A
team of researchers at the Department of Energy’s BioEnergy Science
Center (BESC) have pinpointed the exact, single gene that controls
ethanol production capacity in a microorganism. This discovery could be
the missing link in developing biomass crops that produce higher
concentrations of ethanol at lower costs.
“The
Department of Energy relies on the scientific discoveries of its labs
and research centers to improve the production of clean energy sources,”
said Energy Secretary Steven Chu. “This discovery is an important step
in developing biomass crops that could increase yield of ethanol, lower
production costs and help reduce our reliance on imported oil.”
The
discovery of the gene controlling ethanol production in a microorganism
known as Clostridium thermocellum will mean that scientists can now
experiment with genetically altering biomass plants to produce more
ethanol. Current methods to make ethanol from a type of biomass found in
switchgrass and agricultural waste require the addition of expensive
enzymes to break down the plant’s barriers that guard energy-rich
sugars. Scientists, including those at BESC, have been working to
develop a more streamlined approach in which tailor-made microorganisms
produce their own enzymes that unlock the plant’s sugars and ferment
them into ethanol in a single step. Identifying this gene is a key step
towards making the first tailor-made microorganism that produces more
ethanol.
Although
scientists have studied Clostridium thermocellum for decades, the
genetic basis for its ability to tolerate higher concentrations of
ethanol had not been determined. Rather than using just one technique
or one approach, the research team that made the discovery was able to
draw upon multiple experts spanning several scientific disciplines to
contribute a broader set of analyses because of the BESC partnership.
BESC
is led by Oak Ridge National Laboratory and is one of three DOE
Bioenergy Research Centers established by the DOE’s Office of Science in
2007. The centers support multidisciplinary, multi-institutional
research teams pursuing the fundamental scientific breakthroughs needed
to make production of cellulosic biofuels, or biofuels from nonfood
plant fiber, cost-effective on a national scale.
The team’s results were published in the Proceedings of the National Academy of Sciences. The invention is available for licensing.
Mutant alcohol dehydrogenase leads to improved ethanol tolerance in Clostridium thermocellum
