Building block of plants: Lignin is seen here stained red in a cross-section of plant cells from an oak tree. Source: Berkshire Community College Bioscience Image Library

Researchers from the U.S. Department of Energy’s National Renewable Energy Lab (NREL), Montana State University and the University of California Los Angeles have discovered a new family of enzymes that can convert plant waste into eco-friendly and high-value products. These products include nylon, plastics, chemicals, fuels and more.

The new enzymes are active on the building blocks of lignin. Lignin is one of the main chemicals in plants and is the scaffolding and one of the key parts of water delivery throughout plants. Research teams in the past have attempted to break down plant lignin, but it has proven difficult until the new enzyme was developed.

"To protect their sugar-containing cellulose, plants have evolved a fascinatingly complicated material called lignin that only a small selection of fungi and bacteria can tackle. However, lignin represents a vast potential source of sustainable chemicals, so if we can find a way to extract and use those building blocks, we can create great things. It's an amazing material," said Professor McGeehan, director of the Institute of Biological and Biomedical Sciences in the School of Biological Sciences at Portsmouth. "Cellulose and lignin are among the most abundant biopolymers on earth. The success of plants is largely due to the clever mixture of these polymers to create lignocellulose, a material that is challenging to digest."

The research team has found a way to release the bottleneck of lignin with the enzymes. By releasing the bottleneck, the lignin is turned into basic chemicals that are much easier to break down and use to create new materials.

This discovery has many environmental benefits. With the new process, products can be created from lignin, which reduces the manufacturing industry’s reliance on oil to create everyday products. By using lignin to create products, CO_₂ emissions are greatly reduced.

Sam Mallinson, a Ph.D. student in structural biology at the University of Portsmouth and first author on the paper, said, "There is a long-standing phrase — you can make anything out of lignin except money — but by harnessing the power of enzymes, this is set to change. Using advanced techniques, from X-ray crystallography at the Diamond Light Source synchrotron, to advanced computer modeling; we have been able to understand the detailed workings of a brand new enzyme system."

The enzyme is part of a new class of cytochrome P450, which can work on a wide range of molecules.

The paper on the new enzyme was published in Nature Communications.