JPH10226702A - Method for restoring dried cellulose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restore a film of a dried cellulose to a cellulose having properties such as water retentivity, viscosity and emulsifying power equivalent to those of the undried cellulose by macerating a film prepared by drying a bacterial cellulose obtained by culturing cellulose-producing bacteria, a microfibrous cellulose or a parenchymatic cell cellulose by shearing to give an increased degree of shearing. SOLUTION: Once a bacterial cellulose, a microfibrous cellulose or a parenchymatic cell cellulose is dried, it can not be restored simply by the addition of water because of the existence of hydrogen bonding among fibers. This invention provides a method for restoring a dried product of such a cellulose to one having the properties of the initial undried cellulose. The maceration of a cellulose is estimated to be a phenomenon of deformation and disintegration by the action of external mechanical force and can be accomplished by using a means which produces high shear strength, such as a mixer, a polytron or an ultrasonic oscillator. The undried cellulose used is desirably a previously macerated one. It is necessary that the drying is performed to an extent that the dried product has a water activity of at most 0.9 at which microorganisms are not viable. The drying method may be a known one.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cellulosic substance (hereinafter, referred to as "bacterial cellulose" or "BC") which can be produced by culturing a cellulosic bacterium, and a microfibrous cellulose (hereinafter, "MFC"). ) Or parenchyma cell cellulose (hereinafter "PCC").
Also called. ), Wherein the dried product is subjected to shearing treatment and disintegrated to provide a method for restoring the cellulose.

[0002]

2. Description of the Related Art BC (bacterial cellulose) is edible and tasteless and odorless, so it is used in the field of foods, and because of its excellent water-based dispersibility, it maintains the viscosity of foods, cosmetics, paints, etc. It has industrial value in strengthening dough, retaining moisture, improving food stability, as a low-calorie additive or as an emulsification stabilizing aid. BC has a fibril fragment width of 2 times as compared to cellulose produced from wood pulp or the like.
It is characterized by a small digit. Accordingly, the dissociated product of BC has various industrial uses as a reinforcing agent for polymers, especially aqueous polymers, based on such structural and physical characteristics of fibrils. A material obtained by solidifying such a cellulosic disagglomerated product into a paper or solid form exhibits a high tensile modulus, so that excellent mechanical properties based on the structural characteristics of fibrils are expected, and there are applications as various industrial materials. . On the other hand, MFC
Is conventionally known as microcellulose having a size of about 0.1 to 10 microns, and is excellent in aqueous dispersibility, so that it retains the viscosity of foods, cosmetics or paints, strengthens food material dough, It is industrially useful as a preservative, improved food stability, a low-calorie additive or an emulsion stabilizing aid.

[0003]

However, when such a disintegrated product of BC, PCC or MFC is to be handled in a wet state, the weight of the disintegrated product is several to several hundred times the weight of the cellulose component. Increased storage space, increased storage and transportation costs due to the presence of solvents such as water,
There are various problems such as decomposition by microorganisms during storage. Therefore, if the BC, PCC or MFC can be changed from a wet state to a dry state, it is expected that the above problem will be solved. However, BC and the like are composed of very fine cellulose fine fibers. It is presumed that the fine fibers have a width of about 100 nm and a thickness of about several nm based on the results of observation with a transmission electron microscope. Furthermore, it is reported that the width is 20 to 50 nm in scanning electron microscope observation. As is well known, cellulose is a homopolymer formed by β-bonding the carbons at positions 1 and 4 of glucose. Hydroxyl groups are bonded to positions 2, 3, and 6 of the glucose residue, and hydrogen bonds are formed between these hydroxyl groups and oxygen atoms in the pyranose ring of glucose. Moisture exists between the fine fibers, but when these waters are removed during the drying process, hydroxyl groups and oxygen atoms also exist on the surface of the fine fibers. A hydrogen bond is also formed. Ribbon-shaped fine fibers of bacterial cellulose, parenchyma cell cellulose and microfibrous cellulose are very thin compared to ordinary cellulose fibers, for example, vegetable pulp fibers, and have a large surface area, and therefore, a portion contributing to hydrogen bonding. Will increase,
Hydrogen bonds between the fine fibers are very strong as compared with ordinary pulp fibers and the like.

