Researchers at MIT used engineered yeast to produce alcohol in the mitochondria. The mitochondria produce the energy in the cell, making them more efficient.
Yeast has been used over millennia for two basic purposes, bread and alcohol, both of which keep the belly full and the heart happy. Hopefully not too full and not too happy, though, since we’ve got responsibilities in the morning, like reducing carbon dioxide emissions.
Yeast is a special fungus which consumes sugar and gives off alcohol as a waste product. One type of alcohol, specifically ethanol, is also a great fuel. The first Ford Model T’s ran on ethanol and got about 25mpg, and that was in 1908.
The source of that ethanol, yeast, typically only produces it in small quantities. Such a process was a good fuel back a century ago, but then, there weren’t nearly as many vehicles on the road. Fossil fuels such as gasoline and diesel, being more abundant, served as a quick and dirty replacement for ethanol. The fuel supply here in the US today is universally blended with 10% ethanol to reduce emissions. Specially designed flex-fuel vehicles can run on E85, 85% ethanol, blend.
Yeast also emits other alcohols such as isobutanol, isopentanol, and 2-methyl-1-butanol, which are even better fuels. These are produced naturally in small quantities, and could be industrialized to replace gasoline completely, if we could just get microscopic yeast to increase output.
To that end, chemical engineers at the Massachusetts Institute of Technology [MIT] have been working with yeast strains, engineering them to produce alcohol in the mitochondria. The mitochondria produce the energy in the cell, making them more efficient.
By changing the location of the alcohol synthesis in the engineered yeast, MIT chemical engineers were able to boost isobutanol production by 260%, isopentanol by 370%, and 2-methyl-1-butanol by 500%. Even though this is only on a small scale, scaling yeast alcohol production should be successful. Alcohol, of course, is still a hydrocarbon fuel emitting carbon dioxide on combustion, but also reduces the dependency on petroleum imports and their sometimes disastrous extraction techniques.