CELL 187 - Correlating structural features of lignin with physical properties: Toward a descriptive-predictive database

The efficient use of all available biomass components is of utmost interest with respect to a sustainable use of renewable resources. Lignin as the second most-abundant component in forest biomass is, however, currently not exploited to its fullest potential. The straight-forward use is impeded by several lowdowns on the molecular level: i) the structures of isolated lignins differ depending on the isolation process; ii) the size of poly- and oligomeric structures are very different among different lignins; iii) the distribution and or abundance of basic building blocks and bonding motifs differ among different lignins. Current research efforts are aiming at a better understanding of both, the structural features of isolated lignins, and the physical properties of isolated lignins, fractionated isolated lignins, and chemically modified lignins. These important research activities – detailed structural characterisation and determination of physical properties – should be closely linked, however, for different types of lignins, to arrive at a more fundamental understanding of lignin: a descriptive model for lignin that would also allow predictions of physical properties based on structural features, and vice versa, would drastically simplify any work related to the valorisation of lignin. In an all-encompassing approach for the characterisation of lignin, physical data such a glass transition temperature, decomposition temperature, etc. that were obtained for a collection of representative types of lignins as well as fractions thereof, were correlated systematically with detailed structural features and molecular mass key data to form a database that can serve as quick reference for the selection of the right lignin type for a envisaged application. Current efforts are aimed at adding functionalised lignins to this database.