[0004] Therefore, once the BC is dried, the bond between the fine fibers is strong, so that simply adding water does not restore the original wet state. Speaking in macroscopic form, BC obtained by stationary culture is in the form of a gel film, BC obtained by stirring culture is in the form of a slurry, and the disintegrated product obtained by disintegrating both is in the form of a slurry. It does not return to the original state even if water is added to it and the film remains as it is. For this reason, it was extremely difficult for the BC which was simply condensed after drying, to restore various properties such as solubility, dispersibility, sedimentation degree and viscosity to the state before drying. PCC
And MFC also had similar problems. As means for solving this problem, conventionally, besides the freeze-drying method and the critical point drying method, a method of substituting with an organic solvent followed by drying (Japanese Patent Laid-Open No. Hei 6-233691) has been proposed. The feature of these methods is that the water between the BC fine fibers is made to be in an ice state and then dried, or by replacing the water with a solvent, the hydrogen bond between the fine fibers formed during drying is reduced. This is to prevent occurrence. However, these methods required enormous energy and complicated processes. As a method for improving these points, there has been proposed a method of adding a third component other than BC and water to an aqueous suspension of bacterial cellulose, followed by dehydration drying (Japanese Patent Application No. 7-288058). Also, it has been reported that when a high-speed shearing force is applied to BC in a dry state to disintegrate the same, the same paper strength enhancing effect (sheet strength) as that of the disintegrated product obtained by disintegrating the gel can be obtained (Japanese Patent Laid-Open No. Hei 5 (1994)). -51885).

[0005]

According to the present invention, there is provided a method for measuring a fixed amount (value).
By disintegrating the dried bacterial cellulose, microfibrous cellulose or soft tissue cell cellulose by applying the above shearing treatment, excellent properties such as water retention, viscosity and emulsifying power that these celluloses had before drying. Have been found, and the present invention has been completed.
That is, the present invention provides a method for restoring bacterial cellulose, comprising dissolving bacterial cellulose in a dry state, microfibrous cellulose or soft tissue cell cellulose by applying a shearing treatment such that the degree of shearing is increased. It relates to a cellulose suspension thus reconstituted. The "degree of shearing" in the shearing treatment of the present invention is determined by utilizing the viscosity decrease accompanying the shearing treatment of the polyacrylamide solution. First, a 0.05% by weight aqueous solution of polyacrylamide (Acrypers, manufactured by Diafloc Co., Ltd.) is prepared. For dissolution, a method of performing very gentle stirring at room temperature for 2 hours is used. 300 ml of this solution was placed in a 300 ml tall beaker, and a B-type viscometer (manufactured by Tokimec) was used.
Rotor No. 1, guarded, measure viscosity at 60 rpm, 30 ° C. The value one minute after the rotor of the viscometer starts to rotate is defined as a representative value of the viscosity. Using this polyacrylamide solution measuring system, the viscosities before and after each shearing treatment are measured, and the difference is defined as "degree of shearing". Therefore, when a device that generates a high shear force is used, a relatively short shearing process is sufficient. In the method of the present invention, the "degree of shear" is about 5 mPa.s or more, preferably about 20 mPa.s or more, more preferably 35 mPa.s or more, and even more preferably 50 mPa.s or more. For the shearing treatment, a device known to those skilled in the art, for example, a stirrer, a double cylindrical crusher (Polytron), a blender with a blade, a homogenizer, a high-pressure homogenizer, an ultrasonic crusher, an ultrasonic oscillator, or the like is used. However, any device that generates a high shear force may be used. The shearing treatment is usually performed in a state where cellulose is in an aqueous suspension, and the concentration of cellulose and the like at that time can be appropriately selected by those skilled in the art.

[0006] In the present invention, the “dry” state is defined as
It is not absolutely dry with no water contained in the dried product. That is, it refers to a case where the content is about 25% or less based on the total weight of BC and the like and the third component contained in the dried product. The appearance of the dried product in such a state is almost dry.
BC and the third component of the present invention often have a function of adsorbing moisture due to having a polar group such as a hydroxyl group in the molecule, or have a low molecular weight such as water of crystallization. In order to retain water in the form, even if it is dried with the method and apparatus described above and dried at first glance, it is considered to be dry, but if left in normal air, Adsorbs water vapor to reach an equilibrium state. When storage is required, the water activity value of the dried product of the present invention must be lower than or equal to a level at which microorganisms cannot grow. A water activity value of at most 0.9 or less, desirably 0.75 or less is required. The drying method may be any conventionally known method, and examples thereof include spray drying, pressing, air drying, hot air drying, and vacuum freeze drying. The following is an example of the drying device. That is, continuous tunnel dryer, band dryer, vertical dryer, vertical turbo dryer, multi-stage disk dryer,
Batch-type box-type drying equipment such as through-air drying equipment, rotary drying equipment, flash drying equipment, spray drying equipment, cylindrical drying equipment, drum drying equipment, screw conveyor drying equipment, rotary drying equipment with heating tubes, vibration transport drying equipment, etc. Drying apparatuses such as a through-air drying apparatus, a vacuum box-type drying apparatus, and a stirring drying apparatus can be used alone or in combination of two or more. Examples of a method of supplying thermal energy to the object to be dried in drying include, for example, direct heating, radiant heating, and indirect heating.
Of these, infrared heating, microwave heating and the like are particularly desirable from the viewpoint of energy efficiency.

