JPH09105089A - Treatment of pulp by utilization of enzymatic reaction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating pulp by the utilization of an enzymatic reaction, capable of increasing contact degree with the cellulose component to improve the treatment efficiency by holding the pulp in a wet state after digestion, and subsequently treating the wet pulp with microorganisms and/or an enzyme. SOLUTION: This method for treating the pulp by the utilization of the enzymatic reaction with microorganisms and/or an enzyme for the treatment such as a bleaching treatment, a deinking treatment or a beating treatment, the improvement comprises adding the microorganisms such as white decay fungi or hemicellulase-producing fungi and/or an enzyme such as phenol oxidase or hemicellulase to semi-dried digested craft pulp and/or semi-dried digested sulfide pulp which have a water-holding degree of 150-1000%. Thus, the pulp is efficiently treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating pulp which is essential to treat pulp with an enzyme or a microorganism, and particularly for efficiently treating a pulp containing cellulose fiber as a main component with an enzyme or a microorganism. Regarding the method.

[0002]

2. Description of the Related Art In recent years, there has been remarkable progress in biotechnology, and its application has been vigorously studied in the fields of paper and pulp. As an attempt to modify the pulp by causing an enzyme to act on the pulp, for example,
A method for obtaining cellulose having excellent cholesterol-adsorbing property, oil-absorbing property, or protein-adsorbing property by reacting a pulp fiber with a cellulase-containing enzyme has been disclosed (JP-A-3-88801).

Further, a method for producing a sanitary thin paper excellent in flexibility, water absorption, bulkiness and strength by causing a cellulose-degrading enzyme to act on pulp fibers (JP-A-5-14).
No. 8794), and a method for obtaining a diaper having excellent absorption performance by using an enzyme-treated pulp (JP-A-6-90978).

Further, after treating pulp by contacting it with a specific amount of cellulolytic enzyme, it is treated with a coagulant composed of a water-soluble cationic polymer to improve the freeness of paper.
Method for obtaining pulp (Japanese Patent Laid-Open No. 6-116887)
Alternatively, a method for obtaining crystalline cellulose having a large crystallinity and a high degree of polymerization (DP) by enzymatically hydrolyzing a wet lap pulp cellulosic material under specific conditions is disclosed (Japanese Patent Laid-Open No. 5-505421). ).

Attempts have also been made to utilize enzymes in the paper / pulp manufacturing process. As for bleaching, the residual chlorine content of the bleached pulp is treated by enzymatic treatment at any stage of the bleaching process. (Japanese Patent Application Laid-Open No. 3-505758), and a method for efficiently delignifying a lignocellulosic material using a lignin-degrading enzyme and xylanase (Japanese Patent Laid-Open No. 3-40887) is disclosed. By bleaching the pulp produced by the alkaline digestion method, treating it with an enzyme, and then making a paper,
A method for obtaining a base paper excellent in dimensional stability, glossiness and curl is disclosed (Japanese Patent Laid-Open No. 5-222688).

Further, a method for treating mechanical pulp in which a fibrous substance is treated with an enzyme to achieve a reduction in refining energy (JP-A-3-174079), the pulp is treated with a hemicellulose-acting enzyme of a microorganism, and then, A pulp bleaching method in which treated pulp is extracted and treated with chlorine dioxide (JP-A-4-245988), and an enzyme treatment method in which lignin is removed from a chemical lignocellulosic pulp by using xylanase are also disclosed (special features. Kaihei 4-316689).

On the other hand, as a method other than bleaching, a mechanical pulp for papermaking is treated with an enzyme having a pectin-decomposing activity and then beaten to obtain a pulp excellent in whiteness and opacity and having good strength. (JP-A-2-118191) and a method for improving the deinking effect by adding cellulase to a waste paper, subjecting it to an enzyme treatment, and then performing a deinking treatment (JP-A-2-8068).
No. 3).

