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, commercialization of 3-FL seems to be a bit sluggish due to its low content in human milk and poor yield in enlarged production. Here, an α-1,3-fucosyltransferase mutant was expressed in an engineered E. coli able to produce GDP-L-fucose, and gave 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 high 3-FL level with a titer of 35.72 g/L, a yield of 0.82 mol 3-FL/mol lactose, and a specific productivity of 0.46 g/L*h. Unexpectedly, the deletion of pfkA gene led to a much lower performance of 3-FL production than the control strain. Taken together, our production strategy finally achieved the highest 3-FL level in E. coli to date.

中文翻译：

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通过改良的从头途径提高工程化大肠杆菌中岩藻糖基化寡糖3-岩藻糖半乳糖的生物产量。

3-岩藻糖基乳糖（3-FL）和2'-岩藻糖基乳糖（2'-FL）是人乳中两个重要的岩藻糖基化低聚糖。对2'-FL的广泛研究使其正式批准用于婴儿配方食品。然而，由于3-FL的商业化似乎有点慢，这是因为其在母乳中的含量低，并且在扩大的产量中产量很低。在这里，α-1,3-岩藻糖基转移酶突变体在能够产生GDP-L-岩藻糖的工程化大肠杆菌中表达，并在5.0-L生物反应器中产生了有希望的3-FL滴度。为了增加辅助因子（NADPH和GTP）的利用率以优化3-FL的产生，zwf，pntAB和gsk基因连续过表达，最终导致3-FL含量高，效价为35.72 g / L，产量为0.82 mol 3-FL / mol乳糖，比生产率为0.46 g / L * h。不料，pfkA基因的缺失导致3-FL生产的性能比对照菌株低得多。综上所述，我们的生产策略最终达到了迄今为​​止大肠杆菌中最高的3-FL水平。