New Method Transforms Crop Waste into Valuable Chemicals to Replace Petroleum

Imagine taking waste from crops and, instead of throwing it away, turning it into something useful. Scientists are doing just that with a new technique. They found a way to convert lignin, a biomass waste product, into simple and valuable chemicals that could be used for other applications.

Lignin is the substance that makes trees and cornstalks sturdy. It accounts for nearly 30 percent of organic carbon in the biosphere. It contains chains of six-carbon rings; these rings, called "aromatics," could potentially be the basis for a sustainable supply of useful chemicals.

"Aromatics are used to make many things, from plastic soda bottles to Kevlar to pesticides and pharmaceuticals," said Shannon Stahl, the senior author of the new paper, in a news release. "Today, the aromatics are almost exclusively derived from petroleum. We need to find an economical way to convert lignin to value-added materials."

In this case, the scientists found that if they exposed lignin to oxygen followed by treating it with a weak acid under mild conditions, they obtained high yields of aromatics. This method to break down the lignin could eventually lead to the creation of chemicals.

"The oxidation step weakens the links in the lignin chains," said Alirez Rahimi, first author of the new study. "The acid then breaks the links."

The fact that the researchers can now break down lignin is a huge step forward when it comes to creating valuable materials. That said, chemicals obtained from this process will still require further manipulation before they have real market value. Yet this is a good step in the right direction.

The findings are important for creating a sustainable replacement for petroleum in petroleum-based products. Lignin represents a material that could be utilized in multiple ways in the future.

The findings are published in the journal Nature.