As described above, studies have been made from various directions to modify the pulp by causing the enzyme to act on the pulp and to more efficiently perform the enzymatic treatment of the pulp in each of the paper / pulp manufacturing processes. There is. Regarding reaction conditions, in addition to enzyme-side conditions such as temperature, pH, and amount of enzyme,
Pulp-side conditions such as pulp concentration or type of pulp used are being studied. Further, in the manufacturing process, it has been attempted to improve the reactivity of the cellulose fiber by mechanical treatment such as ball mill treatment and pretreatment such as chemical treatment such as alkali immersion. However, since the hydrophobicity of cellulose, which is the main component of pulp, is high, a method that can sufficiently solve the problem that a reaction with an enzyme or the like having strong intermolecular bonding force in the pulp and being hydrophilic is difficult to occur. Not yet known.

[0009]

Therefore, the present inventors have conducted various studies on the relationship between the state of cellulose in the pulp and the reactivity in the process of treating the pulp with microorganisms or enzymes, and as a result, water retention after digestion has been investigated. It was found that the treatment proceeds efficiently when pulp having a degree of 150% or more is treated with microorganisms or enzymes, and the present invention has been achieved. Therefore, an object of the present invention is to provide a simple and inexpensive method by which pulp fibers such as wood pulp containing cellulose as a main component can be efficiently treated with enzymes and microorganisms.

[0010]

SUMMARY OF THE INVENTION The above objects of the present invention are as follows.
A method for treating pulp, which comprises a step of treating pulp with microorganisms and / or enzymes, wherein the pulp used during the treatment is a non-dry pulp having a water retention of 150 to 1000% after cooking. Was achieved by the following method of treating pulp.

The pulp fiber used in the method of the present invention is not particularly limited as long as it is a pulp fiber containing cellulose as a main component, and specific examples thereof include wood pulp, rice straw pulp, kraft pulp, sulfite pulp and Examples include kenaf pulp. The pulp raw material may be treated by a conventionally used method. For example, in the case of wood pulp, it can be treated chemically or mechanically. Further, kraft pulp and sulfite pulp can be mechanically treated similarly to wood pulp.

The pulp used in the present invention is required to be a non-dried pulp which has a water retention of 150% to 1000% after cooking and has not been dried after cooking. When the water retention is 150% or less, the reactivity between the enzyme and the pulp becomes insufficient. Further, it is practically impossible to obtain pulp of 1000% or more. In addition, the water retention here means the amount of water contained in the wet pulp squeezed by the centrifugal separator, as a percentage with respect to the absolutely dry pulp.

The method for measuring the water retention is described in J. TAPPI N
O. According to the method defined in 26-78, the disintegrated pulp suspension is centrifuged at 3,000 G, and the weight A of the dehydrated pulp and the absolute dry weight B dried at 105 ° C. are weighed and obtained. , Then (A−B) / B × 100 can be obtained. As a general rule, the amount of sample is 0.15 g and the time for centrifugation is 1
Do as 5 minutes.

In the present invention, in the process of processing various pulp raw materials, chemicals are mixed in or the pH is greatly deviated,
It is necessary to sufficiently wash the chemically or mechanically processed pulp within the above range of water retention so that the enzyme or the like is not inactivated by this and the progress of the reaction is not hindered.

In the present invention, the microorganisms used in the production process of each pulp can be used. For example, in the case of the white-rot fungi used in the pulp bleaching process, the genus Kawaratake, the genus Macaw, the genus Alocasia, the genus Tamachorei, the shiitake, the yamabushitake, the oyster mushroom, the enokitake, the moss mushroom, and the SKB strains are listed. In the case of cellulase-producing bacteria and hemicellulase-producing bacteria, filamentous fungi such as Trichoderma and Aspergillus are mentioned.

The concrete treating method of the pulp in the present invention is a usual treating method used in the production process of each pulp. For example, there may be mentioned a method in which a microorganism having pulp bleaching activity, a culture thereof, or a treated product thereof is added to a pulp-containing medium and treated at a temperature and pH suitable for the microorganism used for a predetermined period.

