WO1998044189A1 - Enzyme aided removal of color from wood pulps - Google Patents
Enzyme aided removal of color from wood pulps Download PDFInfo
- Publication number
- WO1998044189A1 WO1998044189A1 PCT/US1998/006418 US9806418W WO9844189A1 WO 1998044189 A1 WO1998044189 A1 WO 1998044189A1 US 9806418 W US9806418 W US 9806418W WO 9844189 A1 WO9844189 A1 WO 9844189A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pulp
- xylanase
- wood pulp
- cellulase
- wood
- Prior art date
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- 229920001131 Pulp (paper) Polymers 0.000 title claims abstract description 62
- 108090000790 Enzymes Proteins 0.000 title description 15
- 102000004190 Enzymes Human genes 0.000 title description 15
- 101710121765 Endo-1,4-beta-xylanase Proteins 0.000 claims abstract description 191
- 238000000034 method Methods 0.000 claims abstract description 71
- BAVYZALUXZFZLV-UHFFFAOYSA-N Methylamine Chemical compound NC BAVYZALUXZFZLV-UHFFFAOYSA-N 0.000 claims abstract description 66
- 108010059892 Cellulase Proteins 0.000 claims abstract description 47
- 229940106157 cellulase Drugs 0.000 claims abstract description 47
- 241000193385 Geobacillus stearothermophilus Species 0.000 claims abstract description 6
- 229920005610 lignin Polymers 0.000 claims description 51
- 239000011122 softwood Substances 0.000 claims description 29
- 239000002655 kraft paper Substances 0.000 claims description 25
- 239000000203 mixture Substances 0.000 claims description 23
- 150000001412 amines Chemical class 0.000 claims description 21
- 238000011282 treatment Methods 0.000 claims description 20
- 239000011148 porous material Substances 0.000 claims description 18
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- 239000001913 cellulose Substances 0.000 claims description 15
- 239000011121 hardwood Substances 0.000 claims description 13
- 239000000463 material Substances 0.000 claims description 9
- 239000003795 chemical substances by application Substances 0.000 claims description 8
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 7
- 241000228245 Aspergillus niger Species 0.000 claims description 6
- 108010084185 Cellulases Proteins 0.000 claims description 6
- 102000005575 Cellulases Human genes 0.000 claims description 6
- 239000003513 alkali Substances 0.000 claims description 5
- ROSDSFDQCJNGOL-UHFFFAOYSA-N Dimethylamine Chemical compound CNC ROSDSFDQCJNGOL-UHFFFAOYSA-N 0.000 claims description 4
- QUSNBJAOOMFDIB-UHFFFAOYSA-N Ethylamine Chemical compound CCN QUSNBJAOOMFDIB-UHFFFAOYSA-N 0.000 claims description 4
- NAQMVNRVTILPCV-UHFFFAOYSA-N hexane-1,6-diamine Chemical compound NCCCCCCN NAQMVNRVTILPCV-UHFFFAOYSA-N 0.000 claims description 4
- 125000000250 methylamino group Chemical group [H]N(*)C([H])([H])[H] 0.000 claims description 4
- HZAXFHJVJLSVMW-UHFFFAOYSA-N 2-Aminoethan-1-ol Chemical compound NCCO HZAXFHJVJLSVMW-UHFFFAOYSA-N 0.000 claims description 2
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 claims description 2
- AFBPFSWMIHJQDM-UHFFFAOYSA-N N-methylaniline Chemical compound CNC1=CC=CC=C1 AFBPFSWMIHJQDM-UHFFFAOYSA-N 0.000 claims description 2
- AOHJOMMDDJHIJH-UHFFFAOYSA-N propylenediamine Chemical compound CC(N)CN AOHJOMMDDJHIJH-UHFFFAOYSA-N 0.000 claims description 2
- 239000000725 suspension Substances 0.000 claims 1
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- 238000001502 gel electrophoresis Methods 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 34
- 238000004061 bleaching Methods 0.000 description 22
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 15
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 14
- 239000000460 chlorine Substances 0.000 description 14
- 229910052801 chlorine Inorganic materials 0.000 description 14
- 229940088598 enzyme Drugs 0.000 description 14
- 239000012978 lignocellulosic material Substances 0.000 description 14
- 229920001221 xylan Polymers 0.000 description 14
- 150000004823 xylans Chemical class 0.000 description 14
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 229920001817 Agar Polymers 0.000 description 6
- 239000008272 agar Substances 0.000 description 6
- OSVXSBDYLRYLIG-UHFFFAOYSA-N dioxidochlorine(.) Chemical compound O=Cl=O OSVXSBDYLRYLIG-UHFFFAOYSA-N 0.000 description 6
