Better bugs for brewing butanol

US researchers have developed a new way of hijacking microbe metabolism to produce long-chain alcohol fuels which are better petrol substitutes than ethanol.

Jim Liao and colleagues from the University of California, Los Angeles, re-engineered the Escherichia coli bacterium to force it to produce isobutanol and a variety of other promising long-chain alcohol fuels.

Butanol and branched-chain related alcohols with four or five carbon atoms are far superior to ethanol as petrol substitutes. They store more energy per litre (though still not as much as petrol); they suck up less water from the atmosphere, so are less prone to contamination; and they are less corrosive to pipelines than ethanol.

Since 1916, it's been known that microbes such as Clostridium acetobutylicum can ferment sugar to produce butanol and ethanol, but the process can't compete with cheaper techniques based on petroleum distillation. Now, as the price of oil increases, bugs are back in favour, yet butanol fermentation is still not economically viable.

Read the full story