EP0407421A1 - Procedure for bleaching cellulose pulp. - Google Patents

Procedure for bleaching cellulose pulp.

Info

Publication number
EP0407421A1
EP0407421A1 EP89903748A EP89903748A EP0407421A1 EP 0407421 A1 EP0407421 A1 EP 0407421A1 EP 89903748 A EP89903748 A EP 89903748A EP 89903748 A EP89903748 A EP 89903748A EP 0407421 A1 EP0407421 A1 EP 0407421A1
Authority
EP
European Patent Office
Prior art keywords
pulp
enzyme
bleaching
chlorine
bleached
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP89903748A
Other languages
German (de)
French (fr)
Other versions
EP0407421B1 (en
Inventor
Mirja Salkinoja-Salonen
Marja Vaheri
Marja Koljonen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Genencor International Europe Oy
Original Assignee
Cultor Oyj
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=8526077&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0407421(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Cultor Oyj filed Critical Cultor Oyj
Publication of EP0407421A1 publication Critical patent/EP0407421A1/en
Application granted granted Critical
Publication of EP0407421B1 publication Critical patent/EP0407421B1/en
Anticipated expiration legal-status Critical
Revoked legal-status Critical Current

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds
    • D21C9/14—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds with ClO2 or chlorites
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1026—Other features in bleaching processes

Definitions

  • the present invention concerns a procedure for bleaching cellulose pulp derived from hardwood, a bleaching chemical containing chlorine being used in said procedure.
  • Cellulose pulp obtained by sulphate cooking in particular is brown, mainly owing to lignin remaining in the pulp.
  • the present understanding is that this residual lignin is linked to hemicellulose with covalent bonds. Lignin is removed by bleaching, whereby the pulp is rendered usable for high-quality paper and cardboard products.
  • Bleaching is usually accomplished in a multi-stage process in which the pulp is alternately treated with oxidizing, lignin-decomposing chemicals and with chemicals dissolving the substances generated as decomposition products.
  • substances containing chlorine have been used for oxidizing chemicals, such as pure chlorine gas, chlorine dioxide or sodium or potassium hypochlorite, although other types of oxidizing bleaching agents containing no chlorine are also known.
  • alkali solutions have been used for extraction chemicals removing the decomposition products.
  • the object of the present invention is therefore to devise a problem solution by which the residual chlorine content of bleached cellulose pulp made of hardwood can be reduced from the present level.
  • the invention is characterized in that the residual chlorine content is lowered by subjecting the pulp to an enzyme treatment.
  • the enzyme treatment may be carried out at an arbitrary stage of the bleaching process.
  • the pulp may be treated with enzyme in connection with one of the oxidizing steps or extraction steps (alkali steps) of the process or between, the respective steps, prior to said bleaching steps, or not until after said steps.
  • the enzyme to be used is advantageously hemicellulase, cellulase, esterase or a mixture of these, and as suitable enzyme products may be mentioned Multi Stamm L 250 and Multi Stamm K.
  • the temperature of the enzyme treatment may be in the range of 10 to 90°C, preferably 40 to 70°C, and pH within the range of 3.0 to 7.5, preferably 4.0 to 6.0.
  • a further object of the invention is the use of enzyme towards reducing the residual chlorine content of bleached cellulose pulp made from hardwood.
  • Suitable enzymes include hemicel lulases, cellulases and esterases or mixtures of these, e.g. the enzyme products Multifect L 250 and Multifect K.
  • Use of the enzyme is implemented, according to the invention, in the manner set forth in the preceding description of the bleaching procedure.
  • enzyme as taught by the invention relates to reduction of the residual chlorine content in bleached cellulose pulp meant to be processed into foodstuff packaging cardboard or paper. This is because the increasingly stricter provisions regarding residual chlorine concern particularly said cardboard and paper brands, which end up as waste for disposal in waste incineration plants, where the chlorine contained in them may, when it burns, produce highly toxic dioxin.
  • Hemicellulases e.g. xylanase 0 to 10- U per kg of mass 1) ⁇ -xylosidase 0 to 20,000 U per kg of mass 2)
  • the enzyme-treated pulp stock batch and the reference batch were next subjected to bleaching, which took place in five consecutive oxidizing and extracting steps.
  • chlorine and chlorine dioxide were used for chemicals
  • sodium hydroxide in the second step sodium hydroxide
  • chlorine dioxide in the third step sodium hydroxide
  • sodium hydroxide in the fourth step sodium hydroxide
  • chlorine dioxide in the fifth step chlorine dioxide.
  • Table lb are presented the total chlorine quantities used in bleaching, and the results of measurement found with the bleached pulp batches.
  • Residual chlorine content (mg/g) 0.845 1.270
  • Bleached birch sulphate pulp was used in this experiment.
  • the pulp had been bleached using for bleaching chemicals in the first step chlorine (90%) and chlorine dioxide (10%), in the second step sodium hydroxide and in the third step oxygen.
  • the bleached pulp was subjected to enzyme treatment under identical conditions, and using the same enzyme, as in Example 1. After treatment, the pulp was washed with water and dried at room temperature. The residual chlorine content was measured both of the enzyme-treat- ed pulp and of the untreated, original bleached sulphate pulp, the result 1.18 being found for the former and 1.56 mg/g for the latter. Thus, the residual chlorine content of bleached pulp could be substantially lowered by means of enzyme treatment.
  • the test demonstrates that the desired result is attained with the invention also in case the cellulose pulp is first bleached and treated with enzyme only thereafter.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
  • Investigating Or Analysing Biological Materials (AREA)
  • Hard Magnetic Materials (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)
  • Detergent Compositions (AREA)
  • Preparation Of Compounds By Using Micro-Organisms (AREA)

