JP3708591B2 - Method for producing cellulose derivative - Google Patents

Description

【００２１】
実施例２
実施例１に示した酵素処理法で処理したパルプを以下に示したアルセル法でＣＭＣとし、酵素未処理ＣＭＣとの特性比較を行った。
・アルセル法
パルプを１８％水酸化ナトリウム水溶液に浸漬し、１〜２時間経過後圧搾して過剰の水酸化ナトリウムを除き、パルプ重量に対して３倍のアルカリセルロースをつくる。アルカリセルロースを粉砕機に移し破砕撹拌しながら、パルプ（無水グルコース単位）に対して１．２〜２．０モルのモノクロル酢酸ナトリウム粉末を添加する。系の温度を１０℃以下に保ちながら数時間破砕撹拌を続け、モノクロル酢酸ナトリウムの浸透を十分に行う。その後、破砕物を反応機に移し、撹拌しながら７０〜８０℃で約２時間保ちＣＭＣを得る。７５〜８０％メタノール水溶液で洗浄濾過を数回繰り返した後乾燥して、精製ＣＭＣを得た。
【００２２】
【表２】

【００２３】
実施例３
市販漂白パルプ（商品名「ＡＲＡＵＣＯ」）をｐＨ８のリン酸緩衝液で１５％のスラリ−とした後、ＳＤＸ酵素を１００Ｕ／ｇ（対絶乾パルプ）となるように添加する。このパルプスラリ−を７０℃で５時間撹拌しながら酵素処理した後、パルプをブフナーロート上で濾過脱水する。得られた酵素処理パルプを以下に示したメチルエーテル化法でメチルセルロースとした。対照として酵素未処理パルプをメチルエーテル化し、その特性を酵素処理メチルセルロースと比較した。
【００２４】
・メチルエーテル化法
パルプを約５０％濃度のカセイソーダ溶液に浸漬した後、圧搾してセルロースとほぼ等量のカセイソーダ及び水を保有するアルカリセルロースとする。これに当量よりわずかに多い塩化メチルを加え、オートクレーブ中で９５〜１００℃で反応させる。反応終了後、ブフナーロート上で熱水洗浄してから乾燥し、精製メチルセルロースを得る。
【００２５】
【表３】

