WO2018038055A1

WO2018038055A1 - Method for producing dry product of dispersible bacterial cellulose and method for producing bacterial cellulose dispersion

Info

Publication number: WO2018038055A1
Application number: PCT/JP2017/029798
Authority: WO
Inventors: 松島　得雄; 健次田島
Original assignee: 草野作工株式会社
Priority date: 2016-08-23
Filing date: 2017-08-21
Publication date: 2018-03-01
Also published as: JPWO2018038055A1

Abstract

[Problem] To provide: a method for producing a dry product of a dispersible bacterial cellulose that is highly dispersible in a liquid; and a method for producing a bacterial cellulose dispersion. [Solution] A method for producing a dry product of a dispersible bacterial cellulose, said method comprising: organic solvent addition step A for adding an organic solvent to a bacterial cellulose dispersion wherein a bacterial cellulose is dispersed in water; and drying step B for removing water and the organic solvent from the bacterial cellulose dispersion containing the organic solvent added thereto and thus drying the bacterial cellulose.

Description

Method for producing dispersible bacterial cellulose dry product and method for producing bacterial cellulose dispersion

TECHNICAL FIELD The present invention relates to a technique for producing highly dispersible bacterial cellulose, and in particular, a method for producing a dispersible bacterial cellulose dried product having a high dispersibility in a liquid and a bacterial cellulose dispersion in which bacterial cellulose is dispersed almost uniformly in a liquid. Regarding the method.

Bacterial cellulose is cellulose produced by bacteria such as acetic acid bacteria, and has high mechanical strength, biocompatibility, biodegradability, etc., and can be used in various industrial fields including cosmetics and pharmaceuticals. It is attracting attention as a material. As described in Patent Document 1, bacterial cellulose is obtained as a bacterial cellulose dispersion in a state of being dispersed in water by culturing bacterial cellulose-producing bacteria by aeration and stirring. However, since this bacterial cellulose dispersion contains a large amount of water, there is a problem that it is expensive to distribute.

In order to solve such a problem, a dry product of bacterial cellulose containing no water is desired. For example, Patent Document 2 discloses a powdered bacterial cellulose preparation (FIG. 9), in addition to bacterial cellulose dispersion. A method for producing a fibrous bacterial cellulose preparation by adding an organic solvent to the liquid, followed by pressure filtration and ventilation drying (paragraph [0137]) is disclosed.

Japanese Patent No. 575332 JP 2014-118498 A

On the other hand, when bacterial cellulose is used as a product material, it is often used in the form of a sol or gel by adding a liquid, so that the dried bacterial cellulose has the property of being uniformly dispersed in the liquid. It is preferable. In this regard, the bacterial cellulose dried product described in Patent Document 1 has not been studied for dispersibility in liquids, and development of a dispersible bacterial cellulose dried product having such properties has been demanded.

The present invention has been made to solve such problems, and is a method for producing a dried bacterial cellulose product having high dispersibility in a liquid, and the bacterial cellulose is dispersed almost uniformly in the liquid. An object is to provide a method for producing a bacterial cellulose dispersion.

As a result of diligent research, the inventors of the present invention produced a dried bacterial cellulose product having high dispersibility in a liquid by adding an organic solvent to the bacterial cellulose dispersion, and subsequently removing the water and the organic solvent and drying them. I found out that I can do it.
Further, after adding a dispersant to the bacterial cellulose dispersion and stirring while heating, an organic solvent is added, and then water and the organic solvent are removed and dried, so that the dispersibility is remarkably high, and The present inventors have found that a dried bacterial cellulose product that does not generate agglomerates upon application can be produced.
It was also found that by adding a dispersant to the bacterial cellulose dispersion and stirring while heating, the bacterial cellulose dispersion can be produced in which the bacterial cellulose is uniformly dispersed and no agglomerates are generated during coating.
Moreover, it discovered that the dispersibility in an organic solvent became remarkably high by combining hydroxypropyl cellulose with the fiber surface of bacterial cellulose.
Furthermore, bacterial cellulose formed by binding hydroxypropyl cellulose by replacing the dispersion medium of the bacterial cellulose dispersion with water from an organic solvent and subsequently removing the dispersion medium and drying the liquid has high dispersibility in the liquid. It has been found that dried bacterial cellulose can be produced.
Accordingly, the following inventions have been completed based on these findings.

(1) A first aspect of the method for producing a dried dispersible bacterial cellulose product according to the present invention includes an organic solvent addition step A in which an organic solvent is added to a bacterial cellulose dispersion obtained by dispersing bacterial cellulose in water, A drying step B in which water and the organic solvent are removed from the bacterial cellulose dispersion added with the organic solvent to dry the bacterial cellulose.

(2) In the method for producing a dispersible bacterial cellulose dried product of (1) above, the bacterial cellulose dispersion to which a dispersant has been added is stirred while being heated to a temperature of more than 45 ° C. before the organic solvent addition step A. It is preferable to have a heating and stirring step A ′.

(3) In the method for producing a dispersible bacterial cellulose dried product according to (2) above, the heating and stirring step A ′ is carried out by subjecting the bacterial cellulose dispersion to which the dispersant has been added to a temperature exceeding 45 ° C. for a time exceeding 15 minutes. The step of stirring is preferable.

(4) In the method for producing a dispersible bacterial cellulose dried product according to (2) or (3) above, the bacterial cellulose dispersion to which the dispersant used in the heating and stirring step A ′ is added is 9 (w / W) A bacterial cellulose dispersion added so as to have a concentration exceeding% is preferable.

(5) In the method for producing a dried dispersible bacterial cellulose product according to any one of (2) to (4) above, the dispersant is one or more selected from the group consisting of carboxymethyl cellulose, hydroxypropyl cellulose, and hydroxyethyl cellulose. It is preferable that

(6) In the first aspect of the method for producing a bacterial cellulose dispersion according to the present invention, a dried bacterial cellulose obtained by removing water and an organic solvent and drying is dispersed in water containing a dispersant. A reconstitution water dispersion step X for preparing a reconstituted bacterial cellulose dispersion, and a reconstitution warming stirring step Y for stirring the reconstituted bacterial cellulose dispersion while heating it to a temperature of more than 45 ° C.

(7) In the method for producing a bacterial cellulose dispersion of (6) above, the regenerating warming stirring step Y is a step of stirring the regenerated bacterial cellulose dispersion at a temperature of more than 45 ° C. for a period of more than 15 minutes. It is preferable.