Abstract

The present invention concerns a procedure for bleaching cellulose pulp obtained from hardwood, wherein bleaching chemical containing chlorine is used. The essential feature of the invention is that the residual chlorine content of the bleached pulp is reduced by subjecting the pulp to enzyme treatment. With the enzyme especially the removal from the pulp of chlorine-binding extractive substances present in hardwood pulp is promoted. The invention furthermore concerns the use of enzyme towards lowering the residual chlorine content of bleached cellulose pulp made from hardwood. Such cellulose pulp is particularly contemplated which will be converted into foodstuff package cardboard or paper, which are commonly disposed of by burning. Lowered chlorine content reduces the risk of producing toxic dioxin at the incineration step.

Description

PROCEDURE FOR BLEACHING CELLULOSE PULP
The present invention concerns a procedure for bleaching cellulose pulp derived from hardwood, a bleaching chemical containing chlorine being used in said procedure.
Cellulose pulp obtained by sulphate cooking in particular is brown, mainly owing to lignin remaining in the pulp. The present understanding is that this residual lignin is linked to hemicellulose with covalent bonds. Lignin is removed by bleaching, whereby the pulp is rendered usable for high-quality paper and cardboard products.
Bleaching is usually accomplished in a multi-stage process in which the pulp is alternately treated with oxidizing, lignin-decomposing chemicals and with chemicals dissolving the substances generated as decomposition products. Above all, substances containing chlorine have been used for oxidizing chemicals, such as pure chlorine gas, chlorine dioxide or sodium or potassium hypochlorite, although other types of oxidizing bleaching agents containing no chlorine are also known. For extraction chemicals removing the decomposition products, alkali solutions have been used.
In the course of reacting, chemicals containing chlorine cause chlorination of lignin, as well as of such fatty and resinous acids which are present in the pulp. Therefore chlorophenσls are produced from lignin in the bleaching process, which end up in the bleaching waste water escaping from the pulp. Chlorine is further bound to those residues of lignin and acids which are still left in the cellulose pulp after completed bleaching. In recent time this residual chlorine has been increasingly regarded as an environmental detri ment at the phase when paper or cardboard products made from the pulp end up as waste, and restriction imposed on the allowable chlorine content of pulp are therefore to be expected on the near future. Such restrictions would particularly concern pulp used for foodstuff cardboard which ends up in waste incineration plants and on dumps. This problem is particularly salient in the case of pulp made from hardwood, e.g. from birch or eucalyptus wood, which has a high content of chlorine-binding extractive substances.
The object of the present invention is therefore to devise a problem solution by which the residual chlorine content of bleached cellulose pulp made of hardwood can be reduced from the present level. The invention is characterized in that the residual chlorine content is lowered by subjecting the pulp to an enzyme treatment.
It has already been observed in earlier studies that it is possible with the aid of enzymes to detach lignin from cellulose. The conclusion herefrom is that when pulp obtained in a cooking process is first treated with enzyme, the use of chlorine-containing bleaching chemicals in the subsequent bleaching step can be eliminated, partly or even totally. In the present invention now the observation has been made that when said enzyme treatment is combined with a bleaching process using chlorine chemicals in substantially standard manner, the result will be cellulose pulp having a residual chlorine content which is substantially lowered from what it would be in the absence of enzyme treatment.
