Presidential Green Chemistry Challenge: 2003 Greener Reaction Conditions Award
Microbial Production of 1,3-Propanediol
Innovation and Benefits: DuPont and Genencor International jointly developed a genetically engineered microorganism to manufacture the key building block for DuPont's Sorona® polyester. The process uses renewable cornstarch instead of petroleum to make environmentally friendly, cost-competitive textiles.
Summary of Technology: DuPont is integrating biology in the manufacture of its newest polymer platform, DuPont Sorona® polymer. Combining metabolic engineering with polymer science, researchers are introducing a microbial process in a business that, historically, has relied solely on traditional chemistry and petrochemical feedstocks. This achievement, comprising biocatalytic production of 1,3-propanediol from renewable resources, offers economic as well as environmental advantages. The key to the novel biological process is an engineered microorganism that incorporates several enzyme reactions, obtained from naturally occurring bacteria and yeast, into an industrial host cell line. For the first time, a highly engineered microorganism will be used to convert a renewable resource into a chemical at high volume.
The catalytic efficiency of the engineered microorganism allows replacement of a petroleum feedstock, reducing the amount of energy needed in manufacturing steps and improving process safety. The microbial process is environmentally green, less expensive, and more productive than the chemical operations it replaces. 1,3-Propanediol, a key ingredient in the Sorona® polymers, provides advantageous attributes for apparel, upholstery, resins, and nonwoven applications.
Scientists and engineers from DuPont and Genencor International, Inc. redesigned a living microbe to produce 1,3-propanediol. Inserting biosynthetic pathways from several microorganisms into an industrial host cell line allows the direct conversion of glucose to 1,3-propanediol, a route not previously available in a single microorganism. Genes from a yeast strain with the ability to convert glucose, derived from cornstarch, to glycerol were inserted into the host. Genes from a bacterium with the ability to transform glycerol to 1,3-propanediol were also incorporated. Additionally, the reactions present naturally in the host were altered to optimize product formation. The modifications maximize the ability of the organism to convert glucose to 1,3-propanediol while minimizing its ability to produce biomass and unwanted byproducts. Coalescing enzyme reactions from multiple organisms expands the range of materials that can be economically produced by biological means.
For more than 50 years, scientists have recognized the performance benefits of polyesters produced with 1,3-propanediol; however, the high cost of manufacturing the ingredient using petroleum feedstock and traditional chemistry kept it from the marketplace. The biological process using glucose as starting material will enable cost-effective manufacture of Sorona® polymer, which will offer consumer fabrics with softness, stretch and recovery, easy care, stain resistance, and colorfastness. A unique kink in the structure of the polymer containing 1,3-propanediol allows recovery at a high rate when it is stretched. As a result, Sorona® improves fit and comfort because the fabric quickly recovers its original shape when stretched, for example, in knees or elbows. The resilience of Sorona® also adds beneficial features to automotive upholstery and home textiles. In resin applications, Sorona®'s barrier characteristics protect moisture, taste, and odor.
Biology offers chemical manufacturers attractive options for the production of chemicals while adhering to the principles of green chemistry. This microbial production of a key polymer ingredient from renewable sources is one example. By integrating biology with chemistry, physics, and engineering, DuPont develops new solutions that enhance the environment and improve upon existing materials.
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