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A Living Plant

DuPont says propanediol is only the beginning of its industrial biotechnology offering

by Alexander H. Tullo
June 25, 2007 | A version of this story appeared in Volume 85, Issue 26

Joint Venture
Credit: Alex Tullo/C&EN
Holliday (from left), Bodman, and Ferguson pose at the DuPont Tate & Lyle plant in Loudon, Tenn.
Credit: Alex Tullo/C&EN
Holliday (from left), Bodman, and Ferguson pose at the DuPont Tate & Lyle plant in Loudon, Tenn.

EARLIER THIS MONTH, executives from DuPont and Tate & Lyle gathered in Loudon, Tenn., to celebrate the opening of a new plant that uses fermentation to make a chemical—1,3-propanediol, or PDO—that had previously been made only via synthetic means.

The ceremony was the public's first look at the new plant and process, which DuPont has been working on since 1993, collaborating with partners Genencor and Tate & Lyle on the project.

In the process, Escherichia coli, modified with genes from baker's yeast and Klebsiella pneumoniae, converts corn-derived glucose into PDO. The 100 million-lb-per-year plant started up last November, based on glucose from an adjacent Tate & Lyle corn milling facility.

Speakers at the event stressed the novelty of using renewable resources to manufacture what was formerly made from oil or natural gas. "Today, we are celebrating a new way to provide for society's needs. We are celebrating the building of a renewable economy," said Steven Mirshak, president of DuPont Tate & Lyle Bio Products.

U.S. Energy Secretary Samuel W. Bodman, who was at the event, said the plant is an important step toward the development of alternative energy sources. "We are hoping to take the vast accumulation of biotech knowledge gleaned in the development of cutting-edge pharmaceuticals and use it in the production of alternative energy," he said. "What you have developed here in Loudon is one example of that idea in practice."

American Chemical Society President-Elect Bruce E. Bursten was at the Loudon celebration to present scientists from DuPont, Tate & Lyle, and Genencor with a 2007 Heroes of Chemistry award.

DuPont and Tate & Lyle expect to sell the plant's entire output because PDO's attributes give it advantages in markets ranging from polymers to aircraft deicers. "1,3-Propanediol has been known since the 1940s as a potential important industrial chemical," Mirshak said. "The problem was the production costs from petrochemical routes were prohibitive."

Even before the Loudon plant opened, DuPont introduced PDO-based products, such as polytrimethylene terephthalate (PTT) fiber, using PDO produced by Degussa via a costly acrolein-based route. Shell Chemicals developed a more efficient petrochemical route based on hydroformylation and opened a 165 million-lb PDO plant in Geismar, La., in 1999.

Mirshak said DuPont's focus is now on selling fermentation-based PDO instead of petrochemical-based PDO. "We have been introducing products over the last couple of years getting ready for this plant to start up," he said. "At this point, we are converting all of our sales to biobased materials."

According to Joseph V. Kurian, technology and business development manager for biobased materials at DuPont, the largest PDO application so far has been PTT-based carpeting. Kurian said an extra carbon in PTT's diol section gives PTT-based fibers more resilience and softness than fibers based on polyethylene terephthalate. In addition, he noted that PTT doesn't have the amine groups or moisture retention that predispose nylon carpets to staining.

DuPont is also launching PTT engineering polymers touted as having properties similar to those of polybutylene terephthalate. Kurian added that the company is exploring packaging applications for PTT, where its barrier and heat-seal properties may make it a good complement to PET in multilayered structures.

The company just introduced a family of PDO-based polyetherdiols called Cerenol. They will be incorporated into polyether-ester thermoplastic elastomers and into automotive primers and clear coats, where they will lend improved flexibility and chip resistance, the company says. Other potential applications for Cerenol include lotions, heat-transfer fluids, polyurethanes, and spandex fibers.

Tate & Lyle's chief executive officer, Iain Ferguson, is already thinking about expanding the joint venture. "It will take another nine to 12 months to get this absolutely up to full capacity," he said. "To expand here would probably be the first thing to do. But over time, there is global potential for this product."

Charles O. Holliday Jr., DuPont's CEO, wouldn't disclose how much PDO has cost his company beyond the $100 million for the Loudon plant. While Holliday joked that more than a decade of R&D work on the chemical has been "too expensive," he said future industrial biotech and biofuels projects will be accomplished faster and more easily thanks to the success of the PDO project.

LAST YEAR, for example, DuPont and BP announced a partnership to develop fermentation-based 1-butanol as a biofuel. Likewise, DuPont and ethanol maker Poet Energy, formerly Broin, are constructing a biorefinery in Emmetsburg, Iowa, by 2009 that will make ethanol from the cellulosic raw material corn stover.

"The scientists that were honored here today are doing biobutanol work," Holliday pointed out. "They built these tools that we patented, and they are using them on cellulose-to-ethanol, biobutanol, and several things we haven't announced yet. It is a lot of up-front investment to get the first product out, but now each new process will get out faster."



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