In-situ visual delignification and cell-scale kinetics modeling using confocal Raman microscopy.

Efficient delignification remains a critical technological bottleneck hindering the valorization of plant cell wall resources. Plant cell walls are dynamic, spatially heterogeneous networks characterized by a highly interconnected physical architecture and complex chemical composition. In-situ visualization of delignification dynamics at the cell scale, coupled with a quantitative understanding of cell-specific delignification kinetics, provide a powerful approach for a deeper understanding of the delignification process. In this study, Confocal Raman microscopy mapping was employed to obtain lignin content and visualize the in-situ delignification process in different tissues and cells from rice stem, including parenchyma, sclerenchyma, protoxylem, vascular bundle sheath, epidermis, metaxylem, and external vascular bundle. Results revealed pronounced cell-type-dependent delignification responses, further supporting the concept that recalcitrance is not solely determined by lignin content per se. Furthermore, this study established, for the first time, the delignification kinetic models for these distinct tissues and cells, providing a quantitative framework for describing lignin content dynamics during acidified sodium chlorite delignification process. This study offers a valuable approach for understanding and optimizing cell-type-specific responses during the implementation of delignification strategies.