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- 102000004169 proteins and genes Human genes 0.000 description 4
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- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 239000004155 Chlorine dioxide Substances 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- 238000003556 assay Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
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- 239000001301 oxygen Substances 0.000 description 3
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- FXXACINHVKSMDR-UHFFFAOYSA-N acetyl bromide Chemical compound CC(Br)=O FXXACINHVKSMDR-UHFFFAOYSA-N 0.000 description 2
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- -1 methylamine Chemical class 0.000 description 2
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- WDMUXYQIMRDWRC-UHFFFAOYSA-N 2-hydroxy-3,4-dinitrobenzoic acid Chemical compound OC(=O)C1=CC=C([N+]([O-])=O)C([N+]([O-])=O)=C1O WDMUXYQIMRDWRC-UHFFFAOYSA-N 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 241001507865 Aspergillus fischeri Species 0.000 description 1
- 241001277988 Aspergillus sydowii Species 0.000 description 1
- 241000194110 Bacillus sp. (in: Bacteria) Species 0.000 description 1
- 229920003043 Cellulose fiber Polymers 0.000 description 1
- 241001161843 Chandra Species 0.000 description 1
- 241000511343 Chondrostoma nasus Species 0.000 description 1
- 101710101928 Endo-1,4-beta-xylanase 2 Proteins 0.000 description 1
- LLQPHQFNMLZJMP-UHFFFAOYSA-N Fentrazamide Chemical compound N1=NN(C=2C(=CC=CC=2)Cl)C(=O)N1C(=O)N(CC)C1CCCCC1 LLQPHQFNMLZJMP-UHFFFAOYSA-N 0.000 description 1
- 241000223221 Fusarium oxysporum Species 0.000 description 1
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- 229920000297 Rayon Polymers 0.000 description 1
- 240000004808 Saccharomyces cerevisiae Species 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 241000187094 Streptomyces thermoviolaceus Species 0.000 description 1
- 241000223262 Trichoderma longibrachiatum Species 0.000 description 1
- 241000452385 Trichoderma reesei RUT C-30 Species 0.000 description 1
- 229920002522 Wood fibre Polymers 0.000 description 1
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- 229910052710 silicon Inorganic materials 0.000 description 1
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- 239000002002 slurry Substances 0.000 description 1
- 238000002415 sodium dodecyl sulfate polyacrylamide gel electrophoresis Methods 0.000 description 1
- 229910052979 sodium sulfide Inorganic materials 0.000 description 1
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 241000894007 species Species 0.000 description 1
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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
- 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
-
- 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
- D21C9/001—Modification of pulp properties
- D21C9/002—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives
- D21C9/005—Modification of pulp properties by chemical means; preparation of dewatered pulp, e.g. in sheet or bulk form, containing special additives organic compounds
-
- 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
- D21C9/1005—Pretreatment of the pulp, e.g. degassing the pulp
Definitions
- the present invention relates generally to the removal of color from wood pulps using one or more cellulases and/or pore-enlarging agents such as methylamine to alter pulp fiber pore structure to enhance xylanase catalyzed removal of chromophores in processing kraft pulps.
- Paper-making begins by "cooking" chipped pulpwood to produce pulp.
- the cell walls of wood fiber consists of several layers composed primarily of cellulose, hemicellulose and lignin.
- Polymeric constituents of wood are cellulose (40-45 wt% wood), hemicellulose (20-30 wt%), and lignin (20-30 wt%).
- Pulping is a procedure that disintegrates these fibers by mechanical and chemical means. Ultimately, this pulp will be used for papermaking. The objective of pulping is to separate the cellulose fibers and remove as much lignin and hemicellulose as required by the end use, while preserving the fiber strength.
- Kraft pulping is a specific pulping process that uses a wide variety of wood sources to produce quality pulps for manufacture of particularly strong paper.
