Optimization of a hybrid bacterial/Arabidopsis thaliana fatty acid synthase system II in Saccharomyces cerevisiae

• Published in: Metabolic engineering communications Vol. 17; p. e00224
• Main Authors: Pozdniakova, Tatiana A., Cruz, João P., Silva, Paulo César, Azevedo, Flávio, Parpot, Pier, Domingues, Maria Rosario, Carlquist, Magnus, Johansson, Björn
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-12-2023; Elsevier
• Subjects: Biochemistry and Molecular Biology; Biokemi och molekylärbiologi; Biologi; Biological Sciences; E. coli; FASI; FASII; Fatty acid synthase; Full Length; Metabolic engineering; Microbiology; Mikrobiologi; Natural Sciences; Naturvetenskap; Saccharomyces cerevisiae; FASI; FASII; Metabolic engineering; Fatty acid synthase; Saccharomyces cerevisiae; E. coli
• ISSN: 2214-0301; 2214-0301
• DOI: 10.1016/j.mec.2023.e00224

Fatty acids are produced by eukaryotes like baker's yeast Saccharomyces cerevisiae mainly using a large multifunctional type I fatty acid synthase (FASI) where seven catalytic steps and a carrier domain are shared between one or two protein subunits. While this system may offer efficiency in catalysis, only a narrow range of fatty acids are produced. Prokaryotes, chloroplasts and mitochondria rely instead on a FAS type II (FASII) where each catalytic step is carried out by a monofunctional enzyme encoded by a separate gene. FASII is more flexible and capable of producing a wider range of fatty acid structures, such as the direct production of unsaturated fatty acids. An efficient FASII in the preferred industrial organism S. cerevisiae could provide a platform for developing sustainable production of specialized fatty acids. We functionally replaced either yeast FASI genes (FAS1 or FAS2) with a FASII consisting of nine genes from Escherichia coli (acpP, acpS and fab -A, -B, -D, -F, -G, -H, -Z) as well as three from Arabidopsis thaliana (MOD1, FATA1 and FATB). The genes were expressed from an autonomously replicating multicopy vector assembled using the Yeast Pathway Kit for in-vivo assembly in yeast. Two rounds of adaptation led to a strain with a maximum growth rate (μmax) of 0.19 h−1 without exogenous fatty acids, twice the growth rate previously reported for a comparable strain. Additional copies of the MOD1 or fabH genes resulted in cultures with higher final cell densities and three times higher lipid content compared to the control.
•Thirteen fatty acid genes expressed simultaneously on a multicopy vector.•Yeast fatty acid synthase replaced with genes from E. coli and Arabidopsis thaliana.•Maximum growth rate (μmax) of 0.19 h–1.•Additional gene copies of MOD1 (Enoyl-ACP reductase) or fabH improve growth.•Three times more lipid accumulation than wild type.