JPH06141878A - Method for extracting polysaccharides - Google Patents

Abstract

PURPOSE:To provide a method for extracting polysaccharides in which the polysaccharides contained not only in a wet algal body but also in a culture solution can be extracted at a low cost according to simple operation without causing the pigmentation. CONSTITUTION:This method for extracting polysaccharides is characterized by allowing a culture solution of an alga in a sterile state to stand until a pigment in the culture solution fades while irradiating the culture solution with light and then extracting the polysaccharides in extracting the polysaccharides from the culture solution of the alga. Thereby, the light-colored polysaccharides can be obtained according to simple operation. The washing operation for the purpose of removing pigments after recovering the polysaccharides is not required. The operation can be simplified and the amount of the washing solvent can be reduced. Furthermore, since the polysaccharides contained not only in the wet algal body but also in the culture solution can be extracted, the recovery ratio of the polysaccharides can be improved to reduce the cost.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for extracting polysaccharides,
More specifically, the present invention relates to a polysaccharide extraction method capable of recovering a light-colored polysaccharide from an algae culture solution by a simple operation.

[0002]

2. Description of the Related Art Conventionally, a method of using a strong acid or a strong alkali is known as a method for extracting a polysaccharide from a microalgae (Japanese Patent Laid-Open No. 58-201993). There has been a problem that a part of the molecule becomes low molecular weight due to hydrolysis by alkali. As a method for solving the above-mentioned problems, the present applicant discloses in Japanese Patent Laid-Open No. 4-158794 and Japanese Patent Laid-Open No. 4-222593 that proteolytic enzymes and / Alternatively, we proposed a method for extracting polysaccharides that performs an enzymatic reaction with a fatty acid ester-degrading enzyme. According to this method, it is possible to prevent the lowering of the molecular weight of the polysaccharide because it does not use strong acid or strong alkali, but it is not possible to reduce the cost because a large amount of alcohol is required to recover the polysaccharide, and wet algae Since the pigment contained in the body cannot be removed, there is a drawback that a light-colored polysaccharide cannot be obtained. Moreover, the polysaccharide is contained not only in the wet algal cells, but also in the culture solution,
Since the recovery rate of the polysaccharide contained in the culture solution is low and the cost is high, the culture solution is currently discarded.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the prior art and to carry out a simple operation without pigmenting not only the wet algal cells but also the polysaccharides contained in the culture solution. It is to provide a method for extracting a polysaccharide that can be extracted at low cost.

[0004]

Means for Solving the Problems The present invention is, when extracting a polysaccharide from an alga culture solution, after leaving the alga culture solution in a sterile state while irradiating with light until the pigment of the culture solution fades, It relates to a method for extracting a polysaccharide, which is characterized by extracting a polysaccharide. In the present invention, since the polysaccharide is extracted after fading the pigment contained in the microalgae of the algae culture solution, there is no deposition of the pigment on the polysaccharide in the polysaccharide extraction and purification process, and therefore the extraction is performed. It is possible to simplify the purification operation. Further, not only the wet algal cells in the alga culture solution but also the polysaccharide contained in the culture solution can be recovered at low cost, so that the recovery rate of the polysaccharide is improved.

There are no particular restrictions on the microalgae used in the present invention.
, Freshwater) and the like, which contain a large amount of polysaccharides, are preferred. These microalgae are cultured and used by a known method. The cells of the microalgae contain a large amount of polysaccharides, but the cells themselves are not covered with the cell wall but covered with extracellular polysaccharides, and the polysaccharides are also dissolved and present in the culture medium.
The algae culture solution used in the present invention is previously irradiated with light,
It is left aseptic. Light having a wavelength ranging from the ultraviolet region to the visible region such as sunlight is used for light irradiation. The standing temperature is usually room temperature, but is not particularly limited. The algae culture solution is allowed to stand still or shaken until the pigment of the culture solution fades, specifically, until the culture solution becomes a milky white semi-gel, gel or dry solid. Usually, the leaving period is about 2 weeks to 1 month.