(8) In the method for producing a bacterial cellulose dispersion according to (6) or (7) above, the dispersant is one or more selected from the group consisting of carboxymethyl cellulose, hydroxypropyl cellulose, and hydroxyethyl cellulose. It is preferable.

(9) The second aspect of the method for producing a bacterial cellulose dispersion according to the present invention includes an organic solvent dispersion step Z in which bacterial cellulose formed by binding hydroxypropyl cellulose is dispersed in an organic solvent.

(10) A second aspect of the method for producing a dried dispersible bacterial cellulose product according to the present invention is a dispersion medium replacement in which a dispersion medium of a bacterial cellulose dispersion obtained by dispersing bacterial cellulose in water is replaced with water from an organic solvent. Step C and a drying step D for removing the dispersion medium from the bacterial cellulose dispersion with the dispersion medium substituted and drying the bacterial cellulose, wherein the bacterial cellulose is a bacterial cellulose formed by binding hydroxypropyl cellulose. is there.

According to the method for producing a dry product of dispersible bacterial cellulose according to the present invention, a dry product of bacterial cellulose can be easily produced, which can contribute to a reduction in the distribution cost of bacterial cellulose. In addition, the dispersible bacterial cellulose dried product produced according to the present invention has high dispersibility in a liquid and is excellent in moldability and miscibility with other substances, so that it can be used as a useful material in various industrial fields. Can do. In addition, when the dispersible bacterial cellulose dried product produced according to the present invention has a property that does not generate agglomerates when applied to the skin or the like in the dispersion, in addition to paints, cosmetics and pharmaceuticals It can be particularly suitably used as the material.

Moreover, according to the method for producing a bacterial cellulose dispersion according to the present invention, a bacterial cellulose dispersion in which bacterial cellulose is dispersed almost uniformly in the liquid can be produced. The bacterial cellulose dispersion produced by the present invention is excellent in moldability and miscibility with other substances, and can be used in various industrial fields. In addition, when the bacterial cellulose dispersion produced by the present invention also has a property that does not generate agglomerates when applied to the skin or the like, it is particularly suitable as a material for cosmetics and pharmaceuticals in addition to paints. Can be used.

1 is a table showing the state of dispersion of dried bacterial cellulose (BC dried product) produced by changing the final concentration of carboxymethyl cellulose (CMC) and the presence or absence of agglomerates during skin application. II of FIG. 1 is a photograph showing a state of dispersion of a dried BC product produced by changing the final concentration of CMC at a restoration time of 60 minutes. I in FIG. 2 is a table showing the state of dispersion of the dried BC product produced by changing the stirring temperature and stirring time, and the presence or absence of the generation of agglomerates during skin application. II of FIG. 2 is a photograph showing a state of dispersion of a dried BC product produced by changing the stirring temperature and stirring time. FIG. 3I is a table showing the filterability, dispersion state, and presence / absence of agglomerates during skin application of the dried BC product produced by changing the amount of ethanol added. II in FIG. 3 is a photograph showing a state of dispersion of a dried BC product produced by changing the amount of ethanol added. I in FIG. 4 is a table showing the state of dispersion of the dried BC product produced by changing the drying temperature. II of FIG. 4 is a photograph showing a state of dispersion of a dried BC product produced by changing the drying temperature at a restoration time of 90 minutes. It is a graph which shows the ratio of the various dispersing agent couple | bonded with bacterial cellulose (BC). It is the spectrum of infrared spectroscopy (IR) of BC which various dispersing agents combined. It is the photograph which observed the BC which various dispersing agents couple | bonded with the transmission electron microscope. The numerical value in the lower part of the photograph is the cellulose fiber width (average value) of the BC. FIG. 8I is a table showing the state of dispersion in various dispersion media for BC to which various dispersants are bonded. II of FIG. 8 is the photograph which observed the said BC in various dispersion media with the polarizing microscope. It is a photograph which shows the mode of dispersion | distribution in various dispersion media about BC which the various dispersing agent couple | bonded. FIG. 10I shows the state of BC dispersion in a BC dispersion liquid (comparative control) to which hydroxypropyl cellulose (HPC) is bound, and a dispersion liquid (restored BC dispersion liquid) in which the dry product of BC is dispersed. It is a photograph shown. II in FIG. 10 is a graph showing the light transmittance at a wavelength of 500 nm.

Hereinafter, a method for producing a dried dispersible bacterial cellulose product and a method for producing a bacterial cellulose dispersion according to the present invention will be described in detail.

In the present invention, “bacterial cellulose dried product” refers to bacterial cellulose that has been subjected to a treatment for removing liquid components such as water and organic solvents. That is, as a result of the removal process of the liquid component, the bacterial cellulose in which the liquid component remains to some extent is also included in the “bacterial cellulose dried product”.
In the present invention, the “dispersed bacterial cellulose dried product” refers to a dried bacterial cellulose product having a high dispersibility in a liquid.

In the present invention, the term “bacterial cellulose dispersion” refers to a liquid containing bacterial cellulose and present in a state where bacterial cellulose is dispersed in the liquid.

Here, in the present invention, “dispersing” bacterial cellulose in a liquid means that the bacterial cellulose is suspended or suspended in the liquid.
“High dispersibility” means that the particle size and fiber width in the liquid (dispersion medium) of bacterial cellulose as a dispersoid are relatively small, or the bacterial cellulose as a dispersoid is in the liquid (dispersion medium). It means that it is suspended or suspended relatively uniformly.
On the other hand, “low dispersibility” means that the particle size and fiber width in the liquid (dispersion medium) of bacterial cellulose as a dispersoid is relatively large, or the bacterial cellulose as a dispersoid is in the liquid (dispersion medium). It means that it is relatively non-uniformly suspended or suspended, and that bacterial cellulose is unevenly distributed, precipitated, aggregated, etc. in the liquid (dispersion medium).

The first aspect of the method for producing a dispersible bacterial cellulose dry product according to the present invention includes:
Organic solvent addition step A; adding an organic solvent to a bacterial cellulose dispersion obtained by dispersing bacterial cellulose in water;
Drying step B; a step of drying bacterial cellulose by removing water and organic solvent from the bacterial cellulose dispersion to which the organic solvent has been added;
The above steps A and B are included.

