Abstract:A glycoside hydrolase (GH) 11 family xylanase gene (TaXyn11A) from Trichoderma asperellum was cloned and heterologously expressed in Escherichia coli. The gene had an open reading frame of 672 bp, encoding 223 amino acids. The deduced amino acid sequence shares the highest identity (85.2%) with the GH 11 family xynII (NCBI accession No. B5A7N4.1) from Trichoderma harzianum C4. The crude enzyme was purified by one-step to homogeneity by Ni-NTA with a molecular mass of 24.2 kDa. The recombinant xylanase (TaXyn11A) was biochemically characterized, and the results showed that TaXyn11A was an acidic and mesophilic enzyme, having optimal pH and temperature of pH 5.0 and 50℃, respectively. The stability of the enzyme was between the pH range of 4.0~10.0 and temperature lower than or equal to 45℃, and its half-life at 45℃ was 14.3h. The enzyme was activated by EDTA, Mn2+ and Cr3+, while strongly inhibited by SDS and CTAB. Analyses for substrate specificities and hydrolysis properties indicated that TaXyn11A exhibited great sensitivity towards oat xylan, wheat arabinoxylan, beechwood xylan and birchwood xylan, with specific activities of 989.6,727.6,706.0 and 484.5U·mg-1, respectively, and the enzyme hydrolyzed verious xylans for 12h to mainly yield xylooligosaccharides with polymerization degree of 2~6. The favorable properties of TaXyn11A may make it a good candidate in xylooligosaccharides production in industry.