title: Overproduction of fatty acids in engineered Saccharomyces cerevisiae.
abstract: The long hydrocarbon fatty acyl chain is energy rich, making it an ideal precursor for liquid transportation fuels and high-value oleo chemicals. As Saccharomyces cerevisiae has many advantages for industrial production compared to Escherichia coli. Here, we attempted to engineer Saccharomyces cerevisiae for overproduction of fatty acids. First, disruption of the beta-oxidation pathway, elimination of the acyl-CoA synthetases, overexpression of different thioesterases and acetyl-CoA carboxylase ACC1, and engineering the supply of precursor acetyl-CoA. The engineered strain XL122 produced more than 120 mg/L of fatty acids. In parallel, we inactivated ADH1, the dominant gene for ethanol production, to redirect the metabolic flux to fatty acids synthesis. The engineered strain DG005 produced about 140 mg/L fatty acids. Additionally, Acetyl-CoA carboxylase was identified as a critical bottleneck of fatty acids synthesis in S. cerevisiae with a cell-free system. However, overexpression of ACC1 has little effect on fatty acids biosynthesis. As it has been reported that phosphorylation of ACC1 may influent its activity, so phosphorylation sites of ACC1 were further identified. Although the regulatory mechanisms remain unclear, our results provide rationale for future studies to target this critical step. All these efforts, particularly the discovery of the limiting step are critical for developing a "cell factory" for the overproduction of fatty acids by using type I fatty acids synthase in yeast or other fungi.
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Li
authors.forename: Daoyi
authors.initials: D
authors.lastname: Guo
authors.forename: Yongbo
authors.initials: Y
authors.lastname: Cheng
authors.forename: Fayin
authors.initials: F
authors.lastname: Zhu
authors.forename: Zixin
authors.initials: Z
authors.lastname: Deng
authors.forename: Tiangang
authors.initials: T
authors.lastname: Liu
mesh_terms: D056804:Biofuels; D005227:Fatty Acids / Q000378:metabolism*; D017353:Gene Deletion; D015870:Gene Expression; D060847:Metabolic Engineering; D064688:Metabolic Flux Analysis; D053858:Metabolic Networks and Pathways / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*
chemical_list: D056804:Biofuels; D005227:Fatty Acids
keywords: Saccharomyces cerevisiae; acetyl-CoA carboxylase; cell-free; fatty acids biosynthesis; fatty acids derived biofuel; phosphorylation