BACKGROUNDXylanase is the key enzyme involved in the conversion of lignocelluloses. RESULTSAn extracellular xylanase from Streptomyces althioticusLMZM submerged culture medium using corncob was purified and characterized. The enzyme was purified 12.65-fold through ammonium sulphate precipitation, Sephadex G-25, DEAE cellulose chromatography, followed by gel filtration through a Sephadex G-100 column. The molecular mass of purified xylanase was about 31.75 kDa. The enzyme was an endo-xylanase, as it degraded xylan to xylooligosaccharide with non-xylose after 24h. The purified enzyme showed optimum activity at 60 degrees C and at pH 8.0 but remained active over a wide range of pH (6.0-11.0) and temperature (40-80 degrees C). The enzyme retained 98.72% and 69.50% residual enzyme activity at pH 8.0 and at 60 degrees C after 1h. The K-m and V-max values were found to be 43.03mg mL(-1) and 312.5 mu mol (min mg(-1)), respectively. The enzyme was remarkably activated by cysteine and Cu2+, and its activity was strongly inhibited by Hg2+. The brightness of kraft pulp was improved by this xylanase. CONCLUSIONSince the enzyme was active over a wide range of pH, and remained active at high temperature, it could find potential uses in biobleaching processes in pulp paper industries and in the production of xylooligosacaharides. (c) 2015 Society of Chemical Industry