[0007] In the method of the present invention, the cellulose in a dry state is preferably subjected to a defibration treatment in advance. The disintegration phenomenon of cellulose is considered to be a phenomenon in which a stress generated inside the cellulose due to a mechanical external force or the like deforms or breaks it. Accordingly, the disintegration treatment of cellulose can be performed by applying a mechanical external force to cellulose. Further, the disaggregation treatment can be carried out also by acid hydrolysis, enzymatic hydrolysis and bleach. The mechanical external force referred to herein includes, for example, stresses such as tension, bending, compression, torsion, impact, and shearing, but generally includes compression, impact, and shearing stress. When these mechanical external forces are actually applied to cellulose, it can be achieved by using, for example, an ultrasonic oscillator such as a mixer, a polytron or a self-excited ultrasonic pulverizer.

In the disaggregation process using a mixer, the mechanical external force is mainly an impact force caused by collision of the stirring blade with cellulose and a shear force generated by a displacement phenomenon caused by a difference in speed of the medium. In the disintegration process using Polytron, the mechanical external force is the compressive force of cellulose sandwiched between the external teeth and the internal teeth, the impact force of cellulose that collide with the high-speed rotating teeth, and the high-speed rotation of stationary external teeth. The shear stress generated in the medium existing in the gap between the internal teeth is mainly caused. In the disintegration by the ultrasonic pulverizer, the mechanical external force is mainly cavitation (cavity phenomenon) continuously generated in the medium due to the oscillation of the ultrasonic oscillating unit, and significant shear stress locally generated. The defibration treatment of the present invention can be performed by any method other than the above specific examples, as long as a constant load (mechanical external force) can be applied to cellulose.
Other disaggregation treatment conditions can be appropriately selected by those skilled in the art. Further, as described in Japanese Patent Application No. 7-160173, after the disaggregation treatment, the BC disintegrated material itself can be sieved with a screen having a predetermined opening for the purpose of adjusting the particle size.

Although the defibration treatment has been described above, the defibration treatment according to the present invention is carried out after stirring culture of the cellulose-producing bacteria.
It is obvious to those skilled in the art that the present invention is not limited to an independent secondary operation performed on bacterial cellulose separated and purified from a culture solution. That is, the stirring operation has an action of disintegrating bacterial cellulose as described later, and in the stirring culture employed in the present invention, it is sufficiently possible to disintegrate the bacterial cellulose even by the stirring action for the purpose of culture. Because there is. Furthermore, bacterial cellulose obtained by stirring culture is separated,
The same can be said for the operations of washing, purifying and transporting, and it should be noted that additional disaggregation treatment in these operations is also included in the disaggregation treatment of the present invention.

[0010] Cellulose producing bacteria used for producing bacterial cellulose in the present invention include, for example, BPR2
Acetobacter xylinum subspecies schlofermentans ( Acetobac
ter xylinum subsp. sucrofermentans ), Acetobacter xylinum ATCC23
768, Acetobacter xylinum ATCC 2376
9. Acetobacter pasteurianus ( A. pasteurianu)
s ) ATCC 10245, Acetobacter xylinum ATCC 14851, Acetobacter xylinum AT
CC11142 and Acetobacter xylinum ATC
C10821 and other acetic acid bacteria (genus Acetobacter), in addition to Agrobacterium, Rhizobium, Sarsina, Pseudomonas, Achromobacter, Alcaligenes, Aerobacterium, Azotobacter and Zugrea and NTG ( And various mutant strains created by performing a mutation treatment by a known method using, for example, nitrosoguanidine). In addition, BPR2001
The strain was deposited on February 24, 1993 at the Patented Microorganisms Depositary Center, National Institute of Bioscience and Human-Technology, Ministry of International Trade and Industry (Accession No. FERM P-13466), and then 199
Deposits based on the Budapest Treaty on the International Recognition of Deposits on Patent Proceedings dated February 7, 2004 (accession number FERM B
P-4545). Chemical mutation treatment methods using a mutagen such as NTG include, for example, Bio Factor
s, Vol. 1, p. 297-302 (1988) and J. Gen. Microbiol,
Vol. 135, p. 2917-2929 (1989). Therefore, those skilled in the art can obtain the mutant strain used in the present invention based on these known methods. The mutant strain used in the present invention can also be obtained by other mutation methods, for example, irradiation.

