EP0408803B1 - Procedure for the bleaching of sulphate pulp - Google Patents
Procedure for the bleaching of sulphate pulp Download PDFInfo
- Publication number
- EP0408803B1 EP0408803B1 EP89117234A EP89117234A EP0408803B1 EP 0408803 B1 EP0408803 B1 EP 0408803B1 EP 89117234 A EP89117234 A EP 89117234A EP 89117234 A EP89117234 A EP 89117234A EP 0408803 B1 EP0408803 B1 EP 0408803B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pulp
- bleaching
- procedure
- chlorine
- enzyme
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000004061 bleaching Methods 0.000 title claims abstract description 25
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 title claims description 8
- 229910021653 sulphate ion Inorganic materials 0.000 title claims description 8
- 108090000790 Enzymes Proteins 0.000 claims abstract description 28
- 102000004190 Enzymes Human genes 0.000 claims abstract description 28
- 239000000126 substance Substances 0.000 claims abstract description 21
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 claims abstract description 18
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000000460 chlorine Substances 0.000 claims abstract description 12
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 12
- 239000004155 Chlorine dioxide Substances 0.000 claims abstract description 9
- 235000019398 chlorine dioxide Nutrition 0.000 claims abstract description 9
- 230000003647 oxidation Effects 0.000 claims abstract description 7
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 7
- 241000233866 Fungi Species 0.000 claims abstract description 6
- 239000000203 mixture Substances 0.000 claims abstract description 4
- 230000033116 oxidation-reduction process Effects 0.000 claims abstract description 4
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims abstract description 3
- 108010029541 Laccase Proteins 0.000 claims description 9
- 102000003425 Tyrosinase Human genes 0.000 claims description 4
- 108060008724 Tyrosinase Proteins 0.000 claims description 4
- 239000003513 alkali Substances 0.000 claims description 4
- 238000006911 enzymatic reaction Methods 0.000 claims description 2
- 238000004076 pulp bleaching Methods 0.000 claims description 2
- 241000218680 Pinus banksiana Species 0.000 claims 1
- 239000011122 softwood Substances 0.000 claims 1
- 239000007844 bleaching agent Substances 0.000 abstract description 9
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 7
- 239000001301 oxygen Substances 0.000 abstract description 7
- 229910052760 oxygen Inorganic materials 0.000 abstract description 7
- VGVRPFIJEJYOFN-UHFFFAOYSA-N 2,3,4,6-tetrachlorophenol Chemical class OC1=C(Cl)C=C(Cl)C(Cl)=C1Cl VGVRPFIJEJYOFN-UHFFFAOYSA-N 0.000 abstract description 2
- 229940088598 enzyme Drugs 0.000 abstract 2
- 102100026189 Beta-galactosidase Human genes 0.000 abstract 1
- 108010059881 Lactase Proteins 0.000 abstract 1
- 108010005774 beta-Galactosidase Proteins 0.000 abstract 1
- 229940116108 lactase Drugs 0.000 abstract 1
- 229920005610 lignin Polymers 0.000 description 10
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 239000007857 degradation product Substances 0.000 description 3
- 150000004045 organic chlorine compounds Chemical class 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 239000010902 straw Substances 0.000 description 3
- 229920002488 Hemicellulose Polymers 0.000 description 2
- 108700020962 Peroxidase Proteins 0.000 description 2
- 102000003992 Peroxidases Human genes 0.000 description 2
- 235000008331 Pinus X rigitaeda Nutrition 0.000 description 2
- 235000011613 Pinus brutia Nutrition 0.000 description 2
- 241000018646 Pinus brutia Species 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 108010002430 hemicellulase Proteins 0.000 description 2
- 150000004965 peroxy acids Chemical class 0.000 description 2
- 231100000331 toxic Toxicity 0.000 description 2
- 230000002588 toxic effect Effects 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 239000002023 wood Substances 0.000 description 2
- 235000018185 Betula X alpestris Nutrition 0.000 description 1
- 235000018212 Betula X uliginosa Nutrition 0.000 description 1
- 108090000854 Oxidoreductases Proteins 0.000 description 1
- 102000004316 Oxidoreductases Human genes 0.000 description 1
- 241000222357 Trametes hirsuta Species 0.000 description 1
- 238000005660 chlorination reaction Methods 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 108010062085 ligninase Proteins 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000004537 pulping Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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
- D21C9/1057—Multistage, with compounds cited in more than one sub-group D21C9/10, D21C9/12, D21C9/16
-
- 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
- D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
- D21C5/005—Treatment of cellulose-containing material with microorganisms or enzymes
Definitions
- the present invention relates to a procedure for the bleaching of pulp, in which procedure an oxidating bleaching chemical containing chlorine is used.
