2.5% W/V sodium hydroxide solution. Pre-treatment is sufficient. Following deacetylation of chitin, residual insoluble polysaccharides are present. Chitosan, if any, is dissolved in a dilute organic acid such as 0.5% acetic acid. It can be separated from the product chitosan by.

Any chitosan product of the invention is soluble in dilute organic acids, suitably at least 60% deacetylated, and this degree of deacetylation can be influenced by water treatment, metal adsorption and other reactions. It represents commercially available chitosan used for

The alkaline solution must be strong enough to effect the desired deacetylation of chitin. Should. Aluminum containing at least 38% sodium hydroxide, especially from 38 to 40% Potash solution is preferred. Because this has the added benefit of storage stability. It is et al. The required amount of alkaline solution relative to the amount of chitin source is preferably on a weight basis. The ratio is 1:1 or less. Although larger amounts of alkali may be present, such amounts are There are no significant benefits of mixing it into the body.

When the organic diluent is present, sufficient organic diluent is present to ensure efficient stirring of the reaction mixture. In some cases, smaller amounts of alkali can be used. Generally, 0.75-3.0: A range of alkaline solution to chitin source weight ratios is used. This is up to about 10=1 Comparable to conventional methods which require a weight ratio of alkaline solution to chitin source of .

According to the practices of the present invention, the water-miscible organic diluent is more mobile than the chitin source. Present in sufficient amount to form a slurry. Generally, for 1 part by weight of chitin source A small amount of diluent (4 parts by weight to 20 parts by weight or less) is required.

Organic substances having a boiling point in the range 40°C to 120°C are preferred as diluents. Typical In this case, the substance is selected from alcohols and ketones, but as a general rule, the reaction conditions are A water-miscible organic diluent that is essentially inert and has a boiling point within a preferred range. You can use any of them if you have them.

The diluent acts as a distribution medium for the alkali and is preferably miscible with the alkali. Not. However, a small amount of alkali dissolved in the diluent can be tolerated and when it is advantageous to ensure uniform alkali distribution throughout the solid material. Even.

Molds, yeasts or fungi, which are the residues of fermentation processes, are treated with organic solvents after extraction of the desired product. The residue advantageously forms the slurry required for the process of the invention. It is then diluted with an appropriate amount of the same solvent to achieve the desired results.

When using organic diluents with relatively low boiling points, it is not essential, but higher Preferably, the reaction is carried out under pressure to allow the use of temperatures. in general, The higher the temperature, the shorter the reaction time required.

To eliminate chitin degradation within the reaction vessel, carry out the process in an inert atmosphere It is preferable. Otherwise, the molecular weight of the product obtained may be undesirably reduced. .

Generally, for industrial applications, around 1 x 105 to 2 x 10' depending on the intended use. average molecular weight is required.

As a diluent, use an alcohol such as Impropatool, which refluxes at a higher temperature than acetone. The slurry containing the slurry can be carried out without the use of a pressure vessel. but However, such diluents generally form azeotropes containing about 12-20% water. Because of this, they are not very easily recovered for later use.

The invention is further illustrated by the following examples, in which all parts are by weight.

Den--1 A fine chitin (1 part) sample prepared from blown shells was mixed with t-butanol (15 parts). slurry in a solution containing sodium hydroxide solution in an amount varying from 0.75 to 1.5 parts. solution (50% w/v) was added. The mixture was stirred at room temperature for 15 minutes, then 7 Heated at 5°C for 3 hours. The product is filtered, washed to remove residual alkali, and and dried.

All products were found to be soluble in 1% aqueous acetic acid.

5 - once Four chitin (1 part) samples prepared as in Example 1 were dissolved in isopropanol (16 parts). to slurry and add varying concentrations of sodium hydroxide solution (1.5 parts). Mixed The mixture was stirred at room temperature for 15 minutes and then heated at 80"C for 3 hours. The product was filtered. , washed until free of residual alkali, and dried. The product will be Three are soluble in a 1% acetic acid aqueous solution, and two have the following properties. 021 (21) 2 40 43 0, 385 (385) 3 45 39 0.090 (90) 4 50 34 0.064 (64) This comparative example - raw insoluble product.

Example-1].

Chitin prepared from blown shells (1 part) was slurried in Improper Tool (16 parts). A 5% W/W sodium hydroxide solution (1.5 parts) was added. Mixed The mixture was stirred at room temperature for 15 minutes and then heated at 80° C. for 4 hours.

The product was filtered, washed to remove residual alkali, and dried.

The product is soluble in 1% aqueous acetic acid (0.24% insoluble); The liquid had a viscosity of 0.037 Pa (37 cps). Analysis revealed that the product was was shown to have 32.5% residual amide groups.

9-1 Chitin prepared from shrimp shells (1 part) was slurried in isopropanol (16 parts). 50% W/W sodium hydroxide (1.5 parts) was added. at room temperature After stirring for 15 minutes, the mixture was heated to reflux at its boiling point (approximately 83° C.) for 3 hours. Living The product was filtered, washed neutral and dried.

