North Carolina State University scientists report developing a simple, effective and relatively inexpensive technique that may reduce biofuel production costs.

The technique involves removing lignin from plant material "biomass" that serves as a feedstock for biofuels.

Lignin, which protects plant cell walls, is difficult to break down or remove from biomass such as the non-edible parts of the corn plant. The lignin needs to be extracted to reach the energy-rich cellulose used to make biofuels, the researchers said.

"Finding inexpensive ways to remove lignin is one of the largest barriers to producing cost-effective biofuels," chemical and biomolecular engineering doctoral student Ezinne Achinivu said. "And our approach is very promising."

The researchers' technique makes use of a number of inexpensive-to-create liquid salts called "protic ionic liquids" that are mixed with biomass, and then heated and stirred.

The lignin dissolves into the liquids, leaving the cellulose behind as a solid. The solid is easier to process, and by filtering it from the mixture it is ready for use in the next biofuel production steps.

"This PIL-based technique can be easily scaled up and is likely to be both more energy efficient and less expensive than existing biomass pretreatment techniques for removing lignin," Achinivu said.