278981 An Integrated Computational and Experimental Study for the Overproduction of Fatty Acids in Escherichia Coli
Sridhar Ranganathan 1, Anupam Chowdhury2, Ali R. Zomorrodi2, Ting Wei Tee 3, Jong Moon Yoon 3+, Yanfen Fu 3, Jacqueline V. Shanks 3, and Costas D. Maranas2
1 Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA
2 Department of Chemical Engineering, Pennsylvania State University, University Park, PA
3 Department of Chemical and Biological Engineering, Iowa State University, Ames, IA
Fatty acids of varying chain lengths (C6 – C16) naturally synthesized in many organisms are promising starting points for the catalytic production of industrial chemicals and diesel-like biofuels. However, bio-production of fatty acids from plants and other microbial production hosts relies heavily on manipulating tightly regulated fatty acid biosynthetic pathways. In addition, precursors for fatty acids are used along other central metabolic pathways for the production of amino acids and biomass, which further complicates the engineering of microbial hosts for higher yields. In this study, we demonstrate an iterative metabolic engineering effort that integrates computationally driven predictions and metabolic flux analysis techniques to meet this challenge. The OptForce procedure, our recently developed computational strain design algorithm, was used for suggesting and prioritizing genetic manipulations that overproduce fatty acids of different chain lengths from C6 to C16 starting with wild-type E. coli. We identified some chain-specific genetic interventions alluding to the possibility of fine-tuning overproduction for specific fatty acid chain lengths. In accordance with the OptForce prioritization of interventions, fabZ and acyl-ACP thioesterase were upregulated and fadD was deleted to arrive at a strain that produces 1.70 g/L and 0.14 g fatty acid/g glucose (~ 39% maximum theoretical yield) of C14-16 fatty acid in minimal M9 medium. OptForce suggested additional modifications distal from the fatty acid synthesis pathways that led to additional improvements in yield. Our study reinforces the advantage of integrating computational and experimental tools for the design and engineering of microbial strains to overproduce value-added chemicals or biofuels.
See more of this Group/Topical: Food, Pharmaceutical & Bioengineering Division - See also TI: Comprehensive Quality by Design in Pharmaceutical Development and Manufacture