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F S Archibald - One of the best experts on this subject based on the ideXlab platform.
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kraft Pulp Bleaching and delignification by trametes versicolor
Journal of Biotechnology, 1997Co-Authors: F S Archibald, M G Paice, R Bourbonnais, L Jurasek, I D ReidAbstract:In 1989 we reported that the white-rot basidiomycete fungus Trametes versicolor could delignify and substantially brighten unbleached kraft Pulps. Since that time, considerable effort has been dedicated to understanding the biological mechanisms of this efficient delignification system in the hope that part or all of the system can be applied industrially. Early work indicated that all components necessary for extensive kraft Pulp Bleaching and delignification are secreted by the fungus, but that one or more of these components must be constantly replaced or renewed. T. versicolor can bleach O2-delignified and extended-cooking Pulps as well as conventional hardwood and softwood kraft Pulps. The fungus demethylates and solubilizes the residual lignin in the Pulps, seemingly without depolymerization. Enzyme families secreted by T. versicolor which may be involved in delignification include lignin peroxidases (LiP), manganese peroxidases (MnP), laccases, and cellobiose dehydrogenases (CDH). Each of these families has been investigated for its interactions with kraft Pulp lignin. Two laccase isozymes (laccase I and II) have been purified. The reactivities of the two isozymes on all substrates tested, including kraft lignin, were similar, with no evidence of lignin depolymerization by either enzyme. However the presence of the mediator 2,2′-azinobis (3-ethylbenzthiazoline-6-sulphonate) (ABTS) prevented and reversed the polymerization of kraft lignin by either laccase. Both laccases were able to delignify kraft Pulp, but only in the presence of the mediator. Secreted MnP activity and the presence of substantial available Mn(II) ions appear necessary for delignification and Pulp brightening by T. versicolor. Mutants unable to secrete MnP cannot delignify. Purified MnP substantially delignifies Pulp when supplied with Mn (II), H2O2 and Mn (II)-complexing agents. Furthermore, the resulting Pulp is made easier to bleach to high brightness with alkaline hydrogen peroxide. LiP, while produced under secondary metabolic conditions, appears to play no role in the delignification of kraft Pulp by T. versicolor. White-rot fungi typically carry out net oxidation of the lignin and hydrolytic depolymerization of the carbohydrate in wood. Is there likely to be a significant role in delignification for enzymes which oxidize wood carbohydrates and reduce lignin? The family of carbohydrate-oxidizing, quinone-, metal ion- and organic free radical-reducing enzymes known as the cellobiose oxidases and cellobiose dehydrogenases (CBO, CDH, formerly CBQase) are reported to occur in a number of wood-degrading fungi. A CDH from T. versicolor has been purified, characterized and shown to decolorize and prevent laccase-mediated lignin polymerization. It can help supply MnP with chelator, hydrogen peroxide, and manganese. The rate of diffusion of enzymes or mediators in the kraft fiber wall may be a limiting factor for delignification. In order to visualize these diffusion bottlenecks we have built a model of the secondary wall and compared the pore sizes in the wall with the sizes of potential diffusible delignification agents.
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manganese peroxidase produced by trametes versicolor during Pulp Bleaching demethylates and delignifies kraft Pulp
Applied and Environmental Microbiology, 1993Co-Authors: M G Paice, I D Reid, R Bourbonnais, F S Archibald, L JurasekAbstract:Previous work has shown that Trametes (Coriolus) versicolor bleaches kraft Pulp brownstock with the concomitant release of methanol. In this work, the fungus is shown to produce both laccase and manganese peroxidase (MnP) but not lignin peroxidase during Pulp Bleaching. MnP production was enhanced by the presence of Pulp and/or Mn(II) ions. The maximum level of secreted MnP was coincident with the maximum rate of fungal Bleaching. Culture filtrates isolated from Bleaching cultures produced Mn(II)- and hydrogen peroxide-dependent Pulp demethylation and delignification. Laccase and MnP were separated by ion-exchange chromatography. Purified MnP alone produced most of the demethylation and delignification exhibited by the culture filtrates. On the basis of the methanol released and the total and phenolic methoxyl contents of the Pulp, it appears that MnP shows a preference for the oxidation of phenolic lignin substructures. The extensive increase in brightness observed in the fungus-treated Pulp was not found with MnP alone. Therefore, either the MnP effect must be optimized or other enzymes or compounds from the fungus are also required for brightening. Images
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kraft Pulp Bleaching and delignification by dikaryons and monokaryons of trametes versicolor
