Posting in Energy
A new review that touts switchgrass as an ideal biofuel comes on the heels of a recent research milestone to engineer e.coli bacteria strains that help produce transportation fuel.
Researchers with the U.S. Department of Energy's Joint BioEnergy Institute (JBEI) have engineered the first strains of e.coli bacteria that can digest switchgrass biomass and synthesize its sugars into gasoline, diesel and jet fuel. And all without having to add expensive enzyme additives.
The upshot? The cost of switchgrass-based biofuel could be greatly reduced and help it compete with fossil fuel-based transportation fuels. JBEI CEO Jay Keasling explained in a recent announcement the use of e.coli has allowed researchers to "reduce fuel production costs by consolidating two steps -- depolymerizing cellulose and hemicellulose into sugars and fermenting the sugars into fuels -- into a single step or one-pot operation."
This research milestone, which was announced two weeks ago, comes at a time when switchgrass continues to gain credibility as a viable next-generation cellulosic feedstock. A new research review published today in GCB Bioenergy not only confirms the viability of switchgrass, but adds that it may have greater carbon emission fighting abilities than other alternatives.
How the e.coli bacteria does its job
The cellulose and hemicellulose are embedded in woody material called lignin found in plant biomass, making it a challenge to extract. Once the cellulose and hemicellulose have been isolated they're converted into simple sugars and then turned into fuel.
The folks at JBEI have been pre-treating the biomass with molten salt to dissolve it, then engineer a single microorganism that can digest the biomass and produce hydrocarbons that have the same properties found in petrochemical fuels, according to the research center. The researchers engineered a strain of e.coli that can use the cellulose and hemicellulose fractions of switchgrass that's been pre-treated with molten salt.
E.coli has been used in the past to produce gasoline and diesel from sugars. But this is the first demonstration of the bacteria to produce all three varieties of transportation fuels. Researchers says the techniques used in this case should be adapted to other microbes, which could the production of advance biofuels progress towards commercial viability. According to JBEI, researchers will focus their efforts on increasing yields of the fuels they can synthesize from switchgrass.
Photo: Lawrence Berkeley National Laboratory
Dec 13, 2011
Most gm e coli cannot survive in the intestines. But I am not in support of gmo. Anything could happen. There are natural ways to be sustainable.
And what happens when this special bacteria decides to leave the confines of the lab and find its way into the environment and mutate into something else? We are playing God here folks. If nature thought it necessary after billions of years of trial and error to produce such a bacteria for this purpose, it would have already been produced and working in the environment. We are risking polluting the environment with a new strain of bacteria that could easily cause more harm than good. Don't be surprised if a new super bug suddenly appears to cause untold damage to the planet. Fear mongering? Yes. Someone has to stand up for the environment and ask pointed questions before we go headlong into a reckless pursuit of energy solutions that may not be as beneficial as we think. Convince me I'm wrong. Show me the safeguards. As we all know, blowout preventers don't always work.
...to switchgrass if you are producing gasoline, diesel and other carbon rich fuels with it. When combusted, it releases CO2 into the atmosphere, which would no doubt counteract any carbon sequestered by the root system. It would be interesting to see how much it reduces the amount of energy expended during the refining process, tho. My guess is that it might very well be a net improvement from, say, transporting and refining tar sands.
The point behind using something like switchgrass as the starting point for fuel instead of oil is that the carbon has to be taken out of the atmosphere for the fuel to be made. The fuel is then burned and the carbon reenters the atmosphere, but the change can be close to neutral in terms of overall CO2 in the atmosphere. When we drill for oil we are taking a previously sequestered carbon pool and putting it into the atmosphere.
Thanks for the rationale--makes sense to me. It certainly makes more sense than the lousy energry return on energy invested ratio of something like tar sands. It seems certainly worth following to see if it can be scaled up to where it is commercially viable and I suppose other perennials like miscanthus might provide a suitable stock as well?