Microbial degradation of tree bark – how, and by whom?

The bark of trees has a very important protective role, partly physical, but also chemical as it is the first line of defense against environmental stress and attacks by various pathogens.

Despite its protective features, largely attributed to an enrichment of so-called extractive compounds relative to the underlying wood, bark is degraded in nature.

Surprisingly, virtually nothing is known about this degradation on a molecular level, meaning that a huge knowledge gap exists for a global and major process ongoing throughout a wide variety of biotopes.We recently published a holistic study on how spruce bark can be degraded by a microbial consortium, which was the first in its kind to follow both the chemical changes and the community structure over long time periods, and this has inspired the proposed larger project.

Major questions to answer concern from where the degrading organisms principally derive – the tree surface, the soil, or the industrial site where the bark was sourced?

In this project, one major goal is to follow the degradation of multiple bark types, to discern whether they also contain key molecules that greatly inhibit growth, such as the resin acids found in spruce bark, and which enzymes are mainly involved in especially the modification and detoxification of bark extractives.

This will be done using a range of complementary methods, and the studies will be supported by excellent international collaborations.