该文以酿酒酵母BY4741作为底盘细胞,通过系统代谢工程改造提高游离脂肪酸(free fatty acid,FFAs)的合成。首先,通过删除酰基CoA合成酶FAA1、FAA4以及 FAT1的编码基因,提高FFAs的合成,酵母工程菌株 FFAs达到384.4 mg/L。进一步,通过敲除POX1、FAA2和PXA2基因,破坏了酵母细胞的β-氧化途径,使细胞外FFAs进一步提高,达到了394.9 mg/L。随后,通过敲除磷脂酸磷酸酶编码基因DPP1,LPP1,PAH1,降低了磷脂酸(phosphatidic acid,PA)的去磷酸化水平,上调了获得的多基因缺失的酵母工程菌(Δfaa1 Δfaa4 Δfat1 Δpox1 Δfaa2 Δpxa2 Δdpp1 Δlpp1 Δpah1)能够产生497.3 mg/L的细胞外游离脂肪酸,以及1 332.2 mg/L的总脂肪酸。通过组合代谢工程产生的平台菌株,为未来发展脂质相关的细胞工厂提供了基础。
Fatty acids are attractive biomolecules that have important applications in industry because of their high energy content and their use as precursors for other high-value chemicals. Bio-based production of fatty acids can enable sustainable substitution of petroleum-derived fuels and chemicals. In this paper, we used Saccharomyces cerevisiae BY4741 as a chassis cell to enhance the synthesis of free fatty acids (FFAs) through systematic metabolic engineering modifications. First, the synthesis of FFAs was enhanced by deleting the genes encoding acyl-CoA synthases FAA1, FAA4, and FAT1, and the FFAs of the yeast engineered strain reached 384.4 mg/L. Further, the β-oxidation pathway of the yeast cells was disrupted by knocking out POX1, FAA2, and PXA2, which further enhanced the extracellular FFAs to 394.9 mg/L. Subsequently, dephosphorylation of phosphatidic acid (PA) was reduced by knocking out the genes encoding phosphatidic acid phosphatases DPP1, LPP1, and PAH1, upregulating the ability of the obtained yeast engineered with multiple gene deletions (Δfaa1 Δfaa4 Δfat1 Δpox1 Δfaa2 Δpxa2 Δdpp1 Δlpp1 Δpah1) to produce 497.3 mg/L of extracellular free fatty acids, and 1332.2 mg/L of total fatty acids. The platform strains generated by combinatorial metabolic engineering provide a basis for the future development of lipid-related cell factories.
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