【００２６】
【発明の効果】
本発明のセルロース誘導体の製造法により、従来のものと比較して濾過性が改善され、ミクロゲルの生成が抑えられたセルロース誘導体を得ることが出来、増粘剤、安定剤、懸濁化剤などとして有効に利用出来る。
また、使用する酵素によっては粘度を下げずに上記の特性改善が行えるため、特に有用である。[0001]
[Industrial application fields]
The present invention relates to a method for producing a cellulose derivative. More specifically, the present invention relates to a method for producing a cellulose derivative using cellulose treated with an enzyme.
[0002]
[Prior art / problems to be solved by the invention]
One type of cellulose derivative is cellulose ether, but cellulose ethers such as methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), and carboxymethyl cellulose (CMC) are non-caloric. Odorless, tasteless water-soluble or water-suspended white polymer. For this reason, it is widely used in fields such as foods, medicines, cosmetics, paper, and fibers as thickeners, binders, stabilizers, suspending agents and the like.
[0003]
Recently, as new applications of these cellulose ethers have been developed, cellulose ethers having high performance according to the use have been demanded. For example, it is excellent in salt water resistance and corrosion resistance, and has a small amount of microgel. The term “microgel” as used herein refers to a cellulose ether that is not completely solubilized in a solvent and becomes a semi-dissolved gel due to insufficient cellulose etherification.
[0004]
Conventionally, cellulose ether is prepared by immersing lignocellulose such as wood pulp or linter pulp in a high concentration alkaline solution to obtain alkali cellulose, and then an appropriate etherifying agent (for example, methyl chloride, ethyl chloride, ethylene oxide, propylene oxide, monochloroacetic acid). Etc.) have been taken into account.
[0005]
Cellulose ethers produced by this method are strongly affected by the degree of substitution (etherification degree) and the distribution of substituents, so that satisfactory characteristics cannot always be obtained depending on the application. For example, low-substituted cellulose ethers have poor solubility in solvents due to their heterogeneous etherification. In addition, a semi-dissolved gel-like substance called a microgel is likely to be generated, which is not preferable for sensory (visual and tactile) characteristics, but also causes poor filterability of the solution.
[0006]
Meanwhile, methods for treating pulp with enzymes have also been studied. Cellulase, xylanase, etc. are used as the enzyme. For example, in 1986, Viikari et al., Proceedings of the Symposium on Biotechnology in the Pulp and Paper Industry, Reported at 3rd International Conference.
[0007]
JP-A-2-245001 describes a method for producing a hydrolysis product by allowing cellulase to act on CMC. However, in this method, since CMC, that is, an etherified pulp is treated with an enzyme, many microgels are formed at the time of etherification. Therefore, in order to remove the microgel, it is necessary to use a large amount of enzyme, which causes a problem that the yield of the target hydrolyzate is significantly reduced. On the other hand, if importance is attached to the yield of the hydrolyzate, it is necessary to reduce the amount of enzyme to be used, so that there is a problem in that the enzyme treatment on the microgel portion becomes insufficient and the microgel remains. In addition, the hydrolyzate obtained by this method has a markedly lower viscosity than the original CMC, which is inconvenient when used as a thickener or binder.
Therefore, the subject of this invention is suppressing the generation | occurrence | production of the microgel in the process of manufacturing a cellulose derivative from a pulp, and providing the cellulose derivative with improved filterability.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that enzymes, particularly Bacillus sp. By treating with an enzyme prepared from the culture medium of SD902, the filterability of cellulose derivatives, which has been difficult to improve with conventional cellulose derivative production methods, the generation of microgels as much as possible, or the intramolecular substitution distribution can be reduced. The present invention has been completed by finding out the homogenization and increasing the water solubility of the cellulose derivative.
[0009]
That is, the present invention provides the following.
1) A method for producing a cellulose derivative, wherein the pulp is subjected to an enzyme treatment before chemical modification.
2) The method for producing a cellulose derivative as described in 1) above, wherein at least one of the enzymes used is an enzyme that hydrolyzes a β-1,4 glycosidic bond.
3) The method for producing a cellulose derivative according to 1) above, wherein at least one of the enzymes used is hemicellulase.
4) The method for producing a cellulose derivative according to 1) above, wherein at least one of the enzymes used is xylanase.
5) At least one of the enzymes used is Bacillus sp. The method for producing a cellulose derivative according to 1) above, which is a xylanase obtainable from SD902.
[0010]
6) The method for producing a cellulose derivative according to 1) to 5) above, wherein the chemical modification is etherification.
7) The method for producing a cellulose derivative according to 1) to 5), wherein the chemical modification is methyl etherification, ethyl etherification, hydroxyethyl etherification, hydroxypropyl etherification, or carboxymethyl etherification.
The present invention will be described in detail below.
[0011]
