KR101300625B1 - Fabrication method of bacterial cellulose gel - Google Patents

Abstract

PURPOSE: A cellulose gel which is prepared by a method is provided to obtain a cellulose product with same product quality. CONSTITUTION: A method for manufacturing a microbial cellulose gel comprises the steps of: adding microbial strains to a medium and culturing the strains to prepare a first cellulose gel; pulverizing a mixture of the first cellulose and water and obtaining pulverized cellulose; and mixing the pulverized cellulose and water and adding an excipient; and stirring at 60°C or higher to prepare a second cellulose gel. The excipient includes galactomannan, glucomannan, guar gum, locust bean gum, pluronic, agar, algin, carrageenan, xanthan gum, tara gum, tamarind gum, and gellan.

Description

Fabrication method of bacterial cellulose gel

The present invention relates to a method for producing a microbial cellulose gel, and more particularly, to a method of preparing a cellulose gel having excellent productivity and quality by pulverizing a cellulose gel produced first through microbial culture to obtain finely divided cellulose and again gelling it. Suggest.

Cellulose, the basic structural component of plant cell walls, accounts for 33% of all plant material and is the most abundant organic compound produced. Cellulose is an economically important material because it is processed to produce paper and fibers and can be chemically transformed into materials that make products such as plastics, photographic films, and rayon. Other cellulose derivatives are used in adhesives, explosives, food thickeners and moisture proof coatings.

Cellulose is one of the most abundant biomaterials in nature. Especially since it has been reported that acetic acid bacteria produce cellulose, bacterial cellulose produced by microorganisms has been the subject of constant research as a new material. Has attracted much attention not only as an additive in food but also as a new value-added industrial material.

 Plant-derived cellulose and bacterial cellulose make a big structural difference. Bacterial cellulose derived from microorganisms is a ribbon in which long chains of beta-D-glucopyranose and beta-1,4-glucoside (β-1,4-glucoside) are bonded by hydrogen bonds. In the form of rib-like bundles, there are structural differences from plant-derived cellulose in the form of microfibrils bundles.

In addition, unlike cellulosic cellulose, bacterial cellulose does not contain any components other than cellulose, so it is easy to separate and purify. In other words, plants have a crystalline structure that contains not only cellulose but also hemicellulose or lignin, but bacterial cellulose does not contain any impurities other than cellulose produced by bacteria. And purification is easy.

Microbial-derived bacterial cellulose is the only natural cellulose that can be obtained as a film. The gel-like microbial cellulose sheet has not only very similar properties to pulp, but also has higher density and three-dimensional network structure than pulp. In this way, products can be developed that take advantage of these properties. For example, the microbial cellulose film produced by culturing the strains of the genus Acetobacter after treatment as a gel in its original form and compacted to reduce moisture content is a wet mask, a cosmetic mask pack as a wet sheet. It can be used as a medical burn treatment. In particular, the microbial cellulose in the gel state is easy to contain an additive therein, and is effective for expressing various functionalities.

Conventional film-type microbial cellulose sheet was manufactured by the following method. First, as shown in FIG. 1, a medium is prepared and inoculated with appropriate bacteria, followed by culturing for a predetermined period in a culture chamber in which temperature and humidity are controlled to obtain a cellulose bulk sheet formed in a gel state in an upper portion of the culture medium.

The bulk microbial cellulose sheet thus prepared has problems such as damage that the surface does not grow cleanly and uniformly in the culture process (see FIG. 2). In this case, since the undesired poor microbial cellulose sheets must be discarded, the amount of cellulose sheets that can be used as the actual product is small, and the yield of the product is inevitably lowered.

In addition, the bulk microbial cellulose sheet must be processed to a suitable thickness, for example, to be used as a mask pack, but the process difficulty that it is very difficult to uniformly slice a cellulose sheet having a low physical strength to a thin thickness. exist. In particular, microbial cellulose grown in uneven thickness has a small amount of sheets that can be used as a real product during the slicing process, thereby accelerating the yield reduction problem.

After all, despite the various functions and utilization value of microbial cellulose, there is a limit in improving the yield of the actual product due to the quality problems of the prepared bulk microbial cellulose and the difficulty of the slicing process, and thus the industry using microbial cellulose The development of microbial cellulose production and processing technology is more urgently needed to develop.

