In situ microscopic investigation of plant cell walls deconstruction in biorefinery

Plant biomass that primarily composed of polysaccharides and lignin constitutes a renewable energy source. The conversion of biopolymers into fuels, energy, and chemicals with a concept of biorefinery involves a chemical/biological treatment to facilitate components release performance. However, the accurate understanding of cellular architecture of plant cell walls remains unclear owing in part to complexity of biomass chemical structures as well as limitations of traditional analytical methods that may bring irreversible modifications. In situ microscopic techniques are readily required to visualize, characterize, and quantify the dynamic features of plant cell walls following treatments on multi-scale levels. This review gives insights into the recent contributions of a series of non-destructive techniques including confocal laser scanning microscopy, confocal Raman microscopy, FT-IR imaging microscopy, and atomic force microscopy to the field of biorefinery, focusing on the deconstruction of plant tissues. We also highlight the critical outlook and scientific challenges on the study of biomass utilization as well as microscopy applications.