The pulp used in the present invention is a softwood, hardwood or non-wood-derived pulp that has been digested or variously bleached. The term “non-wood pulp” as used herein refers to pulp produced from bast fiber plants such as camellia, sanjo, abaca and kenaf and hard fiber plants such as straw, sugar cane and bagasse. In addition, cellulose derivatives having a low degree of chemical modification such as the degree of etherification, regenerated cellulose, and the like can also be used as pulp in the present invention.
[0012]
The enzyme used in the present invention may be single or plural, but at least one of them is preferably an enzyme that hydrolyzes a β-1,4 glycosidic bond, for example, cellulase or hemi Cellulase. More preferred is xylanase, and even more preferred is Bacillus sp. It is an enzyme derived from SD902. Bacillus sp. SD902 has been deposited at the Biotechnology Institute of Industrial Science and Technology under the accession number FERM P-13356, then transferred to an international deposit and assigned the accession number FERM BP-4508. This strain can be cultured according to the method described in JP-A-6-261750 to prepare an enzyme (hereinafter abbreviated as SDX enzyme).
The enzyme used need not be a pure enzyme, and may be a culture supernatant obtained by sterilizing enzyme-producing bacteria by centrifugation or the like, or an enzyme composition extracted from cells.
[0013]
Enzyme activity can be expressed by measuring a reducing sugar produced under reaction conditions of pH 7,50 ° C. using xylan as a substrate by the 3,5-dinitrosalicylic acid method. 1 U is defined as the amount of enzyme that produces 1 μmol of xylose per minute.
The enzyme treatment conditions of the pulp used in the present invention are not particularly limited as long as the pH, temperature, and time are set within the range in which the enzyme used maintains activity, but can be performed, for example, under the following conditions: . The treatment temperature is 20 to 90 ° C, preferably 40 to 80 ° C, the treatment time is 15 minutes to 24 hours, preferably 30 minutes to 5 hours, and the treatment pH is 3 to 9, preferably 4 to 8.
The enzyme addition amount is 1-1000 U / g (absolute dry pulp), preferably 2-250 U / g (absolute dry pulp). Here, if the amount of enzyme added is less than 1 U / g, the treatment effect is poor, and if it exceeds 1000 U / g, a decrease in pulp yield is observed, which is not a preferable amount of enzyme added.
[0014]
The pulp concentration may be a concentration at which stirring and mixing can be sufficiently performed, but is preferably 20% by weight or less.
The chemical modification after the enzyme treatment in the present invention is preferably etherification, more preferably alkyl etherification, hydroxyalkyl etherification, or carboxyalkyl etherification, and even more preferably methyl etherification, ethyl etherification, hydroxy Ethyl etherification, hydroxypropylation, or carboxymethyl etherification.
[0015]
For the chemical modification of the pulp after the enzyme treatment, any known method used for the chemical modification of the pulp can be used. For example, when manufacturing CMC, MC, EC, HEC, HPC, etc. from pulp, it is manufactured by a method roughly divided into two methods, an aqueous method using an aqueous medium as a reaction solvent and a solvent method using an organic solvent body. Can do.
Taking CMC as an example, in the aqueous medium method, the pulp soaked in a sodium hydroxide solution is crushed and stirred while adding the sodium monochloroacetate powder, and the pulp soaked in sodium monochloroacetate aqueous solution is ground and stirred with sodium hydroxide. There is a monochloro method in which is added.
On the other hand, in the solvent method, a 6-fold method using a mixed solution of ethanol and benzene and a 30-fold method using a 2-propanol aqueous solution can be used.
Moreover, as a chemical modification method other than the chemical method, a modification method using an enzyme can be used.
[0016]
【Example】
EXAMPLES Next, although an Example based on experiment demonstrates this invention further in detail, this invention is not limited at all by these Examples. In addition, all% described in an Example is based on weight%.
[0017]
Example 1
A commercially available bleached pulp (trade name “ARAUCO”) is made into a 5% slurry with a pH 6 acetate buffer, and then SDX enzyme is added to 50 U / g (absolute dry pulp). The pulp slurry is treated with stirring at 60 ° C. for 3 hours, and then the pulp is filtered and dehydrated on a Buchner funnel. The obtained enzyme-treated pulp was converted into CMC in accordance with the carboxymethyl etherification (CM conversion) method shown below, and the characteristics were compared with those of enzyme-untreated CMC.
[0018]
CMC characteristics were measured by the following method.
-Pulp CM conversion method After adding 1.8 mol of caustic soda per glucose group to pulp made into slurry by stirring in 88% isopropanol 30 times the weight of pulp, add 0.8 mol of monochloroacetic acid. The reaction is carried out at 70-80 ° C. for 2.5 hours. After completion of the reaction, filtration on a Buchner funnel and washing and filtration with a 75-80% aqueous methanol solution were repeated several times, followed by drying to obtain purified CMC.
[0019]
-A 0.5% concentration CMC aqueous solution constant at a filtration rate of 20 ° C was passed through a 200 mesh screen and the amount filtered in 5 minutes was measured with a graduated cylinder.
-It measured with the single cylinder type rotational viscometer using the CMC aqueous solution of 2% density | concentration constant temperature at 20 degreeC.
A 0.5% concentration CMC aqueous solution with a constant microgel amount of 20 ° C. was passed through a 200 mesh mesh sieve, and the wet weight of the remaining gel was expressed as weight% with respect to CMC.
[0020]
[Table 1]

