The Quest to Commercialize Biobased Succinic Acid

High-priced petroleum brings the finite nature of this resource to a striking reality. Out of necessity comes research into alternative fuels and the myriad of materials made from petroleum. Since the mid-1990s, succinic acid has garnered interest as a petroleum alternative for the manufacture of everything from de-icers to pesticides.
By Jessica Ebert
In 2004, the U.S. DOE released a report identifying 12 chemicals that could be produced from sugars, most through microbial fermentation. These building blocks were of interest because they could be converted into various high-value biobased chemicals and materials. At the top of the list was succinic acid, a four-carbon molecule with a chemical structure similar to maleic anhydride. Maleic anhydride is a petroleum-derived substance that provides a chemical feedstock for food and pharmaceutical products, surfactants and detergents, plastics, clothing fibers, and biodegradable solvents. Because the two chemicals are so much alike and succinic acid is made by all living things through a natural fermentation of sugars, biomass-derived succinic acid could serve as an attractive replacement for maleic anhydride and a platform chemical for the synthesis of a multitude of compounds. "That is the beauty of succinic acid," explains Susanne Kleff, senior scientist for MBI International, formerly Michigan Biotechnology Institute. "First you want that four-carbon platform," she says. "Second, any chemical you can make that is part of the central metabolism of an organism always implies that you can make lots of it and that you can make it easily." Although currently elusive, a competitively priced route for the "green" production of succinic acid could open a menagerie of new markets for the chemical.

Much of the research into biobased succinic acid originated in government agencies, particularly the DOE, however, the attention of these institutions is now consumed with meeting fuel standards. "Some government agencies' emphasis on biobased products has lessened because of more pressing energy and fuel mandates," explains Gene Petersen, DOE project officer and chemist. "The question is will the private sector step up to the plate?"

The answer is yes, say representatives from two companies who agreed to speak with Biomass Magazine about each company's quest to make competitively priced, biobased succinic acid a reality.

The Prize
As quests go, this one may not be as dramatic as destroying a ring and ridding war-torn Middle-Earth of a supernatural evil as in the "Lord of the Rings" epic. However, the eventual reward reaped by the potential heroes-a market estimated at more than $1.3 billion per year-is not too shabby a prize for overcoming the challenges to commercialize the means to produce green succinic acid. Although currently available succinic acid, which is made from butane, a four-carbon petrochemical, serves a relatively small world market of about 15,000 metric tons per year, the potential market for a biobased form of the chemical could be well over 100 times that amount. "The extent of market penetration depends mainly on the price competitiveness of biobased succinic acid relative to the petrochemical alternatives," Kleff says. "There is also more interest in producing polymers from monomers produced via a green route."

The bounty from this potential gold mine lies in the usefulness of succinic acid as a building block for a plethora of secondary chemicals. Kleff outlines three major potential markets for green succinic acid. The greatest of these is as a biobased replacement for maleic anhydride, which currently serves a global market of about 1.65 million tons per year. Second is the more than 1.6 million pounds per year global market for polymers currently derived from butane. The smallest market of about 100 million pounds per year is for pyrrolidinones, which are used to make green solvents and eco-friendly chemicals for water treatment.

"There are all kinds of derivative markets where right now succinic acid is not used because it's too expensive compared with petrochemicals," explains Dilum Dunuwila, vice president of business development at Diversified Natural Products Inc. (DNP) an industrial biotechnology company. "As a business we have to get to the point where we are economically competitive with petrochemical pricing," he says. "We are getting there."

The final prize and incentives for action are well defined but how will they be achieved?

