Scientists at North Carolina State University have genetically engineered poplar trees to be more easily broken down by microbes, paving the way for sustainable chemical production. This breakthrough offers a promising solution to reduce reliance on fossil fuels by using trees as an eco-friendly alternative for producing industrial chemicals.

Modifying Lignin with CRISPR Technology

The research team, led by Dr. Robert Kelly and Associate Professor Jack Wang, focused on altering lignin—a complex polymer that gives trees strength and resistance to decay but also makes them difficult to decompose for biofuel production. Using CRISPR genome editing technology, they created poplar trees with modified lignin content and composition. Poplar trees were chosen because they grow quickly, require minimal pesticides, and can thrive on marginal lands unsuitable for food crops.

Discovery of Methoxy Content’s Importance

The scientists identified that the methoxy content of lignin determines how easily microbial fermentation can break down plant matter. Dr. Kelly explained that this discovery “cleared up the mystery of why lower lignin alone is not the key — the devil was in the details. Low methoxy content likely makes the cellulose more available to the bacteria.”

Utilizing Thermophilic Bacteria

The team employed a thermophilic bacterium, Anaerocellum bescii, known for thriving in extreme environments like hot springs. Former Ph.D. student Ryan Bing noted that these bacteria “have varying appetites for different types of plants.” By studying how the bacteria consume plant matter with various compositions, the researchers found that lowering the methoxy content in lignin makes the trees more digestible for microbial fermentation.

Advantages for Sustainable Chemical Production

The modified poplars can be converted into industrial chemicals such as acetone and hydrogen gas with favorable economic outcomes and low environmental impact. Using engineered microbes to break down lignin offers benefits like lower energy requirements and reduced environmental impact. Dr. Kelly pointed out that microbes “not only break down the cellulose but also ferment it to products, such as ethanol – all in one step.”

Ongoing Field Trials and Future Implications

While the engineered poplars perform well in greenhouse conditions, field trials are underway to assess their viability in real-world environments. This advancement provides researchers with a specific target for producing poplar lines best suited for chemical production through microbial fermentation.

Addressing Climate Change and Environmental Benefits

Postdoctoral researcher Daniel Sulis emphasized the broader impact: “One promising solution lies in harnessing trees to meet society’s needs for chemicals, fuels and other bio-based products while safeguarding both the planet and human well-being.”

“These findings not only move the field forward but also lay the groundwork for further innovations in using trees for sustainable bio-based applications,” Sulis added.

Conclusion

As the world grapples with climate change and the need to reduce dependence on fossil fuels, this research offers a significant step toward sustainable alternatives. By genetically modifying trees to be more compatible with microbial fermentation, scientists are opening new avenues for eco-friendly chemical production that could benefit both the economy and the environment.