A team of researchers headed by an environmental engineer at
Washington University in St. Louis is plying new techniques to produce
a biofuel superior to ethanol.
The fuel is butanol, It can be derived from lignocellulosic
material, plant biomass parts that range from woody stems, straw,
agricultural residues, corn fiber and husks, all containing in large
part cellulose and some lignin.
Butanol is considered to be a better biofuel than ethanol because
it’s less corrosive and has a higher caloric value, giving a higher
energy value. Like ethanol, butanol is being considered as an additive
Lars Angenent, Ph.D., Washington University assistant professor of
energy, environmental and chemical engineering, takes pre–treated corn
fiber , a byproduct of corn-to-ethanol production, from his
collaborators at the United States
Department of Agricultural (USDA) research facility in Peoria, Ill.,
and places the lignocellulosic biomass into digesters comprised of a
selected mixed culture of thousands of different microbes to convert
the biomass into butyrate.
From there the material is sent back to Peoria where another
collaborator, Nasib Qureshi. Ph.D., using fermenters, converts the
butyrate to butanol.
The USDA researchers Bruce Dien, Ph.D., and Michael Cotta, Ph.D.
use physical and chemical techniques to make the hard-to-degrade
lignocellulosic material more amenable to degrade, an important step
that allows Angenent’s mixed media culture to work its magic.
He uses a mixed culture containing thousands of different
microorganisms and optimizes environmental conditions to select for a
bacterial community that makes an environment conducive to the
conversion of the corn fiber to butyrate.
Mixed culture magic
“The thrust of my lab is the use of mixed cultures,” said Angenent.
“The advantage of mixed cultures is that it can take just about any
waste material, and through our manipulations, convert it into
something valuable. For instance, I can alter the pH in this culture .
By keeping it neutral, I can get methane gas, but when I lower the pH,
I can get butyrate. If I have a pure culture, on the other hand, I have
to worry about other organisms slipping in and altering or
contaminating the environment.
“Lignocellulosic biomass is plentiful, renewable, and a good way to
deal with wastes. By using it, we open the door for better economic
opportunities for crop producers and rural communities. And because
this kind of biomass is carbon-neutral, we don’t worry about carbon
dioxide being released into the atmosphere”
Using microbial fuel cells and his mixed media cultures, Angenent
in recent years has produced electricity or hydrogen in the process of
He is the principal investigator of a USDA grant for $425,000 on this research, with his co-P.I.s from USDA.
There is a butanol bandwagon that is growing. In 2006, chemical
maker DuPont and the British oil company BP announced collaboration
with British Sugar to introduce butanol made from sugar beets as a
gasoline-blending additive in the United Kingdom.
Source : Washington University in St. Louis. January 16, 2008.