JPH09165402A - Method for drying bacterial cellulose and dried product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a dried bacterial cellulose which can show dispersibility, settleability, solution viscosity, etc., equivalent to those before being dried when it is brought again into a wet state by mixing an aqueous suspension of a bacterial cellulose with the third component except bacterial cellulose and water and dehydrating and drying the resulting mixture. SOLUTION: An aqueous suspension of a bacterial cellulose is mixed with the third component except bacterial cellulose and water, and the resulting mixture is dehydrated and dried. Examples of hydrophilic liquids used as the third component include glycerol, ethylene glycol dimethyl sulfoxide, dimethylformamide, surfactants, lactic acid, gluconic acid, delta-gluconolactone and a mixture thereof. Among them, glycerol is desirable. Examples of hydrophilic solids which can be used as the third component include water-soluble substances such as water-soluble low-molecular compounds and water-soluble polymers, water-insoluble substances and difficultly water-soluble substances.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD 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 handling such disaggregated substances of BC in a wet state, a solvent such as water, which is present in a weight several times to several hundred times the weight of the cellulose component, is used. In addition, there are various problems such as increase in storage space, increase in storage and transportation costs, and decomposition by microorganisms during storage. Therefore, if it is possible to change the disaggregated material and the like of BC from a wet state to a dry state, it is expected that the above problems 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-shaped fine fibers of bacterial cellulose are ordinary cellulose fibers, for example, much finer than plant pulp fibers, because the surface area is large, so there are many parts that contribute to hydrogen bonding,
The hydrogen bond between the fine fibers becomes 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, "condensation" means adding water to a dried product to swell it.

First, freeze-drying will be described. In freeze-drying, the sample is once frozen and then dried by sublimation of water molecules from the ice while not melting the ice. As is well known, it is necessary to take a large amount of energy when changing the phase of water into ice. At the same time, a large amount of energy is required for the phase change from ice to water vapor during sublimation. To do these things industrially on a large scale, enormous amounts of energy are required. In addition, when the freezing process is carried out for a long time during the freezing process, large ice crystals grow. When water between the fine fibers of the BC is frozen, if ice crystals larger than the voids between the fine fibers grow, association between the fine fibers of the BC occurs. Therefore, in order to prevent this phenomenon, it is necessary to perform rapid freezing. However, a large amount of energy is required for cooling for rapid freezing. Considering such points, a huge amount of energy is required to industrially perform freeze-drying. Although lyophilization is generally one of the best methods for drying various hydrous samples, such as foods, biological samples, etc., it is not widely used.
For the above reasons.

Next, problems of the solvent replacement method will be described. The voids between the BC microfibers are very small,
It is considered that a large amount of water is hydrated on the surface of the fine fibers. Therefore, in order to replace it with a solvent, a large amount of solvent and time are required. In addition, even if the solvent is replaced with a polar solvent, due to the inherent water content, the surfaces of the cellulose microfibers are firmly bound to each other by hydrogen bonds in the course of drying the solvent, and as a result, water is not formed after drying. It is difficult to return to the original BC state even after adding. Therefore, it is necessary to first replace water with a polar solvent such as alcohol, and then through acetone or the like, and finally with a nonpolar solvent such as hexane, and then perform drying. To carry out these processes industrially,
It requires large amounts of solvent, a lot of time, and dangerous and complicated processes. For the reasons described above, neither freeze-drying nor solvent replacement is a satisfactory method for drying BC. The present inventors have found that the conventional problems can be solved by adding BC and a third component other than water to an aqueous suspension of BC, and then drying, and completed the present invention. It was

[0007]

That is, the present invention is characterized by adding bacterial cellulose and a third component other than water to an aqueous suspension containing bacterial cellulose, and then dehydrating and drying the bacterial cellulose. It is related to the drying method. The present invention also relates to a dried bacterial cellulose product 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,
Mention may be made of glycerin, ethylene glycol, dimethylsulfoxide, dimethylformamide, surfactants, lactic acid, gluconic acid and deltagluconolactone and mixtures of one or more thereof. Among these, glycerin is preferable. Further, the hydrophilic solid that can be used as the third component includes a water-soluble substance such as a water-soluble low molecule and a water-soluble polymer, and a water-insoluble substance and a poorly water-soluble substance.

Among these, water-soluble low-molecular weight compounds include, for example, sugars (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.

The water-soluble polymer is, for example, a cellulose derivative (carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, ethylcellulose), xanthan gum, xyloglucan, dextrin, dextran, carrageenan, locust bean gum, alginic acid, alginate, pullulan, Starch, potato starch, kudzu flour, 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 poorly water-soluble substance means, for example, rice flour, wheat flour, barley flour, rye flour, soybean flour, adzuki 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, micro hollow particles, cellulose particles, lauroyl lysine and diatomaceous earth, and a mixture of one or more thereof.