Further, since the culture conditions of the above-mentioned microorganisms vary depending on the strain used, it cannot be said that it is limited, but it is sufficient to select the conditions under which the strain used grows well. For ordinary bacteria, it is preferable that the pH is about 3 to 8 at 20 to 40 ° C. In the case of a thermophilic bacterium, the temperature becomes higher, and even if the culture temperature is 60 ° C. or higher, it may be good, and in the case of a psychrophilic bacterium, the temperature becomes lower. Also, if the bacteria are alkalophilic, the pH will be more alkaline,
There may be a case where the pH becomes good.

The enzyme used in the present invention may be any enzyme used in the production process of each pulp. For example, in the case of phenol oxidase, examples include peroxidase and laccase, and in the case of hemicellulase and cellulase, cellulase amano (trade name of Amano Pharmaceutical Co., Ltd.), cell crust (trade name of Novo Co.), bagtosol. DCLQ (trade name of Sand Corp.), Pulpzy
me (trade name of NovoNordisk), Eco
Pulp (trade name of Alko Co.) and the like can be mentioned.

The concrete treatment method of the pulp may be a usual treatment method used in the production process of each pulp, for example, by immersing the pulp in a liquid in which the enzyme is dissolved to cause the reaction. Regarding the amount of the enzyme used during the treatment, the reaction conditions, etc., the enzyme activity and the optimum conditions vary greatly depending on the enzyme used, so it is necessary to set the conditions suitable for the properties of the enzyme used.

For general enzymes, the treatment temperature is 20 to
40 [deg.] C. and pH of about 3 to 8 are good. The temperature will be higher if the enzyme is a thermophilic enzyme, and it may be good even at 60 ° C or higher.
In addition, if the enzyme is an alkalophilic enzyme, the pH may be more alkaline, and a pH of about 9 to 12 may be favorable.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The method of the present invention is applicable to all pulp treatments that require a step of treating pulp with microorganisms and / or enzymes, such as bleaching of wood pulp (biobleaching) and deinking of pulp. Promotion of beating, modification of pulp,
It can be applied to saccharification of cellulose, production of cellooligosaccharides and the like.

[0022]

EFFECTS OF THE INVENTION According to the present invention, in the method of treating pulp with microorganisms and the like, hydrogen pulp is formed between the fibers because the pulp after cooking is kept in a wet state to act with enzymes and microorganisms. Since it prevents the so-called keratinization in which the fibers are strongly bound to each other and the contact with the enzyme is disturbed, the contact degree between the cellulose molecule, which is the main component of the pulp fiber, and the enzyme is increased. As a result, the efficiency of pulp treatment with enzymes and the like is improved.

[0023]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
Unless otherwise specified, “parts” and “%” described below mean “parts by weight” and “% by weight”, respectively.

Embodiment 1 FIG. Phanerochate chrysosporium lignin peroxidizer
Bleaching pulp with ze (LiP) 4 g of oxygen bleached pulp (manufactured by Nippon Paper Industries Co., Ltd.) collected in a wet state immediately after digestion was put in a 500 ml Erlenmeyer flask without drying, and then the method of Gold et al. LiP (0.007 U / ml) solution 200 m prepared according to (Arch.Biochm.Biophy.234, P353-362, 1984)
l and glucose and glucose oxidase (manufactured by Oriental Yeast) at 50 mM and 0.0 respectively.
5 U / ml was added, and the mixture was reacted at 37 ° C. and 140 rpm for 24 hours. After the reaction, a sheet having a basis weight of 40 g / m ² was prepared according to JIS P 8209, and
The result of measuring the whiteness according to P8123 is as shown in Table 1.

[0025]

[Table 1]

Comparative Example 1 Oxygen bleached pulp collected in a wet state immediately after cooking was once dried, then suspended again with pure water and disintegrated and then used, and the same operation as in Example 1 was carried out to prepare a sheet, which was white. The degree was measured. Table 1 shows the results
As shown in FIG.

