Purdue study separates corn stover, finds efficiency, savings

By Matt Soberg | November 01, 2011

Purdue University researchers found corn stover separation may increase efficiency for ethanol conversion and result in cost savings. Two studies, published in October in the journal of Biotechnology and Bioengineering, fractioned stover into leaves, rind and pith to determine which composition converts into sugars most efficiently. Stover, which is usually mixed and ground as a feedstock for processing, may perform better if divided into hard and soft materials. 

“Physical fractionation of corn stalks or other C4 grasses into soft and hard tissue types could reduce cost of cellulose conversion by enabling reduced enzyme loadings to hydrolyze soft tissue, and directing the hard tissue to other uses such as thermal processing, combustion, or recycle to the land from which the corn was harvested,” according to studies.

Trying to efficiently deconstruct the divided stover to convert cellulose into biofuels, the researchers “followed changes in the different structures during processing by pretreatment and enzyme hydrolysis,” said Nathan Mosier, associate professor of agricultural and biological engineering. As hypothesized, pith, the soft inner tissue of a corn stalk, produced the highest sugar yield. With pith being approximately 50 percent of stover composition, division before conversion makes a more efficient process, according to Eduardo Ximenes, research scientist in LORRE. In addition, harder stover materials, such as the rind, can be used for biomass combustion or other processes.  

The research has educated students on efficient conversion of cellulose to biofuels and enables them to carry out future work for the industry, added Michael Ladisch, professor of agricultural and biological engineering and director of Purdue’s Laboratory of Renewable Resources Engineering. 

Alongside Ladisch, Mosier and Ximenes, the research was led by Meijuan Zeng, doctoral graduate student and others. The research started approximately 10 years ago and was funded by the U.S. DOE, Purdue Agricultural Research Programs, and a David Ross Fellowship.