The Manufacturing Process of Bio-PDO™ and Bio-Based Fibers


By using glucose as the basis for Bio-PDO™, a bio-based monomer, DuPont created a renewably sourced ingredient for bio-based fibers, like DuPont™ Sorona®, which is used in everyday products such as carpet and apparel.

Bio-PDO™ Research and Development

The research into Bio-PDO™ began with a realization by Tim Gierke, Research Manager at DuPont Central Research & Development, that 1,3-Propanediol (PDO) has three carbons, and nature is filled with three-carbon and six-carbon forms. A team of DuPont scientists and engineers collaborated with polymer experts to discuss the possibilities of biological production of PDO. This led to a research project that lasted over a decade, eventually leading to a biological process that would achieve the quantities of PDO needed for a commercially viable product.

Next, DuPont scientists partnered with Genencor scientists to develop the organism that would use the glucose (sugar) from corn starch to produce PDO. They also developed a proprietary fermentation process, followed by meticulous cleaning and distillation, to end up with a pure form of Bio-PDO™.

The next step was to move the process from the laboratory into the real world.

Bio-PDO™ Manufacturing

A $100 million dollar Bio-PDO™ plant was built in Loudon, TN as a joint venture between DuPont and Tate & Lyle.

Railcars full of corn arrive at the Tate & Lyle corn wet mill, where the glucose is produced from the corn starch and then pumped from the wet mill to the Bio-PDO™ production facility.

At the production facility, a micro-organism is added to the glucose. Five nine-story-tall fermentors are filled with the organism and glucose. The organism then excretes Bio-PDO™, forming a broth.

Next, the Bio-PDO™ broth is separated and distilled to a form that is 99.97% pure, with the remainder primarily water. The Bio-PDO™ is then loaded into rail cars and shipped to various customers around the world, where they process it into their own products.

Sorona® Manufacturing

One of the most exciting consumer-oriented applications is DuPont™ Sorona®, a renewably sourced polymer used to create bio-based fibers for carpet and apparel.

The Sorona® polymer manufacturing process takes place at the DuPont™ Sorona® facility in Kinston, NC as well as facilities in China.

Bio-PDO™ is offloaded from railcars into tanks, and then goes through a continuous polymerization operation. After the Sorona® polymer is produced, it is extruded into multiple strands. Once cooled, these strands then go through a pelletizer, which chops them into small, candy-sized pieces.

These pellets then go into a classifier that removes unwanted particles and long strands. The pellets fall into a sack, which is then weighed. The final product is shipped to customers around the world.

The Environmental Effect

With Bio-PDO™, DuPont has found another way to reduce dependence on fossil fuels. The production of Bio-PDO™ consumes up to 40% less energy and reduces greenhouse gas emissions by more than 40% versus petroleum-based PDO.

Using Bio-PDO™ as a key ingredient, the production of Sorona® reduces greenhouse gas emissions by 63% over petroleum-based nylon 6.

Sorona® Use in Carpet and Apparel

Lauded as one of the most exciting innovations in residential carpeting in 20 years, Mohawk SmartStrand® with DuPont™ Sorona® offers engineered-in, permanent stain protection, exceptional softness and outstanding durability.

Apparel manufacturers appreciate that Sorona® combines the best of both nylon and polyester in one fiber, delivering extraordinary softness, exceptional comfort stretch, brilliant color and easy care. All of these attributes enhance the look, feel and quality of active wear, swimwear, intimates, denim and other apparel.

Bio-PDO™ and Sorona®: A Winning Combination

Sorona® is a high-performance polymer that, thanks to Bio-PDO™, has the added benefit of being based on renewable resources. Using bio-based fibers like Sorona®, carpet and apparel manufacturers can make better products and help minimize their impact on the environment.

Sorona® contains 37% annually renewable plant based ingredients by weight (28% biobased carbon)