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Does the panda hold a key to the greenest biofuels?

By Martin Leggett - 29 Aug 2011 15:31:0 GMT
Does the panda hold a key to the greenest biofuels?

We've long heard of the need for the world to help to Save the Panda - but how about the panda saving the world? That's the promise being touted by one of the papers being presented at the 242nd annual meet of the American Chemical Society (ACS) today. It turns out that panda poop may hold the key to unlocking the potential for the greenest of biofuels - those that can be produced in a carbon-neutral manner, without displacing much-needed land for food crops.

So far, biofuels have come from crops like sugar-cane, corn, and soybeans. That means they take up land that could otherwise be used for feeding the planet - not exactly a sustainable situation. But this latest research shows that panda poop contains something that could turn the biofuel industry on its head - the iconic creature's gut-dwelling microbes.

Panda poop home to critical enzyme

It seems that these bacteria are superb at digesting woody plant-matter - such as grass clippings, crop waste and wood chips - and turning them into useful sugars. Those sugars could form the feedstock for fermenting into ethanol, an already widely used biofuel. Previous attempts to turn 'cellulosic biofuels' into a working proposition have foundered because such a conversion is tricky. But the scientists presenting the paper, Ashli Brown and Candace Williams of Mississippi State University, think the solution may have been lurking panda poop all this time.

"Who would have guessed that 'panda poop' might help solve one of the major hurdles to producing biofuels, which is optimizing the breakdown of the raw plant materials used to make the fuels?" said study co-author Brown. In order to work out exactly which microbes are helping to digest the panda's bamboo-orientated diet, the team went to Memphis zoo to collect panda poop. Fortunately there was no shortage of samples - pandas do produce a lot of poop.

Cows, termites and pandas

That's because pandas are firmly in the sit-and-graze school of survival. They spend up to 16 hours a day sitting and munching vast quantities of bamboo - as much as 40 pounds each day. Virtually all of their waking hours are spent scoffing because bamboo packs such a poor nutritional punch. What little energy pandas do get from the stalks, leaves and shoots comes courtesy of the bacteria in their gut - bacteria that can attack the cellulose that makes up the bulk of the bamboo's mass.

That's something that pandas have in common with termites and cows, who also enlist bugs to help eke out a living from unpromising grasses and woody foodstuffs. But it turns out that the panda's bacteria are kings of the hill, when it comes to getting energy from plant matter. "Our studies suggest that bacteria species in the panda intestine may be more efficient at breaking down plant materials than termite bacteria and may do so in a way that is better for biofuel manufacturing purposes," said Brown. She estimates they can convert 95% of plant mass into sugars.

Lessons of panda conservation

The bacteria manage this conversion process using powerful enzymes, that are able to get the sugars out without needing high pressures, temperatures or acidity. Until now, the biofuels industry has struggled to get useful amounts of sugars at anything except high temperature and pressure. But to turn this research into a working biofuel process, the bacteria producing the enzymes responsible first need to be isolated. The trick would then be to engineer yeasts able to produce those enzymes in bulk. So much more research remains to be done.

In the meantime, the irony of endangered pandas coming to the rescue of mankind casts a new light on issues of conservation and biodiversity. "The discovery also teaches a lesson about the importance of biodiversity and preserving endangered animals," said Brown. "Animals and plants are a major source of medicines and other products that people depend on. When we lose them to extinction, we may lose potential sources of these products."

Top Image Credit: Panda Eating Bamboo © StrangerView