JPH08275793A - Production of useful polymer using microalgae, production of paper and biodegradable plastic using the same - Google Patents

Abstract

PURPOSE: To obtain useful macromolecules such as a feedstock of pulp or a biodegradable plastic by crushing the cells of microalgae cultured in the carbon dioxide fixation, extracting them with an organic solvent and centrifuging the extract to collect the substance in the organic phase. CONSTITUTION: The cells of microalgae are crushed, the crushed cells are mixed with an organic solvent to extract the soluble components and the mixture is centrifuged to separate into the organic solvent phase and the residue. Then, the residue is combined with water or a neutral buffer solution to extract the water-soluble components and the mixture is centrifuged to separate into the aqueous solution phase and the residue. Further, the residue is treated with an aqueous alkali to separate into the alkali-soluble aqueous phase and the residue. The alkali-soluble phase is acidified lower than pH7, centrifuged to separate into the precipitate and the supernatant and the objective useful macromolecules which can be utilized as a pulp feedstock or a biodegradable plastic are obtained from the supernatant and the precipitate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a useful polymer using microalgae, which comprises C using photosynthetic microalgae.
The present invention relates to a technique for producing a useful polymer that can be used as a raw material for pulp that can be used for papermaking, a biodegradable plastic, etc., from surplus microalgae obtained in an O ₂ -immobilization plant.

[0002]

2. Description of the Related Art Conventionally, a large amount of photosynthetic organisms such as chlorella and spirulina are cultivated, and useful substances such as sugars, fermentation substrates, proteins, unsaturated fatty acids and pigments are produced from the cultivated photosynthetic organisms, or photosynthetic organisms are used. Wastewater treatment was performed. In addition, as the problem of global warming due to a large amount of carbon dioxide (CO ₂ ) emission is highlighted, research and development of an exhaust gas treatment technology for absorbing and assimilating CO ₂ in exhaust gas by photosynthetic organisms is underway. Furthermore, as a result of the search for photosynthetic organisms suitable for use in such a CO ₂ -immobilized plant, green algae, brown algae,
It has been proposed that photosynthetic microalgae such as diatoms and cyanobacteria are extremely effective.

On the other hand, from another viewpoint of preserving the global environment, it is necessary to suppress waste of forest resources and fossil fuels as much as possible, and pulp and plastic raw materials that are currently consumed in large quantities. Alternative resources are needed.

[0004]

Conventionally, the pulp raw material is
Due to the use of wood with high fiber content, its large consumption leads to a decrease in forest resources, and for the conservation of forest resources,
There is an urgent need for the development of alternative raw materials. In addition, plastics are mass-produced from petroleum resources. This plastic has various problems in waste disposal. That is, since plastic trash generates harmful gas when incinerated and remains without being decomposed even if it is discarded at a landfill site, there will be a chronic shortage of landfill sites as long as large consumption continues. Recently, biodegradable plastics that can be decomposed by microorganisms have been attracting attention in consideration of this plastic waste problem, and various studies have been conducted to realize them, but no suitable material has been found. .

The present invention has been made in view of the above circumstances, and a useful polymer that can be used as a raw material for pulp, biodegradable plastics, etc., which can be used in papermaking, etc., can be obtained in a CO ₂ -immobilized plant. It is intended to provide a method for producing a useful polymer that can be obtained from microalgae.

[0006]

The first method of the method for producing a useful polymer using microalgae according to the present invention is to crush cells of microalgae, add an organic solvent to the crushed cells, and add the organic solvent. It is characterized in that a component soluble in a solvent is extracted, and then the mixture is centrifuged to separate an organic solvent phase and a residue to obtain a useful polymer contained in the organic solvent phase.

The second method of the method for producing a useful polymer using microalgae according to the present invention is to disrupt cells of microalgae,
An organic solvent is added to the disrupted cells to extract a component soluble in the organic solvent, the mixture is then centrifuged to separate an organic solvent phase and a residue, and the residue is then mixed with water or a neutral buffer solution. Is added to extract a water-soluble component, and then the mixture is centrifuged to separate an aqueous phase and a residue to obtain a useful polymer contained in the aqueous phase.

The third method of the method for producing a useful polymer using microalgae according to the present invention is to disrupt cells of microalgae,
An organic solvent is added to the disrupted cells to extract a component soluble in the organic solvent, the mixture is then centrifuged to separate an organic solvent phase and a residue, and the residue is then mixed with water or a neutral buffer solution. To extract a water-soluble component, and then centrifuging the mixture to separate an aqueous solution phase and a residue, and then adding an alkaline aqueous solution to the residue to extract an alkali-soluble component, and then centrifuging the alkaline aqueous solution. It is characterized in that a useful polymer contained in the residue is obtained by separating into a phase and a residue.

A fourth method of producing a useful polymer using microalgae according to the present invention is to crush cells of microalgae,
An organic solvent is added to the disrupted cells to extract a component soluble in the organic solvent, the mixture is then centrifuged to separate an organic solvent phase and a residue, and the residue is then mixed with water or a neutral buffer solution. To extract a water-soluble component, and then centrifuging the mixture to separate an aqueous solution phase and a residue, and then adding an alkaline aqueous solution to the residue to extract an alkali-soluble component, and then centrifuging the alkaline aqueous solution. Phase and residue separated, then acid is added to the alkaline aqueous phase to bring the pH to 7 or less,
Then, centrifugation is performed to separate the precipitate from the supernatant to obtain a useful polymer contained in the supernatant.

