State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, P. R. China.
Microb Cell Fact. 2024 Oct 24;23(1):291. doi: 10.1186/s12934-024-02565-0.
Succinic acid (SA) is an important bio-based C4 platform chemical with versatile applications, including the production of 1,4-butanediol, tetrahydrofuran, and γ-butyrolactone. The non-conventional yeast Yarrowia lipolytica has garnered substantial interest as a robust cell factory for SA production at low pH. However, the high concentrations of SA, especially under acidic conditions, can impose significant stress on microbial cells, leading to reduced glucose metabolism viability and compromised production performance. Therefore, it is important to develop Y. lipolytica strains with enhanced SA tolerance for industrial-scale SA production.
An SA-tolerant Y. lipolytica strain E501 with improved SA production was obtained through adaptive laboratory evolution (ALE). In a 5-L bioreactor, the evolved strain E501 produced 89.62 g/L SA, representing a 7.2% increase over the starting strain Hi-SA2. Genome resequencing and transcriptome analysis identified a mutation in the 26S proteasome regulatory subunit Rpn1, as well as genes involved in transmembrane transport, which may be associated with enhanced SA tolerance. By further fine-tuning the glycolytic pathway flux, the highest SA titer of 112.54 g/L to date at low pH was achieved, with a yield of 0.67 g/g glucose and a productivity of 2.08 g/L/h.
This study provided a robust engineered Y. lipolytica strain capable of efficiently producing SA at low pH, thereby reducing the cost of industrial SA fermentation.
琥珀酸（SA）是一种重要的生物基 C4 平台化学品，具有广泛的应用，包括生产 1,4-丁二醇、四氢呋喃和 γ-丁内酯。非常规酵母解脂耶氏酵母作为一种在低 pH 值下生产 SA 的强大细胞工厂，已经引起了广泛的关注。然而，SA 的高浓度，尤其是在酸性条件下，会对微生物细胞造成很大的压力，导致葡萄糖代谢活力降低和生产性能受损。因此，开发具有增强的 SA 耐受性的解脂耶氏酵母菌株对于工业规模的 SA 生产非常重要。
通过适应性实验室进化（ALE）获得了一株具有提高的 SA 生产能力的耐 SA 解脂耶氏酵母 E501 菌株。在 5-L 生物反应器中，进化菌株 E501 生产了 89.62 g/L 的 SA，比起始菌株 Hi-SA2 提高了 7.2%。基因组重测序和转录组分析鉴定出 26S 蛋白酶体调节亚基 Rpn1 中的一个突变，以及参与跨膜运输的基因，这些基因可能与增强的 SA 耐受性有关。通过进一步微调糖酵解途径的通量，在低 pH 值下达到了迄今为止最高的 112.54 g/L 的 SA 产量，葡萄糖得率为 0.67 g/g，生产率为 2.08 g/L/h。
本研究提供了一种强大的工程化解脂耶氏酵母菌株，能够在低 pH 值下高效生产 SA，从而降低工业 SA 发酵的成本。
