3-fucosyllactose (3-FL) and 2'-fucosyllactose (2'-FL), are two important fucosylated oligosaccharides in human milk. Extensive studies on 2'-FL enabled its official approval for use in infant formula. However, development of 3-FL has been somewhat sluggish due to its low content in human milk and poor yield in enlarged production. Here, an α-1,3-fucosyltransferase mutant was introduced into an engineered Escherichia coli (E. coli) capable of producing GDP-L-fucose, leading to a promising 3-FL titer in a 5.0-L bioreactor. To increase the availability of cofactors (NADPH and GTP) for optimized 3-FL production, zwf, pntAB, and gsk genes were successively overexpressed, finally resulting in a higher 3-FL level with a titer of 35.72 g/L and a yield of 0.82 mol 3-FL/mol lactose. Unexpectedly, the deletion of pfkA gene led to a much lower performance of 3-FL production than the control strain. Still, our strategy achieved the highest 3-FL level in E. coli to date.

中文翻译：

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通过改进的从头途径增强工程大肠杆菌中岩藻糖基化寡糖 3-岩藻糖基乳糖的生物生产。

3-岩藻糖基乳糖 (3-FL) 和 2'-岩藻糖基乳糖 (2'-FL) 是母乳中两种重要的岩藻糖基化寡糖。对 2'-FL 的广泛研究使其正式批准用于婴儿配方奶粉。然而，3-FL在人乳中的含量低，扩大生产时产量低，因此发展有些缓慢。在这里，将 α-1,3-岩藻糖基转移酶突变体引入能够产生 GDP-L-岩藻糖的工程大肠杆菌（E.coli）中，从而在 5.0-L 生物反应器中产生有希望的 3-FL 滴度。为了提高辅助因子（NADPH 和 GTP）的可用性以优化 3-FL 生产，依次过表达 zwf、pntAB 和 gsk 基因，最终导致更高的 3-FL 水平，滴度为 35.72 g/L，产量为0.82 mol 3-FL/mol 乳糖。不料，pfkA 基因的缺失导致 3-FL 生产性能比对照菌株低得多。尽管如此，我们的策略在大肠杆菌中达到了迄今为​​止最高的 3-FL 水平。