Depolymerization of Lignin by Coordinated Copper and Peroxide and its Effect on Wood, 2000 Pulping / Process & Product Quality Conference Proceedings

K. Messner, K. Fackler, K. Koller, P. Lamaipis, E. Srebotnik, W. Gindl, T. Watanabe--The investigation of selectively delignifying white rot fungi, as used for biopulping led to the detection of a diffusible low molecular weight delignifying system composed of copper, a coordinator and peroxide. As peroxide hydrogen peroxide as well as organic hydroperoxides may be used. Experiments with model compounds showed that this system is able to depolymerize highly recalcitrant non-phenolic lignin. The development of a new technique allowed to evaluate the potential of the copper system to depolymerize native lignin. It is shown that with organic hydroperoxides native wood cell wall lignin may be completely dissoluted. The middle lamella is delignified faster than the S2-layer. Generally, organic peroxides are more efficient than hydrogen peroxide. Besides the fact that this system highly matches the result of selectively delignifying white rot fungi, it is of great interest for eventual applications in pulp bleaching or pretreatment of lignocellulosic substrates.