摘要
Human milk oligosaccharides (HMOs) are beneficial for infants' health and growth. As one of the most abundant oligosaccharides in human milk, 2'-fucosyllactose (2'-FL) has been approved to supplement in infant formula. Microbial synthesis of 2'-FL achieved in E. coli tends to use a T7-expression system for the heterologous expression of the fucosyltransferase and/or enzymes involved in fucose metabolism. In this paper, we report a novel bioconversion route of 2'-FL by engineering a low pH triggered colanic acid (CA) synthetic pathway, found in E. coli. S17 - 3, which supplies GDP-L-fucose for in vivo 2'-FL formation catalyzed by the heterologous alpha-1,2-fucosyltransferases. In medium added with 10 g/L lactose and 20 g/L glycerol, recombinant S17 - 3 was able to produce 0.617 g/L of 2'-FL. The concentration of 2'-FL came to 1.029 g/L when a heterologous pathway for the synthesis of polyhydroxybutyrate was additionally introduced in the engineered S17 - 3.
