Researchers have enhanced poplar trees through genetic modification to create high-performance, structural wood without relying on harmful chemicals or energy-consuming methods.
At the University of Maryland, scientists have altered poplar trees genetically to generate strong, structured wood sustainably, avoiding the need for chemicals and extensive energy use. Engineered wood, derived from regular wood, is increasingly viewed as a green alternative to conventional building materials such as steel, cement, glass, and plastic. It also holds potential for long-term carbon storage since it is less prone to decay compared to standard wood, aiding in carbon emission reduction efforts.
However, achieving genuine sustainability with engineered wood is challenging due to the requirement of processing it with hazardous chemicals and utilizing substantial energy, which creates significant waste. The team modified a single gene in living poplar trees, allowing them to grow wood ready for engineering without additional processing.
This research was published online on August 12, 2024, in the journal Matter.
“We are thrilled to showcase a novel approach that merges genetic engineering with wood engineering to sustainably sequester and store carbon in a resilient super wood form,” stated Yiping Qi, a professor in the Department of Plant Science and Landscape Architecture at UMD and a lead author of the study. “Carbon sequestration is vital in combating climate change, and such engineered wood could have numerous applications in the emerging bioeconomy.”
Before wood can be modified to enhance its structural properties—such as boosting strength or UV resistance, allowing it to replace materials like steel or concrete—it needs to have a key element called lignin removed.
Previously, researchers at UMD had successfully devised methods to eliminate lignin using various chemicals, while others have looked into using enzymes and microwave techniques. In this latest research, Qi and his colleagues aimed to create a method that doesn’t depend on chemicals, generates waste, or consumes large amounts of energy.
By employing a technique known as base editing to deactivate a crucial gene called 4CL1, the researchers succeeded in cultivating poplar trees with 12.8% less lignin compared to typical wild-type poplars, which is similar to levels attained through chemical processing of engineered wood products.
Qi and his research team cultivated the modified trees alongside unaltered trees in a greenhouse for six months, noting no differences in growth rates or structural integrity between the genetically modified and unmodified trees.
To assess the practicality of their genetically altered poplar, the team, led by Liangbing Hu, a professor of materials science and engineering, created small samples of high-strength compressed wood resembling particle board, which is commonly utilized in furniture manufacturing.
Compressed wood is produced by submerging wood in water under a vacuum and subsequently hot-pressing it to reduce its thickness to about one-fifth. This technique enhances the density of the wood fibers. Lignin typically helps wood cells retain their structure and hinders compression. The reduced lignin content in genetically altered or chemically treated wood enables the cells to compress more tightly, strengthening the final product.
To further evaluate the efficiency of their genetically modified trees, the team also manufactured compressed wood from natural poplar, using both untreated wood and wood processed with conventional chemical methods to lower lignin content.
The results revealed that the compressed genetically modified poplar matched the performance of the chemically treated natural wood. Both achieved greater density and were over 1.5 times stronger than compressed untreated natural wood.
The tensile strength of the compressed genetically modified wood was comparable to aluminum alloy 6061 and the compressed chemically treated wood.
This research paves the way for generating a range of building products in a cost-effective, eco-friendly manner, potentially making a significant contribution to the fight against climate change.
