Lori Maggio-Hall, senior research microbiologist at DuPont Central Research and Development delivered the talk, “Metabolic Engineering of E. coli for the Commercial Production of 1,3-propanediol,” at the Virginia Bioinformatics Institute (VBI) on Tuesday, June 15. Maggio-Hall was a special guest lecturer for the Research Experiences for Undergraduates (REU) Site: Microbiology in the Post Genome Era, which is led by VBI Associate Professor Biswarup Mukhopadhyay.

Maggio-Hall discussed DuPont’s successful development and commercial-scale implementation of a bioprocess to convert corn sugar to 1,3-propanediol (BioPDO). This project serves as a perfect example of team science in action, involving approximately 50 scientists with expertise in microbiology, biochemistry, mathematics, and engineering. DuPont’s goal was to develop a new type of polyester with vastly superior properties.  The polyester, commercialized under the name Sorona®, is now widely available in Mohawk® carpeting.  The BioPDO monomer is also used in a number of commercial products, from biodegradable airplane deicers to shampoo.  DuPont won a 2003 Presidential Green Chemistry Challenge Award for their development of the fermentation process for production of 1,3-propanediol from corn-derived glucose in recombinant Escherichia coli K-12. According to Maggio-Hall, DuPont began production of the polymer in 2006.

Maggio-Hall’s key take away messages were: 

•    Economic analysis dictates selection of biological targets and critical pathways

•    Reaching the production phase was a long process because a low-cost chemical production method could not be identified, which led to the decision to use a bioprocess

•    Focus during the development process was on rate (speed of the chemical reaction), titer (measure of concentration), and yield (the amount of product obtained)

Researchers working on this project introduced genes encoding a BioPDO pathway into E. coli to construct the biocatalyst.  Multiple metabolic engineering approaches were used to optimize the BioPDO pathway and to modify the host’s native metabolism to maximize carbon flux from glucose into the product pathway. Maggio-Hall explained how both yield and titer played very important roles in developing 1,3-propanediol in an economically feasible way.

According to Maggio-Hall, “What we wanted to do was make less of everything else that was produced during the process and more of our product.”

Maggio-Hall met with REU and graduate students, as well as faculty members, and shared her experiences from her journey as an undergraduate at the University of Illinois at Urbana-Champaign, to her Ph.D. and postdoctoral work at the University of Wisconsin, to her current position at DuPont. REU Site: Microbiology in the Post Genome Era is supported by the National Science Foundation (NSF), Virginia Tech’s Fralin Life Science Institute, and VBI.

Published by Barry Whyte, June 17, 2010