The present invention has been made under the above technical background, and an object of the present invention is to provide a new method for preparing microbial cellulose gel.

In addition, another object of the present invention is to provide a method for producing a secondary microbial cellulose gel that does not degrade the function and effect by utilizing the primary microbial cellulose gel surface damage occurs in the culture process.

In addition, another object of the present invention is to improve the production yield of microbial cellulose gel to promote the expansion and development of industries utilizing microbial cellulose.

Other objects and technical features of the present invention will be more specifically described in the following detailed description.

In order to achieve the above object, the present invention is prepared by injecting a microorganism strain into the culture medium to produce a first gelled first cellulose gel, and by grinding the first cellulose gel to obtain finely divided cellulose, Secondary gelling of micronized cellulose It provides a method for producing microbial cellulose gel, characterized in that the second cellulose gel is prepared.

Preferably, the second cellulose gel is prepared at a temperature of 60 ° C. or higher, and the cellulose obtained by pulverizing the first cellulose gel can be gelated by, for example, adding an excipient. The gelation process of the micronized cellulose may further include a large amount of water, and may further include other functional additives to change the functionality of the cellulose gel.

The second cellulose gel may be compressed to improve density and reduce moisture content. The compressed second cellulose gel may be sliced to a thin thickness and processed into a product for a mask pack or a medical treatment through a molding process.

The second cellulose gel has a lower fiber density than the first cellulose gel while maintaining the same water content, and the density may be maintained at the same or similar degree.

The present invention also provides a cellulose gel prepared by the above-described method, wherein the length of the fiber in the cellulose is finely divided to 0.1 to 10 mm, and the water content of the fiber is in the range of 1:99 to 30:70. It provides a micronized fibrous cellulose gel, characterized in that.

According to the present invention, the second cellulose gel finally obtained through the two gelling processes has a finer fiber length than the first gelled first cellulose gel, while the water content or density is similar to provide cellulose products of the same quality. It can manufacture.

In addition, it is possible to contribute to cost reduction by reducing the amount of raw materials used in the production of microbial cellulose gel-related products, and can significantly improve the competitiveness of microbial cellulose-related products by significantly increasing the production yield of cellulose gel.

In addition, it is excellent in moldability of the cellulose gel to facilitate the processing of cellulose applications, and may be applied to various fields including a functional additive or a dye.

1 is a manufacturing process diagram of a conventional microbial cellulose gel
Figure 2 is a photograph showing the surface damage of the prepared bulk cellulose gel
Figure 3 is a manufacturing process of the microbial cellulose gel according to the present invention
Figure 4 is a photograph showing a first cellulose gel
5a and 5b are photographs showing micronized cellulose
6A and 6B are surface and cross-sectional microstructure photographs of the first cellulose gel
7a to 7c is a microstructure photograph of the second cellulose gel according to the grinding time
8 is a photograph showing a mask pack made of a second cellulose gel
Figure 9 is a photograph showing a mask pack made of a first cellulose gel
10 is a photograph showing another mask pack made of a second cellulose gel

The present invention relates to a novel microbial cellulose gel manufacturing process, and proposes a method for producing a cellulose gel in which raw materials are reduced and mass production is easy while maintaining physical properties and quality through a second gelation process.

Specifically, the present invention increases the production yield of cellulose gel by pulverizing the primary cellulose gel obtained through the stationary culture and then gelling in the preparation of microbial cellulose having high crystallinity and excellent physical properties such as mechanical strength, adsorption, and water retention. In addition, processability and product functionality are improved.

Process for producing a microbial cellulose gel according to the present invention is as shown in FIG.

First, a cellulose culture process by microbial fermentation is performed (step S110). A culture medium is prepared by filling a prepared medium and a microbial strain. Specifically, a medium for producing bacterial cellulose to which at least one of sucrose, glucose and fructose is added as a carbon source is prepared. Incubate under conditions.

Strains producing microbial cellulose include Acetobacter sp., Agrobacterium sp., Rhizobium sp., Pseudomonas sp., And Sarcina sp. ), And among the Acetobacter sp., Acetobacter xylium, acetobacter pasteurinus and acetobacter hanseni are known. The present invention does not particularly limit the strain used to produce microbial cellulose, and various strains may be used depending on the type of culture solution.