Applied and Environmental Microbiology, 1993Co-Authors: Katherine Addleman, F S ArchibaldAbstract:The ability of 10 dikaryotic and 20 monokaryotic strains of Trametes (Coriolus) versicolor to bleach and delignify hardwood and softwood kraft Pulps was assessed. A dikaryon (52P) and two of its mating-compatible monokaryons (52J and 52D) derived via protoplasting were compared. All three regularly bleached hardwood kraft Pulp more than 20 brightness points (International Standards Organization) in 5 days and softwood kraft Pulp the same amount in 12 days. Delignification (kappa number reduction) by the dikaryon and the monokaryons was similar, but the growth of the monokaryons was slower. Insoluble dark pigments were commonly found in the mycelium, medium, and Pulp of the dikaryon only. Laccase and manganese peroxidase (MnP) but not lignin peroxidase activities were secreted during Bleaching by all three strains. Their laccase and MnP isozyme patterns were compared on native gels. No segregation of isozyme bands between the monokaryons was found. Hardwood kraft Pulp appeared to adsorb several laccase isozyme bands. One MnP isozyme (pI, 3.2) was secreted in the presence of Pulp by all three strains, but a second (pI, 4.9) was produced only by 52P. A lower level of soluble MnP activity in one monokaryon (52D) was associated with reduced Bleaching ability and a lower level of methanol production. Since monokaryon 52J bleached Pulp better than its parent dikaryon 52P, especially per unit of biomass, this genetically simpler monokaryon will be the preferred subject for further genetic manipulation and improvement of fungal Pulp biological Bleaching.
L Jurasek - One of the best experts on this subject based on the ideXlab platform.
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kraft Pulp Bleaching and delignification by trametes versicolor
Journal of Biotechnology, 1997Co-Authors: F S Archibald, M G Paice, R Bourbonnais, L Jurasek, I D ReidAbstract:In 1989 we reported that the white-rot basidiomycete fungus Trametes versicolor could delignify and substantially brighten unbleached kraft Pulps. Since that time, considerable effort has been dedicated to understanding the biological mechanisms of this efficient delignification system in the hope that part or all of the system can be applied industrially. Early work indicated that all components necessary for extensive kraft Pulp Bleaching and delignification are secreted by the fungus, but that one or more of these components must be constantly replaced or renewed. T. versicolor can bleach O2-delignified and extended-cooking Pulps as well as conventional hardwood and softwood kraft Pulps. The fungus demethylates and solubilizes the residual lignin in the Pulps, seemingly without depolymerization. Enzyme families secreted by T. versicolor which may be involved in delignification include lignin peroxidases (LiP), manganese peroxidases (MnP), laccases, and cellobiose dehydrogenases (CDH). Each of these families has been investigated for its interactions with kraft Pulp lignin. Two laccase isozymes (laccase I and II) have been purified. The reactivities of the two isozymes on all substrates tested, including kraft lignin, were similar, with no evidence of lignin depolymerization by either enzyme. However the presence of the mediator 2,2′-azinobis (3-ethylbenzthiazoline-6-sulphonate) (ABTS) prevented and reversed the polymerization of kraft lignin by either laccase. Both laccases were able to delignify kraft Pulp, but only in the presence of the mediator. Secreted MnP activity and the presence of substantial available Mn(II) ions appear necessary for delignification and Pulp brightening by T. versicolor. Mutants unable to secrete MnP cannot delignify. Purified MnP substantially delignifies Pulp when supplied with Mn (II), H2O2 and Mn (II)-complexing agents. Furthermore, the resulting Pulp is made easier to bleach to high brightness with alkaline hydrogen peroxide. LiP, while produced under secondary metabolic conditions, appears to play no role in the delignification of kraft Pulp by T. versicolor. White-rot fungi typically carry out net oxidation of the lignin and hydrolytic depolymerization of the carbohydrate in wood. Is there likely to be a significant role in delignification for enzymes which oxidize wood carbohydrates and reduce lignin? The family of carbohydrate-oxidizing, quinone-, metal ion- and organic free radical-reducing enzymes known as the cellobiose oxidases and cellobiose dehydrogenases (CBO, CDH, formerly CBQase) are reported to occur in a number of wood-degrading fungi. A CDH from T. versicolor has been purified, characterized and shown to decolorize and prevent laccase-mediated lignin polymerization. It can help supply MnP with chelator, hydrogen peroxide, and manganese. The rate of diffusion of enzymes or mediators in the kraft fiber wall may be a limiting factor for delignification. In order to visualize these diffusion bottlenecks we have built a model of the secondary wall and compared the pore sizes in the wall with the sizes of potential diffusible delignification agents.
