22 November 2007

Fuel's gold: Termites point way to new dawn of bio-energy

PARIS (AFP) — A team of US scientists poring over the intestines of a tropical termite have a gut feeling that a breakthrough in the quest for cleaner, renewable petrol is in store.
Tucked in the termite's nether regions, they say, is a treasure trove of enzymes that could make next-generation biofuels, replacing fossil fuels that are dirty, pricey or laden with geopolitical risk.
Termites are typically a curse, inflicting billions of dollars in damage each year by munching through household timber with silent, relentless ease.
But gene researchers say the hind gut of a species of Central American termite "harbour a potential gold mine" of microbes which exude enzymes to smoothly break down woody fibres and provide the insect with its nutrition.
Present-generation biofuels are derived from corn, sugar and other crops, whose starch is converted into ethanol by enzymes, fermentation and distillation.
One of the problems, though, is that this product entails converting food into fuel. Hefty US subsidies to promote bio-ethanol is having price repercussions across swathes of the global food market.
Next-generation biofuels, though, would use non-food cellulose materials, such as wood chips and straw. But these novel processes, hampered by costs and complications, are struggling to reach a commercial scale.
The termite's tummy, though, could make all the difference.
Like cows, termites have a series of intestinal compartments that each nurture a distinct community of microbes.
Each compartment does a different job in the process to convert woody polymers into the kind of sugars that can then be fermented into biofuel.
The US team has now sequenced and analyzed the genetic code of some of these microbes in a key step towards -- hopefully -- reproducing the termite's miniature bioreactor on an industrial scale.
Their work, published on Wednesday in Nature, required scientists to venture into the rainforests of Costa Rica, where they plucked bulbous-headed worker termites from a large nest at the foot of a tree.
Using fine forceps and needles, they extracted the contents of the third paunch, or hind gut, from 165 termites, and sent this to a lab in California for sequencing.
From this, some 71 million "letters" of genetic code emerged, pointing to two major bacterial lineages called fibrobacters, which degrade cellulose, and treponemes, which convert the result to fermentable sugars.
Termite guts are incredibly efficient, said Andreas Brune of the Max Planck Institute for Terrestrial Microbiology in Marburg, Germany.
"In theory, they could transform an A4-sized sheet of paper into two liters (1.8 pints) of hydrogen," he said.
Eddy Rubin, director of the Joint Genome Institute (JGI), an organisation that comes under the aegis of the US Department of Energy, said an important fundamental step had been made, even if a long road still lay ahead.
"Scaling up this process so that biomass factories can produce biofuels more efficiently and economically is another story," said Rubin.
"To get there, we must define the set of genes with key functional attributes for the breakdown of cellulose and this study represents an essential step along that path."
Other scientists taking part in the project were from the California Institute of Technology (Caltech), biofuels company Verenium Corp., the National Biodiversity Institute (INBio) of Costa Rica and the IBM Thomas J. Watson Research Center.

1 comment:

Ophira said...

Good words.