Etherases to break covalent bonds between lignin and hemicellulose

Research Project, 2017

This is a hypothesis-testing project aiming to find new types of enzymes able to break the strong ether bonds between lignin and hemicellulose in plant biomass. Lignin binds to hemicellulose in plant cell walls, and glues the structure together. Lignin adversely affects enzymes and its degradation products also inhibit microbial growth. This reduces the efficiency of biomass hydrolysis and fermentation in a range of biorefinery concepts. We have recently discovered ester bond cleaving enzymes, but ether-cleaving enzymes are still unknown. In nature we however do not see an accumulation of lignin-carbohydrate complexes, and thus enzymes able to break these bonds must exist. This project will try to discover ether-cleaving enzymes in a large number of wood decaying fungi (brown- and white rot) which likely produce enzymes with the desired activities. This will be done by screening of produced fungal enzymes using newly synthesized model substrates.