Synthesis of β-d-fucosylglucose by β-d-glucosidase i of bifidobacterium breve clb and assimilation by bifidobacteria

The P-nitrophenol-releasing activity, from P-nitrophenyl (p-NP) β-D-fucoside, of β-D-glucosidase I from Bifidobacterium breve clb was enhanced by the addition of many kinds of sugars and alcohols, suggesting the occurrence of a β-D-fucosyl transferring reaction. The enhancement on glucose addition was dependent on the reaction pH, and the concentrations of p-NP β-D-fucoside and glucose, and the activity reached 430% when 100 mM glucose was added to the mixture containing 20 mM p-NP β-D- fucoside at pH 4.5. A mixture of transfer products was separated from the other constituents by activated charcoal column chromatography. Further purification of the mixture by paper and thin-layer chromatographies gave four oligosaccharides, which were identified as β- D-fucosylglucoses with β 1→2, β1→3, β1→4 and β 1→6, linkages from the absorption spectra obtained with the phenol-sulfuric acid method, and the results of acid and enzymatic hydrolyses, and methylation analyses. The mixture of oligosaccharides was well assimilated by many bifidobacteria but not by any other intestinal bacteria tested.