JP2873927B2 - Drying method and dried product of bacterial cellulose - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for drying a cellulosic substance (hereinafter referred to as "bacterial cellulose" or "BC") which can be produced by culturing a cellulosic bacterium, and a dried product obtained by the method. And a method for restoring the dried product.

[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 is characterized in that the cross-sectional width of fibrils (or fine fibers) is about two digits smaller than cellulose produced from wood pulp or the like.
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. .

[0003]

However, when such a disintegrated product of BC is handled in a wet state, a solvent such as water existing several times to several hundred times the weight of the cellulose component is required. In addition, there are various problems such as an increase in storage space, an increase in storage and transportation costs, and decomposition by microorganisms during storage. Therefore, it is expected that if the disintegrated product of BC can be changed from a wet state to a dry state, the above problem will be solved. However, BC consists 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-like microfibers of bacterial cellulose, ordinary cellulose fibers, for example, very thin compared to vegetable pulp fiber, because the surface area is large, so the portion that contributes to hydrogen bonding increases,
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. 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 have problems in various points as described below. still,
Here, "condensed water" refers to swelling by adding water to the dried product.

[0005] First, freeze-drying will be described. In freeze-drying, after a sample is once frozen, drying is performed by sublimation of water molecules from ice while not melting the ice. As is well known, a great deal of energy must be taken when transforming water into ice. At the same time, large energy is also required during the phase change from ice to water vapor during sublimation. To do these things on a large industrial scale requires enormous amounts of energy. Further, if the freezing is performed over a long time in the freezing process, large ice crystals grow. When the water between the fine fibers of the BC is frozen, the growth of ice crystals larger than the voids between the fine fibers causes association of the fine fibers of the BC. Therefore, in order to prevent this phenomenon, it is necessary to rapidly freeze. However, cooling for rapid freezing requires a large amount of energy. Even in consideration of such points, enormous energy is required for industrially performing freeze-drying. Although lyophilization is generally one of the best methods for drying various water-containing samples, such as foods and biological samples, it is not widely used.
Due to the reasons mentioned above.

Next, problems of the solvent replacement method will be described. The gap between the fine fibers of BC is very small,
It is considered that a large amount of water is hydrated on the surface of the fine fibers. Therefore, a large amount of solvent and time are required to replace the solvent. In addition, even when the solvent is replaced with a polar solvent, the surface of the cellulose fine fibers is strongly bonded to each other by hydrogen bonding in the process of drying the solvent due to the moisture present therein. Is difficult to return to the original BC state. Therefore, it is necessary to first dry water after replacing it with a polar solvent such as alcohol, and then finally replace it with a non-polar solvent such as hexane via acetone or the like. In order to carry out these processes industrially,
It requires a large amount of solvent, a lot of time, and dangerous and complicated processes. For the reasons described above, neither the freeze-drying nor the solvent replacement method is satisfactory as a method for drying BC. The present inventors have found that the conventional problems can be solved by adding a third component other than BC and water to an aqueous suspension of BC, followed by drying, and completed the present invention. Was.

[0007]

That is, the present invention provides a method for producing a bacterial cellulose, comprising adding a bacterial cellulose and a third component other than water to an aqueous suspension containing the bacterial cellulose, followed by dehydration drying. Related to the drying method. Furthermore, the present invention also relates to a dried bacterial cellulose obtained by such a drying method. In the method of the present invention, as an example of the hydrophilic liquid used as the third component,
Glycerin, ethylene glycol, dimethylsulfoxide, dimethylformamide, surfactants, lactic acid, gluconic acid and deltagluconolactone and mixtures of one or more thereof can be mentioned. Among them, glycerin is preferred. 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.

[0008] Among these, water-soluble small molecules include, for example, saccharides (glucose, fructose, galactose, xylose, mannose, arabinose, sucrose, lactose, cellobiose, palatinose, maltose, gentiobiose, trehalose, rhamnose, oligosaccharides,
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.

Water-soluble polymers include, 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 or poorly water-soluble substances include, 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,
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 a mixture of one or more thereof.

The third component described above is selected by those skilled in the art according to the intended use of the dried product 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 characteristics between BC and the inorganic powder and the function of the inorganic powder (for example, magnetic powder, etc.) can be improved in the resulting inorganic powder sheet. In order to achieve good expression, the dried product of the present invention, which is a raw material, comprises BC disintegrated product, magnetic inorganic powder, acrylamide (coagulant), and cationized starch (paste), for example, 100: 15: 1: 3. What was mixed and dried at an approximate ratio may be used. As another example, when used as a thickener in the food field, xyloglucan, salt, sucrose, and the like, for example, 10
They may be used in combination at a ratio of 0: 5: 20. In particular, when tasteless, odorless, colorless, and harmless substances are required for use in foods, the third component is preferably an edible soluble polymer. For example, by using a mixed feed for cultured fish as the third component, the dried bacterial cellulose of the present invention is useful as a moist pellet feed for cultured fish containing bacterial cellulose as a binder, or as a dog food or a cat food. Can be obtained. The addition amount of these third components can be appropriately selected by those skilled in the art according to the type of the substance and the like, and is usually 2 to 1,000% by weight based on the weight of BC. Further, as an example of the bacterial cellulose aqueous suspension containing the third component, a culture solution of a cellulose-producing bacterium itself or a suspension containing the third component described above can also be used. In particular, as described above, when the dried bacterial cellulose of the present invention is used as various feeds, the cells themselves are also contained in the obtained product, and the nutritive value of the feed is increased. Is expected.

The dehydration drying method in the method of the present invention may be any conventionally known method, and examples thereof include spray drying, pressing, air drying, hot air drying, and vacuum drying. Examples of the drying apparatus specifically used in the method of the present invention are as follows. That is, continuous tunnel dryer, band dryer, vertical dryer,
Vertical turbo dryer, multi-stage disk dryer, through-air dryer, rotary dryer, flash dryer, spray dryer, cylindrical dryer, drum dryer, screw conveyor dryer, rotary dryer with heating tube, vibration transport Batch type box type drying device, through-air drying device, vacuum box type drying device, drying device, etc.
And a drying device such as a stirring drying device 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 the drying include direct heating, radiant heating, and indirect heating, and among them, infrared heating, microwave heating, and the like are particularly desirable from the viewpoint of energy efficiency.

By using the above-described apparatus, BC can be dried to a state where it can be restored to the original wet state. In addition, in this specification, a "dry" state is not a completely dry state in which there is no water contained in a 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 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,
In the case of low molecular weight, because of the action of retaining water in the form of water of crystallization or the like, the method described above, even if a dried product seemingly dried by performing drying with the device When left in normal air, water vapor in the air is adsorbed to reach an equilibrium state. If you need to save,
It is necessary that the water activity value of the dried product of the present invention is not more than the extent that microorganisms cannot grow. A water activity value of at most 0.9 or less, desirably 0.75 or less is required.