The “bacterial cellulose dispersion in which bacterial cellulose is dispersed in water” according to the present invention is, for example, bacterial cellulosic bacteria produced by stirring culture or aeration culture, and removing bacterial cell components from the obtained culture liquid. Can be obtained by purification.

Here, as the bacterial cellulose-producing bacteria, known bacteria capable of producing bacterial cellulose can be used, and specifically, for example, Gluconacetobacterｌxylinus ATCC53582 strain, Gluconacetobacter hansenii ATCC23769 strain, and GluconacetobacterＰＲBlAT8C7lin8 strain7PR7 , Gluconacetobacter swingsii BPR3001E strain, Acetobacter xylinum JCM10150 strain, Enterobacter sp. CJF-002 strain, Gluconacetobacterium intermediaus SIID9587 strain (Accession number NITE BP-01495) and the like can be used.

The culture conditions for bacterial cellulose-producing bacteria can be known culture conditions used for culturing the above-mentioned bacteria. For example, the aeration rate is 1 to 10 L / min, the rotation speed is 100 to 800 rpm, the temperature is 20 to 40 ° C. Examples include culture conditions for a period of 1 to 7 days. As the medium, a known medium used for culturing the above-mentioned bacteria such as a Hestrin-Schram standard medium can be used.

As a method for purifying bacterial cellulose by removing bacterial cell components from a culture solution in which bacterial cellulose-producing bacteria are cultured, first, an aqueous solution of sodium hydroxide (NaOH) is added to the culture solution and heated to about 60 ° C. The cells are dissolved by shaking for a long time. This is subjected to centrifugation, and the cell components are removed by removing the supernatant, and the precipitate is collected. Subsequently, after adding water to the precipitate and centrifuging it, a method of repeatedly removing the supernatant until the pH of the precipitate becomes 7 or less can be mentioned.

In the “bacterial cellulose dispersion in which bacterial cellulose is dispersed in water” in the organic solvent addition step A, the concentration of bacterial cellulose is not particularly limited, but as shown in Example 4 to be described later, In the dispersion, the concentration is preferably less than 1.0 (w / w)% from the viewpoint of suppressing the generation of agglomerates during coating.

“Organic solvent” refers to an organic compound that is liquid at normal temperature and pressure. In general, organic solvents are roughly classified into those having low polarity and those having medium / high polarity, and any of these may be used, but those having medium / high polarity are more preferable. Specific examples of the medium / high polarity organic solvent include ethanol, methanol, isopropyl alcohol, acetone, ethyl acetate, tetrahydrofuran, N, N-dimethylformamide (DMF), acetonitrile, tert-butyl alcohol, dimethyl sulfoxide ( DMSO), dichloromethane, diethyl ether and the like.

The addition amount of the organic solvent in the organic solvent addition step A is not particularly limited, but as shown in Example 5 described later, the effect of facilitating the production of the dried bacterial cellulose and the liquid of the produced dried bacterial cellulose In terms of the effect of improving the dispersibility in the composition and suppressing the generation of agglomerates during coating, the amount is preferably more than 0.5 times the amount of the bacterial cellulose dispersion, and more than 1.0 times the amount of the bacterial cellulose dispersion. More preferred.

In the first aspect of the method for producing a dispersible bacterial cellulose dried product according to the present invention, as shown in Example 1 described later, the dispersibility of the produced bacterial cellulose dried product in a liquid is increased and applied. It is preferable to have the following heating and stirring step A ′ before the organic solvent addition step A in terms of the effect of suppressing the generation of agglomerates.
Heating and stirring step A ′; a step of stirring the bacterial cellulose dispersion added with the dispersant while heating to a temperature of more than 45 ° C.

Here, the heating and stirring step A ′ is a step of stirring while heating until the bacterial cellulose is almost uniformly dispersed in the liquid. As temperature for making it into the said state, the temperature over 45 degreeC can be mentioned, for example, 50 degreeC or more is more preferable. Moreover, as time to stir at the said temperature, 5 minutes or more can be mentioned, for example, 15 minutes or more are preferable and 30 minutes or more are more preferable.
By such treatment, the dispersing agent binds to the bacterial cellulose, promotes the dispersion of the bacterial cellulose in the liquid, and can suppress the generation of agglomerates during application.

In the “bacterial cellulose dispersion added with the dispersant” in the heating and stirring step A ′, the concentration of the dispersant is not particularly limited. However, in terms of the effect of increasing the dispersibility of the produced dried bacterial cellulose in the liquid, 2 It is preferable that it is (w / w)% or more. In addition, the concentration of the dispersant is more than 9 (w / w)% in terms of the effect of improving the dispersibility of the dried bacterial cellulose product in the liquid and suppressing the generation of agglomerates during coating. It is preferable that the concentration is 14% or more.
The concentration of the dispersant refers to the concentration of all the dispersants contained in the bacterial cellulose dispersion regardless of whether or not it is bound to the bacterial cellulose.

In the present invention, “dispersant” refers to a substance that binds to bacterial cellulose and improves the dispersibility of bacterial cellulose in a liquid. Specifically, carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), hydroxy Examples thereof include propylcellulose (HPC) and carboxymethyl chitin. As shown in Example 8 to be described later, in terms of the effect of improving the dispersibility of bacterial cellulose in water, a dispersant of cellulose derivatives such as CMC, HEC, and HPC is preferable, and the effect of improving the dispersibility in an organic solvent. Of these, HPC is preferred among these.

As a method of drying bacterial cellulose by removing water and the organic solvent from the bacterial cellulose dispersion added with the organic solvent in the drying step B, for example, the bacterial cellulose dispersion added with the organic solvent is subjected to filtration and filtered. Can be collected and dried. In this case, examples of the filtration method include natural filtration, vacuum filtration, pressure filtration, squeeze filtration, and centrifugal filtration. Examples of the drying method include heat drying, ventilation drying, freeze drying, and spray drying.

The drying method may be a method in which the bacterial cellulose dispersion added with the organic solvent is subjected to heat drying, ventilation drying, freeze drying, spray drying, or the like without performing the above-described filtration.

In the drying step B, the temperature for heating and drying the bacterial cellulose is 105 ° C. in terms of the effect of increasing the dispersibility of the produced dried bacterial cellulose in the liquid, as shown in Example 6 described later. Drying at a lower temperature is preferable, and drying at a temperature of 80 ° C. or lower is more preferable.

