UF Receives $1M to Unlock Energy from Sugarcane Residues

GAINESVILLE, Fla. — The University of Florida’s quest to develop cost-effective methods of producing fuel ethanol from biomass received a $1 million boost this month, with a grant package for research aimed at increasing the amount of fermentable sugar obtained from sugarcane stalks and leaves.

The three-year grant was announced March 4 by the Biomass Research and Development Initiative, a joint project from the U.S. Department of Energy and Department of Agriculture. Nearly $870,000 of the UF funding comes from the federal project. Another 20 percent, nearly $217,000, is from non-federal matching funds.

“What makes sugarcane an attractive target is, it produces a particularly large amount of biomass,” said project director Fredy Altpeter, an assistant professor of agronomy with UF’s Institute of Food and Agricultural Sciences.

The research team also includes three co-principal investigators, all from UF—Maria Gallo, an associate professor of agronomy; Wilfred Vermerris, an associate professor of agronomy; and James Preston, a professor of microbiology and cell science.

The researchers will use the funding to create genetically modified sugarcane varieties, Altpeter said. They aim to improve the quantity and accessibility of the crop’s hemicellulose, a complex carbohydrate that is one of the building blocks of plant cell walls.

Hemicellulose represents up to one-third of the material in sugarcane residues that could be used for biomass ethanol feedstock.

The research will focus on combinations of three transgenic improvements: altering the cell-wall composition so that hemicellulose can be separated more easily; causing the sugarcane to produce enzymes that will speed cell-wall breakdown during processing; and suppressing flower production.

The latter causes the sugarcane to devote more resources to biomass production, while also ensuring that the vegetatively propagated transgenic crop doesn’t produce seeds.

Gallo, who researches sugarcane biotechnology, said she’s particularly interested in methods of suppressing flowering.

“It’s a well-researched area in many other plants,” she said. “Now it’s just a matter of trying to get it to work in sugarcane.”

Preston will study the effect of genes from bacteria that will be transferred to sugarcane, causing the plant cells to produce enzymes that chemically break down hemicellulose into simple carbohydrates for efficient production of fuel ethanol. The enzymes would remain inactive while the crop grows, but could be activated after harvest to streamline processing.

“We have good candidate enzymes for expression in sugarcane,” Preston said. “Dr. Altpeter is going to be doing most of the work on this—he will develop technology to produce these enzymes at high quantities in transgenic sugarcane, co-introduce genes that modify cell-wall composition and confirm their value at a molecular level.”

Vermerris, who studies plant cell-wall biochemistry, will evaluate biomass from the transgenic sugarcane varieties the team develops to determine whether it can be processed more easily than standard varieties now in use.

“So it becomes an integrated project where you look at the physiology and chemistry,” he said.

“We expect to work all the way from generating plants with enhanced properties to conversion to bioethanol,” Altpeter said. “We want to do it on a laboratory scale first. But after the grant’s completed, the next step is demonstration in the field.”

In modifying the sugarcane, the researchers want to avoid reducing its sugar content. The result could be a dual-purpose crop—the juice could be used conventionally for sugar production; the leaves and crushed stalks, known as bagasse, could be processed to extract both cellulose and hemicellulose and break them down to yield simple carbohydrates used in ethanol production.

“Targeting efficient conversion of sugarcane residues to ethanol, reduces raw material costs, enhances productivity and sustainability,” Altpeter said.

Funds for the grant should be received shortly, with the project likely to begin in earnest in April, he said.

“We’re working on it already—we’ve made some gene constructs we’ll overexpress in sugarcane and started sugarcane tissue cultures,” Altpeter said. “Overall, we’re planning to evaluate 12 gene construct combinations and produce more than 250 transgenic sugarcane plants.”

Altpeter has been researching biotechnology in cereals, turf and forage grasses for more than 15 years. With the recent focus on bioenergy crops he wants to apply this knowledge to support the commercial production of biofuels at prices competitive with fossil fuels.

For More Information contact: Tom Nordlie, Science Communications Coordinator, External and Media Relations, Institute of Food and Agricultural Sciences, University of Florida, 2029 McCarty Hall D, P.O. Box 110275, Gainesville, FL 32611-0275; 352-392-0400 or Fax at 352-392-6931.