Combinatorial metabolic engineering and tolerance evolving of Escherichia coli for high production of 2'-fucosyllactose.

2'-Fucosyllactose (2'-FL) is an important functional ingredient of advanced infant formula. Here, Escherichia coli MG1655 was engineered for achieving high 2'-FL production. The expressions of 2'-FL synthesis pathway genes were finely regulated with single or multi copies according to rate-limiting enzyme diagnosis.