The fifth method of producing a useful polymer using microalgae according to the present invention is to crush cells of microalgae,
An organic solvent is added to the disrupted cells to extract a component soluble in the organic solvent, the mixture is then centrifuged to separate an organic solvent phase and a residue, and the residue is then mixed with water or a neutral buffer solution. To extract a water-soluble component, and then centrifuging the mixture to separate an aqueous solution phase and a residue, and then adding an alkaline aqueous solution to the residue to extract an alkali-soluble component, and then centrifuging the alkaline aqueous solution. Phase and residue separated, then acid is added to the alkaline aqueous phase to bring the pH to 7 or less,
Next, centrifugation is carried out to separate the precipitate from the supernatant, and then the precipitate is dialyzed and further dried to obtain a useful polymer.

The sixth method of producing a useful polymer using microalgae according to the present invention is to disrupt cells of microalgae,
An organic solvent is added to the disrupted cells to extract a component soluble in the organic solvent, the mixture is then centrifuged to separate an organic solvent phase and a residue, and the residue is then mixed with water or a neutral buffer solution. Is added to perform hot extraction, and then a proteolytic enzyme is added to decompose the protein. Then, the enzyme-treated product is centrifuged to separate a residue and a supernatant liquid, and then the supernatant liquid is concentrated, and This concentrate is dialyzed, alcohol is added, and then centrifugal separation is performed to separate a precipitate mainly composed of hot water-soluble polysaccharides from an alcohol phase, and a useful polymer is obtained from the precipitate. There is.

The sixth method of producing a useful polymer using microalgae according to the present invention is to disrupt cells of microalgae,
An organic solvent is added to the disrupted cells to extract a component soluble in the organic solvent, the mixture is then centrifuged to separate an organic solvent phase and a residue, and the residue is then mixed with water or a neutral buffer solution. Is added to perform hot extraction, and then a proteolytic enzyme is added to decompose the protein. Then, the enzyme-treated product is centrifuged to separate a residue and a supernatant liquid, and then the supernatant liquid is concentrated, and This concentrate is dialyzed, alcohol is added, and then centrifugal separation is performed to separate a precipitate mainly composed of hot water-soluble polysaccharides from an alcohol phase, and a useful polymer is obtained from the precipitate. There is.

The seventh method of producing a useful polymer using microalgae according to the present invention is to disrupt cells of microalgae,
An organic solvent is added to the disrupted cells to extract a component soluble in the organic solvent, the mixture is then centrifuged to separate an organic solvent phase and a residue, and the residue is then mixed with water or a neutral buffer solution. Is extracted by heating, and then centrifuged to separate a residue containing a useful polymer containing protein as a main component and a supernatant containing a hot water-soluble polysaccharide, and containing the protein as a main component from the residue. In addition to obtaining a useful polymer, a useful polymer containing a hot water-soluble polysaccharide as a main component is obtained from the supernatant.

The organic solvent used in the method for producing useful polymers using these microalgae is ethyl alcohol,
It is desirable that the solvent is one or more solvents selected from acetone and n-hexane. In addition, the microalgae used in these production methods may be one kind selected from the group consisting of cochlear algae, green algae, brown algae, diatoms, yellow-green algae, true eye spot algae, haptoalgae, red algae, and cyanobacteria. Furthermore, in these production methods, as a means for crushing the cells of the microalgae, an ultrahigh pressure pressing method, a breaking method using a high-speed rotary blade, or the like,
It may be one kind or two or more kinds selected from ultrasonic crushing method and enzymatic decomposition method. Further, in these production methods, the useful polymer is mainly composed of a protein having a molecular weight of 250,000 or more and its derivative or a hot water-soluble polysaccharide having a molecular weight of 250,000 or more and its derivative.

The papermaking method according to the present invention comprises a useful polymer obtained by either the microalgae itself or the above-mentioned method for producing a useful polymer, a separated residue or other fiber component, and a paste. The method is characterized in that a raw material pulp liquid is prepared, paper is made from this raw material pulp liquid, and then it is dried to produce paper.

The paste used in this papermaking method is preferably a water-soluble polymer fiber material such as carboxymethyl cellulose which can be easily biodegraded. Furthermore, in this papermaking method, a flocculant such as aluminum sulfate may be added to the raw material pulp liquid.

The method for producing a biodegradable plastic using the useful polymer according to the present invention is a useful polymer or microalgae itself obtained by any of the above-mentioned methods for producing a useful polymer, and a separated residue or With other fiber components,
Prepare a biodegradable plastic raw material liquid containing a coagulant,
This raw material liquid is put into a mold, solidified, and dried to produce a biodegradable plastic.

In the method for producing a biodegradable plastic using this useful polymer, a water-soluble polymer fiber substance such as carboxymethyl cellulose, which is easily biodegradable, is preferable as the coagulant.

[0019]

The method for producing a useful polymer using microalgae according to the present invention comprises using microalgae as a raw material, adding an organic solvent to the cells of the microalgae to disrupt the cells, and centrifuging the mixture. A useful polymer is obtained by separating an organic phase soluble in an organic solvent and an insoluble residue, and purifying the insoluble residue as it is or by adding various purification processes. This useful polymer is mainly composed of a protein having a molecular weight of 250,000 or more and a derivative thereof contained in microalgae or a hot water-soluble polysaccharide and a derivative thereof having a molecular weight of 250,000 or more. These useful polymers can be formed into a film-like polymer film by spreading an aqueous solution thinly and drying or heating, or by flowing into a mold of a desired shape and solidifying to obtain articles of various shapes. You can A material using this useful polymer is mainly composed of a protein having a molecular weight of 250,000 or more and its derivative or a hot water-soluble polysaccharide having a molecular weight of 250,000 or more and its derivative, and therefore soil microorganisms can be used even when discarded. It is quickly decomposed by

In this method for producing a useful polymer, the useful solvent finally obtained is obtained by using one or more highly safe solvents selected from ethyl alcohol, acetone and n-hexane as the organic solvent. Even if the polymer is eaten, the residual organic solvent does not adversely affect the human body, and the useful polymer is highly safe for the human body.

