Abstract: Wheat straw was pretreated by crude xylanase prior to chemical pulping, and effects of enzyme treatment on chemical composition of wheat straw and fiber length of its chemical pulp were investigated. The results show that contents of hot-water extractive and 1% NaOH extractive were increased, and alcohol-benzene extractive content was lowered by xylanase treatment. Xylanase treatment had a slight influence on Klasson lignin content, but lowered pentosan content.The extraction with low consistency sodium hydroxide solution after enzymatic treatment led to the decreases of Klasson lignin and pentosan contents effectively. Compared to the control, chemical pulp from xylanase-pretreated wheat straw has a longer length of fiber.

Key words: xylanase treatment, alkali extraction, fiber length, wheat straw