title: Metabolic engineering of Yarrowia lipolytica for itaconic acid production.
abstract: Itaconic acid is a naturally produced organic acid with diverse applications as a replacement for petroleum derived products. However, its industrial viability as a bio-replacement has been restricted due to limitations with native producers. In this light, Yarrowia lipolytica is an excellent potential candidate for itaconic acid production due to its innate capacity to accumulate citric acid cycle intermediates and tolerance to lower pH. Here, we demonstrate the capacity to produce itaconic acid in Y. lipolytica through heterologous expression of the itaconic acid synthesis enzyme, resulting in an initial titer of 33 mg/L. Further optimizations of this strain via metabolic pathway engineering, enzyme localization, and media optimization strategies enabled 4.6g/L of itaconic acid to be produced in bioreactors, representing a 140-fold improvement over initial titer. Moreover, these fermentation conditions did not require additional nutrient supplementation and utilized a low pH condition that enabled the acid form of itaconic acid to be produced. Overall yields (0.058 g/g yield from glucose) and maximum productivity of 0.045 g/L/h still provide areas for future strain improvement. Nevertheless, this work demonstrates that Y. lipolytica has the potential to serve as an industrially relevant platform for itaconic acid production.
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, United States.
authors.forename: John
authors.initials: J
authors.lastname: Blazeck
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, United States.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hill
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, United States.
authors.forename: Mariam
authors.initials: M
authors.lastname: Jamoussi
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, United States.
authors.forename: Anny
authors.initials: A
authors.lastname: Pan
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, United States.
authors.forename: Jarrett
authors.initials: J
authors.lastname: Miller
authors.affiliation: McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, United States; Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, TX 78712, United States. Electronic address: halper@che.utexas.edu.
authors.forename: Hal S
authors.initials: HS
authors.lastname: Alper
mesh_terms: D019149:Bioreactors; D002952:Citric Acid Cycle; D003001:Cloning, Molecular; D003470:Culture Media; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D060847:Metabolic Engineering / Q000379:methods*; D010957:Plasmids; D013386:Succinates / Q000378:metabolism*; D025062:Yarrowia / Q000235:genetics* / Q000378:metabolism*
chemical_list: D003470:Culture Media; D013386:Succinates; D005947:Glucose; C005229:itaconic acid
keywords: Citric acid; Itaconic acid; Metabolic engineering; Yarrowia lipolytica