Termites and Microbes
For now Leadbetter is content to learn more about the insects and the inhabitants of their guts.
"This is a fascinating group of insects that do a fascinating activity and play important roles in the global ecosystem," he said.
According to Leadbetter, an estimated 2,600 termite species comprising more than a quadrillionthat's 1 followed by 15 zerosindividuals are crawling the Earth.
"In terms of current activity, they do turn over a lot of plant material," he said.
Hydrogen and other gases are produced inside termites' hindgutsan area roughly equivalent to the colon in humanswhere "several hundred" unique microbe species reside, Leadbetter said. The species of microbes vary among termite species.
The microbes and termites have what scientists call a symbiotic relationship: Neither could exist without the other.
The termites use their jaws to turn the woody plant material and soil they bore through into tiny particles that the microbes can process.
The metabolism of the microbes in turn converts the woody food to acetate, which is essentially a kind of vinegar that the termites absorb as their major nutrition source.
Such symbiotic relationships are fairly common in nature. Cows and other animals rely on microbes to process the foods they chew into energy. Even human guts are filled with microbes. (Read "Deciphering the 'Bugs' in Human Intestines.")
But cows eat grass, not wood, and they emit lots more methane per pound of plant material processed than termites do, Leadbetter said.
Methane is a so-called greenhouse gases that traps heat in Earth's atmosphere.
According to the U.S. Environmental Protection Agency, cows and other ruminant livestock are responsible for 28 percent of global methane emissions from human-related activities.
By contrast, termites are responsible for about 4 percent of global methane emissions.
And the microbes in human guts can't process woody plant material like those in termites and cows.
So Leadbetter and colleagues at Diversa Inc. in San Diego, California; the U.S. Department of Energy's Joint Genome Institute in Walnut Creek, California; and Costa Rica's National Biodiversity Institute are focused on termites and their gut microbes.
If they can figure out which enzymesor proteins inside the microbesbreak apart the wood into materials like hydrogen, the researchers in principle could scale up the process for industrial applications.
And given all the wood chips and leftover waste from harvesting trees and other crops, that would be a "novel way of converting low-value starting material into a higher value product," Leadbetter said.
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