The third component described above is selected by a person skilled in the art depending on the purpose of 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 making an inorganic powder sheet in the field of papermaking, the binding characteristics of BC and the inorganic powder, and the function of the inorganic powder (for example, magnetic powder) can be efficiently achieved in the prepared inorganic powder sheet. In order to achieve good expression, the dried material of the present invention as a raw material contains BC disaggregated material, magnetic inorganic powder, acrylamide (coagulant), cationized starch (paste), for example, 100: 15: 1: 3. What is mixed and dried at a ratio of about may be used. As another example, when used as a thickener in the food field, xyloglucan, salt, sucrose, etc. are used, 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 compounded feed for cultured fish as the third component, a dried bacterial cellulose of the present invention useful as a moist pellet feed for cultured fish containing bacterial cellulose as a binder, or as dog food or cat food. Can be obtained. Those skilled in the art can appropriately select the addition amount of these third components depending on the type of substance and the like, and are usually 2 to 1,000% by weight based on the weight of BC. Furthermore, as an example of the bacterial cellulose aqueous suspension containing the third component, the culture solution of the cellulose-producing bacterium itself or the one containing the third component may be used. In particular, as described above, when the dried bacterial cellulose of the present invention is used as various feeds, the bacterial cells themselves are also contained in the obtained product, which enhances the nutritional value of the feed. 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 device specifically used in the method of the present invention are as follows. That is, a continuous tunnel dryer, a band dryer, a vertical dryer,
Vertical turbo dryer, multi-stage disc dryer, aeration dryer, rotary dryer, air stream dryer, spray dryer, cylinder dryer, drum dryer, screw conveyor dryer, rotary dryer with heating tube, vibration transportation Drying device, batch-type box drying device, aeration drying device, vacuum box drying device,
And a drying device such as a stirring drying device can be used alone or in combination of two or more. Examples of the method for supplying thermal energy to the material to be dried in drying include direct heating, radiant heating, and indirect heating. Among them, infrared heating, microwave heating, etc. are particularly preferable from the viewpoint of energy efficiency.

By using the apparatus as described above, BC can be dried so that it can be restored to the original wet state. In the present specification, the “dry” state does not mean an absolutely dry state in which there is no water contained in the dried product. That is, it is about 25% or less of 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 polar group such as a hydroxyl group in the molecule and thus have an action of adsorbing water,
In the case of low molecular weight, it may have a function of retaining water in the form of crystal water, so even if a dried product that seems to be dried is obtained by performing drying with the method and apparatus described above. 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 at a level at which microorganisms cannot grow. A water activity value of 0.9 or less, preferably 0.75 or less is required.

In the method of the present invention, the cellulosic material is preferably one that has been subjected to disaggregation 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 disaggregation treatment can be carried out by acid hydrolysis, enzymatic hydrolysis 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. The actual application of these mechanical external forces to bacterial cellulose can be achieved by using, for example, a mixer, a polytron, an ultrasonic oscillator or the like.

In the disaggregation treatment by the mixer, the mechanical external force mainly consists of the impact force caused by the collision of the stirring blade and the bacterial cellulose and the shear force generated by the displacement phenomenon due to the speed difference 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.

The disaggregation treatment has been described above. The disaggregation treatment according to the present invention is performed after stirring culture of the cellulose-producing bacterium.
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 a function of disaggregating the bacterial cellulose, and in the stirring culture, the dissociation treatment of the bacterial cellulose can be sufficiently performed even by the stirring function for the purpose of culturing. Furthermore, the same can be said for the operations of separating, washing, purifying and transporting the 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.

The stirring culture as referred to in the present invention is a culturing method which is carried out while stirring a culture solution, and the structure of bacterial cellulose, for example, decreases in crystallization index due to the stirring action received during the stirring culture. The crystal parts change so as 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. The culture operation method includes 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 carrying out the stirring culture,
For example, stirring tanks such as jar fermenters and tanks,
In addition, baffled flasks, Sakaguchi flasks, and air-lift type stirring tanks can be used, but are not limited thereto. In the stirring culture according to the present invention, at the same time as 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 cellulosic bacteria which produce BC used in the present invention are, for example, 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).

Examples of the chemical mutation treatment method using a mutagen such as NTG include, 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 cells producing a high degree of polymerization that can be used in the present invention, BPR
3001A was deposited on June 12, 1995, with the Patented Microorganisms Depositary Center, Biotechnology and Industrial Technology Research Institute, Ministry of International Trade and Industry, under the 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 types of cellulose such as BC in the present invention is determined by GPC having RI as a detector.
It measures 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. The standard polystyrene (Tosoh) is used to calculate the molecular weight, and the relative molecular weight in terms of polystyrene is calculated. 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) is approximated to create 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 for stirring culture of the present invention, carbon sources include sucrose, glucose, fructose, mannitol, sorbitol, galactose,
Maltose, erythritol, 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,
It is also possible to use sugar cane juice, fruit juice such as citrus fruits, etc. in addition to sucrose. As the nitrogen source, ammonium salts such as ammonium sulfate, ammonium chloride and ammonium phosphate, nitrates, organic or inorganic nitrogen sources such as urea can be used, or Bacto
-Natural nitrogen-containing nutrient sources such as Peptone, Bacto-Soytone, Yeast-Extract, and soybean concentrate 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, sulfite waste liquor, ligninsulfonic acid, etc. may be added.