In the method of the present invention, it is preferable that the cellulosic material has been subjected to a defibration treatment. The disintegration phenomenon of bacterial 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 disaggregation treatment of bacterial cellulose can be performed by applying a mechanical external force to bacterial cellulose. Further, the disintegration treatment can also be performed by acid hydrolysis, hydrolysis using an enzyme, and a bleaching agent. 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 actually applying these mechanical external forces to bacterial cellulose, for example, it can be achieved by using a mixer, a polytron, an ultrasonic oscillator, or the like.

In the disaggregation process using a mixer, the mechanical external force is mainly composed of an impact force caused by collision of the stirring blade with bacterial cellulose and a shear force generated by a displacement phenomenon due to a difference in speed of the medium. In the disaggregation process using Polytron, the mechanical external force is the compressive force of bacterial cellulose sandwiched between the external teeth and the internal teeth, the impact force of the collision of high-speed rotating teeth with bacterial cellulose, the static external teeth and the high speed of stationary external teeth. The shear stress generated in the medium existing in the gap between the rotating internal teeth is mainly involved. 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-mentioned specific examples as long as a certain load (mechanical external force) can be applied to the bacterial cellulose. Other disaggregation treatment conditions can be appropriately selected by those skilled in the art.

Although the defibration treatment has been described above, the defibration treatment according to the present invention is carried out after stirring and culturing 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 the bacterial cellulose, and in the stirring culture, the bacterial cellulose can be sufficiently disaggregated by the stirring action for the purpose of culture. Further, the same can be said for the operation of separating, washing, purifying and transporting bacterial cellulose obtained by stirring culture, and additional disaggregation treatment in these operations is also included in the disaggregation treatment of the present invention. Please note.

[0017] The stirring culture referred to in the present invention is a culture method in which a culture solution is stirred while being stirred, and the structure of bacterial cellulose, for example, the crystallization index is reduced due to the stirring effect during the stirring culture. It changes so that the crystal part increases. 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. Examples of the culture operation method include 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 cellulose-producing bacterium that produces BC used in the present invention is, for example, Acetobacter xylinum subsp. Saccharumentans ( Acetobacter xylinum subsp. S) represented by BPR2001 strain.
ucrofermentans ), Acetobacter xylinum ( Acet)
bacterium xylinum ) ATCC 23768, Acetobacter xylinum ATCC 23969, Acetobacter
Pasteurianus ( A. pasteurianus ) ATCC1024
5, Acetobacter xylinum ATCC 14851,
Acetic acid bacteria (genus Acetobacter) such as Acetobacter xylinum ATCC11142 and Acetobacter xylinum ATCC10821, and others, Agrobacterium, Rhizobium, Sarsina, Pseudomonas,
The genera are Achromobacter, Alcaligenes, Aerobacterium, Azotobacter and Zooglare, and various mutants created by subjecting them to mutation treatment by a known method using NTG (nitrosoguanidine) or the like. The BPR2001 strain was deposited on February 24, 1993 at the Patent Microorganisms Depositary Center of the Institute of Biotechnology and Industrial Technology, Ministry of International Trade and Industry (accession number FERM P-
13466) and subsequently transferred to a deposit under the Budapest Treaty on the International Recognition of Patent Deposits on February 7, 1994 (accession number FERM BP-4545).

A chemical mutation treatment method using a mutagen such as NTG includes, for example, Bio Factors, Vol. 1, p. 297-302.
(1988) and J. Gen. Microbiol, Vol. 135, p. 2917-2.
929 (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. Among the cellulose-producing bacteria created by the above-mentioned method, a high polymerization degree having a weight average polymerization degree of not less than 1.6 × 10 ⁴ , preferably 1.7 × 10 ⁴ or more in terms of polystyrene is obtained by aeration and stirring culture. Or a strain that produces bacterial cellulose having a high degree of polymerization having a weight-average degree of polymerization in terms of polystyrene of 2.0 × 10 ⁴ or more by producing the bacterial cellulose or by culturing it in a static state. Among the bacterial strains producing bacterial cellulose having a high degree of polymerization that can be used in the present invention, BPR
3001A was deposited on June 12, 1995 at the Patented Microorganisms Depositary Center of the Institute of Biotechnology and Industrial Technology, Ministry of International Trade and Industry, and has been 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, various products obtained using high polymerization degree bacterial cellulose as a raw material have higher strength and elasticity than those obtained using relatively low polymerization degree bacterial cellulose as a raw material. High rate. Therefore, when it is desired to produce a product having a high strength and an elastic modulus, 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 medium used in the stirring culture of the present invention, sucrose, glucose, fructose, mannitol, sorbitol, galactose,
Maltose, erythrit, glycerin, ethylene glycol, ethanol and the like can be used alone or in combination. Furthermore, starch hydrolyzate containing these, citrus molasses, beet molasses, beet juice,
Sugar cane juice, fruit juices such as citrus fruits, and the like can be used in addition to sucrose. Further, as a nitrogen source, an organic or inorganic nitrogen source such as ammonium salts such as ammonium sulfate, ammonium chloride, and ammonium phosphate, nitrate, and urea can be used.
-Nitrogen-containing natural nutrients such as Peptone, Bacto-Soytone, Yeast-Extract, and Tono may be used. Amino acids, vitamins, fatty acids, nucleic acids, 2,7,9 as organic micronutrients
-Tricarboxy-1H pyrrolo [2,3,5] -quinoline-4,5-dione, sulphite pulp waste liquor, ligninsulfonic acid and the like may be added.

When an auxotrophic mutant that requires amino acids or the like for growth is used, it is necessary to supplement the required nutrients. 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.

The bacterial cellulose of the present invention can be produced, for example, by the following method. Bacterial cellulose obtained by aeration and stirring culture is separated from the culture solution by a centrifugation method, a filtration method, or the like. The bacterial cells produced by the method of the present invention may be recovered as they are, or may be subjected to a treatment for removing impurities other than the cellulosic substance containing the bacterial cells contained in the substance. 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.