- Especially pulp obtained from a sulphate pulping process is of brown colour, which is mainly due to the lignin remaining in the pulp.
- Lignin is removed from the pulp by bleaching, which is generally a process consisting of several stages. During this process, the pulp is treated alternately with oxidizing, lignin-degrading chemicals and chemicals dissolving the degradation products. Oxidizing agents commonly used are chlorine-containing chemicals and oxygen, whereas alkali solutions are used for eliminating the degradation products.
- the spent bleach liquors causing the worst environmental pollution load are produced in the washing stages following the first chlorination and the first alkali treatment in the bleaching process.
- various methods have been employed, including the use of chlorine dioxide instead of chlorine gas, the use of oxygen as an oxidating chemical in the first bleaching stage, and biological purification of the spent bleach liquor.
- these methods have not yielded completely satisfactory results.
- the amounts of chlorophenols and other toxic-chlorine compounds in the spent bleach liquor have been significantly reduced by using chlorine dioxide and employing oxygen bleaching, it has not been possible to achieve a sufficient reduction in the chemical oxygen demand values of the effluents. Therefore, the methods referred to have required the employment of efficient biological purification.
- DE-A-3 636 208 discloses a method based on the treatment of natural or mechanically modified pulp raw material. The process is described with one example in which straw is treated with enzymes in order to dissolve the lignin. It has to be noted that there are significant differences of the structure of straw lignin and wood lignin (Wei He Diesheng Tai and Stephen Y. Lin, 1991). In addition, the known process calls for a pretreatment, whereby straw was pretreated with 1-2 % NaOH for 24-28 hrs, and was grinded before addition of enzyme. Such pretreatment is technically difficult, and not suitable for removing of the wood lignin.
- the object of the present invention is to achieve a sulphate pulp bleaching procedure that enables the toxic content and chemical oxygen demand of the spent bleach liquor to be reduced so as to reduce the need for purification of the liquor. This object is achieved by the characterizing part of claim 1.
- a treatment with a suitable redox enzyme reduces the amount of chlorine chemicals required for bleaching, thereby also reducing the amounts of organic chlorine compounds left in the spent bleach liquor.
- the redox potential of the enzymatic reaction should be below 400 mV, preferably below 250 mV.
- Suitable redox enzymes are phenoloxidases, such as the laccase produced by the white-rot fungus.
- the bleaching of pulp by the procedure of the invention can be performed in the conventional manner by employing alternate oxidation and alkali stages and washing the pulp after each of these stages to remove the bleaching chemicals and degradation products.
- the enzyme treatment as taught by the invention is preferably carried out in a temperature range of 10-90 °C, the most suitable range being 40-80 °C, with pH values in the range 3.0-10.0, preferably 4.0-8.0.
- the enzyme used is the lignin-modifying oxidation-reduction enzyme, laccase, as mentioned above.
- the invention also concerns the use of a lignin-modifying enzyme, e.g. the laccase produced by the white-rot fungus, in the bleaching of sulphate pulp using an oxidating bleaching chemical containing chlorine.
- a lignin-modifying enzyme e.g. the laccase produced by the white-rot fungus
- a diluted enzyme mixture of laccase produced by the Trametes hirsuta white-rot fungus was added to 220 g of dry matter obtained from pine sulphate pulp (with a dry matter content of 30%) so that a mixture with a consistency of 10% and a laccase activity of 60 U/kg of pulp dry matter was obtained.
- the temperature in the enzyme treatment was 55 °C and the duration of treatment 2 h. After the enzyme treatment the pulp wax filtered in a Buchner funnel and the pulp cake obtained was washed with ion-exchange-treated water so that a wash ratio of 20 was obtained.
- both the pulp quantity which had undergone enzyme treatment and the reference portion were bleached by a process consisting of five successive stages of oxidation and bleaching.
- the chemicals used were chlorine (90%) and chlorine dioxide (10%), in the second stage sodium hydroxide, in the third stage chlorine dioxide, in the fourth stage sodium hydroxide and in the fifth stage chlorine dioxide.
