Governors' Biofuels Coalition

Researchers from North Carolina State University have figured out how to map a three-dimensional model of a key plant enzyme, a discovery that they hope will help scientists genetically engineer better biofuel crops.

The researchers created the image of an enzyme that is able to link simple sugars into a chain of cellulose, the tough material that provides structure in plants and the most abundant biomaterial found on Earth.

The findings, published last week in the Proceedings of the National Academy of Sciences, are being hailed as groundbreaking, as they represents the first time that a cellulose-creating enzyme has been put into 3-D form. Scientists say they will be able to use the model made from the enzyme found in cotton fibers to study other plants and create crops suited for biofuels and other uses.

“This structural model gives us insight into how cellulose synthesis works,” said Yaroslava Yingling, a materials science and engineering professor at North Carolina State and a co-author of the study. “In the long term, it could result in new genetically modified plants that can be tweaked to induce specific engineered properties of cellulose.”

The authors say having the enzyme structure available in a readable 3-D form, for example, could help them engineer new versions of plants in which the cellulose is easier to break down.

In the production of advanced biofuels from feedstocks such as switch grass and agricultural residues, the first step is often a harsh pretreatment process that decomposes the cellulose into its component sugars. The sugars are then processed into fuels through fermentation or other methods. Scientists have been actively searching for ways to engineer plants with less cellulose or cellulose that can be broken down more easily.

“Without the enzyme structure, you can’t make strategically designed, rational projections about how to make beneficial changes to proteins — but now you can,” said Candace Haigler, a North Carolina State University crop scientist and plant biologist, and a co-author of the study. “In the future, we could make cellulose easier to break down into biofuels while ensuring that the plants themselves are able to grow well.”

Along with creating better biofuels, the researchers say it may also allow them to genetically engineer trees with stronger wood.

The study was completed with help from Penn State University, the University of Virginia, the University of Ontario Institute of Technology and the University of Kentucky. The Center for LignoCellulose Structure and Formation, a Department of Energy research center, provided funding.

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