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manganese peroxidase produced by trametes versicolor during Pulp Bleaching demethylates and delignifies kraft Pulp
Applied and Environmental Microbiology, 1993Co-Authors: M G Paice, I D Reid, R Bourbonnais, F S Archibald, L JurasekAbstract:Previous work has shown that Trametes (Coriolus) versicolor bleaches kraft Pulp brownstock with the concomitant release of methanol. In this work, the fungus is shown to produce both laccase and manganese peroxidase (MnP) but not lignin peroxidase during Pulp Bleaching. MnP production was enhanced by the presence of Pulp and/or Mn(II) ions. The maximum level of secreted MnP was coincident with the maximum rate of fungal Bleaching. Culture filtrates isolated from Bleaching cultures produced Mn(II)- and hydrogen peroxide-dependent Pulp demethylation and delignification. Laccase and MnP were separated by ion-exchange chromatography. Purified MnP alone produced most of the demethylation and delignification exhibited by the culture filtrates. On the basis of the methanol released and the total and phenolic methoxyl contents of the Pulp, it appears that MnP shows a preference for the oxidation of phenolic lignin substructures. The extensive increase in brightness observed in the fungus-treated Pulp was not found with MnP alone. Therefore, either the MnP effect must be optimized or other enzymes or compounds from the fungus are also required for brightening. Images
I D Reid - One of the best experts on this subject based on the ideXlab platform.
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kraft Pulp Bleaching and delignification by trametes versicolor
Journal of Biotechnology, 1997Co-Authors: F S Archibald, M G Paice, R Bourbonnais, L Jurasek, I D ReidAbstract:In 1989 we reported that the white-rot basidiomycete fungus Trametes versicolor could delignify and substantially brighten unbleached kraft Pulps. Since that time, considerable effort has been dedicated to understanding the biological mechanisms of this efficient delignification system in the hope that part or all of the system can be applied industrially. Early work indicated that all components necessary for extensive kraft Pulp Bleaching and delignification are secreted by the fungus, but that one or more of these components must be constantly replaced or renewed. T. versicolor can bleach O2-delignified and extended-cooking Pulps as well as conventional hardwood and softwood kraft Pulps. The fungus demethylates and solubilizes the residual lignin in the Pulps, seemingly without depolymerization. Enzyme families secreted by T. versicolor which may be involved in delignification include lignin peroxidases (LiP), manganese peroxidases (MnP), laccases, and cellobiose dehydrogenases (CDH). Each of these families has been investigated for its interactions with kraft Pulp lignin. Two laccase isozymes (laccase I and II) have been purified. The reactivities of the two isozymes on all substrates tested, including kraft lignin, were similar, with no evidence of lignin depolymerization by either enzyme. However the presence of the mediator 2,2′-azinobis (3-ethylbenzthiazoline-6-sulphonate) (ABTS) prevented and reversed the polymerization of kraft lignin by either laccase. Both laccases were able to delignify kraft Pulp, but only in the presence of the mediator. Secreted MnP activity and the presence of substantial available Mn(II) ions appear necessary for delignification and Pulp brightening by T. versicolor. Mutants unable to secrete MnP cannot delignify. Purified MnP substantially delignifies Pulp when supplied with Mn (II), H2O2 and Mn (II)-complexing agents. Furthermore, the resulting Pulp is made easier to bleach to high brightness with alkaline hydrogen peroxide. LiP, while produced under secondary metabolic conditions, appears to play no role in the delignification of kraft Pulp by T. versicolor. White-rot fungi typically carry out net oxidation of the lignin and hydrolytic depolymerization of the carbohydrate in wood. Is there likely to be a significant role in delignification for enzymes which oxidize wood carbohydrates and reduce lignin? The family of carbohydrate-oxidizing, quinone-, metal ion- and organic free radical-reducing enzymes known as the cellobiose oxidases and cellobiose dehydrogenases (CBO, CDH, formerly CBQase) are reported to occur in a number of wood-degrading fungi. A CDH from T. versicolor has been purified, characterized and shown to decolorize and prevent laccase-mediated lignin polymerization. It can help supply MnP with chelator, hydrogen peroxide, and manganese. The rate of diffusion of enzymes or mediators in the kraft fiber wall may be a limiting factor for delignification. In order to visualize these diffusion bottlenecks we have built a model of the secondary wall and compared the pore sizes in the wall with the sizes of potential diffusible delignification agents.