Embodiment 2 FIG. Instead of bleaching treatment by LiP performed in the delignification Example 1 from the pulp by xylanase (0.007U / ml), after bleaching oxygen bleached pulp was xylanase treated under conditions shown in Table 2, in the table The same operation as in Example 1 was carried out except that the bleaching treatment by alkali extraction was carried out under the conditions shown. The Kappa number of the obtained pulp is measured according to JIS P 8211-1976, and the results are shown in Table 3.

[0028]

[Table 2]

[0029]

[Table 3]

Comparative Example 2 The oxygen bleached pulp collected in the wet state immediately after cooking was once dried, then suspended again in water and disintegrated, and then used in the same manner as in Example 2 to obtain a kappa of the obtained pulp. The value was measured. The results are as shown in Table 3.

Embodiment 3 FIG. Pulp using SKB-1152 strain isolated from nature
Bleaching test bacterium: wood-destroying basidiomycete S, which is a bacterium isolated from nature and having high lignin-degrading activity and pulp bleaching activity
Lignin degradation in pulp was performed using KB-1152 strain. This strain has been deposited at the Patent Microorganism Depositary Center, Institute of Biotechnology, Institute of Industrial Science and Technology (deposit number: FERM
P-13721), and its mycological properties are as shown below.

[0032] However, bacterial culture was carried out at 30 ° C. for 3 days in the above medium. The growth state was evaluated as being divided into weak, moderate and vigorous, and each was represented by +, ++ and +++.

Physiological and ecological properties: SKB-115 in the above-mentioned potato decoction-dextrose agar medium
The growth pH range during 3 days culture with 2 strains is 3 to 9
It is near. It does not grow at pH 2 or lower and 10 or higher.
The optimum pH is around 4-8. Further, the growth temperature range in the same medium is around 20 to 40 ° C, and growth cannot be carried out at 50 ° C or higher.

The SKB-1152 strain cultured in the above-mentioned medium at 30 ° C. and pH 5.6 for 4 days is characterized by white and thin felt-like flora. In addition, the SKB-1152 strain cultured at 30 ° C. for 3 days shows weak reactivity or negative to the phenol oxidase reaction.

Bleaching of Pulp with SKB-1152 Strain The SKB-1152 strain was grown at 30 ° C. in a potato dextrose broth liquid medium (trade name, manufactured by DIFCO) containing 0.4% potato decoction and 2% glucose. Culture was performed with reciprocal shaking for 5 days. Next, the bacterial cells were crushed with a Waring blender to prepare a bacterial cell suspension. On the other hand, the same oxygen bleached pulp as in Example 1 was converted to an absolute dry amount of 4 g and sterilized water 180
ml to a 500 ml Erlenmeyer flask, inoculated with 20 ml of the above-mentioned cell suspension, and at 37 ° C. and 140 rpm,
It was cultured for 24 hours. After culturing, a sheet having a basis weight of 40 g / m ² was prepared according to JIS P 8209, and
The result of measuring the whiteness according to 8123 is shown in Table 4.

[0036]

[Table 4]

Comparative Example 3. The oxygen bleached pulp collected in the wet state immediately after cooking was once dried, then suspended again in pure water and disintegrated and then used, and the same operation as in Example 3 was carried out to obtain the copper of the obtained pulp. The value was measured. The results are as shown in Table 4.

Claims (6)

[Claims] 1. A method of treating pulp, which comprises the step of treating pulp with microorganisms and / or enzymes, wherein the pulp used during the treatment has a water retention of 150 after digestion.
A method for treating pulp, which is ˜1000% non-dry pulp. 2. The method for treating pulp according to claim 1, wherein the microorganism is a white rot fungus. 3. The microorganism is a hemicellulase-producing bacterium,
The method for treating pulp according to claim 1. 4. The method for treating pulp according to claim 1, wherein the enzyme is a phenol oxidase. 5. The method of claim 1, wherein the enzyme is hemicellulase.
The method for treating pulp described in 1. 6. The method of treating pulp according to claim 1, wherein the pulp is kraft pulp and / or sulfite pulp.