The papermaking method using the useful polymer according to the present invention prepares a raw material pulp liquid containing microalgae itself or the above useful polymer, a separated residue or other fiber component, and a paste, Since paper is produced by making paper from this raw pulp liquid and then drying it, paper can be produced without using wood pulp or by greatly reducing the amount of wood pulp used.

A method for producing a biodegradable plastic using a useful polymer according to the present invention is a biodegradation containing microalgae itself or the above useful polymer, a separated residue or other fiber component, and a coagulant. The biodegradable plastic is harmless and can be easily discarded by soil microorganisms even if it is discarded, because a raw material liquid for biodegradable plastic is prepared, put into a mold, solidified and dried to produce a plastic-like product. Therefore, it is possible to provide a plastic product that can be easily disposed of because it is decomposed into. Moreover, since the product contains proteins and polysaccharides as main components, it can be used as a fertilizer component and a soil conditioner as a result of being buried and decomposed by soil microorganisms.

[0023]

EXAMPLE FIG. 1 is a diagram showing a first example of a method for producing a useful polymer using microalgae according to the present invention. In this example, among the polymer components contained in the microalgae, Especially, the case suitable for the production of useful polymers mainly composed of proteins is shown. Microalgae used in the present invention, a single cell having a photosynthetic function with oxygen generation, like land animals,
Or, it is a multicellular alga close to a single cell and is a generic term for a small individual (1 to several tens of microns) of alga that has undifferentiated cells as an organ and needs to be identified under a microscope. It is characterized by containing a photosynthetic dye such as. As taxa, there are phytoplankton, green algae, brown algae, diatoms, yellow-green algae, true-eye spot algae, haptoalgae, red algae, cyanobacteria, etc., all of which have photosynthetic functions and are also called phytoplankton.

This microalga is widely present in nature and can be used as a raw material in the method of the present invention by culturing it in a large amount. In particular, in a CO ₂ fixation plant using microalgae, which is currently being researched, a large amount of microalgae can be obtained on average,
Microalgae obtained from this type of CO ₂ immobilization plant are suitable as a raw material for the method of the present invention.

In addition to water, microalgae are rich in useful components such as proteins, fibers, polysaccharides and lipids. Among these components, proteins, fiber components, polysaccharides, and the like have large molecular weights, and contain many polymers of 250,000 or more. on the other hand,
It is said that a material applicable as a pulp raw material used as a raw material for papermaking has a molecular weight of 250,000 or more, preferably 500,000 or more. Further, it is said that a material applicable as a biodegradable plastic, which is attracting attention as a substitute material for petroleum-based plastics, has a molecular weight of 250,000 or more. Therefore, if useful macromolecules having a molecular weight of 250,000 or more can be efficiently obtained from cells of microalgae, they can be sufficiently utilized as the above pulp raw material or biodegradable plastic raw material.

The large-scale cultivated microalgae are dehydrated by a filter press or centrifugation if necessary, and the cells (cell walls) are first crushed. The method for crushing the cell wall of the microalgae is preferably one or more methods selected from an ultra-high pressure pressing method, a breaking method using a high-speed rotary blade, an ultrasonic crushing method, and an enzymatic decomposition method.

The high-pressure pressing method involves placing microalgae in a container,
It is a method of physically destroying the cell wall by pressing at ultrahigh pressure, and can be carried out using a pressing device suitable for this type of application. In particular, microalgae are placed in a flexible sealed container, hydrostatically pressed at high pressure, and then the pressure is rapidly reduced to cause a rapid pressure difference between the inside and outside of the cell wall of the microalgae to crush the cell wall. The method is preferred. With such a hydrostatic pressure method, it is possible to completely crush the cell wall without heating the microalgae and without causing a chemical change such as oxidation.

In the ultrasonic crushing method, the cell wall of the microalgae is crushed by ultrasonic vibration, and the liquid in which the microalgae is suspended is preferably sonicated for crushing. By this ultrasonic disruption, cells can be easily disrupted, but the components may be slightly altered by the generation of heat or oxidation.

The breaking method includes a method of inserting a high-speed rotary blade into a liquid in which microalgae is suspended, a method of crushing a slurry of microalgae with a high-speed rotary blade, a method of cutting dried or frozen microalgae. Can be used.

The enzymatic decomposition method is a method in which a cell wall decomposing enzyme such as cellulase is caused to act on microalgae to decompose the cell wall to crush cells. This is already used in crushing cells such as chlorella. It can be carried out by the same operation using an enzyme.

The cell lysate of microalgae is dried if necessary, and then an organic solvent is added to extract components soluble in the organic solvent such as lipids. The organic solvent used here has low toxicity to the human body and is an organic solvent that is acceptable in food production,
For example, ethanol, acetone, n-hexane is used. By using these safe organic solvents,
Even if the finally obtained useful polymer is eaten, the remaining organic solvent does not adversely affect the human body, and the useful polymer becomes highly safe for the human body.

By extracting with the above-mentioned organic solvent, most of the lipids and pigments of the components of the microalgae are extracted into the organic solvent, and a part of the polymer containing proteins and polysaccharides is also extracted. . This extraction is performed by standing or stirring at 0 ° C to 40 ° C, preferably at room temperature when it is necessary to prevent alteration of proteins and the like. After extraction for a predetermined time, the mixture of the crushed product and the organic solvent is centrifuged to separate the residue and the organic solvent phase. Then, a predetermined amount of organic solvent is added again to the separated residue, and extraction and centrifugation are performed. This extraction and centrifugation are repeated once or more, preferably about 3 to 6 times.

