Abstract: Disclosed are a construction method and application of a microorganism capable of realizing high production of lacto-N-neotetraose, belonging to the field of microbial genetic engineering. Coding genes of ß-1,3-acetyl glucosamine transferase, ß-1,4-galactosyl transferase and/or UDP-glucose 4 epimerase are over-expressed on the basis of a strain which is previously constructed by the team and is subjected to related-gene knockout, thus enabling the strain to have a synthesis capability of producing the lacto-N-neotetraose. The present disclosure accurately regulates the carbon flux of a metabolic pathway and relieves the metabolic stress by screening the high-efficiency ß-1,4-galactosyl transferase gene and regulating the expression of IgtA, Aa-?-1,4-GalT and galE in a lacto-N-neotetraose synthesis pathway in a combined manner. In a shake flask experiment, the lacto-N-neotetraose production capacity of Escherichia coli is 0.91 g/L. The lacto-N-neotetraose yield in a 3 L fermentation tank reaches 12.14 g/L.

Abstract: Disclosed are a construction method and application of a microorganism capable of realizing high production of lacto-N-neotetraose, belonging to the field of microbial genetic engineering. Coding genes of ?-1,3-acetyl glucosamine transferase, ?-1,4-galactosyl transferase and/or UDP-glucose 4 epimerase are over-expressed on the basis of a strain which is previously constructed by the team and is subjected to related-gene knockout, thus enabling the strain to have a synthesis capability of producing the lacto-N-neotetraose. The present disclosure accurately regulates the carbon flux of a metabolic pathway and relieves the metabolic stress by screening the high-efficiency ?-1,4-galactosyl transferase gene and regulating the expression of IgtA, Aa-?-1,4-GalT and galE in a lacto-N-neotetraose synthesis pathway in a combined manner. In a shake flask experiment, the lacto-N-neotetraose production capacity of Escherichia coli is 0.91 g/L. The lacto-N-neotetraose yield in a 3 L fermentation tank reaches 12.14 g/L.