Texas researcher looks into biodiesel production from lignin

By Holly Jessen | January 17, 2013

A two-year research project aims to crack the lignin question by engineering a microbe to break down the byproduct into a lipid, or fat, and then into biodiesel. The research has the potential to make cellulosic ethanol refineries more profitable.

“According to one of my calculations, if all of the lignin produced from cellulosic ethanol [was] used for biodiesel, a conservative estimation is that 1.8 billion gallon of biodiesel can be produced,” Joshua Yuan, a Texas A&M University AgriLife Research plant pathologist and lead researcher on the project, told Ethanol Producer Magazine, adding that it has the potential to contribute about 10 percent of total advanced biofuel production.

The project was recently awarded $2.4 million by the U.S. DOE. Besides Yuan, the team is made up of scientists from Georgia Institute of Technology, University of British Columbia and Washington State University.

According to the International Lignin Institute, headquartered in Switzerland, about 50 million tons of lignin are produced worldwide every year, including by the paper industry. “There are several things to understand about lignin. It’s resistant to degradation and very strong,” Yuan said. “It can be burned, but there is so much that burning all of it would create an environmental hazard.”

A cellulosic ethanol biorefinery would produce about 60 percent excess lignin, Yuan said. The research is expected to result in methods to convert at least 40 percent of that. “Probably one of the most important challenges a biomass refinery faces today is how to use lignin. We need a profitable way to use it,” he said. “What we propose is to transform these huge amounts of hazardous waste into a huge amount of oil that will be useful for us.”

Researchers will test lignin they will produce themselves as well as some sourced from industry collaborators. That includes a paper mill and a lignocellulosic refinery, he said.

Currently, researchers can’t predict when the project will yield marketable results; however, Yuan can see a future where it could lead to commercial biodiesel production from lignin. Another grant proposal is pending with the DOE to complete a techno-economic and life cycle analysis of lignin-to-biodiesel, important factors in commercialization, Yuan said.