JP2758796B2 - Polysaccharide extraction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysaccharide extraction method, and more particularly, to a polysaccharide extraction method capable of efficiently removing pigments contained in cells of microalgae to extract a light-colored polysaccharide. About.

[0002]

2. Description of the Related Art Conventionally, as a method for extracting polysaccharides from microalgae, a method using a strong acid or a strong alkali has been known (Japanese Patent Application Laid-Open No. 58-201993). There was a problem that some of the molecules were reduced in molecular weight due to hydrolysis with alkali. As a method for solving the above-mentioned problem, the present applicant has disclosed in Japanese Patent Application Laid-Open Nos. 4-158794 and 4-222593 that a cell of a wet alga body separated from an algal culture solution is destroyed and then a protease and / or Alternatively, a method for extracting polysaccharides by performing an enzymatic reaction with fatty acid esterase was proposed. According to this method, a low molecular weight of the polysaccharide can be prevented because a strong acid or a strong alkali is not used. However, since a large amount of alcohol is required to recover the polysaccharide, the cost cannot be reduced, and the wet alga cannot be reduced. There was a drawback that light-colored polysaccharides could not be obtained because pigments contained in the body could not be removed.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a polysaccharide extraction method capable of extracting a light-colored polysaccharide at low cost.

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for extracting polysaccharides by enzymatic reaction after destroying cells of a wet algal body separated from an algal culture solution. The present invention relates to a method for extracting a polysaccharide, which comprises subjecting cells to destruction by adding an organic solvent, removing fat-soluble components in the cells, and then performing an enzymatic reaction.

[0005]

The pigment group and the polysaccharide in the microalgal cells are present independently, the pigment group is present in the photosynthetic tissue, and the polysaccharide is present in the starch granules or extracellularly. When algal cells are destroyed in an aqueous solution, the polysaccharide exists in a state where the molecules are spread, and the pigment is entangled in this polysaccharide and some kind of bond is generated between the polysaccharide and the pigment, so that in the subsequent processing, It is difficult to separate the dye. Microalgae pigments include fat-soluble pigments such as chlorophyll and water-soluble pigments such as phycoerythrin.In the present invention, cell destruction is performed not in an aqueous solvent but in a water-miscible solvent to remove polysaccharides. While condensed in a water-miscible solvent, the intracellular fat-soluble dye can be dissolved in the solvent and removed, thereby preventing the deposition of the dye on the polysaccharide in the subsequent treatment.

[0006] The microalgae used in the present invention are not particularly limited.
, Fresh water) are preferable because they contain a large amount of polysaccharides. These microalgae are used after being cultured by a known method. Extraction of the polysaccharide from the algal culture is performed, for example, as follows.

First, an algal culture is separated into a supernatant and a wet algal body by a solid-liquid separation operation such as centrifugation or filtration. A water-miscible solvent is added to the obtained wet algal cells, and cell destruction is performed using a homogenizer, a ball mill, or the like. The method of cell destruction is appropriately selected depending on the state of the wet algal body. As the water-miscible solvent, alcohols such as ethanol and isopropanol are used. The obtained cell disruption solution is separated into a precipitate containing a polysaccharide and a supernatant by a solid-liquid separation operation such as centrifugation or filtration, and water is added to the precipitate.
Stir at a temperature of 00 ° C. An enzyme is added to this aqueous solution to perform an enzyme reaction.

[0008] Enzymes used in the enzymatic reaction include proteolytic enzymes and fatty acid ester degrading enzymes. Examples of the protease include papain and various proteases, which are mixed enzyme agents of neutral or weakly alkaline endo- or exo-type proteases, and fatty acid esterases include α- or β-position fatty acids. A lipase that degrades, for example, pacreatin, is used. These enzymes may be used alone or in combination. The amount of the enzyme added is usually 10,000 to 500,
000 U (unit), and usually 7,500 to 30,000 U for fatty acid ester degrading enzyme. The enzymatic reaction is usually performed at a temperature of 30 to 80 ° C., preferably 40 to 60 ° C. for about 30 minutes to 24 hours while stirring or shaking. After completion of the reaction, 1/2 to 2 volumes of a water-miscible solvent is added to precipitate a suspended matter, which is collected by filtration or the like, and after sufficiently removing the solvent, dried and pulverized to obtain a purified polysaccharide.