Next, the second aspect of the method for producing a dried dispersible bacterial cellulose product according to the present invention includes:
Dispersion medium replacement step C; a step of replacing the dispersion medium of the bacterial cellulose dispersion obtained by dispersing bacterial cellulose in water with an organic solvent,
A drying step D; a step of removing the dispersion medium from the bacterial cellulose dispersion in which the dispersion medium has been substituted and drying the bacterial cellulose;
It has the process of C and D above. In the second aspect, the description of the same or corresponding configuration as the first aspect described above is omitted.

As a method of replacing the dispersion medium of the bacterial cellulose dispersion in which the bacterial cellulose is dispersed in water in the dispersion medium replacement step C, the bacterial cellulose dispersion is subjected to centrifugation and the supernatant is removed. There can be mentioned a method in which an equivalent amount of an organic solvent is added and suspended, and then subjected to centrifugation again to remove the supernatant several times. In the present step C, the bacterial cellulose dispersion in which the dispersion medium is replaced may be that most of the dispersion medium is an organic solvent, and a small amount of water may remain.

As a method of drying the bacterial cellulose by removing the dispersion medium from the bacterial cellulose dispersion in which the dispersion medium is substituted in the drying step D, the same method as the drying step B in the first aspect described above can be exemplified.

The method for producing a dried bacterial cellulose according to the present invention may further include other steps as long as the characteristics of the present invention are not impaired. Examples of such steps include a step for culturing bacterial cellulose-producing bacteria, Examples include a purification process of bacterial cellulose, a preparation process of a bacterial cellulose dispersion, and a pulverization process of a dried bacterial cellulose.

Next, the present invention provides a method for producing a bacterial cellulose dispersion. A first aspect of the method for producing a bacterial cellulose dispersion according to the present invention is a method for producing a bacterial cellulose dispersion using water as a dispersion medium,
Recovery water dispersion step X: A step of preparing a restored bacterial cellulose dispersion by dispersing a dried bacterial cellulose obtained by removing water and an organic solvent and drying in water containing a dispersant,
Heating and stirring step for restoration Y: Step of stirring the restored bacterial cellulose dispersion while heating to a temperature of more than 45 ° C.,
It has the process of X and Y above. In addition, in the 1st aspect of the manufacturing method of the bacterial cellulose dispersion which concerns on this invention, description is abbreviate | omitted again about the structure similar to or equivalent to the manufacturing method of the dispersible bacterial cellulose dried material mentioned above.

The “bacterial cellulose dried product obtained by removing water and organic solvent and drying” in the water dispersion step X for restoration refers to removing a dispersion medium from a bacterial cellulose dispersion containing water and / or an organic solvent as a dispersion medium. Refers to dried bacterial cellulose. Such dried bacterial cellulose can be obtained by the same method as in the drying step B described above.

In the restoration water dispersion step X, “water containing a dispersant” refers to water to which a dispersant has been added to a predetermined concentration. Here, the concentration of the dispersant in the water is not particularly limited, but is preferably 4 (w / w)% or more in terms of the effect of enhancing the dispersibility of the bacterial cellulose. In terms of the effect of enhancing the dispersibility of bacterial cellulose and suppressing the generation of agglomerates during coating, the concentration of the dispersant is preferably more than 9 (w / w)%, and 14% More preferable is the above concentration.

As a method of dispersing the dried bacterial cellulose in water containing a dispersant in the water dispersion step X for restoration, for example, after adding water containing a dispersant to the dried bacterial cellulose and allowing it to stand for a predetermined time In addition, a method of mixing or suspending by a conventional method such as pipetting, vortexing, or shaking can be used.
The amount of water containing the dispersant can be set according to the desired bacterial cellulose concentration in the bacterial cellulose dispersion, for example, the bacterial cellulose concentration is 0.5 to 2.0 (w / w)%. Or the like.
Further, the standing time after adding the water containing the dispersant can be appropriately set according to the concentration of the dispersant, the concentration of bacterial cellulose, etc., for example, 30 minutes to 24 hours. it can.

The regenerating warming stirring step Y is a step of stirring while heating until the bacterial cellulose in the reconstituted bacterial cellulose dispersion is almost uniformly dispersed in the liquid. As temperature for making it into the said state, the temperature over 45 degreeC can be mentioned, for example, 50 degreeC or more is more preferable. Moreover, as time to stir at the said temperature, 5 minutes or more can be mentioned, for example, 15 minutes or more are preferable and 30 minutes or more are more preferable.
By such treatment, the dispersing agent binds to the bacterial cellulose, promotes the dispersion of the bacterial cellulose in the liquid, and can suppress the generation of agglomerates during application.

Finally, a second aspect of the method for producing a bacterial cellulose dispersion according to the present invention is a method for producing a bacterial cellulose dispersion using an organic solvent as a dispersion medium,
Organic solvent dispersion step Z: a step of dispersing bacterial cellulose formed by binding hydroxypropylcellulose in an organic solvent. The second aspect of the method for producing a bacterial cellulose dispersion according to the present invention is the same as or corresponding to the first aspect of the method for producing a dried dispersible bacterial cellulose and the method for producing a bacterial cellulose dispersion described above. As for, the repeated explanation is omitted.

In the organic solvent dispersion step Z, “bacterial cellulose formed by binding hydroxypropyl cellulose (HPC-bonded BC)” may be in the form of a dispersion in which HPC-bonded BC is dispersed in water, or in a dry product state. Also good.
For example, the HPC-bound BC in a dispersion state is obtained by stirring and aeration culture of bacterial cellulose-producing bacteria under the above-described culture conditions using a medium supplemented with HPC, and removing cell components from the obtained culture liquid. It can be obtained by purifying bacterial cellulose. In this case, the HPC concentration in the medium may be, for example, 0.2 to 2.0 (w / w)%.
Further, the HPC-bound BC in a dried state can be obtained by drying the dispersion of the HPC-bound BC obtained as described above by a method such as heat drying, ventilation drying, freeze drying, or spray drying.

As a method of dispersing the HPC-bonded BC in the organic solvent in the organic solvent dispersion step Z, for example, if the HPC-bonded BC is in a dispersion state, the solvent replacement method described above for the dispersion medium replacement step C (the organic solvent is changed). In addition, an operation of suspending and removing the supernatant by centrifugation is repeated several times.
In addition, in the case of HPC-bound BC in a dried state, a method of adding or dissolving an organic solvent and mixing or suspending by a conventional method such as pipetting, vortexing or shaking can be mentioned.
The addition amount of the organic solvent can be set according to the desired bacterial cellulose concentration in the bacterial cellulose dispersion, for example, an amount that gives a bacterial cellulose concentration of 0.5 to 2.0 (w / w)%, etc. can do.