The finally remaining residue is used in the next step.
Organic solvent phases separated by one or more extractions are combined, and the organic solvent is distilled, purified, separated, and reused. After distilling and separating the organic solvent, components mainly composed of lipids and pigments are obtained. This component can be used as a fuel by separating lipids, as a raw material for fats and oils, and as a raw material for extracting natural pigments. Furthermore, as will be demonstrated in an experimental example described later, since the organic solvent phase also contains a large amount of a polymer having a molecular weight of 250,000 or more, the contained polymer is separated from lipids, etc. It may be used as a useful polymer for producing degradable plastics.

The residue separated by extraction with an organic solvent and centrifugation is mainly composed of proteins, fiber components, polysaccharides, etc., and most of the pigments have been extracted and decolorized to white to pale yellow. In this state, it can be used as a filling material in the production of pulp raw materials and biodegradable plastics. In this example, from this residue, a useful polymer mainly composed of protein and having a molecular weight of 250,000 or more is purified and separated.

The organic solvent is removed from this residue, preferably the solvent is distilled off at a low temperature and dried, and then water or a neutral buffer such as a phosphate buffer is added to extract a neutral water-soluble component. Then, the mixture is extracted with stirring for a predetermined time and then centrifuged to separate the buffer solution phase (aqueous phase) and the residue. This extraction and centrifugation
The neutral water-soluble component is extracted from the above residue by repeating at least once, preferably 2 to 4 times at room temperature. The buffer phase (aqueous phase) separated by a plurality of extractions is combined, concentrated under reduced pressure, and dried if necessary to obtain a useful polymer containing a water-soluble protein as a main component.

The separated residue contains proteins and fibers which are insoluble in the neutral aqueous solution. To further separate and purify useful polymers from this residue, an alkaline aqueous solution such as an aqueous NaOH solution is added to this residue to extract the alkali-soluble component, and the mixture is extracted by stirring for a predetermined time and then centrifuged to remove an alkaline aqueous solution phase (NaOH Phase) and the residue are separated. This extraction and centrifugation are repeated once or more at room temperature, preferably 2 to 4 times to extract the alkali-soluble component from the above residue. The separated residue contains fiber components that do not change in alkaline aqueous solution and proteins that have been partially modified by alkali but remain insoluble, and are used as they are to produce pulp raw materials and biodegradable plastics. Can be used as a filling material in.

The alkaline aqueous solution phases (NaOH phase) separated by a plurality of extractions are combined, and an organic acid such as acetic acid or an inorganic acid such as hydrochloric acid, preferably acetic acid is added to adjust the pH of the solution to 7 or less. Preferably, the pH is adjusted to about 4 and an alkali-soluble and acid-insoluble protein is precipitated, and the precipitate is separated by centrifugation to separate the precipitate composed of the precipitated protein from the supernatant water.

Soluble protein is contained in the separated supernatant water, and by freeze-drying the supernatant water, it is used as a polymer component in the production of pulp raw materials or biodegradable plastics, or as a paste or coagulant. It is possible.

The separated precipitate is placed in a dialysis membrane such as a cellulose membrane, immersed in water or a neutral buffer solution and dialyzed to remove low molecular weight components. After this dialysis, the precipitate (often liquefied by dialysis) is lyophilized to obtain a useful polymer mainly composed of protein.

FIG. 2 is a diagram showing a second embodiment of the method for producing a useful polymer using microalgae according to the present invention. In this embodiment, lipids are extracted from the components contained in the microalgae. It illustrates a process suitable for obtaining a decolorization residue that can be used as a pulp raw material or a filling material in the production of biodegradable plastics and that is a raw material for proteins and polysaccharides.

In this embodiment, the same microalgae as in the previous embodiment are used, and the cells (cell wall) of the microalgae are first crushed. This cell disruption method is carried out in the same manner as in the previous example. Then, to the microalgae in which the cells are crushed, an organic solvent acceptable in food production, for example, ethanol, acetone, n
An organic solvent consisting of one or more types of hexane, particularly preferably acetone, is added, and the mixture is heated to 30 ° C. to 80 ° C., preferably about 60 ° C. to extract a component soluble in the organic solvent.

The mixture is then centrifuged to separate the residue and the organic solvent phase. The separated residue can be used as a filling material in the production of pulp raw materials and biodegradable plastics, and also becomes a raw material for proteins and polysaccharides. The organic solvent phase is concentrated by distilling off the solvent with a rotary evaporator or the like to obtain a residue containing fats and pigments as main components. This residue can be used as a raw material for lipids and fatty acids, and the mixed pigments such as chlorophyll and carotenoids are purified and separated to be used as an industrial raw material. Further, the recovered solvent is subjected to a purification treatment if necessary and used for extraction again.

FIG. 3 is a view showing a third embodiment of the method for producing a useful polymer using microalgae according to the present invention. In this embodiment, hot water-soluble polysaccharides among the components contained in the microalgae. Exemplifies a process suitable for obtaining In this example, as in the first example, the cells of the starting material microalgae were crushed, and then the crushed cells of the microalgae were used as an organic solvent acceptable in food production, such as ethanol, acetone, or n-hexane. 1 or 2 or more kinds of organic solvents are added and extraction is performed by heating, preferably by refluxing. Then, the solid content is separated and dried to obtain a dry residue (defatting residue). When defatting by refluxing, the cell wall may be crushed by crushing the solid content by adding an organic solvent to reflux and defatting without crushing the cells of the microalgae.

Then, water or a neutral buffer solution is added to the above degreased and dried residue, and the temperature is 40 to 100 ° C., preferably 6
Hot extraction is performed at a temperature of about 0 ° C. to extract hot water-soluble polysaccharides in the residue. Next, after setting the temperature to about 37 ° C,
Deproteinize by adding proteolytic enzyme. As the proteolytic enzyme used here, various commercially available enzyme agents may be used, and the pH of the extract may be adjusted according to the pH suitable for the enzyme agent. After allowing the protease to act for a predetermined time, the liquid is boiled to inactivate the enzyme.

