RU2615636C1 - Chitosan production method - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: chitosan production method is proposed, comprising grinding of insect puparia, alkaline treatment of chitin-containing raw materials with constant strirring at elevated temperature and further washing of the remainder with distilled water. Musca domestica puparia are used. Alkaline treatment is carried out at a temperature of 80°C with 1-1.5% alkali. Two-stage treatment is additionally performed with 3.5-5% hydrochloric acid and 4.5-5% sodium hydroxide while stirring for 1.5-2 hours at each stage, followed by filtration and washing of dry extract obtained after each processing stage with distilled water. Puparia are pre-washed with water from foreign substances before grinding.

EFFECT: increased finished product output.

2 tbl, 3 ex

Description

The invention relates to biotechnology and can be used in medicine, veterinary medicine, agriculture, cosmetic and food industries.

Most of the methods for producing chitosan are associated with the isolation of this polysaccharide from crustacean shells (crab, shrimp, krill, gammarus, etc.).

A known method of producing chitosan from crustaceans with a 50% sodium hydroxide solution, followed by exposure for 5-20 days at room temperature with periodic stirring (Patent, RU No. 21116733, published on 08/10/1998).

A known method of producing chitosan from the carapace of king crab, (Patent, RU No. 2087483, published 08/20/1997), in which chitosan is obtained by grinding natural chitin-containing raw materials, decalcification with 1-5% hydrochloric acid solution and deproteinization with 1-5% hydroxide solution sodium, as well as washing and deacetylation of 46-47% sodium hydroxide solution. Moreover, chitin-containing raw materials are crushed to obtain at least 90% of the particles of the fraction (+5) - (- 0.5). Then, before washing, three cycles of alternating stages of deproteinization and decalcification are carried out. Each subsequent cycle of alternating stages is carried out at a higher temperature than the previous one.

However, these technologies are characterized by the use of a limited volume of a natural source - crustacean chitin, significant alkaline costs and time costs.

There is a method of producing chitosan from shells of shrimp, which is characterized by a rather stringent temperature regime during deacetylation (from 90 ° C to 110 ° C for 1-3 hours), which negatively affects the quality of the finished product (Patent, RU 2548178, published on 20.04. 2015).

Closest to the claimed method for producing chitosan is a method (Patent RU No. 2067588, published 10.10. 1996), in which the chitin of the cuticular membranes of insects is crushed to particles of 0.2-0.3 mm, treated with a 40% solution of caustic alkali at 100- 110 ° C, the liquid module 1:20 for 3-3.5 hours with simultaneous exposure to ultrasound with a frequency of 15-35 kHz.

The disadvantages include a high concentration of alkali in combination with high temperature conditions, which leads to rapid wear of equipment and, accordingly, to an increase in the cost of the product.

The technical task is to develop a cheap and quick way to get chitosan from the generally available chitin-containing raw materials.

The technical result consists in increasing the yield of the finished product, improving the chemical purity of the product, as well as simplifying the method of producing chitosan due to more rational technology and readily available raw materials.

The technical problem is solved, and the technical result is achieved by the fact that in the known method for producing chitosan, including alkaline treatment of chitin-containing raw materials, chopped Muscadomestica puparia at elevated temperature and further washing of the residue with distilled water, while alkaline treatment is carried out with 1-1.5% sodium hydroxide. Then a sequential treatment is carried out with 3.5-5% hydrochloric acid and 4.5-5% sodium hydroxide with mechanical stirring, and before grinding the pupars are pre-washed with water from foreign matter.

The method of producing chitosan consists of the following successive stages:

Stage 1

The pupal flies are washed with water until they are completely cleaned of the nutrient substrate, then dried at a temperature of 15-20 ° C.

2 stage

The resulting puparia are ground in a ball mill to particle sizes, for example, 0.2-0.3 mm.

3 stage

An alkali, for example 100 ml of a 1-1.5% sodium hydroxide solution, is added to 5 g of ground puparium, and stirred, for example, with a magnetic stirrer for 1.5-2 hours, then filtered.

4th stage

Inorganic acid, for example 3.5-5% Hcl, is added to the resulting dry residue in a volume of 100 ml and stirred, for example, with a magnetic stirrer for 1.5-2 hours, then filtered and washed with 500 ml of distilled water.