- the experiment shows that by using a lignin-modifying enzyme, i.e. laccase, a substantial reduction in the amount of chlorine has been achieved.
- a lignin-modifying enzyme i.e. laccase
Abstract
The invention concerns a procedure for the bleaching of pulp, in which procedure an oxidating bleaching chemical containing chlorine is used. The essential feature of the invention is that the pulp is treated, either in conjunction with or before oxidation, with a lignin-modifying oxidation-reduction enzyme, such as the lactase produced by the white-rot fungus. The oxidating bleaching chemical used in the procedure may be chlorine dioxide or a mixture of chlorine dioxide and chlorine gas. The use of said enzyme reduces the amount of chlorophenols and other forms of organically bound chlorine in the spent bleach liquor, simultaneously lowering its chemical oxygen demand.
Description
- The present invention relates to a procedure for the bleaching of pulp, in which procedure an oxidating bleaching chemical containing chlorine is used.
- Especially pulp obtained from a sulphate pulping process is of brown colour, which is mainly due to the lignin remaining in the pulp. Lignin is removed from the pulp by bleaching, which is generally a process consisting of several stages. During this process, the pulp is treated alternately with oxidizing, lignin-degrading chemicals and chemicals dissolving the degradation products. Oxidizing agents commonly used are chlorine-containing chemicals and oxygen, whereas alkali solutions are used for eliminating the degradation products.
- In the reactions occurring in bleaching using chlorine-containing chemicals, lignin is converted into organic chlorine compounds, which remain in the spent bleach liquor. Spent bleach liquors are a problem in regard of environmental protection because of the possible toxic nature of the organic chlorine compounds contained in the liquors. Moreover, the chemical oxygen demand in spent bleach liquors reaches detrimental levels.
- The spent bleach liquors causing the worst environmental pollution load are produced in the washing stages following the first chlorination and the first alkali treatment in the bleaching process. To reduce the pollution load, various methods have been employed, including the use of chlorine dioxide instead of chlorine gas, the use of oxygen as an oxidating chemical in the first bleaching stage, and biological purification of the spent bleach liquor. However, these methods have not yielded completely satisfactory results. Although the amounts of chlorophenols and other toxic-chlorine compounds in the spent bleach liquor have been significantly reduced by using chlorine dioxide and employing oxygen bleaching, it has not been possible to achieve a sufficient reduction in the chemical oxygen demand values of the effluents. Therefore, the methods referred to have required the employment of efficient biological purification.
- DE-A-3 636 208 (see also WO-A-8 803 190) discloses a method based on the treatment of natural or mechanically modified pulp raw material. The process is described with one example in which straw is treated with enzymes in order to dissolve the lignin. It has to be noted that there are significant differences of the structure of straw lignin and wood lignin (Wei He Diesheng Tai and Stephen Y. Lin, 1991). In addition, the known process calls for a pretreatment, whereby straw was pretreated with 1-2 % NaOH for 24-28 hrs, and was grinded before addition of enzyme. Such pretreatment is technically difficult, and not suitable for removing of the wood lignin.
- Int. Cont. Biotechnol. Pulp & PaperInd. (1986), 67-69, concerns the enzyme treatment of a cellulose mass concentrating mainly on the use of the hemicellulases. By the use of hemicellulases chemical savings in the chlorine bleaching have been obtained, but the use of oxidases and ligninases is based on completely different reaction mechanisms which are difficult to rule (Lehninger). In the publication it is mentioned that the use of peroxidases was tested with birch and pine peroxyacid pulps. The pulps produced by the peroxyacid treatment differ substantially from the conventionally produced pulps. Additionally, the enzymed tested were peroxidases or ligninasees. In the publication it is also mentioned that the lignin content of the pulp dit not change substantially as a result of the treatment. This shows how difficult it was to reduce the lignin content with enzymes.
- Tappi, Vol 67, 1984, 31-33, the possibilities of "lignin-degrading enzymes" is discussed in general terms. The publication does not contain any concrete knowledge of the subject to be discussed.
- The object of the present invention is to achieve a sulphate pulp bleaching procedure that enables the toxic content and chemical oxygen demand of the spent bleach liquor to be reduced so as to reduce the need for purification of the liquor. This object is achieved by the characterizing part of claim 1.
