Xylanase refers to a type of enzyme which can hydrolyze xylans into xylooligosaccharides and d - xylose . it broadly exists in microorganism and has wide commerical application in industrial processes , such as feed , paper , foodstuff , medicine and energy industries . the xylanase gene xynb encoding the native protein of xylanase from streptomyces olivaceoviridis a1 was cloned into pichia pastoris expression vector ppic9 a 我们将来源于橄榄绿链霉菌a1 ( streptomycesolivaceoviridisa1 )的木聚糖酶基因xynb的成熟蛋白编码序列克隆到毕赤酵母表达载体ppic9中，转化pichiapastorisgs115得到重组子，实现了木聚糖酶基因xynb的高效表达，表达产物能有效分泌且具有正常的生物学活性。