- Kraft pulping is a highly alkaline method of wood chip digestion characterized by the use of sodium hydroxide and sodium sulfide in the delignification phase.
- the kraft process currently is the most widely used pulping process. Lignin is degraded during the cooking process into chromophoric groups which account for approximately 90% of the dark color associated with unbleached kraft pulp (Casey, J.P., Pulp and Paper: Chemistry and Technology. Vol. 1, 3rd ed., John Wiley & Sons, Inc. New York (1980)).
- Kraft pulp is commonly used for the production of grocery bag stock and linerboard for corrugated containers, but dark pulp must be bleached to eliminate the dark color so bright, high-value paper can be produced.
- the bulk of the colored compounds (“chromophores") created during the pulping process diffuse out of the pulp and are removed in the spent liquors or in the washing stages of the kraft pulping. However, some chromophores remain in the pulp where they are either trapped within the fibers or are chemically bound to the hemicellulosic and cellulosic moieties.
- Xylanase-catalyzed hydrolysis of lignin-carbohydrate complexes was proposed as a reaction mechanism responsible for xylanase delignification of pulp (Yang and Eriksson, Tappi J., 75, 95-101 (1992)).
- Xylanase modification of pulp-surfaces to enable leaching of lignin from pulp was also proposed to explain xylanase delignification of pulp (Buchert, et al. Holzforschung, 47(6), 473-478 (1993)).
- a method of removing chromophores from wood pulp is disclosed, using the combination of a pore-enlarging agent, under conditions not substantially degrading the cellulose, and a xylanase, under conditions wherein the lignan is removed from the cellulose.
- the method includes the steps of first preparing a wood pulp, adjusting the wood pulp to between 1% and 15% consistency (weight %), adjusting the pulp to a pH of between pH 3.0 to 7.0 to maximize cellulase activity, treating the wood pulp with a cellulase to alter the pulp-fiber-pore-structure, adjusting the pulp to between a pH between pH 7.0 and 10.0 to inhibit cellulase activity and maximize xylanase activity, treating the pulp with a xylanase (wherein the xylanase is capable of releasing chromophores from the pulp), and then extracting the pulp to remove chromophores.
- the wood pulp is a kraft pulp
- the cellulase is obtained from Aspergillus niger
- the xylanase is ICI Ecopulp X-200 (ca 20,000 kDa).
- the xylanase is a mixture of xyla- nases in a crude enzyme preparation from a culture of Bacillus stearothermophilus bacteria (ATCC 55696).
- the xylanase is a substantially purified preparation of a xylanase obtained from Bacillus stearothermophilus bacteria (ATCC 55696).
- the extraction is an alkali/hydrogen peroxide extraction.
- the method also includes a method of removing color from a wood pulp which include the steps of first preparing a wood pulp, adjusting the wood pulp to between 1% and 15%> consistency (weight %), adding an organic solvent to the pulp (to between 0.01 wt % and 20 wt%), treating the pulp/solvent mixture with a xylanase (wherein the xylanase is capable of releasing chromophores from the pulp), extracting the pulp to remove chromophores, and then heating the pulp/solvent mixture to remove the organic solvent from the pulp.
- a method of removing color from a wood pulp which include the steps of first preparing a wood pulp, adjusting the wood pulp to between 1% and 15%> consistency (weight %), adding an organic solvent to the pulp (to between 0.01 wt % and 20 wt%), treating the pulp/solvent mixture with a xylanase (wherein the xylanase is capable of releasing chromophores from the pulp),
- the wood pulp is a kraft pulp
- the solvent is methylamine
- the methylamine concentration in the pulp/methylamine mixture is between 1 wt% and 4 wt%
- the xylanase is ICI Ecopulp X-200 (ca 20,000 kDa).
- a method of removing color from a wood pulp wherein the wood pulp contains secondary fiber contains the steps of preparing a wood pulp, treating the wood pulp with xylanase (wherein the xylanase is capable of releasing chromophores from the pulp) and extracting the pulp to remove chromophores.