The dried bacterial cellulose obtained by the method of the present invention can be restored to its original wet state by dispersing it again in water and mixing with stirring. Further, before or after the stirring and mixing operation, appropriate heat treatment can be performed, and the heat treatment may promote restoration. Further, by performing the above-described defibration treatment at the time of the stirring and mixing, more preferable restoration can be performed. When the dried bacterial cellulose obtained by the method of the present invention is condensed and restored to the original state of the disintegrated product, the cellulose fine fibers constituting the BC become in a state where they are not firmly bound to each other. . As mentioned earlier, BC
Consists of very fine cellulose fine fibers. As described in the present invention, when restored to the original disintegrated state, a large amount (cellulose fine fiber) is formed on the surface of such fine fibers or in a void having a network structure composed of fine fibers. (Several times to several hundred times the weight of the liquid). Since such a state containing a large amount of liquid components is obtained, those having good dispersibility, sedimentation properties, liquid viscosity, and the like can be obtained. On the other hand, irrespective of the method of the present invention, as previously known, such a state is restored by simply adding water to a dried product obtained by simply drying a disintegrated product of BC or the like. It is not possible.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of examples, but the examples do not limit the present invention. In addition, in each Example, various characteristic values were measured as follows. The dispersibility of the dispersible suspension was visually compared with the disintegrated product before drying. The method of measuring the degree of sedimentation of the suspension was as follows: 10 ml of a 0.2% bacterial cellulose (BC) suspension was
After being centrifuged at 3000 rpm for 15 minutes in a 1 l tube, the volume of the sedimented portion was represented by the ratio to the total volume. The larger the value of the degree of sedimentation, the harder the sedimentation, and the more dispersed the particles. The value of the sedimentation degree recovery ratio (the sedimentation degree of the disaggregated matter after drying and condensate / the sedimentation degree of the disaggregated matter before drying) was used. Viscosity The viscosity in the present invention means the absolute value of the complex viscosity at 30 ° C. and an angular velocity of 10 rad / sec when an aqueous suspension having a BC content of 0.1% is measured by a dynamic liquid viscoelasticity measurement method.
Value (hereinafter simply referred to as “viscosity”). More specifically, dynamic liquid viscoelasticity measuring apparatus (Rheometrics
FLUIDS SPECTROMETER R
FS II ", 2 ml of an aqueous suspension of 0.1% concentration of BC disintegration was placed between parallel rotating disks having a diameter of 5 cm, and the angular velocity was 1 to 100 rad / sec at a temperature of 30 ° C.
10 rad / sec strain 1 when changed to
Viscosity measured at 0%.

[0027]

【Example】

Example 1 Production and Disintegration of Bacterial Cellulose (1) Preparation of Seed Bacterial Solution (Proliferation of Microorganisms) Cellulose-producing microbes were multiplied by a flask culture method. Basic composition of 40 g / L fructose, 1.0 g / L potassium phosphate, 0.3 g / L magnesium sulfate, 3 g / L ammonium sulfate, 5 g / L bacto-peptone, 1.4 ml / L lactic acid, initial pH 5.0 Medium 100
BPR into a 750 ml Roux flask into which the
1 ml of a cryopreserved bacterial solution of the 2001 strain (FERM BP-4545) was inoculated, and statically cultured at 28 ° C. for 3 days in a constant temperature incubator. After the seed culturing, the Roux flask was shaken well, and the contents were subjected to gauze filtration under aseptic conditions to obtain a seed bacterial solution.

(2) Production of Bacterial Cellulose by Stirring Culture 60 ml of the above-mentioned seed bacterial solution is aseptically inoculated into a sterilized small jar fermenter (total volume: 1000 ml) into which 540 ml of a stirring culture medium to be described later has been sterilized. 20 at 30 ° C
PH for 1 hour or 30 hours with 1N NaOH or 1N H
While controlling to 5.0 with ₂ SO ₄ , the stirring speed was initially 400 rpm, and the dissolved oxygen (DO) was 3.0.
Stirring culture was performed with a jar fermenter while automatically controlling the number of revolutions so as to fall within 0 to 21.0%. For the stirring culture, a medium having the following composition was used. Fructose 40 g / L, KH ₂ PO ₄ 1.0 g / L, MgSO ₄ 0.3 g / L, (NH ₄ ) ₂ SO ₄ 3 g / L, Bacto-Soytone (manufactured by Difco) 5 g / L and sono (soybean) 5 g / L Initial pH 5.0 After cultivation, the solids in the jar fermenter were collected, washed with water to remove the medium components, and then placed in a 1% NaOH aqueous solution at 110 ° C. The cells were removed by treatment for 20 minutes. Further, the produced cellulose was washed with water until the washing liquid became nearly neutral to obtain bacterial cellulose.

(3) Agitation culture with addition of carboxymethylcellulose In the agitation culture described in (2),
Furthermore, carboxymethylcellulose was added at 5 g / l for culturing. The resulting culture was more viscous than the culture obtained in (2). (4) Production of Bacterial Cellulose (Comparative Example) by Static Culture 600 ml of a medium having the composition described in (2) was dispensed into a sterile petri dish by 30 ml each, and allowed to stand at 30 ° C. for 7 days. did. After completion of the culture, the bacterial cellulose formed on the surface of the Petri dish was washed with water to remove the medium components.

(5) Disintegration of Bacterial Cellulose Water was added to the washed bacterial cellulose obtained by the stirring culture method of (2) to obtain a suspension having a disintegration concentration of about 0.2% by weight (dry weight / volume of bacterial cellulose). A suspension was prepared. Similarly, water was added to the bacterial cellulose obtained by the stationary culture in (4) to prepare a suspension having a disintegration treatment concentration of about 0.2% by weight (dry weight / volume of bacterial cellulose). Next, these suspensions were disintegrated for 3 minutes at 25 ° C. using a stirrer (Blender manufactured by Auster). The rotation speed of the stirrer was set to the highest level. By this disaggregation treatment, a BC disintegration product (A) was obtained from the stirring culture, and a BC disintegration product (B) was obtained from the stationary culture. Water was added to the culture solution in the jar fermenter containing bacterial cellulose after completion of the stirring culture in (2) and (3) to adjust the bacterial cellulose content to 0.2%. Then, the mixture was stirred at 25 ° C. for 3
Disintegrated for minutes. The rotation speed of the stirrer was set to the highest level. By this disaggregation treatment, BC disaggregates (C) and (D) were prepared from the dilutions of the respective culture solutions. In addition,
The concentration of BC in the above was determined by centrifuging to remove a wet solid from the culture solution, and then in a 0.2 N sodium hydroxide solution (20 times the solid content) at 100 ° C.
After immersion for a time to remove bacterial cells and medium components other than bacterial cellulose, the cells were sufficiently washed and dried and calculated from the measured dry weight.

Example 2 2 L of a liquid obtained by adding sedimentable light calcium carbonate to the disintegrated product (A) prepared in Example 1 was mixed for 15 minutes using a pulp disintegrator (manufactured by Kumagaya Riki Kogyo Co., Ltd.). The amount of calcium carbonate added is 0.1% based on the amount of BC contained in the defibrated material.
1, 5, 50 and 500 times. Place a portion of the mixture in a 100 cm ² container to a depth of 2 cm
Dry at 0 ° C. under normal pressure. Drying took 48 hours. The shape of the dried product obtained after drying was plate-like. After 200 ml of water was added to the plate-like dried product and left for 3 minutes, the mixture was stirred for 2 minutes and 30 seconds using a medicine spoon. The state of dispersion of the disintegrated material of the mixture obtained after stirring was observed. Table 1 shows the results.

[0032]

[Table 1] X: The dispersion state of BC is not observed. Δ: Partial aggregation and sticking of BC are observed. ：: A dispersion state similar to the dispersion state of the disintegrated product before drying.

