Of Mice, Men and in situ

The means already exist for the production of biodiesel using low-value corn oil extracted from the back end of an ethanol plant. If science was content with existing technologies, however, we'd all be reading by candlelight and salting our meat well before we planned to eat.
By Ron Kotrba | March 27, 2007
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White laboratory mice are integral to advancing biomedical science partly because they're a proving ground to gauge the positive and negative effects of pharmaceuticals on diseases. These mice are subject to routine blood sampling, which researchers say can be difficult and inhumane: Bloodletting from the eye, clipping off the end of the tail or drawing from a cheek are morbid, yet common, ways of extracting blood from a mouse. Scientists of the USDA Agricultural Research Service (ARS)—William Golde, Peter Gollibin and Luis Rodriguez—developed a practical and humane way of retrieving blood samples from mice. The "Goldenrod" lancet, aptly named after its three inventors, elevated from concept to commercial success quickly, compared with most research projects—a success only one in a thousand achieves. "I think it's fair to say—and you could go to 3M, Bell Technology, or even to some of the pharmaceuticals like Lucent Labs—one in a thousand research ideas move forward to commercialization," says Jerry Crawford, technology transfer coordinator with the ARS in Philadelphia.

Inventors of the Goldenrod, modeled after lancets used for humans, asked a brilliant yet fundamental question: If it works on humans, why not on lab rats? The irony here goes without mention, but a private company latched onto the idea through the ARS and went to market with a refined product. More than a million units were sold the very next year. Speaking to the degree of success this rare gem attained, Crawford says, "It's unusual, yes, but it happens."

Whether a research concept will be a commercial success or not is undeterminable unless work is done to prove or disprove theoretical suppositions, conditions of which change. "Success often depends on timing," Crawford says. The following story is a look at a research concept—producing biodiesel directly from the fats and oils found in agricultural materials without having to isolate them ahead of time. The concept has potential for commercial applications in many parts of the biodiesel industry. Some may be more economically feasible than others. Still in its developmental infancy, only work and the future will decide its fate.

Inception of a Concept
With all due respect to ethanol, Mike Haas is a biodiesel man. He is also a respected research biochemist with the ARS and a past president of the American Oil Chemists' Society (AOCS). Biodiesel is a renewable fuel made from animal fats or vegetable oils for diesel-burning engines. It's made when fat molecules, known as triglycerides and consisting of three long-chain fatty acids attached to a glycerol molecule, are transesterified in a reaction with excess alcohol (methanol usually) and a catalyst such as sodium or potassium hydroxide, producing fatty acid methyl esters (FAME)—biodiesel. The glycerin is displaced by the reaction and separated, and then the fuel is washed and dried. The excess methanol and catalyst is recovered for reuse.

Haas and a team made up of research leader Bill Marmer, lead scientist Tom Foglia and technician Karen Scott developed a method of biodiesel production that cuts out the expensive intermediary. "We started with the observation that most biodiesel is made from a rather finished agricultural material—fats and oils—and we asked, 'Would it be possible to consider the original agricultural material, say a flaked soybean, as a source of triglycerides that could be converted to fatty acid simple esters by direct transesterification?'" Haas says. In other words, consider the lipid source as a reservoir of the feedstock for biodiesel. In situ transesterification utilizes the original agricultural component as the source of triglycerides for direct transesterification, therefore attempting to reduce the cost of biodiesel production by eliminating the hexane extraction process. The name in situ is a Latin term "meaning in place."

"Oftentimes the best ideas come when you can get out of the hustle and bustle of a lab and just innovate," Haas says, remembering an off-site meeting when he first considered this approach. Through lab testing and time, it was later realized that the method works with virtually any lipid-bearing material. "My core mission is to make biodiesel less costly, and to make processes that will have relevance to the real world," Haas tells EPM.

Another Way to a New Fuel
In addition to studying soybeans, canola and meat-and-bone meal as substrates, the extraordinary amount of ethanol production coming on line—and a discussion with his cousin in the ethanol business—led Haas to inquire whether distillers dried grains with solubles (DDGS), which he says contains about 9 percent oil, would also make a good lipid source for in situ transesterification. There are companies that already offer oil extraction equipment and services based around centrifuging whole stillage, for example, which removes most—not all—of the oil prior to drying the DDGS. In the lab, Haas discovered that DDGS can be reacted with the base catalyst and an excess of alcohol to make biodiesel under ambient temperatures and atmospheric pressures. Moreover, the lab reaction went to near-theoretical-maximum transesterification, suggesting this method could more fully utilize all of the oils. "I view the virtually 100 percent transesterification achieved with the in situ method as an advantage in that regard," Haas says.

