Possible Applications of Cellobiose Oxidizing and Other Flavine Adenine Dinucleotide Enzymes in the Pulp and Paper Industry

Abstract

Properties of the cellobiose oxidizing enzymes cellobiose:quinone oxidoreductase (CBQ) and cellobiose dehydrogenase (CDH) are outlined and comparison made with veratryl alcohol oxidase (VAO). Their importance for lignin and cellulose degradation by white-rot fungi is discussed as well as their possible use for applications in the pulp and paper industry. These applications include iron(III) and quinone reduction, studies on yellowing of paper, and (ligno)cellulose fibre characterization. Shortening of fibres and mechanical weakening of fibres by enzymes takes place most rapidly at specific sites of high acessibility, i.e. "nodes", along the fibre axis. The strongest attack on nodes is obtained with CDH + exoglucanase or with exo--and endoglucanases together. Experiments with exo-, endoglucanases and CDH have shown that neither of the cellulases can perform cleavage on their own. It is proposed that exoglucanases first release cellobiose, which is then used for oxidoreductive attack by CDH on pulp fibres.Wood and lignocellulose are degraded by a mixture of enzymes attacking the different components lignin, cellulose and hemicellulose (1). At present the most important lignin-degrading enzymes are lignin peroxidase, Mn-peroxidase and laccase which are produced mainly by white-rot basidiomycetes. They degrade lignin by catalyzing one-electron oxidation of lignin and its degradation products. The resulting radical products undergo a variety of non-enzymatic coupling, 3

Cellobiose Dehydrogenase – A Flavocytochrome from Wood-Degrading, Phytopathogenic and Saprotropic Fungi

“…Several authors suggested that CDH could be used as part of an enzyme complex to modify or break down cellulose and lignin in the pulp and paper industry [131]. The suggestion was to use it similar to other ligninolytic enzymes in the presence of complexed iron [112].…”

Study of the mechanical behavior of recycled fibers. Applications to papers and paperboards.

“…At the dislocated region, fibre cell wall is loosened up resulting in a change of MFA [101] and separation of microfibrils. Therefore, the accessibility of cell wall elements at the dislocations to the chemical hydrolysis by the acids, enzymes and other agents is increased [96,31,32]. Fibre wall thickness 10 −06 Micro structure 10 −07 10 −08 Ultra structure 10 −09 10 −10 Molecular structure Figure 2.11: Slip plane and compression failure adapted from [227,125] Fibre wall deformations has been observed and characterised by polarised light [186,227], stains [118], enzymes [31], swelling agents [209] and acid cleavage [29].…”

“…Therefore, the accessibility of cell wall elements at the dislocations to the chemical hydrolysis by the acids, enzymes and other agents is increased [96,31,32]. Fibre wall thickness 10 −06 Micro structure 10 −07 10 −08 Ultra structure 10 −09 10 −10 Molecular structure Figure 2.11: Slip plane and compression failure adapted from [227,125] Fibre wall deformations has been observed and characterised by polarised light [186,227], stains [118], enzymes [31], swelling agents [209] and acid cleavage [29]. Fibre wall deformations with reference to wood fibres has been reviewed by Wilkins [238] whereas the review from Nyholm et al [166] was focused on pulp fibres.…”

“…Cell wall thickness, Les points faibles de la paroi fibreuse peuvent être considérés comme des dislocations dans celle-ci. Ces défauts locaux permettent de pouvoir les hydrolyser par voie chimique ou enzymatique [31,32,96]. Ander et Daniel [29] quantifient ces points faibles en définissant un indice de clivage chimique des fibres (cf.…”

Phanerochaete chrysosporium Cellobiohydrolase and Cellobiose Dehydrogenase Transcripts in Wood

“…In addition to the hydrolytic cellulases, extracellular oxidative enzymes apparently are involved in cellulose degradation by P. chrysosporium and, presumably, other white rot fungi (3,15). Cellobiose dehydrogenase (CDH) is an extracellular enzyme containing two domains; one domain contains flavin adenine dinucleotide, and the other domain contains a heme (18,19).…”