title: Physiological and transcriptional characterization of Saccharomyces cerevisiae engineered for production of fatty acid ethyl esters.
abstract: Saccharomyces cerevisiae has previously been engineered to become a cell factory for the production of fatty acid ethyl esters (FAEEs), molecules suitable for crude diesel replacement. To find new metabolic engineering targets for the improvement of FAEE cell factories, three different FAEE-producing strains of S. cerevisiae, constructed previously, were compared and characterized by quantification of key fluxes and genome-wide transcription analysis. From both the physiological and the transcriptional data, it was indicated that strain CB2I20, with high expression of a heterologous wax ester synthase gene (ws2) and strain BdJ15, containing disruptions of genes DGA1, LRO1, ARE1, ARE2 and POX1, which prevent the conversion of acyl-CoA to sterol esters, triacylglycerides and the degradation to acetyl-CoA, triggered oxidative stress that consequently influenced cellular growth. In the latter strain, stress was possibly triggered by disabling the buffering capacity of lipid droplets in encapsulating toxic fatty acids such as oleic acid. Additionally, it was indicated that there was an increased demand for NADPH required for the reduction steps in fatty acid biosynthesis. In conclusion, our analysis clearly shows that engineering of fatty acid biosynthesis results in transcriptional reprogramming and has a significant effect on overall cellular metabolism.
authors.affiliation: Department of Biology and Biological Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden.
authors.forename: Bouke Wim
authors.initials: BW
authors.lastname: de Jong
authors.affiliation: Department of Biology and Biological Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, SE-41296 Gothenburg, Sweden.
authors.forename: Verena
authors.initials: V
authors.lastname: Siewers
authors.affiliation: Department of Biology and Biological Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden Novo Nordisk Foundation Center for Biosustainability, Chalmers University of Technology, SE-41296 Gothenburg, Sweden Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, DK-2970 Hørsholm, Denmark nielsenj@chalmers.se.
authors.forename: Jens
authors.initials: J
authors.lastname: Nielsen
mesh_terms: D000217:Acyltransferases / Q000378:metabolism; D056804:Biofuels; D004952:Esters / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism*; D020869:Gene Expression Profiling; D060847:Metabolic Engineering; D064688:Metabolic Flux Analysis; D009249:NADP / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*
chemical_list: D056804:Biofuels; D004952:Esters; D005227:Fatty Acids; D009249:NADP; D000217:Acyltransferases; C074049:fatty acid modifying enzyme
keywords: batch fermentation; fatty acid ethyl ester; microarray; yeast