Plant cells may increase ethanol yields.

• Position: Green Fuels

Particles from cornstalks undergo what previously were unknown structural changes when processed to produce ethanol, an insight researchers say will help establish a viable method for large-scale production of ethanol from plant matter. It has been demonstrated that pretreating corn plant tissue with hot water--an accepted practice that increases ethanol yields three to four times--works by exposing the minute pores of the plant's cell walls, thus increasing surface area for additional reactions that help break down the cell wall.

"This brings together the tools that link the processing technology to the plant tissue physiology," explains Nathan Mosier, assistant professor of agricultural and biological engineering at Purdue University, West Lafayette, Ind. "It helps us understand, on a fundamental level, what the processing is doing and how we can improve it."

Using high-resolution imaging and chemical analyses, the researchers determined that pretreatment opens reactive areas within the cells of the corn stover--another name for postharvest corn remnants, like leaves and stalks--that previously had been overlooked. In the next step of processing, these enlarged pores more easily are attached by enzymes that convert cellulose into glucose, which, in turn, is fermented into ethanol by...