- the method of removing chromophores from wood pulp containing the steps of preparing a wood pulp, treating the wood pulp with xylanase, wherein the xylanase is capable of releasing chromophores from the pulp. Chromophores are released from the pulp and the pulp is then extracted with an alkaline solution. The pulp is then subjected to bleaching, preferably oxygen bleaching. Another method of removing color from wood pulps begins with the screening of xylanases to obtain a xylanase capable of releasing chromophores from wood pulp. Wood pulp is prepared and treated with the xylanase. The pulp is then extracted to remove the chromophores.
- Xylanases are used to delignify lignocellulosic materials, such as wood pulp, by cleaving the bond between the lignin and the cellulose. While conventional xylanase treatments are able to achieve some level of delignification, conventional xylanase treatments have been unable to produce delignified wood pulp with high brightness levels (ISO brightness numbers exceeding 85%)) without subjecting the pulp to further bleaching steps.
- Pulp is prepared using standard methodologies, from either softwoods, hardwoods, or blends thereof.
- the pulp is prepared as a slurry having a consistency of between one and fifteen percent by weight.
- the pH will be adjusted to the optimum of the enzyme to be used, typically a relatively low pH for the cellulase, and a higher pH for the xylanase.
- a preferred pulp is kraft pulp.
- the extraction is an alkali/hydrogen peroxide extraction.
- lignocellulosic materials are softwood or hardwood pulps, derived from any species.
- other lignocellulosic materials such as bagasse, can be delignified using the methods disclosed herein.
- Preferred wood pulps are softwood pulps.
- the pulp can be virgin pulp, or can already have been subjected to the Kraft process or other preliminary digestion steps. It is preferred that the pulp has already been subjected to Kraft processing before treatment with cellulase or amines and xylanase.
- U.S. Patent No. 5,503,709 to Barton is an example of pulping technology.
- the Kappa number of the pulp will be significantly lowered following treatment with cellulase or amines and xylanase as described herein.
- the lignocellulosic material is dispersed in a solution, preferably an aqueous solution, to produce a dispersion containing between about 1 and 15%) lignocellulosic material by weight of the solution.
- the solution can also contain water-miscible organic solvents, such as ethylene glycol, which increase the boiling point of the solution.
- the lignocellulosic material is treated at a temperature between about 50 and 100 °C. Preferably, the temperature is between 60 and 85 °C, and, more preferably, between 65 and 80 °C.
- the lignocellulosic material is "cooked" for a period of time between about 1 and 24 hours, preferably between about 2 and 8 hours, and, more preferably, between about 3 and 6 hours, although extended times are not harmful.
- the solution is transformed into a black liquor which contains, in part, lignin that has been removed from the lignocellulosic material.
- the black liquor can be separated from the pulp, for example, via centrifugation and washing. If desired, the low molecular weight amines can be removed from the liquor, for example, by distillation, and reused in the next batch of lignocellulosic material to be delignified.
- the lignin can be used, for example, as a resin binder, a wood rehardening agent, or a glue.
- cellulases which have optimal activity at different pHs, typically obtained from bacterial or fungal sources, can be used.
- Cellulases are typically selected based on their pH optimum.
- a particularly preferred cellulase is obtained from Aspergillus niger, which is used at low pH and inactivated by elevation of the pH. See articles reporting various cellulases, such as Trichoderma reesei cellulase in the bleaching of kraft pulp, by Buchert et al., Applied Microbiology and Biotechnology 40(6): 941-945 (1994); "Effect of Alkali Pretreatment on Degradation of some Cellulosic Wastes by Aspergillus-sydowii", Ghareib , et al.
- the wood pulp is a kraft pulp
- the cellulase is obtained from Aspergillus niger
- the xylanase is ICI Ecopulp X-200 (ca 20,000 kDa).
- xylanase treatments can be significantly enhanced using the methods disclosed herein by using a low molecular weight amine prior to, or simultaneously with, xylanase treatment. It is believed that the amines expand the pore size in the pulp and allow the xylanase to effectively penetrate the pulp and have access to more of the lignin-cellulose bonds, relative to when xylanase alone is used.
- Lignocellulosic materials are delignified with low molecular weight amines and xylanases by contacting the materials with an effective amount of the amines and xylanases, sequentially or simultaneously, at an effective temperature and pressure, for an effective amount of time, to cleave a significant percentage of the lignin-cellulose bonds.
