|A MOLECULAR WRECKING YARD: Electron-micrograph images of the termite's third gut, where food is turned into fuel|
(Images by Falk Warnecke, Phil Hugenholtz, Doe Joint Genome Institute and Manfred Auer, UC Berkeley and Lawrence Berkeley National Laboratory)
For more than a hundred million years, termites have lived in obscurity, noticed only by the occasional hungry anteater or, more recently, by dismayed homeowners. Other social insects, such as bees and ants, are celebrated for their industriousness and engineering feats, but popular culture has not gotten around to cheering on termites for theirs—even though they build mounds as tall as 20 feet, which may be oriented north-south as accurately as if plotted with a compass, in order to maximize heat from the sun. The extraordinary powers evolution has bestowed on termites—some protect the mound by spraying chemicals from nozzles on their heads at intruders, while others have snapping mandibles that can decapitate invading ants—have similarly failed to elevate their status. On the contrary: last year, scientists at the London Natural History Museum called termites “social cockroaches” and proposed reclassifying them, in a paper brusquely titled “Death of an Order.”
Video: "How to Hunt for Termites"
Lisa Margonelli captures highlights from her termite-hunting trip in the Arizona desert with Department of Energy researchers
The more closely one examines the termite, the more mysteries one finds. In some species, if a termite discovers a contamination in the mound, it alerts everyone else, and a hygiene frenzy begins. As a disease passes through a mound, the survivors vaccinate the young with their antennae. When a mound’s queen is no longer capable of reproduction, the workers may gather around her distended body and lick her to death.
The greatest mystery of all is found in the worker termite’s third gut, which is delineated by an intricately structured stomach valve, as unique from species to species as individual snowflakes are and, in its way, just as lovely. The size of a sesame seed, the third gut contains a dense mush of symbiotic microbes. Many of these microbes live nowhere else on Earth; they depend on adult termites to pass them on to the young by means of a “woodshake,” a microbial slurry.
This microbial mush may be a treasure trove for the human race. Recently, sophisticated genetic sequencing produced an inventory of more than 80,000 genes, spanning some 300 microbial species, from the guts of Costa Rican termites. These findings, published last November in the journal Nature, got a lot of attention, not for the quantity of microorganisms—after all, the human mouth contains 600 species of bacteria—but for their complexity, and in particular for the fact that among them are 500 genes for enzymes able to break down the cellulose in wood and grasses.
With oil prices at historic highs, the quest is on to turn such plant materials into a replacement for gasoline—call it grassoline. Since 2007, U.S. energy policy has been shaped by the premise that we can brew enough biofuels to replace 35 billion gallons of gasoline by 2017, and 60 billion by 2030. Corn ethanol has been a bust, blamed for wasting water, exhausting croplands, and causing tortilla shortages in Mexico and rice shortages in Asia. For all these problems, it currently contributes the equivalent of only about 4.2 billion gallons of gas a year. And the carbon dioxide emitted in the process of growing and fermenting corn and then distilling and burning ethanol is nearly as much as that emitted by extracting, refining, and burning gasoline.
Wood and grasses seem to hold more promise. They contain chains of thousands of glucose molecules that could be made into so-called cellulosic ethanol and then burned like gasoline, while releasing just 15 percent of gasoline’s greenhouse-gas emissions. But there’s a catch. Wood has evolved to keep its sugars to itself, covering them with lignin—a substance that gives cell walls rigidity—and then locking them in a matrix of cellulose and hemicellulose protected by complex chemical bonds. Because these sugars are so hard to get at, our output of cellulosic ethanol is still, after decades of research, just 1.5 million gallons a year—less than 1 percent of one day’s gasoline consumption.
But where humans have failed, the termite succeeds—spectacularly. A worker termite tears off a piece of wood with its mandibles and lets its guts work on it like a molecular wrecking yard, stripping away sugars, CO2, hydrogen, and methane with 90 percent efficiency. The little biorefineries inside each termite allow the insects to eat up $11 billion in U.S. property every year. But some scientists and policy makers believe they may also make the termite a sort of biotech Rumpelstiltskin, able to spin straw—or grass, or wood by-products—into something much more valuable. Offer a termite this page, and its microbial helpers will break it down into two liters of hydrogen, enough to drive more than six miles in a fuel-cell car. If we could turn wood waste into fuel with even a fraction of the termite’s efficiency, we could run our economy on sawdust, lawn clippings, and old magazines.
And so the termite may be poised for its moment in the sun. Speaking last year about moving toward a biofuel economy, Energy Secretary Samuel W. Bodman pointed to the termite-to-tank concept, asserting, “We know this can be done.” Another official called it a promising “transformational discovery.” Suddenly the termite is everywhere, from Popular Science to Congressional Quarterly Today to Wired. With the audience for energy speeches and articles so small and wonky, it’s too soon to say that the little bug has exactly become a celebrity (although it did recently rate a footnote in Vanity Fair). But in some circles, it has attained a certain status as the pest that could solve our energy problems, transforming geopolitics and agriculture in the process. “Deus ex termita,” you might say.