Researchers investigate uses for biofuel byproducts

The baking tins lining the counter tops in a corner of Ronald Holser’s cluttered laboratory were filled with curious substances resembling cakes and loaves of bread. The concoctions were prototypes for biodegradable weed barriers and sticky films intended to hold grass seeds on the ground long enough to germinate.

If Holser, a research chemist, and his colleague Steven F. Vaughn, a plant physiologist, are successful, they will have found more than ecologically friendly ways to fight weeds and grow grass. They will have found innovative uses for a byproduct of the production of biodiesel fuel, glycerol. This, in turn, could help transform the biodiesel industry into something that more closely resembles the petroleum industry, where fuel is just one of many profitable products.

Glycerol is used in a variety of products, including foods, soap and dynamite. But as biodiesel fuel production in the United States has risen, the market for glycerol has become saturated.

If scientists like Holser and Vaughn can expand the number of valuable uses for the syrupy liquid, biodiesel makers could sell their glycerol instead of paying someone to haul it away. "Every week I get at least one or two calls from biodiesel producers who have all this glycerol and don't know what to do with it," Holser said.

Glycerol, also called glycerin, is not the only byproduct of biofuel production that is the subject of experiments. Scientists are also looking at profiting from the leftovers from the production of corn ethanol and cellulosic ethanol, made from materials like switch grass, corn husks and prairie grass. Around the US, scientists, entrepreneurs and venture capitalists are becoming increasingly interested in making more than fuel out of the raw materials for biodiesel fuel and ethanol.

Some researchers, like Holser, are simply trying to find new uses for the regular byproducts of biofuels : distillers' dry grain from corn ethanol and lignin from cellulosic ethanol. Other researchers are trying to develop technologies and processes that could yield different, more valuable byproducts. And still others are placing their bets on "biorefineries."

In Colorado, PureVision Technology is making lignin, a natural compound that helps provide strength and rigidity in plants and makes up 15 to 25 percent of most plants. Most plans for cellulosic ethanol processing call for burning the lignin to generate steam and heat to run the process. As a fuel, lignin is worth around $40 a ton. PureVision has devised a way to make a different form of lignin; one with a molecular composition that could make it an attractive material for a variety of industrial products like glues, sealants and detergents.

Ed Lehrburger, PureVision's founder and chief executive, said he thought his lignin could sell for $300 a ton or more. He said his company was collaborating with a wood and paper products manufacturer that is interested in using the lignin for a bio-based glue for its laminates, plywoods and other products. "Lignin is going to be one of the big drivers of the switch from oil-based to bio-based products," he predicted.

In Ames, Iowa, Victor Lin has created a technology that changes the production process for biodiesel. Among other attributes, his invention yields a higher quality form of glycerol, which could be more easily converted into useful industrial materials.

The production of biodiesel fuel requires a catalyst. Dr. Lin created a catalyst that is safer and easier to use than the one commonly used now, reducing the cost of producing biodiesel and its impact on the environment (requiring less water, for instance). Lin and his colleagues are trying to turn the resulting glycerol into a substance called 1,3 propanediol, or PDO, the base material for a substance used in upholstery, carpets, clothing and other applications.

"For every gallon of biodiesel you make, you make a pound of glycerol," said George Kraus, a professor of chemistry at Iowa State and a collaborator of Lin. "A lot of people have been contacting us about burning it, and we say there have to be better uses."

The price of glycerol, now 20 to 50 cents a pound, could drop as low as 5 cents a pound as biodiesel production increases. Kraus said the higher quality glycerol made with the new process could command a much higher price.

In another lab at Iowa State, Robert C. Brown is using distillers' dry grain, a main byproduct of corn ethanol that is largely sold as animal feed to produce hydrogen and a compound called PHA. Brown hopes his version of PHA, which is biodegradable, could be used for surgical gowns and gloves that must now be disposed of as medical waste.

"Critics of corn ethanol like to say the process isn't very efficient," Brown said. "Part of that is because your products aren't just fuel. Finding other high-value applications, he added, lets producers justly say, "this is not a waste stream; it adds to the profitability of the plant."

But despite the many uses for byproducts, the biorefinery model is more difficult than it may seem.

"The dream is the multiproduct biorefinery," said Jim McMillan, manager of biorefining process research at the National Renewable Energy Laboratory in Colorado. The challenge is that the market for the fuels is like two orders of magnitude bigger than for even a fairly big chemical that could be produced alongside the fuel.

NYTimes