"Sweet crude" biofuel developed at University of Texas at Austin

By Chris Hanson | January 23, 2014

Researchers from the University of Texas at Austin developed “sweet crude” biofuel using genetically engineered yeast cells and household sugar. 

The yeast, a strain of Yarrowia Lipolytica, was genetically modified to enable up to 90 percent of the cell mass to become lipids, which was used to produce the biofuel.

“To put this in perspective, this lipid value is approaching the concentration seen in many industrial biochemical processes,” said Hal Alper, assistant professor at U.T. Austin’s Cockrell School of Engineering. He called the produced biofuel a “renewable version of sweet crude.”

Over the course of four years, the researchers were able to modify the yeast by removing and overexpressing specific genes that influenced lipid production. Furthermore, the team optimized culturing conditions that differ from the traditional method of tricking yeast cells into storing fat and materials through nitrogen starvation. “Our cells do not require that starvation,” Alper said. “That makes it extremely attractive from an industry production standpoint.”

“By genetically rewiring Yarrowia Lipolytica, Dr. Alper and his research group have created a near-commercial biocatalyst that produces high levels of bio-oils during carbohydrate fermentation,” said Lonnie Ingram, director of the Florida Center for Renewable Chemicals at Fuels at the University of Florida. “This is a remarkable demonstration of the power of metabolic engineering.”

At 90 percent lipid levels, the platform produced the highest lipid content levels created thus far using a genetically modified yeast cell. Other yeast-based methods yield 50 to 80 percent lipid content, but not always directly from sugar as the UT Austin method.

The Office of Naval Research Young Investigator Program, the DuPont Young Professor Grant and the Welsh Foundation funded the research at UT Austin.