Next, this liquid is centrifuged to separate into supernatant water containing hot water-soluble polysaccharides and a residue mainly containing insoluble components such as fiber. This residue can be used as a filling material in the production of pulp raw materials and biodegradable plastics. In addition, in this centrifugation, when the hot water-soluble polysaccharide is precipitated as the temperature decreases, it is desirable to perform the centrifugation while maintaining the temperature of about 60 ° C.

The separated supernatant water containing the hot water-soluble polysaccharide is concentrated under reduced pressure, and the obtained concentrate is dialyzed by placing it in a dialysis membrane such as a cellulose membrane to remove low molecular weight components. After this dialysis, ethyl alcohol is added to the dialysate to wash the hot water-soluble polysaccharide. In addition, when the dialysate is in a liquid state and the hot water-soluble polysaccharide is in a state of being dissolved therein, when ethyl alcohol is added thereto, an alcohol-insoluble polysaccharide is precipitated, so the amount of alcohol to be added is equal to that of the dialysate. It is desirable that the amount is equal to or more than the above, and after mixing, leave still for a sufficient time.

Then, the alcohol liquid in which the hot water-soluble polysaccharide is mixed is centrifuged to separate into an alcohol phase and a residue containing the hot water-soluble polysaccharide as a main component. The separated residue is washed with ethyl alcohol if necessary, dried and pulverized to obtain a hot water-soluble polysaccharide. The hot water-soluble polysaccharides thus obtained, depending on the type of microalgae as a raw material, a polysaccharide having a sugar as a basic unit, a polysaccharide having a sugar and uronic acid as a basic unit, a mucopolysaccharide, and the like. Different polysaccharides are obtained.

FIG. 4 is a view showing a fourth embodiment of the method for producing a useful polymer using microalgae according to the present invention. In this embodiment, among the components contained in the microalgae, proteins are mainly used. It illustrates a process suitable for obtaining both a useful polymer having a component and a useful polymer having a hot water-soluble polysaccharide as a main component. In this example, first, an organic solvent, preferably acetone, is added to the microalgae to further disrupt the cells,
The lipid is heated and extracted by refluxing. In addition, the cell wall may be crushed by adding an organic solvent and refluxing to degrease and crush the solid content without crushing the cells of the microalgae.

After warm extraction for a predetermined time, the mixture is centrifuged to separate it into an acetone phase and a residue. The acetone phase is
The same treatment as the treatment of the organic solvent phase in the second embodiment shown in FIG. 2 is performed. The separated residue is dried at a low temperature, and then water is added to heat and extract a useful polymer containing a protein and a hot water-soluble polysaccharide. The extraction temperature at this time is 30 to 6
It is desirable to set the temperature to about 0 ° C. so that the protein is not denatured and the soluble polysaccharide can be dissolved and extracted.

Next, this mixture is centrifuged to separate into a protein-containing residue and a hot water-soluble polysaccharide-containing supernatant water. The separated residue is extracted by adding a phosphate buffer to carry out the useful polymer production process shown in FIG. 1 to produce a useful polymer containing protein as a main component. The separated supernatant water is combined with unnecessary fractions in FIG. 1, such as fraction 4 in FIG. 1, and the production process of useful polymer shown in FIG. 3 is carried out. To produce useful polymers.

In this example, defatted microalgae were extracted by heating and centrifuged to separate the residue containing protein and the supernatant water containing hot water-soluble polysaccharide from which protein was the main component. To produce a useful polymer having a hot water-soluble polysaccharide as a main component from the supernatant water. Moreover, the fraction containing a soluble polysaccharide, which is unnecessary when producing a useful polymer containing a protein as a main component from the residue, is treated by combining with the supernatant water to effectively utilize microalgae. As a result, the amount of the extraction residue produced is smaller than that in the case where a useful polymer containing a protein as a main component or a useful polymer containing a hot water-soluble polysaccharide as a main component is solely produced from microalgae.

FIG. 5 shows an embodiment of a papermaking method using the useful polymer according to the present invention. In this example,
First, a raw material pulp liquid containing a useful polymer obtained by either the microalgae itself or the above-described method for producing a useful polymer, a separated residue or other fiber component, and a paste is prepared.

The useful polymer used here may be one or both of a useful polymer having a protein as a main component and a useful polymer having a hot water-soluble polysaccharide as a main component. The separated residue or other fiber component is an insoluble component mainly composed of cellulose, which is unnecessary in the production of useful polymers,
One or more selected from wood pulp, recycled fiber, synthetic fiber, plant fiber other than wood such as bacas fiber, and material obtained by cutting a film-like material obtained by drying and solidifying a useful polymer into a fibrous shape are used. . Furthermore, as the pastes added to these, starch paste, alginic acid and protein modified products,
Synthetic resins such as polyacrylic acid salts and polyethylene oxide, carboxymethyl cellulose (hereinafter abbreviated as CMC), and the like are used, and CMC is particularly preferable.

The microalgae itself or these useful polymers, the fiber component, and the paste are mixed (mixed) with water, and further, if necessary, an inorganic flocculant such as aluminum sulfate or a polyacrylate salt. The organic polymer coagulant (2) is added to facilitate coagulation of the fiber component to obtain a raw pulp liquid. The ratio of the useful polymer to the fiber component is not particularly limited, but it is desirable to increase the fiber content when preparing a paper having a certain strength.

Next, using the prepared raw material pulp liquid,
Paper is manufactured by paper making and drying. This papermaking process can be performed in the same manner as in papermaking in conventional papermaking using wood pulp, and can be carried out using a Fourdrinier paper machine, a round net paper machine, or the like used in general papermaking.