According to the invention, the enzyme treatment may be carried out at an arbitrary stage of the bleaching process. Thus, the pulp may be treated with enzyme in connection with one of the oxidizing steps or extraction steps (alkali steps) of the process or between, the respective steps, prior to said bleaching steps, or not until after said steps. The enzyme to be used is advantageously hemicellulase, cellulase, esterase or a mixture of these, and as suitable enzyme products may be mentioned Multifekt L 250 and Multifekt K. The temperature of the enzyme treatment may be in the range of 10 to 90°C, preferably 40 to 70°C, and pH within the range of 3.0 to 7.5, preferably 4.0 to 6.0.
A further object of the invention is the use of enzyme towards reducing the residual chlorine content of bleached cellulose pulp made from hardwood. Suitable enzymes include hemicel lulases, cellulases and esterases or mixtures of these, e.g. the enzyme products Multifect L 250 and Multifect K. Use of the enzyme is implemented, according to the invention, in the manner set forth in the preceding description of the bleaching procedure.
Quite specifically the use of enzyme as taught by the invention relates to reduction of the residual chlorine content in bleached cellulose pulp meant to be processed into foodstuff packaging cardboard or paper. This is because the increasingly stricter provisions regarding residual chlorine concern particularly said cardboard and paper brands, which end up as waste for disposal in waste incineration plants, where the chlorine contained in them may, when it burns, produce highly toxic dioxin.
The appropriate enzyme activities (U = unit of activity) of various enzyme categories that can be used in the present invention are within the following limits! Hemicellulases: e.g. xylanase 0 to 10- U per kg of mass 1) β-xylosidase 0 to 20,000 U per kg of mass 2)
Esterasess 0 to 100,000 U per kg of mass
Cellulases:
Filter paper activity 0 to 20,000 U per kg of mass 3) CMC activity 0 to 500,000 U per kg of mass 4) β-glucosidase 0 to 20,000 U per kg of mass 5)
β-glucanase 0 to 500,000 U per kg of mass 6)
1) Khan, A.W., Tremblay, D., LeDuy, A., Enzyme Microb. Technol., 8 (1986) 373-377
2) F. Delyn, M. Claeyssens, J. van Beeumen, C.K. de Bruyπe, Can. J. Biochem 56 43 (1987)
3) Ghose, T.K., Patnak, A.N., Bisaria, V.S., Symposium of Enzymatic Hydrolysis of Cellulose, Bailey, M., Enari, T.M., Linko, M. , Eds. (SITRA, Aulanko, Finland, 1975), 111-136
4) Mandels, M., Weber, J., Adv. Chem. Ser. 95 (1969) 391-413
5) Berghem, Ler, Pettersson, Eur. J. Biochem 37 (1973) 21-30
6) Sugar determinations Miller, G.L., Anal. Chem. 31 1959) 426-428
The invention is described more closely in the following with the aid of two embodiment examples based on laboratory experiments.
Example 1
220 g pulp dry matter from birch sulphate cooking (dry weight content of pulp 10%) were suspended into 50 mM of Na nitrate buffer pH 5 in such manner that the ultimate concentration of the mixture was 2.3% . Multifect K enzyme was added so that the xylanase activity of the mixture was 56 U per g of pulp dry matter. The temperature during the enzyme treatment was 39°C and treatment time, 20 h. The pulp was filtered after enzyme treatment with a Buchner funnel and the pulp cake thus obtained was washed with ion-exchanged water so as to obtain a washing ratio of 28.
A similar pulp batch was treated as reference in the same manner but without enzyme addition.
In Table la below are presented results of measurement from said two pulp stock batches, in this step of treatment.
TABLE la
Enzyme treated No enzyme treatment
(Reference batch)
Kappa number 16.8 21
DKM extract content (X of dry matter) 0.27 0.23
(dm3/kg) 1065 1280
