Rose scent in poplar trees? WSU turns to genetic engineering
A WSU team aims to turn poplars and other fast-growing trees into living factories that churn out valuable chemicals.
Seattle Times science reporter
2-phenylethanol: An aromatic alcohol. It occurs widely in nature and is found in a variety of essential oils, including rose, carnation, hyacinth, Aleppo pine, orange blossom, ylang-ylang, geranium, neroli and champaca.
Sniff the air around Norman Lewis’ experimental poplars, and you won’t pick up the scent of roses.
But inside the saplings’ leaves and stems, cells are hard at work producing the chemical called 2-phenylethanol — which by any other name would smell as sweet.
Sweeter still is the fact that perfume and cosmetics companies will pay as much as $30 an ounce for the compound that gives roses their characteristic aroma. Because what Lewis and his colleagues at Washington State University are really chasing is the smell of money.
Born out of the frustrating quest to wring biofuels from woody plants, the WSU project takes a different tack. Instead of grinding up trees to produce commercial quantities of so-called cellulosic ethanol, their goal is to turn poplars into living factories that churn out modest levels of chemicals with premium price tags.
The potential market for specialty chemicals — many of which are now synthesized from petroleum — is big, said Lewis, director of WSU’s Institute of Biological Chemistry. He’s already patented some of the technology, which relies on genetic engineering, and created a spinoff company called Elasid.
In the longer term, the profits from high-end products could boost the struggling biofuel industry by helping companies survive what’s called the “valley of death” — the point where firms need to scale up production, but money is hard to come by.
The ideal operation would combine the two product lines, extracting valuable chemicals and using the waste for biofuel. But that’s a long way off, Lewis said.
“Biofuels don’t provide a compelling economic case at this point in time,” he said. “We’ve been trying for many decades to understand how plants make these special chemicals that can be used in flavorings, fuels and medicinals, and that seemed like the obvious first place to target.”
But failures outnumber successes in the world of green technology, and it remains to be seen whether Lewis and his group will buck the trend.
Costs and controversy
Extracting chemicals from plants can be very costly, cautioned Oregon State University bioengineer Ganti Murthy. He and his colleagues engineered poplars to produce a component of biodegradable plastics. But they haven’t been able to get the concentrations high enough to make it profitable.
“Economics play a huge part in all of this,” he said.
The use of genetic engineering also adds an element of controversy and layers of regulation that many companies and investors would rather avoid, Murthy pointed out.
No genetically engineered forest trees have been approved for commercial use in the U.S., though the Department of Agriculture is considering an application from a company called ArborGen that has developed a cold-tolerant eucalyptus. (Papaya trees genetically engineered to resist the ring spot virus are grown in Hawaii.)
Activists who firebombed the University of Washington’s Center for Urban Horticulture in 2001 mistakenly thought they were targeting genetically engineered poplars. Several environmental groups continue to wage battle against transgenic trees, which they fear will contaminate native forests and raise the risk of fire.
“Trees are not like crop plants,” said Anne Petermann, executive director of the Global Justice Ecology Project, a New York-based group that has called for a ban on GE trees. “We have no idea what the long-term impacts will be and very little idea of the short-term impacts, like interactions with soil microorganisms and wildlife.”
Lewis believes the concerns will abate once genetic engineering begins to yield useful products. But in the meantime, he and his team prefer not to disclose the exact location of their test plots.
With 12,000 trees on about 11 acres in Western Washington, Lewis believes his poplars represent the biggest ongoing field test of genetically engineered trees in the country — and perhaps the world.
Under USDA regulations, every tree is tagged and its GPS coordinates noted, explained WSU staff scientist Barri Herman, who oversees the field trials. Each plot is bordered by a wide buffer, which Herman and his crew spray with Roundup and patrol for wayward shoots. If any sapling disappears, the rules require them to track it down — which sometimes means digging up vole burrows, Herman said.
To prevent crossbreeding with other trees, the genetically engineered poplars are cut by the age of 5, before they are able to flower and produce pollen.
Some of the trees in the experimental plots were genetically altered to produce lower amounts of lignin. The matrix that makes wood strong and rot-resistant, lignin is the bane of those who want to break wood down into its component chemicals.
A second batch of poplars contains genes inserted from other plants that coax the trees to produce clove- and basil-scented chemicals.
But it’s the trees with the added rose gene that seem the most economically promising, Lewis said. In a recently published study, he and his colleagues reported that young plants contained up to 4 percent of the chemical in their leaves. The team hopes it may eventually be able to increase those concentrations tenfold.
Not only is 2-phenylethanol used in products ranging from talcum powder to soft drinks, it can also be processed to produce components of jet fuel, Lewis said.
People have been extracting medicines, oils and other useful chemicals from plants for centuries. But the push to find alternate sources of energy has increased the funding and focus on biofuels and other plant-derived substances that could be substituted for petrochemicals.
Ethanol made from corn is a common ingredient in gasoline but has raised concerns over the use of crops and farmland for fuel.
Plants become products
WSU and the University of Washington are sharing in an $80 million U.S. Department of Agriculture grant to find ways to convert trees and waste wood to jet fuel. The federal government has invested $2 billion in research and loan guarantees to help companies produce fuel from nonfood plants.
But it’s harder and more expensive to make ethanol from wood and grass than from corn. So far, no one has been able to produce significant amounts of cellulosic ethanol at a competitive price — though several facilities are scheduled to go into operation this year.
“I say this with sadness,” said Murthy. “But it doesn’t really matter how much we talk about green, if it costs more at the pump it’s not going to fly.”
So like Lewis, many scientists and entrepreneurs are searching for better ways to turn plants into products. A company called NatureWorks is already producing biodegradable plastics from chemicals extracted from corn. British scientists hope to gain approval for field trials of flaxlike plants engineered to produce the omega-3 fatty acids found in fish oil. The researchers say plant-derived fish oil would be more sustainable and less environmentally damaging than harvesting vast quantities of small fish to extract the oil.
Poplars are an appealing species to work with, because they grow up to 10 feet a year, Lewis said. Young trees can be mowed down like grass, and will resprout, with fields yielding two crops a year.
They can also be grown on marginal land, so the tree farms won’t compete with food production for prime locations.
Lewis hopes the rose-scented chemical will be the first of many he and his team can coax their trees to produce. Under the Elasid banner, they’re already scouting out a location for a commercial-scale operation. But first — in addition to finding money, getting federal approval and juggling all the other challenges of a startup — they have to make sure results from the lab will translate to the field.
“That’s where the proof of the pudding is,” Lewis said.
Sandi Doughton at: 206-464-2491 or email@example.com