title: Awakening the endogenous Leloir pathway for efficient galactose utilization by Yarrowia lipolytica.
abstract: BACKGROUND
  Production of valuable metabolites by Yarrowia lipolytica using renewable raw materials is of major interest for sustainable food and energy. Galactose is a monosaccharide found in galactomannans, hemicelluloses, gums, and pectins.
  
  
  RESULTS
  Yarrowia lipolytica was found to express all the Leloir pathway genes for galactose utilization, which encode fully functional proteins. Gene organization and regulation in Y. lipolytica resembles filamentous fungi rather than Saccharomyces cerevisiae. After Y. lipolytica was grown on mixture of glucose and galactose, it was then able to metabolize galactose, including when glucose concentrations were higher than 4 g/L. However, glucose was still the preferred carbon source. Nonetheless, a strain overexpressing the four ylGAL genes of the Leloir pathway was able to efficiently use galactose as its sole carbon source. This mutant was used to produce citric acid and lipids from galactose; the yields were comparable to or greater than that obtained for the parental strain (W29) on glucose.
  
  
  CONCLUSIONS
  The construction of a Y. lipolytica strain able to produce citric acid and lipids from galactose is a very important step in bypassing issues related to the use of food-based substrates in industrial applications.
authors.affiliation: INRA, UMR1319 Micalis, 78352 Jouy-en-Josas, France ; AgroParisTech, UMR Micalis, 78352 Jouy-en-Josas, France ; Department of Biotechnology and Food Microbiology, Wroclaw University of Environmental and Life Sciences, Chełmońskiego 37/41, 51-630 Wroclaw, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Lazar
authors.affiliation: INRA, UMR1319 Micalis, 78352 Jouy-en-Josas, France ; AgroParisTech, UMR Micalis, 78352 Jouy-en-Josas, France.
authors.forename: Heber
authors.initials: H
authors.lastname: Gamboa-Meléndez
authors.affiliation: INRA, UMR1319 Micalis, 78352 Jouy-en-Josas, France ; AgroParisTech, UMR Micalis, 78352 Jouy-en-Josas, France.
authors.forename: Anne-Marie Crutz-
authors.initials: AM
authors.lastname: Le Coq
authors.affiliation: INRA, UMR1319 Micalis, 78352 Jouy-en-Josas, France ; AgroParisTech, UMR Micalis, 78352 Jouy-en-Josas, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Neuvéglise
authors.affiliation: INRA, UMR1319 Micalis, 78352 Jouy-en-Josas, France ; AgroParisTech, UMR Micalis, 78352 Jouy-en-Josas, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Nicaud
keywords: Citric acid; GAL genes; Galactose; Lipid accumulation; Metabolic pathways; Single-cell oil; Yeasts