In addition, as an auxiliary carbon source for the production of microbial cellulose can be used among natural materials such as citrus and persimmon vinegar, apple juice, grape juice, citrus juice, beer waste liquid, coconut by-products, etc. Do not limit.

Obtain bacterial cellulose from the culture. As suitable culture conditions, the culture temperature is maintained at a temperature in the range of 10 to 40 ° C., preferably 25 to 35 ° C., and the incubation period is maintained at 5 to 20 days. In order to create aerobic conditions in the culture, the oxygen concentration in the culture chamber may be maintained in the range of 1 to 100% (w / w), preferably 20 to 80% (w / w).

Through this culture, a first cellulose gel is obtained (step S120), and the produced first cellulose gel maintains a constant density and moisture content as a bulk in the form of a thick film as shown in FIG. 4. Depending on the culture period, the first cellulose may have a thickness of about 5 mm to 20 mm.

The obtained first cellulose gel obtains finely divided cellulose through a grinding process (step S130). Grinding | pulverization can grind | pulverize bulk type cellulose gel in the range of 0.1-10 mm of fiber length, for example through an industrial mixer. A large amount of water may be added in the process of micronization through grinding, and water may be subsequently added after grinding. The finely divided cellulose after grinding may have an increased water content and a lower density when compared to the first cellulose gel.

The appearance of micronized cellulose is shown in FIGS. 5A and 5B. As the first cellulose gel used for grinding, not only the cellulose gel normally grown through the culture process but also the poorly grown cellulose gel shown in FIG. 2A may be used. The grinding method for micronization of the first cellulose gel is not particularly limited, and may be a method such as physical crushing, pressing, stirring, or chemical treatment by mixing reaction with the additive.

Micronized cellulose is secondary gelled A second cellulose gel is prepared (step S140). The second cellulose gel can be gelated by adding an excipient, for example, to the cellulose which is pulverized and pulverized the first cellulose gel. Excipients include, for example, galactomannan, glucomannan, guar gum, locust bean gum, pluronic, agar, algin, carrageenan, xanthan gum, tara gum, tamarind gum, gellan, etc. Gelling agents may be used, and there is no particular limitation on the type of excipient.

The gelation process of the micronized cellulose may further include a large amount of water, and may further include other functional additives to change the functionality of the cellulose gel.

The second cellulose gel is preferably prepared at a temperature of 60 ° C. or higher for facilitating gelation and for uniform mixing and reaction of the finely divided cellulose with the substances added for gelation.

The obtained second cellulose gel has a lower fiber density than the first cellulose gel, the moisture content is kept the same, and the density is maintained at the same or similar degree. In addition, while the length of the fiber in the second cellulose gel is reduced through the micronization process, the water content in the second gelling process is maintained in the range of 1:99 to 30:70 compared to the fiber.

The manufactured second cellulose gel may be imparted with functionality and moldability to be utilized in various products through a post process (step S150). For example, the second cellulose gel may be compressed to improve density and reduce moisture content. In addition, the compressed second cellulose gel may be sliced to a thin thickness or processed into a product for a mask pack or a medical treatment through a molding process. Through the pressing process, the physical strength such as the tensile strength of the second cellulose gel may be increased, and the moisture content in the second cellulose gel may be controlled through the water discharge. For example, in the case of the first cellulose gel, the water content is 98%, the fiber ratio is about 2%, the second cellulose gel may be adjusted to 50 to 60% of the moisture content through compression.

Functional additives such as emulsifiers (Beeswax, Tween # 60, etc.), preservatives (MP, PP, Saliethanol, etc.), moisturizers (Glycerin, etc.) are subjected to sterilization during the post-processing or gelling with the second cellulose gel for such processing. It may further include.

In the case of general microbial cellulose obtained through cultivation, processing of slices, etc. is difficult, and the yield of raw materials is low due to low normal product yield, while there is a limit in mass production, but the microbial cellulose gel of the present invention obtained through pulverization and secondary gelation is added. By greatly reducing the amount of raw materials, the formability for cost reduction and commercialization is significantly improved.

