title: Orthogonal Fatty Acid Biosynthetic Pathway Improves Fatty Acid Ethyl Ester Production in Saccharomyces cerevisiae.
abstract: Fatty acid ethyl esters (FAEEs) are a form of biodiesel that can be microbially produced via a transesterification reaction of fatty acids with ethanol. The titer of microbially produced FAEEs can be greatly reduced by unbalanced metabolism and an insufficient supply of fatty acids, resulting in a commercially inviable process. Here, we report on a pathway engineering strategy in Saccharomyces cerevisiae for enhancing the titer of microbially produced FAEEs by providing the cells with an orthogonal route for fatty acid synthesis. The fatty acids generated from this heterologous pathway would supply the FAEE production, safeguarding endogenous fatty acids for cellular metabolism and growth. We investigated the heterologous expression of a Type-I fatty acid synthase (FAS) from Brevibacterium ammoniagenes coupled with WS/DGAT, the wax ester synthase/acyl-coenzyme that catalyzes the transesterification reaction with ethanol. Strains harboring the orthologous fatty acid synthesis yielded a 6.3-fold increase in FAEE titer compared to strains without the heterologous FAS. Variations in fatty acid chain length and degree of saturation can affect the quality of the biodiesel; therefore, we also investigated the diversity of the fatty acid production profile of FAS enzymes from other Actinomyces organisms.
authors.affiliation: †Department of Chemical and Biomolecular Engineering, ‡Institute for Genomic Biology and the Energy Biosciences Institute, and §Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Dawn T
authors.initials: DT
authors.lastname: Eriksen
authors.affiliation: †Department of Chemical and Biomolecular Engineering, ‡Institute for Genomic Biology and the Energy Biosciences Institute, and §Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Mohammad
authors.initials: M
authors.lastname: HamediRad
authors.affiliation: †Department of Chemical and Biomolecular Engineering, ‡Institute for Genomic Biology and the Energy Biosciences Institute, and §Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: †Department of Chemical and Biomolecular Engineering, ‡Institute for Genomic Biology and the Energy Biosciences Institute, and §Departments of Chemistry, Biochemistry, and Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhao
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001951:Brevibacterium / Q000201:enzymology; D003001:Cloning, Molecular; D054890:Fatty Acid Synthase, Type I / Q000235:genetics / Q000378:metabolism; D005227:Fatty Acids / Q000096:biosynthesis*; D060847:Metabolic Engineering; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D005227:Fatty Acids; D054890:Fatty Acid Synthase, Type I
keywords: advanced biofuels; biodiesel; fatty acid ethyl esters (FAEEs); fatty acid synthase; orthogonal fatty acid synthesis; pathway and metabolic engineering