According to the method of the present invention, since fat-soluble dyes and lipids can be removed by dissolving them in a water-miscible solvent, a light-colored polysaccharide can be extracted, and washing for decolorization can be performed. And the like are easy, so that the amount of solvent used can be reduced. This polysaccharide has a high viscosity, has an effect of reducing fluid frictional resistance, and can be used as a thickener, a dispersion suspension stabilizer, an emulsifier, and the like.

[0010]

The present invention will be described below with reference to examples. Example 1 An artificial seawater medium was used as a culture medium of microalgae (Polyphyllium kruentum), and culturing was performed by irradiating light of 5 to 10 Klx using a halogen lamp as a light source to obtain an algal culture solution. This algal culture solution was separated into a supernatant and a wet algal body by centrifugation, and 150 g of the wet algal body (solid content 13% by weight)
And add 600 ml of ethanol to the
Homogenized at rpm for 2 minutes. Thereafter, solid-liquid separation was performed by suction filtration, and 100 ml of ethanol was added to the precipitate, followed by homogenization at 10,000 rpm for 2 minutes. The solid was separated again by suction filtration, and the precipitate was recovered. The precipitate was washed with ethanol 2 to 5 times. Distilled water was added to the ethanol-insoluble fraction to make a 2% by weight solution, and the mixture was heated and stirred at 90 ° C. until it was sufficiently dissolved. Distilled water was added to this aqueous solution to cool it to 1% by weight, and 7.5 g of a protease (Protease A, manufactured by Amano Pharmaceutical Co., Ltd.) was added.
The mixture was stirred overnight to perform an enzyme reaction. After completion of the reaction, 2/3 volume of ethanol was added to precipitate and recover the polysaccharide suspension,
After washing with ethanol and removing the solvent sufficiently, 40 ° C
And vacuum dried. The obtained polysaccharide was pulverized into a product. The color of this product was light red and white. The total alcohol consumption was 7,200 ml.

Comparative Example 1 To 150 g (13% by weight solids) of wet algal cells obtained by the same operation as in Example 1, 300 ml of distilled water was added, and
After homogenizing at 0 rpm for 1 minute, the mixture was heated at 80 ° C. for 20 minutes. Then cool to room temperature and adjust to pH 8,
7.5 g of proteolytic enzyme (protease A) was charged, and the mixture was stirred at 50 ° C. overnight to perform an enzymatic reaction. After the completion of the reaction, an equal amount of ethanol is added to recover the polysaccharide by floating, and the polysaccharide is washed with ethanol to sufficiently decolorize. Thereafter, the solvent is sufficiently removed, followed by vacuum drying at 40 ° C. and pulverization. The product. The color of the obtained product was greenish brown.
The total amount of alcohol used was 10,000 ml.

[0012]

According to the method of the present invention, fat-soluble dyes such as chlorophyll can be removed in advance.
Coloring of the extracted polysaccharide by the pigment can be prevented, a polysaccharide having high commercial value can be obtained, and the amount of the solvent used for washing or the like can be reduced, so that the cost can be reduced.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C12P 19/04 CA (STN)

Claims (1)

(57) [Claims] 1. A method for extracting polysaccharides by destroying cells of a wet alga body separated from an algal culture solution and then performing an enzymatic reaction, wherein the cells are destroyed by adding a water-miscible organic solvent to the wet alga body. The present invention also relates to a method for extracting polysaccharides, which comprises performing an enzymatic reaction after removing fat-soluble components in cells.