Some people say that biofuels are horse-pucky, and they may be right: the key to getting a gasoline substitute could be hiding in piles of it.

Scientists have discovered that the fungi that grows on manure plays a big role in breaking down the plant material — a process that, in the biofuel industry, is expensive. But taking a cue from the fungi could provide a cheaper way.

Currently extracting biofuel from plants is difficult and expensive because the sugars needed to make alcohol are bound up in cellulose, which is locked away in the lignin in the plant’s cell walls. Breaking down the cellulose requires treating the plant material.

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But big herbivores like horses and cows have been breaking down plant material for millions of years thanks to enzymes from their digestive tracts. Other enzymes in the fungi that grows in their feces do a simliar thing. If these enzymes can be harnessed for the biofuel industry, it could make biofuels cheap enough to compete with gasoline.

At the National Meeting & Exposition of the American Chemical Society in New Orleans, Michelle A. O’Malley of the University of California, Santa Barbara, said that scientists have been studying the bacteria in the digestive tracts of animals such as horses and cows for years, but not the fungi.

That was largely because the number of fungi found in the cow patties and road apples left behind didn’t have that many fungal species in it, or much fungus. So nobody realized their importance. O’Malley told Discovery News that one hallmark of these fungi is how common they are.

O’Malley’s lab is working on how to get the bacteria currently used in biofuel production to make the enzymes that the fungi do, or culture the fungi at a larger scale. She said one challenge with doing so is that the fungi can’t survive in the presence of oxygen, and their growth media is relatively specialized.

Who said you can’t polish a turd?

Credit: John K. Henske