Kobalter Simon, Voit Alena, Bekerle-Bogner Myria, Rudalija Haris, Haas Anne, Wriessnegger Tamara, Pichler Harald
Austrian Centre of Industrial Biotechnology (acib GmbH), Petersgasse 14, 8010 Graz, Austria.
Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, BioTechMed Graz, Petersgasse 14, 8010 Graz, Austria.
Bioengineering (Basel). 2023 Dec 12;10(12):1412. doi: 10.3390/bioengineering10121412.
Fatty acids have been supplied for diverse non-food, industrial applications from plant oils and animal fats for many decades. Due to the massively increasing world population demanding a nutritious diet and the thrive to provide feedstocks for industrial production lines in a sustainable way, i.e., independent from food supply chains, alternative fatty acid sources have massively gained in importance. Carbohydrate-rich side-streams of agricultural production, e.g., molasses, lignocellulosic waste, glycerol from biodiesel production, and even CO, are considered and employed as carbon sources for the fermentative accumulation of fatty acids in selected microbial hosts. While certain fatty acid species are readily accumulated in native microbial metabolic routes, other fatty acid species are scarce, and host strains need to be metabolically engineered for their high-level production. We report the metabolic engineering of to produce palmitoleic acid from glucose and discuss the beneficial and detrimental engineering steps in detail. Fatty acid secretion was achieved through the deletion of fatty acyl-CoA synthetases and overexpression of the truncated thioesterase '. The best strains secreted >1 g/L free fatty acids into the culture medium. Additionally, the introduction of C16-specific ∆9-desaturases and fatty acid synthases, coupled with improved cultivation conditions, increased the palmitoleic acid content from 5.5% to 22%.
几十年来，脂肪酸一直从植物油和动物脂肪中提取，用于各种非食品工业应用。由于世界人口大量增加，需要营养丰富的饮食，并且人们致力于以可持续的方式，即独立于食品供应链，为工业生产线提供原料，替代脂肪酸来源的重要性大幅提高。农业生产中富含碳水化合物的副产品，如糖蜜、木质纤维素废料、生物柴油生产中的甘油，甚至一氧化碳，都被视为并用作选定微生物宿主中脂肪酸发酵积累的碳源。虽然某些脂肪酸种类很容易在天然微生物代谢途径中积累，但其他脂肪酸种类却很稀少，需要对宿主菌株进行代谢工程改造以实现其高水平生产。我们报告了利用葡萄糖生产棕榈油酸的代谢工程改造，并详细讨论了有益和有害的工程步骤。通过删除脂肪酰辅酶A合成酶和过表达截短的硫酯酶，实现了脂肪酸的分泌。最佳菌株向培养基中分泌了超过1 g/L的游离脂肪酸。此外，引入C16特异性Δ9-去饱和酶和脂肪酸合酶，再加上改进的培养条件，使棕榈油酸含量从5.5%提高到了22%。
