Horse manure yields secret to ethanol fuel


Michelle O’Malley knows good horse poop when she sees it. While at MIT, the chemical engineer scooped up some manure from Finn, a grass-fed horse at a sustainable farm in Concord, Mass.

That offal has led to a potential breakthrough in turning grasses and nonfood crops into an alternative fuel in attempts to wean motorists from fossil fuels and stem man-made climate change.

O’Malley, a chemical engineer at UC Santa Barbara, has isolated a fungus that could more easily unlock the sugars used to ferment ethanol.


“It’s been known for a long time that the digestive tract of large herbivores have been good at turning crude cellulose into sugars,” said O’Malley, who presented her findings Thursday at the American Chemical Society’s annual convention in New Orleans.

Scientists delving into animal guts, however, had previously concentrated on the bacteria that break down cellulose, leaving fungi largely unexplored. It turns out that the fungi, which are not nearly as numerous, have a way of breaking through lignins that are a natural barrier to the cellulose.

That’s important, because getting past those lignins is the most expensive and time-consuming part of the ethanol process, and a potential barrier to cellulose-to-ethanol refineries competing with the heavily subsidized corn-ethanol industry.

O’Malley is focusing on the specific enzymes produced by the fungus. The key will be getting those enzymes to work via organisms that are easier to control, such as yeast, or to engineer the fungi to do what they do better, and in a way that is compatible with an industrial process.

O’Malley also has continued her unorthodox collection. Her team got the Santa Barbara Zoo to provide more good poop -- from an elephant, sheep, goat and giraffe.