When using an auxotrophic mutant that requires amino acids and the like for growth, 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, pyrroloquinoline quinone (PQQ) (Japanese Patent Publication No. 5-1718; Mitsuo Takai, Paper and Paper Cooperative Journal, 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
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 agitation 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 the bacterial cells as they are, and may be further treated to remove impurities other than the cellulosic material including 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 redispersed in water and then mixed with stirring to restore the original wet state of the disaggregated product or the like. It is also possible to perform an appropriate heat treatment before or after the stirring and mixing operation, and the heat treatment may promote the restoration. Further, it is possible to perform more preferable restoration by performing the above-mentioned disaggregation treatment during the stirring and mixing. When the dried material of bacterial cellulose obtained by the method of the present invention is reconstituted to restore the original disaggregated state, the cellulose fine fibers constituting BC 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 disaggregated state, a large amount (cellulosic fine fibers) is present on the surface of such fine fibers or in the voids of the network structure composed of fine fibers. (A few times to several hundred times the weight of the liquid component). As described above, since a large amount of liquid component is contained, good dispersibility, sedimentation property, and liquid viscosity can be obtained. On the other hand, regardless of the method of the present invention, as is conventionally known, even if water is simply added to the dried product obtained by simply drying the disaggregated product of BC, the state is restored to such a state. 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 disaggregated material before drying. Sedimentation degree of suspension Sedimentation degree is measured by adding 10 ml of 0.2% bacterial cellulose (BC) suspension to a 15 ml tube made of Falcon, centrifuging at 3000 rpm for 15 minutes, and then sedimenting. It was expressed as a ratio of the volume of a part to the whole. 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 a dynamic viscosity at an angular velocity of 10 rad / sec at 30 ° C. when an aqueous suspension having a BC content of 0.1% is measured by a dynamic liquid viscoelasticity measuring method (hereinafter, Simply called viscosity). More specifically, a dynamic liquid viscometer (“FLUIDS SPECTROMETER RF” manufactured by Rheometrics) is used.
S II "was used to measure 2 ml of an aqueous suspension of BC disaggregate having a concentration of 0.1% between parallel rotating disks having a diameter of 5 cm, and the temperature was 30 ° C and the angular velocity was 10 rad / sec and the strain was 10%. It has a high viscosity.

[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 Cultivation Aseptically inoculating 60 ml of the above seed bacterial solution into a small jar fermenter (total volume 1000 ml) in which 540 ml of sterilized medium for stirring culture described later is put 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) Stirring culture in which carboxymethyl cellulose is added In the stirring culture described in (2), as the medium component,
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) Disaggregation treatment of bacterial cellulose Water was added to the washed bacterial cellulose obtained by the stirring culture method of (2), and suspended at a disaggregation concentration (dry weight of bacterial cellulose / volume) of about 0.2% by weight. 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
Disaggregated for a minute. 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 prepared by adding sedimentable light calcium carbonate to the disaggregated product (A) prepared in Example 1 was mixed for 15 minutes using a pulp disintegrator (manufactured by Kumagai Riki Kogyo Co., Ltd.). The amount of calcium carbonate added is 0.1 with respect to the amount of BC contained in the disaggregated material.
Double, 5-fold, 50-fold, and 500-fold. Put a part of the mixed solution in a 100 cm ² container so that the depth is 2 cm.
It was dried at 0 ° C. under normal pressure. It took 48 hours to dry. The dried product obtained after drying was plate-shaped. After adding 200 ml of water to the plate-like dried product and allowing it to stand for 3 minutes, the mixture was stirred with a spoon for 2 minutes and 30 seconds. The dispersed state as the disaggregated product characteristics of the mixed solution obtained after stirring was observed. Table 1 shows the results.

[0032]

[Table 1] X: The dispersed state of BC is not observed. Δ: Aggregation and adhesion of BC are partially observed. ◯: A dispersed state similar to the dispersed state of the disaggregated product before drying.

It was found that when calcium carbonate was added in an amount of 5 times or more of BC in the disaggregated material, the dispersed state of the disaggregated material was restored to the state before drying when the water was reconstituted after drying. When it was added 50 times or more, good recovery of the dispersed state was observed when it was added. Using the disaggregated materials (C) and (D) prepared in Example 1 instead of the disaggregated material (A), the same test was conducted. As a result, the same effect as that of the disaggregated product (A) was obtained. Further, the mixed solution was heat-treated. The heat treatment conditions were 120 ° C. and 20 minutes using a pressure steam sterilizer. After the heat treatment, the mixed liquid was cooled to room temperature, and then the dispersed state of the mixed liquid was observed.
Table 2 shows the results.

[0034]

[Table 2] X: The dispersed state of BC is not observed. Δ: Aggregation and adhesion of BC are partially observed. ◯: A dispersed state similar to the dispersed state of the disaggregated product before drying.

It was found that the dispersion state was improved in the system containing 5 times the amount of calcium carbonate by performing the heat treatment, as compared with the case where the heat treatment was not performed (Table 1). The same experiment (condensation after drying and heat treatment after condensate) was also performed on the disaggregated product (B), and as a result, in a system in which calcium carbonate was added in an amount 5 times or more that of BC,
Recovery of the dispersed state was confirmed by condensing water after drying.

Example 3 2 L of a liquid prepared by adding settling light calcium carbonate to the disaggregated product (B) prepared in Example 1 was mixed for 15 minutes using a pulp disintegrator (manufactured by Kumagai Riki Kogyo Co., Ltd.). The amount of calcium carbonate added is 0.1 with respect to the amount of BC contained in the disaggregated material.
Double, 5-fold, 50-fold, and 500-fold. A part of the mixed solution was filtered through a 200-mesh polyethylene terephthalate plain-woven mesh. The filtration area was about 150 cm ² . After a few tens of minutes have passed, when almost no liquid has come out of the lower surface of the filter mesh, the plain weave mesh made of polyethylene terephthalate of 200 mesh of the previous period is laid on the wet mat formed on the upper surface of the filter mesh, and then thick The filter paper (Whatman 3MM) of 1 was further stacked, and a pressure of about 20 g per 1 cm ² was applied for 15 minutes to squeeze the water content of the wet mat. After squeezing and dehydration, the wet mat was taken out, sandwiched between 100 mesh nets made of stainless steel from above and below, further sandwiched by a stainless steel plate having a thickness of 3 mm, and squeezed and dried at 150 ° C. for 7 minutes. The pressing pressure was 400 g / cm ² . The dried product obtained by the press-drying was in the form of a thin film or cracked flakes. 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 with a spoon for 300 seconds. The dispersed state as the disaggregated product characteristics of the mixed solution obtained after stirring was observed. Table 3 shows the results.