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manganese peroxidase produced by trametes versicolor during Pulp Bleaching demethylates and delignifies kraft Pulp
Applied and Environmental Microbiology, 1993Co-Authors: M G Paice, I D Reid, R Bourbonnais, F S Archibald, L JurasekAbstract:Previous work has shown that Trametes (Coriolus) versicolor bleaches kraft Pulp brownstock with the concomitant release of methanol. In this work, the fungus is shown to produce both laccase and manganese peroxidase (MnP) but not lignin peroxidase during Pulp Bleaching. MnP production was enhanced by the presence of Pulp and/or Mn(II) ions. The maximum level of secreted MnP was coincident with the maximum rate of fungal Bleaching. Culture filtrates isolated from Bleaching cultures produced Mn(II)- and hydrogen peroxide-dependent Pulp demethylation and delignification. Laccase and MnP were separated by ion-exchange chromatography. Purified MnP alone produced most of the demethylation and delignification exhibited by the culture filtrates. On the basis of the methanol released and the total and phenolic methoxyl contents of the Pulp, it appears that MnP shows a preference for the oxidation of phenolic lignin substructures. The extensive increase in brightness observed in the fungus-treated Pulp was not found with MnP alone. Therefore, either the MnP effect must be optimized or other enzymes or compounds from the fungus are also required for brightening. Images
M G Paice - One of the best experts on this subject based on the ideXlab platform.
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kraft Pulp Bleaching and delignification by trametes versicolor
Journal of Biotechnology, 1997Co-Authors: F S Archibald, M G Paice, R Bourbonnais, L Jurasek, I D ReidAbstract:In 1989 we reported that the white-rot basidiomycete fungus Trametes versicolor could delignify and substantially brighten unbleached kraft Pulps. Since that time, considerable effort has been dedicated to understanding the biological mechanisms of this efficient delignification system in the hope that part or all of the system can be applied industrially. Early work indicated that all components necessary for extensive kraft Pulp Bleaching and delignification are secreted by the fungus, but that one or more of these components must be constantly replaced or renewed. T. versicolor can bleach O2-delignified and extended-cooking Pulps as well as conventional hardwood and softwood kraft Pulps. The fungus demethylates and solubilizes the residual lignin in the Pulps, seemingly without depolymerization. Enzyme families secreted by T. versicolor which may be involved in delignification include lignin peroxidases (LiP), manganese peroxidases (MnP), laccases, and cellobiose dehydrogenases (CDH). Each of these families has been investigated for its interactions with kraft Pulp lignin. Two laccase isozymes (laccase I and II) have been purified. The reactivities of the two isozymes on all substrates tested, including kraft lignin, were similar, with no evidence of lignin depolymerization by either enzyme. However the presence of the mediator 2,2′-azinobis (3-ethylbenzthiazoline-6-sulphonate) (ABTS) prevented and reversed the polymerization of kraft lignin by either laccase. Both laccases were able to delignify kraft Pulp, but only in the presence of the mediator. Secreted MnP activity and the presence of substantial available Mn(II) ions appear necessary for delignification and Pulp brightening by T. versicolor. Mutants unable to secrete MnP cannot delignify. Purified MnP substantially delignifies Pulp when supplied with Mn (II), H2O2 and Mn (II)-complexing agents. Furthermore, the resulting Pulp is made easier to bleach to high brightness with alkaline hydrogen peroxide. LiP, while produced under secondary metabolic conditions, appears to play no role in the delignification of kraft Pulp by T. versicolor. White-rot fungi typically carry out net oxidation of the lignin and hydrolytic depolymerization of the carbohydrate in wood. Is there likely to be a significant role in delignification for enzymes which oxidize wood carbohydrates and reduce lignin? The family of carbohydrate-oxidizing, quinone-, metal ion- and organic free radical-reducing enzymes known as the cellobiose oxidases and cellobiose dehydrogenases (CBO, CDH, formerly CBQase) are reported to occur in a number of wood-degrading fungi. A CDH from T. versicolor has been purified, characterized and shown to decolorize and prevent laccase-mediated lignin polymerization. It can help supply MnP with chelator, hydrogen peroxide, and manganese. The rate of diffusion of enzymes or mediators in the kraft fiber wall may be a limiting factor for delignification. In order to visualize these diffusion bottlenecks we have built a model of the secondary wall and compared the pore sizes in the wall with the sizes of potential diffusible delignification agents.
