JP3022513B1 - Pitch control method using microorganisms to prevent pulp brightness reduction - Google Patents

Abstract

A pitch control method for preventing a decrease in whiteness of a mechanical pulp, characterized by adding a microorganism and a specific reducing bleach to a mechanical pulp slurry to cause a biological reaction. provide. SOLUTION: By adding a microorganism and thiourea oxide or hydrosulfite or a mixture thereof to a mechanical pulp slurry, particularly, adding a thiourea oxide or hydrosulfite or a mixture thereof to a mixed reaction solution of the mechanical pulp slurry and the microorganism. Pitch decomposition is performed by adding the mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of adding a microorganism and a reducing bleach to a mechanical pulp slurry to cause a biological reaction, and more particularly, to a method of adding a reducing bleach to a mixture of a mechanical pulp slurry and a microorganism. The present invention relates to a pitch control method for preventing a decrease in whiteness of pulp, which is characterized by adding a compound to cause a biological reaction.

[0002]

2. Description of the Related Art A pitch control method using a microorganism includes a pitch control method using a mold (JP-A-6-24).
No. 5758) and a pitch control method using bacteria (Japanese Patent Application Laid-Open No. 9-119085) is known.

[0003]

A biochemical reaction by a microorganism or an enzyme has advantages over a physicochemical reaction. That is, reactions at normal temperature and normal pressure, mild reactions, substrate-specific reactions, and the like. However, pitch control by treating mechanical pulp with microorganisms significantly reduces the whiteness of the pulp during the reaction.

[0004] Whiteness is a very important property for pulp or paper, and a great deal of effort and effort is currently required to improve whiteness by one point.
Therefore, it is extremely disadvantageous in the production of paper pulp to bleach the microorganism-treated pulp having reduced whiteness and improve the whiteness.

On the other hand, biotechnology in pulp and paper is a new technical field, and research or development of technology for overcoming a number of weaknesses is far behind. The same applies to pitch control by microorganisms, and there is no research or technical development to prevent the decrease in whiteness.

An object of the present invention is to prevent a decrease in whiteness of pulp without losing the pitch resolution of microorganisms in a pitch control method by treating pulp with microorganisms.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems. As a result, in a mixed system of mechanical pulp slurry and microorganisms and a specific reducing bleaching agent, in particular, a thiourea oxide or hydrosulfite as a reducing bleaching agent is added to a mixed reaction system of mechanical pulp slurry and microorganisms. By performing a biological reaction in the coexistence thereof, without affecting the pitch resolution of microorganisms at all, and without reducing the whiteness of the pulp, it was found that pitch control is possible, The present invention has been completed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION To a mechanical pulp slurry, a broth after cultivation of bacteria is added, and thiourea oxide or hydrosulfite is added and reacted while shaking. After the completion of the reaction, a pulp sheet is prepared and the whiteness is measured.

Further, in order to confirm the degree of decomposition of the pitch in the pulp slurry, abietic acid, which is a kind of resin acid which is a kind of pitch, is measured by high performance liquid chromatography as an indicator substance.

The bacterium used in the present invention is a bacterium capable of decomposing a pitch component present in wood, which has been isolated from nature by a wide-ranging screening, and which is NPB-FERM No. 4805 strain, or Pseudomonas resinovorans. Mixtures of these bacteria can also be used. As described below, the use of NPB-4805 is particularly preferred from the viewpoint of the decomposition activity of the pitch component.

The bacteriological properties of the NPB-4805 strain are described below. 1. Morphological properties (1) Shape; Drought bacteria (2) Size; 0.6 × 1.3 μm (3) Polymorphism; − (4) Motility; + (5) Flagella; Polar flagella (6) Spores; (7) acid resistance;

2. Cultural properties (1) Broth agar culture Plate culture; growth is good. The colonies are circular and the plane is smooth. In addition, it protrudes in a semi-lens shape, and the peripheral edge is the entire edge. Near transparent white and glossy. (2) Gravy agar slope culture; growth is good. The colonies are filamentous and the surface is smooth. There is no projection, and the color is nearly transparent and glossy. (3) Broth liquid culture; growth is good, and no film or precipitate is formed. (4) Meat gelatin stab culture; does not liquefy. (5) Litmus milk; not reducible. Does not solidify.