The enzyme-treated pulp stock batch and the reference batch were next subjected to bleaching, which took place in five consecutive oxidizing and extracting steps. In the first step chlorine and chlorine dioxide were used for chemicals, in the second step sodium hydroxide, in the third step chlorine dioxide, in the fourth step sodium hydroxide, and in the fifth step chlorine dioxide. In The following Table lb are presented the total chlorine quantities used in bleaching, and the results of measurement found with the bleached pulp batches.
TABLE lb
Enzyme treated No enzyme treatment
(Reference batch)
Dosage of active chlorine,
(mg/g of pulp dry matter) (2 × kappa) 33.6 42
Yield 93.6% 97.5%
DKM extract content, % of dry matter 0.26 0.29
Consistency (dm3/kg) 1035 1210
Residual chlorine content (mg/g) 0.845 1.270
The results reveal that the residual chlorine content after bleaching is clearly lower in the enzyme-treated cellulose pulp than in the pulp which received no enzyme treatment. It is further seen that no decisive weakening of strength values took place in the enzymetreated pulp. Example 2
In this experiment three pulp stock batches obtained by birch sulphate cooking were used, which had the same consistency as those in the preceding Example 1. Two batches were treated with enzyme as presented above, while the third batch constituted a reference batch. The enzymes differed from those used in Example 1 in that with one of them (in Batch 1) in the mixture was achieved, in addition to xylanase activity 56 U per g of pulp dry matter, cellulase activity 1.5 U per g of pulp dry matter and in the other (Batch 2), in addition to xylanase activity 56 U per g of pulp dry matter, cellulase activity 1.1 U per g of pulp dry matter. The results after enzyme treatment are shown in Table I la.
TABLE Ila
Enzyme pre- Enzyme pre- No enzyme treatment treatment treatment (Reference batch) (Batch 1) (Batch 2)
Kappa number 15.8 15.0 18.8
DKM extract content (% of dry matter) 0.32 0,32 0.26
(dm3/kg) 1025 1130 1305
The pulp batches were hereafter bleached with chlorine chemicals and sodium hydroxide as in Example 1. The total chlorine dosage in mg/g was 2 × the kappa number in each case. The results after bleaching are shown in Table lib. TABLE l Ib
Enzyme pre- Enzyme pre- No enzyme treatment treatment treatment (Reference batch) (Batch 1) (Batch 2)
Yield 94.6 97,4
DKM extract content
(% of dry matter) 0.36 0,35 0.37
Consisteney (dm3/kg) 980 1065 1210
Total chlorine content
(mg/g) 1.15 1.15 1.46
The results reveal in this instance, too, that enzyme treatment substantially reduces the residual chlorine content of the bleached pulp.
Example 3
Bleached birch sulphate pulp was used in this experiment. The pulp had been bleached using for bleaching chemicals in the first step chlorine (90%) and chlorine dioxide (10%), in the second step sodium hydroxide and in the third step oxygen.
The bleached pulp was subjected to enzyme treatment under identical conditions, and using the same enzyme, as in Example 1. After treatment, the pulp was washed with water and dried at room temperature. The residual chlorine content was measured both of the enzyme-treat- ed pulp and of the untreated, original bleached sulphate pulp, the result 1.18 being found for the former and 1.56 mg/g for the latter. Thus, the residual chlorine content of bleached pulp could be substantially lowered by means of enzyme treatment.
The test demonstrates that the desired result is attained with the invention also in case the cellulose pulp is first bleached and treated with enzyme only thereafter.
It is obvious to a person skilled in the art that different embodiments of the invention are not confined to what has been presented in the foregoing by way of example, and that they may vary within the scope of the claims following below. For instance, one may in the first step of conventional five-step chlorine bleaching use either chlorine alone or chlorine in mixture with chlorine dioxide. It is also possible to make the time during which the enzyme is allowed to act considerably less than the mentioned time of 20 hours. Treatment tomes of a few hours, or even shorter than one hour, are thus conceivable, depending on the enzyme chosen and on its activity.

