CAMBRIDGE, England, Dec. 21 (UPI) -- Scientists have discovered the secret to the strength of cell walls and the adhesive qualities of cellulose and xylan, two of nature's largest molecules. The discovery could inspire wooden skyscrapers and more sustainable paper production processes.
Cellulose and xylan are large, long molecules that give wood and straw their strength. They're also very hard to digest. Scientists knew the two molecules stick together inside the cell walls of plants, but had, until now, failed to figure out how.
"We knew the answer must be elegant and simple," lead researcher Paul Dupree, a professor of biochemistry at the University of Cambridge, said in a news release. "And in fact, it was."
"What we found was that cellulose induces xylan to untwist itself and straighten out, allowing it to attach itself to the cellulose molecule," Dupree explained. "It then acts as a kind of 'glue' that can protect cellulose or bind the molecules together, making very strong structures."
Scientists imaged the two molecules using solid state nuclear magnetic resonance. The technology is similar to hospital MRI scanners but requires carbon-13, a heavy carbon isotope. Scientists met the requirement by growing plants in an atmosphere rich in carbon-13 dioxide. The high-resolution imaging revealed the unique structures of the two molecules at nanoscale.
"By studying these molecules, which are over 10,000 times narrower than the width of a human hair, we could see for the first time how cellulose and xylan slot together and why this makes for such strong cell walls," said Ray Dupree, Paul's father and a researcher at the University of Warwick.
The discovery could help scientists make wood strong enough to support skyscrapers. The research could also help break down the two molecules.
"One of the biggest barriers to 'digesting' plants -- whether that's for use as biofuels or as animal feed, for example -- has been breaking down the tough cellular walls," Paul Dupree said. "Take paper production -- enormous amounts of energy are required for this process. A better understanding of the relationship between cellulose and xylan could help us vastly reduce the amount of energy required for such processes."
The new research was published in the Nature Communications.