To degrade plant hemicelluloses fungi employ beta-xylosidases to hydrolyse xylooligosaccharides, released by endo-xylanases, into xylose. We have expressed the beta-xylosidase from Neurospora crassa in Pichia pastoris under the control of alcohol oxidase 1 (AOX1) promoter. The recombinant enzyme is optimally active at 50 degrees C and pH 5.0 with K-m and V-max values of 8.9 mM and 1052 mu mol min(-1) mg(-1) respectively against 4-nitrophenyl beta-xylopyranoside. Xylose is a non-competitive inhibitor with a K-1 of 1.72 mM. The enzyme is characterised to be an exo-cutting enzyme releasing xylose from the non-reducing ends of beta-1,4 linked xylooligosaccharides (X-2, X-3 and X-4) but also capable of transxylosilation. Catalytic conversion of X2, X3 and X4 decreases (V-max and k(cat)) with increasing chain length. (c) 2014 Elsevier Inc. All rights reserved.