Title

Dynamic Regulation Of Biodiesel Producing Escrechia Coli Biosynthetic Pathways

Author(s)

Thomas Stanton

School Name

South Carolina Governor's School for Science and Mathematics

Grade Level

12th Grade

Presentation Topic

Biochemistry

Presentation Type

Mentored

Mentor

Mentor: Mark Blenner, Department of Chemical Engineering, Clemson University

Abstract

FAEE (Fatty Acid Ethyl Ester) is a biodiesel valued as an alternative to the depleting fossil fuel supply. This is due to its high energy density, low water solubility, and low toxicity to production hosts like E. coli. The engineered W strain of E. coli has been developed to contain biosynthetic pathways that produce FAEE from fermentable sugars. The W strain contains a dynamically regulated FAEE pathway with three distinct modules. Accumulation of the key intermediate ethanol in E. coli inhibits cell growth, and thus, FAEE production. Since ethanol in module B is produced at a much faster rate than fatty acyl-CoA (in module A), FAEE yields (in module C) can be improved by controlling ethanol production to match fatty acyl-CoA production. Due to the dynamic pathways of the W strain, induction by L-arabinose, a 5-carbon sugar, increases FAEE production. To test the sensitivity of L-arabinose induction in increasing FAEE production, we added various concentrations of up to 0.2% L-arabinose to W cell cultures and then used gas chromatography to analyze the products. We discovered that, at the tested concentrations, L-arabinose induction is not effective in maximizing FAEE yield. Future projects include manipulation of specific genes in module B. Less efficient enzymes in that pathway would slow ethanol production and increase FAEE production.

Start Date

4-11-2015 11:00 AM

End Date

4-11-2015 11:15 AM

COinS
 
Apr 11th, 11:00 AM Apr 11th, 11:15 AM

Dynamic Regulation Of Biodiesel Producing Escrechia Coli Biosynthetic Pathways

FAEE (Fatty Acid Ethyl Ester) is a biodiesel valued as an alternative to the depleting fossil fuel supply. This is due to its high energy density, low water solubility, and low toxicity to production hosts like E. coli. The engineered W strain of E. coli has been developed to contain biosynthetic pathways that produce FAEE from fermentable sugars. The W strain contains a dynamically regulated FAEE pathway with three distinct modules. Accumulation of the key intermediate ethanol in E. coli inhibits cell growth, and thus, FAEE production. Since ethanol in module B is produced at a much faster rate than fatty acyl-CoA (in module A), FAEE yields (in module C) can be improved by controlling ethanol production to match fatty acyl-CoA production. Due to the dynamic pathways of the W strain, induction by L-arabinose, a 5-carbon sugar, increases FAEE production. To test the sensitivity of L-arabinose induction in increasing FAEE production, we added various concentrations of up to 0.2% L-arabinose to W cell cultures and then used gas chromatography to analyze the products. We discovered that, at the tested concentrations, L-arabinose induction is not effective in maximizing FAEE yield. Future projects include manipulation of specific genes in module B. Less efficient enzymes in that pathway would slow ethanol production and increase FAEE production.