The method for producing a bacterial cellulose dispersion according to the present invention may have other steps as long as the characteristics of the present invention are not impaired. Examples of such steps include a step for culturing bacterial cellulose-producing bacteria, Examples include bacterial cellulose purification steps.

Hereinafter, the manufacturing method of the dispersible bacterial cellulose dried product and the manufacturing method of the bacterial cellulose dispersion according to the present invention will be described based on each example. Note that the technical scope of the present invention is not limited to the features shown by these examples.

In the following examples, the production of bacterial cellulose (BC) includes Hestrin-Schramm standard medium (HS medium, composition; bacto pepton 0.5 (w / v)%, yeast extract 0.5 ( w / v)%, Na ₂ HPO ₄ 0.27 (w / v)%, citric acid 0.115 (w / v)%, glucose 2 (w / v)%).
The BC concentration in the liquid was measured by a 105 ° C. drying method. That is, first, a certain amount of sample (bacterial cellulose dispersion) is taken, and the mass is measured. Subsequently, the sample is put in a drier and heated and dried at 105 ° C. for 4 hours or more. After allowing to cool, the mass of the dried product was measured, and the concentration by mass was calculated based on these measured values.

<Example 1> Production of dried BC (1) Production of BC 400 μL of a suspension of Gluconacetobacter xylinus ATCC 53582, a bacterial cellulose-producing bacterium, was added to 10 mL of HS medium and left to stand at 30 ° C. for 3 days. This was used as a culture medium in advance. Next, 1 mL of the previous culture solution was added to 10 mL of a new HS standard medium, and static culture was performed at 30 ° C. for 3 days, which was used as a preculture solution. 2.0 g of carboxymethylcellulose (CMC; Wako Pure Chemical Industries, Ltd.) was added to 100 mL of a new HS standard medium. Bacterial cellulose (BC) is obtained by adding 5 mL of the preculture solution and performing aeration and agitation culture for 3 days under the conditions of an aeration rate of 7 to 10 L / min, a rotation speed of 150 rpm, and a temperature of 30 ° C. (main culture). Produced.

Subsequently, the culture solution after the main culture was centrifuged (8000 rpm, 15 minutes), and the precipitate was collected. 1 (w / v)% NaOH aqueous solution was added 5 times the volume of the precipitate, and the cells were dissolved by shaking at 70 ° C. and 100 rpm for 2 hours. Thereafter, this was subjected to centrifugation under the same conditions, and the supernatant was removed to collect the precipitate, thereby removing water-soluble bacterial cell components. After the ultrapure water was added to the solution and centrifuged under the same conditions, the supernatant was removed and repeated until the pH of the precipitate was 7 or less in a wet state to purify BC. A liquid containing BC was used as a BC dispersion.

(2) Production of BC dried product Water was added to the BC dispersion of Example 1 (1) to adjust the BC concentration to 0.7 (w / w)%. This BC dispersion contained 2 (w / w)% or more of CMC (CMC bound to BC) derived from the medium during BC production. This was dispensed to set three samples (ac). Among them, sample a was subjected to the following steps (i) to (iii) to produce a dry BC product.

<< Manufacturing Process of BC Dry Material >>
(i) CMC was added to the BC dispersion so that the final concentration was 20 (w / w)%, and the mixture was stirred at 55 ° C. for 30 minutes.
(ii) 1.5 times the amount of ethanol was added to the BC dispersion and stirred for 10 minutes.
(iii) Circular qualitative filter paper No. The water and ethanol were removed by suction filtration at 0.06 MPa using No. 1 (ADVANTEC), and the obtained residue was dried at 60 ° C. for 60 minutes.

On the other hand, for sample b, a dry BC product was produced by the steps (ii) and (iii) without performing the step (i). About sample c, BC dried material was manufactured by making it dry for 60 minutes at 80 degrees C or less.

(3) Restoration of BC dispersion Water is added to the BC dried product of Example 1 (2) so that the BC concentration becomes 0.7 (w / w)%, and the mixture is allowed to stand for 60 minutes and then pipetted. As a result, BC was dispersed to obtain a restored BC dispersion. The state of BC dispersion in the restored BC dispersion was observed. In addition, the restored BC dispersion was applied to the skin, and the presence or absence of agglomeration was observed. The results are shown in Table 1.
In the following examples, the degree of BC dispersion in the restored BC dispersion is indicated by the number of “+” according to the following criteria. Criteria for evaluating dispersibility:-: Not dispersible, +: Low dispersibility, ++: Slightly dispersible, +++: Slightly dispersible, +++++: Grains but high dispersibility, +++++: Dispersible high.

As shown in Table 1, the dried BC (sample c) obtained by drying the BC dispersion was not dispersed in water. Moreover, since the sample c did not disperse | distribute in water, the skin application | coating test was not performed (NT). In contrast, the dried BC product (sample a) produced by the steps (i) to (iii) and the dried BC product (sample b) produced by the steps (ii) and (iii) are both Dispersibility in water was high. In addition, the BC dried product (sample a) produced by the steps (i) to (iii) had a remarkably high dispersibility, and no agglomerates were generated when applied to the skin.

From these results, it was clarified that a BC dried product having high dispersibility in a liquid can be produced by adding an organic solvent to the BC dispersion, and subsequently removing the water and the organic solvent and drying. In addition, after the BC dispersion containing the dispersant is heated and stirred, an organic solvent is added, and then water and the organic solvent are removed and dried. It became clear that BC dry substance which does not generate | occur | produce a grain can be manufactured.

<Example 2> Production of dried BC; Examination of final concentration of dispersant Using the BC dispersion liquid of Example 1 (1), steps (i) to (iii) described in Example 1 (2) BC dry product was produced. However, the final concentration of CMC in step (i) is 4 (w / w)%, 9 (w / w)%, 14 (w / w)%, 19 (w / w)% and 24 (w / w). )%. Thereafter, the dried BC product was dispersed in water by the method described in Example 1 (3) to obtain a restored BC dispersion. However, the standing time (restoration time) after adding water to the BC dried product was changed to 0 minutes, 10 minutes, 60 minutes, and 24 hours instead of 60 minutes, and the dispersion of BC in the restored BC dispersion liquid at each time. The state of was observed. Moreover, the presence or absence of agglomeration at the time of skin application was observed with respect to a restoration time of 24 hours. The results are shown in I and II of FIG.