3. Physiological properties (1) Gram stain;-(2) Reduction of nitrate; + (3) Denitrification reaction;-(4) MR test;-(5) VP test;-(6) Indole formation;-(7) Hydrogen sulfide; + (8) starch hydrolysis;- (11) pigment production;-(12) urease; + (Christensen medium) (13) oxidase; + (14) catalase; + (16) Attitude to oxygen; aerobic (17) OF test; O

The above bacteria are taxonomically pseudomonads (P.
seudomonas). As a similar strain, Pseudomonas resinovorans (Pseudom
onasresinovorans standard strain; ATCC-14235).
However, NPB-4805 is slightly smaller in size than ATCC-14235 (NPB-4805; 0.6 X 1.3 μm, ATCC-14235; 0.7 X
2.0 μm), which does not assimilate orthohydroxybenzoic acid and testosterone.
(NPB-4805; degradation rate 57.1%, ATCC-14235;
Degradation rate 41.5%), and different from the standard strain in terms of mycological properties.

Cell size is a very important index in taxonomics. As described above, it is more appropriate to consider that NPB-4805 has a particularly long rod smaller than the standard strain and is morphologically different from ATCC-14235. The availability of carbon sources is equally important. In addition, the significant difference in the assimilation activities of the alcohol: benzene extract of NPB-4805 and ATCC-14235 (the fraction mainly composed of pitch components) is attributed to the biochemical properties of both, namely the assimilation of pitch components. This implies that the enzymes involved are clearly different. From the above viewpoint, NPB-4805 is considered to be a different bacterium from Pseudomonas resinovorans.

The cultivation of the bacterium may be performed according to a commonly used culturing method. That is, the inoculum grown on the slope agar medium may be cultured in the main culture medium. Culture methods include stationary culture, shaking culture, aeration and stirring culture, solid culture, liquid culture,
Batch culture, continuous culture, high concentration culture, and the like are employed. In the present invention, shaking culture using a liquid or aeration and agitation culture is particularly desirable. Shaking or stirring speed
It should just be 100-200 rpm. When ventilation is performed, the condition of 0.5 to 1.0 VVM is preferable. When pure oxygen is used, it may be introduced into the medium at a rate of 0.1 to 0.3 VVM.

The medium used for the culture may be any of a natural medium, a semi-natural medium, and a synthetic medium. For shortening the culture time and maximizing the physiological activity of the bacterium, a semi-natural medium containing soybean peptone and casein peptone as the nitrogen source and glucose as the sugar source is most suitable. The medium can be sterilized by autoclave sterilization or filter sterilization.
After that, autoclaving at 120 ° C. for 15 minutes is generally used.

The culture temperature may be 4 to 40 ° C.
5-32 ° C is preferred. The pH may be in the range of 4-9, preferably 6-8. Usually, the culture is performed for 18 to 24 hours in a natural medium or a semi-natural medium.

The agent used in the present invention is thiourea oxide, hydrosulfite or a mixture thereof. This agent is a kind of reducing bleaching agent and is used under high temperature conditions in the pulp bleaching process. However, its use is less than that of chlorine-based chemicals or hydrogen peroxide in terms of economy and effect.

However, in the present invention, since pitch control by mechanical pulp treatment using bacteria is the ultimate purpose, a chemical such as chlorine-based or hydrogen peroxide having a bactericidal action even at a low concentration is reacted. Cannot coexist in the system. Also, it cannot be heated. In fact, when adding 0.067 g of hydrogen peroxide per 1 g of cells,
Bacteria completely lose their activity. Similar results are obtained when heating to 40 ° C. or higher.

However, in a room temperature reaction, the above-mentioned reduced bleach does not inhibit the activity of bacteria in a certain concentration range, and has an effect of preventing the whiteness of pulp from lowering. At the same time, the pitch component in the mechanical pulp slurry is also decomposed in the same manner as in the case where no drug is added, and the pitch control ability of bacteria can be maintained healthy.

The thiourea oxide is used in an amount of 0.067 to 1.667 g / g of bacterial cells and 0.067 / g of pulp.
It is added in the range of 02-0.050 g. When added in an amount of 1.667 g or more per gram of cells, an inhibitory effect on the activity of the bacterium occurs. Considering economic efficiency, 0.067-
Addition of 0.167 g is desirable. It is desirable to add 0.002-0.005 g to 1 g of pulp.