The Journey
MBI, established in 1981 by the Michigan High Technology Task Force, has a history of developing biobased chemicals and agricultural feedstocks into chemicals derived from fermentation processes. In 1996, the company patented the unique bacterium it isolated for production of succinic acid from sugars. MBI scientists-knowing that the rumen, one of the four compartments of the bovine stomach, was a warm, voluminous holding vat devoid of oxygen and brimming with microbes that digest and ferment an endless supply of well-masticated feedstuffs-collected rumen samples and isolated a novel succinic acid producer. "The rumen is an environment where you would expect to find an organism that produces succinic acid," Kleff explains. In addition to conditions prime for fermentation, "the environment is high in carbon dioxide, which we incorporate into our product," she adds. "So, in contrast to almost everything else other than photosynthesis, we make a product in which we incorporate CO2 (carbon dioxide)." Because carbon dioxide is a byproduct of ethanol production, the synthesis of biobased succinic acid could be linked to ethanol plants.

The biggest challenge thus far for the MBI team, other than working with a microbe that was unknown at the time, was determining how to recover succinic acid from the fermentation broth, Kleff explains. "In contrast to alcohols, which you can just distill away from your other components, you cannot do that with succinic acid," she says. For the last 10 years, MBI researchers have characterized the bacterium, dubbed Actinobacillus succinogenes, identified the microbe's optimal growth conditions and fermentation products, and optimized methods to improve the strain, minimized byproducts, maximized the yield and purity of succinic acid and recovered the molecule. "Our research has been focused on strain- and fermentation-process improvements, on recovery methods and on integrating the process package for robust and economical production," Kleff says.

At this point, MBI has scaled-up the bench-top fermentation process for the production of succinic acid to a 1,000-gallon fermentation process at its pilot plant in Lansing, Mich. "When you make it to that stage you've passed a lot of hurdles," Kleff says. However, this is not the size that could supply the market with significant amounts of biobased succinic acid, she says. To that end, MBI has partnered with another company to commercialize the technology. No further details about this partnership were available at press time.

A second company that is moving toward large-scale production of biomass-derived succinic acid is DNP, formerly Applied CarboChemicals. Through licenses, the company has acquired the intellectual property to transform crop-based sugars into succinic acid, Dunuwila explains. Like MBI, DNP's process for making succinic acid starts with a microbial fermentation. However, DNP uses a strain of Escherichia coli developed at the DOE in the mid-1990s as part of the agency's Alternative Feedstocks Program. Under normal conditions, "E. coli ferments sugars to produce a mixture of acids," Dunuwila explains. "However, DOE's efforts led to a bug that is optimized to produce succinic acid and only a minimum amount of byproducts."

DNP has also developed methods for separating and purifying the succinic acid. Dunuwila explains that one of the biggest challenges his team has encountered in terms of separation is that compared with petrochemical feedstocks, which are concentrated, the fermentation output from biobased processes is very dilute. "Processing that dilute stream economically to produce succinic acid can be a challenge because of the energy required to get rid of all that water," Dunuwila says.

Currently, DNP, along with its French partner Agro Industrie Recherches et Dèveloppements (ARD), has a research and pilot facility in Pomacle, France. Here, the company's technologies are being optimized to make them more economically viable by minimizing byproducts and waste, and maximizing output. By late-2008 to early-2009, the two companies plan to bring a 5,000-metric-ton demonstration plant on line. Although this capacity is no where near what the eventual market would be, "In part, our goal for the demo plant is to show that we can economically produce succinic acid," Dunuwila says. In addition, "the demonstration plant will give us an opportunity to provide samples for testing and establish business relationships to help us move forward toward building large-scale plants worldwide," he says.

"There are several companies and institutions active in biobased succinic acid [research and development]," Dunuwila says. "But as far as we know, DNP along with ARD is the only group that has announced the construction of a production-scale plant. In terms of technology, I think we are the furthest along in the quest for commercializing succinic acid."

So there it stands. Our heroes may not be wielding swords, clubs, or bows and arrows but the pipettes and bacterial cultures they brandish seem to leave them well-quipped with the tools, knowledge and wherewithal needed to bring the journey to commercialize succinic acid to a promising end-or to another beginning perhaps?

Jessica Ebert is a Biomass Magazine staff writer. Reach her at or (701) 746-8385.

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