It was found that when calcium carbonate was added 5 times or more to the BC in the deflocculated product, the dispersed state of the deflocculated product was restored to the state before drying when water was recovered after drying. Further, when added 50 times or more, good recovery of the dispersed state was observed when added. The same test was further performed using the disintegrated products (C) and (D) prepared in Example 1 instead of the disintegrated product (A). As a result, the same effect as that of the disintegrated product (A) was obtained. Further, the mixed solution was heat-treated. The heat treatment was performed at 120 ° C. for 20 minutes using a pressure steam sterilizer. After the heat treatment, the mixture was cooled to room temperature, and the dispersion state of the mixture was observed.
Table 2 shows the results.

[0034]

[Table 2] X: The dispersion state of BC is not observed. Δ: Partial aggregation and sticking of BC are observed. ：: A dispersion state similar to the dispersion state of the disintegrated product before drying.

As compared with the case where no heat treatment was performed (Table 1), it was found that the heat treatment improved the dispersion state in the system to which 5 times the amount of calcium carbonate was added. A similar experiment (condensation after drying and heat treatment after condensing) was also performed on the disintegrated product (B). As a result, in a system in which calcium carbonate was added at least 5 times the amount of BC,
It was confirmed that the dispersed state was recovered by condensing water after drying.

Example 3 2 L of a liquid obtained by adding sedimentable light calcium carbonate to the disintegrated product (B) prepared in Example 1 was mixed for 15 minutes using a pulp disintegrator (manufactured by Kumagaya Riki Kogyo Co., Ltd.). The amount of calcium carbonate added is 0.1% based on the amount of BC contained in the defibrated material.
1, 5, 50 and 500 times. A part of the mixture was filtered through a 200-mesh plain weave mesh made of polyethylene terephthalate. The filtration area was about 150 cm ² . After several tens of minutes, when almost no liquid came from the lower surface of the filtration mesh, a 200-mesh polyethylene terephthalate plain weave mesh was placed on the wet mat formed on the upper surface of the filtration mesh. , And a pressure of about 20 g / cm ² was applied for 15 minutes to squeeze out the moisture of the wet mat. After pressing and dewatering, the wet mat was taken out, sandwiched between stainless steel 100 mesh nets from above and below, and further sandwiched between stainless steel plates having a thickness of 3 mm, and then pressed and dried at 150 ° C. for 7 minutes. The pressing pressure was 400 g / cm ² . The shape of the dried product obtained by pressing and drying was a thin film or a cracked flake. To this dried product, the same amount of water as before filtration was added, and the mixture was allowed to stand for 10 minutes, and then stirred for 300 seconds using a spoon. The state of dispersion of the disintegrated material of the mixture obtained after stirring was observed. Table 3 shows the results.

[0037]

[Table 3] X: The dispersion state of BC is not observed. Δ: Partial aggregation and sticking of BC are observed. ：: A dispersion state similar to the dispersion state of the disintegrated product before drying.

The dried product obtained by squeezing and drying without addition of calcium carbonate or by adding 0.1 times calcium carbonate had the same shape even after condensed water. It was found that when more than 5 times the amount of BC was added, the dispersed state of the disintegrated material was restored to the state before drying when water was returned after drying. Further, when added 50 times or more, good recovery of the dispersed state was observed. Further, the mixed solution was heat-treated. The heat treatment was performed at 120 ° C. for 20 minutes using a pressure steam sterilizer. After the heat treatment, the mixture was cooled to room temperature, and the dispersion state of the mixture was observed. Table 4 shows the results.

[0039]

[Table 4] X: The dispersion state of BC is not observed. Δ: Partial aggregation and sticking of BC are observed. ：: A dispersion state similar to the dispersion state of the disintegrated product before drying.

As compared with the case where no heat treatment was performed (Table 3), it was found that the heat treatment improved the dispersion state in a system to which calcium carbonate was added in an amount of 5 times or more.

Example 4 Glycerin was added to the disaggregated products (A) and (B) prepared in Example 1 to prepare a mixed solution. The amount of glycerin to be added is 0, based on the weight of BC contained in the defibrated product.
2, 10, 50, 100, 150, and 200%.
100 ml of each mixture was dried at 100 ° C. to constant weight. After drying, cool to 4 ° C. and add distilled water to 100
ml was added and the mixture was allowed to stand for 15 minutes. After standing, these liquids were stirred and mixed for 20 seconds using a pencil mixer (manufactured by Inuchi Seieido) . The state of dispersion of the disaggregated product after stirring and mixing was visually observed. A heat treatment was performed at 100 ° C. for 1 hour before stirring and mixing, and then the mixture subjected to stirring and mixing was similarly visually observed for the state of dispersion of the disintegrated product. Table 5 with the results
Shown in

[0042]

[Table 5] Addition amount of glycerin during drying and dispersion state of disintegrated product after condensate after drying (visual observation)量 Addition amount of glycerin After drying, add water and after drying, add water and then heat (%, relative to BC weight). (A) (B) (A) (B) 離0 (no addition) × × × × 2 △ △ ○ ○ 10 △ △ ○ ○ 50 ○ ○ ○ ○ 100 ○ ○ ○ ○ 150 ○ ○ ○ ○ 200 ○ ○ ○ ○ ─────────── ──────────────────────── ×: The dispersion state of BC is not observed. Δ: Partial aggregation and sticking of BC are observed. ：: A dispersion state similar to the dispersion state of the disintegrated product before drying.

(A) and (B) in the table correspond to the disintegration products (A) and (B) prepared in Example 1, respectively. In a system in which glycerin was added at 2% or more of BC, it was found that when water was added after drying, the dispersed state of BC was recovered.

Example 5 The viscosities of deflocculants containing various concentrations of glycerin prepared in Example 4 were compared before and after drying and condensate heat treatment. However, the sample used in the experiment was only the disintegration product (A). Rheome, a dynamic liquid viscoelasticity measuring device, is used for measuring the viscosity.
A 2 ml sample was sandwiched between parallel rotating disks having a diameter of 5 cm using an apparatus manufactured by Trics, and an angular velocity of 10 rad / sec.
The viscosity at a temperature of 30 ° C. when the disk was vibrated at a strain of 10% was measured. The concentration of BC contained in the sample was adjusted to 0.1% by adding distilled water. Table 6 below shows the measurement results.

[0045]

[Table 6] Glycerin addition amount Disintegration viscosity (P) Viscosity restoration Rate (%, relative to BC weight) Before drying After drying, condensing, heat treatment (%) ────────────────────────────── ０ 0 (no addition) 10.4 0.06 5.7 2 10.5 2.4 22.9 10 9.9 2.5 25.3 20 9.2 2.6 28.3 100 9.0 3.2 35.6 150 8.5 3.9 45.9 200 7.2 4.5 62.5 500 6.9 5.5 79.9 ────────────────────────

The viscosity recovery rate in Table 6 is a percentage obtained by dividing the viscosity of the deflocculated product after the heat treatment for drying and condensing by the viscosity of the deflocculated product before drying. In the absence of any additives, the viscosity of the deflocculated product after condensed water was about 6% or less before drying, indicating that the properties of the original deflocculated product were lost by drying. However, it was found that by adding glycerin and drying, the properties of the disintegrated product were maintained to some extent after condensing.

