Michigan State University (MSU) has patented a process to pretreat agricultural waste products that would dramatically reduce the cost of making biofuels from cellulose.

According to a university release, The AFEX (ammonia fiber expansion) pretreatment process, developed by MSU chemical engineering professor Bruce Dale, uses ammonia to make the breakdown of cellulose and hemicellulose in plants 75 percent more efficient than when conventional enzymes alone are used. Cellulose in plants must be broken down into fermentable sugars before they can be turned into biofuel.

Currently, pretreating cellulose with acid is a common way to break the material down into fermentable sugars. But after acid pretreatment, the resulting material must be washed and detoxified. That removes nutrients, leading to the mistaken idea that crop waste lacks the necessary nutrients, Dale said. Cellulosic material pretreated with the AFEX process doesn’t have to be washed or detoxified, allowing ethanol to be created from cellulose without added nutrients or other steps.

The next step for the patented process could be a pilot plant to commercialize technology. “There are several companies – including the Mascoma Corp., which plans to open one of the nation’s first cellulosic ethanol plants here in Michigan – that may be interested in using this technology,” Dale said. “We are working to make the AFEX technology fit these companies’ needs.”

Dale is associate director of the MSU Office of Biobased Technologies and has a leadership role in the Great Lakes Bioenergy Research Center. The center is a partnership between Michigan State and the University of Wisconsin-Madison, funded by the U.S. Department of Energy, to conduct basic research aimed at solving some of the most complex problems in converting natural materials to energy. The research is published in the current issue of the Proceedings of the National Academy of Sciences.