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

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.