Example 6 The sample of Example 5 was measured for the degree of sedimentation. The method of measuring the degree of sedimentation was described as the ratio of the volume of the sediment to the total volume after 10 ml of the disintegrated product was placed in a 15 ml tube made of Falcon and centrifuged at 3000 rpm for 15 minutes. Table 7 shows the results.

[0048]

[Table 7] Glycerin added amount Disintegration sedimentation degree (%) Sedimentation Restoration rate (%, relative to BC weight) Before drying After drying, condensing, and heat treatment (%) ──────────────────────────── ０ 0 (no addition) 37.0 5.0 13.5 2 39.0 16.0 41.0 10 39.0 16.0 41.0 20 40.0 18.0 40. 5 100 41.0 27.0 65.9 150 41.0 29.0 70.7 200 42.0 33.0 78.6 ────────────────

The sedimentation degree recovery rate in Table 7 is a percentage obtained by dividing the sedimentation degree of the deflocculated product after the drying condensate heat treatment by the sedimentation degree of the deflocculated product before drying.

Example 7 To 50 ml of the disintegrated product (A) having a BC content of 0.2% prepared in Example 1, 0.1, 10, 10
50 and 250 mg were dissolved. Dispersibility, sedimentation degree, and viscosity were measured as disintegration properties of these mixed liquids. The sample was dried at 50 ° C. for 5 hours and at 80 ° C. for 2 hours for a total of 7 hours, and then dried at 105 ° C. until the appearance of the sample became a sheet and became almost constant. Table 8 shows the results.

[0051]

[Table 8] X: The dispersion state of BC is not observed. Δ: Partial aggregation and sticking of BC are observed. ：: A dispersion state similar to the dispersion state of the disintegrated product before drying.

When no addition was made, the properties of the deflocculated product were lost due to the drying step, but when 10 mg or more of carboxymethylcellulose was added, the deflocculated product such as dispersibility and viscosity even after the drying step was added. It was found that the characteristics of the above were considerably retained.

Example 8 After the disintegrated product (A) prepared in Example 1 was concentrated using a centrifuge, distilled water was added to obtain a disintegrated product having a concentration of 1%.
After mixing 20 parts of the disintegrated product and 80 parts of the various solutions shown in Table 7, the mixture was dried. After drying, 100 parts of water at 80 ° C. was added, the mixture was allowed to stand at 80 ° C. for 30 minutes, and then stirred using a pencil mixer. The dispersibility and the degree of sedimentation of the obtained mixture were evaluated at room temperature. As a comparative object, only the disintegration product (A) was used. The drying conditions were as follows: after drying using a far-infrared ray drying device for 50 minutes,
It dried under reduced pressure for hours.

[0054]

[Table 9] Type and concentration of various solutions mixed with the disintegration product (unit is w / v%) ────── Additives Additive concentration (%) グ ル コ ー ス Glucose 0.25 , 2.0, 5.0 fructose 0.25, 2.0, 5.0 galactose 0.3 xylose 0.2 mannose 0.2 arabinose 0.2 sucrose 0.2, 2.0, 20.0 lactose 0.3 cellobiose 0.4, 0.8 palatinose 2, 10 maltose 0.2, 2.0, 10.0 trehalose 0.1, 0.5 rhamnose 1.0 sorbitol 0.2, 0.5, 1. 0 Erythritol 1.0 Maltitol 0.2, 0.25, 0.5, 1.0 Liquid sugar (concentration is solid Conversion) 0.25,0.5,1.0,5.0 ─────────────────────────────────

In the case of no addition, the properties of the disintegrated product were lost in the drying step. However, in all cases where the substances shown in Table 9 above were added, the properties of the defibrated product were improved after condensate. That is, as a result of the visual observation, a good dispersion state is obtained, and the above-mentioned sedimentation degree restoration rates are all 25.
% Or more.

Example 9 The disintegrated product (A) prepared in Example 1 was concentrated using a centrifuge, and distilled water was added to obtain a disintegrated product having a concentration of 1%.
A total of 80 parts of this disaggregated product, a dextrin solution, a xanthan gum solution, a xyloglucan solution, a soluble starch solution, a carboxymethyl cellulose solution, and / or a glycerin solution were mixed and dried. The soluble starch solution was prepared from a suspension obtained by suspending soluble starch manufactured by Junsei Chemical in water and then gelatinizing the suspension by heating. After drying, 100 parts of water at 80 ° C. was added, the mixture was allowed to stand at 80 ° C. for 30 minutes, and then stirred using a pencil mixer. The dispersibility and the degree of sedimentation of the obtained mixture were evaluated at room temperature. As a comparative object, only the disintegration product (A) was used. The drying was performed at 105 ° C. for 2 hours after air drying at 70 ° C. overnight. For some, viscosity measurements were also performed. Table 10 shows the additives and concentrations.

[0057]

[Table 10]

100 ml of a mixture sample having the composition shown in Table 10 was added to 80
After drying at ℃ for 24 hours, it was further dried at 105 ° C. for 30 minutes using infrared rays. 100 ml of tap water is added to the obtained dried product.
After the addition, the mixture was stirred with a magnetic stirrer for 1 hour. Thereafter, autoclave sterilization was performed at 120 ° C. for 20 minutes. After leaving the autoclave and cooling at room temperature, the properties of the defibrated product were evaluated. Table 11 shows the results.

[0059]

[Table 11]

It was found that, when the additive was added and dried, the properties as a disintegrated product in terms of dispersibility, sedimentation degree, viscosity, etc. were not lost even after the drying step.

Example 10 1 L of the disintegrated product (A) prepared in Example 1 was mixed with rice flour (fraction obtained by dry-grinding rice and passing through a 200-mesh sieve),
Wheat flour, soybean flour, buckwheat flour, pulverized wheat bran (fraction that has been dry-pulverized and passed through an 80-mesh sieve), corn flour, activated carbon, talc, kaolin, calcined kaolin,
Titanium dioxide, aluminum hydroxide, celite, bentonite, silica, lyophilized colloidal chitin powder (colloidal chitin is freeze-dried, then wet-ground in ethyl ether and then dried), polystyrene latex (average particle size 10 μm), diatomaceous earth, Avicel 98g of one of them
Add and mix well. Each mixture was dried at 80 ° C. at normal pressure for 48 hours and under reduced pressure for 48 hours. 1L after drying
Of water and keeping the temperature at 50 ° C. while stirring with a stirrer.
The mixture was stirred at 00 to 400 rpm for 3 hours. After stirring, the dispersibility of BC in the mixture was visually evaluated with a polarizing optical microscope. In addition, the degree of sedimentation was measured using a part of each mixed solution. When dried without adding anything to the disintegrated product (A), the dispersibility is deteriorated even when hot water is added and stirred, and the properties of the disintegrated product are lost by drying. When dried, the dispersibility after condensing was good, and the sedimentation degree restoration rates were all 33% or more.