- It has been observed in earlier investigations that by using enzymes degrading hemicellulose it is possible to separate lignin and/or hemicellulose from cellulose and thus make the pulp more easily bleachable in the subsequent bleaching stages. This effect has not been observed before in conjunction with the use of lignin-degrading enzymes.
- According to the invention, it has now been observed that a treatment with a suitable redox enzyme reduces the amount of chlorine chemicals required for bleaching, thereby also reducing the amounts of organic chlorine compounds left in the spent bleach liquor.
- According to the invention, the redox potential of the enzymatic reaction should be below 400 mV, preferably below 250 mV. Suitable redox enzymes are phenoloxidases, such as the laccase produced by the white-rot fungus.
- Except for the enzyme treatment, the bleaching of pulp by the procedure of the invention can be performed in the conventional manner by employing alternate oxidation and alkali stages and washing the pulp after each of these stages to remove the bleaching chemicals and degradation products.
- The enzyme treatment as taught by the invention is preferably carried out in a temperature range of 10-90 °C, the most suitable range being 40-80 °C, with pH values in the range 3.0-10.0, preferably 4.0-8.0. The enzyme used is the lignin-modifying oxidation-reduction enzyme, laccase, as mentioned above.
- The invention also concerns the use of a lignin-modifying enzyme, e.g. the laccase produced by the white-rot fungus, in the bleaching of sulphate pulp using an oxidating bleaching chemical containing chlorine.
- In the following, the invention is described in greater detail by the aid of examples of embodiments based on laboratory experiments.
- A diluted enzyme mixture of laccase produced by the Trametes hirsuta white-rot fungus was added to 220 g of dry matter obtained from pine sulphate pulp (with a dry matter content of 30%) so that a mixture with a consistency of 10% and a laccase activity of 60 U/kg of pulp dry matter was obtained. The temperature in the enzyme treatment was 55 °C and the duration of treatment 2 h. After the enzyme treatment the pulp wax filtered in a Buchner funnel and the pulp cake obtained was washed with ion-exchange-treated water so that a wash ratio of 20 was obtained.
- For reference, a corresponding portion of pulp was treated in the same way except that no enzyme was added.
- Next, both the pulp quantity which had undergone enzyme treatment and the reference portion were bleached by a process consisting of five successive stages of oxidation and bleaching. In the first stage, the chemicals used were chlorine (90%) and chlorine dioxide (10%), in the second stage sodium hydroxide, in the third stage chlorine dioxide, in the fourth stage sodium hydroxide and in the fifth stage chlorine dioxide.
- The consumption of bleaching chemicals and the analysis results representing the quality of the bleached pulp are presented in Table 1.
- The experiment shows that by using a lignin-modifying enzyme, i.e. laccase, a substantial reduction in the amount of chlorine has been achieved.
Claims (7)
- Procedure for the bleaching of sulphate pulp, said procedure using an oxidating bleaching chemical containing chlorine, characterized in that, before oxidation, the pulp is subjected to an enzyme treatment in which a lignin-modifying oxidation-reduction enzyme is used, and in that the enzyme used is a lignin-modifying phenoloxidase, such as the laccase produced by the white-rot fungus.
- Procedure according to claim 1, characterized in that the redox potential of the enzymatic reaction is below 400 mV, preferably below 250 mV.
- Procedure according to any one of the preceding claims, characterized in that the pulp is treated with a phenoloxidase, e.g. laccase, and washed before the first oxidation phase.
- Procedure according to any one of the preceding claims, characterized in that the bleaching chemical used in the oxidation phases is chlorine dioxide or a mixture of chlorine dioxide and chlorine gas, and that between the oxidation phases the pulp is treated with an alkali.
- Procedure according to any one of the preceding claims, characterized in that the enzyme treatment is carried out in a temperature range of 10-90 °C, preferably 40-80 °C, with pH values in the range 3.0-10.0, preferably 4.0-8.0.
- Procedure according to any one of the preceding claims, characterized in that the procedure is used for the bleaching of softwood pulp, e.g. pine sulphate pulp.