Hereinafter, the features of the present invention through the preferred embodiment in more detail.

Example 1 Micronized Cellulose Gel

As a strain for producing bacterial cellulose, the strain KCG326 of the genus Gluconacetobacter was used. For the preservation and preculture of the strain, glucose 10% (w / w), yeast extract 1% (w / w), CaCO ₃ 2% (w / w), agar 1.5% (w / w), remaining purified water, The basal medium was prepared by mixing pH 6.8.

As a pre-culture process, one platinum inoculated in a plate agar medium was inoculated into a SPL Incu Tissue container for plant tissue culture containing 200 ml of 272 medium, and cultured at 27 ° C. for 48 hours. Thereafter, 1% (w / w) of the pre-culture was inoculated on a tray containing the 1,300 mL of the culture, and then cultured at 30 ° C. for 14 days.

The resulting bulk bacterial cellulose in gel was isolated from the culture. As shown in FIG. 4, the separated cellulose gel (the first cellulose gel) was a thick film in which both normal growth and abnormal growth (uniform growth) existed.

The separated first cellulose gel was placed in a blender and repeatedly pulverized for 5 to 10 minutes to obtain micronized cellulose. The micronized cellulose obtained took the form of a mixed solution dispersed in water out of the gel state.

75 wt% of distilled water (DI water) was added to the finely divided cellulose, and 1 wt% and 0.5 wt% of carrageenan and xanthan gum were added as excipients, respectively, and the mixture was stirred uniformly while maintaining a temperature of 75 ° C. After the passage of time, the finely divided cellulose gelled with increasing density to obtain a second cellulose gel. It was confirmed that the obtained second cellulose gel was similar in size to the first cellulose gel while reducing the fiber content.

6A and 6B are microstructure photographs of the first cellulose gel, and the surface of the first cellulose gel prepared by incubating at 30 ° C. for 14 days was lyophilized to observe the surface of the first cellulose gel. It can be seen that the first cellulose gel before pulverization constitutes a three-dimensional structure as shown in the figure, and the upper surface of the cellulose gel is in the form of a porous sheet in which nanofibers are in the form of a mesh, and the cross section is a porous nanosheet in the layer. It can be seen that forming a three-dimensional solid structure connected to each other by fibers.

The microstructure of the second cellulose gel that was milled at different times is shown in FIGS. 7A to 7C. The grinding time was 5 minutes for the sample of FIG. 7A, 10 minutes for the sample of 7B, and 15 minutes for the sample of 7C. Using an electron microscope (SEM, JSM-6400, JEOL, Japan) was confirmed at 10kV, 10 ~ 12 mm distance conditions, each sample was measured by gold coating for 70 seconds using a sputter coater (Sputter coater). After freeze-drying the cellulose gel after pulverization, it was confirmed that the nanofibers were broken, and the nanofiber length was shorter as the pulverization time was increased. And the moisture content was similar as shown in Table 1 below.

Moisture Content Comparison First cellulose gel Gelled second cellulose gel after grinding 98.2% 98%

Example 2-Microbial Cellulose Gel Mask Pack

In order to prepare a mask pack with a microbial cellulose gel, the citrus juice was microbially fermented and the primary microbial cellulose gel was pulverized with a mixer, a grinder, a homomixer, etc. to obtain micronized cellulose. The pulverized citrus fermentation micronized cellulose was weighed to 30 wt% in the total crude solution, placed in the main container, and distilled water was weighed (70 wt%) and mixed and dispersed with citrus fermentation cellulose in the main container. Dispersion was dispersed for 20 minutes or more at 3000 rpm using a homomixer. At the time of dispersion, the main vessel was heated with a hot plate such that the temperature of the crude liquid was 60 ° C or higher.

After the dispersion was completed, the crosslinking agent was quantitatively mixed with distilled water, and then introduced into a main container, and carrageenan, LBG (Locust Bean Gum), and xanthangum (natural polymer) were mixed with glycerin (Glycerin) at room temperature. When the temperature of the micronized cellulose mixed with distilled water was 60 ° C. or more, the natural polymer mixed with glycerin was added to the main container, and then mixed and dissolved for 10 minutes at 800 rpm in an azimixer. After the dissolution was completed, preservatives and emulsifiers, fragrances, solubilizers and the like were added and again mixed and dissolved for 10 minutes at 800 rpm in an azimixer. Finally, defoaming was performed to complete the secondary cellulose gel.