Example 11 To 50 ml of the disaggregated product (A) prepared in Example 1, 0.2 g of sodium sulfate, 0.5 g of sodium chloride or 0.2 g of sodium bicarbonate were mixed using a magnetic stirrer. These mixed liquids were dried using a far-infrared ray drying device until the respective weights became 1 g or less, to obtain semi-dried products. These semi-dried products were placed in a batch type microwave heating device and dried while ventilating to obtain dried products having a water content of 1% or less. After each dried product was powdered in a mortar, 2.4 ml of water was added and kneaded. Then, water was added with stirring to make the final liquid volume 50 ml. These liquids were heat-treated at 120 ° C. for 30 minutes using an autoclave. When evaluating these dispersibility and sedimentation degree restoration rate,
As compared to the case where no additive was added, the dispersibility was good in all cases, and the sedimentation degree restoration rate showed a good value of 25 to 50%. Table 12 shows the results.

[0063]

[Table 12] 添加 Additives Dispersibility ^{* 1} Restoration rate of sedimentation degree (%) ─────ナ ト リ ウ ム Sodium sulfate 43.4 Salt ○ 29.1 Sodium bicarbonate ３ 30.0 No addition × 13.6 ─────────────────────── ───────────────────────── * 1 Dispersibility when compared with the dispersibility before drying (○: same dispersibility as before drying, ×: The dispersibility before drying is not restored)

Example 12 One liter of the disintegrated product (A) prepared in Example 1 was concentrated using a centrifugal separator to obtain a cake composed of 35 g of wet weight disintegrated material. This cake was added to 100 ml of 2% dextrin, sufficiently stirred, and mixed by suspension. This solution was placed in a polypropylene container until the depth became about 1 cm, and then dried at 105 ° C. After drying, a sheet-like substance was obtained. 2 g of this sheet-like substance was taken and the particle size was 4 using a dry pulverizer.
The powder was pulverized until it became not more than 00 μm. The properties of the sheet-like material and the powder were compared. First, the bulk density was measured. The bulk density of each was calculated according to the following equation. Bulk density of sheet-like substance = weight of sheet-like substance / (area of sheet-like substance × thickness of sheet-like substance) A caliper was used for measuring the thickness. Bulk density of powder = weight of powder / volume of powder The volume measurement of the powder was performed by putting the prepared powder in a beaker.

After evaluating the bulk density, water was finally added to the sheet material and powder having a BC concentration of 0.2%. These mixed liquids were stirred with a magnetic stirrer for 10 minutes to prepare a disintegration solution. The time required for dissolution at the time of solution preparation, and the solubility, dispersibility, sedimentation restoration rate, and viscosity restoration rate of these solutions were evaluated. The results are shown in Table 13 together with the evaluation results of the bulk density.

[0066]

[Table 13] Characteristics of sheet material and powder ────────────────────────── Shape before condensate Sheet material powder 物質────────────────────── Bulk density (g / cm ³ ) 1.0 0.59 Dissolution time ^{* 1} (sec) 240 30 Dispersibility ○ ○ Sedimentation Degree of recovery (%) 99 107 Viscosity recovery rate (%) 102 100 ────────────────────────── * 1 The time was taken until no large mass was observed with the naked eye.

By making the dried product into a powder, the time required for condensing water can be reduced. In addition, it was found that the sheet-like material had a large bulk density and was advantageous during storage.

Example 13 1 L of the disintegrated product (A) prepared in Example 1 was concentrated using a centrifugal separator to obtain a cake consisting of 35 g of wet weight disintegrated material. This cake was added to 100 ml of a 2% dextrin solution or 100 ml of a 1% carboxymethylcellulose solution, sufficiently stirred, and mixed by suspension. After placing this solution in a polypropylene container until it is about 1 cm deep, 10
Dried at 5 ° C. After drying, a sheet-like substance was obtained.
Water was added to the sheet material so that the BC concentration was 0.1%, and the mixture was stirred and mixed well, and then autoclaved at 120 ° C. for 20 minutes. After cooling to room temperature, the flow curve was measured using a dynamic viscoelasticity measuring device (manufactured by Rheometrics). These results were compared with a liquid obtained by diluting the disintegrated product (A) before drying twice with distilled water. The results are shown in FIG. The product dried with dextrin showed a flow curve almost similar to the disintegrated product before drying. That is, it was a value having a yield value. On the contrary,
It was confirmed that when carboxymethylcellulose was added, the yield value was almost zero, and the apparent viscosity was significantly lower than that of the disintegrated product before drying.

Example 14 The disintegrated product (A) prepared in Example 1 was filtered and concentrated using three 400-mesh nets made of polyethylene terephthalate. Water was removed from the concentrate using a shake-off centrifuge to obtain a cake having a solid content of 6.1%. For 10 parts of this cake, dextrin 5
, 2 parts of xanthan gum and 1 part of sucrose were added and mixed well. Next, the mixture was pressed between two stainless plates until the thickness became about 1 to 2 mm. The temperature during the press was 75 ° C. The resulting plate-like cake is placed on a 10 mesh stainless steel mesh,
And dried at 105 ° C. for 2 hours under normal pressure.
The dried plate obtained after drying was cut into about 3 mm squares using scissors, and then water was added so that the BC concentration became 0.2%, followed by stirring at 30 ° C. for 50 minutes. Stirring is 40
At a stirring speed of 0 rpm, a portal type stirring blade was used.
The inner diameter of the stirring tank was set to 1.7 times the diameter of the stirring blade. After the stirring, a uniform suspension (referred to as suspension (a)) in which no solid particles were observed by visual observation was obtained. The dispersibility of this suspension (a) and the degree of sedimentation restoration were measured. Next, the suspension (a) was disaggregated using a blender. Disintegration condition is 18000 rpm using a blade
This was performed for 3 minutes at 25 ° C. to obtain a defibrated suspension (referred to as suspension (b)). The dispersion state of the suspension (b) and the degree of sedimentation restoration were measured. The measurement of the dispersibility and the degree of sedimentation restoration was performed after deaeration under vacuum to sufficiently remove bubbles in the suspension. Table 14 shows the results.

[0070]

Table 14 Properties of suspensions (a) and (b) 懸濁液 Suspension (a) Suspension Liquid (b) ────────────────────────── Dispersibility ○ ○ Sedimentation restoration rate (%) 80 100 ─────── ───────────────────

It has been found that disaggregation after condensate promotes restoration of characteristics after drying.