[0037]

[Table 3] X: The dispersed state of BC is not observed. Δ: Aggregation and adhesion of BC are partially observed. ◯: A dispersed state similar to the dispersed state of the disaggregated product before drying.

The non-added product or the dried product obtained by squeezing and drying after adding 0.1 times the amount of calcium carbonate had the same shape after the condensate, while the calcium carbonate was in the disaggregated product. It was found that the dispersed state of the disaggregated product is restored to the state before drying when the water is reconstituted after drying when BC is added 5 times or more to BC. When it was further added 50 times or more, good recovery of the dispersed state was observed. Further, the mixed solution was heat-treated. The heat treatment conditions were 120 ° C. and 20 minutes using a pressure steam sterilizer. After the heat treatment, the mixed liquid was cooled to room temperature, and then the dispersed state of the mixed liquid was observed. Table 4 shows the results.

[0039]

[Table 4] X: The dispersed state of BC is not observed. Δ: Aggregation and adhesion of BC are partially observed. ◯: A dispersed state similar to the dispersed state of the disaggregated product before drying.

Comparing with those not subjected to the heat treatment (Table 3), it was found that the heat treatment improved the dispersion state in the system in which the amount of calcium carbonate was increased by 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 added is 0 with respect to the weight of BC contained in the disaggregated material,
It was set to 2, 10, 50, 100, 150, 200%. 100 ml of each mixed solution was dried at 100 ° C. to a constant weight. After drying, the mixture was cooled to 4 ° C., 100 ml of distilled water was added, and the mixture was left standing for 15 minutes. After standing, these liquids were stirred and mixed for 20 seconds using a pencil mixer. The dispersed state of the disaggregated material after stirring and mixing was visually observed. The heat treatment was carried out at 100 ° C. for 1 hour before stirring and mixing, and the dispersed state of the disaggregated material was also visually observed in the same manner as for stirring and mixing. The results are shown in Table 5.

[0042]

[Table 5] Addition amount of glycerin during drying and dispersal state of disaggregated material after condensing after drying (visual observation) ──────────────────────── ──────────── Glycerin addition amount After drying, adding water and drying, and then adding water, then heat (%, relative to BC weight) Stirred mixed disaggregated material Treated and stirred mixed Disaggregated material (A) (B) (A) (B) ──────────────────────────────────── 0 (no addition) × × × × 2 △ △ ○ ○ 10 △ △ ○ ○ 50 ○ ○ ○ ○ 100 ○ ○ ○ ○ 150 ○ ○ ○ ○ 200 ○ ○ ○ ○ ──────────── ──────────────────────── ×: The dispersed state of BC is not observed. Δ: Aggregation and adhesion of BC are partially observed. ◯: A dispersed state similar to the dispersed state of the disaggregated product before drying.

Incidentally, (A) and (B) in the table correspond to the disaggregated products (A) and (B) prepared in Example 1, respectively. It was found that in a system in which glycerin was added in an amount of 2% or more of BC, the dispersed state of BC was recovered by adding water after drying.

Example 5 The viscosities of disaggregates containing various concentrations of glycerin prepared in Example 4 were compared before drying and after dry condensate heat treatment. However, the sample used in the experiment was only the disaggregated product (A). Rheometrics, a dynamic liquid viscoelasticity measuring device, is used to measure viscosity.
Sample 2 between parallel rotating disks with a diameter of 5 cm
The dynamic viscosity was measured at a temperature of 30 ° C. when the disc was vibrated with an angular velocity of 10 rad / sec and a strain of 10%. The concentration of BC contained in the sample was adjusted to 0.1% by adding distilled water. The measurement results are shown in Table 6 below.

[0045]

[Table 6] ──────────────────────────────────── Glycerin addition amount Disaggregation product viscosity (P) Viscosity restoration Rate (%, relative to BC weight) Before drying After drying, condensate, heat treatment (%) ─────────────────────────────── ───── 0 (no additive) 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 5.5 79.9 ──────────── ────────────────────────

The viscosity recovery rate in Table 6 is a value obtained by dividing the viscosity of the disaggregated product after the dry condensing heat treatment by the viscosity of the disaggregated product before drying in percentage. It was found that in the absence of additives, the viscosity of the disaggregated product after condensing was about 6% or less before drying, and the original properties of the disaggregated product were lost by drying. However, it was found that the characteristics of the disaggregated product were retained to some extent after the condensate by adding glycerin and drying.

Example 6 The sedimentation degree of the sample of Example 5 was measured. The sedimentation degree was measured by adding 10 ml of the disaggregated material to a 15 ml tube made of Falcon, centrifuging the mixture at 3000 rpm for 15 minutes, and then describing the ratio of the volume of the sedimented portion to the total volume. Table 7 shows the results.

