In the search for renewable alternatives to gasoline, heavy
alcohols such as isobutanol are promising candidates. Not only
do they contain more energy than ethanol, but they are also more
compatible with existing gasoline-based infrastructure. For
isobutanol to become practical, however, scientists need a way
to reliably produce huge quantities of it from renewable
sources. MIT chemical engineers and biologists have now devised
a way to dramatically boost isobutanol production in yeast,
which naturally make it in small amounts. They engineered yeast
so that isobutanol synthesis takes place entirely within
mitochondria, cell structures that generate energy and also host
many biosynthetic pathways. Using this approach, they were able
to boost isobutanol production by about 260 percent. Though
still short of the scale needed for industrial production, the
advance suggests that this is a promising approach to
engineering not only isobutanol but other useful chemicals as
well, says Gregory Stephanopoulos, an MIT p