Berkeley Laboratory Develops a New Way to Reduce Plant Lignin

Scientists from the US Department of Energy's Lawrence Berkeley National Laboratory have shown that an enzyme can be tweaked to reduce lignin in plants. Their technique could help lower the cost of producing biofuels and other bio-products.

Lignin is an important polymer to a plant's health and structure, but also is present in cell walls and traps sugars inside. This is a major challenge for microbes to ferment the sugar into useful chemicals and fuels, prompting for a costly pre-treatment step before fermentation.

They focused on an enzyme, HCT, which plays a key role in synthesizing lignin in plants. HCT binds with a particular molecule as part of the lignin-production process. The scientists studied the enzyme and found out that HCT binds with other molecules with similar structures as the original molecule.

Researchers then introduced another molecule to the enzyme that occupies the binding site usually occupied by the lignin-producing molecule. This swap inhibits the enzyme's ability to support lignin production.

Initial tests show that this approach decreases lignin content by 30% while upping sugar production. The technique also promises to be much more "tunable" than the current way of reducing plant lignin, in which lignin-producing genes are silenced. The current way decreases lignin everywhere in the plant and throughout its lifespan, resulting in a weak plant and a lower sugar yield.