A scientist with Texas A&M AgriLife Research has begun work on a way to "engineer" a microbe to break lignin into lipid which can then be used to make more fuel.
The project, which received a $2.4 million grant from the U.S. Department of Energy, could help solve the challenge of biowaste generated in biofuel production, according to Dr. Joshua Yuan of College Station, AgriLife Research plant pathologist and lead researcher on the project.
"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," Yuan 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."
Dr. Joshua Yuan, Texas AgriLife Research plant pathologist
Lignin is what is left after the sugar, or cellulose, in a plant has been converted into ethanol, he explained.
About 50 million tons of lignin are produced every year worldwide and mostly as non-commercialized waste, according to the International Lignin Institute, headquartered in Switzerland.
"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."
Modern biorefineries for cellulosic ethanol have 60 percent excess lignin, he said.
Because of its tough structure, Yuan said, his team began considering ways to use engineering technology to design biological processes - commonly referred to as synthetic biology - to help discover ways to convert lignin.
That led them to the microorganisms in the Rhodococcus genus that have the potential to be improved genetically in order to turn lignin into lipids, or fats, which can be used to produce biodiesel.
Yuan said the project is expected to result in a way to convert at least 40 percent of processed lignin.
"The conversion will allow more complete use of carbon in biomass and result in the mitigation of more than 20 million tons of carbon dioxide," Yuan said. "It will also provide another major type of feedstock for biodiesel production, potentially contributing about 10 percent of the total advanced biofuel production.
"The lignin-to-fuel platform would also simplify waste treatment and make refineries more profitable."
The researchers do not have a prediction for when the research will yield marketable results, but Yuan envisions a time when refineries will be able to purchase the newly developed microbes to degrade lignin into a substance usable for fuel production.
On the project with Yuan are Arthur Ragauskas, Georgia Tech University; Lindsay Eltis and William Mohn, University of British Columbia; Bin Yang, Washington State University; and Susie Dai, Texas A&M University.