Enzymatic lignin depolymerization by beta-etherases

Name of applicant

Line Munk


DKK 564,794



Type of grant

Internationalisation Fellowships


This project pursue the aim of enzymatically depolymerizing lignin by an overlooked enzyme group of β-etherases. Lignin is a complex aromatic polymer in plant biomass, which lignin-degrading microorganisms attack by secreting oxidative enzymes. A common feature of these oxidative enzymes is radical-based mechanisms by which they attack lignin, causing random reactions. More selective enzymes i.e. β-etherases, target bond cleavage of the most common bond in lignin. They may be suitable enzymatic tools to achieve lignin depolymerisation. The objective is to gain insight into how β-etherases act on real lignin, which provides new knowledge of lignin turnover in nature, and help assess whether β-etherases can facilitate depolymerisation of lignin in biorefinery processes.


Lignin is of high interest due to the potential value of aromatic monomers derived from lignin. Currently, lignin is regarded as a bi-product of biorefineries, used only for combustion to cover the internal energy consumption of the biorefineries. β-etherases are believed to enable selective bond cleavage of the most abundant type of linkage in native lignin, the β-O-4 ether linkages. Improved knowledge on β-etherases and how they act on real lignin, may contribute to paving the way for enzymatic upgrading of lignin and make the economy of biorefineries more viable.


Initially the research will focus on the discovery and identification of β-etherases for recombinant expression via genomic-bioinformatics analysis. Selected candidates will be characterised by kinetic studies and selective bond-cleavage analyses. A collaborative stay at VTT Technical research center of Finland provides a unique opportunity to access the most advanced methods within lignin analysis and enzyme radiolabelling technology. Having access to these methods, changes in lignin following β-etherase catalysis will be identified and assessed to elucidate action of β-etherases on real lignin.

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