5 stage

An alkali, for example 100 ml of 4.5-5% NaOH, is added to the obtained dry residue, and stirred, for example, with a magnetic stirrer for 1.5-2 hours, then filtered and washed with 500 ml of distilled water,

6 stage

The resulting chitosan is dried in an oven at a temperature of 60 ° C. The yield of chitosan is 70-80%.

The color of the chitin samples depends on the feedstock; the color ranges from light yellow to light brown. The obtained chitosan is a white powder with a degree of deacetylation of 88-95%, a protein content of less than 0.005% and a moisture content of less than 5%.

Example 1

5 g of chitin-containing raw materials from puparia, for example Musca domestica, crushed to a particle size of 0.2-0.3 mm, are treated with 100 ml of a 1% NaOH solution at 80 ° C for 1.5 hours. At the same time, the entire volume of the reaction mixture is stirred on a magnetic stirrer. Then the remaining product is washed with water (500 ml) to pH 7.0, 5% HCl in a volume of 100 ml is added to the obtained dry residue, stirred for 1.5 hours, then 100 ml of 5% NaOH is added and stirred for 1.5 hours, then filtered and washed with 500 ml of distilled water, dried. The weight of the dried precipitate is 3.55 g, white with a degree of deacetylation of 89%, a protein content of less than 0.005% and a moisture content of less than 5%.

Example 2

5 g of chitin-containing raw materials from Musca domestica puparia, crushed to a particle size of 0.2-0.3 mm, are treated with 100 ml of a 1.5% NaOH solution at 80 ° C for 1.5 hours. At the same time, the entire volume of the reaction mixture is stirred on a magnetic stirrer. Then the remaining product is washed with water (500 ml) to a pH of 7.0, 3.5% HCl in a volume of 100 ml is added to the obtained dry residue, stirred for 1.5 hours, then 100 ml of 4.5% NaOH are added and stirred in for 1.5 hours, then filtered and washed with 500 ml of distilled water, dried. The weight of the dried precipitate is 4.03 g, white with a degree of deacetylation of 88%, a protein content of less than 0.005% and a moisture content of less than 5%.

Example 3

5 g of chitin-containing raw material from Musca domestica puparia, crushed to a particle size of 0.2-0.3 mm, are treated with 100 ml of a 1.25% NaOH solution at 80 ° C for 1.5 hours. At the same time, the entire volume of the reaction mixture is stirred on a magnetic stirrer. Then the remaining product is washed with water (500 ml) to a pH of 7.0, 4.75% HCl in a volume of 100 ml is added to the resulting dry residue and stirred for 1.5 hours, then 100 ml of 4.75% NaOH are added and stirred in for 1.5 hours, then filtered and washed with 500 ml of distilled water, dried. The weight of the dried precipitate 3.80 g, white with a degree of deacetylation of 95%, protein content less than 0.005% and humidity less than 5%.

Chitosan is characterized, according to TU 2321-005-63732773-2012, with the following parameters: appearance, color, mass fractions of water, residue after calcination of insoluble substances and the degree of deacetylation, which are shown in table 1.

The table shows that chitosan produced by the claimed method meets the characteristics of TU. Table 2 shows the comparative characteristics of chitosan obtained from insect puparia.

The examples in table 2 indicate that the claimed method of producing chitosan from insect puparia allows with a similar quantitative yield of the product to improve its quality while reducing the time and reagents spent on the production unit. The claimed method allows us to talk about the improvement and expansion of the technology for producing chitosan.

Claims (1)

A method of producing chitosan, including grinding insect puparia, alkaline treatment of chitin-containing raw materials with constant stirring at elevated temperature and further washing of the residue with distilled water, characterized in that Musca domestica puparia are used, and alkaline treatment is carried out at a temperature of 80 ° C 1-1.5% alkali, in addition, a two-stage treatment with 3.5-5% hydrochloric acid and 4.5-5% sodium hydroxide is carried out with stirring for 1.5-2 hours for each stage, followed by filtration and The flushing with distilled water obtained after each stage of treatment of the dry residue, which is prewashed with water from extraneous inclusions before grinding pupae.