Abstract:Human milk oligosaccharides play a crucial role in promoting infant health, safeguarding newborns against infection and inflammation, and serving as the optimal natural source of nutrition for infants. Among these oligosaccharides, 2’-fucosylactose (2’-FL) stands out as a prominent constituent with the highest content. Due to its significant application potential in medicine and infant formula production, 2’-FL has rapidly emerged as a focal point of research interest. Natural product extraction and chemical synthesis are the main methods of traditional synthesis of 2’-FL, but these two methods are difficult to extract 2’-FL in large quantities, and there is serious pollution. Consequently, there is growing attention towards employing whole cell fermentation as an environmentally friendly approach that offers mild reaction conditions for efficient 2’-FL production. By heterologously expressing polyphosphate-dependent mannose kinase AsPPGMK and α-1,2-fucosyltransferase in Escherichia coli while co-expressing key enzymes involved in the synthesis pathway and knocking out the gene encoding UDP-glucose lipid carrier transferase wcaJ to prevent intermediate metabolite degradation, we successfully enhanced the yield of 2’-FL. Ultimately, through optimization of catalytic transformation conditions, the addition of 200 mmol/L substrate to the 100 mL system further enhanced the yield of 2’-FL to 79 g/L in a yield of 81% in 8 h.