[0048]

[Table 7] ─────────────────────────────────── Amount of glycerin Disaggregate Sedimentation degree (%) Sedimentation Degree of recovery (%, relative to BC weight) Before drying After drying, condensate, heat treatment (%) ───────────────────────────── ──────── 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 recovery rate of sedimentation degree in Table 7 is expressed by a value obtained by dividing the sedimentation degree of the disaggregated material after the dry condensing heat treatment by the sedimentation degree of the disaggregated material before drying.

Example 7 To 50 ml of the disaggregated product (A) having a BC content of 0.2% prepared in Example 1, carboxymethyl cellulose (Sigma: Medium viscosity) was adjusted to 0.1, 1, 10,
50 and 250 mg were melted. Dispersibility, sedimentation degree, and viscosity were measured as disaggregation properties of these mixed liquids. The drying conditions were 50 ° C. for 5 hours and 80 ° C. for 2 hours, which was a total of 7 hours, and then at 105 ° C., the sample had a sheet-like appearance and was dried to a substantially constant weight. Table 8 shows the results.

[0051]

[Table 8] X: The dispersed state of BC is not observed. Δ: Aggregation and adhesion of BC are partially observed. ◯: A dispersed state similar to the dispersed state of the disaggregated product before drying.

In the case of no addition, the characteristics of the disaggregated material were lost by the drying step. However, when 10 mg or more of carboxymethyl cellulose was added, the disintegrated material such as dispersibility and viscosity was passed through the drying step. It has been found that the characteristics of the will be considerably retained.

Example 8 The disaggregated product (A) prepared in Example 1 was concentrated using a centrifuge and distilled water was added to obtain a disaggregated product having a concentration of 1%.
20 parts of this disaggregated material and 80 parts of various solutions shown in Table 7 were mixed and then dried. After drying, 100 parts of 80 ° C. water was added, and the mixture was allowed to stand at 80 ° C. for 30 minutes and then stirred using a pencil mixer. The dispersibility and sedimentation degree of the obtained mixed liquid were evaluated at room temperature. As a comparison target, only the disaggregated product (A) was used. In addition, after drying for 50 minutes using a far-infrared dryer, the drying condition is 80 ° C. for 3 minutes.
It dried under reduced pressure for hours.

[0054]

[Table 9] Types and concentrations of various solutions mixed with disaggregated substances (unit: w / v%) ──────────────────────────── ────── Additive Concentration (%) ───────────────────────────────── 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 characteristics of the disaggregated product were lost in the drying process. However, in all cases where the substances in Table 9 above were added, an improvement in the properties of the disaggregated product was observed after the condensate. That is, as a result of visual observation, a good dispersion state was obtained, and all of the above-mentioned sedimentation degree restoration rates were 25.
% Or more.

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

[0057]

[Table 10]

80 ml of a sample of the mixture having the composition shown in Table 10 was used.
After drying overnight at ℃, it was further dried at 105 ℃ for 30 minutes using infrared rays. 100 ml of tap water is added to the dried product.
After the addition, the mixture was stirred with a magnetic stirrer for 1 hour. Then, autoclave sterilization was performed at 120 ° C. for 20 minutes. After being taken out from the autoclave and cooled at room temperature, the properties of the disaggregated product were evaluated. The results are shown in Table 11.

[0059]

[Table 11]

It was found that, when the additives were added and dried, the characteristics of the disaggregated product were not lost in terms of dispersibility, sedimentation degree, viscosity and the like even after the drying step.

Example 10 1 L of the disaggregated material (A) prepared in Example 1 was mixed with rice flour (fraction obtained by dry-milling rice and then passing through a 200-mesh sieve),
Wheat flour, soybean flour, buckwheat flour, crushed wheat bran powder (fraction that passed through a 80-mesh sieve after dry crushing), corn flour, activated carbon, talc, kaolin, calcined kaolin,
Titanium dioxide, aluminum hydroxide, celite, bentonite, silica, colloidal chitin freeze-dried powder (colloidal chitin was freeze-dried, wet-milled in ethyl ether and then dried), polystyrene latex (average particle size 10 μm), diatomaceous earth, Avicel One of which is 98g
Add and mix well. Each mixed solution was dried at 80 ° C. under normal pressure for 48 hours and under reduced pressure for 48 hours. 1L after drying
Add water and keep the temperature at 50 ° C with a stirrer.
The mixture was stirred at 00 to 400 rpm for 3 hours. After stirring, the dispersibility of BC in the mixed solution was evaluated with the naked eye and a polarizing optical microscope. In addition, the sedimentation degree was measured using a part of each mixed solution. When the disaggregated product (A) was dried without adding anything, the dispersibility became poor even if hot water was added and stirred, and the properties of the disaggregated product were lost by drying. When it was dried by drying, the dispersibility after condensate was good, and the settling degree restoration rate was 33% or more in all cases.

Example 11 To 50 ml of the disaggregated material (A) prepared in Example 1, 0.2 g of sodium sulfate, 0.5 g of sodium chloride or 0.2 g of sodium bicarbonate was mixed using a magnetic stirrer. These mixed liquids were dried using a far-infrared dryer until the weight of each became 1 g or less, and a semi-dried product was obtained. These semi-dried products were placed in a batch type microwave heating device and dried while aeration was performed to obtain a dried product having a water content of 1% or less. After pulverizing each dried product 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 these dispersibility and sedimentation rate restoration rate were evaluated,
Compared to the case of no addition, the dispersibility was good in all cases, and the sedimentation degree recovery rate was a good value of 25 to 50%. Table 12 shows the results.

