Alpha (1,3) fucosyltransferases for use in the production of fucosylated oligosaccharides

1. A method for producing a fucosylated oligosaccharide in a bacterium comprising expressing a lactose-accepting α(1,3) fucosyltransferase enzyme in a host bacterium, wherein the amino acid sequence of said enzyme comprises at least 90% identity to full length CafC (SEQ ID NO: 2), thereby producing an α(1,3) fucosylated oligosaccharide.

2. The method of claim 1 , wherein the amino acid sequence of said enzyme comprises at least 95% sequence identity to full length CafC (SEQ ID NO: 2).

3. The method of claim 1 , wherein said amino acid sequence comprises at least 50% or at least 80% identity to the CafC active site region 2 (residues 116-202 of SEQ ID NO:2).

4. The method of claim 1 , wherein

(a) said α(1,3) fucosyltransferase enzyme comprises CafC, or a functional variant or fragment thereof; or

(b) said α(1,3) fucosyltransferase enzyme comprises the amino acid sequence of SEQ ID NO: 2 (CafC), or a functional fragment thereof.

5. The method of claim 1 , further comprising providing the bacterium a nucleic acid construct comprising an isolated nucleic acid encoding the α(1,3) fucosyltransferase enzyme.

6. The method of claim 5 , wherein said nucleic acid is operably linked to one or more heterologous control sequences that direct the production of the enzyme in the bacterium.

7. The method of claim 6 , wherein said heterologous control sequence comprises a bacterial promoter and operator, a bacterial ribosome binding site, a bacterial transcriptional terminator, or a plasmid selectable marker.

8. The method of claim 1 , further comprising retrieving the fucosylated oligosaccharide from said bacterium or from a culture supernatant of said bacterium.

9. The method of claim 1 , wherein said fucosylated oligosaccharide comprises 3-fucosyllactose (3-FL) or lactodifucotetraose (LDFT).

10. The method of claim 1 , wherein said bacterium is E. coli.

11. The method of claim 10 , further comprising culturing said bacterium in the presence of tryptophan and in the absence of thymidine.

12. The method of claim 10 , wherein an endogenous lacZ gene and an endogenous lacI gene of said bacterium are deleted.

13. The method of claim 12 , wherein said bacterium comprises a lacIq gene promoter immediately upstream of a lacY gene.

14. The method of claim 10 , wherein an endogenous wcaJ gene of said bacterium is deleted.

15. The method of claim 10 , wherein said bacterium comprises a null mutation in a lon gene.

16. The method of claim 10 , wherein said bacterium accumulates intracellular lactose in the presence of exogenous lactose.

17. The method of claim 10 , wherein said bacterium accumulates intracellular guanosine diphosphate (GDP)-fucose.

18. The method of claim 10 , wherein said bacterium further expresses an α(1,2) fucosyltransferase enzyme, an α(1,4) fucosyltransferase enzyme, and/or an additional α(1,3) fucosyltransferase enzyme.

19. The method of claim 5 , wherein the nucleic acid construct further comprises an isolated nucleic acid encoding an α(1,2) fucosyltransferase enzyme and/or an additional α(1,3) fucosyltransferase enzyme.

20. The method of claim 10 , further comprising culturing said bacterium in the presence of a nitrogen-rich additive.

21. The method of claim 20 , wherein the nitrogen-rich additive comprises casamino acids (CAA), yeast extract (YE), or a protein hydrolysate.

22. The method of claim 1 , wherein said α(1,3) fucosyltransferase enzyme comprises the amino acid sequence of SEQ ID NO: 2 (CafC).

23. The method of claim 1 , wherein the method further comprises culturing the bacterium in the presence of lactose to produce the fucosylated oligosaccharide.