JP2757106B2 - Microorganism for pulp bleaching and pulp bleaching method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel microorganism having excellent pulp bleaching performance and a method for bleaching pulp using the microorganism.

[0002]

2. Description of the Related Art Conventionally, chlorinated chemicals such as chlorine and chlorine dioxide are usually used for bleaching pulp. However, dioxin, which is an extremely toxic substance, is bleached with these chlorinated chemicals. In recent years, it has become clear that by-products are produced, and there is a demand for a reduction in the amount used. In addition, several methods have been devised as bleaching chemicals to replace these chlorine-based chemicals, but biobleaching, in which pulp is bleached by microorganisms or enzymes, is one of the most effective methods among them. Have been.

[0003] As a biobleaching method, a method of using, in particular, white rot fungi having the ability to degrade lignin for pulp bleaching has been studied. Specific examples of the white rot fungi that have been studied include, for example, Coriolus
versicolor, Kaitake mushroom (Lenz)
items betuluna, oyster mushroom (Pleur)
otus ostreatus, Fanelocate chrysosporium ( Phanerochaete chr)
yssoporium). However, the above-mentioned bacteria have insufficient lignin-decomposing activity, so that they were insufficient for use in biobleaching.

Further, as shown in, for example, JP-A-3-269188, the optimum temperature for bleaching unbleached pulp by treating it with white rot fungi is about 28 ° C. In view of the above, processing at a higher temperature is desirable from the viewpoint of shortening the bleaching time. Therefore, the above-mentioned fungi, which have been studied for the purpose of conventional pulp bleaching at about 28 ° C., are insufficient for use in the bleaching method in industrial pulp production, and degrade lignin even under higher temperature conditions. Bacteria that have high activity and can greatly improve whiteness have been demanded.

Accordingly, the present inventors have studied methods for separating and screening such pulp bleached microorganisms from nature, and have developed new methods for separating and screening bacteria (Japanese Patent Application No. 5-85731).
As a result of searching for a bacterium having a high pulp bleaching activity using these methods, not only can the pulp whiteness be significantly improved, but also a new microorganism SKB- which exhibits its activity at a higher temperature than conventional microorganisms. Successful isolation of 185 strains,
The present invention has been completed.

[0006]

Accordingly, it is a first object of the present invention to provide a novel microorganism having excellent pulp bleaching performance at high temperatures. A second object of the present invention is to provide an industrial pulp bleaching method without using a chlorine-based chemical.

[0007]

The above objects of the present invention have been attained by a microorganism SKB-185 strain excellent in pulp bleaching performance and a pulp bleaching method using the same.
The bacteriological properties of the novel microorganism SKB-185 of the present invention will be described below. (1) Growth state in medium

[0008]

[Table 1]

(2) Physiological and ecological properties Growth pH range: Growing around pH 3-9, not growing below pH 2 and above 10. The optimal pH for growth is 4-7
Around (potato decoction, dext, loin agar,
(Culture at 30 ° C for 4 days). Temperature range for growth: grows around 24-40 ° C and does not grow above 45 ° C (potato decoction / dextrose agar medium, pH 5.6, cultured for 4 days). Phenol oxidase reaction: positive (30 ° C, 3
Days culture). Characteristics of the flora: white and felt-like (potato decoction / dextrose agar medium, 30 ° C., pH 5.6, cultured for 4 days).

The physiological and ecological properties and the mycological properties such as the growth state in each medium were examined in detail, but could not be identified with known bacteria. However, as is clear from the examples described later, the present bacterium is superior in bleaching activity to white rot fungi conventionally known as lignin-degrading bacteria, and the difference in the activity is particularly remarkable at high temperatures. .

Since microorganisms having such excellent bleaching activity have not been known so far, the present strain was identified as a new strain and named SKB-185 strain. Deposited at the Microbial Depositary Center (Deposit No .: FERM-13530). The exact location of this strain in the taxonomic system is still difficult to identify at this time due to some unclear points.
We have to wait for future research.

Hereinafter, a method for isolating the SKB-185 strain used in the present invention will be described. The SKB-185 strain is cultured by inoculating a medium containing lignin or a pulp in which lignin remains, with a microorganism source isolated from decay material or soil, and separating and selecting from a decolorized zone portion of the medium. Here, kraft lignin, sulfite lignin and the like can be used as lignin, and chemical pulp such as kraft pulp can be used as lignin residual pulp.

Examples of the medium include a liquid medium obtained by simply adding a culture solution to pulp and a solid medium obtained by solidifying pulp with agar or the like. The preparation of the culture medium and the selection of lignin-degrading bacteria in the above-mentioned separation / selection method may be appropriately performed based on a conventionally known method. The above separation / selection method is not only simpler and more accurate than the conventional method based on phenol oxidase detection, but also separates / selects lignin-degrading bacteria from microorganism sources separated from decay materials and soil. The feature is that it is possible.