[0063]

[Table 12] ──────────────────────────── Additive Dispersibility ^{* 1} Sedimentation recovery rate (%) ───── ─────────────────────── Sodium sulfate ○ 43.4 Salt ○ 29.1 Sodium bicarbonate ○ 30.0 No additives × 13.6 ─── ───────────────────────── * 1 Dispersibility when compared to the dispersibility before drying (○: The same dispersibility as before drying, X: Dispersibility before drying is not restored)

Example 12 1 L of the disaggregated product (A) prepared in Example 1 was concentrated using a centrifuge to obtain a cake of the dissociated product having a wet weight of 35 g. This cake was added to 100 ml of 2% dextrin, thoroughly stirred and mixed by suspension. This solution was put into a polypropylene container to a depth of about 1 cm and then dried at 105 ° C. A sheet-like material was obtained after drying. 2 g of this sheet-like substance is taken and the particle size is 4
It was pulverized until it became less than 00 μm. The properties of the above-mentioned sheet material and this powder were compared. First, the bulk density was measured. The bulk density of each was calculated according to the following formula. Bulk density of sheet material = weight of sheet material / (area of sheet material × thickness of sheet material) A caliper was used to measure the thickness. Bulk density of powder = weight of powder / volume of powder The volume of the powder was measured by putting the prepared powder in a beaker.

After evaluating the bulk density, finally, water was added to the sheet-like substance and powder having a BC concentration of 0.2%. These mixed liquids were stirred for 10 minutes with a magnetic stirrer to prepare a disaggregated product solution. The time required for dissolution when preparing the solutions and the solubility, dispersibility, sedimentation degree recovery rate, and viscosity recovery 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] Properties of sheet material and powder ────────────────────────── Shape before condensate Sheet material powder ──── ────────────────────── Bulk density (g / cm ³ ) 1.0 0.59 Dissolution time ^{* 1} (sec) 240 30 Dispersibility ○ ○ Sedimentation Degree of recovery (%) 99 107 Viscosity recovery (%) 102 100 ────────────────────────── * 1 Dissolution time The time was set until no large lumps were observed with the naked eye.

By powdering the dried product, the time required for condensing water can be shortened. Further, it was found that the sheet-like material has a large bulk density and is advantageous in storage.

Example 13 1 L of the disaggregated product (A) prepared in Example 1 was concentrated using a centrifuge to obtain a cake of the dissociated product having a wet weight of 35 g. This cake was added to 100 ml of a 2% dextrin solution or 100 ml of a 1% carboxymethylcellulose solution, thoroughly stirred and mixed by suspension. After putting this solution in a polypropylene container to a depth of about 1 cm, 10
Dried at 5 ° C. A sheet-like material was obtained after drying.
Water was added to this sheet-like substance so that the BC concentration was 0.1%, and the mixture was thoroughly stirred and mixed, 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 (Rheometrics). In addition, these results were compared with the liquid obtained by diluting the disaggregated product (A) before drying with double the distilled water. The results are shown together in FIG. The dried product with the addition of dextrin showed a flow curve similar to that of the disaggregated product before drying. In other words, it was a value with a yield value. On the contrary,
It was confirmed that when carboxymethyl cellulose was added, the yield value became almost zero, and the apparent viscosity was significantly reduced compared with the disaggregated product before drying.

Example 14 The disaggregated product (A) prepared in Example 1 was filtered and concentrated using three meshes of 400-mesh polyethylene terephthalate stacked. Water was removed from this concentrate by using a shake-off centrifuge to obtain a cake having a solid content of 6.1%. For 10 parts of this cake, dextrin 5
Parts, xanthan gum 2 parts, and sucrose 1 part were added and mixed well. Next, this mixture was sandwiched between two stainless plates and pressed to a thickness of about 1-2 mm. The temperature during pressing was 75 ° C. Place the resulting plate-shaped cake on a 10-mesh stainless mesh,
And 105 ° C. for 2 hours under atmospheric pressure.
The plate-like dried product obtained after drying was crushed into about 3 mm square with scissors, and water was added so that the BC concentration became 0.2%, and the mixture was stirred at 30 ° C. for 50 minutes. Stirring is 40
With a stirring speed of 0 rpm, a 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 solid particles were not observed by visual observation was obtained. The dispersibility of this suspension (a) and the recovery rate of sedimentation degree were measured. Next, the suspension (a) was disaggregated using a blender. The disaggregation conditions are 18000 rpm using the bladed one.
It was carried out for 3 minutes at 25 ° C. to obtain a disaggregated product suspension (referred to as suspension (b)). The dispersion state of this suspension (b) and the recovery rate of sedimentation degree were measured. The dispersibility and the sedimentation rate recovery rate were measured after deaeration under vacuum to sufficiently remove the bubbles in the suspension. The results are shown in Table 14.

[0070]

[Table 14] Characteristics of suspensions (a) and (b) ────────────────────────── Suspension (a) Suspension Liquid (b) ────────────────────────── Dispersibility ○ ○ Sedimentation recovery rate (%) 80 100 ──────── ────────────────────

It was found that the disintegration after condensing water promotes the restoration of the characteristics after drying.

