Scientists have found that it is possible to alter the genetic makeup of the bacterium E. coli to and induce it to produce biodiesel. Most microbes, including E. coli, make and process fatty acids, one of the ingredients of biodiesel; however, what they do with it often leaves something to be desired when it comes to fuel production. By modifying E. coli, scientists are able to make it produce fatty esters, which are the primary components of biodiesel.

Engineering bacteria to do a scientist's bidding is a good way to obtain desired materials, such as natural compounds for drugs, or in this case, fuels. Since E. coli is a well known and often-studied microorganism, and is able to produce fatty acids before any alteration, it is an excellent workhorse for synthetic biology.

The changes performed here include removing the enzymes involved in some competing pathways in order to enhance fatty acid production. Additional pathways were added in to convert those fatty acids to fatty esters, which make for better biofuel material. Finally, enzymes that break down the cellulose in plant matter were added in, allowing the E. coli to work directly on biomass.

The altered E. coli can receive various inputs, including partially processed material like glucose and ethanol, and produce fatty acid methyl esters, or biodiesel. The bacteria also produce some fatty alcohols, waxes, and simple sugars that may be harvested and used for other purposes. The authors of the paper argue that the process has advantages over corn ethanol and other plant oil-derived biodiesels, as its production doesn't require the use of anything that could be a food source, which means no issues with higher prices or questionable land use practices.

Nature, 2010. DOI: 10.1038/nature08721