[0011] Among the cellulosic bacteria produced by the above-described method, the weight-average degree of polymerization in terms of polystyrene is 1.6 × 10 ⁴ or more by culturing with aeration and stirring.
Bacterial cellulose having a high degree of polymerization of preferably 1.7 × 10 ⁴ or more is produced, or is cultured by standing, so that the weight average degree of polymerization in terms of polystyrene is 2.0.
A strain producing bacterial cellulose having a high degree of polymerization of × 10 ⁴ or more is preferred. Among the bacteria producing bacterial cellulose having a high degree of polymerization that can be used in the present invention, BPR300
1A was deposited on June 12, 1995 with the Patented Microorganisms Depositary Center, National Institute of Bioscience and Human-Technology, Ministry of International Trade and Industry, and assigned accession number FERM P-14982. In general, it is known that the higher the degree of polymerization of a polymer, the higher the strength and elastic modulus of the polymer material. Similarly, in the case of bacterial cellulose, a film formed using bacterial cellulose having a high degree of polymerization as a raw material has a higher strength and elastic modulus than a film formed using bacterial cellulose having a relatively low degree of polymerization. Is high. Therefore, when it is desired to form a film having high strength and elastic modulus as the film of the present invention, the use of bacterial cellulose having a high degree of polymerization as described above provides a higher effect.

The weight-average degree of polymerization of various celluloses such as BC in the present invention can be measured by using GPC with RI built-in as a detector.
It is measured as follows using a system (Tosoh HLC-8020). Various cellulose samples were treated with fuming nitric acid-phosphorus pentoxide solution by WJ Alexander, RL Mitchell, Anal.
It is nitrated by the method of ytical chemistry 21, 12, 1497-1500 (1949). A nitrated cotton linter is used as a control. The cellulose nitrate is dissolved in THF (Wako Pure Chemicals first grade) at a concentration of 0.05%, and then filtered through a 1.0 μm pore size filter. THF is also used as the eluent for GPC. Flow rate is 0.5
ml / min, the pressure is 10-13 kgf / cm ² , and the sample injection volume is 100 μl. Column is TSKgel GMH
-Using HR (S) (7.5 ID x 300 mm x 2) and guard column (HHR (S)) (Tosoh Co., Ltd.) 35
Measure in ° C. For the molecular weight calculation, the relative molecular weight in terms of polystyrene is determined using standard polystyrene (Tosoh). Elution time (t) and logarithm of molecular weight (log M) using polystyrene having a molecular weight of 2 × 10 ⁷ to 2630
For the cubic equation: (log M = At ³ + Bt ² + Ct
+ D) to produce a standard curve.
Molecular weight: Tosoh's data processing machine (SC-8020)
The weight average molecular weight is calculated by a program (ver. From these molecular weight values, the weight average polymerization degree is calculated in consideration of the degree of substitution after nitration.

In the composition of the culture medium used for the culture, sucrose, glucose, fructose, mannitol, sorbitol, galactose, maltose, erythrit, glycerin, ethylene glycol, ethanol, etc. may be used alone or in combination as a carbon source. Can be. Furthermore, starch hydrolyzate containing these, citrus molasses, beet molasses, beet juice, sugarcane juice,
Juices such as citrus fruits can also be used in addition to sucrose. Further, as the nitrogen source, an organic or inorganic nitrogen source such as ammonium salts such as ammonium sulfate, ammonium chloride and ammonium phosphate, nitrate, urea and the like, or Bacto-Pepto can be used.
ne, Bacto-Soytone, Yeast-Ex
Nitrogen-containing natural nutrients such as tract and soybean may be used. As organic trace nutrients, amino acids, vitamins, fatty acids, nucleic acids, 2,7,9-tricarboxy-1H pyrrolo [2,3,5] -quinoline-4,5-dione, sulphite pulp waste liquor, ligninsulfonic acid, etc. are added. You may.

When an auxotrophic mutant that requires an amino acid or the like for growth is used, it is necessary to supplement a required nutrient. As the inorganic salts, phosphates, magnesium salts, calcium salts, iron salts, manganese salts, cobalt salts, molybdates, red blood salts, chelate metals and the like are used. Furthermore, inositol, phytic acid, and pyrroloquinoline quinone (PQQ) (Japanese Patent Publication No. 5-1718; Mitsuo Takai, Journal of Paper and Paper Technology Association, Vol. 42, No. 3, 237-2)
44), carboxylic acid or a salt thereof (Japanese Patent Application No. 5-1914).
No. 67), invertase (Japanese Patent Application No. 5-331491)
) And methionine (Japanese Patent Application No. 5-335564) can be added to the medium as appropriate. For example, when acetic acid bacterium is used as a production bacterium, the pH of the culture is controlled at 3 to 7, preferably around 5. The culture temperature is 10 to 40 ° C, preferably 25 to 3 ° C.
Perform at 5 ° C. The oxygen concentration supplied to the culture device is 1 to
100%, preferably 21 to 80%. Those skilled in the art can appropriately select the composition ratio of each component in the medium, the inoculation of the cells into the medium, and the like, depending on the culture method. Bacterial cellulose has been conventionally known as a culture method for culturing microorganisms, that is, stationary, shaking or aeration and stirring culture, and also known as a culture operation method, so-called batch fermentation method, fed-batch batch fermentation method, It can be produced by a repeated batch fermentation method, a continuous fermentation method, or the like.
In addition, as the stirring means, for example, an impeller (a stirring blade), an air lift fermenter, a pump-driven circulation of a fermentation broth, a combination of these means, and the like are used.

