Changes in wood chemistry could have significant impact on both environmental and economic
aspects of the pulp and paper industry. Consequently, a considerable amount of effort has been
devoted to altering lignin content and/or modifing lignin monomer composition, a cell wall
component whose removal is a major part of the chemical pulping process. Analysis of poplar
transformed with a cinnamate 4-hydroxylase (C4H):ferulate5-hydroxylase (F5H) construct
confirmed significant increases in the mole percent syringyl lignin in transgenic lines. Further,
this study demonstrated significant increases in pulping efficiency from greenhouse grown
transgenic trees. Compared to wild-type pulp, decreases of 23 kappa units (residual lignin) and
increases of >20 ISO brightness units were observed in tree lines exhibiting high syringyl
monomer concentrations (93.5% mol S). These changes were associated with no significant
change in total lignin content or observed phenotypic differences in the trees. Additionally,
pulp yields were not affected by the enhanced removal of lignin.. Furthermore, transgenic lines
exhibit reduced fibre coarseness and increased cellulose viscosity. These results suggest that
C4H-F5H transformed trees could be used to produce pulp for paper with substantially less
severe delignification conditions (lower chemical loading or less energy), and that the pulp
produced is of comparable quality to that of the wild-type poplar. Consequently, the ecological
footprint left on the environment, measured by the amount of deleterious pulping by-products
released into the environment may be significantly reduced.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/14351 |
| Date | 11 1900 |
| Creators | Huntley, Shannon Kelly |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Relation | UBC Retrospective Theses Digitization Project [http://www.library.ubc.ca/archives/retro_theses/] |
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