Claims

1. A procedure for bleaching cellulose pulp obtained from hardwood, wherein bleaching chemicalk containing chlorine is used, characterized in that the residual chlorine content of the bleached pulp is reduced by subjecting the pulp to enzyme treatment.
2. Procedure according to claim 1, characterized in that the pulp is treated with enzyme either before or after the bleaching treatment.
3. Procedure according to claim 1, characterized in that the enzyme treatment takes place within the temperature range 10 to 90ºC, preferably 40 to 70°C, and at pH 3.0 to 7.5, preferably 4.0 to 6.0.
4. Procedure according to any one of the preceding claims, characterized in that the enzyme which is used is hemicellulase, cellulase, esterase or a mixture of these.
5. Procedure according to claims 2-4, characterized in that to unbleached pulp obtained by birch sulphate cooking is added enzyme which is allowed to act, whereafter the pulp is subjected to bleaching comprising consecutive oxidizing and extracting steps, using for bleaching chemicals in the oxidizing steps chlorine gas and/or chlorine dioxide and in the extracting steps, sodium hydroxide.
6. Procedure according to claim 5, characterized in that the bleaching is a five-step chlorine bleaching.
7. Procedure according to claims 2-4, characterized in that pulp obtained by birch sulphate cooking is bleached in consecutive oxidizing and extracting steps, using in the first step chlorine gas and/or chlorine dioxide and in the subsequent extracting step, sodium hydroxide, and that after bleaching to the pulp suspension thus obtained is added enzyme, which is allowed to act the desired time.
8. The use of enzyme for lowering the residual chlorine content of bleached cellulose pulp made from hardwood.
9. The use according to claim 8 of hemicellulase, cellulase, esterase or a mixture of these towards lowering the residual chlorine content of bleached cellulose pulp.
10. The use of enzyme according to claim 8 or 9 towards lowering the residual chlorine content of bleached cellulose pulp that is going to be processed to become foodstuff package cardboard or paper.
EP89903748A 1988-03-14 1989-03-13 A method for reducing residual chlorine content in hardwood pulp Revoked EP0407421B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FI881192A FI81395B (en) 1988-03-14 1988-03-14 FOERFARANDE FOER BLEKNING AV CELLULOSAMASSA.
FI881192 1988-03-14
PCT/FI1989/000045 WO1989008738A1 (en) 1988-03-14 1989-03-13 Procedure for bleaching cellulose pulp

Publications (2)

Publication Number Publication Date
EP0407421A1 true EP0407421A1 (en) 1991-01-16
EP0407421B1 EP0407421B1 (en) 1996-03-13

Family

ID=8526077

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89903748A Revoked EP0407421B1 (en) 1988-03-14 1989-03-13 A method for reducing residual chlorine content in hardwood pulp

Country Status (12)

Country Link
EP (1) EP0407421B1 (en)
JP (1) JPH03505758A (en)
AT (1) ATE135429T1 (en)
AU (1) AU626846B2 (en)
BR (1) BR8907314A (en)
CA (1) CA1334581C (en)
DE (1) DE68925967T2 (en)
DK (1) DK175185B1 (en)
FI (1) FI81395B (en)
NO (1) NO174722C (en)
NZ (1) NZ228308A (en)
WO (1) WO1989008738A1 (en)

