Engineered for tolerance, bacteria pump out higher quantity of renewable gasoline

An international team of bioengineers has boosted the ability of bacteria to produce isopentenol, a compound with desirable gasoline properties. 

The finding, published in mBio®, the online open-access journal of the American Society for Microbiology, is a significant step toward developing a bacterial strain that can yield industrial quantities of renewable bio-gasoline.

The metabolic engineering steps to produce short-chain alcohol solvents like isopentenol in the laboratory bacteria Escherichia coli have been worked on extensively by many research groups, explains Aindrila Mukhopadhyay, director of host engineering at the Joint BioEnergy Institute in Emeryville, California and senior author on the study.

"Biofuels are one tool in the array of alternative energy solutions that can be used in our infrastructure immediately," she says. Sustainably produced fuel compounds can be added directly into gasoline blends used today to offset reliance on fossil fuels and also lower the net carbon emissions from vehicles.

"But the solvent-like compounds inhibit microbial growth and that was an aspect that we realized would come up sooner rather than later," says Mukhopadhyay, who holds a joint appointment at Lawrence Berkeley National Laboratory. "We wanted to look at that aspect with a systems biology approach -- could we engineer bacteria to also tolerate the solvent it is producing?" Improving tolerance is key to moving production toward levels that are industrially relevant.