Chemical structure of xylan in cotton-seed cake.

Enzymatic hydrolysis ofxylan, and isolation ofhydrolysis products. Cotton-seed cake, lOOOg of air-dried matter (containing 458g of total pentose analyzed by the orcinol-HCl method),1) was soaked in 600 ml of2% NaOH solution at room temperature for 4 days, to promote the enzymatic susceptibility of xylan in the cake. The alkali-treated cake (790g of air-dried matter containing 394g of total pentose), after it was washed with water and air-dried, was added to a solution of xylanase from Streptomyces sp. E-86 (800ml containing 220,000units),