Published on November 29th, 2011 | by Tina Casey4
E. Coli Bacteria: What Doesn’t Kill Us, Makes Us Biofuel
November 29th, 2011 by Tina Casey
That notorious killer bacteria e. coli is making renewable biofuel hand over fist for researchers at the U.S. Department of Energy. Scientists based in DOE’s Joint BioEnergy Institute have tweaked a strain of the bug to munch on tough-to-digest switchgrass like it’s sugar candy, and the result is a process that yields not one biofuel but three: renewable gasoline, diesel and jet biofuel. Hey, it’s like the Ginsu Knife of biofuels, right down to the low-low price.
More Biofuels, Less Money
Cost competitiveness really is the bottom line for biofuels, and that’s where E. coli (short for of Escherichia coli) comes in. According to Jay Keasling, the CEO of the BioEnergy Institute, the new strain of bacteria will cut costs by eliminating expensive steps that are otherwise needed to break down the tough cell walls of woody plants like switchgrass, to get at the goodies inside. In a press statement, Keasling described the e. coli-fueled process as a “one pot operation.”
E. Coli and Biofuel Crops
If you recall the corn ethanol craze that marked the end of the previous president’s administration (okay, so George W. Bush – hey, whatever happened to that guy?), you may also recall that U.S. biofuel policy at the time helped to spur a global food crisis by diverting too much corn to refineries. President Obama’s administration has focused on a biofuel policy that emphasizes non-food biomass, which places a heavy load on switchgrass and other weedy or woody grasses and plants. The downside has been the extra expense of breaking down these tougher plants, and the new strain of E. coli offers a way out.
E. Coli Biofuels – But Wait, There’s More!
The new process packs in another benefit compared to corn-based biofuel refining. Corn starch yields ethanol, which don’t replace any commonly used transportation fuel entirely. That’s why you can’t get
pure ethanol when you go to the gas station, only ethanol blends. The new strain of E. coli produces biofuel substitutes and precursor molecules that can produce gasoline as well as diesel and jet biofuel on a gallon-for-gallon basis.
How Do They Do It?
Writer Lynn Yarris at the Lawrence Berkeley National Laboratory (a partner in the BioEnergy Insititute) explains that conventional strains of E. coli bacteria can’t grow on switchgrass, so the research team engineered strains that express an enzyme enabling them to get nourishment from cellulose (the tough material in plant cell walls) and hemicelllose (a weaker substance also present in cell walls). With additional adjustments to the bacteria’s metabolic pathways, the team was able to produce the three biofuels. There is also one additional secret: the switchgrass was pretreated in a bath of molten salt to soften it up.
But Wait, There’s Green Jobs
A good chunk of the President’s biofuel policy is geared toward creating permanent green jobs in rural areas, helping small, far-flung communities achieve economic sustainability and civic stability. That’s a far cry from the temporary housing camps sprouting in the western U.S. where oil fields are booming. The oil money, apparently, is good for now but when those wells tap out, there goes the neighborhood.
Image: E.coli bacteria for biofuel courtesy of Lawrence Berkeley National Laboratory.