Types of lignin, properties, and structural characterization techniques

Abstract The chemical structure of lignin, that is, the monolignols and their linkages, is dependent on the biomass type and the procedure used for lignin isolation. The resulting structural differences also influence the lignin’s properties such as antioxidant and antimicrobial activity, which are here presented and discussed including most recently reported data. There is a high potential in the usage of multivariate data processing (e.g., nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectra) in current lignin structure analysis and quality control. Current studies in lignin valorization focus applications in biomedicine such as lignin-based drug release and scaffolds for stem cell–based tissue engineering, both will briefly be presented.