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manganese peroxidase produced by trametes versicolor during Pulp Bleaching demethylates and delignifies kraft Pulp
Applied and Environmental Microbiology, 1993Co-Authors: M G Paice, I D Reid, R Bourbonnais, F S Archibald, L JurasekAbstract:Previous work has shown that Trametes (Coriolus) versicolor bleaches kraft Pulp brownstock with the concomitant release of methanol. In this work, the fungus is shown to produce both laccase and manganese peroxidase (MnP) but not lignin peroxidase during Pulp Bleaching. MnP production was enhanced by the presence of Pulp and/or Mn(II) ions. The maximum level of secreted MnP was coincident with the maximum rate of fungal Bleaching. Culture filtrates isolated from Bleaching cultures produced Mn(II)- and hydrogen peroxide-dependent Pulp demethylation and delignification. Laccase and MnP were separated by ion-exchange chromatography. Purified MnP alone produced most of the demethylation and delignification exhibited by the culture filtrates. On the basis of the methanol released and the total and phenolic methoxyl contents of the Pulp, it appears that MnP shows a preference for the oxidation of phenolic lignin substructures. The extensive increase in brightness observed in the fungus-treated Pulp was not found with MnP alone. Therefore, either the MnP effect must be optimized or other enzymes or compounds from the fungus are also required for brightening. Images
Jeanclaude Sigoillot - One of the best experts on this subject based on the ideXlab platform.
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natural and recombinant fungal laccases for paper Pulp Bleaching
Applied Microbiology and Biotechnology, 2004Co-Authors: C Sigoillot, Eric Record, Peter J Punt, C A M J J Van Den Hondel, Jeanclaude Sigoillot, V Belle, J L Robert, Anthony Levasseur, A Fournel, M AstherAbstract:Three laccases, a natural form and two recombinant forms obtained from two different expression hosts, were characterized and compared for paper Pulp Bleaching. Laccase from Pycnoporus cinnabarinus, a well known lignolytic fungus, was selected as a reference for this study. The corresponding recombinant laccases were produced in Aspergillus oryzae and A. niger hosts using the lacI gene from P. cinnabarinus to develop a production process without using the expensive laccase inducers required by the native source. In flasks, production of recombinant enzymes by Aspergilli strains gave yields close to 80 mg l -1. Each protein was purified to homogeneity and characterized, demonstrating that the three hosts produced proteins with similar physico-chemical properties, including electron paramagnetic resonance spectra and N-terminal sequences. However, the recombinant laccases have higher Michaelian (Km) constants, suggesting a decrease in substrate/enzyme affinity in comparison with the natural enzyme. Moreover, the natural laccase exhibited a higher redox potential (around 810 mV), compared with A. niger (760 mV) and A. oryzae (735 mV). Treatment of wheat straw Kraft Pulp using laccases expressed in P. cinnabarinus or A. niger with 1-hydroxybenzotriazole as redox mediator achieved a delignification close to 75%, whereas the recombinant laccase from A. oryzae was not able to delignify Pulp. These results were confirmed by thioacidolysis. Kinetic and redox potential data and Pulp Bleaching results were consistent, suggesting that the three enzymes are different and each fungal strain introduces differences during protein processing (folding and/or glycosylation).
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overproduction of the aspergillus niger feruloyl esterase for Pulp Bleaching application
Applied Microbiology and Biotechnology, 2003Co-Authors: Eric Record, M Asther, C Sigoillot, Sandrine Pages, Peter J Punt, Michel Delattre, Mireille Haon, C A M J J Van Den Hondel, Jeanclaude SigoillotAbstract:A well-known industrial fungus for enzyme production, Aspergillus niger, was selected to produce the feruloyl esterase FAEA by homologous overexpression for Pulp Bleaching application. The gpd gene promoter was used to drive FAEA expression. Changing the nature and concentration of the carbon source nature (maltose to glucose; from 2.5 to 60 g l−1), improved FAEA activity 24.5-fold and a yield of 1 g l−1 of the corresponding protein in the culture medium was achieved. The secreted FAEA was purified 3.5-fold to homogeneity in a two-step purification procedure with a recovery of 69%. The overproduced protein was characterised and presented properties in good agreement with those of native FAEA. The recombinant FAEA was tested for wheat straw Pulp Bleaching, with or without a laccase mediator system and xylanase. Best results were obtained using a bi-sequential process with a sequence including xylanase, FAEA and laccase, and yielded very efficient delignification—close to 75%—and a kappa number of 3.9. This is the first report on the potential application of recombinant FAEA in the Pulp and paper sector.
