Beth Papanek,
working with nutrients for bacterial growth, and Adam Guss are among
the
ORNL authors of a paper published in Metabolic Engineering.
(August 15, 2015) Another
barrier to commercially viable biofuels from sources other than corn has fallen
with the engineering of a microbe that improves isobutanol yields by a factor
of 10.
The finding of the Department of Energy’s BioEnergy Science
Center, published in the journal Metabolic Engineering, builds on results from
2011 in which researchers reported on the first genetically engineered microbe
to produce isobutanol directly from cellulose.
Isobutanol is attractive because its energy density and
octane values are much closer to gasoline and it is useful not only as a direct
replacement for gasoline but also as a chemical feedstock for a variety of
products. For example, isobutanol can be chemically upgraded into a hydrocarbon
equivalent for jet fuel.
While the earlier work by BESC researchers at DOE’s Oak
Ridge National Laboratory and the University of California at Los Angeles was
important from a proof-of-principle perspective, this new result represents a
significant gain.
“When we reported our initial finding four years ago, we
were using Clostridium celluloyticium, which is a less complex organism from a
metabolic engineering perspective,” said co-author James Liao of UCLA’s Henry
Samueli School of Engineering and Applied Science. “With this paper, we have
successfully engineered similar traits in the much higher yielding Clostridium
thermocellum, and that has taken us to new levels of consolidated bioprocessing
efficiency.”