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Turning cellulose into biofuel: VU prof, grad student search for key on molecular level

Sonia Brady, a Ph.D. candidate in chemical engineering, at work in the Lang Laboratory. (Susan Urmy/Vanderbilt University)

Nature exquisitely engineered a way to produce fuel from organic matter. The answer to how lies in decaying leaves on the forest floor or a backyard compost pile and the tiny amounts of energy those produce.

Without understanding how enzymes are working to break down organic matter on the molecular level, human engineers can’t apply the process to untold areas of research, including the significant promise of efficient and plentiful biofuels.

Matt Lang, professor of chemical and biomolecular engineering, and Sonia Brady, a Ph.D. candidate in chemical engineering, are beginning to decode the process.

Lang studied motor proteins before coming to Vanderbilt University from MIT, often in the context of medical applications — areas such as cell division or protein degradation. When he arrived, faculty at Vanderbilt introduced him to cellobiohydrolase enzymes and how they break down cellulose, the most abundant organic polymer on Earth.

Through cross-disciplinary collaborations, Lang and Brady were able to take that process down to a single-molecule assay.

Brady, left, and Matt Lang, professor of chemical and biomolecular engineering at Vanderbilt University. (Susan Urmy/Vanderbilt University)

“We now have a way to watch individual cellulase motors and how they move,” Lang said. “How fast do they move at elevated temperatures? How fast do they move in different environmental conditions? How much force do they exert? When do they stall?”

Traditional research involved applying bulk sets of enzymes to cellulose, making it impossible to know specifically how they were breaking it down to basic sugars. Without that information, how to develop biofuels from cellulose would remain a mystery.

Ethanol, derived from corn, provides a good context to explain Lang and Brady’s research. It’s simple to make because it converts starch in the corn itself into fuel. Brady and Lang want to break down cellulose in the corn husks — or from other feedstocks that can be grown more quickly and pull fewer nutrients from the soil than corn.

“It’s a big issue. Our part is like this,” Brady said, holding her hands almost together.

Brady, who credits her father’s work in the oil industry with her interest in alternative fuel sources, arrived at Vanderbilt in the fall of 2011 from Trinity University in San Antonio. She won the Department of Chemical and Biomolecular Engineering’s teaching assistant award her first year.

Brady began working in the Lang Laboratory in 2012 and, in order to do the research she and Lang envisioned, needed to stretch well beyond her chemical engineering background. Vanderbilt’s strong culture of cross-institutional collaboration gave her that opportunity.

“Nobody goes into their lab knowing exactly what they’re going to do,” she said. “A lot of it is on-the-job training. I’ve learned so much from Matt on the optics and assay development side and from other students in the school – asking about biology or borrowing an instrument from another department. We certainly have collaborators across campus.”


Heidi Hall, (615) 322-6614
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