Terminally hydroxylated fatty acids or dicarboxylic acids are industrially relevant compounds with broad applications. Here, we present the proof of principle for the de novo biosynthesis of 8-hydroxyoctanoic acid from glucose and ethanol in the yeast Saccharomyces cerevisiae. Toxicity tests with medium-chain length ω-hydroxy fatty acids and dicarboxylic acids revealed little or no growth impairments on yeast cultures even at higher concentrations. The ability of various heterologous cytochrome P450 enzymes in combination with their cognate reductases for ω-hydroxylation of externally fed octanoic acid were compared. Finally, the most efficient P450 enzyme system was expressed in a yeast strain, whose fatty acid synthase was engineered for octanoic acid production, resulting in de novo biosynthesis of 8-hydroxyoctanoic acid up to 3 mg/l. Accumulation of octanoic acid revealed that cytochromes P450 activities were limiting 8-hydroxyoctanoic acid synthesis. The hydroxylation of both externally added and intracellularly produced octanoic acid was strongly dependent on the carbon source used, with ethanol being preferred. We further identified the availability of heme, a cofactor needed for P450 activity, as a limiting factor of 8-hydroxyoctanoic acid biosynthesis.

中文翻译：

---

通过中链长度特异性脂肪酸合酶和细胞色素P450在酿酒酵母中从头生物合成8-羟基辛酸

末端羟基化的脂肪酸或二羧酸是在工业上具有广泛应用的相关化合物。在这里，我们提供了从酿酒酵母中的葡萄糖和乙醇中从头生物合成8-羟基辛酸的原理性证明。用中等链长的ω-羟基脂肪酸和二羧酸进行的毒性试验表明，即使在较高浓度下，酵母培养物的生长损害也很少或没有。比较了各种异源细胞色素P450酶及其同源还原酶对外部进料辛酸ω-羟基化的能力。最后，最有效的P450酶系统在酵母菌株中表达，该菌株的脂肪酸合酶经过工程改造以生产辛酸，从而从头开始生物合成8羟基辛酸，最高可达3 mg / l。辛酸的积累表明，细胞色素P450的活性限制了8-羟基辛酸的合成。外部添加的和细胞内产生的辛酸的羟基化强烈依赖于所使用的碳源，优选乙醇。我们进一步确定了血红素的可用性，血红素是P450活性所需的辅助因子，是8-羟基辛酸生物合成的限制因子。