In Bed With the Bugs:
Why Termites Could Teach Us a Thing or Two
Corn was a poor choice as a feedstock for a gasoline substitute. In the most favorable studies, corn derived ethanol yields only 1.3 times the energy it takes to produce it, and diverting it from the food chain has caused higher prices that have even led to some rioting in Mexico.
The grail has been to make ethanol from cellulosic plant life that is, waste such as wood chips, or grasses such as miscanthus and switchgrass. They grow rapidly, need
no fertilizer, yield energy six to seven times that of corn, and release only 15% of the CO2 of gasoline.
But nothing’s easy. Whereas corn readily yields its sugar for micro-organisms to ferment into ethanol, cellulosic plants are grudging. Their stalks are wrapped in lignin, to make them sturdy, and the cellulose within is a large, structural molecule that puts up a fight before releasing its sugar. Which explains our slow progress in getting beyond corn ethanol: our annual production of cellulosic ethanol is less than 1% of a single day’s gasoline consumption.
Put a Bug in Your Tank
That’s where termites come in. Given the rough patch we’ve hit trying to dissect cellulose, we are suddenly in awe of the termite’s ability to unlock the sugars in something so
unpromising as wood and convert them to nutrients. How on earth do they do it? Could mankind learn the same tricks and set termites to work making fuel?
Termites are just one of nature’s workers that scientists at entrepreneurial companies are exploring for making fuel and even
plastic. A California company named LS9 reworks the DNA of organisms such as yeast and non-pathogenic variants of E coli to produce and we’re not kidding crude oil. To understand how this could be possible, focus on “fossil” in “fossil fuel”, that is, substances made of ancient living
matter. Oil and gas are hydrocarbons, molecular chains of hydrogen and carbon that are the building blocks of all life, and therefore not alien even to single-cell organisms a billionth the size of an ant. LS9 makes the point that crude oil “is only a few molecular stages removed from the fatty acids normally excreted by yeast or E coli during fermentation”. Tweak their DNA and out comes a substance nearly ready for your gas tank. That would eliminate the final, energy-intensive distillation step required for corn ethanol.
Amyris is another California company that is using micro-organisms such as yeast and bacteria to convert the sugars in biomass into an ethanol to compete with petroleum-based diesel. The DNA sequencing of these life forms now makes it possible, says this company, to modify them so as to make some 50,000 variants of molecules used in energy, pharmaceutical, and chemical applications.
Wherever you look in the DNA world, you will find J. Craig Venter, whose institute in Maryland announced early in 2008 that it had replaced the entire genetic code of a harmful but otherwise useful bacterium with the code of a different but benign relative. Like the others, the goal of his company, Synthetic Genomics, is to strap these miniscule living factories in harness and put them to work. “Obviously, if we made an organism that produced fuel, that could be the first billion or trillion-dollar organism,” he told Newsweek.
Oil to Replace Oil? What’s the Point?
But what gain is there in reducing CO2 emissions if oil or its derivatives is the end product of these breakthroughs? Considerable gain is the answer. When oil, gas and coal are extracted, they bring to the surface for burning carbon dioxide deeply sequestered under Earth’s mantle, adding a new burden of CO2 into the atmosphere. In contrast, all the biomass technologies are at least carbon neutral: they release back into the air only the CO2 that they have drawn from it during their plants’ growth. In the case of wood chips, wheat straw and other agricultural waste, the CO2 would have been released anyway, once they decompose.
Any plant matter any material containing hydrogen, carbon and oxygen will serve as raw material for microbial hordes to make molecules of choice, so long as it can be broken down into the sugars needed for fermentation into fuel. That means that construction debris, forest and lawn trimmings, wood chips, wheat straw and many other types of agricultural waste are all candidates for rescuing us from our oil addiction.
Plastics, too, have hydrogen and carbon as their base (8% of global oil production goes into plastics), which means they are another material that can be excreted by masses of microbial conscripts retrained to do mankind’s bidding. From a standing start in 2006, DuPont is already selling $100 million of “bioplastics” a year, principally under a brand name, Sonora. Multinational giant Cargill, based in Minnesota and known mostly for grain, is also in the market, shipping 140,000 metric tons of a bioplastic trade-named Ingeo for use in such products as food containers. A host of smaller companies around the world have entered this market. Best of breed may be an outfit named Metabolix in Cambridge, Massachusetts, which has hundreds of patents for its process of using bugs to cook up bioplastics in its vats, but with the added distinction that its brand, Mirel, degrades to “nice brown dirt” after about 180 days, said a tester for the state of California.
From Scourge to Savior?
So what about those termites? Scientists have been trying to learn how they succeed so spectacularly in tearing down wood and coaxing out its sugars, CO2, hydrogen and methane. It’s part of a $375 million program at the U.S. Department of Energy research centers that funds seven government labs, 18 universities, and a few private companies. They are laboring under a legislative mandate that the country use 36 billion gallons of biofuels a year by 2022, with cellulosic ethanol use to exceed corn ethanol by then. Studying how tiny creatures are able to break down cellulose and extract its sugars has to be a humbling pursuit, but termites a critter that instills terror in homeowners have been getting a lot of respect from scientists lately.
A termite has a third gut. Researchers were taken aback to discover that, while no bigger than a rice grain, it is filled with a slurry containing 300 different microbes many found nowhere else on earth as well as 500 different genes, enzymes and catalysts a bewildering assemblage all brought together by nature for the task of deconstructing wood. Faced with this array, scientists are having trouble determining just which members of this teeming population are key to getting the job done. They may find that nature is just too complicated for mere humans to grasp. Even if nature gives up its secrets, there may be no way to ramp up a termite’s methods to industrial scale. But it will be frustrating to abandon the bug because, in addition to its superiority over lesser woodcutters, termites miraculously produce little methane as they munch. In contrast, the bacteria in the gut of cows lose 20% of the energy in the grass the cow just ate to methane, a greenhouse gas that traps 20 times the heat of CO2.
Maybe the next candidate is not a bug but a fungus discovered by Gary Stobel, a professor of plant pathology from Montana State University. He was poking about in Patagonia when he eyed a red fungus that had a gaseous smell. It proved to be a mix of hydrocarbons that the fungus gives off as it consumes cellulose. He was so astonished that “every hair on my arms stood on end”. Unlike termites and other bugs that unlock the sugars in cellulose which then need to be fermented into fuel, this fungus is a one stop factory, taking cellulose all the way to many of the same hydrocarbons found in diesel fuel.
All for Naught?
But the question is now what happens, with gasoline dropping once again below $2 a gallon $1.67 at year end. The economics of invention cannot compete with mature industry, and in these United States money rules. We veer between “shock and trance”, said our new president. Just as we were seduced by the cheap gas of the 80’s that caused us to forget the lines at the pump from OPEC’s embargo in the 70s’, will we, after the shock of $4.00 a gallon gasoline just this past summer, fall again into our usual amnesiac trance, all lessons again forgotten, all bad habits resumed? Unless the leadership of this country decides that gas should never be below $4.00 a gallon it’s a national security matter that transcends the economic woes of the moment, and a planetary matter that transcends mankind the U.S. will continue to slide to and fro on an oil slick, and all the innovative companies you have just read about will be driven out of business.
- Stephen Wilson