Gasoline is expensive, growing scarcer, and a suspected contributor to climate change. Ethanol derived from corn and other grains is a limited resource, and has caused concerns about using food for fuel during a time of global overpopulation. The best solution, some scientists say, lies in creating ethanol from the cellulose in non-edible material like corn stalks, wood chips, switchgrass, and even paper pulp. The process is expensive, but recent breakthroughs have raised hopes that these ‘biomass’ resources could eventually be the abundant, clean-running, and economically viable answer to the world’s fuel needs.

Switchgrass is a hardy prairie grass that can grow quickly to heights of two to six feet during the warm months of the year.

It’s self-seeding, is resistant to many diseases and pests, and produces high yields. It also improves soil and prevents erosion, which is why it’s approved as a cover crop for land protected under the federal Conservation Reserve Program. And it grows practically anywhere.

Oh, and it’s rich in cellulose.

That makes it one of several promising non-edible plant materials being closely examined by proponents of cellulosic ethanol, a potential fuel source produced from the cellulose of switchgrass, wood chips, leaves, corn cobs, corn stover (what’s left of the plant after harvest), and dozens of other sources, known collectively as ‘biomass.’

“I’m passionate about working in this field, working to develop this technology,” said Susan Leschine, a professor of Microbiology at UMass Amherst, and one of several science and industry experts who recently presented a day-long seminar on campus focusing on the promise and challenge of cellulosic biofuels.

“It’s now accepted that fossil-fuel combustions are leading to the climate change we are experiencing,” Leschine asserted. “As we meet our energy needs, we must determine how we’re going to deal with greenhouse gases using the types of infrastructure we already have, and in a reasonable time frame.”

The first wave of biofuels, most notably corn ethanol, have shown promise, but have also sparked debate over competing uses of corn for food versus fuel — and led to the realization that the amount of ethanol derived from grains will plateau at between 12 billion and 15 billion gallons per year, a small dent in the 140 billion gallons of gasoline currently consumed in the U.S.

Biomass feedstock sources — forest growth and byproducts, perennial crops like switchgrass, paper pulp, and more — are almost by definition plentiful and renewable, and have the potential to supply 35% of U.S. fuel demand, said Michael Ladisch, professor of Agricultural and Biological Engineering at Purdue University.

“That’s a big number, and it would help our balance-of-trade payments, 75% of which are due to oil. We spent $500 billion last year on importing oil, so there are other issues involved as well,” he noted — not the least of which are the geopolitical challenges of relying so heavily on governments that aren’t necessarily friendly to U.S. interests.

But while biomass sources are far more abundant than grain-ethanol sources, the cost to convert them to fuel are more expensive. “The costs are the key impediment,” said Leschine. “It’s all about economics.”

But breakthroughs are being made — some of them right on the UMass campus — that give proponents of cellulosic biofuel hope that some of the world’s most abundant resources can eventually replace increasingly problematic fossil fuels.

Q and A

One of those breakthroughs is something dubbed the ‘Q molecule,’ which is a little less clunky than its actual name, clostridium phytofermentans. The ‘Q’ represents the Quabbin Reservoir, where it was first discovered about a decade ago.

Essentially, the microbe has a huge appetite for plant material and other forms of cellulose, even recycled paper, and has proven it can break that material down into ethanol — at least in the lab. The challenge is to determine whether this performance can be scaled up to produce ethanol on a large scale — say, millions and billions of gallons.

Leschine is also chief scientist at SunEthanol, a Hadley-based venture launched by entrepreneur Jef Sharp. The company recently won a federal grant to further its work with the Q microbe, part of an ongoing, multi-pronged financial commitment by the Bush administration to work toward the president’s stated goal of 21 billion gallons of advanced biofuels to be used in the U.S. annually by 2022.

By any estimate, grain-based fuels can’t meet that need, so the development of cellulosic biofuels clearly must be part of the picture.

To understand what the Q molecule does, it’s necessary to grasp the steps required to turn biomass into fuel. First is a ‘pre-treatment’ phase to make the biomass material amenable to hydrolysis, followed by cellulose hydrolysis (cellulolysis) to break down the molecules into sugars. The final phases are separation of the sugar solution from the residual materials, notably lignin; microbial fermentation of the sugar solution; and distillation to produce 99.5% pure alcohol.

The pre-treatment is crucial because, although cellulose is the most abundant plant material, its rigid cellular structure makes it useless as a fuel source until it is ‘liberated’ from its own walls and rendered accessible for the hydrolysis step.

