The invention relates to a method for selective crystallization of 2-fucosyllactose (2-FL) from an aqueous solution comprising 2-FL and one or more other fucosylated carbohydrates by adding acetic acid to the solution. The aqueous solution is separated from an aqueous culture medium prior to crystallization.

The present invention relates to methods for production of 2Fucosyllactose by a microbial system comprising a -1,2 fucosyltransferase (FucT2) polynucleotide and a Guanosine 5-diphospho--L-fucose (GDP-L-fucose) synthesis pathway using lactose as a substrate. Furthermore, the present invention relates to compositions comprising the microbial system.

An object of the present invention is to provide a modified protein having an ?1,2-fucosyltransferase activity and a method for producing a fucose-containing carbohydrate using the protein or a microorganism having an ability to produce the protein. According to the present invention, a fucose-containing carbohydrate such as 2-fucosyllactose can be more efficiently produced by using a protein having an ?1,2-fucosyltransferase activity and being modified to substitute a specific amino acid residue with another amino acid residue, or a microorganism having the protein or an ability to produce the protein, compared to the case of using a wild-type protein having an ?1,2-fucosyltransferase activity, or a microorganism having the protein or an ability to produce the protein.

A genetically engineered bacterium and a preparation method and use thereof are disclosed. The genetically engineered bacteria contain a gene encoding ?-1,2-fucosyltransferase, and a gene encoding a protein tag is connected to the gene encoding ?-1,2-fucosyltransferase; the protein tag is MBP, SUMO1, SUMO2 or TrxA, the amino acid sequence of the MBP is shown in SEQ ID NO: 2, the amino acid sequence of the SUMO1 is shown in SEQ ID NO: 3, the amino acid sequence of the SUMO2 is shown in SEQ ID NO: 4, the amino acid sequence of the TrxA is shown in SEQ ID NO: 5. Fermentation with the genetically engineered bacteria can greatly increase the yield of 2-fucosyllactose compared to the genetically engineered bacteria that only expresses ?-1,2-fucosyltransferase exogenously, and the yield can be more than doubled in a preferred case.

The present invention relates to genetically engineered organisms, especially microorganisms such as bacteria and yeasts, for the production of added value bio-products such as specialty saccharide, activated saccharide, nucleoside, glycoside, glycolipid or glycoprotein. More specifically, the present invention relates to host cells that are metabolically engineered so that they can produce said valuable specialty products in large quantities and at a high rate by bypassing classical technical problems that occur in biocatalytical or fermentative production processes.

The invention discloses a genetically engineered bacterium and a method for preparing a fucosylated oligosaccharide using the same. The method includes: transferring a fucosyl group of a donor to an oligosaccharide receptor by a fucosyltransferase heterologously expressed in a genetically engineered bacterium; wherein the donor is a nucleotide-activated donor, the fucosyltransferase has ?-1,2-fucosyltransferase activity; wherein, the fucosyltransferase is selected from one or more of the enzymes corresponding to NCBI Accession Numbers WP_109047124.1, RTL12957.1, MBP7103497.1, WP_120175093.1, RYE22506.1, WP_140393075.1 and HJB91111.1. The preparation method of the invention has high yield, greatly improved substrate conversion rate and product conversion rate, and has the potential to be applied to industrial production.

The present invention is in the technical field of synthetic biology and metabolic engineering. More particularly, the present invention is in the technical field of metabolically engineered cells and use of said cells in a cultivation, preferably a fermentation. The present invention describes a cell and a method for production of a compound. The cell expresses an alpha-1,2-fucosyltransferase that has galactoside alpha-1,2-fucosyltransferase activity on the galactose residue of Gal-b1,3-GlcNAc (LNB, lacto-N-biose). Furthermore, the present invention provides for purification of said compound from the cultivation.

This invention relates to a method of producing mixtures of various human milk oligosaccharides (HMOs) with unique HMO blend profiles, consisting predominantly of LNFP-I and LNT and of other HMOs in less significant amounts. The less abundant HMOs might be 2-FL, LNT-II or DFL. The strategies for achieving specific HMO blends include strain engineering and fermentation methods.

The present invention relates to methods for production of 2Fucosyllactose by a microbial system comprising a -1,2 fucosyltransferase (FucT2) polynucleotide and a Guanosine 5-diphospho--L-fucose (GDP-L-fucose) synthesis pathway using lactose as a substrate. Furthermore, the present invention relates to compositions comprising the microbial system.

Provided herein are host cells capable of producing a human milk oligosaccharide (HMO), such as yeast cells that are deficient in expression or activity of an endogenous oxidoreductase. Also provided are fermentation compositions including the disclosed host cells, as well as related methods of producing and recovering HMOs generated by the host cells.