Development of enzymatic pulp and paper applications

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Canada is the largest exporter of pulp and paper products in the world. Employing about 70,000 Canadians, this industry is of strategic importance to the economy of the country. To maintain its global competitiveness, the industry has identified among others three processes for biocatalyst intervention: bleaching, pulping, and removal of wood extractives. The increased use of biocatalysts (enzymes) in these processes are expected to reduce the cost of production, minimize adverse environmental impact, lower the consumption of energy, and yield superior paper products. White-rot fungi are known for their ability to completely hydrolyze wood. Phanerochaete chrysosporium is the most intensively studied white-rot fungus. This fungus or extracellular enzymes isolated from it has been used for pulping and bleaching of wood. However, the enzyme combinations for efficient bleaching, pulping, and hydrolysis of wood extractives are not fully understood. The genome of P. chrysosporium has recently been completely sequenced and annotated. We have constructed a DNA microarray representing over 5,000 genes of this species. The availability of these genomic resources affords the systematic analysis of genes involved in wood degradation. We propose to examine the gene expression profiles of P. chrysosporium under conditions that promote bleaching, pulping, and hydrolysis of wood extractives. Genes encoding extracellular proteins that are up-regulated under the above conditions will be cloned and expressed in a robust cell factory. The recombinant proteins will be characterized biochemically. They will also be tested individually and in combination for their utility in pulp and paper processes. Results from the proposed research will enhance significantly our knowledge of biological degradation of wood. They will also be used to guide the development of novel enzyme applications for the pulp and paper industry.