Researchers Dr Fiona Whelan, a Cryo-electron Microscopist from Adelaide Microscopy at the University of Adelaide, have identified a novel enzyme capable of transforming lignin, a complex polymer found in plant cell walls, into valuable chemicals using hydrogen peroxide. This discovery offers a more sustainable alternative to traditional methods that often involve high temperatures, strong acids, and toxic solvents.
Harlington, A. C., Das, T., Shearwin, K. E., Bell, S. G., & Whelan, F. (2025). Structural insights into S-lignin O-demethylation via a rare class of heme peroxygenase enzymes. Nature Communications, 16(1), 1815. https://doi.org/10.1038/s41467-025-57129-6
Lignin is a major component of plant biomass, providing structural support to plants. However, during processes like paper production and biofuel generation, lignin is often discarded as waste. Globally, approximately 100 million tonnes of lignin are produced annually, primarily from forestry and agricultural residues. Traditionally, converting lignin into valuable products has been challenging due to its complex structure and resistance to degradation.
The breakthrough centers on an enzyme derived from the soil bacterium Amycolatopsis thermoflava. This enzyme, a rare class of heme peroxygenase, facilitates the O-demethylation of S-lignin-derived monolignols using hydrogen peroxide. This reaction is crucial for converting lignin into simpler compounds that can be further processed into valuable chemicals such as fragrances, flavorings, and pharmaceuticals. The use of hydrogen peroxide as a co-substrate makes the process more environmentally friendly compared to traditional methods that rely on toxic chemicals.
Dr Fiona Whelan, a Cryo-electron Microscopist from Adelaide Microscopy at the University of Adelaide stated,
“Traditional chemical processes for the synthesis of these types of chemicals rely on petroleum-based starting compounds and heavy metal catalysts, making them non-renewable and inherently toxic processes. This new catalytic processing method will support the development of other new green chemistry ‘enzyme factories’ or biorefineries to turn the lignin and other biological waste streams into a valuable repository of fine chemicals.”
This discovery has significant implications for green chemistry and the development of biorefineries. By utilizing enzymes like the one from Amycolatopsis thermoflava, it is possible to convert lignin and other biological waste streams into a repository of fine chemicals. This approach aligns with the principles of green chemistry by reducing the reliance on petroleum-based feedstocks and minimizing environmental impact.
Ongoing research aims to further understand the mechanisms of lignin degradation and to optimize the enzyme’s efficiency. Additionally, efforts are underway to explore the potential of other microorganisms and enzymes in lignin valorization. The ultimate goal is to develop scalable processes that can be integrated into existing industrial systems, contributing to a more sustainable and circular economy.
The findings were published in Nature Communications and represent a significant step forward in the field of biocatalysis and sustainable chemical production.
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
