| | Adding value to sugarcane beyond just use as sugar is the mission of the Audubon Sugar Institute. (Photo by John Wozniak) |
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| | Raw sugar is stored in warehouses before being transported to refineries. (Photo by John Wozniak) |
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| | Sugarcane is taken to mills and unloaded. (Photo by John Wozniak) |
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Adding value to sugarcane has always been the mission of the LSU AgCenter’s Audubon Sugar Institute. But that mission has taken a new twist in these times of high fuel costs. One of newest projects is making ethanol from cane.
The ethanol project is part of a cooperative venture with MBI International, a nonprofit spin-off of Michigan State University, and the Audubon Sugar Institute. The two institutions received two $500,000 grants from the U.S. Department of Energy (DOE) in 2004 and 2005 for funding a four-year project to produce value-added products from bagasse and molasses. The DOE awarded another grant in 2005 for $2 million to fund additional research in sugar-based biorefining. And an additional $1 million was received for the 2006-2007 fiscal year.
The first grant focuses on bagasse, the fibrous material that remains after sugar is pressed from sugarcane. Bagasse is currently burned as fuel in sugarcane mills, but researchers hope to increase the value of what is now considered a waste product. MBI International has a process for treating bagasse and other vegetative residues to convert them to sugars, which can be fermented into ethanol, an alternative to gasoline.
“The focus is adding value to cane biomass,” said Donal Day, a researcher at the Audubon Sugar Institute, which is a facility located off-campus near St. Gabriel, La. “This will allow the processors to get revenue from something other than the sugar. Ethanol from sugarcane is quite feasible, particularly at current prices.”
Ethanol out of biomass changes the historical approach to growing and processing sugarcane. Instead of growing the plant exclusively for sugar, producers could grow sugarcane for the total biomass.
“The leaves and tops are more amenable than bagasse for making ethanol,” Day said.
One advantage of using sugarcane as an ethanol feedstock is that producers already bring most of the plant to the mill for processing, leaving only the leaves in the field. By having the leaves on, the mill would be able to divide the plant, using the leaves for ethanol production, the cane for sugar as they always have and the bagasse both for fuel for running the mill and for additional biomass for making ethanol.
A preliminary analysis shows that an ethanol plant in the Bayou Teche area could produce 62 million gallons of ethanol per year with materials from four area mills. Such use could extend the sugarcane season into the winter by harvesting the cane for ethanol rather than for sugar only. He also said the energy to produce ethanol from sugarcane is less than the energy requirement for producing ethanol from corn.
“The challenge is economics,” Day said. “We can do it in the lab. The technology is there, but the economics aren’t there yet to be commercially viable.”
One advantage of using bagasse as a source of biomass is that it is already being delivered to sugar mills while other products, such as corn stalks, have to be collected. The Audubon Sugar Institute has the capacity to move research from the laboratory to a pilot plant and eventually work with industry to bring the process into full production. If the research proves fruitful, the process could result in establishing a plant that could use $23 million worth of raw products from Louisiana sugar mills to produce products with annual revenues in the range of $265 million. The plant and equipment would require capitalization of around $140 million.
The federal government has targeted agricultural byproducts as resources for energy and is putting up the money to get ethanol off the ground. Sugarcane is an extremely efficient converter of solar energy to biomass, and biorefining can convert bagasse into fermentable sugars that produce higher-level alcohols and organic acids. Day said biorefining can yield a host of value-added products from sugarcane.
The research emphasis at the Audubon Sugar Institute is shifting. “We spend a lot of time looking at biorefining to get more out of sugarcane,” Day said. “We’re looking at a slate of products, and ethanol is one.” Researchers are separating sugarcane plants into different components to make products of value using processes such as enzymatic hydrolysis, which uses water and enzymes to break down the sugarcane into different products.
“We’re trying to move from the laboratory to the pilot plant with a number of projects,” Day said. “We’re considering design data and economic criteria.”
Researchers at the Audubon Sugar Institute also are investigating higher-value products from sugarcane. These include biocides, nutraceuticals and oligosaccharides.
One biocide, which has been patented and licensed, is a cold sterilant with strong oxidizing properties that, though relatively harmless to the skin, kill bacteria and spores from molds and similar fungi. The institute is investigating the use of the biocide as a hospital clean-up sanitizer.
Another product, a nutraceutical from sugar, inhibits the last stage of starch metabolism with no apparent side effects. The result is a reduction of abdominal fat in laboratory tests and the promise of potential antidiabetic effects in humans. Day said the potential health benefits also include poultry production, where the product appears to inhibit salmonella. “It will cost less to make healthy chickens,” Day said. “And, it uses sugar.”
Other products that can come from sugar include oligosaccharides, which can yield such products as mannitol, a compound used in pharmaceuticals, and prebiotic chemicals that can enhance good bacteria and inhibit harmful bacteria in human digestion.
Other research projects at Audubon include:
- Producing synthetic gas from sugarcane biomass.
- Applying microwave technology in sugar processing to improve efficiency.
- Identifying and removing impurities from cane syrups to obtain direct-refined sugar in mills.
Support for the Audubon Sugar Institute comes from the LSU AgCenter and from the American Sugar Cane League. This public-private partnership provides both the financial support and guidance to direct the institute’s activities toward the most important challenges facing Louisiana sugar factories.
“The Audubon Sugar Institute plays a crucial role in the overall success of Louisiana’s 250-year-old sugar industry,” said Jim Simon, general manager of the American Sugar Cane League in Thibodaux. “Our industry has worked cooperatively with Audubon since its inception in 1887. The staff at Audubon provides us with an extraordinary level of talent and experience that is crucial in order for us to continue to be leaders in world wide sugar production.”
The institute has a long and rich history of technical contributions to the modernization of Louisiana’s sugar factories. In 2004, the Audubon Sugar Institute moved from the Baton Rouge campus to St. Gabriel near the LSU AgCenter’s Sugar Research Station. The $5.4 million facility includes a 27,000-square-foot laboratory building and more than four acres of land on River Road. It was formerly the research and development facility of Syngenta Crop Protection, which donated the facility to the LSU AgCenter.
Research projects at Audubon focus on improving efficiency in sugar processing and developing value-added products from sugarcane. The institute also provides expertise to the sugar mills in the state, offers professional development short courses in sugar technology, and provides expertise and laboratory space for courses in sugar engineering through LSU’s College of Engineering.
The LSU AgCenter is one of 11 institutions of higher education in the Louisiana State University System. Headquartered in Baton Rouge, it provides educational services in every parish and conducts research that contributes to the economic development of the state. The LSU AgCenter does not grant degrees nor benefit from tuition increases. The LSU AgCenter plays an integral role in supporting agricultural industries, enhancing the environment, and improving the quality of life through its 4-H youth, family and community programs.