Scientists working out bugs
for use in biofuel production
Monday, February 19, 2007
Monday, February 19, 2007
By Ian Hoffman
Barely a year ago, when President Bush first endorsed biofuels as an answer to the nations "addiction to oil," scientists already were salivating at biologically engineering ordinary grasses and trees into full-blown energy crops.
The likeliest prospects - poplar, switchgrass and a towering Asian ornamental grass called miscanthus - really haven`t been bred or genetically modified for human purposes. They are almost as wild and virginal as teosinte, that ancient bushy grass that American Indians domesticated into corn, now the foundation of Western grain, animal feed and lately alternative fuel.
That grain underwent a "green revolution in the 1960s as selective breeding and new growing techniques boosted crop yields to six times the tonnage per acre. As the world`s largest scientific organization assembled this week in San Francisco, researchers talked of bringing the same revolution to bear on other energy crops, but they`ve dropped yesteryear`s speculation about plantations of black trees for maximum solar absorption and grasses genetically inserted with self-devouring enzymes, programmed, in effect, with the seeds of their own destruction.
The change in message has been driven by the realization that genetically modified energy crops could be politically controversial and take years to gain regulatory approval.
"This industry is not going to be built on genetically modified plants. They`re not going to appear within 15 years, biofuels expert
Chris Somerville, chairman of the Carnegie Institution`s Department of Plant Biology at Stanford University, said Friday at the annual meeting of the American Association for the Advancement of Science.
Instead, many scientists are saving the tools of genetic modification and synthetic biology for the microbes that are the workhorses of every biorefinery. Those germs digest plant matter into sugars, then ferment those sugars into fuels.
For now, the U.S. biofuels industry is built on corn, milled and fermented by a highly inefficient process into the same kind of alcohol found in whiskey.
Berkeley researchers say ethanol costs almost as much energy to make as it delivers, while producing more planet-warming greenhouse gases in many cases than just burning plain gasoline.
"In the future there will be a variety of new species that have not been used on a large scale as energy crops, and these species will have different requirements as inputs than current field crops, said Somerville, who has been offered the directorship of the new Energy Bioscience Institute funded by energy giant BP Amoco PLC at Lawrence Berkeley National Laboratory and the University of California, Berkeley. Those plants regrow year after year, unlike corn, and need less fertilizer and water, the costliest inputs to energy crops, Somerville said.
Ordinary grasses and trees are 75 percent sugars by weight, presenting more mass for conversion to fuel, but also have more complex plant fibers and more sugars that are more difficult to convert to fuel than simple corn starch.
That`s where the bugs come in.
In the hunt for efficiently destructive bugs, scientists for such companies as Diversa Corp. are reaching into the stomachs of cows, tapping hot volcanic vents and hiking deep into Costa Rica`s jungles to trap some of the worlds most ravenous termites. They are finding huge communities of bacteria, fungi and protozoa work together.
The trick is identifying the best recipe of genes and conditions for converting plant fibers into sugars or some other fuel precursor.
The U.S. Energy Departments Joint Genome Institute in Walnut Creek has been decoding the germs` DNA as part of a project with Diversa and other companies to identify those genes so they can be cobbled together into superbugs capable of turning different plant fibers and wastes into fuel.
Pursuit of such "frankenbugs" and new combinations of enzymes is really just beginning, according to Melvin Simon, a Caltech biology professor and Diversa board member.
"People are looking like mad, and there are hundreds and hundreds of these genes," Simon said at the annual meeting of the American Society for the Advancement of Science. "Nobody as far as I know can think of a superbug that can eat your table."
The potential gains in efficiency for the conversion of plant and waste mass into ethanol or other fuels are enormous, said Eddy Rubin, director of the Joint Genome Institute.
"Right now were where we were with the Human Genome Project 15 years ago. It`s very inefficient and very costly," he said. "There`s a lot of low-hanging fruit that will make things two times, three times and 10 times less in cost."
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