Example 15 A mixture was prepared by mixing the disintegrated product (A) prepared in Example 1 with an additive having the composition shown in Table 15. The concentration of each deflocculated product contained in this mixture was 0.2% by weight. Thereafter, spray drying (spray drying) was performed.
Using SPRAY DRYER DL41 manufactured by Yamato Scientific Co., Ltd. as a spray dryer, the conditions were as follows: inlet temperature 270 ° C, outlet temperature 90 ° C,
The mixed liquid flow rate is 20 ml / min, and the air flow rate is 600-70 / min.
It was set at 0 liters. The shape of the obtained dried product was observed. Water was added to the powder so that the BC concentration became 0.2%, and the mixture was stirred for 10 minutes using a magnetic stirrer to prepare a solution. These solutions were evaluated for dispersibility, sedimentation degree, and sedimentation degree restoration rate. Table 16 shows the results.

[0073]

[Table 15] ───────────────────────────── No. Disintegration type Additive Additive concentration (%) ^* ─── ────────────────────────── 1 (A) None 0 2 (A) CMC 103 (A) CMC 100 4 (A) Dextrin 100 5 (A) Xanthan gum 100% * Additive concentration (%):% by weight based on BC , 100% indicates that the same amount of additive as BC in the disintegrated product suspension was added.

[0074]

[Table 16] ────────────────────────────────── No. Shape of dried product Dispersibility Sedimentation (% Restoration rate of sedimentation degree (%) (Visual observation) ──────────────────────────────────1 Powder ○ 5 20 2 powder ○ 53 533 powder ○ 100 100 4 powder ○ 33775 powder ○ 92 92 ───────────────────────────── ─────

As shown in Table 16, it was found that the value of the degree of sedimentation was restored even in the dried product which was spray-dried and powdered. Furthermore, by pulverizing by spray drying, the dissolution time when redissolved in water is shorter than that of the powder of Table 13 shown in Example 12 (about 2 to 2).
10 seconds).

Example 16 A gel-form bacterial cellulose produced by stationary culture described in the comparative example of Example 1 was washed with a 0.5 N sodium hydroxide solution, and a washed and purified gel-like membrane having a thickness of about 5 mm was obtained. (Hereinafter, referred to as “gel film” or “sample A”).
This gel-like film was cut into a rhombus shape having a side of 2 mm or less using a razor (referred to as “sample B”). Further, the gel-like film was deflocculated by the method described in Example 1 to obtain a deflocculated product (referred to as “sample C”). Further, washed bacterial cellulose (“Sample D”) was obtained by the stirring culture method of Example 1.
), And further defibrated to prepare a defibrated product (referred to as "Sample E"). These samples were concentrated by centrifugation or pressing to a solids concentration of 3.1%. Next, 3.1% xanthan gum (echo gum,
A solution (produced by Dainippon Pharmaceutical Co., Ltd.) was added to the concentrated sample and kneaded with a mortar for 5 minutes to prepare a mixture. Finally, the concentration of BC and xanthan gum contained in the mixture was 1.55%. These samples were stirred using a magnetic stirrer for 3 minutes to prepare a mixed solution diluted to a BC concentration of 0.2%, and then the degree of sedimentation was evaluated. In addition, 80
After drying at 60 ° C. overnight, the re-dispersion in 60 ° C. water was measured for the degree of sedimentation, and the sedimentation degree recovery rate was calculated. In addition, dispersibility of these materials was also evaluated. Table 17 shows the results.

[0077]

[Table 17]

Compared with Samples A and B, Samples C and E which have been deflocculated have better dispersibility when water is added and redispersed after drying, and the value of the sedimentation degree restoration rate Was also found to be high. This is considered to be due to the disaggregation of BC, when adding xanthan gum, the network structure characteristic of BC was unlikely to hinder the diffusion of xanthan gum. In addition, sample D, which is a suspension in a state of being dispersed to some extent without being disaggregated due to being produced by stirring culture, was also compared with samples A and B when dried and re-dispersed by adding water. A good sedimentation restoration rate with good dispersibility was obtained. However, as compared with Sample E obtained by disintegrating Sample D, the dispersibility was slightly poor and the value of the degree of sedimentation restoration was slightly small.

Example 17 Carboxymethylcellulose manufactured by Sigma and methylcellulose manufactured by Wako Pure Chemical Industries (15 cp, 100 cp, 1500
(3 types of cp) and the disintegration product (A) of Example 1 were prepared. The BC concentration of each mixture was 0.2
% And the concentration of the additive were also 0.2%. 50 ml of each mixture was placed in a 100 ml glass beaker, and dried under normal pressure at 100 ° C. for 8 hours to prepare a dried product. In the case of carboxymethylcellulose, a sheet-like dried product having a thickness of 0.5 mm or less was formed. On the other hand, when methylcellulose was used, the mixed solution once became a gel at the stage of heating, and after drying, a porous dried product having a thickness of 1 cm or more was obtained. When water was added to these and stirred, a suspension with good dispersibility was obtained in each case.

Example 18 Xanthan gum (Echo gum, manufactured by Dainippon Pharmaceutical Co., Ltd.), galactomannan (Guapac PM-1, manufactured by Dainippon Pharmaceutical Co., Ltd.), galactomannan (Fiberlon S, manufactured by Dainippon Pharmaceutical Co., Ltd.) and the disintegrated product of Example 1 ( Three types of mixed solutions with B) were prepared. The concentration of the mixed solution is BC 1%, added water-soluble polysaccharide 0.5%
Met. These solutions are placed at 105 ° C. for 2 hours,
It was dried overnight at 0 ° C. to make it completely dry. This completely dried sample is called a sheet sample. After water was added to the sheet sample and dispersed using a mixer, dispersibility was visually observed. In addition, the degree of sedimentation restoration was also examined. As a result, in each case, the dispersion state was good, and the restoration rate of the sedimentation degree was 80% or more.

Example 19 A sheet sample dried by adding galactomannan of Example 18 was dissolved in water at 80 ° C.
The precipitate was collected by centrifugation for 20 minutes. The precipitate was re-dispersed in water at 80 ° C. and centrifuged to wash the precipitate (ie, the BC dissociated product) with water and remove galactomannan. This operation was repeated three times. The resulting precipitate was replaced with t-butanol and lyophilized,
Scanning electron microscope observation was performed (FIG. 4). As a comparative example, the disintegrated product (A) of Example 1 was freeze-dried after replacement with t-butanol, and a sheet-shaped sample obtained by drying the disintegrated product (A) at 105 ° C. for 2 hours was t-butanol. Scanning electron microscope observation was also performed on the sample obtained by the replacement. The results are shown in FIGS. As shown in the photograph of FIG. 2, the BC disintegrated product before drying had a structure in which fine fibrils of cellulose were intricately entangled in a network. On the other hand, in the BC in the form of a sheet after drying shown in FIG. 3, fine fibrils form hydrogen bonds during the drying process and are bonded to each other, and the network structure is lost. Was observed. However, when galactomannan was added, the formation of hydrogen bonds between fibrils during drying was inhibited.
It was confirmed that the network structure of fine fibrils was maintained as shown in FIG.

