Published on September 30th, 2013 | by Tina Casey3
Loads of Good, Clean Biogasoline From Dirty Little Bug
File another one under “what doesn’t kill us, makes us biofuel.” A team of scientists at the Korea Advanced Institute of Science and Technology (KAIST) has been tweaking the metabolic pathway of the notorious bacteria Escherichia coli to make it squeeze out gasoline. If you’re thinking that’s been done before, well, not exactly. While other researchers have been prodding the little germ to produce biofuel precursors, the KAIST team claims that this is the first time that biogasoline has been produced from a living organism.
The Road To Microbial Biofuel
E. coli is best known for its connection to serious and potentially deadly food poisoning, but there are many different strains. Most of them are harmless and it looks like some are downright helpful.
The connection between E. coli and biofuel first came to our attention back in 2008, when our sister site Gas2.org noted that the bacteria could help solve biofuel’s glycerine waste problem. Researchers found that they could make a high-value product, succinate, from glycerine by adding E. coli (succinate has numerous applications such as food and beverage flavorings, dyes, toiletries and medicinals).
By 2010, the field had progressed into biofuel production, as evidenced by a team at Rutgers University that engineered E. coli to overproduce fatty acids, which could then be processed into biofuel.
The following year, a team at the Department of Energy’s Joint BioEnergy Institute announced that it had engineered a strain of E. coli to digest switchgrass, resulting in precursors for gasoline, diesel, and jet biofuel.
The KAIST Biogasoline “Broth”
As described by the KAIST team, the challenge has been to produce the short hydrocarbon chains, or alkanes, characteristic of gasoline. The goal is to produce chains of four to twelve carbon atoms. Previous efforts came close at 13-17 carbon atoms, but that only gets you to biodiesel.
The new research, just published in the journal Nature, describes a strategy for producing gasoline-sized chains from E. coli. The first two steps involve screening and engineering enzymes and metabolic pathways to focus on short-chain fatty acid production.
Where the rubber hits the road is getting the fatty acids to convert to their corresponding gasoline alkanes, which the team achieved by introducing a new pathway while enhancing the culture environment.
The result is a gasoline solution or “broth,” from which the team was able to extract about 580 mg of gasoline per liter.
That’s a fairly low concentration in terms of cost-effectiveness, so the next step is for the team to work on increasing the efficiency of the pathway. The team also anticipates producing other valuable fuels and chemicals from the same process.
Advanced Fuels For A High Tech Future
Given all the technological developments that have come about since the invention of the automobile, the idea of digging around in the ground to retrieve ancient liquids, with all of its attendant risks, seems more and more out of step with the 21st century. Factor in population growth and the explosion of demand for personal mobility worldwide, and it’s hard to see how today’s network of drilling fields, pipelines, highways, railways and marine shipping routes can continue growing without a consequent increase in negative impacts including spills, breaks and shipping related emissions.
If the field of E. coli fuel production bears out, it looks like vast rows of Petri dishes, vats or tubes tucked away in sterile warehouses will be the wave of the future. That would free fuel production from geography and open up the potential for hyper-local fuel production, reducing a substantial amount of environmental and public health risks.