Through the paper making and drying steps, a paper containing a useful polymer is produced. Depending on the compounding ratio of the fiber component and the useful polymer, the resulting paper has various structures such as a structure similar to ordinary paper in which the fiber components are entangled, to a structure like a non-woven fabric in which each fiber is bonded to the polymer. Paper is obtained. These papers can be used like ordinary papers.

FIG. 6 shows an embodiment of a method for producing a biodegradable plastic using the useful polymer according to the present invention. In this example, first, a useful polymer obtained by any of the microalgae itself or the method for producing a useful polymer described above, and a separated residue or other fiber component,
A biodegradable plastic raw material liquid containing a coagulant is prepared.

The useful polymer used here may be one or both of a useful polymer having a protein as a main component and a useful polymer having a hot water-soluble polysaccharide as a main component. The separated residue or other fiber component is an insoluble component mainly composed of cellulose, which is unnecessary in the production of useful polymers,
One or more selected from wood pulp, recycled fiber, synthetic fiber, plant fiber other than wood such as bacas fiber, and material obtained by cutting a film-like material obtained by drying and solidifying a useful polymer into a fibrous shape are used. . Furthermore, as a coagulant added to these, starch paste, alginic acid, protein modified products, synthetic resins such as polyacrylic acid salt and polyethylene oxide, carboxymethyl cellulose (hereinafter referred to as CMC
Abbreviated as “) and the like, and CMC is particularly preferable.

The microalgae itself or these useful polymers, the fiber component, and the paste are mixed (mixed) with water to obtain a high-concentration biodegradable plastic raw material liquid.
The ratio of the useful polymer to the fiber component is not particularly limited, but when a plastic product having a certain level of strength is manufactured, it is desirable to increase the fiber content for preparation.

Next, this raw material liquid is put into a mold, solidified and dried to produce a biodegradable plastic. The useful polymer, the fiber component, and the paste are mixed with water by adding (mixing) to obtain a high-concentration biodegradable plastic raw material liquid. The ratio of the useful polymer to the fiber component is not particularly limited, but it is desirable to increase the fiber content when producing a plastic product having a certain level of strength. In order to solidify the raw material liquid, for example, injection molding is used in which the raw material liquid is heated to dissolve all the materials, and then the liquid is put into a mold, slowly cooled to solidify, and taken out from the mold and dried. To be Further, the shape of the molded product is not limited, and various shapes such as a block shape, a hollow shape (bottle etc.), a plate shape, a film shape, a linear shape, a bag shape can be formed.

The biodegradable plastic thus obtained is used in various applications as a substitute material for ordinary petroleum plastics. Since this biodegradable plastic is harmless and is easily decomposed by soil microorganisms even when it is discarded, it is possible to provide a plastic product that can be easily disposed of. Moreover, since the product contains proteins and polysaccharides as main components, it can be used as a fertilizer component and a soil conditioner as a result of being buried and decomposed by soil microorganisms.
The experimental examples according to the present invention will be described below.

(Experimental Example 1) Chlorococcum littorale was used as the microalgae,
A large amount of this alga was cultured and dehydrated to obtain bacterial cells. The dehydrated alga was treated according to the flow shown in FIG. First, the cells of the algae were crushed by a hydrostatic press, acetone was added to the cells, and the mixture was extracted with stirring at room temperature and centrifuged to separate into a residue and an acetone phase (3 to 6 times). The separated acetone phase (fraction 1) was subjected to column chromatography with a standard substance of known molecular weight. Figure 7 shows the separation conditions and the results.
It was shown to.

Next, 0.02 M phosphate buffer (pH 7) was added to the separated residue, and the mixture was extracted with stirring for 1 hour and then centrifuged to separate the residue and the buffer phase (three times). The separated buffer solution phase (fraction 2) was subjected to column chromatography in the same manner as the above-mentioned fraction 1. The separation conditions and the results are shown together in FIG.

Next, 0.5% NaO was added to the separated residue.
The H solution was added, and the mixture was extracted with stirring for 1 hour and then centrifuged to separate the residue and the NaOH phase (three times). The separated residue (fraction 3) was subjected to column chromatography in the same manner as the above-mentioned fraction 1. The separation conditions and the results are shown together in FIG.

Next, acetic acid was added to the separated NaOH phase to adjust the pH to about 4 to precipitate an alkali-soluble and hardly acid-soluble component, followed by centrifugation to precipitate and the supernatant water (fraction 4, Then, the precipitate was placed in a cellulose dialysis membrane, sealed, dialyzed in water for 2 days, and the dialyzed product was freeze-dried under vacuum. The obtained powder (fraction 5) was
It was dissolved in a phosphate buffer and subjected to column chromatography in the same manner as in the above Fraction 1. The separation conditions and the results are shown together in FIG.

As is clear from the chromatograms shown in FIGS. 7 to 10, any one of the fractions 1, 2, 3 and 5 separated according to the production flow of the useful polymer mainly containing the protein shown in FIG. In addition, it was revealed that a polymer having a molecular weight of 250,000 or more was present, and it was proved that a useful polymer sufficiently usable as a pulp raw material or a biodegradable plastic raw material was obtained.

(Experimental Example 2) Using the same algae as in Experimental Example 1, the following Table 1 is used according to the separation flow of lipid and residue shown in FIG.
Lipids were extracted using various solvents shown therein, and the degreasing rate and the color of the residue were compared.

[0068]

[Table 1]

As is clear from Table 1, acetone is most suitable as the organic solvent in view of the degreasing rate. It can be said that n-hexane and ethyl alcohol, which have a slightly low degreasing rate and are highly safe for the human body, are suitable organic solvents.

