The Next Big Thing #8: Brewing A Better Biofuel

Our efforts at shifting from fossil fuels to biofuels have been largely a bust so far. Using corn as a feedstock takes food off the table or drives up its price—with little or no reduction in carbon dioxide emissions. It would make more sense to turn farm wastes such as corncobs and stalks into biofuel. So far, though, it’s been too difficult to break down tough, woody fibers into simple sugars. But tweaking the relationships within teams of microbes may provide a way forward. University of Michigan researchers recently teamed the fungus Trichoderma reesei, which breaks down corn stalks and other tough plant wastes into sugars, with a strain of the bacterium Escherichia coli that had been genetically engineered to convert the sugars into isobutanol. Isobutanol produces about 82 percent as much energy as gasoline, a big jump up from the 67 percent produced by ethanol—and the process still leaves the edible part of the plant on the dinner table.