JPH08127601A - Freeness regulating agent - Google Patents

Abstract

PURPOSE: To obtain a freeness regulating agent, comprising a substance prepared by carrying out the spinner culture of a specific microorganism capable of producing cellulose and having excellent freeness regulating actions. CONSTITUTION: This regulating agent comprises a defiberized cellulosic substance prepared by carrying out the spinner culture of a microorganism capable of producing cellulose, preferably a microorganism of the genus Acetobacter [e.g. Acetobacter xylinum subsp. sucrofermentans (FERM P-1346, FERM BP-4545)]. Furthermore, the regulating agent is preferably obtained by carrying out the defiberizing treatment in a suspension containing <=0.1wt.% cellulosic substance. The culturing is preferably conducted under conditions of, e.g. about pH 5, 25-35 deg.C temperature and 21-80wt.% oxygen concentration fed to a culture apparatus.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a freeness adjusting agent, especially
A cellulosic substance that can be produced by stirring and culturing a cellulosic bacterium (hereinafter referred to as "bacterial cellulose").
Or called "BC". ) It relates to a freeness adjusting agent comprising a disaggregated material.

[0002]

2. Description of the Related Art BC (bacterial cellulose) is edible and used in the food field and has excellent water-based dispersibility. Therefore, the viscosity of foods, cosmetics, paints, etc. is maintained, the dough for food materials is strengthened, and the water content is retained. It has industrial value as a food stability improvement, low calorie additive or emulsion stabilization aid. BC is characterized in that the width of fibril fragments is as small as about double digits as compared with cellulose produced from wood pulp or the like. Therefore, the disaggregated material of BC has various industrial applications as a reinforcing agent for polymers, particularly aqueous polymers, based on such structural and physical characteristics of microfibrils. A substance obtained by solidifying such a cellulosic dissociated material into a paper-like or solid form exhibits a high tensile elastic modulus, and therefore, excellent mechanical properties based on the structural characteristics of microfibrils are expected, and application as various industrial materials is expected. is there. For example, as an example of using bacterial cellulose for the purpose of improving the yield of the filler without lowering the paper strength, JP-A-1-246495 discloses that it can be obtained by static culture of a microorganism belonging to the genus Acetobacter. A method of adding the bacterial cellulose disaggregated product and the cationic polyelectrolyte to a papermaking raw material suspension is disclosed. In addition, JP-A-5-247879
Japanese Patent Publication discloses a papermaking book and an acoustic diaphragm using bacterial cellulose obtained by static culture.

[0003]

DISCLOSURE OF THE INVENTION The present inventors have conducted extensive studies on new industrial uses of bacterial cellulose and found that the disaggregated product of bacterial cellulose obtained by the stirring culture method is excellent as a freeness adjusting agent. The present invention has been completed by finding out that it has the above function.

[0004]

That is, the present invention relates to a freeness adjusting agent comprising a cellulosic material disaggregated product which can be produced by stirring and culturing a cellulosic bacterium.

The cellulose-producing bacterium used in the present invention is, for example, Acetobacter xylinum subsp. Sucroferm .
entans ), Acetobacter xylinum ( Acetobacter
xylinum ) ATCC23768, Acetobacter xylinum ATCC23769, Acetobacter pasteurianus ATCC10245, Acetobacter xylinum ATCC14851, Acetobacter xylinum ATCC11142 and Acetobacter xylinum ATCC10821 and other acetic acid bacteria (genus Acetobacter). , Agrobacterium, Rhizobium, Sarsina, Pseudomonas, Achromobacter, Alcaligenes, Aerobactor, Azotobacter and Zugrea and NTG
These are various mutant strains created by mutation treatment by a known method using (nitrosoguanidine) or the like.
The BPR2001 strain was deposited on February 24, 1993, at the Patent Microorganism Depositary Center, Institute of Biotechnology, Institute of Technology, Ministry of International Trade and Industry (accession number FERM P-1346).
6) and subsequently transferred to a deposit under the Budapest Treaty on the International Recognition of Deposits for Patent Procedures (accession number FERM BP-4545) on February 7, 1994.

Examples of the chemical mutagenesis treatment method using a mutagen such as NTG include Bio Factors, Vol. 1, p. 297-302.
(1988) and J. Gen. Microbiol, Vol. 135, p. 2917-2.
Some are described in 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 such as irradiation. In the composition of the medium used for stirring culture of the present invention, sucrose, glucose, fructose, mannitol, sorbitol, galactose as a carbon source,
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 Bac
t-Peptone, Bact-Soytone, Ye
Nitrogen-containing natural nutrient sources such as ast-Extract and soybean concentrate may be used. Amino acids, vitamins, fatty acids, nucleic acids, 2,7,9-tricarboxy-as organic micronutrients
1H pyrrolo [2,3,5] -quinoline-4,5-dione, sulfite waste liquor, ligninsulfonic acid and the like may be added.

