LAUSR

Abstract Lignin is the major components limiting enzymatic hydrolysis and normally removed by acidified sodium chlorite in laboratory. However, the information on delignification kinetics and selectivity at cellular level as the reaction proceeds is limited. In this work, the dynamic removal of lignin and its monolignol in different cell types of poplar were visualized in real time by confocal Raman microscopy. At the initial stage, substantial reduction in lignin concentration was observed especially in cell corner and compound middle lamella of fiber, but the removal rate slowed down in the following process. Delignification was highly cell-selective that the vessel was the most resistant to delignification followed by ray and then by fiber. Besides, the removal behavior of lignin monomers in ray varied significantly with vessel and fiber. In the whole process, the syringyl units was more prone to being removed than guaiacyl units. This information could lead to a better understanding of the delignification process of lignocellulosic biomass by chlorite treatment.