The efficient and sustainable utilization of plant biomass for the production of bioenergy is one of today`s key technological challenges. The recalcitrant nature of plant cell walls is a main barrier for their degradation and limits the viability of biorefinery processes. Wood-decaying fungi may hold the key to solve this problem. First authors Daniel Kracher and Stefan Scheiblbrandner together with their colleagues Alfons K. G. Felice, Erik Breslmayr, Marita Preims, Karolina Ludwicka, Dietmar Haltrich and Roland Ludwig from the Department of Food Science and Technology (BOKU) in collaboration with Vincent Eijsink (NMBU, Norway) studied fundamental mechanisms of wood rotting fungi to degrade lignocellulosic substrates.
Lytic polysaccharide monooxygenase (LPMO) plays a key role in this process. Its ability to degrade highly resistant parts of cellulose boosts the performance of the long known cellulolytic enzyme machinery. The work reveals the strategies of different fungi to ensure activation of LPMO under different environmental conditions. The team discovered that white-rot fungi employ a specific partner enzyme (cellobiose dehydrogenase) to directly activate LPMO, while brown-rot fungi often rely on other oxidative enzymes that activate LPMO indirectly via wood derived phenols. Depending on the availability of such phenols, some fungi are also able to secrete these compounds in order to maintain LPMO activity. This allows fungi to specifically adapt to different growth conditions or habitats.
The scientists believe that these discoveries will help to improve the performance of commercial enzyme mixtures used for the transformation of biomass into fuels and base chemicals.
Link to the publication: science.sciencemag.org/content/early/2016/04/27/science.aaf3165
This work was funded by the European Commission (project “INDOX”) the PhD programme BioToP (https://biotop.boku.ac.at), the joint PhD programme IGS BioNanoTech (https://www.nano.boku.ac.at/igs-bionanotech/) and the DOC programme of the Austrian Academy of Sciences (www.oeaw.ac.at).