[0007] When using an auxotrophic mutant strain 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 acids or salts thereof (Japanese Patent Application No. 5-19914).
67), invertase (Japanese Patent Application No. 5-331491)
No.), methionine (Japanese Patent Application No. 5-335564), and the like may be appropriately added to the medium. For example, when acetic acid bacteria are used as the production bacteria, the pH of the culture is controlled to 3 to 7, preferably around 5. The culture temperature is 10 to 40 ° C, preferably 25 to 3
Perform in the range of 5 ° C. The oxygen concentration supplied to the culture device is 1 to
It may be 100%, preferably 21 to 80%. Those skilled in the art can appropriately select the composition ratio of each component in these media and the inoculation of bacterial cells into the media according to the culture method.

The stirring culture referred to in the present invention is a culturing method which is carried out while stirring the culture solution. By adopting the stirring culture method, the freeness is adjusted as compared with the bacterial cellulose produced by the stationary culture method. The function as an agent has improved dramatically. That is, by the stirring action received during culture, the structure of bacterial cellulose is changed, for example, so that the crystallization index decreases and the amorphous part increases, the affinity with pulp and the like increases, and the excellent drainage is obtained. It is possible to obtain the effect of decreasing the degree. As the stirring means, for example, an impeller, an air lift fermenter, a pump-driven circulation of fermentation broth, a combination of these means, or 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, there is provided a method for producing a cellulosic substance in which a culture solution containing cells is circulated between a culture device and a separation device described in Japanese Patent Application No. 6-192287 in the name of the present applicant, wherein the separation device is used. And a method for culturing a cellulose-producing bacterium described in Japanese Patent Application No. 6-192288 in the name of the present applicant, which is characterized in that a cellulosic substance which is a product is separated from the cells and the culture solution. A method for producing a cellulosic material by continuously extracting the culture solution from the culture system during the culture period and supplying a new culture solution of approximately the same volume as the withdrawal amount during the culture. There is the above-mentioned production method, characterized in that the concentration of the cellulosic substance in the culture solution is maintained 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,
Aeration may be performed if necessary. The term “aeration” as used herein may be any of a gas containing oxygen such as air and a gas not containing oxygen such as argon and nitrogen, and these gases may be selected according to the conditions of the culture system. Will be selected accordingly. 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 stirred at the same time as supplying oxygen required for the growth of the microorganisms by aerating a gas containing oxygen.

The disaggregation phenomenon of bacterial cellulose is considered to be a phenomenon in which the stress generated inside the cellulose by a mechanical external force or the like deforms or destroys it. Therefore, the disaggregation treatment of bacterial cellulose can be performed by applying a mechanical external force to the bacterial cellulose. The mechanical external force mentioned here includes, for example, stress such as tension, bending, compression, twisting, impact and shearing, but generally, compression, impact and shearing stress are the main components. 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 with a mixer, the mechanical external force is mainly composed of an impact force caused by the collision of the stirring blade and the bacterial cellulose and a shear force generated by the displacement phenomenon due to the speed difference of the medium. In the disaggregation process with Polytron, mechanical external force is the compressive force due to the bacterial cellulose being sandwiched between the external and internal teeth, the impact force due to the collision between the rapidly rotating tooth and the bacterial cellulose, the stationary external tooth and the high speed. Shear stress generated in the medium existing in the gap between the rotating inner teeth is the main component. In disaggregation by an ultrasonic pulverizer, the mechanical external force is mainly cavitation (cavity phenomenon) continuously generated in the medium due to the oscillation of the ultrasonic oscillating portion, and mainly the remarkable shear stress locally generated.

The disaggregation treatment of the present invention can be carried out by any method other than the above specific examples as long as a constant load (mechanical external force) can be applied to bacterial cellulose. Bacterial cellulose in suspension is about 0.1
When the disintegration treatment is carried out in the range of not more than wt%, a disintegrant having a great effect as the freeness adjusting agent of the present invention can be obtained. Also,
These disaggregation treatments include water, an electrolyte such as calcium chloride and sodium chloride in a solvent, a pigment, an inorganic compound such as activated carbon fine particles, a sizing agent, a yield improving agent, a fluorescent agent, an antifungal agent,
An antistatic agent and an organic compound such as latex may be mixed in advance.

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

The freeness adjusting agent of the present invention can be produced, for example, by the following method. Bacterial cellulose obtained by stirring culture is separated from the culture solution by a centrifugation method, a filtration method, or the like. The bacterial cells produced by the method of the present invention may be recovered as 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. In order to remove impurities, washing with water, pressure dehydration, dilute acid washing, alkali washing, treatment with a bleaching agent such as sodium hypochlorite and hydrogen peroxide, treatment with a lytic enzyme such as lysozyme,
Impurities can be almost completely removed from the cellulosic substance by performing treatment with a surfactant such as sodium lauryl sulfate and deoxycholic acid, and washing with heating 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 heteropolysaccharides, constituents other than cellulose include mannose, fructose, galactose, xylose,
Hexoses such as arabinose, rhamnose, glucuronic acid,
Examples include pentose sugar and organic acids. Note that these polysaccharides may be a single substance, or two or more types of polysaccharides may be mixed due to hydrogen bonds or the like.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the Examples are not intended to limit the present invention.

