Mass production of bacterial alpha 2,6-sialyltransferase and enzymatic syntheses of sialyloligosaccharides.

To supply alpha 2,6-sialyltransferase for the large-scale synthesis of sialoside, we investigated culture conditions for the production of sialyltransferase 0160. The addition of galactose and beef extract, and control of the pH of the culture medium were effective on the production of sialyltransferase 0160. The maximal enzyme productivity reached 550 units/L. Using a crude extract of Photobacterium damsela JT0160 cells as an enzyme source, enzymatic syntheses were performed with mono- and di-saccharides as the sialyl acceptors. It was clarified that a crude extract of P. damsela JT0160 cells can be used as an synthetic catalyst for the enzymatic synthesis of sialyloligosaccharides. Furthermore, the enzyme assay showed that sialyltransferase 0160 could transfer NeuAc to not only N-linked but also O-linked carbohydrate chains. These results indicated that an abundant supply of sialyltransferase 0160 and its broad specificity make possible the synthesis of sialoside on a large scale.