Thermostable and alkaline-tolerant cellulase-free xylanase produced by thermotolerant Streptomyces sp Ab106

Cellulase-free xylanase was produced by Streptomyces sp. Ab106 using cane bagasse as the substrate at 55degreesC. Its maximum activity was 13 IU without cellulase and mannanase activities. Its profiles were investigated. Its optimum temperature and pH were 60degreesC and 6.0, respectively. More than 70% of its activity was remained at 60degreesC at pH 9. This enzyme was quite stable and exhibited an active of more than 70% for 144 h at 60degreesC, and of more than 80% for 144 h at 40degreesC, pH 9. This thermo-tolerant and alkaline-tolerant xylanase can be used in the pulp bleaching process.