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5298405A (en) * 1986-04-30 1994-03-29 Alko Limited Enzyme preparations with recombinantly-altered cellulose profiles and methods for their production
FI90888B (en) * 1989-02-14 1993-12-31 Enso Gutzeit Oy Method for bleaching cellulose pulp
FI86896B (en) * 1989-05-04 1992-07-15 Enso Gutzeit Oy FOERFARANDE FOER BLEKNING AV CELLULOSAMASSA.
DK420289D0 (en) * 1989-08-25 1989-08-25 Novo Nordisk As METHOD OF TREATING LIGNOCELLULOSE PULP
NZ235679A (en) * 1989-10-18 1993-01-27 Int Paper Co Bleaching lignocellulosic pulp using (a) treatment with xylanase and (b) one or more chemical bleaching stages
SE465320B (en) * 1990-01-10 1991-08-26 Korsnaes Ab PREPARATIONS SUBMITTING ENZYMATIC DELIGNIFICATION ACTIVITY, MADE TO MAKE THE SAME AND APPLICATIONS THEREOF
FI88315C (en) * 1990-04-04 1993-04-26 Enso Gutzeit Oy FOERFARANDE FOER BLEKNING AV CELLULOSAMASSA
US5837515A (en) * 1990-05-16 1998-11-17 Alko-Yhtiot Oy Enzyme preparations and methods for their production
GB9018426D0 (en) * 1990-08-22 1990-10-03 Sandoz Ltd Improvements in or relating to novel compounds
NZ239500A (en) * 1990-08-24 1993-08-26 Novo Nordisk As Xylanases obtained from bacillus pumilus and use in a lignocellulosic chemical pulping process
DE4129739A1 (en) * 1990-09-11 1992-03-12 Sandoz Ag Chlorine-free bleaching of paper pulp
FI108800B (en) * 1991-05-07 2002-03-28 Iogen Corp A method and apparatus for using an enzyme in the manufacture and bleaching of pulp
US5498534A (en) * 1992-03-25 1996-03-12 The United States Of America As Represented By The Secretary Of Agriculture Method of removing color from wood pulp using xylanase from streptomyces roseiscleroticus NRRL B-11019
US5369024A (en) * 1992-03-25 1994-11-29 The United States Of America As Represented By The Secretary Of Agriculture Xylanase from streptomyces roseiscleroticus NRRL-11019 for removing color from kraft wood pulps
US5871730A (en) * 1994-07-29 1999-02-16 Universite De Sherbrooke Thermostable xylanase DNA, protein and methods of use
US7816129B2 (en) 1994-07-29 2010-10-19 Ab Enzymes Gmbh Production and secretion of proteins of bacterial origin in filamentous fungi
US5935836A (en) * 1994-07-29 1999-08-10 Rohm Enzyme Finland Oy Actinomadura xylanase sequences and methods of use
US6300114B1 (en) 1994-07-29 2001-10-09 Rohm Enzyme Finland Oy Sequences of xylanase and xylanase expression vectors
CA2435279A1 (en) 2001-01-18 2002-07-25 Iogen Bio-Products Corporation Use of xylanase in pulp bleaching
WO2003074780A1 (en) * 2002-03-06 2003-09-12 Iogen Bio-Products Corporation Xylanase treatment of chemical pulp
CN104963206A (en) * 2014-12-11 2015-10-07 华东理工常熟研究院有限公司 Enzyme modified paper pulp fiber, wood-plastic composite material and preparation method thereof

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NZ216726A (en) * 1985-07-15 1990-08-28 Repligen Corp Use of lignin-degrading enzymes from phanerochaete chrysosporium for treatment of wood pulp and e1 effluent
ZA894239B (en) * 1988-06-08 1990-03-28 Int Paper Co Enzymatic delignification of lignocellulosic material
EP0373107B1 (en) * 1988-11-23 1994-03-23 Sandoz Ag Use of enzymes of Aureobasidium pullulans in pulp bleaching

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8908738A1 *

Also Published As

Publication number Publication date
EP0407421B1 (en) 1996-03-13
JPH03505758A (en) 1991-12-12
FI881192A (en) 1989-09-15
CA1334581C (en) 1995-02-28
BR8907314A (en) 1991-03-19
FI881192A0 (en) 1988-03-14
WO1989008738A1 (en) 1989-09-21
DK175185B1 (en) 2004-06-28
NO903913D0 (en) 1990-09-07
AU626846B2 (en) 1992-08-13
ATE135429T1 (en) 1996-03-15
DK211990D0 (en) 1990-09-04
NO174722B (en) 1994-03-14
NZ228308A (en) 1990-06-26
FI81395B (en) 1990-06-29
NO903913L (en) 1990-09-07
AU3292389A (en) 1989-10-05
DK211990A (en) 1990-11-07
DE68925967D1 (en) 1996-04-18
NO174722C (en) 1994-06-22
DE68925967T2 (en) 1996-09-12