The stirring culture is a culture method in which the culture solution is stirred while the culture solution is stirred, and the structure of the bacterial cellulose, for example, the crystallization index is reduced and the amorphous part Changes to increase. As the stirring means, for example, an impeller, an airlift fermenter, a pump-driven circulation of fermentation broth, a combination of these means, and the like can be used. As a culture operation method,
There are a so-called batch fermentation method, a fed-batch batch fermentation method, a repeated batch fermentation method and a continuous fermentation method. Furthermore, a method for producing a cellulosic substance by circulating a culture solution containing bacterial cells between a culture apparatus and a separation apparatus described in Japanese Patent Application No. 6-192287 in the name of the present applicant. And separating the cellulosic substance, which is a product, from the cells and the culture solution, and culturing the cellulosic bacteria described in Japanese Patent Application No. 6-192288 in the name of the present applicant. A method for producing a cellulosic material by continuously extracting a culture solution from a culture system and supplying a new culture solution having substantially the same volume as the amount withdrawn during the culture period. The production method is characterized in that the concentration of the cellulosic substance in the culture solution is kept low.

As a tank for performing the stirring culture,
For example, stirring tanks such as jar fermenters and tanks,
A baffled flask, a Sakaguchi flask and an air-lift type stirring tank can be used, but are not limited thereto. In the stirring culture referred to in the present invention, simultaneously with stirring,
Ventilation may be performed if necessary. The aeration referred to here may be any of an oxygen-containing gas such as air and an oxygen-free gas such as argon and nitrogen. These gases may be used by those skilled in the art according to the conditions of the culture system. Will be selected as appropriate. For example, in the case of anaerobic microorganisms, if an inert gas is ventilated, the culture solution can be stirred by the bubbles. In the case of aerobic microorganisms, the culture solution can be agitated while supplying oxygen necessary for the growth of the microorganisms by aerating an oxygen-containing gas.

The bacterial cellulose obtained by the stirring culture is separated from the culture solution by a centrifugal separation method, a filtration method, or the like.
Bacterial cellulose may be collected together with the cells,
Further, a treatment for removing impurities other than the cellulosic substance including bacterial cells contained in the substance can be performed. To remove impurities, washing with water, pressure dehydration, washing with diluted acid, washing with alkali, treatment with bleach such as sodium hypochlorite and hydrogen peroxide, treatment with cell lysing enzymes such as lysozyme, sodium lauryl sulfate, Impurities can be almost completely removed from the cellulosic material by performing a treatment with a surfactant such as deoxycholic acid, washing with heat in the range of room temperature to 200 ° C., alone or in combination. The cellulosic material thus obtained in the present invention includes cellulose, a substance containing a heteropolysaccharide having cellulose as a main chain, and a substance containing glucan such as β-1,3, β-1,2. In the case of the heteropolysaccharide, components other than cellulose include hexoses such as mannose, fructose, galactose, xylose, arabinose, rhamnose, and glucuronic acid, pentoses, and organic acids. These polysaccharides may be a single substance, or two or more polysaccharides may be mixed by hydrogen bonding or the like.

It is also possible to add a third component other than water to the BC, PCC or MFC suspension before drying it. For this purpose, as already mentioned, the organic substance can be used as a solvent for the cellulose suspension instead of water. Examples of the third component include polar solvents such as alcohols and esters, acetone, hexane-based non-polar solvents, hydrophilic liquids, hydrophilic solids, water-insoluble substances and poorly water-soluble substances. Examples of the hydrophilic liquid used as the third component include glycerin, ethylene glycol, dimethyl sulfoxide, dimethylformamide, a surfactant, lactic acid, gluconic acid, and delta gluconolactone, and a mixture of one or more thereof. Further, hydrophilic solids that can be used as the third component include water-soluble substances such as water-soluble low-molecular and water-soluble polymers, and water-insoluble and hardly water-soluble substances.

