Breaking Down the Wall to Cellulose

If we understand how cellulose and plant cell walls are made, we can manipulate them for human benefit.

Humans have used plants to feed, clothe, house and warm themselves for millennia. Yet, scientists know very little about how plants build the cell walls that have become food, textiles, lumber and fuel for mankind. “We have been using plant cell walls as a renewable source of materials since before we organized ourselves into civilizations. It’s what nature gave us to work with,” says Dr. Candace Haigler, a professor in the departments of Crop Science and Plant Biology. “But the fundamental science behind them, that’s still a mystery.”

Haigler is associate director of the Center for Lignocellulose Structure and Formation (CLSF), funded with a five-year Recovery Act grant through the U.S. Department of Energy, with research by NC State, Penn State and Virginia Tech. The center’s primary functions are to understand how cellulose is made, pinpoint interactions between molecules involved in plant cell-wall assembly, and determine how the assembled wall underpins physical properties important to industry. Dr. Alex Smirnov, a professor in the Department of Chemistry, and Dr. Yaroslava Yingling, an assistant professor in the Department of Materials Science Engineering, are working with Haigler. Their $2.8 million portion of the grant allowed them to hire three researchers and pay graduate and undergraduate students to assist with the effort.

Haigler identifies the proteins in cellulose synthesis through a complex process in which she freezes plant cells in liquid propane and cleaves them so interior features — including membrane proteins that synthesize cellulose — can be seen by a transmission electron microscope. Meanwhile, Yingling has developed a theoretical model of an enzyme that plays a key role in synthesis of cellulose fibers. The model depicts the way the enzyme folds, which is important to understanding how it functions. Smirnov is providing experimental data to test Yingling’s model, and also is studying the behavior and interaction of fragments of plant proteins that he has inserted into layers of lipids to mimic a cell’s plasma membrane.

The NC State researchers are relaying their findings to CLSF colleagues tackling the center’s other areas of study. “The way cellulose is synthesized is being revealed to us,” Haigler says, noting the composite structures of cell walls provide plants with strength, flexibility and rigidity, which has implications for the strength of lumber, ease of creating paper or fuels, or characteristics of textiles. “If we understand how cellulose and plant cell walls are made, we can manipulate them for human benefit or improve synthetic materials through introducing properties found in natural materials.”

 

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Dr. Candace Haigler’s cellulose research has implications for lumber, paper, fuel and textile industries.