- the degree of delignification can be significantly increased when pulp is treated with xylanase and a low molecular weight amine such as methylamine, simultaneously or sequentially, relative to when xylanase alone is used.
- Any low molecular weight amine can be used which is able to increase the pore size of the pulp to be treated, does not reduce the activity of the xylanase by more than 50%> in the solution in which it is used, and which can be readily removed from the pulp by extraction in an aqueous solution.
- the amines also assist in cleaving the lignin-cellulose bonds present in the pulp.
- Suitable amines include methylamine, monoethanolamine, dimethylamine, ethylenediamine, propylene diamine, hexamethylene diamine, methylaniline, ethylamine and mixtures thereof.
- the preferred amine is methylamine.
- the concentration of low molecular weight amines in the dispersion of lignocellulosic material to be treated is between about 1 and 10%> by volume of the solution.
- concentration is between about 1 and 4 percent by volume, although concentrations as high as 10%> by volume can be used.
- lignocellulosic material is first delignified with a low molecular weight amine, such as methylamine, the lignin-containing solution is removed, and then the material is delignified with xylanase.
- the xylanase is a mixture of xylanases in a crude enzyme preparation from a culture of Bacillus stearothermophilus bacteria (ATCC 55696).
- the xylanase is a substantially purified preparation of a xylanase obtained from Bacillus stearothermophilus bacteria (ATCC 55696).
- Xylanase delignification of pulp is a function of xylanase molecular size and pulp pore structure.
- Xylanase molecular size can limit pulp delignification if pulp pore structure selectively admits xylanases based on molecular size into pulp pores. This relationship was demonstrated by the examples. The examples demonstrate that xylanase molecular size and pulp pore structure determine the amount of lignin that xylanase can remove from pulp. Using softwood pulp, xylanases with molecular weights of 20,000 Da, 39,000 Da, and 67,000 Da removed 48%, 39%, and 30%) of lignin respectively.
- a method of removing chromophores from wood pulp is disclosed, using the combination of a pore-enlarging agent, under conditions not substantially degrading the cellulose, and a xylanase, under conditions wherein the lignan is removed from the cellulose.
- the method includes the steps of first preparing a wood pulp, adjusting the wood pulp to between 1%> and 15%) consistency (weight %>), adjusting the pulp to a pH of between pH 3.0 to 7.0 to maximize cellulase activity, treating the wood pulp with a cellulase to alter the pulp-fiber-pore-structure, adjusting the pulp to between a pH between pH 7.0 and 10.0 to inhibit cellulase activity and maximize xylanase activity, treating the pulp with a xylanase (wherein the xylanase is capable of releasing chromophores from the pulp), and then extracting the pulp to remove chromophores.
- the wood pulp is a kraft pulp
- the cellulase is obtained from Aspergillus niger
- the xylanase is ICI Ecopulp X-200 (ca 20,000 kDa).
- the color is removed from a wood pulp using the steps of first preparing a wood pulp, adjusting the wood pulp to between 1% and 15%) consistency (weight %), adding an organic solvent to the pulp (to between 0.01 wt % and 20 wt%>), treating the pulp/solvent mixture with a xylanase (wherein the xylanase is capable of releasing chromophores from the pulp), extracting the pulp to remove chromophores, and then heating the pulp/solvent mixture to remove the organic solvent from the pulp.
- the wood pulp is a kraft pulp
- the solvent is methylamine
- the methylamine concentration in the pulp/ methylamine mixture is between 1 wt% and 4 wt%>
- the xylanase is ICI Ecopulp X-200 (ca 20,000 kDa).
- Pre-treatments Color can be removed from a wood pulp wherein the wood pulp contains secondary fiber. This method contains the steps of preparing a wood pulp, treating the wood pulp with xylanase (wherein the xylanase is capable of releasing chromophores from the pulp) and extracting the pulp to remove chromophores.
- the method of removing chromophores from wood pulp containing the steps of preparing a wood pulp, treating the wood pulp with xylanase, wherein the xylanase is capable of releasing chromophores from the pulp. Chromophores are released from the pulp and the pulp is then extracted with an alkaline solution. The pulp is then subjected to bleaching, preferably oxygen bleaching. Reduction in %> Lignin
- the amount of lignin remaining after treatment can be analyzed using the method described in Llyama and Wallis, Wood Sci. Tech. , 22(3):271-272 (1988).