The method for extracting the polysaccharide from the milky white semi-gelled or dried solid culture is not particularly limited, but from the viewpoint of obtaining a high molecular weight polysaccharide, it is extracted as follows. Is preferred. First, distilled water is added to the culture to sufficiently dissolve the polysaccharide in the culture, and then homogenized or heated to form a uniform suspension, and this suspension is subjected to protein degrading enzyme, fatty acid ester degrading enzyme, etc. The enzyme is added and stirred for 4 hours to overnight to cause an enzymatic reaction to decompose the protein component. Examples of proteolytic enzymes include papain and various proteases, which are mixed enzyme agents of neutral or weakly alkaline endo- or exo-type proteases, and fatty acid ester-degrading enzymes include α- or β-position fatty acids. A lipase that decomposes, such as pacreatin, is used. These enzymes may be used alone or in combination. The amount of enzyme added is usually 10 for proteolytic enzyme per 100 ml of algae culture solution,
000 to 50,000 U (unit), and the fatty acid ester degrading enzyme usually has 7,500 to 30,000 U. The enzymatic reaction is usually 30 to 80 ° C., preferably 40
Stir or shake at a temperature of -60 ° C.

After completion of the enzymatic reaction, a water-miscible organic solvent such as 2/3 to 1 volume of alcohol is added to suspend and collect the polysaccharide, and the solvent is sufficiently removed, followed by drying at 40 ° C.
It can be ground to give a polysaccharide product. According to such an extraction method, the solid-liquid separation operation is insoluble, and the washing operation of the recovered polysaccharide with alcohol or the like can be omitted, so that the extraction and purification steps can be simplified and the amount of alcohol used can be reduced. Can be planned. This polysaccharide is highly viscous and has the effect of reducing fluid friction resistance.
It can be used as a thickener, a dispersion suspension stabilizer, an emulsifier and the like.

[0008]

EXAMPLES The present invention will be described below with reference to examples. Example 1 Artificial seawater (ASW) was used as a culture medium of microalgae (Polyphyridium kruentum), and a halogen lamp was used as a light source. Irradiation of 2 klx light was performed at 20 ° C. for about 2 weeks,
Cultivation was carried out while aerating air containing 5% CO ₂ to obtain an alga culture solution. 1 liter of the obtained culture solution was transferred to a flask with a cotton stopper, which had been sterilized by an autoclave in advance. A flask containing this culture solution was put into a germicidal lamp (wavelength 253.7n
m, output 2.0 W), and allowed to stand under irradiation and stored at 25 ° C. for 1 month. The culture solution in the flask changed from pinkish white to milky white gel.

Distilled water (360 ml) was added to this flask and stirred to obtain a suspension in which the polysaccharide was dissolved at a concentration of 2% by weight. This suspension was homogenized at 10,000 rpm for 1 minute to obtain a uniform suspension, and 3 g of protease A (manufactured by Amano Pharmaceutical Co., Ltd.), which is a proteolytic enzyme, was added thereto, and the mixture was stirred at 50 ° C. for 6 hours to remove protein. Decomposed the ingredients.
After completion of the reaction, ethanol was added in an equal amount, and the polysaccharide was suspended and collected by filtration. The solvent was sufficiently removed, vacuum dried at 40 ° C., and pulverized to obtain a polysaccharide product. The product was pale yellowish white.

Comparative Example 1 10 g of wet alga bodies from an alga culture solution obtained in the same manner as in Example 1
(Solid content 13% by weight) is separated by solid-liquid separation operation, and 800 ml of distilled water is added to the obtained wet alga body to obtain 10,000.
Homogenized at rpm for 1 minute and then heated at 80 ° C. for 20 minutes. The solution was cooled to room temperature and 1N-NaOH
Adjust the pH to 8 with and add 3g of Protease A to 50
The enzyme reaction was carried out by stirring for 6 hours at ° C. After the reaction was completed, an equal amount of ethanol was added to collect the polysaccharide,
It was washed 5 times to decolorize it sufficiently. Then, the solvent was sufficiently removed, and the product was vacuum dried at 40 ° C. to obtain a product. The resulting polysaccharide product was greenish brown.

[0011]

EFFECTS OF THE INVENTION According to the method of the present invention, a pigment that has been difficult to remove by depositing on a polysaccharide can be faded before extraction of the polysaccharide, so that a light-colored polysaccharide can be easily removed. It can be obtained by simple operation. In addition, the washing operation for the purpose of removing the dye after the recovery of the polysaccharide is insoluble, so that the operation can be simplified and the amount of the washing solvent used can be reduced. Further, not only the wet algal cells but also the polysaccharide contained in the culture solution can be extracted, so that the recovery rate of the polysaccharide is improved and the cost can be reduced.

Claims (1)

[Claims] 1. When extracting a polysaccharide from an algae culture solution, the algae culture solution is irradiated with light in a sterile state and allowed to stand until the pigment of the culture solution fades, and then the polysaccharide is extracted. Extraction method of polysaccharides.