The disclosure is in the technical field of synthetic biology and metabolic engineering. More particularly, the disclosure is in the technical field of cultivation or fermentation of metabolically engineered cells. The disclosure describes a cell metabolically engineered for production of a mixture of at least four different neutral non-fucosylated oligosaccharides. Furthermore, the disclosure provides a method for the production of a mixture of at least four different neutral non-fucosylated oligosaccharides by a cell as well as the purification of at least one of the oligosaccharides from the cultivation.

The invention discloses a genetically engineered bacterium and its application in the preparation of sialyllactose. The genetically engineered bacterium has an N-acetylneuraminic acid biosynthesis pathway, includes multiple copies of a gene neuB for encoding sialic acid synthase, and the gene neuB is initiated for expression by a strong promoter. Using the genetically engineered bacteria of the invention to produce sialyllactose has the advantages of high yield and low overall cost.

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 present invention relates to the field of bio-production of chondroitin. There is a need in the art for chondroitin production methods allowing its highly efficient synthesis and secretion. The solution proposed in the present invention is the use of a recombinant cell, in particular a recombinant yeast, comprising many modifications as described in the present text. The present invention further proposes methods allowing the bio-production of chondroitin using the recombinant cell, in particular a recombinant yeast, of the invention.

The present invention provides a method for promoting N-acetylglucosamine synthesis by using the GlcN6P responsive element. In the present invention, Bacillus subtilis BSGNY-P.sub.veg-glmS-P.sub.43-GNA1 is used as a starting strain, in which a CRISPRi system regulated by GlcN6P responsive element is integrated into the genome to dynamically weaken the N-acetylglucosamine synthesis competitive pathway; a GlcN6P responsive promoter is used to regulate the expression of GNA1 on the plasmid to dynamically regulate the N-acetylglucosamine synthesis pathway; and the key gene alsSD involved in the acetoin synthesis pathway is knocked out. During fed-batch fermentation with this strain in a 15 L fermenter, the production of N-acetylglucosamine reaches 131.6 g/L and no by-product acetoin is accumulated, which lays a foundation for the production of GlcNAc by industrial fermentation.

This disclosure is in the technical field of synthetic biology and metabolic engineering. More particularly, this disclosure is in the technical field of cultivation or fermentation of metabolically engineered cells. This disclosure describes a cell metabolically engineered for production of a mixture of at least three different oligosaccharides. Furthermore, this disclosure provides a method for the production of a mixture of at least three different oligosaccharides by a cell as well as the purification of at least one of the oligosaccharides from the cultivation.

Production of a mixture of neutral fucosylated oligosaccharides by a cell. The disclosure is in the technical field of synthetic biology and metabolic engineering. More particularly, the disclosure is in the technical field of cultivation or fermentation of metabolically engineered cells. The disclosure describes a cell metabolically engineered for production of a neutral mixture of at least four different neutral fucosylated oligosaccharides. Furthermore, the disclosure provides a method for the production of a neutral mixture of at least four different neutral fucosylated oligosaccharides by a cell as well as the purification of at least one of the neutral oligosaccharides from the cultivation.