Pulping and bleaching studies of CAD deficient loblolly pines
Scott JT., Kadla JF., O'Malley DM., McKeand SE., Dimmel DR., Mackay JJ., Courchene C.
Mutant Loblolly Pine trees that possess a mutation for the Cinnamyl Alcohol Dehydrogenase (CAD) gene have been shown to have abnormal lignin. They are shown to incorporate novel monomers into the lignin polymer, suggesting alternative pathways in lignin biosynthesis. They have shown to be more easily delignified, but their pulp yields are low and the trees possess a high rate of mortality. Four- and six-year-old partially CAD-deficient trees are approx. 25% more easily delignified than their control counterparts. Four-year-old partially CAD-deficient bleached pulp also shows better strength properties. By contrast, fourteen-year-old trees do not seem to possess the same beneficial delignification rates and bleachability. Surprisingly, these same fourteen-year-old partially CAD-deficient trees grow faster than their wild type controls. This result suggests the possibility of producing more wood per acre using plantations of these naturally occurring mutants. Additional trees from other sources will be examined to verify the observed results. The lignin structures in CAD-deficient trees are being compared to understand the delignification trends; lignin analyses will be discussed.