The present invention relates to methods for the production of oligosaccharides in genetically modified bacterial host cells, as well as to the genetically modified host cells used in the methods. The genetically modified host cell comprises at least one recombinant glycosyltransferase, and at least one nucleic acid sequence coding for a protein enabling the export of the oligosaccharide.

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. Therefore, the microorganism has an industrial application prospect.

This disclosure is in the technical field of synthetic biology and metabolic engineering. More particularly, this disclosure is in the technical field of fermentation of metabolically engineered yeast or fungal cells. This disclosure describes a method for the extracellular production of a di- or oligosaccharide that is derived from UDP-GlcNAc by a yeast or fungal cell as well as the separation of the di- or oligosaccharide from the cultivation. Furthermore, this disclosure provides a metabolically engineered yeast or fungal cell for extracellular production of a di- or oligosaccharide that is derived from UDP-GlcNAc and that is synthesized in the cytosol.

The disclosure is in the technical field of synthetic biology and metabolic engineering. More particularly, the disclosure is in the technical field of metabolically engineered cells and use of the cells in a cultivation or fermentation. The disclosure describes a cell and a method for production of a di- and/or oligosaccharide. The cell comprises a pathway for production of the di- and/or oligosaccharide and is genetically modified for expression and/or overexpression of at least one set of multiple coding DNA sequences wherein the multiple coding DNA sequences within one set differ in nucleotide sequence and each encode a polypeptide, wherein the polypeptides have the same function and/or activity of interest. Furthermore, the disclosure provides for purification of the di- and/or oligosaccharide from the cultivation.

The present disclosure discloses the identification and introduction of a specific heterologous gene (denoted as smob), which encodes an -1,2-fucosyltransferase, into an LNT production strain to produce LNFP-I in particular.

The smob gene originates from the organism Sulfuriflexus mobilis (https://www.dsmz.de/collection/catalogue/details/culture/DSM-102939), which is a sulfur-oxidizing bacterium isolated from a brackish lake sediment.

FIG. 1 should accompany the abstract.

The present invention relates to primarily genetically modified microorganisms for in vivo synthesis of lacto-N-tetrose (LNT) and lacto-N-neotetrose (LNnT), and their fucosylated derivatives, and to uses of such microorganisms in methods of producing lacto-N-tetrose and lacto-N-neotetrose, and their fucosylated derivatives.

The present invention relates to methods for the production of oligosaccharides in genetically modified bacterial host cells, as well as to the genetically modified host cells used in the methods. The genetically modified host cell comprises at least one recombinant glycosyltransferase, and at least one nucleic acid sequence coding for a protein enabling the export of the oligosaccharide.

The present disclosure discloses the identification and introduction of a specific heterologous gene (denoted as smob), which encodes an -1,2-fucosyltransferase, into an LNT production strain to produce LNFP-I in particular. The smob gene originates from the organism Sulfuriflexus mobilis (https://www.dsmz.de/collection/catalogue/details/culture/DSM-102939), which is a sulfur-oxidizing bacterium isolated from a brackish lake sediment.