- Use of a lignin-modifying oxidation-reduction enzyme wherein the enzyme used is a phenoloxidase, e.g. the laccase produced by the white-rot fungus in a sulphate pulp bleaching process using an oxidating bleaching chemical containing chlorine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT89117234T ATE100157T1 (en) | 1989-07-10 | 1989-09-18 | METHOD OF BLEACHING SULFATE PULP. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI893338A FI88316C (en) | 1989-07-10 | 1989-07-10 | Process for bleaching cellulose pulp |
| FI893338 | 1989-07-10 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0408803A1 EP0408803A1 (en) | 1991-01-23 |
| EP0408803B1 true EP0408803B1 (en) | 1994-01-12 |
Family
ID=8528744
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP89117234A Expired - Lifetime EP0408803B1 (en) | 1989-07-10 | 1989-09-18 | Procedure for the bleaching of sulphate pulp |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0408803B1 (en) |
| JP (1) | JP2831048B2 (en) |
| AT (1) | ATE100157T1 (en) |
| CA (1) | CA1335184C (en) |
| DE (1) | DE68912322D1 (en) |
| ES (1) | ES2061857T3 (en) |
| FI (1) | FI88316C (en) |
| NO (1) | NO175105C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7183090B2 (en) | 2000-05-23 | 2007-02-27 | Valtion Teknillinen Tutkimuskeskus | Laccase enzyme and the gene encoding the enzyme |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| 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 |
| 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 |
| CA2115881C (en) * | 1993-02-25 | 2000-05-23 | Michael G. Paice | Non-chlorine bleaching of kraft pulp |
| US5480801A (en) * | 1993-09-17 | 1996-01-02 | Novo Nordisk A/S | Purified PH neutral Rhizoctonia laccases and nucleic acids encoding same |
| US6824646B2 (en) | 1999-03-23 | 2004-11-30 | Oji Paper Co., Ltd. | Process for oxygen bleaching and enzyme treating lignocellulosic pulp with liquid treatment and recovery |
| US6942754B2 (en) | 1999-03-23 | 2005-09-13 | Oji Paper Co., Ltd. | Process for producing xylooligosaccharide from lignocellulose pulp |
| ES2221529B1 (en) * | 2002-07-10 | 2005-11-01 | Instituto Nacional De Investigacion Y Tecnologia Agraria Y Alimentaria (Inia) | PROCEDURE FOR THE DESLIGNIFICATION OF CELLULOSE PASTA. |
| CN109537343A (en) * | 2018-11-29 | 2019-03-29 | 崔雪柯 | A kind of paper pulp gas-water separation technique |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3636208A1 (en) * | 1986-10-24 | 1988-05-05 | Call Hans Peter | METHOD FOR DELIGNIFYING AND WHICH BLEACHING LIGNICELLULOSE-CONTAINING OR LIGNINAL MATERIAL OR LIGNIN BY ENZYMATIC TREATMENT |
-
1989
- 1989-07-10 FI FI893338A patent/FI88316C/en active IP Right Grant
- 1989-09-18 JP JP1241665A patent/JP2831048B2/en not_active Expired - Lifetime
- 1989-09-18 DE DE89117234T patent/DE68912322D1/en not_active Expired - Lifetime
- 1989-09-18 EP EP89117234A patent/EP0408803B1/en not_active Expired - Lifetime
- 1989-09-18 CA CA000611772A patent/CA1335184C/en not_active Expired - Fee Related
- 1989-09-18 AT AT89117234T patent/ATE100157T1/en not_active IP Right Cessation
- 1989-09-18 ES ES89117234T patent/ES2061857T3/en not_active Expired - Lifetime
- 1989-09-18 NO NO893715A patent/NO175105C/en not_active IP Right Cessation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7183090B2 (en) | 2000-05-23 | 2007-02-27 | Valtion Teknillinen Tutkimuskeskus | Laccase enzyme and the gene encoding the enzyme |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2831048B2 (en) | 1998-12-02 |
| JPH03130485A (en) | 1991-06-04 |
| ES2061857T3 (en) | 1994-12-16 |
| FI88316B (en) | 1993-01-15 |
| NO893715L (en) | 1991-01-11 |
| CA1335184C (en) | 1995-04-11 |
| FI88316C (en) | 1993-04-26 |
| FI893338A (en) | 1991-01-11 |
| NO175105C (en) | 1994-08-31 |
| NO893715D0 (en) | 1989-09-18 |
| NO175105B (en) | 1994-05-24 |
| DE68912322D1 (en) | 1994-02-24 |
| EP0408803A1 (en) | 1991-01-23 |
| FI893338A0 (en) | 1989-07-10 |
| ATE100157T1 (en) | 1994-01-15 |
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