This may be accomplished in one of several ways, such as acid hydrolysis, steam explosion, ammonia fiber expansion, and alkaline wet oxidation, to name a few. Many of these techniques pose their own problems, including production of toxic inhibitors — and all increase the cost of cellulosic biofuel production.

“You can’t just put a log into the fermenter,” Leschine said. “You have to pre-treat it. The molecules must be broken up and exposed to the activity of enzymes.”

Much of the excitement around the Q molecule is its potential to cut down on the cost of creating cellulosic ethanol by naturally pre-treating the biomass. By combining the breakdown and fermentation in a single stage, the process could bring down costs and make biomass more economically feasible. “What we have here,” she further explained, “is a biocatalyst that has a voracious appetite for plant polysaccharides.”

Getting Warmer

Clearly, the economics of turning biomass into fuel present both pros and cons. On one hand, corn is less expensive to process into ethanol than cellulose is; in fact, the U.S. Department of Energy currently puts the cost of cellulosic ethanol production at $2.20 per gallon, about twice that of corn ethanol. The enzymes needed to destroy plant wall tissue cost 30 to 50 cents per gallon of ethanol, compared to 3 cents per gallon for corn.

However, cellulosic biomass itself is cheaper to produce in crop form than corn because it requires less in the way of energy, fertilizer, and herbicide, and it produces less soil erosion.

In addition, the solids left over from converting biomass to fuel can be burned to provide the energy needed to operate the conversion plant. Corn-based ethanol plants typically require coal or natural gas for their operation, meaning the creation of cellulosic ethanol reduces greenhouse-gas emissions compared to corn ethanol.

Meanwhile, when used as a fuel, cellulosic ethanol releases less sulfur, carbon monoxide, particulates, and greenhouse gases than corn ethanol does — and around 90% less than burning gasoline.

To answer such challenges and bridge the gap between scientific potential and economic reality, UMass recently launched The Institute for Massachusetts Biofuels Research (TIMBR), which consists of 26 faculty members from 10 academic departments, from Engineering and Chemistry to Economics and Environmental Sciences, and which sponsored the recent seminar.

“We feel all these groups have a particular expertise that’s relevant to overcoming major hurdles in bringing biomass to biofuels,” said Danny Schnell, Professor of Biochemistry and Molecular Biology at UMass.

“The emphasis is on bringing this group of people together within the college environment to foster engineers talking to biochemists and microbiologists, and being informed by those interested in the economics and sustainability of the process.”

UMass should be well-positioned to take a lead role in the national biofuels discussion, he continued, not only because of the expertise on campus and the work (such as with the Q microbe) that has already been accomplished, but also because of geography.

Simply put, most of the established efforts to turn corn into fuel are concentrated in Iowa, Illinois, Minnesota, and surrounding corn-growing states — with almost no activity in New England.

Yet, “the development of biofuels technology that does not rely on food crops presents a tremendous opportunity to develop industry in Massachusetts,” Schnell said. “The biomass inventory in the U.S. includes 1.3 billion tons of perennial crops, forest products, and urban waste, and all of those are available here in the Northeast.”

Some TIMBR-related projects have gained national attention. George Huber, assistant professor of Chemical Engineer-ing at UMass, was awarded a grant earlier this year by the National Science Foundation for his work with converting plant matter to ‘green gasoline’ through a process that rapidly heats, then cools the plants to extract hydrocarbons.

“It’s a great field to be in,” said Huber. “Clearly there are unanswered questions at this point in time. We’re trying to make all the components found in gasoline, heating fuel, and jet fuel from biomass.”

Field of Study

Fortunately for believers in biomass, progress in other fields — literally — might bring benefits for their work. Specifically, Ladisch said, an acre of harvested corn now yields 160 bushels of corn stalks, cobs, and leaves, up from 120 a decade ago, with expectations of 300 bushels per acre over the next 15 years — all because of advances in the way crops are planted.

And that doesn’t count 1 to 3 tons of corn stover per acre, or the 5 to 7 tons of biomass that can be culled from an acre of switchgrass. In short, these aren’t resources that are in any danger of running out, and because they’re found across the country, shipping costs could theoretically remain low. “These numbers,” Ladisch said simply, “are very attractive.”

Raw materials won’t run a car engine, however, or heat a home. That’s why work continues across the country to produce cellulosic ethanol in an economically feasible fashion — and why scientists at UMass find themselves fueling some exciting progress.

Joseph Bednar can be reached at bednar@businesswest.com