State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China.
Bloomature Biotechnology Corporation, Limited, Beijing 102629, People's Republic of China.
J Agric Food Chem. 2024 Apr 3;72(13):7179-7186. doi: 10.1021/acs.jafc.3c09162. Epub 2024 Mar 23.
Lacto--neotetraose (LNnT), a prominent neutral human milk oligosaccharide (HMO), serves as a pivotal structural element in complex HMO biosynthesis. Given its promising health effects for infants, the biosynthesis of LNnT is garnering greater interest. Using a previously engineered strain as a chassis, a highly effective LNnT producer was constructed. First, LNnT synthesis in MG1655 was achieved by introducing β1,3--acetylglucosaminyltransferase LgtA and β1,4-galactosyltransferase CpsIaJ, coupled with the optimization of enzyme expression levels using various promoters. Subsequently, underwent disruption, and the gene was enhanced by replacing its promoter with P or P. Then, a lux-type quorum sensing (QS) system was applied to achieve varied metabolic regulation. Additionally, systematic optimization of the QS promoters was conducted to further improve the LNnT titer in the shake flask. Finally, the extracellular titer of LNnT was 20.33 g/L, accompanied by a productivity of 0.41 g/L/h.
乳-N-新四糖（LNnT）是一种重要的中性人乳寡糖（HMO），是复杂 HMO 生物合成的关键结构单元。鉴于其对婴儿健康的积极影响，LNnT 的生物合成越来越受到关注。本研究使用先前工程化的菌株作为底盘，构建了一种高效的 LNnT 生产菌株。首先，通过引入β1,3--乙酰氨基葡萄糖基转移酶 LgtA 和β1,4-半乳糖基转移酶 CpsIaJ，在 MG1655 中实现了 LNnT 的合成，并通过各种启动子优化了酶表达水平。随后，敲除了，并通过用 P 或 P 替换其启动子增强了 基因。然后，应用 lux 型群体感应（QS）系统实现了不同的代谢调控。此外，还对 QS 启动子进行了系统优化，进一步提高了摇瓶中的 LNnT 效价。最终，胞外 LNnT 的效价达到 20.33 g/L，产物得率为 0.41 g/L/h。
