Brookhaven National Laboratory researchers modify grass plants for easier bioenergy conversion

In New York state, plant biologists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have engineered enzymes to modify grass plants so their biomass can be more efficiently converted into biofuels and other bioproducts. As described in a paper just published in Plant Biotechnology Journal, these enzymes modify molecules that make up plant cell walls to provide access to fuel-generating sugars normally locked within complex structures.

In prior work, researchers successfully expressed engineered enzymes called monolignol 4-O-methyltransferases (MOMTs) in poplar trees. These enzymes reduced the trees’ lignin content and enabled more abundant sugar release from the plants. In the new research, they tested the potential applications of the MOMT enzymes in grass plants, which have an abundant biomass yield. Grasses can also grow in harsh environments, such as on soils deficient in water or nutrients. Cultivating engineered plants in such environments could potentially produce large amounts of biomass optimized for conversion to fuel and bioproducts—without competing for land needed to produce food crops.

With less lignin in the cell walls, the scientists were able to collect up to 30% more sugar from plants expressing MOMT4 and up to 15% more sugar in plants expressing MOMT9, compared to unaltered plants. Through a process called fermentation, this sugar can be converted into biofuels like ethanol, which is a common additive used to lower the fossil fuel content of gasoline.

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