Scientists discover how to convert trees into sustainable industrial chemicals
In a major breakthrough for sustainable production of industrial chemicals, a team of researchers from North Carolina State University, has found a specific molecular property in lignin that determines how it degrades and converts into useful substances. The scientists have identified the methoxy content in lignin, which brings us closer to producing industrial chemicals from trees, an eco-friendly alternative to petroleum-derived products.
The role of bacteria in lignin degradation
Led by Robert Kelly, the research team had previously shown that some thermophilic bacteria could digest the cellulose in trees. But, the process wasn't efficient enough for industrial chemical production. "In other words, not at the level that would make economic and environmental sense for producing industrial chemicals," Kelly explained. This prompted further investigation into the molecular properties of lignin.
CRISPR and lignin: A decade-long research journey
For more than a decade, Kelly has worked with Associate Professor Jack Wang to tackle the high lignin content in trees. In 2023, Wang's team employed CRISPR genome editing tech to develop poplar trees, with modified lignin content and composition. These GM trees were then tested for their suitability for microbial degradation and fermentation, showing that bacteria have different appetites for different types of plants.
Bacterial preferences and lignin methoxy content
In their study, Kelly and Bing used a genetically engineered bacterium to break down Wang's engineered poplar trees with different lignin contents. They found that trees with lower lignin methoxy content were more easily degraded. "This cleared up the mystery of why lower lignin alone is not the key—the devil was in the details," Kelly said. "Low methoxy content likely makes the cellulose more available to the bacteria."
Engineered poplars: A promising resource for industrial chemicals
The engineered poplars with low lignin and methoxy content hold promise for producing chemicals through microbial fermentation. While these trees have been successfully grown in greenhouses, the results of field testing are still awaited. If successful, this could pave the way for large-scale production of chemicals from poplar trees using microbes, now that the key marker - methoxy content - has been identified.