Among these, the water-soluble small molecule includes, for example, saccharides (glucose, fructose, galactose, xylose, mannose, arabinose, sucrose, lactose, cellobiose, palatinose, maltose, gentiobiose, trehalose, rhamnose, oligosaccharide,
Isomaltooligosaccharide, soybean oligosaccharide, fructooligosaccharide, galactooligosaccharide, lactosucrose, coupling sugar, liquid sugar, cyclodextrin, sugar alcohol, sorbitol, erythritol, lactitol,
Maltitol, xylitol, mannitol, dursit), salts (sodium sulfate, ammonium sulfate, salt, calcium chloride, sodium bicarbonate, sodium carbonate, rossel salt), amino acids, amino acid salts, organic acids, organic acid salts, nucleic acids, nucleic acid salts , Alkyl ketene dimer, styrene-acrylic sizing agent, olefin-maleic anhydride sizing agent, higher fatty acid sizing agent, water resistant material composed of epoxy compound, fluorescent brightener, defoamer, antistatic agent, pigment, dye , Sulfuric acid band, aluminum chloride, sodium aluminate, basic aluminum chloride, basic polyaluminum hydroxide, alumina sol, water-soluble aluminum compound, ferrous sulfate, ferric chloride, and alkenyl succinic anhydride-based sizing agent and the like Refers to one or more mixtures.

The water-soluble polymer includes, for example, cellulose derivatives (carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, ethylcellulose), xanthan gum, xyloglucan, dextrin, dextran, carrageenan, locust bean gum, alginic acid, alginate, pullulan, Starch, potato starch, scum powder, positive starch, phosphorylated starch, corn starch, gum arabic, locust bean gum, guar gum,
Gellan gum, polydextrose, pectin, chitin,
Water-soluble chitin, chitosan, casein, albumin, soy protein solution, peptone, polyvinyl alcohol, polyacrylamide, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl acetate, polyamino acid, polylactic acid, polymalic acid, polyglycerin, latex, rosin Sizing agent, petroleum resin sizing agent, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide / polyamine resin, polyethyleneimine, polyamine, vegetable gum, polyethylene oxide, hydrophilic crosslinked polymer, polyacrylate, starch poly Acrylic acid copolymer, tamarind gum, gellan gum, pectin, guar gum, colloidal silica and mixtures of one or more thereof.

Further, the water-insoluble substance or the poorly water-soluble substance includes, for example, rice flour, flour, barley flour, rye flour, soy flour, red bean flour, buckwheat flour, bran flour, corn flour, calcium carbonate, clay, talc, glass Fine powder, carbon powder,
Kaolin, calcined kaolin, delamikaolin, heavy calcium carbonate, light calcium carbonate, magnesium carbonate, titanium dioxide, aluminum hydroxide, zinc hydroxide, magnesium hydroxide, calcium hydroxide, magnesium silicate,
For secondary processing of calcium silicate, calcium sulfate, aluminosilicate, silica, sericite, celite, bentonite, smectite, polystyrene fine particles, urea formalin resin fine particles, fine hollow particles, cellulose particles, lauroyl lysine, diatomaceous earth and bacterial cellulose coating Refers to various organic substances and mixtures of one or more thereof.

The above-mentioned third component is selected by those skilled in the art according to the purpose of use of the cellulose of the present invention, in addition to reinforcing the rejuvenating effect of the cellulose by the method of the present invention. A solid component, a low-molecular soluble component, a high-molecular component and the like may be used in combination. For example, when preparing an inorganic powder sheet in the papermaking field, the binding properties of the inorganic powder of BC and the function of the inorganic powder (for example, magnetic powder)
In order to express the above efficiently on the surface of the formed inorganic powder sheet, the cellulose as a raw material is composed of, for example, BC disintegrated material, magnetic inorganic powder, acrylamide (coagulant), and cationized starch (paste). It may be mixed and used at a ratio of about 100: 15: 1: 3. As another example, when used as a gloss enhancer in the food field, xyloglucan,
Salt, sucrose, and the like may be used in combination at a ratio of, for example, 10: 5: 50. In particular, when tasteless, odorless, colorless, and harmless substances are required for use in foods, the third component is preferably an edible soluble polymer. Further, in order to make the surface of the cellulose coating hydrophobic, it is possible to add polystyrene latex or the like as the third component, or to add various drug components as the third component. Those skilled in the art can appropriately select the amount of the third component to be added depending on the type of the substance and the like. Usually, the addition amount of the third component is 2 to the weight of the BC, PCC or MFC.
1,000% by weight. Furthermore, as an example of a bacterial cellulose suspension containing the third component, a culture solution of a cellulose-producing bacterium itself can be used.

The MFC used in the present invention can be obtained by a conventionally known method, for example, crushing and crushing of cellulose fibers such as pulp fibers by a ball mill, pressure crushing in water, crushing in liquid nitrogen, and sonication. Pulverization, or JP-A-56-1
It can be produced by the method described in 00801 or the like.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to Examples, but this does not limit the present invention.