- Example 1 A priori estimation of xylanase delignification Methods and Materials The relationship between xylanase-accessible-lignin moieties and xylanase-molecular-size was assumed to map identically to the log-normal distribution of cumulative-pore-volume versus pore-size for spruce kraft pulp (Allan, et. al, 1991; Scallan, 1978; Stone and Scallan, 1968). Xylanase molecular size was assumed to be twice the radius of gyration obtained from the general relationship between protein molecular weight and radius of gyration (Tyn and Gusek, 1990).
- each pulp mixture was filtered, and washed with 100 ml each of deionized (D.I.) water, 0.5 N NaOH, D.I. water, 0.5 N HCl, and D.I. water. Pulp was then assayed for residual lignin (Iiyama and Wallis, Wood Sci. Technol, 22(3), 271-272 (1988)). Control pulp samples were treated identically to the experimental samples except no xylanase was added.
- D.I. deionized
- Xylanase from the PDB had maximum dimension of 40 Angstroms. Based on this result, estimates of the maximum dimension values for ICI, UGA, and Ciba xylanases were 41 Angstroms, 48 Angstroms, and 56 Angstroms, respectively. Using these maximum dimension values and the cumulative pore volume distribution , estimates for maximum lignin removal were 50%), 40%, and 32%) of original pulp lignin.
- Lignin removed by ICI, UGA and Ciba was 48%, 39%, and 30%> respectively. Fitting these data to the log-normal distribution of cumulative pore volume versus pore-size yielded a median pore size of 40.5 Angstroms, with standard deviation of 2.1 Angstroms (Allan et. al, 1991). Lignin removal from control pulp samples was non-detectable.
- Ciba xylanases was 67.7%) and 40.4%) respectively. These data were fitted to the log-normal distribution of cumulative pore volume versus pore-size, which yielded a median pore size of 66.7 Angstroms (standard deviation of 2.1 Angstroms) for cellulase-treated pulp.
- softwood pulp had a Kappa number of 26.7 and a viscosity of 22.72 cp prior to any enzyme treatment. Pulp brightness, viscosity, and Kappa number after the bleaching sequence were 85.5%o, 9.12 cp, and 19.8, respectively.
- Softwood pulp treated with enzyme before bleaching required 31 ) less chlorine than the control.
- Hardwood pulp had a Kappa number of 12.7 and viscosity of 27.5 cp prior to any enzyme treatment. Pulp brightness, viscosity, and Kappa number after the bleaching sequence were 89.0%>, 13.75 cp, and 6.4, respectively. Hardwood pulp treated with enzyme before bleaching required 41.8% less chlorine than the control.
- lignin removal from controls pulp treated with no enzyme, and, pulp treated with cellulase and no xylanase, was non- detectable.
- xylan media 100 ml
- Seven groups with three flasks each were adjusted to pH 5, 6, 7, 8, 9, 10, and 11 respectively, and inoculated with ten ml of stock culture; three flasks were sterile controls.
- Each group of flasks were separately incubated in a shaker (120 RPM) for 30 hours at 40°C, 60°C, 70°C, and 80°C respectively.
- Media from each flask was centrifuged (Dupont Sorvall RC 28S, Newton, CT, USA) at 9000 x g for 15 minutes. The pellet from each culture was dried as before. Net growth for each flask was computed as before.
- DMS dinitrosalicylic acid
- each pulp mixture was filtered, and washed with 100 ml each of D.I. water, 0.5 N NaOH, D.I. water, 0.5 N HCl, and D.I. water. Pulp was then assayed for residual lignin (Iyama and Wallis, 1988). Control pulp samples were treated identically to the experimental samples except no xylanase was added.
- Example 5 Methylamine use in pulp delignification
- Methylamine effect on xylanase Xylanase was assayed in buffer of 0% and 10%) methylamine respectively.
- Methylamine effect on xylanase delignification Xylanase, pulp, and methylamine were combined to yield a final concentration of 0%, 4%> or 10%) methylamine in a final volume of 100 ml and incubated for 2 hours as indicated in Table 1.
