It is now well recognized that burning fossil fuels and deforestation are major contributors to climate change, and that plant biomass can serve as a renewable and potentially carbon-neutral raw material for the production of bioenergy and a variety of other biobased products. The major long-term goal of the Bioenergy and Bio-aromatics group is to engineer plant cell wall composition for a more cost-effective conversion of plant biomass into fermentable sugars or aromatic building blocks, without adversely affecting plant yield. As lignin needs to be depolymerized for both purposes, we focus on understanding the biosynthesis, polymerization and structure of lignin, and how lignin biosynthesis integrates into plant metabolism and development. In addition to lignin and cell wall polysaccharides, plant biomass also contains thousands of molecules of which the structures, and hence the properties, have remained unknown for the simple reason that is difficult to purify them for structural elucidation by NMR. The group has a major activity in characterizing these metabolites. Arabidopsis, maize and poplar are used as a model species for gene and metabolite discovery. Field trials are made to investigate the new traits in a relevant environment.

Identifying new genes in aromatic metabolism

When improving plant cell walls, it all comes down to identifying the genes that are involved in the biosynthesis of the major cell wall polymers, and altering their expression levels in target crops such as poplar and maize. From co-expression data sets, we have identified a set of candidate genes that likely play an important role in phenolic biosynthesis. We have already demonstrated the role of some of these in lignin biosynthesis (Vanholme et al., 2012; 2013; Sundin et al., 2014). Our expertise in comparative metabolite profiling and mass spectrometry is a great asset to help elucidating their function. The potential for applications of these genes is investigated by analysing the biomass composition and saccharification potential of the corresponding mutants, and by translating this research to maize and poplar. Double mutants are made to test for additive or synergistic effects (de Vries et al., 2018).