The finished gel was coated on a transparent release paper for the purpose of peeling effect and product protection. The coating conditions were maintained at a temperature in the range of -5 ℃ to room temperature, the humidity was carried out by maintaining a temperature of about 50%, the coating thickness was maintained at about 0.5 ~ 1.2mm.

The coated secondary cellulose gel can be formed in various forms, and may be compressed before or after gel coating. The second cellulose gel was pressed and molded into a face shape to prepare a cosmetic mask pack (see FIG. 8). For comparison, the first cellulose gel before being micronized was pressed and molded to prepare a mask pack of the same type (see FIG. 9). The obtained mask packs were almost identical in color, form, physical strength and the like.

In addition, as a result of testing the tensile strength of the mask pack formed of the first cellulose gel and the mask pack formed of the second cellulose gel gelled after grinding, there was no significant difference as shown in Table 2, the second cellulose gel mask pack It showed that the tensile strength sufficient for use as, and can further improve the tensile strength according to the compression level.

Tensile Strength Comparison Mask pack formed of the first cellulose gel Mask pack formed of the second cellulose gel 4.88N / ㎠ 0.863 Ncm2

Therefore, it can be seen that the microbial cellulose gel prepared according to the present invention is very effective for producing a large amount of high quality mask packs even with a small amount of raw material.

FIG. 10 illustrates a mask pack close to golden color by adding a functional material expressing color to a second cellulose gel prepared in the same method as another embodiment. As such, the microbial cellulose gel according to the present invention can be utilized in various cosmetic mask packs, and is effective for application to medical treatment by adding other additives.

Existing cosmetic mask packs are mainly prepared by impregnating a lotion in a nonwoven fabric mainly containing plant cellulose or by applying collagen to a nonwoven fabric. Non-woven fabrics in mask pack materials are the most commonly used materials and water-retaining properties because of the advantages of simple molding and thickness control. On the other hand, burn medicine for medicine can be prepared by impregnating a burn treatment agent in a medical gauze, a fibrous material, in this case, in order to fully incorporate the burn treatment, the gauze must be laminated in several layers.

On the other hand, the microbial cellulose gel according to the present invention does not need to use a separate nonwoven fabric to maintain its shape as in the conventional mask pack because it is excellent in water retention, excellent moldability and physical strength. Even when used, the impregnation of other materials is easy and there is no need to form a thick layer structure.

Bacterial cellulose derived from microorganisms has high crystallinity and excellent physical properties such as mechanical strength, adsorption, water retention, suspension stability, and binding properties, compared to cellulose produced by general plants, so it is used in various fields such as food additives, industrial materials, and medical materials. The microbial cellulose gel of the present invention significantly increases the production yield of the cellulose gel by pulverizing the primary cellulose gel obtained through the static culture followed by secondary gelation, thereby greatly improving the industrial utilization of the microbial cellulose gel. I will.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, Modified, modified, or improved.

Claims (7)

Injecting the microbial strain into the culture medium and then cultured to prepare a first gelled first cellulose gel,
Grinding in the state of mixing the first cellulose gel with water to obtain finely divided cellulose out of the gel state,
Out of gel Water is mixed with the finely divided cellulose, an excipient is added and stirred at a temperature of 60 ° C. or higher. Second gelation to prepare a second cellulose gel,
The excipient is a gelling agent selected from galactomannan, glucomannan, guar gum, locust bean gum, pluronic, agar, algin, carrageenan, xanthan gum, tara gum, tamarind gum, and gellan.
Method for producing microbial cellulose gel.

delete delete The method of claim 1,
Further comprising the step of compressing the second cellulose gel microbial cellulose gel manufacturing method.
5. The method of claim 4,
Microbial cellulose gel manufacturing method further comprising the step of slicing the second cellulose gel.
The method of claim 1, wherein the second cellulose gel has a lower fiber density than the first cellulose gel.
delete

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