초록
We here describe a unique β-D-glucosidase (BGL; Blon_0625) derived from Bifidobacterium longum subsp. infantis ATCC 15697. The Blon_0625 gene was expressed by recombinant Escherichia coli. Purified recombinant Blon_0625 retains hydrolyzing activity against both p-nitrophenyl-β-D-glucopyranoside (pNPG; 17.3+/-0.24Umg<SUP>-1</SUP>) and p-nitrophenyl-β-D-xylopyranoside (pNPX; 16.7+/-0.32Umg<SUP>-1</SUP>) at pH 6.0, 30<SUP>o</SUP>C. To best of our knowledge, no previously described BGL retains the same level of both pNPGase and pNPXase activity. Furthermore, Blon_0625 also retains the activity against 4-nitrophenyl-α-l-arabinofranoside (pNPAf; 5.6+/-0.09Umg<SUP>-1</SUP>). In addition, the results of the degradation of phosphoric acid swollen cellulose (PASC) or xylan using endoglucanase from Thermobifida fusca YX (Tfu_0901) or xylanase from Kitasatospora setae KM-6054 (KSE_59480) show that Blon_0625 acts as a BGL and as a β-D-xylosidase (XYL) for hydrolyzing oligosaccharides. These results clearly indicate that Blon_0625 is a multi-functional glycoside hydrolase which retains the activity of BGL, XYL, and also α-l-arabinofuranosidase. Therefore, the utilization of multi-functional Blon_0625 may contribute to facilitating the efficient degradation of lignocellulosic materials and help enhance bioconversion processes.