A method for synthesizing lacto-N-biose and belongs to the technical field of bioengineering and oligosaccharide synthesis. A multi-enzyme catalytic system with good biological safety and wide application, and an ATP regeneration cycle system is introduced into a multi-enzyme reaction system, so that the synthesis of lacto-N-biose and the utilization rate of substrates are improved. A novel lacto-N-biose synthetic route lays a foundation for large-scale industrial production of lacto-N-biose and has important economic values and social benefits. At the same time, the synthetic method is efficient, mild, simple, easy to operate, low in cost and suitable for industrial production, and has a high practical application value.

Provided herein are ?-1,3-linked biopolymers (acholetin polysaccharides). Furthermore, provided herein are enzymatic methods and systems for producing ?-1,3-linked oligosaccharides and polysaccharides using ?-1,3-N-acetylglucosaminide phosphorylase (Acholetin phosphorylase (AchP)). The AchP was sourced from the genome of the cell wall-less Mollicute bacterium, Acholeplasma laidlawii and was found to synthesize ?-1,3-linked N-acetylglucosamine (GlcNAc) or N-acetylgalactosamine (GalNAc) oligomers using the donor. ?-N-acetylglucosamine 1-phosphate (GlcNAc1-P) or N-acetylgalactosamine 1-phosphate (GalNAc1-P).

The present application provides a polypeptide having glycoside hydrolase activity, a related nucleic acid product and enzyme product thereof, a preparation method therefor, and use thereof in synthesis of human milk oligosaccharides (HMOS), particularly lacto-N-biose (LNB). The polypeptide having glycoside hydrolase activity of the present application is used as a catalyst, and can efficiently catalyze the reaction of acetylglucosamine or a carbohydrate having an acetylglucosamine group with a glycosyl donor to generate the lacto-N-biose (LNB). Moreover, a process for producing the LNB based on the peptide is simple and convenient to operate and has a significant increase in production efficiency, thus being more suitable for industrial production.

A glycoside hydrolase, relating to the technical field of enzyme engineering/gene engineering. Provided are an enzyme of a GH112 glycoside hydrolase family, and an application of synthesizing human milk oligosaccharides (HMOs) by using an enzyme of a GH112 glycoside hydrolase family. A synthesis reaction is catalyzed by using the enzyme of the glycoside hydrolase family 112 (GH112) that is classified according to a Carbohydrate-Active-Enzymes (CAZy) database (http://www.cazy.org); and lacto-N-tetraose (LNT) is generated in an aqueous solution comprising lactose and/or galactose and/or galactose-1-phosphate and lacto-N-triose (LNTII). The enzyme of the glycoside hydrolase family 112 (GH112), and the preparation method therefor and the application thereof provided by the present invention have economic and social values.

A mature polypeptide sequence the amino acid sequence of which has at least 60%, or at least 70%, or at least 75%, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 97%, or at least 98%, or at least 99%, or 100% sequence identity to at least one of the sequences selected from SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, and SEQ ID NO: 10. The mature polypeptide sequence has a relatively high capability to catalyze synthesis of lactose-N-tetrasaccharide.