Institute for Synthetic Biosystem, Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Institute for Synthetic Biosystem, Department of Biochemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
Bioresour Technol. 2018 Jun;257:339-343. doi: 10.1016/j.biortech.2018.02.096. Epub 2018 Feb 23.
Oleanolic acid is a plant-derived pentacyclic triterpenoid compound with various biological activities. Recently, biosynthesis of oleanolic acid in microbes has been demonstrated as a promising and green way, but the production is too low for industrialization. To improve oleanolic acid production, this study constructed a novel pathway for biosynthesis of oleanolic acid in Saccharomyces cerevisiae by improving the pairing efficiency between cytochrome P450 monooxygenase and reductase. Furthermore, to improve the transcriptional efficiency of heterologous genes, the cellular galactose regulatory network was reconstructed by knocking out galactose metabolic genes GAL80 and GAL1. Finally, the 3-hydroxy-3-methylglutaryl-CoA reductase, squalene synthase and 2,3-oxidosqualene synthase were further overexpressed, increasing oleanolic acid production up to 186.1 ± 12.4 mg/L in flask shake. Combined with fermentation optimization, the final oleanolic acid production was 606.9 ± 9.1 mg/L with a yield of 16.0 ± 0.8 mg/g DCW which was 7.6-fold higher than the reported maximum production.
齐墩果酸是一种植物来源的五环三萜化合物，具有多种生物活性。最近，微生物中齐墩果酸的生物合成被证明是一种有前途的绿色方法，但产量太低，无法实现工业化。为了提高齐墩果酸的产量，本研究通过提高细胞色素 P450 单加氧酶和还原酶之间的配对效率，在酿酒酵母中构建了一条新型的齐墩果酸生物合成途径。此外，为了提高异源基因的转录效率，通过敲除半乳糖代谢基因 GAL80 和 GAL1 来重建细胞内半乳糖调控网络。最后，进一步过表达 3-羟-3-甲基戊二酰辅酶 A 还原酶、鲨烯合酶和 2,3-氧化鲨烯合酶，使齐墩果酸的产量在摇瓶中提高到 186.1±12.4mg/L。结合发酵优化，最终齐墩果酸的产量为 606.9±9.1mg/L，得率为 16.0±0.8mg/g DCW，比报道的最高产量提高了 7.6 倍。