Hydrosulfite is used in an amount of 0.067-0.667 g / g of bacterial cells and 0.0067 g / g of pulp.
It is added in the range of 2-0.020 g. Addition of 0.667 g or more per 1 g of cells has an inhibitory effect on the activity of the bacterium. A desirable addition amount is 0.067-0.167 g / g of bacterial cells. 0.002-0.005g for 1g of pulp
Is desirable.

The reaction mixture of the pulp slurry and the bacteria is p
Although it may be in the range of H4-9, pH 6-8 is particularly preferable for effectively maintaining the pitch-degrading activity of bacteria.
The temperature may be in the range of 4 to 40 ° C, but it is particularly desirable to be in the range of 25 to 32 ° C in order to efficiently increase the biological activity of the bacteria.

Hereinafter, the present invention will be described with reference to examples.

[Example 1] Casein peptone 17 in 1 L
g, soy peptone 3 g, potassium monohydrogen phosphate 2.5
g, 2.5 g of glucose and 5.0 g of sodium chloride were adjusted to pH 7.0, and then 100 ml was dispensed into a 500 ml Sakaguchi Kolben, and sterilized in an autoclave at 120 ° C. for 15 minutes. One loopful of NPB-4805, previously cultured on a slope agar medium, was inoculated into each Kolben, and 30
Shaking culture was performed at 180 ° C. and 180 rpm for 18 hours.

A slurry of Japanese Akamatsu ground wood pulp was made into a slurry, which was then dispensed into 500 ml Sakaguchi Kolben.
5 ml of the above culture broth containing 3 mg / ml of the cells was inoculated to each kolben. The thiourea oxide solution which had been heated and dissolved in advance was added in an amount of 0.0
33-1.667 g, 0.001- per 1 g of pulp
0.050 g (10-500 ppm in reaction solution concentration) was added. The pulp concentration in the reaction mixture was 1%, and the final liquid volume per kolben was 50 ml. pH is 7.0. 30 ° C, 18
Shake at 0 rpm for 6 hours.

From the above reaction solution, 10 ml was sampled, 10 ml of ethanol was added, mixed well, and left overnight. Then, an appropriate amount was sampled and centrifuged. 20 μl of the supernatant was analyzed by high performance liquid chromatography. The degree of pitch degradation was evaluated by the content of abietic acid, a kind of resin acid, which is the main component, in the pulp.

The analysis conditions are as follows. Column: Inartosil-2 (4.6 x 250mm)
(Gascro Industry Co., Ltd.) Solvent: acetonitrile: distilled water: acetic acid = 75: 25:
0.1 Flow rate: 1 ml / min Detection: UV 241 nm

On the other hand, using the pulp after the reaction, 1.
A hand-made sheet of 2 g was prepared, and the whiteness was measured with a hunter.

Example 2 Casein Peptone 1 in 1 L
7 g, soy peptone 3 g, potassium monohydrogen phosphate 2.5
g, 2.5 g of glucose and 5.0 g of sodium chloride were adjusted to pH 7.0, and then 100 ml was dispensed into a 500 ml Sakaguchi Kolben, and sterilized in an autoclave at 120 ° C. for 15 minutes. One loopful of NPB-4805, previously cultured on a slope agar medium, was inoculated into each Kolben, and 30
Shaking culture was performed at 180 ° C. and 180 rpm for 18 hours.

A slurry of Japanese Akamatsu ground wood pulp was slurried and then dispensed into 500 ml Sakaguchi Kolben.
5 ml of the above culture broth containing 3 mg / ml of the cells was inoculated to each kolben. The hydrosulfite solution which had been heated and dissolved in advance was added in an amount of 0.03 / g of cells.
3-0.667 g, 0.001-0.
020 g (10-200 ppm in reaction solution concentration). The pulp concentration of the reaction mixture is 1%,
The liquid volume per kolben was adjusted to 50 ml. pH is 7.0. This is 30 ° C., 180 rpm
For 6 hours.

From the above reaction solution, 10 ml was sampled, 10 ml of ethanol was added, mixed well, and left overnight. Then, an appropriate amount was sampled and centrifuged. 20 μl of the supernatant was analyzed by high performance liquid chromatography to determine the content of abietic acid in the pulp. The analysis conditions are the same as in Example 1.

