title: Functional genomics analysis of free fatty acid production under continuous phosphate limiting conditions.
abstract: Free fatty acids (FFA) are an attractive platform chemical that serves as a functional intermediate in metabolic pathways for producing oleochemicals. Many groups have established strains of Escherichia coli capable of producing various chain-length mixtures of FFA by heterologous expression of acyl-ACP thioesterases. For example, high levels of dodecanoic acid are produced by an E. coli strain expressing the Umbellularia californica FatB2 thioesterase, BTE. Prior studies achieved high dodecanoic acid yields and productivities under phosphate-limiting media conditions. In an effort to understand the metabolic and physiological changes that led to increased FFA production, the transcriptome of this strain was assessed as a function of nutrient limitation and growth rate. FFA generation under phosphate limitation led to consistent changes in transporter expression, osmoregulation, and central metabolism. Guided by these results, targeted knockouts led to a further ~11 % in yield in FFA.
authors.affiliation: Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI, USA.
authors.forename: J Tyler
authors.initials: JT
authors.lastname: Youngquist
authors.affiliation: Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI, USA.|Graduate Program in Environmental Chemistry and Technology, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: Travis C
authors.initials: TC
authors.lastname: Korosh
authors.affiliation: Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI, USA. pfleger@engr.wisc.edu.|Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA. pfleger@engr.wisc.edu.
authors.forename: Brian F
authors.identifier: 0000-0002-9232-9959
authors.initials: BF
authors.lastname: Pfleger
mesh_terms: D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D005230:Fatty Acids, Nonesterified / Q000096:biosynthesis* / Q000378:metabolism; D023281:Genomics; D007850:Lauric Acids / Q000378:metabolism; D053858:Metabolic Networks and Pathways / Q000187:drug effects; D010710:Phosphates / Q000378:metabolism* / Q000494:pharmacology; D013869:Thiolester Hydrolases / Q000235:genetics / Q000378:metabolism
chemical_list: D005230:Fatty Acids, Nonesterified; D007850:Lauric Acids; D010710:Phosphates; C030358:lauric acid; D013869:Thiolester Hydrolases; C018748:oleoyl-(acyl-carrier-protein) hydrolase
keywords: Escherichia coli; Free fatty acid; Functional genomics; Microarray; Phosphate limitation; Thioesterase