Researchers Seeking Cheap Way to Produce Ethanol
The key to kicking what President Bush calls the nation’s oil addiction could very well lie in termite guts, canvas-eating jungle bugs and other microbes genetically engineered to spew enzymes that turn waste into fuel.
It may seem hard to believe that microscopic bugs usually viewed as destructive pests can be so productive. But scientists and several companies are working with the creatures to convert wood, corn stalks and other plant waste into sugars that are easily brewed into ethanol.
Thanks to biotechnology breakthroughs, supporters of alternative energy sources say that after decades of unfulfilled promise and billions in government corn subsidies, energy companies may be able to produce ethanol easily and inexpensively.
“The process is like making grain alcohol, or brewing beer, but on a much bigger scale,” said Nathanael Greene, a Natural Resources Defense Council analyst. “The technologies are out there to do this, but we need to convince the public this is real and not just a science project.”
Using microbes may even solve a growing dilemma over the current ethanol manufacturing process, which relies almost exclusively on corn kernels and yielded only 4 billion gallons of ethanol last year (compared with the 140 billion gallons of gasoline used in the U.S.). There’s growing concern in the Midwest that the 95 ethanol plants are increasingly poaching corn meant for the dinner table or livestock feed.
The idea mentioned by Bush during his State of the Union speech -- called “cellulosic ethanol” -- skirts that problem because it makes fuel from farm waste such as straw, corn stalks and other inedible agricultural leftovers.
Breaking cellulose into sugar to spin straw into ethanol has been studied for at least 50 years. But the technological hurdles and costs have been so daunting that most ethanol producers have relied on heavy government subsidies to squeeze fuel from corn.
Researchers are now exploring various ways to exploit microbes, the one-cell creatures that serve as the first link of life’s food chain. One company uses the microbe itself to make ethanol. Others are taking the genes that make the waste-to-fuel enzymes and splicing them into common bacteria. What’s more, a new breed of “synthetic biologists” are trying to produce the necessary enzymes by creating entirely new life forms through DNA.
Bush’s endorsement of the waste-to-energy technology has renewed interest in actually supplanting fossil fuels as a dominant energy source -- a goal long dismissed as a pipe dream.
“We have been at this for 25 years, and we had hoped to be in commercial production by now,” said Jeff Passmore, an executive vice president at ethanol maker Iogen Corp. “What the president has done is -- perhaps -- put some wind in the sails.”
Ottawa-based Iogen is already producing ethanol by exploiting the destructive nature of the fungus Trichoderma reesei, which caused the “jungle rot” of tents and uniforms in the Pacific during World War II.
Through a genetic modification known as directed evolution, Iogen has souped up fungus microbes so they spew copious amounts of digestive enzymes to break down straw into sugars. From there, a simple fermentation -- which brewers have been doing for centuries -- turns sugar into alcohol.
Although no commercial interest has advanced as far as Iogen, other biotech companies are engineering bacteria to spit out similar sugar-converting enzymes, and academics are pursuing more far-out sources.
At Caltech, Jared Leadbetter is mining the guts of termites for possible tools to turn wood chips into ethanol. Leadbetter said there are some 200 microbes that live in termite bellies that help the household pest convert wood to energy.
Those microbes or their genetic material can be used to produce ethanol-making enzymes. So scientists at the Energy Department’s Joint Genome Institute in Walnut Creek, Calif., are now sequencing the microbe genes in hopes of finding a key to ethanol production.