On the other hand, using the pulp having undergone the reaction,
A hand-made sheet of 2 g was prepared, and the whiteness was measured with a hunter.

Comparative Example 1 Japanese Akamatsu groundwood pulp was made into a slurry and then dispensed into 500 ml Sakaguchi Koruben. The pulp concentration is 1%, and the liquid volume per kolben is 50 ml. pH is 7.0.
This was shaken at 30 ° C. and 180 rpm for 6 hours.

The content of abietic acid was measured in the same manner as in the examples. On the other hand, a 1.2 g hand-made sheet was prepared using the pulp after the reaction, and the whiteness was measured with a hunter.

[Comparative Example 2] A slurry of Japanese Akamatsu groundwood pulp was made into a slurry, which was then dispensed into 500 ml Sakaguchi corbens, and 5 ml each of the above-mentioned medium without cells was inoculated into each corben. Pulp concentration of mixture is 1%
And the final liquid volume per kolben is 50 ml. pH is 7.0. This is 30 ° C., 180 rpm
For 6 hours.

The content of abietic acid and the whiteness of the pulp sheet were measured in the same manner as in Example 1.

Comparative Example 3 Casein Peptone 1 in 1 L
7 g, soy peptone 3 g, potassium monohydrogen phosphate 2.5
g, 2.5 g of glucose and 5.0 g of sodium chloride were adjusted to pH 7.0, and then 100 ml was dispensed into a 500 ml Sakaguchi Kolben, and sterilized in an autoclave at 120 ° C. for 15 minutes. One loopful of NPB-4805, previously cultured on a slope agar medium, was inoculated into each Kolben, and 30
Shaking culture was performed at 180 ° C. and 180 rpm for 18 hours.

A slurry of Japanese Akamatsu ground wood pulp was added to a 500 ml Sakaguchi Kolben slurry.
5 ml of the above culture broth containing bacterial cells / ml
Each l was inoculated. The pulp concentration of the reaction mixture is 1%, and the final volume per kolben is 50 ml.
pH is 7.0. This is 6 ° C at 30 ° C and 180 rpm.
Shake time.

The measurement of abietic acid and pulp sheet is as follows:
According to Example 1. Table 1 shows the above results. In the table, G
P indicates groundwood pulp, and ABA indicates abietic acid.

[Table 1] The results in Table 1 show that the examples of the present invention decompose abietic acid in groundwood pulp at a degradation rate of 98.0% without reducing the whiteness of the pulp sheet.

[0041]

According to the present invention, thiourea oxide or hydrosulfite as a reducing bleach is added to a mixed reaction system of a mechanical pulp slurry and a microorganism, and a biological reaction is performed in the coexistence thereof. The pitch can be controlled without affecting the pitch resolution of microorganisms at all and without reducing the whiteness of the pulp.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C12S 3/08 C12S 3/08 (56) References JP-A-9-119085 (JP, A) JP-B-48-38328 (JP) , B1) JP 42-16326 (JP, B1) JP 6-501062 (JP, A) JP 6-506021 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB Name) D21C 9/08-9/10 C12N 1/00 C12N 1/20 C12S 3/08

Claims (6)

(57) [Claims] 1. A pitch control method for preventing a decrease in whiteness of pulp, comprising adding a microorganism and a reducing bleach to a mechanical pulp slurry to cause a biological reaction. 2. The pitch control method according to claim 1, wherein the mechanical pulp slurry and the microorganism are mixed, and a reducing bleach is added to the mixture. 3. The method of claim 2, wherein the microorganism is Pseudomonas.
nas) A bacterium belonging to the genus
2. The method according to claim 1, wherein the method is selected from the group consisting of one or more of NPB-4805 strain of FERM P-16263 and Pseudomonas resinovorans. 4. The method of claim 1, wherein said reducing bleach is selected from the group consisting of thiourea oxide, hydrosulfite or mixtures thereof. 5. The thiourea oxide is 1 g of bacterial cells.
2. The method according to claim 1, wherein 0.067 to 1.667 g of the pulp and 0.002 g to 0.050 g of the pulp are added. 6. The method according to claim 1, wherein said hydrosulfite is added in a ratio of 0.067-0.667 g per 1 g of cells and 0.002 g-0.020 g per 1 g of pulp. The method of claim 1.