State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, China.
School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu 214122, China.
J Agric Food Chem. 2024 Nov 20;72(46):25836-25846. doi: 10.1021/acs.jafc.4c08711. Epub 2024 Nov 7.
Human milk oligosaccharides (HMOs) have attracted considerable interest for their vital role in supporting infant health. Among these, sialyllacto--tetraose c (LST c), a pentasaccharide with the structure Neu5Ac(α2,6)Gal(β1,4)GlcNAc(β1,3)Gal(β1,4)Glc, stands out due to its critical importance in the development and application of complex HMOs. In this study, we employed multivariate modular metabolic engineering (MMME) to screen for efficient sialyltransferases and balance metabolic fluxes, successfully constructing strains capable of LST c biosynthesis. Additionally, by blocking competing pathway genes, enhancing the supply of UDP-GlcNAc and UDP-Gal precursors, and establishing a CTP cofactor regeneration system, we developed a high-yielding strain, W15. This strain achieved an LST c titer of 220.9 mg/L in shake flask cultures. In a 3-L fed-batch fermentation, the LST c concentration reached 922.2 mg/L, with a productivity of 10.25 mg/L/h and a specific yield of 38.70 mg/g DCW. This research provides an effective strategy for producing LST c in microbial cell factories.
人乳寡糖（HMOs）因其在支持婴儿健康方面的重要作用而引起了极大的关注。在这些寡糖中，唾液酸乳糖四糖 c（LST c）是一种具有 Neu5Ac（α2,6）Gal（β1,4）GlcNAc（β1,3）Gal（β1,4）Glc 结构的五糖，因其在复杂 HMOs 的发展和应用中的重要性而备受关注。在本研究中，我们采用多元模块化代谢工程（MMME）筛选高效的唾液酸转移酶并平衡代谢通量，成功构建了能够合成 LST c 的菌株。此外，通过阻断竞争途径基因、增强 UDP-GlcNAc 和 UDP-Gal 前体的供应，并建立 CTP 辅因子再生系统，我们开发了一株高产 LST c 的菌株 W15。该菌株在摇瓶培养中达到了 220.9 mg/L 的 LST c 产量。在 3-L 分批补料发酵中，LST c 浓度达到 922.2 mg/L，生产强度为 10.25 mg/L/h，比产率为 38.70 mg/g DCW。这项研究为在微生物细胞工厂中生产 LST c 提供了一种有效的策略。