Biodiesel consultant Larry Sullivan of Delta-T Corp., a process technology and engineering company servicing the ethanol industry, looked differently at this approach. While Haas recognizes the economic need to still produce a marketable grains product once biodiesel has been made from the DDGS, Sullivan isn't convinced this can cost-effectively be achieved at a commercial scale. "What you have is the dog's breakfast," he says, meaning that the post-transesterified substrate would be a mixture of 35 percent solids and 65 percent liquids consisting of grains, biodiesel, methanol, catalyst, glycerin, soaps and more. "We respect Dr. Haas and where he stands in the biodiesel industry, but this exercise got complicated real fast," Sullivan tells EPM. "We at Delta-T are aware, however, that people want to recover this low-cost oil." Haas isn't convinced of cost competitiveness yet either but notes that his lab has had good success in the inexpensive removal of biodiesel and contaminants from the meal exiting transesterification, and that further work remains to be conducted to fully develop and assess the process. He does point out that the driver for considering it, however, is that a 50 MMgy ethanol plant produces enough DDGS annually to yield 3.3 MMgy of biodiesel via in situ transesterification.

When centrifuged from stillage by existing methods, the corn oil recovered can contain high amounts of free fatty acids, which if reacted with a conventional base catalyst would produce soaps. Experts say oil from the stillage that has been subject to higher temperatures during the ethanol cook process requires pretreatment such as degumming and acid esterification prior to base reaction. Haas' laboratory experiments yielded neither soaps nor gums in the ester product. The former likely either stayed in the DDGS after the reaction or partitioned into the glycerol coproduct phase, and the latter has been shown to transesterify in the process. The FAMEs were similar in fatty acid composition to refined corn oil esters.

Distillers wet grains could also work, which would eliminate the drying process. However, an unrealistic amount of alcohol would be required. In fact, the already high alcohol requirement leads to high costs to recover it for reuse, and forms the biggest obstacle in this approach to making biodiesel, according to Haas. That remains the case even when partially dehydrated DDGS with moisture levels of 8 percent or 9 percent are used. "The typical ratio of alcohol to oil in biodiesel production from oil is two moles of alcohol per one fatty acid mole—or six alcohols per triglyceride," he says. Original in situ tests on soybean flakes were found to require over 500 moles of alcohol per triglyceride for a near-complete reaction. The beans had 7 percent moisture.

Subsequent work demonstrated that moisture levels had a large impact on the amount of alcohol required. By drying the beans to less than 1 percent water, the alcohol requirement fell by 60 percent, plus there was a significant drop in the amount of alkaline catalyst needed. In recent work, Haas and his team have determined that by changing the manner in which the feedstock is prepared for reaction and by switching from batch to continuous mode for the reaction, it's possible to achieve even further reductions in the alcohol requirement of the reaction. Research has also shown that the process works well with ethanol. Because the ethanol molecule is larger than methanol, a higher volume of ethanol is required.

As with soy flakes from which the oil has been removed, DDGS are primarily used today as animal feed. Haas is aware of the fact that the new process will have little future unless the meals exiting in situ transesterification are also acceptable as animal feeds. Importantly, lab analyses have shown that protein is not removed from the substrate when it is subjected to in situ transesterification. To date, two feeding trials have been conducted to address the question of whether this protein is nutritionally available to animals. In one preliminary examination using chickens, a group of five birds accepted a diet containing transesterified soy flakes and grew just as well as a companion group receiving standard fat-free soy flakes. In another larger study conducted in collaboration with the USDA-ARS Fish Culture Experiment Station in Hagerman, Idaho, trout also accepted transesterified soy flakes with their diets and performed comparably to fish on a control diet.

"It's like a trout-farm haven out there," Crawford says. "In this study, we saw no decrease in weight gain or growth of the trout."
Once he was made aware by colleagues at the Agricultural Utilization Institute of Minnesota about the flow and compacting problems that can plague the handling of DDGS, Haas collaborated with that organization to examine the flowability of DDGS that had undergone this process. It was found that these completely lacked the problems characteristic of full-fat DDGS.

Haas points out that with so many potential feedstocks on which to explore the in situ transesterification approach, he has taken the tact of demonstrating the feasibility of the reaction on any particular material and then sees if the private sector shows sufficient interest to jointly take the work to a larger scale. Partners for process and feeding trials are sought by the ARS to fulfill whatever role destiny has planned for this unconventional approach to biodiesel production. Interested players should contact Jerry Crawford at (215) 233-6610, or Michael Haas at (215) 233-6459 for more information.

Despite Sullivan's respectful and knowledgeable critique of transesterifying whole DDGS, and Haas' own cautions about this emerging technology, enough about the in situ method in this application is not yet known to determine how it will fare in competition with other back-end extraction methods. "Technology transfer and adoption of new technologies is always a big hurdle," Crawford says. "But obviously we're doing things differently than we did 20 years ago, so some people and companies are willing to take the risk of partnering to explore and develop new technologies in the laboratory for technological advancement. Those are the people we're looking for."

Ron Kotrba is an Ethanol Producer Magazine staff writer. Reach him at rkotrba@bbibiofuels.com or (701) 746-8385.