Investigating fungi and bacteria for lignin degradation

May 25, 2021

Two rows of four petri dishes lined up with different types of lignin-degrading fungi from boreal forest ecosystems growing in them.

Lignin-degrading fungi from a boreal forest ecosystem.

In a forest ecosystem, brown rot fungi play a dominant role in decomposing and recycling carbon sources sequestered in tree biomass. However, the carbohydrate-selective nutritional mode of these fungi do not allow them to consume all forms of carbon in wood, leaving abundant amounts of lignin in solid form as residues. The lignin residues represent a recalcitrant carbon pool in the forest ecosystem and their fate remains unknown. In this research project, Singh will investigate the functional microbes, as well as the interactive microbial mechanisms involved in the utilization and degradation of lignin. Bacteria and fungi isolated from the same niche can interact with each other to utilize/degrade lignin. Singh is looking to take advantage of this natural process, utilizing the accelerated evolution in the laboratory to domesticate a stable microbial consortium for accelerated degradation of lignin. Lignin is the second most abundant biopolymer on Earth and provides structural support to plant materials, however due to its complex structure and heterogeneity, it is difficult to degrade. Lignin degradation products can have important industrial applications, therefore understanding the degradation mechanisms is important for its effective utilization.  Singh hopes to apply the research to bioremediate recalcitrant soil and water pollutants such as polycyclic aromatic hydrocarbons (PAHs) as they have similar structural and chemical complexity as lignin molecules.

Q: Why is this work important, both to you, and to people in general? 

A: Lignin is the second most abundant polymer in the world and is highly recalcitrant. Its removal (or degradation) represents a key step for carbon recycling in land ecosystems as well as a central issue for industrial utilization of plant biomass. Therefore, this work is important to understand and to create bio-products that can be beneficial to the people and the environment in general.

Q: What has been the most rewarding aspect of your project so far? 

A: Being part of a novel research that has benefits to the environment. 

Q: Is there a clear vision of what you hope your research project’s impact will be, and has that vision changed from the start of your project to present day? 

A: Through this research we hope to establish a pollutant degradation system that not only breaks down lignin, but can also break down other recalcitrant pollutants in order to efficiently utilize the byproducts of this process, or get rid of harmful pollutants.