[0015]

【Example】

Examples and Comparative Examples (1) Preparation of Seed Bacteria Solution (Proliferation of Bacterial Cells) Cellulose-producing bacteria were grown in a flask culture method. Fructose 40 g / L, phosphate-potassium 1.0 g / L, magnesium sulfate 0.3 g / L, ammonium sulfate 3 g / L, bacto-peptone 5 g / L, lactic acid 1.4 ml / L, initial composition of pH 5.0 Medium 100
BPR in a 750 ml Roux flask filled with ml.
1 ml of a cryopreserved bacterial solution of 2001 strain (FERM BP-4545) was inoculated, and static culture was carried out at 28 ° C. for 3 days in a constant temperature incubator. After the seed culture, the Roux flask was shaken well, and the contents were gauze-filtered under aseptic conditions to obtain a seed bacterial solution.

(2) Production of Bacterial Cellulose by Stirring Culture 60 ml of the above seed bacterial solution was aseptically inoculated into a small jar fermenter (total volume 1000 ml) in which 540 ml of a sterilized medium for stirring culture described later was put. 72 at 30 ° C
While controlling the pH to 5.0 with 1N NaOH or 1N H ₂ SO ₄ , the stirring rotation speed was initially 400 rpm, and the dissolved oxygen content (DO) was 3.0 to 21.
Stirring culture was performed with a jar fermenter while automatically controlling the number of revolutions so as to be within 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 soybean concentrate (soybean Acid hydrolysis concentrate of protein) 5 g / L Initial pH 5.0 After culturing, solids in the jar fermenter are collected and washed with water to remove medium components, and then 110 ° C. in 1% NaOH aqueous solution, The cells were treated for 20 minutes to remove the cells. Further, the produced cellulose was washed with water until the washing liquid became nearly neutral to obtain bacterial cellulose.

(3) Production of Bacterial Cellulose (Comparative Example) by Stationary Culture 600 ml of the medium having the composition described in (2) was aliquoted in sterile Petri dishes in an amount of 30 ml each, and allowed to stand at 30 ° C. for 7 days. Static culture was performed. After completion of the culture, the bacterial cellulose formed on the surface of the dish was washed with water to remove the medium components.

(4) Disaggregation treatment of bacterial cellulose Water was added to the washed bacterial cellulose obtained by the stirring culture method of (2) to adjust the disaggregation concentration (dry weight of bacterial cellulose / volume). Next, this suspension was disaggregated at a temperature of 25 ° C. for a predetermined time by using a stirrer (blender manufactured by Oster). The rotation speed of the stirrer was set to the highest level. By the above disaggregation treatment, bacterial cellulose disaggregate (A)
(E), that is, the freeness adjusting agent of the present invention was obtained.

[0019]

[Table 1] Disaggregation treatment conditions Bacterial cellulose disaggregate Disaggregation concentration Concentration Treatment time (A) 0.4% 3 minutes (B) 0.1% 3 minutes (C) 0.1% 45 seconds (D) 0.05% 45 seconds (E) 0.02% 45 seconds

Similarly, water was added to the washed bacterial cellulose obtained by the stationary culture of (3) to adjust the disaggregation concentration to 0.4% (dry weight of bacterial cellulose / volume). Next, this suspension was disaggregated with a stirrer (blender manufactured by Oster) at 25 ° C. for 3 minutes. The rotation speed of the stirrer was set to the highest level. A comparative bacterial cellulose disaggregated product (F) was obtained by the disaggregation treatment.

(5) Freeness Test (CSF) A bacterial cellulose disaggregated product prepared by the above-mentioned method and J
Hardwood bleached kraft pulp (LBKP) disaggregated according to IS-P-8209 was mixed, and JIS-P-81 was used.
According to No. 21, the Canadian standard freeness (CSF) was measured.

[0022]

[Table 2] Evaluation results BC disaggregated product BC disaggregated product: LBKP mixing ratio CSF (cc) (dry weight ratio) A 2.5: 97.5 420 A 5: 95 270 A 10: 90 130 B 5: 95 180 C 5: 95 220 D 5: 95 230 E 5: 95 225 ───────────────────────────────── F ( Comparative Example) 2.5: 97.5 490 5: 95 410 10: 90 300

From the above results, it can be seen that the bacterial cellulose disaggregated product of the present invention has an excellent freeness adjusting effect.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication C12S 3/08 8931-4B (C12P 19/04 C12R 1:02) (72) Inventor Yasushi Morinaga Kanagawa Biopolymer Research Co., Ltd. 3-2-1 Sakado, Takatsu-ku, Kawasaki, Japan (72) Inventor Fumihiro Yoshinaga 3-2-1 Sakado, Takatsu-ku, Kawasaki-shi, Kanagawa Biopolymer Research Co., Ltd.

Claims (3)

[Claims] 1. A freeness adjusting agent comprising a cellulosic substance disaggregated product, which can be produced by stirring and culturing a cellulose-producing bacterium. 2. The freeness adjusting agent according to claim 1, wherein the cellulose-producing bacterium belongs to the genus Acetobacter. 3. The freeness adjusting agent according to claim 1, wherein the disintegration treatment is carried out in a suspension containing a cellulosic substance in an amount of 0.1% by weight or less.