We expressed a putative beta-galactosidase Asac 1390 from hyperthermophilic crenarchaeon Acidilobus saccharovorans in Escherichia coli and purified the recombinant enzyme. Asac 1390 is composed of 490 amino acid residues and showed high sequence similarity to family 1 glycoside hydrolases from various thermophilic Crenarchaeota. The maximum activity was observed at pH 6.0 and 93C. The half-life of the enzyme at 90C was about 7 hours. Asac 1390 displayed high tolerance to glucose and exhibits hydrolytic activity towards cellobiose and various aryl glucosides. The hydrolytic activity with p-nitrophenyl (pNP) substrates followed the order pNP-beta-D-galactopyranoside (328 U mg −1), pNP-beta-D-glucopyranoside (246 U mg −1), pNP-beta-D-xylopyranoside (72 U mg −1), and pNP-beta-D-mannopyranoside (28 U mg −1). Thus the enzyme was actually a multifunctional beta-glycosidase. Therefore, the utilization of Asac 1390 may contribute to facilitating the efficient degradation of lignocellulosic biomass and help enhance bioconversion processes.