Photo: Bryan Sims, BBI International
August 1, 2011
BY Bryan Sims
Algae may be garnering the most attention as a viable third-generation feedstock for biodiesel production. As Gary Breitenbeck, professor in the School of Plant, Environmental and Soil Science at Louisiana State University’s Agricultural Center, and chief science officer for CTT BioEnergy LLC, explained to attendees at the Energy Environmental Research Center’s Biomass '11: Renewable Power, Fuels and Chemicals Conference in Grand Forks, N.D, producers shouldn’t overlook the tallow tree for its equal, if not superior, benefits as a potential methyl ester feedstock.
Introduced in the U.S. by Benjamin Franklin, Breitenbeck gave a brief historical introduction about how the tallow tree had been an important oilseed crop in China for more than 1,500 years and how the Chinese have used tallow to produce lipids for soaps, illumination oils, waxes for candles and oil for lighting. “They even pay their taxes with it,” Breitenbeck said. “It’s worth more than rice.”
Currently, the tallow tree is a perennial crop that can be found spread across much of the Southeast between Texas and North Carolina, according to Breitenbeck, and grows on land unfit for agriculture. Additionally, the tallow tree has virtually no insect problems, is fast-growing, has the capacity to sequester large quantities of carbon and can produce 25 to 40 times more oil per acre than soybeans.
Although typically planted as an ornamental for years in the Southeast, Breitenbeck discussed how he and his colleagues at CTT BioEnergy are now focused on developing ways to commercialize the tallow tree and introduce it as a biodiesel feedstock.
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According to Breitenbeck, the tallow tree can yield approximately 12,500 pounds of seed per acre that contain about 300 gallons of kernel oil, 2,500 pounds of tallow wax, 1,350 pounds of meal and 5,000 pounds of seedcoat. He also alluded to a study conducted in the 1980s that found seed yields between 3,500 and 8,900 pounds per acre per year with sustained lipid yields of about 1,000 gallons per acre per year.
“This is breathtaking,” Breitenbeck said. “This is almost like the values they publish on the Internet for algae.”
Breitenbeck noted two unique characteristics of the tallow tree’s lipids that make it different than other nonfood oilseed crops. One is the outer coating of the seed that contains two-thirds palmitic acid and one-third oleic acid. The other is that the kernel oil primarily consists of unsaturated 18-carbon waxes such as oleic, linoleic and linolenic acids.
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“Together, the whole seed can be extracted and be converted into a very satisfactory biodiesel,” he said.
Despite the numerous advantages the tallow tree holds as a biodiesel feedstock, Breitenbeck said that CTT BioEnergy is working on controlling invasiveness, among other issues. “This thing has to be tamed,” he said. “It’s still a wild beast right now.”
He added, “We believe the tallow tree has the potential to become our most energy efficient and profitable oilseed crop. It also has the ability to restore economic viability in some of the most impoverished areas in the South where agriculture and forestry have died.”
In addition to controlling its invasiveness, Breitenbeck discussed how CTT BioEnergy is addressing several other challenges such as germplasm development, cultural practices, improving harvesting, processing and marketing before introducing the tallow tree as a commercially available oilseed feedstock for biodiesel production.