Cellulosic Ethanol: Expanding Options, Identifying
By Ann Perry
April 9, 2010
Agricultural Research Service (ARS)
scientists are figuring out how to turn wheat straw into ethanol
gold, and learning more about the bacteria that can
infect ethanol plants and interfere with fuel production.
At the ARS
Center for Agricultural Utilization Research (NCAUR) in Peoria, Ill., ARS
Saha conducted a 5-year study that examined whether wheat strawa crop
residue left over after the grain has been harvestedcould have commercial
potential for cellulosic ethanol production.
Saha found he could access and ferment almost all the plant sugars in the
biofeedstock when it was pretreated with alkaline peroxide and then broken down
by enzymes. This process released even hard-to-reach sugars in plant cell
walls, which significantly boosted the overall ethanol output to around 93
gallons per ton of wheat straw.
But the same environments that facilitate fermentation can also nurture
microorganisms that infect ethanol production facilities and
disrupt output. ARS geneticist
Leathers collected bacteria from samples at commercial ethanol facilities,
including a wet-mill facility that had never been dosed with antibiotics and a
dry-grind facility that periodically dosed with antibiotics after bacterial
outbreaks. He found that most of the bacterial isolates he collected from both
facilities were different types of lactic acid bacteria.
Meanwhile, ARS microbiologist
Bischoff developed a model for simulating bacterial contamination and
infection. He found that when test cultures were inoculated with
Lactobacillus fermentumone of the most common sources of bacterial
infections in ethanol plantsethanol yields decreased by 27 percent.
Sometimes the infection could be cured with antibiotics, but he
also found one bacterial strain that was already resistant to treatment.
Results from this research have been published in several journals,
and Bioengineering, the Journal of Biobased Materials and
Bioenergy, and the Journal of Industrial
Microbiology and Biotechnology.
more about this research in the April 2010 issue of Agricultural
ARS is the principal intramural scientific research agency of the
U.S. Department of Agriculture (USDA). This
research supports the USDA priority of developing new sources of bioenergy.