Example 20: Highly polymerized cellulose-producing bacteria
Stationary culture and preparation of cellulose (BC) BPR3001A was prepared from a glycerol stock in a medium 10
Inoculation was carried out at a concentration of 1% in a 750 ml volume flask equipped with 0 ml, and the cells were cultured at 28 ° C. for 3 days. After the culture, the roux flask was shaken well to remove the cells from the cellulose membrane, and 3 ml of the bacterial solution was inoculated into a Petri dish (diameter: 90 mm) containing 27 ml of CSL-Fru medium and cultured at 28 ° C for 10 days. After the cultivation, the cellulose membrane of each bacterium was washed with running water and heated in about 500 ml of water at 80 ° C. for 20 minutes. After heating, each cellulose membrane was further washed with running water, and thereafter, about 500
Lysis was achieved by heating at 80 ° C. for 20 minutes in 0.1 ml NaOH. After lysis, each cellulose membrane is
Washing was carried out by heating in 00 ml of distilled water at 80 ° C. for 20 minutes. The same washing was performed 3 to 5 times while exchanging distilled water to obtain purified BC.

Example 21: Cellulose producing bacteria of high polymerization degree
Aeration and stirring culture and preparation of cellulose (BC) BPR3001A was prepared from glycerol stock by CSL-
1% was inoculated into a 750 ml roux flask charged with 100 ml of a Fru medium, and cultured 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 added to 500 ml containing 112.5 ml of the medium.
The cells were inoculated into a ml flask and cultured at 28 ° C. and 180 rpm for 3 days. The culture was aseptically disintegrated with a blender, and 60 ml thereof was charged with 540 ml of CSL-Fru medium.
Inoculate the jar and adjust the pH to NH ₃ gas and 1N H ₂ S
While controlling the O ₄ at 4.9 to 5.1, the amount of dissolved oxygen (D
Main culture was performed while automatically controlling the number of revolutions so that O) was 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. Precipitate is also 8 times the volume of 0.1N
The cells were suspended in NaOH and heated at 80 ° C. for 20 minutes to lyse the cells. After the lysis, the precipitate was recovered by centrifugation. Thereafter, the precipitate was suspended in 8 volumes of distilled water,
The cellulose was washed by heating for 1 minute and centrifuging after heating to collect the precipitate. Purified BC was obtained by performing the same washing three times.

Incidentally, the CSL-Fru used in the above embodiment was used.
Is as shown below.

[0085]

[Table 18]

[0086]

Table 19 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

[0087]

[Table 20] Salt mixed solution ammonium iron citrate 1.5 g / l calcium chloride 1.5 g / l ammonium molybdate 0.1 g / l zinc sulfate heptahydrate 0.2 g / l manganese sulfate tetrahydrate 0.1 g / l Copper sulfate pentahydrate 2mg / l

Example 22 The purified BC obtained in Examples 20 and 21 was disintegrated in the same manner as in the case of the disintegrated product (A) described in Example 1 to obtain a disintegrated product. These are called disintegration products (E) and (F), respectively. Using the disintegrated products (E) and (F), a test similar to that described in Table 1 of Example 2 was performed. As a result, similar to the disintegrated product (A), the results shown in Table 1 were obtained. . Example 23 A sample for molecular weight analysis was prepared by drying the disintegration product (A), the disintegration product (B), the disintegration product (E) and the disintegration product (F) under reduced pressure at 80 ° C. for 12 hours. After nitration, the weight-average molecular weight was measured and the weight-average degree of polymerization was calculated according to the method already described for these samples. As a result, the weight-average degree of polymerization was 10,60 in terms of polystyrene, respectively.
0, 14,900, 22,500 and 17,400.

[0089]

The dried bacterial cellulose obtained by the drying method of the present invention is mixed with water again and reconstituted to obtain a viscosity recovery rate of about 10 to 150% and a viscosity recovery rate of about 30 to 150%.
In addition to showing the sedimentation degree restoration rate, the evaluation of the dispersion state by visual observation shows the same dispersibility as before drying, and the physical form of the bacterial cellulose fiber is not substantially impaired by the drying process of the method of the present invention. It turns out.

[Brief description of the drawings]

FIG. 1 is a graph showing a flow curve of bacterial cellulose dried and condensed by the method of the present invention.

FIG. 2 is a scanning electron micrograph of the tissue of a sample obtained by lyophilizing the disaggregated product (A) after substituting with t-butanol. The length of the white horizontal bar in the figure is 10 μm.

FIG. 3 is a scanning electron micrograph of the structure of a sample obtained by drying a disintegrated product (A) at 105 ° C. for 2 hours and substituting t-butanol for a sheet sample. The length of the white horizontal bar in the figure is 10 μm.

FIG. 4 is a scanning electron micrograph of a tissue obtained by re-dissolving a dried sample by adding galactomannan, substituting a finally obtained precipitate sample with t-butanol and freeze-drying the sample. The length of the white bar in the figure is 10 μm
It is.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasushi Morinaga 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa Prefecture Inside Biopolymer Research Co., Ltd. (72) Inventor Hiroshi Ogiya 3-chome, Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa No. 2 No. 1 Biopolymer Research Inc. (58) Field surveyed (Int. Cl. ⁶ , DB name) C08B 37/00

Claims (12)

(57) [Claims] 1. A method for drying bacterial cellulose, comprising adding a third component other than bacterial cellulose and water to an aqueous suspension containing bacterial cellulose, followed by dehydration drying. 2. The method according to claim 1, wherein the bacterial cellulose has been subjected to a defibration treatment. 3. The method according to claim 1, wherein the bacterial cellulose is bacterial cellulose obtained by stirring culture. 4. The method according to claim 2, wherein the disintegration method is a method using mechanical shearing force, ultrasonic waves, high pressure treatment, acid hydrolysis, enzymatic hydrolysis or a bleaching agent, or a combination thereof. 5. The method according to claim 1, wherein the third component is a hydrophilic liquid. 6. The method according to claim 1, wherein the third component is a hydrophilic solid. 7. The method according to claim 1, wherein the dehydration drying is spray drying, pressing, air drying, hot air drying, vacuum drying, or a combination thereof. 8. The method according to claim 1, wherein a bacterial cellulose having a weight-average degree of polymerization in terms of polystyrene of at least 1.6 × 10 ⁴ obtained by aeration and stirring culture is used. 9. The method according to claim 1, wherein a bacterial cellulose having a weight-average degree of polymerization in terms of polystyrene of 2.0 × 10 ⁴ or more obtained by stationary culture is used. 10. A dried bacterial cellulose obtained by the method according to any one of claims 1 to 9. 11. After drying bacterial cellulose by the method according to any one of claims 1 to 9,
A method for restoring a dried bacterial cellulose, which comprises adding water to form a dispersion, stirring and mixing the dispersion, and optionally performing a heat treatment before or after the stirring and mixing. 12. The water activity is 0.75 or less.
11. The dried bacterial cellulose according to item 10.