Development of enzymatic pulp and paper applications

加拿大是世界上最大的纸浆和纸制品出口国。该行业雇用了约70,000名加拿大人，对该国经济具有战略重要性。为了保持其全球竞争力，该行业已经确定了生物催化剂干预的三个过程：漂白、制浆和去除木材抽出物。在这些过程中增加生物催化剂(酶)的使用有望降低生产成本，最大限度地减少对环境的不利影响，降低能源消耗，并生产出优质的纸制品。白腐菌以其完全分解木材的能力而闻名。黄孢原毛平革菌是研究最深入的白腐菌。这种真菌或从其分离出的胞外酶已被用于木材的制浆和漂白。然而，用于有效漂白、制浆和木材抽出物的水解酶的组合还不完全清楚。黄孢假单胞菌的基因组最近已经完全测序和注释。我们已经构建了一个DNA微阵列，代表了这个物种的5000多个基因。这些基因组资源的可获得性为系统分析参与木材降解的基因提供了基础。我们建议研究在促进木材提取物漂白、制浆和水解物的条件下，黄孢原毛杆菌的基因表达谱。在上述条件下上调的编码胞外蛋白的基因将被克隆并在一个强大的细胞工厂中表达。重组蛋白将进行生化表征。还将单独和组合测试它们在纸浆和造纸过程中的效用。拟议的研究结果将极大地提高我们对木材生物降解的认识。它们还将用于指导纸浆和造纸工业新型酶应用的开发。

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.