[0021]
Example 2
The pulp treated by the enzyme treatment method shown in Example 1 was converted to CMC by the Arcel method shown below, and the characteristics were compared with those of enzyme-untreated CMC.
・ Dip the Alcer pulp into an 18% aqueous sodium hydroxide solution and squeeze it after 1-2 hours to remove excess sodium hydroxide to make 3 times as much alkali cellulose as the pulp weight. While the alkali cellulose is transferred to a pulverizer and pulverized and stirred, 1.2 to 2.0 mol of sodium monochloroacetate powder is added to the pulp (anhydrous glucose unit). While maintaining the temperature of the system at 10 ° C. or lower, crushing and stirring are continued for several hours to sufficiently penetrate sodium monochloroacetate. Thereafter, the crushed material is transferred to a reactor and kept at 70-80 ° C. for about 2 hours with stirring to obtain CMC. Washing and filtration with a 75-80% aqueous methanol solution were repeated several times, followed by drying to obtain purified CMC.
[0022]
[Table 2]

[0023]
Example 3
After making commercially available bleached pulp (trade name “ARAUCO”) a 15% slurry with a phosphate buffer of pH 8, SDX enzyme is added to 100 U / g (against dry pulp). The pulp slurry is subjected to enzyme treatment with stirring at 70 ° C. for 5 hours, and then the pulp is filtered and dehydrated on a Buchner funnel. The obtained enzyme-treated pulp was converted to methyl cellulose by the methyl etherification method shown below. As a control, the enzyme-untreated pulp was methyletherified and its properties were compared with enzyme-treated methylcellulose.
[0024]
-After immersing the methyl etherified pulp in caustic soda solution having a concentration of about 50%, the pulp is squeezed into alkali cellulose containing caustic soda and water in an amount approximately equal to that of cellulose. To this is added a little more than the equivalent amount of methyl chloride and the reaction is carried out in an autoclave at 95-100 ° C. After completion of the reaction, the solution is washed with hot water on a Buchner funnel and dried to obtain purified methylcellulose.
[0025]
[Table 3]

[0026]
【The invention's effect】
According to the method for producing a cellulose derivative of the present invention, it is possible to obtain a cellulose derivative in which filterability is improved as compared with the conventional one and generation of microgel is suppressed, and a thickener, a stabilizer, a suspending agent, etc. Can be used effectively.
Further, depending on the enzyme used, the above properties can be improved without lowering the viscosity, which is particularly useful.

Claims (6)

A method for producing a cellulose derivative, which comprises carrying out an enzyme treatment before chemically modifying pulp , wherein at least one of the enzymes is an enzyme that hydrolyzes a β- 1,4 -glycoside bond . The method of claim 1, wherein at least one of the enzymes is hemicellulase. The method of claim 1, wherein at least one of the enzymes is a xylanase. 4. The method according to claim 1 or 3, wherein at least one of the enzymes is a xylanase obtainable from Bacillus sp. SD902. The chemical modification is etherification process according to any one of claims 1-4. The method according to any one of claims 1 to 5, wherein the chemical modification is methyl etherification, ethyl etherification, hydroxyethyl etherification, hydroxypropyl etherification, or carboxymethyl etherification.