Lignin is an aromatic cell wall polymer that acts as a water-proof shield in plant cells. Lignin constitutes 20-30 % of lignocellulosic biomass and is an underexploited resource in biomass refining. Certain fungi and bacteria can degrade lignin using different enzymatic strategies, notably by oxidative enzyme systems. A new type of microbial hydrolytic enzymes, β-etherases (no EC number), have been shown to catalyze selective hydrolytic lignin bond cleavage, i.e. different to oxidative enzymes that attack by generating radicals. An extracellular fungal β-etherase, from a Chaetomium sp., appears to act on lignin model compounds by a simple mechanism only dependent on H2O. The objective is to explore these new hydrolytic fungal β-etherases by genomic-based explorative approaches coupled with assessment of β-etherase catalysis on lignin. My aim is to provide new knowledge of biocatalytic lignin degradation and to assess whether β-etherases can depolymerize lignin in biorefinery processes.