As shown in I and II of FIG. 1, the final concentrations of CMC were 4 (w / w)%, 9 (w / w)%, 14 (w / w)%, 19 (w / w)% and 24 ( The BC dried product produced as w / w)% was highly dispersible in water when the restoration time was 60 minutes or more. In addition, the dried BC product produced with a final CMC concentration of 14 (w / w)%, 19 (w / w)%, and 24 (w / w)% has a remarkably high dispersibility and is applied to the skin. Almost no agglomerates were generated.

From these results, it became clear that by using a BC dispersion liquid containing a dispersant at a concentration of 4 (w / w)% or more, a BC dry product having high dispersibility in the liquid can be produced. Moreover, it is clear that by using a BC dispersion liquid containing a dispersant at a concentration of more than 9 (w / w)%, it is possible to produce a dry BC product that has a remarkably high dispersibility and does not generate agglomerates during coating. Became.

<Example 3> Production of dried BC; Examination of temperature and stirring time during stirring Steps (i) to (iii) described in Example 1 (2) using the BC dispersion liquid of Example 1 (1) ) Produced BC dry product. However, the final concentration of CMC in step (i) is 19 (w / w)%, and the temperature during stirring (stirring temperature) is 25 ° C, 45 ° C, 55 ° C, 65 ° C and 80 ° C instead of 55 ° C. It was. In addition, the stirring time (stirring time) in the step (i) was set to 0 minutes, 15 minutes, 30 minutes, and 60 minutes instead of 30 minutes. Thereafter, the dried BC product was dispersed in water by the method described in Example 1 (3), and the state of BC dispersion in the restored BC dispersion was observed. Moreover, about the dry BC product which made stirring time 60 minutes, the presence or absence of the lump generation | occurrence | production at the time of skin application | coating in the decompression | restoration BC dispersion was observed. The results are shown in I and II of FIG.

As shown in I and II of FIG. 2, the dried BC product with a stirring temperature of 25 ° C. or 45 ° C. did not disperse in water, and agglomerates were generated when the skin was applied. Moreover, the BC dried product with a stirring time of 0 or 15 minutes had low dispersibility in water. On the other hand, a dry BC product having a stirring temperature of 55 ° C., 65 ° C. or 80 ° C. and a stirring time of 30 minutes or 60 minutes has high dispersibility in water and has no lump when applied to the skin. Did not occur.

From these results, a BC dispersion containing a dispersant is stirred at a temperature of more than 45 ° C. to produce a dry BC product that has a remarkably high dispersibility in the liquid and does not generate agglomerates during coating. It became clear that we could do it. This is because the dispersion of the BC dried product is promoted by binding the BC to the BC by stirring the BC dispersion containing the dispersant in a temperature zone heated to a predetermined temperature or higher. The present inventors believe that this is the case.

<Example 4> Manufacture of dried BC; Examination of BC concentration in BC dispersion Steps (i) to (iii) described in Example 1 (2) using the BC dispersion of Example 1 (1) A BC dry product was produced by the above method. However, the BC concentration of the BC dispersion in step (i) is 0.5 (w / w)%, 0.7 (w / w)% and 1.0 instead of 0.7 (w / w)%. (W / w)%. Thereafter, a restored BC dispersion was obtained by the method described in Example 1 (3), and the state of BC dispersion and the presence or absence of agglomerates during skin application were observed. The results are shown in Table 2.

As shown in Table 2, the BC dried product produced with the BC concentration in the BC dispersion as 0.5 (w / w)%, 0.7 (w / w)% and 1.0 (w / w)% Both were highly dispersible in water. In addition, in the BC dried product produced with a BC concentration of 0.5 (w / w)% and 0.7 (w / w)%, no lump was generated when the skin was applied.

From these results, regardless of the BC concentration in the BC dispersion, the BC dispersion containing the dispersant is stirred while heating, and then an organic solvent is added, followed by removing water and the organic solvent and drying. Thus, it became clear that a BC dried product having high dispersibility in a liquid can be produced. Moreover, it became clear that the BC dry substance which does not generate | occur | produce a lump at the time of application | coating can be manufactured by making BC concentration in BC dispersion liquid less than 1.0 (w / w)%.

<Example 5> Production of dried BC; Examination of addition amount of organic solvent Using the BC dispersion liquid of Example 1 (1), the steps (i) to (iii) described in Example 1 (2) A BC dry product was produced. However, the stirring temperature in the step (i) was set to 65 ° C. instead of 55 ° C. The amount of ethanol added in step (ii) is 0.5 times, 1 time and 1.5 times the amount of BC dispersion instead of 1.5 times the amount of BC dispersion, and step (iii) Filterability (easy removal of water and ethanol by suction filtration) was confirmed. Thereafter, a restored BC dispersion was obtained by the method described in Example 1 (3), and the state of BC dispersion and the presence or absence of agglomerates during skin application were observed. The results are shown in I and II of FIG.

As shown in I of FIG. 3, when the amount of ethanol added was 0.5 times the amount of the BC dispersion, filterability was poor and it was difficult to remove moisture and ethanol by suction filtration. When the amount of ethanol added was 1.0 and 1.5 times that of the BC dispersion, the filterability was good and water and ethanol could be easily removed by suction filtration.
In addition, as shown in I and II of FIG. 3, the BC dried product produced by adding 0.5% of the amount of ethanol added to the BC dispersion does not disperse in water, and agglomerates are generated when applied to the skin. On the other hand, the dried BC product produced by adding ethanol in an amount 1.0 and 1.5 times that of the BC dispersion is highly dispersible in water, and is agglomerated when applied to the skin. Did not occur.

From these results, by making the addition amount of the organic solvent more than 0.5 times the amount of the BC dispersion, it is possible to easily produce a BC dry product, and the dispersibility in the liquid is high, and It became clear that a BC dried product which does not generate agglomerates during application can be produced.