(Experimental Example 3) Using the same algae as in Experimental Example 1, the hot water-soluble polysaccharide (useful polymer) obtained by treating according to the production flow of the hot water-soluble polysaccharide shown in FIG. Column chromatography with standards. The separation conditions and the results are shown together in FIG. 11.

As is apparent from FIG. 11, the fraction separated according to the production flow of the useful polymer having the hot water-soluble polysaccharide as the main component shown in FIG. 1 contains a polymer having a molecular weight of 250,000 or more. It has been clarified that the useful polymer can be sufficiently used as a pulp raw material and a biodegradable plastic raw material.

(Experimental Example 4) Using the same alga as in Experimental Example 1, continuous extraction and separation of a useful polymer having a protein as a main component and a useful polymer having a hot water-soluble polysaccharide as a main component shown in FIG. The useful polymer was separated according to the flow of 1., and the residue production rate at that time was measured and compared with the residue production rate in each separation process of Experimental Examples 1 to 3 (FIGS. 1 to 3). The results are shown in Table 2.

[0073]

[Table 2]

As is clear from Table 2, algae are treated according to the flow shown in FIG. 4 to continuously extract a useful polymer containing protein as a main component and a useful polymer containing hot water-soluble polysaccharide as a main component. It was demonstrated that the separation yields a low residue production rate compared to other processes and enables the useful macromolecules to be separated from algae at a high rate.

[0075]

Industrial Applicability As described above, the method for producing a useful polymer using microalgae according to the present invention uses microalgae useful in CO ₂ immobilization as a raw material, and the cells of the microalgae are treated with an organic solvent. In addition to disrupting the cells, the mixture is centrifuged to separate an organic phase soluble in an organic solvent and an insoluble residue, and the insoluble residue is purified as it is or by adding various purification processes to obtain a useful polymer. To get This useful polymer is mainly composed of a protein having a molecular weight of 250,000 or more and a derivative thereof contained in microalgae or a hot water-soluble polysaccharide and a derivative thereof having a molecular weight of 250,000 or more.
These useful polymers can be formed into a film-like polymer film by spreading an aqueous solution thinly and drying or heating, or by flowing into a mold of a desired shape and solidifying to obtain articles of various shapes. You can Therefore,
According to the present invention, a large amount of surplus algae obtained from a CO ₂ -immobilization plant or the like can be used to efficiently produce a useful polymer that can be used as a raw material for pulp for papermaking or a raw material for biodegradable plastics.

In this method for producing a useful polymer, the useful solvent finally obtained is obtained by using one or more highly safe solvents selected from ethyl alcohol, acetone and n-hexane as the organic solvent. Even if a polymer is eaten, the residual organic solvent will not adversely affect the human body, and the useful polymer will be highly safe for the human body, so the range of application of the useful polymer can be expanded. it can.

Further, the papermaking method using the useful polymer according to the present invention prepares a raw material pulp liquid containing the microalgae itself or the above useful polymer, the separated residue or other fiber component, and the sizing agent. Then, papermaking is performed with this raw material pulp liquid, and then the paper is dried to produce paper, whereby paper can be produced without using wood pulp or by significantly reducing the amount of wood pulp used.

Further, the method for producing a biodegradable plastic using the useful polymer according to the present invention comprises microalgae itself or the useful polymer described above, a separated residue or other fiber component, and a coagulant. A biodegradable plastic raw material liquid is prepared, and the raw material liquid is put into a mold, solidified, and dried to produce a plastic-like product. Since it is easily decomposed by, a plastic product that can be easily disposed of can be provided. Moreover, since the product contains proteins and polysaccharides as main components, it can be used as a fertilizer component and a soil conditioner as a result of being buried and decomposed by soil microorganisms.

[Brief description of drawings]

FIG. 1 is a flow chart illustrating a first embodiment of a method for producing a useful polymer according to the present invention.

FIG. 2 is a flow chart illustrating a second embodiment of the method for producing a useful polymer according to the present invention.

FIG. 3 is a flow chart illustrating a third embodiment of the method for producing a useful polymer according to the present invention.

FIG. 4 is a flow chart illustrating a fourth embodiment of the method for producing a useful polymer according to the present invention.

FIG. 5 is a flow chart illustrating a paper manufacturing method using a useful polymer according to the present invention.

FIG. 6 is a flow diagram illustrating a method for producing a biodegradable plastic using the useful polymer according to the present invention.

FIG. 7 is a column separation chromatogram of fraction 1, showing the results of an experimental example related to the production method of FIG. 1.

FIG. 8 is a column separation chromatogram of fraction 2, showing the results of an experimental example related to the production method of FIG. 1.

9 is a column separation chromatogram of fraction 3, showing the results of an experimental example relating to the production method of FIG. 1. FIG.

10 is a column separation chromatogram of fraction 5 showing the results of an experimental example relating to the production method of FIG. 1. FIG.

FIG. 11 is a column separation chromatogram of the hot water-soluble polysaccharide obtained, showing the results of the experimental example according to the production method of FIG. 3.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Kodama 75-1 Hirata No.3, 75-1, Hirata, Kamaishi-shi, Iwate Marine Biotechnology Research Institute, Kamaishi Research Center

Claims (16)