The product is soluble in a 1% aqueous acetic acid solution, and a 1% solution in this solvent has a pressure of 0.28 Pa ( It had a viscosity of 280 cps). Analysis revealed that the product contained 31% residual amide. group and a molecular weight of 1.2X10'.

9-1 Chitin prepared from blown shells (1 part) was mixed with isopropanol (16 parts) as in Example 4. ) and add 50% w/w sodium hydroxide (1.5 parts). Ta. The mixture was refluxed as described in Example 4 except for a nitrogen atmosphere. Filter the product Filtered, washed neutral and dried.

The product is soluble in a 1% acetic acid aqueous solution, and a 1% solution in this solvent has a pressure of 0.44 Pa ( When analyzed, the product had a viscosity of 31% residual amide (440 cps). group and a molecular weight of 1.2XIO'.

L-ball Chitin prepared from blown shells (1 part) was slurried in acetone (16 parts). , 50% w/w sodium hydroxide (1.5 parts) was added. 15 minutes at room temperature After stirring, the mixture was heated at 56° C. for 5 hours. Filter the product until neutral. and dried.

Analysis showed that the product had 37.5% residual amide metal and was dissolved in 1% acetic acid in water. The liquid had a viscosity of 0.137 Pa (137 cps).

Nine-two Fungal mycelium (1 part) was slurried in acetone (10 parts) and 40% W/ W sodium hydroxide (1 part) was added. The mixture was heated at 83°C for 6 hours.

The product was filtered, washed free of residual alkali, and dried.

The product contained 72% chitosan extracted with 0.5% aqueous acetic acid. extracted The obtained chitosan had a molecular weight of 2.73×10@.

9-1 Dried fungal mycelium (1 part) was lined with polytetrafluoroethylene. Slurry in acetone (8 parts) in an autoclave with a working volume of 10 liters. did. Add 40% sodium hydroxide (1 part) and bring the mixture to 0.165MP The mixture was heated at 85° C. for 1 hour with constant stirring under a pressure of 24 psi. solid The product was removed, washed, neutralized and then dried.

The extractable chitosan has a residual amide content of 24.6% and a molecular weight of 5X10'. did.

Nine-Yu Fungal mycelium (1 part) was slurried in acetone (10 parts) and 40% hydroxylated. Sodium solution (1 part) was added. After stirring for 15 minutes at room temperature, the mixture was The mixture was heated under pressure at 85° C. for 3 hours. The recovered solid product is washed until neutral and then and dried.

The product contained 60% chitosan extractable with 0.5% aqueous acetic acid. extracted The chitosan obtained had a residual amide content of 23% and a molecular weight of 2.13X10'. .

Kugami Yu Dried fungal mycelium (1 part) was mixed with acetone (16 parts) and 40% aqueous sodium hydroxide. Slurried in a mixture with aluminum (2.8 parts). the whole thing in an autoclave The mixture was heated for 3 hours with stirring. Temperature: 100″C1, pressure: 3 bar It became Lugege. Remove solid product, wash, neutralize, rewash and dry did.

When this product was treated with 0.5% aqueous acetic acid, the chitosan dissolved. this After separation from the residual solids, it was reprecipitated with alkali, washed and dried. chitosan was found to have an average molecular weight of 1,1X10' and a residual amide content of 36%. .

international search report 1″’--”’”-”-” PCT/GB 89101274SA 3211 2

Claims (9)

[Claims] 1. The chitin source slurry is essentially inert under chitin and alkali reaction conditions. The slurry is formed with a water-miscible organic diluent, and the slurry is heated to an alkali to Treated with an aqueous alkaline solution with a weight ratio of 0.75:1 to 3.0:1 and reacted. Chitosan production from chitin, including separating the product chitosan from a liquid medium Method. 2. The method according to claim 1, wherein the organic diluent is an aliphatic alcohol or a ketone. . 3. 3. The organic diluent according to claim 1 or 2, wherein the organic diluent has a boiling point of 40°C to 120°C. Method. 4. 4. A method according to claim 1, 2 or 3, wherein the source of chitin is derived from crustacean shells. . 5. 4. The method according to claim 1, 2 or 3, wherein the chitin source is a by-product of an industrial fermentation process. Law. 6. Claim wherein the alkaline aqueous solution is a 38-40% by weight sodium hydroxide solution. 6. The method according to any one of 1 to 5. 7. Any of claims 1 to 6, wherein the diluent to chitin source weight ratio is between 4/1 and 20/1. The method described in paragraph (1). 8. 8. According to any one of claims 1 to 7, the alkaline treatment is carried out under overpressure. Method. 9. Claims 1 to 8, wherein the alkali treatment is carried out under an inert (non-oxidizing) atmosphere. The method described in any one of the above.