Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, P. R. China.
Science Island Branch of Graduate School , University of Science & Technology of China, Hefei, P. R. China.
Biosci Biotechnol Biochem. 2021 Jun 24;85(7):1772-1781. doi: 10.1093/bbb/zbab074.
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.
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低聚糖。对 2'-FL 的广泛研究使其获得了在婴儿配方奶粉中使用的官方批准。然而，由于其在母乳中的含量低，以及在扩大生产时产量不佳，3-FL 的发展有些缓慢。在这里，引入了一种α-1,3-岩藻糖基转移酶突变体到能够产生 GDP-L-岩藻糖的工程大肠杆菌（E. coli）中，在 5.0-L 生物反应器中获得了有希望的 3-FL 产量。为了增加优化 3-FL 生产所需的辅助因子（NADPH 和 GTP）的可用性，相继过表达了 zwf、pntAB 和 gsk 基因，最终使 3-FL 的水平提高，产量达到 35.72 g/L，3-FL 与乳糖的摩尔比为 0.82。出乎意料的是，pfkA 基因的缺失导致 3-FL 产量比对照菌株低得多。尽管如此，我们的策略仍在大肠杆菌中实现了迄今为止最高的 3-FL 水平。
