Lignin expert chooses to pursue biofuels research at UW-Madison
Most scientists can’t help but daydream about their research projects, which is why you’ll often find John Ralph doodling on restaurant napkins. The University of Wisconsin–Madison professor of biochemistry often interrupts his meals with a quick sketch, usually depicting some piece of the structure of lignin, the subject of his research for the past 36 years.
But amid deepening concern over the world’s dependency on oil, Ralph’s napkin art might turn out to be as valuable as a rare Rembrandt. Lignin — a tough, glue-like substance that keeps plant cell walls from falling apart — presently stands as one of the chief barriers to making fuel from grasses and woody plants, which most experts see as a preferable alternative to ethanol made from corn kernels or other food sources. And few people in the world know more about lignin than Ralph, who until earlier this year was a scientist with the U.S. Dairy Forage Research Center at UW–Madison.
During the past year, the affable New Zealander has been the subject of an intense bidding war among the three bioenergy research centers created last year by the U.S. Department of Energy, including UW–Madison’s Great Lakes Bioenergy Research Center (GLBRC). Ralph recently accepted an offer to join the GLBRC team, which means he’ll now work full-time on achieving the holy grail of plant-based fuel.
UW-Madison is betting that Ralph’s intricate knowledge of plant cell walls will expose new ways of engineering plants that are easier to convert into ethanol. Although the technology already exists to do that, the process is energy-intensive and inefficient, which is why so-called “grassoline” has yet to emerge as a viable alternative to petroleum-based fuels or ethanol made from corn kernels.
A major problem is that the two types of energy-rich components found in biomass — cellulose and hemicellulose — tend to get tangled up in a sticky web of lignin during processing. What is needed, and what Ralph is pursuing, is an easy way to remove lignin so that these long chains of sugars can be extracted from biomass, turned into simple sugars and converted to ethanol.
“We are (developing the technology) to redesign an agricultural plant so that its lignin falls apart easier to make the production of ethanol much more efficient,” says Ralph. “If we get this figured out, there is the potential for a huge reduction in the cost of ethanol.”
Ralph has been studying the chemistry of plant cell walls since he was 18, when he took a forest-service internship in his native New Zealand. He joined the federally funded Dairy Forage Research Center in 1988, which also gave him an unpaid teaching and research appointment in UW–Madison’s forestry department. For the next two decades, his group gradually perfected techniques for visualizing the components of plant cell walls using nuclear magnetic resonance spectroscopy (NMR), which allows scientists to determine the structure of chemicals in fine detail.
“You need to know the structure of the plant cell wall so you can figure out how to break it down, what it’s doing in various processing treatments and which treatments are effective or not,” explains Ralph.
A breakthrough from Ralph’s group, which was announced last year, has reduced the time it takes to analyze plant samples from one month to less than a day, and is expected to speed the process of testing and engineering plants with faster-degrading lignin. It also turned Ralph’s group — a three-person team that includes scientists Fachuang Lu and Hoon Kim — into a coveted asset: Within months of announcing the new method, the trio was being actively recruited by various institutes including the DOE-funded centers located in Berkeley, Calif., and Oak Ridge, Tenn.
Because Ralph’s previous appointment was funded by the U.S. Department of Agriculture, he was technically ineligible to work with UW–Madison’s own bioenergy group, the GLBRC. But administrators in the College of Agricultural and Life Sciences quickly assembled a counteroffer that included a faculty position in the biochemistry department, allowing him to participate in GLBRC-sponsored research, which Ralph says was a significant factor in deciding to stay.
“People with John’s training, experience and creativity just do not exist in this country or elsewhere in the world,” says Tim Donohue, GLBRC director and professor of bacteriology at UW–Madison. “It was critical to get John’s research team plugged into the Wisconsin bioenergy effort. One only need look at the number and type of offers he was getting at other places to see his unique talents in chemistry and plant biology. By keeping John as a member of the Madison bioenergy research community, the campus, state, region and Great Lakes Center are positioned to maintain leadership in the emerging field of cellulosic biofuels.”
Ralph likes how the GLBRC “has brought together a lot of researchers who have never worked together before.” And now that he’s one of those researchers, he is continuing to develop and perfect ways to deal with lignin in the bioconversion process. He plans to keep working on a promising project that he and his former colleagues at the Dairy Forage Research Center hit upon: a way to alter lignin so that it “unzips” under mild processing conditions. “Plants need lignin, so the idea is to let the plants make lignin,” says Ralph. “But (let them) make it the way we want it, not the way they usually make it.”
In the lab, the idea works. The group’s altered lignin allows the plant biomass to release up to 70 percent more fiber — cellulose and hemicellulose — than with regular lignin, and it does so at lower temperatures. The group is currently collaborating with a South Carolina biotechnology company called ArborGen to create trees with this type of alteration, in the hopes that these fast-growing trees will become the major feedstock for a new and better biofuel.