Example 15 A mixed solution was prepared by mixing the disaggregated product (A) prepared in Example 1 with the additives shown in Table 15. The concentration of each disaggregated substance contained in this mixed solution was 0.2% by weight. After this, spray drying was performed.
SPRAY DRYER DL41 manufactured by Yamato Kagaku Co., Ltd. is used as a spray dryer, and the conditions are 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 to 70 / min.
It was set at 0 liters. The shape of the obtained dried product was observed. In addition, water was added to this powder so that the BC concentration was 0.2%, and then the solution was prepared by stirring for 10 minutes using a magnetic stirrer. The dispersibility, sedimentation degree, and sedimentation degree restoration rate of these solutions were evaluated. Table 16 shows the results.

[0073]

[Table 15] ───────────────────────────── No. Disaggregate type Additives Additive concentration (%) ^* ─── ────────────────────────── 1 (A) None 0 2 (A) CMC 10 3 (A) CMC 100 4 (A) Dextrin 100 5 (A) Xanthan gum 100 ───────────────────────────── * Additive concentration (%):% by weight based on BC , 100% means that the same amount of additive as BC in the disaggregated product suspension was added.

[0074]

[Table 16] ────────────────────────────────── No. Shape of dried product Dispersibility Sedimentation degree (% ) Sedimentation restoration rate (%) (visual observation) ─────────────────────────────────── 1 powder ○ 5 20 2 powder ○ 53 53 3 powder ○ 100 100 4 powder ○ 33 77 5 powder ○ 92 92 92 ────────────────────────────── ─────

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

Example 16 Gel-like bacterial cellulose produced by static culture described in the comparative example of Example 1 was washed with 0.5N sodium hydroxide solution to give a washed and purified gel-like membrane having a thickness of about 5 mm. Was obtained (hereinafter referred to as "gelled film" or "sample A").
This gel-like film was cut with a razor into dices having a side of 2 mm or less (referred to as "Sample B"). Further, the gel film was disaggregated by the method described in Example 1 to obtain a disaggregated product (referred to as "Sample C"). Furthermore, washed bacterial cellulose (“Sample D”) was prepared by the stirring culture method of Example 1.
Was obtained), and this was disintegrated to prepare a disaggregated 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 (manufactured by Dainippon Pharmaceutical Co., Ltd.) (however, a suspension was prepared because it was not completely dissolved) was added to the concentrated sample and kneaded for 5 minutes in a mortar to prepare a mixture. The concentration of BC and xanthan gum finally contained in the mixture was 1.55%. These samples were stirred for 3 minutes using a magnetic stirrer 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 being dried at 60 ° C. overnight, the re-dispersed product in water at 60 ° C. was measured for sedimentation degree, and the sedimentation degree restoration rate was calculated. In addition, dispersibility of these materials was also evaluated. Table 17 shows the results.

[0077]

[Table 17]

Compared with Sample A and Sample B, the disaggregated Sample C and Sample E have good dispersibility when water is added and redispersed after drying, and the value of the sedimentation rate recovery rate is It turned out to be expensive. It is considered that this is because by disaggregating BC, the network structure characteristic of BC was difficult to hinder the diffusion of xanthan gum when xanthan gum was added. Sample D, which is a suspension that has been dispersed to some extent without being disaggregated because it was produced by agitation culture, is also compared to Samples A and B when it is redispersed by adding water after drying. The dispersibility was good and a high sedimentation rate recovery rate was obtained. However, when compared with the sample E obtained by disaggregating the sample D, the dispersibility was slightly poor and the value of the degree of sedimentation restoration was also small.

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

Example 18 Xanthan gum (Echo gum, manufactured by Dainippon Pharmaceutical), galactomannan (Guapack PM-1, manufactured by Dainippon Pharmaceutical), galactomannan (Fibrelon S, manufactured by Dainippon Pharmaceutical) and the disaggregated 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. Add these solutions at 105 ° C for 2 hours, then 8
It was dried at 0 ° C for a whole day and night to be completely dried. This absolutely dried product is called a sheet sample. Water was added to this sheet sample and dispersed using a mixer, and then the dispersibility was visually observed. Also, the sedimentation rate recovery rate was investigated. As a result, in all cases, the dispersed state was good, and the recovery rate of the sedimentation degree was 80% or more.

Example 19 The sheet-shaped sample obtained by adding the galactomannan of Example 18 and drying was dissolved in water at 80 ° C., and then rotated 3500 times.
The precipitate was collected by centrifugation for 20 minutes. The precipitated portion was redispersed again in water at 80 ° C. and centrifuged to wash the precipitated portion (that is, BC disaggregated product) with water and remove galactomannan. This operation was repeated three times. The finally obtained precipitate was replaced with t-butanol and freeze-dried.
Scanning electron microscope observation was performed (FIG. 4). In addition, as a comparative example, the disaggregated product (A) of Example 1 was lyophilized after substitution with t-butanol, and a sheet-like sample obtained by drying the disaggregated product (A) at 105 ° C. for 2 hours was used as t-butanol. Scanning electron microscope observation was also performed on the sample obtained by substituting. The results are shown in FIGS. As shown in the photograph of FIG. 2, the disaggregated product of BC before drying had a structure in which fine cellulose fibrils were intricately entangled in a mesh. On the other hand, in the sheet-like BC after drying shown in FIG. 3, fine fibrils form hydrogen bonds during the drying process and are bound to each other, and the network structure is lost. Was observed. However, the addition of galactomannan hinders the formation of hydrogen bonds between fibrils during drying, so that when galactomannan is suspended in water,
It was confirmed that the fine fibril network structure was maintained as shown in FIG.

