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A collaborative research project between the U.S. Forest Service Forest
Products Laboratory (FPL) and the Department of Energy Joint Genome
Institute has advanced the quest for efficient conversion of plant biomass
to fuels and chemicals, March 2007.

"We have sequenced and assembled the complete genome of Pichia stipitis, a
native xylose-fermenting yeast," says Thomas Jeffries, research
microbiologist at FPL and a professor of bacteriology at the University of
Wisconsin-Madison. The results of this research project will be published in
the scientific journal Nature Biotechnology in April, and the report is
currently available online.

The sequencing of P. stipitis marks an important step toward the efficient
production of biofuels because the yeast can efficiently ferment xylose, a
main component of plant lignocellulose. Xylose fermentation is vital to
economically converting plant biomass to fuels and chemicals such as
ethanol.

"A better understanding of the genetic structure of this yeast allows us to
determine how specific genes are used in fermentation and then reengineer
them to perform other desired functions," says Jeffries.

For example, Jeffries explains that the fermentation of both glucose and
xylose is critical to efficient bioconversion because xylose is so abundant
in hardwoods and agricultural residues. However, when glucose is present,
the fermentation of xylose by P. stipitis is repressed. Using their
knowledge of the genetic makeup of the yeast, researchers will be able to
alter the expression of the genes so that both glucose and xylose are
fermented simultaneously. This will increase the efficiency, and improve the
economic viability, of the process.

The U.S. Forest Service Forest Products Laboratory, with its mission to
conserve and extend the country's wood resources, is a partner in the
Wisconsin Bioenergy Initiative, an effort launched by the UW-Madison College
of Agricultural and Life Sciences to accelerate the development of bioenergy
resources. FPL scientists have been studying P. stipitis for 20 years and in
that time have isolated and characterized several genes, developed improved
strains, and recently licensed technology to a biotech firm for commercial
development.

"We are very proud of Tom's research and the breakthroughs he and his
colleagues continue to make," says FPL Directory Chris Risbrudt.
"Publication in a journal of such importance to the scientific community
demonstrates the capability of FPL's researchers and our status as a
world-class facility."

"The genetic blueprint reported in this paper will be at the foundation of
new biofuels technology that will be developed under the auspices of the
Wisconsin Bioenergy Initiative," reports Tim Donohue, professor of
bacteriology. "It will have benefits in making ethanol production from plant
sugars more efficient in the short term and it is likely to help develop
long-term bioenergy solutions that help Wisconsin assume a position of
leadership in the rapidly growing biofuels economy."

[www.news.wisc.edu]