Single Microbe Yields Ethanol, Plus Eco-Friendly
By Erin Peabody
April 12, 2007
Squeezing more ethanol from
cellulosethe basic material from which all plants are madeis still
a lofty goal for scientists. The process uses expensive enzymes that are
limited in their ability to convert stubbornly rigid plant cells walls into
Now, an Agricultural Research Service (ARS) microbiologist has discovered a way to
boost cellulosic ethanol production, with the help of some unusually hardy
Weimer, who works at the agency's
Dairy Forage Research Center in Madison, Wis., is tapping the
plant-degrading powers of Clostridium thermocellum. Thanks to this
heat-loving microbe, which thrives in 145-degree-Fahrenheit environments and
doesn't require oxygen, he's been able to create not only ethanol, but an
all-natural wood glue as well.
According to Weimer, this bioadhesive could be a marketable byproduct of
cellulosic ethanol production. It represents an added value and a means of
potentially offsetting the high costs that currently inhibit the commercial
production of cellulose-based fuel in the United States.
Even better is that Weimer's method relies on a potentially cheaper, more
streamlined ethanol-making process called consolidated bioprocessing. Instead
of using two reactors, enzymes, plus yeastas standard cellulosic ethanol
production requiresthis approach uses only one reactor and a single
industrious microbe that makes its own enzymes.
The idea for a bioadhesive came to Weimer while observing Clostridium
bacteria under a microscope breaking down bits of alfalfa. He saw that during
the conversion of plant fiber ethanol, the bacteria latched onto the fiber with
such fierceness that the only way to break the bond was to destroy the microbes
and their sticky adhesive.
With scientists at the USDA Forest
Service's Forest Products
Laboratory in Madison, Weimer has found that this bioadhesive is tough
enough to replace up to 70 percent of the petroleum-based phenol-formaldehyde
that's used to manufacture plywood and other pressed-wood products.
more about this research in the April issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's chief scientific research agency.