Next, the novel microorganism SKB-18 of the present invention is described.
The pulp bleaching method using five strains will be described. The pulp bleaching method using this strain is basically a method of inoculating pulp with a fungus and culturing it for a predetermined period, and the conditions and the like are not particularly limited. The pulp used in the present invention may be of any type such as chemical pulp and mechanical pulp.

[0015] The shape of the pulp may be any shape as long as the bacteria grow and are easily bleached. Further, the pulp concentration during the culturing is preferably in the range of 20 to 60% from the viewpoints of air permeability and growth of bacteria. 2
If it is less than 0%, the growth of bacteria is observed, but the bleaching efficiency of the pulp is reduced. On the other hand, if it is more than 60%, the growth of the bacteria is deteriorated and the bleaching ability of the pulp is reduced.

The pH and temperature during the cultivation are different depending on other conditions and are not particularly limited as long as they are within the range described in the physiological properties of the present bacterium. Usually, the pH and the temperature are within the range of 4 to 7. Yes, the culture temperature is preferably in the range of 25 ° C. to 40 ° C., and particularly good results can be obtained at around 37 ° C. Further, various nutrients may be added at the time of culturing, if necessary, in order to shorten the time required for bleaching the pulp.

As described above, the pulp may be bleached using the fungus in the same manner as in the conventional method, and no special consideration is required. In addition, as apparent from its bleaching performance, the present bacterium also has a high lignin-decomposing activity, so that the bacterium can be used in various wood utilization industries requiring delignification other than pulp bleaching. In this case, as in the case of pulp bleaching, the treatment may be carried out by inoculating the present bacterium into a medium containing the desired woody material and culturing it for a predetermined period.

[0018]

Industrial Applicability The microorganism of the present invention has much better pulp bleaching performance especially in a high temperature region than conventional microorganisms. It is possible to use it. Further, applications other than pulp bleaching, such as pulp manufacturing processes, pulp wastewater treatment processes, and wood saccharification processes, are also possible.

[0019]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

Embodiment 1 SK in potato dextrose broth liquid medium (manufactured by DIFCO) containing 0.4% potato decoction and 2% glucose
The B-185 strain was allowed to stand and cultured for one week, and the formed bacterial cell mat was pulverized with a Waring blender.
A bacterial cell suspension was added to oxygen bleached pulp (OKP, manufactured by Sanyo Kokusaku Pulp) sterilized by heating for 5 minutes so that the final pulp concentration was 20%, and the mixture was allowed to stand at 30 ° C for 7 days. Thereafter, 500 ml of water was added thereto, and the mixture was defibrated by a mixer to prepare a hand-made sheet. The whiteness of the sheet was measured using a Hunter whiteness meter (JIS P-8123), and at the same time, the kappa number (JISP-8211-1976) was also measured.
The points of increase in whiteness are as shown in Table 2.

[0021]

[Table 2]

Comparative Examples 1 and 2. SK used in Example 1
Instead of the B185 strain, representative lignin-degrading bacteria, Coriolus versicolor (Comparative Example 1) and Phanerochaete chrysosporium (Phanerochaete chry)
sosporium) (Comparative Example 2), respectively.
The same operation as described above was performed. The points of increase in whiteness are shown in Table 2.

Embodiment 2 FIG. The SKB-185 strain was statically cultured for one week in a potato dextrose broth liquid medium (manufactured by DIFCO) containing 0.4% potato decoction and 2% glucose, and the resulting cell mat was pulverized with a Waring blender. A bacterial cell suspension was added to oxygen bleached pulp (OKP, manufactured by Sanyo Kokusaku Pulp) sterilized by heating at 120 ° C. for 15 minutes so that the final pulp concentration was 20%.
For 7 days. Thereafter, 500 ml of water was added thereto, and the mixture was defibrated by a mixer to prepare a hand-made sheet. The whiteness and kappa number of the sheet were measured in the same manner as in Example 1. The points of increase in whiteness are shown in Table 2.

Comparative Examples 3 and 4. Instead of the SKB-185 strain used in Example 2, a typical lignin-degrading bacterium, Kawatake (Coriolu) was used.
s versicolor) (Comparative Example 3) and Fanelocate chrysosporium (Phanerochaet)
e chrysosporium) (Comparative Example 4), except that the same operation as in Example 2 was performed. The points of increase in whiteness are as shown in Table 2. Table 2 above
As is clear from the results, the novel microorganism of the present invention
The bleaching activity is remarkably superior to the conventional bacteria, and it can be seen that the whiteness can be greatly improved.

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Claims (2)

(57) [Claims] A microorganism SKB-1 having excellent pulp bleaching performance.
85 shares. 2. A microorganism SKB-1 having excellent pulp bleaching performance.
A pulp bleaching method comprising inoculating and cultivating 85 strains of pulp.