Synthesis of alpha-galacto-oligosaccharides by a cloned alpha-galactosidase from Bifidobacterium adolescentis

A genomic library of Bifidobacterium adolescentis was constructed in Escher ichia coli and a gene encoding an alpha-galactosidase was isolated. The ide ntified open reading frame showed high similarity and identity with bacteri al alpha-galactosidases, which belong to Family 36 of the glycosyl hydrolas es. For the purification of the enzyme from the medium a single chromatogra phy step was sufficient. The yield of the recombinant enzyme was 100 times higher than from B. adolescentis itself. In addition to hydrolytic activity the alpha-galactosidase showed transglycosylation activity and can be used for the production of alpha-galacto-oligosaccharides.