[0025]

【Example】

Example 1 Aeration and agitation culture of cellulose producing bacteria and cellulose
Preparation of BC (1) (1) 750 ml of the BPR2001 strain was charged from a glycerol stock with 100 ml of the following CSL-Fru medium.
1% was inoculated in a volumetric flask and incubated at 28 ° C. for 3 days. After the culture, the roux flask was shaken well to remove the cells from the cellulose membrane, and 12.5 ml of the bacterial solution was inoculated into a 500 ml flask containing 112.5 ml of a medium, and then inoculated at 28 ° C. and 180 rp.
m and cultured for 3 days. Aseptically loosened away by blender Cultures were inoculated and the 60ml in 11 jar charged with CSL-Fru medium 540 ml, a pH in the NH ₃ gas and 1 N H ₂ SO ₄ 4.9~5.1 While controlling
Main culture was performed while automatically controlling the number of revolutions so that the dissolved oxygen amount (DO) became 3.0% or more. After completion, the obtained culture solution was diluted about 5 times with an acetate buffer, and then centrifuged to collect a precipitate. The precipitate was diluted with distilled water to about 8 times the initial culture volume, heated at 80 ° C. for 20 minutes, and collected by centrifugation after heating. The precipitate was suspended in 8 times the amount of 0.1N NaOH and heated at 80 ° C. for 20 minutes to lyse the cells. After lysis, the precipitate was recovered by centrifugation. Thereafter, the precipitate was suspended in an eight-fold amount of distilled water, heated at 80 ° C. for 20 minutes, centrifuged after heating, and the precipitate was collected to wash the cellulose. Purified BC was obtained by performing the same washing three times.

[0026]

[Table 1]

[0027]

Table 2 Vitamin mixture liquid compound mg / L Inositol 200 Niacin 40 Pyridoxine HCl 40 Thiamine HCl 40 Calcium pantothenate 20 Riboflavin 20 p-Aminobenzoic acid 20 Folic acid 0.2 Biotin 0.2

[0028]

TABLE 3 saline mixture _{FeSO 4 · 7H 2 O 360mg /} L CaCl 2 · 2H 2 O 1470mg / L Na 2 MoO 2 · 2H 2 O 242mg / L ZnSO 4 · 7H 2 O 173mg / L MnSO 4 · 5H 2 _{O 139mg / L CuSO 4 · 5H} 2 O 5mg / L

(2) The obtained purified BC was subjected to a defibration treatment under the following conditions. Sonorator (manufactured by SONIC): Disintegration treatment concentration (BC dry weight / volume; the same applies to the concentration of BC suspension).
2%, a liquid temperature of 25 ° C., a flow rate of 6 L / min, a pressure of 50 kg / cm ² , and 1, 2, or 3 passes. The back pressure valve and blade positions were adjusted to maximize sound pressure.

Example 2 Method for Preparing BC Dried Product BC content 25% water content 7 using a freeze-dried product filter press
The BC cake concentrated to 5% was frozen at −20 ° C. and freeze-dried. This was dry-pulverized using a commercially available electric coffee mill. At this time, the water content was 4%. The water content was calculated by measuring a constant weight after drying at 105 ° C. under atmospheric pressure and calculating the value based on wet weight. Dry matter using a drum dryer The above BC cake was dispersed using a stirrer at a rotation speed of 500 rpm to prepare a 2% suspension. This was dried at 120 ° C. using a drum dryer (manufactured by Kusunoki Kikai) to prepare a dried product having a water content of 5%, and then dry-pulverized in the same manner as described above. - in the same manner as dry matter on <br/> SL using a spray dryer to prepare a 1% suspension, using a spray dryer (manufactured by Ohkawara Kakohki), an outlet temperature of 80 ° C. to 9
Drying was performed while adjusting the amount of liquid supplied and the temperature of the input air so that the temperature became 0 ° C., to obtain a dried product having a water content of 4%.

Example 3 Method of Restoring BC from Dried Product 1 part by weight of each of the dried BC samples prepared in Example 2 was mixed with 200 parts by weight of water, and then restoration was attempted by three kinds of shearing methods. . That is, stirring was carried out with a stirrer at 1000 rpm until the dispersion was visually observed, stirring was performed at 18,000 rpm for 2 minutes using a homogenizer with a rotary blade, and stirring for 3 minutes using an ultrasonic crusher. The ultrasonic crushing was performed at the maximum output using an ultrasonic crusher (SONIFIER 450 (manufactured by BRANSON).) All the stirring treatments were performed at room temperature. The viscosity of the polyacrylamide solution measuring system after the stirring was 58 mPa.s, 53 mPa.s and 3 mPa.s, respectively, while the original viscosity was 59 mPa.s. The difference between the viscosity after stirring and the viscosity before stirring is the "degree of shearing" in each of the above-mentioned shearing treatments. The stronger the shearing force involved, the easier the molecular chains were to be broken, and the lower the viscosity.

