Polypeptides having transgalactosylating activity
The present invention relates to polypeptides, specifically polypeptides having transgalactosylating activity and nucleic acids encoding these, and their uses in e.g. dairy product.
1. A polypeptide having transgalactosylating activity consisting of:
a truncated polypeptide consisting of an amino acid sequence having at least 98% sequence identity to SEQ ID NO: 1 (amino acids 1 to 887), wherein the polypeptide has a ratio of transgalactosylating activity: β-galactosidase activity of at least 1.5.
2. The polypeptide according to claim 1 , wherein said truncated polypeptide consists of the amino acid sequence of SEQ ID NO: 1.
3. An isolated nucleic acid encoding the polypeptide according to claim 1 .
4. An expression vector comprising the nucleic acid according to claim 3 .
5. An isolated microbial cell for expressing the polypeptide according to claim 1 .
6. A method of expressing a polypeptide, the method comprising culturing the cell of claim 5 and optionally purifying the polypeptide from the cell.
7. A composition comprising the polypeptide of claim 1 , wherein the composition is a food composition or a dairy product.
8. A method for producing a food product by treating a substrate comprising lactose with a polypeptide as defined claim 1 .
9. A method for producing a dairy product by treating a milk-based substrate comprising lactose with a polypeptide as defined in claim 1 .
10. A process for producing galacto-oligosaccharides, comprising contacting a polypeptide of claim 1 with a milk-based solution comprising lactose.
11. A process for producing galacto-oligosaccharides, comprising contacting a purified polypeptide of claim 6 with a milk-based solution comprising lactose.