A low molecular weight xylanase from Bacillus strain CSB40, isolated from traditional Korean food and produced in beechwood xylan, was biochemically and thermodynamically characterized. It was purified 8.12-fold with a 15.88 % yield using DEAE sepharose fast flow, and it was determined to have a mass of 27 kDa via sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and xylan zymography. The purified xylanase was optimally active at 50 A degrees C and pH 6 and stable over a wide range of pH (4.5-12.5). The N-terminal amino acid sequence of xylanase was GIQQGDDGKL. The activation energy for beechwood xylan hydrolysis was 29.39 kJmol(-1) with k (cat) value of 927.582 x 10(2) s(-1). K (m) and V (max) were 0.080 mg/ml and 794.63 mmol min(-1) mg(-1). The analysis of other thermodynamic parameters like aH, aG, aS, Q(10), aG(E-S), and aG(E-T) also supported the spontaneous formation of products, greater hydrolytic efficiency, and feasibility of enzymatic reaction, which also ratifies the novelty of this xylanase. The enzyme was strongly activated by Zn2+ and inhibited by Cu2+. The principal hydrolyzed end-products of this xylanase are xylobiose, xylotriose, and xylotetrose, which can be used in the pharmaceutical industry and as prebiotic in food.