Low molecular weight endo-xylanase from Bacillus pumilus SSP-34 was purified to homogeneity using ion exchange and size exclusion chromatographies. Xylanases were isolated by novel purification protocol which includes the use of anion exchange matrix such as DEAE Sepharose CL 6B with less affinity towards enzyme protein. The purified B. pumilus SSP-34 have a molecular weight of 20 kDa, with optimum pH and temperature at 6.0 and 50 A degrees C, respectively. The enzyme was stable at 50 A degrees C for 30 min. It showed remarkable stability at pH values ranging from 4.5 to 9 when the reaction was carried out at 50 A degrees C. K (m) and V (max) values, determined with oats spelts xylan were 6.5 mg ml(-1) and 1,233 mu mol min(-1) mg(-1) protein, respectively, and the specific activity was 1,723 U mg(-1).