<Example 6> Production of BC dried product; Examination of drying temperature BC dried product according to steps (i) to (iii) described in Example 1 (2) using the BC dispersion liquid of Example 1 (1) Manufactured. However, the BC concentration of the BC dispersion in step (i) was 0.67 (w / w)%, and the stirring temperature was 65 ° C. instead of 55 ° C. Moreover, the temperature (drying temperature) for drying the filtrate in step (iii) was set to 65 ° C., 80 ° C. and 105 ° C. instead of 60 ° C. Thereafter, a restored BC dispersion was obtained by the method described in Example 1 (3). However, the standing time (restoration time) after adding water to the BC dried product was changed to 0 minutes, 30 minutes, 60 minutes, and 90 minutes instead of 60 minutes, and the BC dispersion in the restored BC dispersion at each time. The state of was observed. The results are shown in I and II of FIG.

As shown in I and II of FIG. 4, the BC dried product with a drying temperature of 105 ° C. did not disperse in water during any restoration time. On the other hand, the BC dried product having a drying temperature of 65 ° C. and 80 ° C. was remarkably high in dispersibility in water at the restoration times of 30, 60 and 90 minutes. From these results, it became clear that a BC dried product having remarkably high dispersibility in a liquid can be produced by setting the temperature for drying BC to 80 ° C. or lower.

Example 7 Production of BC Dispersion CMC was added to the restored BC dispersion of sample b of Example 1 (3) to a final concentration of 20 (w / w)%, and then at 55 ° C. for 30 minutes. Stirring was performed, and the obtained restored BC dispersion was designated as sample b ′. With respect to the restored BC dispersion of sample b and sample b ′, the state of BC dispersion and the presence or absence of agglomerates during skin application were observed. The results are shown in Table 3.

As shown in Table 3, the reconstituted BC dispersion of sample b ′ had higher BC dispersibility than the reconstituted BC dispersion of sample b, and no agglomerates were generated during skin application.
From this result, the BC dried product is dispersed in water containing a dispersant and then stirred while warming, whereby BC is dispersed almost uniformly in water and no agglomerates are generated during coating. It became clear that a BC dispersion could be produced.

<Example 8> Examination of Dispersant (1) Production of BC As a dispersant, 2 types of CMC (CMC-1 and CMC-2) and 3 types of HEC (HEC-1, HEC-2, HEC) -3) and 3 types of HPC (referred to as HPC-1, HPC-2, and HPC-3), BC was produced by the method described in Example 1 (1). Obtained. Table 4 shows the dispersant used. However, the bacterial cellulose-producing bacterium is Gluconacetobacter intermedius SIID9587 strain (Accession number NITE BP-01495; As a comparative control, BC was produced in the same manner without using a dispersant to obtain a BC dispersion.

(2) Quantification of binding amount of dispersing agent Among the BC dispersion liquids of Example 8 (1), those produced using a dispersing agent were prepared and freeze-dried to obtain a dried BC product. An absolute dry state was obtained by placing 30 mg of a dried BC product at 105 ° C. for 5 hours. After cooling to room temperature with a desiccator, 3 mL of a 60 (w / w)% tetrabutylphosphonium hydride (TBPH) aqueous solution was added and stirred at 70 ° C. for about 2 hours to completely dissolve BC. Subsequently, 50 mL of water was added to precipitate only cellulose. The precipitate was removed by filtration and the aqueous solution was recovered. This aqueous solution contains a dispersant bonded to BC. The aqueous solution was subjected to vacuum filtration to collect the residue, dried at 70 ° C. for 1 hour, and then weighed. Based on the measurement result, the ratio ((w / w)%) of the weight of the dispersant to the weight of the dried BC was calculated. The result is shown in FIG.

As shown in FIG. 5, the weight ratio of CMC-1, CMC-2, HEC-1, HEC-2, HEC-3, HPC-1, HPC-2 and HPC-3 in the dried BC is Was 10 (w / w)% or more. From this result, it became clear that all of the dispersants of CMC, HEC and HPC are bound to BC in a considerable amount.

(3) Structural analysis of BC bound with dispersing agent Among the BC dispersing liquids of Example 8 (1), those produced using CMC-2, HEC-3 and HPC-3 as the dispersing agent were prepared according to a conventional method. Infrared spectroscopy (IR) spectra were obtained and analyzed. The result is shown in FIG.

As shown in FIG. 6, in BC produced using HPC-3, a peak was observed at 2950 to 2850 cm ⁻¹ indicating a methyl group (—CH ₃ ). In addition, in the BC produced using HPC-3 and the BC produced using HEC-3, the peak at 2900-2800 cm ⁻¹ indicating a methylene group (—CH ₂ —) was large. In BC produced using CMC-2, a peak was observed at 1599 cm ⁻¹ indicating a carboxyl group (—COOH). On the other hand, in the BC produced without using a dispersant, the methyl group peak and the carboxyl group peak were not observed, and the methylene group peak was small. From these results, it was revealed that all the dispersants of CMC, HEC and HPC were bound to BC.

(4) Measurement of the fiber width of BC bonded with a dispersant Among the BC dispersion liquids of Example 8 (1), those produced using CMC-2, HEC-3 and HPC-3 as the dispersant were prepared. did. After adjusting the cellulose concentration to about 0.002 (w / w)%, 5 μL each was dropped on a formbar-coated copper grid together with the dissociation solution and dried at 30 ° C. Subsequently, 2 μL of 3 (w / v)% gadolinium acetate aqueous solution was dropped, and excess liquid was removed with a filter paper, and then 5 μL of ultrapure water was added. Using a transmission electron microscope, observation was performed at an acceleration voltage of 80 kV and an observation magnification of 80,000 times, and the width of the cellulose fiber was measured based on the observation image. The result is shown in FIG.

As shown in FIG. 7, the width (average value) of cellulose fibers was 28.55 nm for BC produced using CMC-2, 34.76 nm for BC produced using HEC-3, and HPC-3 was used. The BC produced was 47.18 nm, and was significantly smaller than the 63.74 nm BC produced without using a dispersant. From this result, it became clear that the fibers of BC can be thinned by combining a dispersant such as CMC, HEC, and HPC.

(5) Evaluation of dispersibility in an organic solvent Of the BC dispersion liquid of this Example 8 (1), a dispersion produced using CMC-2, HEC-3 and HPC-3 as a dispersant was prepared. The BC concentration was adjusted to 0.2 (w / w)% by adding water. 1 mL of this was added to an Eppendorf tube and centrifuged (25 ° C., 15000 rpm, 1 minute) to remove the supernatant. Subsequently, 1 mL of various organic solvents (methanol, isopropyl alcohol, acetone, ethyl acetate, tetrahydrofuran, N, N-dimethylformamide and acetonitrile) are added and suspended by pipetting, and then centrifuged under the same conditions. Qing was removed. By repeating this operation three times, the dispersion medium was replaced from water to an organic solvent.