Example 20 Cellulose-producing bacteria with high degree of polymerization
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 Production of High Polymerization Cellulose Producing Bacteria
Aeration and stirring culture and preparation of cellulose (BC) BPR3001A was prepared from glycerol stock by CSL-
1% of the cells were inoculated into a 750 ml roux flask charged with 100 ml of Fru medium and statically 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 disaggregated with a blender, 60 ml of which 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 rotation speed so that (O) was 3.0% or more. After the completion, the obtained culture solution was diluted about 5 times with acetate buffer and then centrifuged to collect the 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 is also 8 times the amount of 0.1N
Lysis was carried out by suspending in NaOH and heating at 80 ° C. for 20 minutes, and then the precipitate was recovered by centrifugation after lysis. 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 examples.
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 mixture liquid 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 2 mg / l

Example 22 The purified BC obtained in Examples 20 and 21 was disintegrated in the same manner as in the disaggregated product (A) described in Example 1 to obtain a disaggregated product. These are called disintegration products (E) and (F), respectively. Using these disaggregated products (E) and (F), the same test as described in Table 1 of Example 2 was carried out, and as a result, the same results as shown in Table 1 were obtained as with the disaggregated product (A). . Example 23 The disaggregated product (A), the disaggregated product (B), the disaggregated product (E) and the disaggregated product (F) were dried under reduced pressure at 80 ° C. for 12 hours to prepare a sample for molecular weight analysis. 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]

[Effect] The bacterial cellulose dried product obtained by the drying method of the present invention is mixed with water again and recondensed to obtain a viscosity recovery rate of about 10 to 150% and about 30 to 150%.
In addition to showing the settling degree restoration rate, the dispersibility is the same as that before drying in the evaluation of the dispersed state by visual observation, and the physical form of the bacterial cellulose fiber is not substantially impaired by the drying process of the method of the present invention. I knew that.

[Brief description of the drawings]

FIG. 1 is a graph showing a flow curve of bacterial cellulose that has been recondensed after being dried 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 it 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 substituting a sheet-like sample obtained by drying the disaggregated product (A) at 105 ° C. for 2 hours with t-butanol. 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 redissolving a dried sample by adding galactomannan, substituting the finally obtained precipitated sample with t-butanol, and lyophilizing it. The white horizontal bar in the figure has a length of 10 μm.
It is.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 28, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction contents]

[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 disaggregated material before drying. Sedimentation degree of suspension The method of measuring the sedimentation degree was as follows: 10 ml of a suspension containing 0.2% of bacterial cellulose (BC) was used for 15 m of Falcon.
After being centrifuged at 3000 rpm for 15 minutes, the volume of the sedimented portion was expressed as a ratio to the whole 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 an angular velocity of 10 rad / sec at 30 ° C. when an aqueous suspension having a BC content of 0.1% is measured by a dynamic liquid viscoelasticity measuring method.
A value (hereinafter, simply referred to as "viscosity"). More specifically, dynamic liquid viscoelasticity measuring apparatus (Rheometrics
"FLUIDS SPECTROMETER R"
FS II "is used, 2 ml of an aqueous suspension of 0.1% concentration of BC disaggregate is sandwiched between parallel rotating disks having a diameter of 5 cm, and the angular velocity is 1 to 100 rad / sec at a temperature of 30 ° C.
Angular velocity when changing to 10 rad / sec strain 1
Viscosity measured at 0%.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction contents]

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 added is 0 with respect to the weight of BC contained in the disaggregated material,
It was set to 2, 10, 50, 100, 150, 200%.
100 ml of each mixed solution was dried at 100 ° C. to a constant weight. After drying, cool to 4 ℃ and add distilled water to 100
After adding ml, the mixture was allowed to stand for 15 minutes. After standing still, these liquids were stirred and mixed for 20 seconds using a pencil mixer (manufactured by Iuchi Seieidou) . The dispersed state of the disaggregated material after stirring and mixing was visually observed. In the same manner, the dispersed state of the disaggregated substances was also visually observed with respect to the one that was heat-treated at 100 ° C. for 1 hour before stirring and mixing and then stirred and mixed. Table 5 together with the results
Shown in

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction contents]

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

Front page continuation (72) Inventor Hiroshi Ogiya 32-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa Biopolymer Research Co., Ltd.

Claims (11)

[Claims] 1. A method for drying bacterial cellulose, which comprises adding bacterial cellulose and a third component other than water to an aqueous suspension containing bacterial cellulose, and then dehydrating and drying. 2. The method according to claim 1, wherein the bacterial cellulose has been subjected to disaggregation 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 disaggregation treatment method is mechanical shearing force, ultrasonic wave, high pressure treatment, acid hydrolysis, hydrolysis using an enzyme or a method using 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, squeezing, air drying, hot air drying or vacuum drying, or a combination thereof. 8. The method according to claim 1, wherein bacterial cellulose having a polystyrene-equivalent weight average degree of polymerization of 1.6 × 10 ⁴ or more obtained by aeration and agitation culture is used. 9. The method according to claim 1, wherein bacterial cellulose obtained by static culture and having a polystyrene-equivalent weight-average degree of polymerization of 2.0 × 10 ⁴ or more is used. 10. A dried bacterial cellulose product obtained by the method according to any one of claims 1 to 9. 11. After drying the bacterial cellulose by the method according to any one of claims 1 to 9,
A method for reconstructing a dried bacterial cellulose, which comprises adding water to form a dispersion, stirring and mixing the dispersion, and optionally heat treating the mixture before or after the stirring and mixing.