Example 4 Measurement of Physical Properties The water retention, viscosity and emulsifying effect of the nine kinds of BC samples obtained in Example 3 having different drying methods and restoring methods before drying treatment were measured in accordance with the following measuring methods. With the disaggregation BC as a reference (100%), the restoration rate for each physical property value was determined. Water retention (water retention weight per unit weight of BC) 10 ml of a 0.5% BC suspension was centrifuged (3000 rpm).
, 15 minutes). -Viscosity The viscosity was measured using a B-type viscometer (manufactured by Tokimec) under the conditions of No. 4 rotor, 60 rpm, and 25 ° C. Since the suspension of BC shows thixotropic properties, the measurement was started after the suspension was left overnight, and the value after 3 minutes was used as a representative value of the viscosity.・ Emulsification effect 0.1% BC suspension and salad oil are mixed at a ratio of 1: 1 and emulsified with Fiscotron for 1 minute, and then allowed to stand for 2 days or more.
The ratio of the emulsified layer to the total volume was calculated as a percentage. The results obtained are shown in FIG. In particular, it was found that by performing the ultrasonic treatment with a large degree of shear (for example, 56 mPa.s), the physical properties of the dried product were restored to a level equivalent to or closer to the original level of the disintegrated product (100%). Was.

Example 5 The shearing force of various devices for applying shearing force was measured. Table 4 shows the results.

[0034]

[Table 4] Shearing conditions Viscosity after shearing (mPa.s) Shearing (MPa.s) ─────────────────────────────────── Stock solution (no shear) 59.0 (Viscosity before shearing) 0.0 ─────────────────────────────────── Stirrer, 5 cm φ 4 blades, 1000 rpm 1 minute 56.7 2.3 5 minutes 55.5 3.5 10 minutes 55.1 3.9 ────────── Homogenizer (* 1), with blade, volume 250 ml, 18000 rpm 1 minute 51.9 7.1 5 minutes 23.0 26.0 10 minutes 16.3 42.7 ─── ──────────────────────── ──────── High pressure homogenizer (* 2), 100 kg / cm ² 1 pass 11.2 47.8 2 passes 3.7 55.3 ───────────── ────────────────────── Ultrasonic crusher 1 minute 6.8 52.2 3 minutes 1.3 57.7 ──────── ─────────────────────────── (* 1) Osterizer, (* 2) Rannie mini lab

Example 6 The same experiment as in Examples 2, 3, and 4 was performed using MFC and PCC. Daicel Cellish FD100F was used as the MFC. The PCC used was purified from undried sugar beet pulp in accordance with the method of "CELLULOSE (1996) 3, 183-188". In either case, as in the case of BC, by applying a shearing treatment to increase the degree of shearing and disintegrating, even from a dried product,
A product close to the physical properties of the original wet suspension was obtained.

Example 7 Preparation of Dried Product • Using a dried product filter press using a drum dryer, BC cake concentrated to a BC content of 25% and a water content of 75% was dispersed using a stirrer at a rotation speed of 500 rpm. Then, a suspension having a BC content of 2% was prepared. Carboxymethylcellulose (manufactured by Hanui Chemical) was mixed and dissolved in this suspension so as to be 1/10 of BC. This mixed solution was dried at 120 ° C. using a drum dryer (manufactured by Kusunoki Kikai) to prepare a dried product having a water content of 6%, and further dried by a commercially available electric coffee mill. did. The powder after dry pulverization was sieved using a sieve having an opening of 0.5 mm. -Dried product using a spray dryer Prepare a 1% suspension in the same manner as above, and use a spray dryer (manufactured by Okawara Kakohki Co., Ltd.) to obtain an outlet temperature of 80C or more.
Drying was performed while adjusting the amount of liquid supplied and the temperature of the input air so as to reach 90 ° C., to obtain a dried product having a water content of 4%. Using the same method as in Examples 3 and 4, reconstitution of a dried BC product to a dried product in a wet state and measurement of physical properties were performed. The results are shown in FIG.

[Brief description of the drawings]

FIG. 1 shows the water retention, viscosity and the restoration rate of the emulsifying effect according to the method of the present invention.

FIG. 2 shows the water retention, viscosity, and restoration rate of the emulsifying effect according to the method of the present invention when a third component is contained.

Continuation of the front page (72) Inventor Fumihiro Yoshinaga 3-2-1 Sakado, Takatsu-ku, Kawasaki City, Kanagawa Prefecture Biopolymer Research Inc.

Claims (3)

[Claims] 1. Bacterial cellulose in a dry state,
A method for restoring cellulose, comprising subjecting microfibrillated cellulose or parenchyma cell cellulose to defibration by applying a shearing treatment to increase the degree of shearing. 2. The method according to claim 1, wherein the high shear force is generated by ultrasonic waves. 3. A reconstituted cellulose obtained by the method according to claim 1.