Subsequently, visual observation and observation with a polarizing microscope were performed, and the state of BC dispersion in an organic solvent was observed. Further, based on the observation result with a polarizing microscope, the degree of dispersion of BC in an organic solvent is classified into three stages (◯: completely dispersed, Δ: partially aggregated but dispersed, × ; Agglomerated). The observation result with a polarizing microscope is shown in FIG. 8, and the visual observation result is shown in FIG. As a comparative control, the results of a BC dispersion using water as a dispersion medium are also shown.

As shown in FIGS. 8 and 9, BC bonded with CMC-2 was highly dispersible in water and methanol, and relatively high in N, N-dimethylformamide. BC bound with HEC-3 was highly dispersible in water, methanol and N, N-dimethylformamide, and was relatively dispersible in tetrahydrofuran. In contrast, BC bound with HPC-3 was highly dispersible in all of water, methanol, isopropyl alcohol, acetone, ethyl acetate, tetrahydrofuran, N, N-dimethylformamide and acetonitrile. From this result, it has been clarified that BC formed by combining HPC has significantly increased dispersibility in not only water but also an organic solvent.

<Example 9> Manufacture of a dried product of BC bonded with HPC (1) Manufacture of a dried product of BC Among the BC dispersion liquid of Example 8 (1), a product produced using HPC-3 was prepared, and water was prepared. Was added to adjust the BC concentration to 0.1 (w / w)%. Some of these were set aside as “comparison controls”. The remaining BC dispersion was divided into two equal parts, which were designated as sample p and sample q. The dispersion medium of sample p was substituted from water to tert-butyl alcohol by the method described in Example 8 (5). In sample q, the dispersion medium was left as water. These were freeze-dried to obtain a dried BC product.

(2) Restoration of BC dispersion Water was added to the dried BC product (samples p and q) of Example 9 (1) so that the BC concentration was 0.1 (w / w)%, and vortex mixer was used. The BC was dispersed by stirring to obtain a restored BC dispersion.

The state of BC dispersion in the restored BC dispersion was visually observed. As a result, in sample p, BC was almost uniformly dispersed in water. On the other hand, in sample q, BC was in an aggregated state and was hardly dispersed in water. From this result, it is clarified that, by replacing the dispersion medium of the BC dispersion liquid with water and then drying, a BC dry product having high dispersibility in the liquid can be produced for BC combined with HPC. It was.

(3) Confirmation of Permeability of Restored BC Dispersion Liquid The BC concentration of the comparative BC dispersion liquid of Example 9 (1) and the restored BC dispersion liquid (Sample p) of Example 9 (2) was reduced to 0 by adding water. Adjusted to 1 (w / w)%. 1 mL of this was added to the cell, and the transmittance of light having a wavelength of 500 nm was measured using a spectrophotometer (U-2001 type double beam spectrophotometer; Hitachi, Ltd.). A disposable disposable cuvette (semi-micro, optical path length 10 mm, optical path width 4 mm) was used for the cell, and ultrapure water was used for the reference. The result is shown in FIG.

As shown in FIG. 10, the transmittance of the comparative control (BC dispersion before drying) was 79.5%, whereas the transmittance of the restored BC dispersion (sample p) was 64.0%. It was an equivalent value. That is, the dispersion in which the dried product of BC bound with HPC-3 was dispersed showed the same high dispersibility as before drying. From this result, it is clarified that, by replacing the dispersion medium of the BC dispersion liquid with water and then drying, a BC dry product having high dispersibility in the liquid can be produced for BC combined with HPC. It was.

Claims

An organic solvent addition step A for adding an organic solvent to a bacterial cellulose dispersion obtained by dispersing bacterial cellulose in water;
A method for producing a dried dispersible bacterial cellulose product, comprising: a drying step B in which water and organic solvent are removed from the bacterial cellulose dispersion to which the organic solvent is added to dry the bacterial cellulose.
The dispersion according to claim 1, further comprising a heating and stirring step A ′ in which the bacterial cellulose dispersion added with a dispersant is stirred while being heated to a temperature higher than 45 ° C. before the organic solvent adding step A. For producing dried bacterial cellulose.
The method for producing a dried product of dispersible bacterial cellulose according to claim 2, wherein the warming stirring step A 'is a step of stirring at a temperature exceeding 45 ° C for a time exceeding 15 minutes.
The bacterial cellulose dispersion to which the dispersant used in the warming and stirring step A ′ is added is a bacterial cellulose dispersion to which the dispersant is added so as to have a concentration of more than 9 (w / w)%. Item 4. The method for producing a dispersible bacterial cellulose dried product according to Item 2 or Item 3.
The method for producing a dried product of dispersible bacterial cellulose according to any one of claims 2 to 4, wherein the dispersant is one or more selected from the group consisting of carboxymethylcellulose, hydroxypropylcellulose, and hydroxyethylcellulose.
A reconstituted water dispersion step X for preparing a reconstituted bacterial cellulose dispersion by dispersing a dried bacterial cellulose obtained by removing water and organic solvent and drying, in water containing a dispersant,
A method for producing a bacterial cellulose dispersion, comprising: a heating and stirring step Y for restoring, wherein the restored bacterial cellulose dispersion is stirred while being heated to a temperature of more than 45 ° C.
The method for producing a bacterial cellulose dispersion according to claim 6, wherein the regenerating warming stirring step Y is a step of stirring at a temperature exceeding 45 ° C for a time exceeding 15 minutes.
The method for producing a bacterial cellulose dispersion according to claim 6 or 7, wherein the dispersant is one or more selected from the group consisting of carboxymethylcellulose, hydroxypropylcellulose and hydroxyethylcellulose.
A method for producing a bacterial cellulose dispersion, comprising an organic solvent dispersion step Z in which bacterial cellulose formed by binding hydroxypropylcellulose is dispersed in an organic solvent.
Dispersion medium replacement step C for replacing the dispersion medium of the bacterial cellulose dispersion formed by dispersing bacterial cellulose in water with water from an organic solvent,
A drying step D for removing the dispersion medium from the bacterial cellulose dispersion with the dispersion medium substituted and drying the bacterial cellulose;
A method for producing a dry product of dispersible bacterial cellulose, wherein the bacterial cellulose is bacterial cellulose formed by binding hydroxypropylcellulose.