- the experiment was repeated using a 10%) concentration of methylamine. Using methylamine alone, the lignin content was reduced to about 68%) of the original value. Using 1 mL of the xylanase solution, the remaining lignin was about 65%) of the original value. When the amount of xylanase was doubled, the amount of residual lignin was reduced to about 47%). However, when the treatment included 10%> methylamine and 2 mL of a xylanase solution, the lignin content was reduced to about 46%.
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CA002285244A CA2285244A1 (en) | 1997-03-31 | 1998-03-31 | Enzyme aided removal of color from wood pulps |
AU67921/98A AU6792198A (en) | 1997-03-31 | 1998-03-31 | Enzyme aided removal of color from wood pulps |
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US82915397A | 1997-03-31 | 1997-03-31 | |
US829,153 | 1997-03-31 |
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Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2001064830A1 (en) * | 2000-03-03 | 2001-09-07 | Ets. Robert Stiernon S.A. | Methods for producing oenological tannins and enzymatic composition |
US10519597B2 (en) | 2009-10-16 | 2019-12-31 | Suzano S.A. | Process for producing differentiated cellulose fibers comprising an enzymatic treatment in association with an acid step |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1991002839A1 (en) * | 1989-08-25 | 1991-03-07 | Novo Nordisk A/S | Process for treatment of lignocellulosic pulp |
US5503709A (en) * | 1994-07-27 | 1996-04-02 | Burton; Steven W. | Environmentally improved process for preparing recycled lignocellulosic materials for bleaching |
WO1996018770A2 (en) * | 1994-12-16 | 1996-06-20 | Lignozym Gmbh | Multicomponent system for modifying, decomposing or bleaching lignin, lignin-containing materials or similar substances and method of using this system |
WO1997036041A1 (en) * | 1996-03-27 | 1997-10-02 | Consortium für elektrochemische Industrie GmbH | Multicomponent system for changing, reducing or bleaching lignin, lignin-containing materials or similar substances as well as processes for its application |
US5725732A (en) * | 1994-11-18 | 1998-03-10 | P. H. Glatfelter Company | Process for treating hardwood pulp with an enzyme mixture to reduce vessel element picking |
-
1998
- 1998-03-31 CA CA002285244A patent/CA2285244A1/en not_active Abandoned
- 1998-03-31 WO PCT/US1998/006418 patent/WO1998044189A1/en active Application Filing
- 1998-03-31 AU AU67921/98A patent/AU6792198A/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1991002839A1 (en) * | 1989-08-25 | 1991-03-07 | Novo Nordisk A/S | Process for treatment of lignocellulosic pulp |
US5503709A (en) * | 1994-07-27 | 1996-04-02 | Burton; Steven W. | Environmentally improved process for preparing recycled lignocellulosic materials for bleaching |
US5725732A (en) * | 1994-11-18 | 1998-03-10 | P. H. Glatfelter Company | Process for treating hardwood pulp with an enzyme mixture to reduce vessel element picking |
WO1996018770A2 (en) * | 1994-12-16 | 1996-06-20 | Lignozym Gmbh | Multicomponent system for modifying, decomposing or bleaching lignin, lignin-containing materials or similar substances and method of using this system |
WO1997036041A1 (en) * | 1996-03-27 | 1997-10-02 | Consortium für elektrochemische Industrie GmbH | Multicomponent system for changing, reducing or bleaching lignin, lignin-containing materials or similar substances as well as processes for its application |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2001064830A1 (en) * | 2000-03-03 | 2001-09-07 | Ets. Robert Stiernon S.A. | Methods for producing oenological tannins and enzymatic composition |
AU783972B2 (en) * | 2000-03-03 | 2006-01-12 | Ets Robert Stiernon S.A. | Methods for producing oenological tannins and enzymatic composition |
US7396549B2 (en) | 2000-03-03 | 2008-07-08 | Ets. Robert Stiernon, S.A. | Method for producing oenological tannins and enzymatic composition |
US10519597B2 (en) | 2009-10-16 | 2019-12-31 | Suzano S.A. | Process for producing differentiated cellulose fibers comprising an enzymatic treatment in association with an acid step |
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AU6792198A (en) | 1998-10-22 |
CA2285244A1 (en) | 1998-10-08 |
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