Similar Documents

Publication Publication Date Title
EP0407421A1 (en) Procedure for bleaching cellulose pulp.
Paice et al. Removing hemicellulose from pulps by specific enzymic hydrolysis
RU2126862C1 (en) Method of removing groups of hexenuronic acids from cellulose by heat treatment
EP0483163B1 (en) Environmentally improved process for bleaching lignocellulosic materials
JPS61138793A (en) Reinforcing oxidation extraction method
EP0395792B1 (en) Procedure for the bleaching of pulp
EP0383999B1 (en) Procedure for the bleaching of pulp
CA1277457C (en) Process for bleaching and delignifying cellulose- containing products
GB2248075A (en) Bleaching chemical pulp
EP0513140B2 (en) A process for the bleaching of chemical pulp
EP0408803B1 (en) Procedure for the bleaching of sulphate pulp
JPS6350464B2 (en)
JP3325324B2 (en) Method for delignification of crude cellulose
JPH0931880A (en) Bleaching and modification of chemical pulp
JPH08246368A (en) Enzymatic treatment of chemical pulp
EP0561786B1 (en) Bleaching chemical pulp using chlorine/chlorine dioxide then ozone
US1809312A (en) Process of producing wood pulp of high alpha cellulose content
SU1587095A1 (en) Method of producing bleached pulp for chemical processing
JPH06294087A (en) Bleached kraft pulp
Rue The Chemistry of Bleaching Chemical Wood Pulps
JPH07173785A (en) Method for bleaching chemical pulp with peroxide or ozone
JPH03137285A (en) Method of decarbonizing and bleaching pulp and treating secondary cellulosic fiber
JPH11279968A (en) Bleaching pretreatment of hardwood chemical pulp
CA2062325A1 (en) Process for the bleaching of cellulose in aliphatic monocarbonic acids
JPS6350466B2 (en)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19900903

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

17Q First examination report despatched

Effective date: 19910819

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: GENENCOR INTERNATIONAL EUROPE OY

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19960313

Ref country code: CH

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19960313

REF Corresponds to:

Ref document number: 135429

Country of ref document: AT

Date of ref document: 19960315

Kind code of ref document: T

REF Corresponds to:

Ref document number: 68925967

Country of ref document: DE

Date of ref document: 19960418

ITF It: translation for a ep patent filed

Owner name: STUDIO TORTA SOCIETA' SEMPLICE

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19960429

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: LU

Payment date: 19960501

Year of fee payment: 9

ET Fr: translation filed
PLBQ Unpublished change to opponent data

Free format text: ORIGINAL CODE: EPIDOS OPPO

PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

PLBF Reply of patent proprietor to notice(s) of opposition

Free format text: ORIGINAL CODE: EPIDOS OBSO

26 Opposition filed

Opponent name: PRIMALCO LTD.

Effective date: 19961213

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19970313

NLR1 Nl: opposition has been filed with the epo

Opponent name: PRIMALCO LTD.

PLBF Reply of patent proprietor to notice(s) of opposition

Free format text: ORIGINAL CODE: EPIDOS OBSO

PLBF Reply of patent proprietor to notice(s) of opposition

Free format text: ORIGINAL CODE: EPIDOS OBSO

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19980320

Year of fee payment: 10

RDAH Patent revoked

Free format text: ORIGINAL CODE: EPIDOS REVO

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19990305

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19990309

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 19990311

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19990318

Year of fee payment: 11

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19990329

Year of fee payment: 11

RDAG Patent revoked

Free format text: ORIGINAL CODE: 0009271

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: PATENT REVOKED

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19990517

Year of fee payment: 11

27W Patent revoked

Effective date: 19990208

GBPR Gb: patent revoked under art. 102 of the ep convention designating the uk as contracting state

Free format text: 990208

NLR2 Nl: decision of opposition