[Claims] 1. A microalgal cell is crushed, an organic solvent is added to the crushed cell to extract a component soluble in the organic solvent, and then the mixture is centrifuged to separate an organic solvent phase and a residue. Then, a useful polymer contained in the organic solvent phase is obtained, which is a method for producing a useful polymer using microalgae. 2. A microalgal cell is crushed, an organic solvent is added to the crushed cell to extract a component soluble in the organic solvent, and then the mixture is centrifuged to separate an organic solvent phase and a residue. Then, water or a neutral buffer solution is added to the residue to extract a water-soluble component, and then the mixture is centrifuged to separate an aqueous phase and a residue, and a useful polymer contained in the aqueous phase is separated. A method for producing a useful polymer using microalgae, which is characterized by being obtained. 3. Microalgae cells are crushed, an organic solvent is added to the crushed cells to extract a component soluble in the organic solvent, and then the mixture is centrifuged to separate an organic solvent phase and a residue. Then, water or a neutral buffer is added to the residue to extract water-soluble components, and then the mixture is centrifuged to separate an aqueous phase and a residue. A method for producing a useful polymer using microalgae, which comprises extracting a soluble component and then centrifuging to separate it into an alkaline aqueous phase and a residue to obtain a useful polymer contained in the residue. 4. A cell of a microalgae is disrupted, an organic solvent is added to the disrupted cell to extract a component soluble in the organic solvent, and then the mixture is centrifuged to separate an organic solvent phase and a residue. Then, water or a neutral buffer is added to the residue to extract water-soluble components, and then the mixture is centrifuged to separate an aqueous phase and a residue. Soluble components were extracted and then centrifuged to separate an alkaline aqueous phase and a residue. Then, an acid was added to the alkaline aqueous phase to adjust the pH to 7 or less, and then centrifugal separation was performed to separate a precipitate from a supernatant. A method for producing a useful polymer using microalgae, which comprises obtaining a useful polymer contained in the supernatant. 5. A cell of a microalgae is disrupted, an organic solvent is added to the disrupted cell to extract a component soluble in the organic solvent, and then the mixture is centrifuged to separate an organic solvent phase and a residue. Then, water or a neutral buffer is added to the residue to extract water-soluble components, and then the mixture is centrifuged to separate an aqueous phase and a residue. Soluble components were extracted and then centrifuged to separate an alkaline aqueous phase and a residue. Then, an acid was added to the alkaline aqueous phase to adjust the pH to 7 or less, and then centrifugal separation was performed to separate a precipitate from a supernatant. Then, the precipitate is dialyzed and further dried to obtain a useful polymer, which is a method for producing a useful polymer using microalgae. 6. Crushing microalgal cells, adding an organic solvent to the crushed cells to extract components soluble in the organic solvent, and then centrifuging the mixture to separate an organic solvent phase and a residue. Then, water or a neutral buffer solution is added to the residue for hot extraction, and then a proteolytic enzyme is added to decompose the protein, and the enzyme-treated product is centrifuged to separate the residue and the supernatant. Separation, then the supernatant is concentrated, and the concentrate is dialyzed, alcohol is added, and then centrifugal separation is performed to separate the precipitate mainly composed of hot water-soluble polysaccharides from the alcohol phase, A method for producing a useful polymer using microalgae, which comprises obtaining a useful polymer from the precipitate. 7. A cell of a microalgae is disrupted, an organic solvent is added to the disrupted cell to extract a component soluble in the organic solvent, and then the mixture is centrifuged to separate an organic solvent phase and a residue. Then, water or a neutral buffer solution is added to the residue for hot extraction, and the residue is centrifuged to contain a useful polymer having a protein as a main component and a supernatant containing a hot water-soluble polysaccharide. Using a microalgae characterized by obtaining a useful polymer containing protein as a main component from the residue and obtaining a useful polymer containing hot water-soluble polysaccharide as a main component from the supernatant. A method for producing a useful polymer. 8. The method for producing a useful polymer using microalgae according to claim 1, wherein the organic solvent is selected from ethyl alcohol, acetone, and n-hexane.
A method for producing a useful polymer using microalgae, which comprises one kind or two or more kinds of solvents. 9. The method for producing a useful polymer using the microalgae according to claim 1, wherein the microalgae are axial algae, green algae, brown algae, diatoms, yellow-green algae, true eye spot algae.
A method for producing a useful polymer using microalgae, which is one kind selected from the group of haptoalga, red algae, and cyanobacteria. 10. The method for producing a useful polymer using microalgae according to any one of claims 1 to 7, wherein the means for crushing the cells of the microalgae is rupture by an ultra-high pressure pressing method, a high-speed rotary blade, or the like. Method, ultrasonic crushing method, enzymatic decomposition method, and one or more kinds selected from the above, a method for producing a useful polymer using microalgae. 11. The method for producing a useful polymer using microalgae according to any one of claims 1 to 7, wherein the useful polymer is a protein having a molecular weight of 250,000 or more and its derivative or a heat having a molecular weight of 250,000 or more. A method for producing a useful polymer using microalgae, which comprises a water-soluble polysaccharide and a derivative thereof as main components. 12. The microalgae itself or any one of claims 1 to 1.
1. A raw material pulp liquid containing a useful polymer obtained by the method according to any one of 1 to 3 above, a separated residue or other fiber component, and a sizing agent is prepared, and papermaking is performed with this raw material pulp liquid. A paper-making method using a useful polymer, which comprises drying to produce paper. 13. The paper manufacturing method according to claim 12, wherein the sizing material is a water-soluble polymer fiber material such as carboxymethyl cellulose which is easily biodegradable. . 14. The paper manufacturing method according to claim 12 or 13, wherein a coagulant such as aluminum sulfate is added to the raw material pulp liquid. 15. Microalgae itself or claims 1 to 1
1. Prepare a biodegradable plastic raw material liquid containing the useful polymer obtained by the method described in any one of 1, the separated residue or other fiber components, and a coagulant, and put the raw material liquid in a mold. A method for producing a biodegradable plastic using microalgae or a useful polymer separated therefrom, which comprises producing a biodegradable plastic by solidifying and drying. 16. The method for producing a biodegradable plastic according to claim 15, wherein the coagulant is a biodegradable water-soluble polymer fiber material such as carboxymethyl cellulose. Method for making flexible plastics.